Shale Gas and Tight Oil: A Panacea for the Energy Woes of America?

Science.gov (United States)

Hughes, J. D.

2012-12-01

Shale gas has been heralded as a "game changer" in the struggle to meet America's demand for energy. The "Pickens Plan" of Texas oil and gas pioneer T.Boone Pickens suggests that gas can replace coal for much of U.S. electricity generation, and oil for, at least, truck transportation1. Industry lobby groups such as ANGA declare "that the dream of clean, abundant, home grown energy is now reality"2. In Canada, politicians in British Columbia are racing to export the virtual bounty of shale gas via LNG to Asia (despite the fact that Canadian gas production is down 16 percent from its 2001 peak). And the EIA has forecast that the U.S. will become a net exporter of gas by 20213. Similarly, recent reports from Citigroup and Harvard suggest that an oil glut is on the horizon thanks in part to the application of fracking technology to formerly inaccessible low permeability tight oil plays. The fundamentals of well costs and declines belie this optimism. Shale gas is expensive gas. In the early days it was declared that "continuous plays" like shale gas were "manufacturing operations", and that geology didn't matter. One could drill a well anywhere, it was suggested, and expect consistent production. Unfortunately, Mother Nature always has the last word, and inevitably the vast expanses of purported potential shale gas resources contracted to "core" areas, where geological conditions were optimal. The cost to produce shale gas ranges from 4.00 per thousand cubic feet (mcf) to 10.00, depending on the play. Natural gas production is a story about declines which now amount to 32% per year in the U.S. So 22 billion cubic feet per day of production now has to be replaced each year to keep overall production flat. At current prices of 2.50/mcf, industry is short about 50 billion per year in cash flow to make this happen4. As a result I expect falling production and rising prices in the near to medium term. Similarly, tight oil plays in North Dakota and Texas have been heralded

Naturally fractured tight gas reservoir detection optimization

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-04-30

In March, work continued on characterizing probabilities for determining natural fracturing associated with the GGRB for the Upper Cretaceous tight gas plays. Structural complexity, based on potential field data and remote sensing data was completed. A resource estimate for the Frontier and Mesa Verde play was also completed. Further, work was also conducted to determine threshold economics for the play based on limited current production in the plays in the Wamsutter Ridge area. These analyses culminated in a presentation at FETC on 24 March 1999 where quantified natural fracture domains, mapped on a partition basis, which establish ''sweet spot'' probability for natural fracturing, were reviewed. That presentation is reproduced here as Appendix 1. The work plan for the quarter of January 1, 1999--March 31, 1999 comprised five tasks: (1) Evaluation of the GGRB partitions for structural complexity that can be associated with natural fractures, (2) Continued resource analysis of the balance of the partitions to determine areas with higher relative gas richness, (3) Gas field studies, (4) Threshold resource economics to determine which partitions would be the most prospective, and (5) Examination of the area around the Table Rock 4H well.

Tight gas sand tax credit yields opportunities

International Nuclear Information System (INIS)

Lewis, F.W.; Osburn, A.S.

1991-01-01

The U.S. Internal Revenue Service on Apr. 1, 1991, released the inflation adjustments used in the calculations of Non-Conventional Fuel Tax Credits for 1990. The inflation adjustment, 1.6730, when applied to the base price of $3/bbl of oil equivalent, adjusts the tax credit to $5.019/bbl for oil and 86.53 cents/MMBTU for gas. The conversion factor for equivalent fuels is 5.8 MMBTU/bbl. Unfortunately, the tax credit for tight formation gas continues to be unadjusted for inflation and remains 52 cents/MMBTU. As many producers are aware, the Omnibus Budget Reconciliation Act of 1990 expanded the dates of eligibility and the usage for-Non-Conventional Fuel Tax Credits. Among other provisions, eligible wells may be placed in service until Jan. 1, 1992, and once in place may utilize the credit for production through Dec. 31, 2002. Both dates are 2 year extensions from previous regulations

Risks and mitigation options for on-site storage of wastewater from shale gas and tight oil development

International Nuclear Information System (INIS)

Kuwayama, Yusuke; Roeshot, Skyler; Krupnick, Alan; Richardson, Nathan; Mares, Jan

2017-01-01

We provide a critical review of existing research and information regarding the sources of risk associated with on-site shale gas and tight oil wastewater storage in the United States, the gaps that exist in knowledge regarding these risks, policy and technology options for addressing the risks, and the relative merits of those options. Specifically, we (a) identify the potential risks to human and ecological health associated with on-site storage of shale gas and tight oil wastewater via a literature survey and analysis of data on wastewater spills and regulatory violations, (b) provide a detailed description of government regulations or industry actions that may mitigate these risks to human and ecological health, and (c) provide a critical review of this information to help generate progress toward concrete action to make shale gas and tight oil development more sustainable and more acceptable to a skeptical public, while keeping costs down. - Highlights: • We review current research/information on shale gas and tight oil wastewater storage. • Pit overflows, tank overfills, and liner malfunctions are common spill causes. • Tanks lead to smaller and less frequent spills than pits, but are not a magic bullet. • State regulations for on-site oil and gas wastewater storage are very heterogeneous.

Study of the sealing performance of tubing adapters in gas-tight deep-sea water sampler

Directory of Open Access Journals (Sweden)

Huang Haocai

2014-09-01

Full Text Available Tubing adapter is a key connection device in Gas-Tight Deep-Sea Water Sampler (GTWS. The sealing performance of the tubing adapter directly affects the GTWS’s overall gas tightness. Tubing adapters with good sealing performance can ensure the transmission of seawater samples without gas leakage and can be repeatedly used. However, the sealing performance of tubing adapters made of different materials was not studied sufficiently. With the research discussed in this paper, the materials match schemes of the tubing adapters were proposed. With non-linear finite element contact analysis and sea trials in the South China Sea, it is expected that the recommended materials match schemes not only meet the requirements of tubing adapters' sealing performance but also provide the feasible options for the following research on tubing adapters in GTWS

Study of the sealing performance of tubing adapters in gas-tight deep-sea water sampler

Directory of Open Access Journals (Sweden)

Haocai Huang

2014-09-01

Full Text Available Tubing adapter is a key connection device in Gas-Tight Deep-Sea Water Sampler (GTWS. The sealing performance of the tubing adapter directly affects the GTWS's overall gas tightness. Tubing adapters with good sealing performance can ensure the transmission of seawater samples without gas leakage and can be repeatedly used. However, the sealing performance of tubing adapters made of different materials was not studied sufficiently. With the research discussed in this paper, the materials match schemes of the tubing adapters were proposed. With non-linear finite element contact analysis and sea trials in the South China Sea, it is expected that the recommended materials match schemes not only meet the requirements of tubing adapters’ sealing performance but also provide the feasible options for the following research on tubing adapters in GTWS.

ADVANCED FRACTURING TECHNOLOGY FOR TIGHT GAS: AN EAST TEXAS FIELD DEMONSTRATION

Energy Technology Data Exchange (ETDEWEB)

Mukul M. Sharma

2005-03-01

The primary objective of this research was to improve completion and fracturing practices in gas reservoirs in marginal plays in the continental United States. The Bossier Play in East Texas, a very active tight gas play, was chosen as the site to develop and test the new strategies for completion and fracturing. Figure 1 provides a general location map for the Dowdy Ranch Field, where the wells involved in this study are located. The Bossier and other tight gas formations in the continental Unites States are marginal plays in that they become uneconomical at gas prices below $2.00 MCF. It was, therefore, imperative that completion and fracturing practices be optimized so that these gas wells remain economically attractive. The economic viability of this play is strongly dependent on the cost and effectiveness of the hydraulic fracturing used in its well completions. Water-fracs consisting of proppant pumped with un-gelled fluid is the type of stimulation used in many low permeability reservoirs in East Texas and throughout the United States. The use of low viscosity Newtonian fluids allows the creation of long narrow fractures in the reservoir, without the excessive height growth that is often seen with cross-linked fluids. These low viscosity fluids have poor proppant transport properties. Pressure transient tests run on several wells that have been water-fractured indicate a long effective fracture length with very low fracture conductivity even when large amounts of proppant are placed in the formation. A modification to the water-frac stimulation design was needed to transport proppant farther out into the fracture. This requires suspending the proppant until the fracture closes without generating excessive fracture height. A review of fracture diagnostic data collected from various wells in different areas (for conventional gel and water-fracs) suggests that effective propped lengths for the fracture treatments are sometimes significantly shorter than those

Genetic Types and Source of the Upper Paleozoic Tight Gas in the Hangjinqi Area, Northern Ordos Basin, China

Directory of Open Access Journals (Sweden)

Xiaoqi Wu

2017-01-01

Full Text Available The molecular and stable isotopic compositions of the Upper Paleozoic tight gas in the Hangjinqi area in northern Ordos Basin were investigated to study the geochemical characteristics. The tight gas is mainly wet with the dryness coefficient (C1/C1–5 of 0.853–0.951, and δ13C1 and δ2H-C1 values are ranging from -36.2‰ to -32.0‰ and from -199‰ to -174‰, respectively, with generally positive carbon and hydrogen isotopic series. Identification of gas origin indicates that tight gas is mainly coal-type gas, and it has been affected by mixing of oil-type gas in the wells from the Shilijiahan and Gongkahan zones adjacent to the Wulanjilinmiao and Borjianghaizi faults. Gas-source correlation indicates that coal-type gas in the Shiguhao zone displays distal-source accumulation. It was mainly derived from the coal-measure source rocks in the Upper Carboniferous Taiyuan Formation (C3t and Lower Permian Shanxi Formation (P1s, probably with a minor contribution from P1s coal measures from in situ Shiguhao zone. Natural gas in the Shilijiahan and Gongkahan zones mainly displays near-source accumulation. The coal-type gas component was derived from in situ C3t-P1s source rocks, whereas the oil-type gas component might be derived from the carbonate rocks in the Lower Ordovician Majiagou Formation (O1m.

Simulation of a multistage fractured horizontal well in a water-bearing tight fractured gas reservoir under non-Darcy flow

Science.gov (United States)

Zhang, Rui-Han; Zhang, Lie-Hui; Wang, Rui-He; Zhao, Yu-Long; Huang, Rui

2018-06-01

Reservoir development for unconventional resources such as tight gas reservoirs is in increasing demand due to the rapid decline of production in conventional reserves. Compared with conventional reservoirs, fluid flow in water-bearing tight gas reservoirs is subject to more nonlinear multiphase flow and gas slippage in nano/micro matrix pores because of the strong collisions between rock and gas molecules. Economic gas production from tight gas reservoirs depends on extensive application of water-based hydraulic fracturing of horizontal wells, associated with non-Darcy flow at a high flow rate, geomechanical stress sensitivity of un-propped natural fractures, complex flow geometry and multiscale heterogeneity. How to efficiently and accurately predict the production performance of a multistage fractured horizontal well (MFHW) is challenging. In this paper, a novel multicontinuum, multimechanism, two-phase simulator is established based on unstructured meshes and the control volume finite element method to analyze the production performance of MFHWs. The multiple interacting continua model and discrete fracture model are coupled to integrate the unstimulated fractured reservoir, induced fracture networks (stimulated reservoir volumes, SRVs) and irregular discrete hydraulic fractures. Several simulations and sensitivity analyses are performed with the developed simulator for determining the key factors affecting the production performance of MFHWs. Two widely applied fracturing models, classic hydraulic fracturing which generates long double-wing fractures and the volumetric fracturing aimed at creating large SRVs, are compared to identify which of them can make better use of tight gas reserves.

PP and PS seismic response from fractured tight gas reservoirs: a case study

International Nuclear Information System (INIS)

Jianming, Tang; Shaonan, Zhang; Li, Xiang-Yang

2008-01-01

In this paper, we present an example of using PP and PS converted-wave data recorded by digital micro-eletro-mechanical-systems (MEMS) to evaluate a fractured tight gas reservoir from the Xinchang gas field in Sichuan, China. For this, we analyse the variations in converted shear-wave splitting, Vp/Vs ratio and PP and PS impedance, as well as other attributes based on absorption and velocity dispersion. The reservoir formation is tight sandstone, buried at a depth of about 5000 m, and the converted-wave data reveal significant shear-wave splitting over the reservoir formation. We utilize a rotation technique to extract the shear-wave polarization and time delay from the data, and a small-window correlation method to build time-delay spectra that allow the generation of a time-delay section. At the reservoir formation, the shear-wave time delay is measured at 20 ms, about 15% shear-wave anisotropy, correlating with the known gas reservoirs. Furthermore, the splitting anomalies are consistent with the characteristics of other attributes such as Vp/Vs ratio and P- and S-wave acoustic and elastic impedance. The P-wave shows consistent low impedance over the reservoir formation, whilst the S-wave impedance shows relatively high impedance. The calculated gas indicator based on absorption and velocity dispersion yields a high correlation with the gas bearing formations. This confirms the benefit of multicomponent seismic data from digital MEMS sensors

Statistical methods to monitor the West Valley off-gas system

International Nuclear Information System (INIS)

Eggett, D.L.

1990-01-01

This paper reports on the of-gas system for the ceramic melter operated at the West Valley Demonstration Project at West Valley, NY, monitored during melter operation. A one-at-a-time method of monitoring the parameters of the off-gas system is not statistically sound. Therefore, multivariate statistical methods appropriate for the monitoring of many correlated parameters will be used. Monitoring a large number of parameters increases the probability of a false out-of-control signal. If the parameters being monitored are statistically independent, the control limits can be easily adjusted to obtain the desired probability of a false out-of-control signal. The principal component (PC) scores have desirable statistical properties when the original variables are distributed as multivariate normals. Two statistics derived from the PC scores and used to form multivariate control charts are outlined and their distributional properties reviewed

Integration of seismic data and a triple porosity model for interpretation of tight gas formations in the Western Canada sedimentary basin

Energy Technology Data Exchange (ETDEWEB)

Castillo, Fernando; Aguilera, Roberto; Lawton, Don [University of Calgary (Canada)

2011-07-01

Due to the increased global demand for oil and gas, companies are looking to unconventional methods for exploring, drilling and refining these products. Unconventional reservoirs are found in the form of shale gas, coal bed methane and tight gas. This paper presents a model for evaluating various tight gas reservoirs in the Western Canada sedimentary basin (WCSB) by developing an equation. The proposed method integrates a triple porosity model with sonic, density and resistivity logs. The model uses petrographic data from work in the WCSB to determine the types of pores that are present in the tight rocks. The process also provides information on inter-well formation resistivity, porosity and water saturation to allow estimation of the amount of original gas in place. The results calculated from this study agreed with the actual deep resistivities of the WCSB Nikanassin group. This model can also be applied to other regions of the world that have similar characteristics to those of the WCSB.

The tightness of the globe valves in the exploitations practice of the gas pipe-lines

International Nuclear Information System (INIS)

Pietrak, T.; Rudzki, Z.; Surmacz, W.

2006-01-01

Technological units of the Transit Gas Pipeline (i.e. Compressor Stations, Valve Stations, Stations or National Network Service Installations) have been fitted with Ball Valves as shut-off devices (block valves). Internal tightness of the valves' seat becomes major factor in securing proper service conditions during normal pipeline operation as well as for isolating of pipeline sections in emergency situations (loss of pipeline integrity or uncontrolled gas escape). Internal tightness of the valves is being inspected during scheduled maintenance of the pipeline units. Any leak revealed during inspection is being repaired, following instructions provided in the Manufacturer's Valve Manual. After a time, some cases have been identified, when repair of the revealed leak was found to be difficult, despite close following of the repair manuals. The paper presents analysis of the issue and corrective actions taken accordingly. (authors)

Characterizing tight-gas systems with production data: Wyoming, Utah, and Colorado

Science.gov (United States)

Nelson, Philip H.; Santus, Stephen L.; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

2013-01-01

The study of produced fluids allows comparisons among tight-gas systems. This paper examines gas, oil, and water production data from vertical wells in 23 fields in five Rocky Mountain basins of the United States, mostly from wells completed before the year 2000. Average daily rates of gas, oil, and water production are determined two years and seven years after production begins in order to represent the interval in which gas production declines exponentially. In addition to the daily rates, results are also presented in terms of oil-to-gas and water-to-gas ratios, and in terms of the five-year decline in gas production rates and water-to-gas ratios. No attempt has been made to estimate the ultimate productivity of wells or fields. The ratio of gas production rates after seven years to gas production rates at two years is about one-half, with median ratios falling within a range of 0.4 to 0.6 in 16 fields. Oil-gas ratios show substantial variation among fields, ranging from dry gas (no oil) to wet gas to retrograde conditions. Among wells within fields, the oil-gas ratios vary by a factor of three to thirty, with the exception of the Lance Formation in Jonah and Pinedale fields, where the oil-gas ratios vary by less than a factor of two. One field produces water-free gas and a large fraction of wells in two other fields produce water-free gas, but most fields have water-gas ratios greater than 1 bbl/mmcf—greater than can be attributed to water dissolved in gas in the reservoir— and as high as 100 bbl/mmcf. The median water-gas ratio for fields increases moderately with time, but in individual wells water influx relative to gas is erratic, increasing greatly with time in many wells while remaining constant or decreasing in others.

Structural-Diagenetic Controls on Fracture Opening in Tight Gas Sandstone Reservoirs, Alberta Foothills

Science.gov (United States)

Ukar, Estibalitz; Eichhubl, Peter; Fall, Andras; Hooker, John

2013-04-01

In tight gas reservoirs, understanding the characteristics, orientation and distribution of natural open fractures, and how these relate to the structural and stratigraphic setting are important for exploration and production. Outcrops provide the opportunity to sample fracture characteristics that would otherwise be unknown due to the limitations of sampling by cores and well logs. However, fractures in exhumed outcrops may not be representative of fractures in the reservoir because of differences in burial and exhumation history. Appropriate outcrop analogs of producing reservoirs with comparable geologic history, structural setting, fracture networks, and diagenetic attributes are desirable but rare. The Jurassic to Lower Cretaceous Nikanassin Formation from the Alberta Foothills produces gas at commercial rates where it contains a network of open fractures. Fractures from outcrops have the same diagenetic attributes as those observed in cores fractures relative to fold cores, hinges and limbs, 2) compare the distribution and attributes of fractures in outcrop vs. core samples, 3) estimate the timing of fracture formation relative to the evolution of the fold-and-thrust belt, and 4) estimate the degradation of fracture porosity due to postkinematic cementation. Cathodoluminescence images of cemented fractures in both outcrop and core samples reveal several generations of quartz and ankerite cement that is synkinematic and postkinematic relative to fracture opening. Crack-seal textures in synkinematic quartz are ubiquitous, and well-developed cement bridges abundant. Fracture porosity may be preserved in fractures wider than ~100 microns. 1-D scanlines in outcrop and core samples indicate fractures are most abundant within small parasitic folds within larger, tight, mesoscopic folds. Fracture intensity is lower away from parasitic folds; intensity progressively decreases from the faulted cores of mesoscopic folds to their forelimbs, with lowest intensities within

Investigation of hydraulic fracture re-orientation effects in tight gas reservoirs

Energy Technology Data Exchange (ETDEWEB)

Hagemann, B.; Wegner, J.; Ganzer, L. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE

2013-08-01

In tight gas formations where the low matrix permeability prevents successful and economic production rates, hydraulic fracturing is required to produce a well at economic rates. The initial fracture opens in the direction of minimum stress and propagates into the direction of maximum stress. As production from the well and its initial fracture declines, re-fracturing treatments are required to accelerate recovery. The orientation of the following hydraulic fracture depends on the actual stress-state of the formation in the vicinity of the wellbore. Previous investigations by Elbel and Mack (1993) demonstrated that the stress alters during depletion and a stress reversal region appears. This behavior causes a different fracture orientation of the re-fracturing operation. For the investigation of re-fracture orientation a two-dimensional reservoir model has been designed using COMSOL Multiphysics. The model represents a fractured vertical well in a tight gas reservoir of infinite thickness. A time dependent study was set up to simulate the reservoir depletion by the production from the fractured well. The theory of poroelasticity was used to couple the fluid flow and geo-mechanical behavior. The stress state is initially defined as uniform and the attention is concentrated to the alteration of stress due to the lowered pore pressure. Different cases with anisotropic and heterogeneous permeability are set up to determine its significance. The simulation shows that an elliptical shaped drainage area appears around the fracture. The poroelastic behavior effects that the stress re-orientates and a stress reversal region originates, if the difference between minimum and maximum horizontal stresses is small. The consideration of time indicates that the dimension of the region initially extends fast until it reaches its maximum. Subsequently, the stress reversal region's extent shrinks slowly until it finally disappears. The reservoir characteristics, e.g. the

Enhanced Recovery in Tight Gas Reservoirs using Maxwell-Stefan Equations

Science.gov (United States)

Santiago, C. J. S.; Kantzas, A.

2017-12-01

Due to the steep production decline in unconventional gas reservoirs, enhanced recovery (ER) methods are receiving great attention from the industry. Wet gas or liquid rich reservoirs are the preferred ER candidates due to higher added value from natural gas liquids (NGL) production. ER in these reservoirs has the potential to add reserves by improving desorption and displacement of hydrocarbons through the medium. Nevertheless, analysis of gas transport at length scales of tight reservoirs is complicated because concomitant mechanisms are in place as pressure declines. In addition to viscous and Knudsen diffusion, multicomponent gas modeling includes competitive adsorption and molecular diffusion effects. Most models developed to address these mechanisms involve single component or binary mixtures. In this study, ER by gas injection is investigated in multicomponent (C1, C2, C3 and C4+, CO2 and N2) wet gas reservoirs. The competing effects of Knudsen and molecular diffusion are incorporated by using Maxwell-Stefan equations and the Dusty-Gas approach. This model was selected due to its superior properties on representing the physics of multicomponent gas flow, as demonstrated during the presented model validation. Sensitivity studies to evaluate adsorption, reservoir permeability and gas type effects are performed. The importance of competitive adsorption on production and displacement times is demonstrated. In the absence of adsorption, chromatographic separation is negligible. Production is merely dictated by competing effects between molecular and Knudsen diffusion. Displacement fronts travel rapidly across the medium. When adsorption effects are included, molecules with lower affinity to the adsorption sites will be produced faster. If the injected gas is inert (N2), an increase in heavier fraction composition occurs in the medium. During injection of adsorbing gases (CH4 and CO2), competitive adsorption effects will contribute to improved recovery of heavier

Thermophysical instruments for non-destructive examination of tightness and internal gas pressure or irradiated power reactor fuel rods

International Nuclear Information System (INIS)

Pastoushin, V.V.; Novikov, A.Yu.; Bibilashvili, Yu.K.

1998-01-01

The developed thermophysical method and technical instruments for non-destructive leak-tightness and gas pressure inspection inside irradiated power reactor fuel rods and FAs under poolside and hot cell conditions are described. The method of gas pressure measuring based on the examination of parameters of thermal convection that aroused in gas volume of rod plenum by special technical instruments. The developed method and technique allows accurate value determination of not only one of the main critical rod parameters, namely total internal gas pressure, that forms rod mean life in the reactor core, but also the partial pressure of every main constituent of gaseous mixture inside irradiated fuel rod, that provides the feasibility of authentic and reliable leak-tightness detection. The described techniques were experimentally checked during the examination of all types power reactor fuel rods existing in Russia (WWER, BN, RBMK) and could form the basis for new technique development for non-destructive examination of PWR (and other) type rods and FAs having gas plenum filled with spring or another elements of design. (author)

An unconventional rate decline approach for tight and fracture-dominated gas wells

Energy Technology Data Exchange (ETDEWEB)

Duong, A.N. [ConocoPhillips Canada Resources Corp., Calgary, AB (Canada)

2010-07-01

In both Canada and the United States, unconventional gas reservoirs, especially wet shale gas are being aggressively pursued for new development. Forecasting production and estimating reserves accurately for these resource plays has become increasingly important and necessary. This paper introduced an empirically derived decline model based on a long-term linear flow in a large number of wells in tight and shale gas reservoirs. A new methodology was developed for production analysis and forecasting of unconventional reservoirs based on this model. In order to represent any uncertainty in reserve estimation, this method also utilized probability distributions of reserves in forecasting resource plays. The paper discussed the methodology development including long-term linear flow and their associated equations, as well as several field examples including a gas retrograde case and individual well analysis. Result comparisons and a discussion of the results were also presented. It was concluded that pressure initialization used in numerical modeling based on fluid gradients may have been incorrect. Results from such numerical modeling may not be representative of the shale gas flow characteristics. 24 refs., 2 tabs., 15 figs., 1 appendix.

The RealGas and RealGasH2O Options of the TOUGH+ Code for the Simulation of Coupled Fluid and Heat Flow in Tight/Shale Gas Systems

Energy Technology Data Exchange (ETDEWEB)

Moridis, George; Freeman, Craig

2013-09-30

We developed two new EOS additions to the TOUGH+ family of codes, the RealGasH2O and RealGas . The RealGasH2O EOS option describes the non-isothermal two-phase flow of water and a real gas mixture in gas reservoirs, with a particular focus in ultra-tight (such as tight-sand and shale gas) reservoirs. The gas mixture is treated as either a single-pseudo-component having a fixed composition, or as a multicomponent system composed of up to 9 individual real gases. The RealGas option has the same general capabilities, but does not include water, thus describing a single-phase, dry-gas system. In addition to the standard capabilities of all members of the TOUGH+ family of codes (fully-implicit, compositional simulators using both structured and unstructured grids), the capabilities of the two codes include: coupled flow and thermal effects in porous and/or fractured media, real gas behavior, inertial (Klinkenberg) effects, full micro-flow treatment, Darcy and non-Darcy flow through the matrix and fractures of fractured media, single- and multi-component gas sorption onto the grains of the porous media following several isotherm options, discrete and fracture representation, complex matrix-fracture relationships, and porosity-permeability dependence on pressure changes. The two options allow the study of flow and transport of fluids and heat over a wide range of time frames and spatial scales not only in gas reservoirs, but also in problems of geologic storage of greenhouse gas mixtures, and of geothermal reservoirs with multi-component condensable (H2O and CH4) and non-condensable gas mixtures. The codes are verified against available analytical and semi-analytical solutions. Their capabilities are demonstrated in a series of problems of increasing complexity, ranging from isothermal flow in simpler 1D and 2D conventional gas reservoirs, to non-isothermal gas flow in 3D fractured shale gas reservoirs involving 4 types of fractures, micro-flow, non-Darcy flow and gas

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.

GPU-Based Computation of Formation Pressure for Multistage Hydraulically Fractured Horizontal Wells in Tight Oil and Gas Reservoirs

Directory of Open Access Journals (Sweden)

Rongwang Yin

2018-01-01

Full Text Available A mathematical model for multistage hydraulically fractured horizontal wells (MFHWs in tight oil and gas reservoirs was derived by considering the variations in the permeability and porosity of tight oil and gas reservoirs that depend on formation pressure and mixed fluid properties and introducing the pseudo-pressure; analytical solutions were presented using the Newman superposition principle. The CPU-GPU asynchronous computing model was designed based on the CUDA platform, and the analytic solution was decomposed into infinite summation and integral forms for parallel computation. Implementation of this algorithm on an Intel i5 4590 CPU and NVIDIA GT 730 GPU demonstrates that computation speed increased by almost 80 times, which meets the requirement for real-time calculation of the formation pressure of MFHWs.

Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface ground water: background, base cases, shallow reservoirs, short-term gas and water transport

Science.gov (United States)

Researchers examined gas and water transport between a deep tight shale gas reservoir and a shallow overlying aquifer in the two years following hydraulic fracturing, assuming a pre-existing connecting pathway.

A new method in predicting productivity of multi-stage fractured horizontal well in tight gas reservoirs

Directory of Open Access Journals (Sweden)

Yunsheng Wei

2016-10-01

Full Text Available The generally accomplished technique for horizontal wells in tight gas reservoirs is by multi-stage hydraulic fracturing, not to mention, the flow characteristics of a horizontal well with multiple transverse fractures are very intricate. Conventional methods, well as an evaluation unit, are difficult to accurately predict production capacity of each fracture and productivity differences between wells with a different number of fractures. Thus, a single fracture sets the minimum evaluation unit, matrix, fractures, and lateral wellbore model that are then combined integrally to approximate horizontal well with multiple transverse hydraulic fractures in tight gas reservoirs. This paper presents a new semi-analytical methodology for predicting the production capacity of a horizontal well with multiple transverse hydraulic fractures in tight gas reservoirs. Firstly, a mathematical flow model used as a medium, which is disturbed by finite conductivity vertical fractures and rectangular shaped boundaries, is established and explained by the Fourier integral transform. Then the idea of a single stage fracture analysis is incorporated to establish linear flow model within a single fracture with a variable rate. The Fredholm integral numerical solution is applicable for the fracture conductivity function. Finally, the pipe flow model along the lateral wellbore is adapted to couple multi-stages fracture mathematical models, and the equation group of predicting productivity of a multi-stage fractured horizontal well. The whole flow process from the matrix to bottom-hole and production interference between adjacent fractures is also established. Meanwhile, the corresponding iterative algorithm of the equations is given. In this case analysis, the productions of each well and fracture are calculated under the different bottom-hole flowing pressure, and this method also contributes to obtaining the distribution of pressure drop and production for every

Contraption and Prediction of Exhalation Tight Brownstone in Exhalation Cistern

OpenAIRE

XhingZhiwang, -; Xuchao, -

2012-01-01

The reservoir connate water saturation is high and gas wells generally produce water which seriously affects the productivity of gas wells in Xujiahe tight sandstone gas reservoirs in Sichuan Basin. Take the sixth formation for example, there are 39 wells producing water unequally in the 42 commissioning wells, and the excessive water production leads to the production of the gas well declining rapidly. Studying of the mechanism of water production in tight sandstone gas reservoirs and predic...

Band nesting, massive Dirac fermions, and valley Landé and Zeeman effects in transition metal dichalcogenides: A tight-binding model

Science.gov (United States)

Bieniek, Maciej; Korkusiński, Marek; Szulakowska, Ludmiła; Potasz, Paweł; Ozfidan, Isil; Hawrylak, Paweł

2018-02-01

We present here the minimal tight-binding model for a single layer of transition metal dichalcogenides (TMDCs) MX 2(M , metal; X , chalcogen) which illuminates the physics and captures band nesting, massive Dirac fermions, and valley Landé and Zeeman magnetic field effects. TMDCs share the hexagonal lattice with graphene but their electronic bands require much more complex atomic orbitals. Using symmetry arguments, a minimal basis consisting of three metal d orbitals and three chalcogen dimer p orbitals is constructed. The tunneling matrix elements between nearest-neighbor metal and chalcogen orbitals are explicitly derived at K ,-K , and Γ points of the Brillouin zone. The nearest-neighbor tunneling matrix elements connect specific metal and sulfur orbitals yielding an effective 6 ×6 Hamiltonian giving correct composition of metal and chalcogen orbitals but not the direct gap at K points. The direct gap at K , correct masses, and conduction band minima at Q points responsible for band nesting are obtained by inclusion of next-neighbor Mo-Mo tunneling. The parameters of the next-nearest-neighbor model are successfully fitted to MX 2(M =Mo ; X =S ) density functional ab initio calculations of the highest valence and lowest conduction band dispersion along K -Γ line in the Brillouin zone. The effective two-band massive Dirac Hamiltonian for MoS2, Landé g factors, and valley Zeeman splitting are obtained.

Design philosophy and practice of asymmetrical 3D fracturing and random fracturing: A case study of tight sand gas reservoirs in western Sichuan Basin

Directory of Open Access Journals (Sweden)

Jianchun Guo

2015-03-01

Full Text Available At present two technical models are commonly taken in tight gas reservoir stimulation: conventional massive fracturing and SRV fracturing, but how to select a suitable fracturing model suitable for reservoir characteristics is still a question waiting to be answered. In this paper, based on the analysis of geological characteristics and seepage mechanism of tight gas and shale gas reservoirs, the differences between stimulation philosophy of tight gas reservoirs and shale reservoirs are elucidated, and the concept that a suitable stimulation model should be selected based on reservoir geological characteristics and seepage mechanism aiming at maximally improving the seepage capability of a reservoir. Based on this concept, two fracturing design methods were proposed for two tight gas reservoirs in western Sichuan Basin: asymmetrical 3D fracturing design (A3DF for the middle-shallow Upper Jurassic Penglaizhen Fm stacked reservoirs in which the hydraulic fractures can well match the sand spatial distribution and seepage capability of the reservoirs; SRV fracturing design which can increase fracture randomness in the sandstone and shale laminated reservoirs for the 5th Member of middle-deep Upper Triassic Xujiahe Fm. Compared with that by conventional fracturing, the average production of horizontal wells fractured by A3DF increased by 41%, indicating that A3DF is appropriate for gas reservoir development in the Penglaizhen Fm; meanwhile, the average production per well of the 5th Member of the Xujiahe Fm was 2.25 × 104 m3/d after SRV fracturing, showing that the SRV fracturing is a robust technical means for the development of this reservoir.

The integrated melter off-gas treatment systems at the West Valley Demonstration Project

Energy Technology Data Exchange (ETDEWEB)

Vance, R.F. [West Valley Nuclear Services Co., Inc., NY (United States)

1995-02-01

The West Valley Demonstration Project was established by Public Law 96-368, the {open_quotes}West Valley Demonstration Project Act, {close_quotes} on October 1, l980. Under this act, Congress directed the Department of Energy to carry out a high level radioactive waste management demonstration project at the Western New York Nuclear Service Center in West Valley, New York. The purpose of this project is to demonstrate solidification techniques which can be used for preparing high level radioactive waste for disposal. In addition to developing this technology, the West Valley Demonstration Project Act directs the Department of Energy to: (1) develop containers suitable for permanent disposal of the high level waste; (2) transport the solidified high level waste to a Federal repository; (3) dispose of low level and transuranic waste produced under the project; and (4) decontaminate and decommission the facilities and materials associated with project activities and the storage tanks originally used to store the liquid high level radioactive waste. The process of vitrification will be used to solidify the high level radioactive liquid wastes into borosilicate glass. This report describes the functions, the controlling design criteria, and the resulting design of the melter off-gas treatment systems which are used in the vitrification process.

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

Naturally fractured tight gas: Gas reservoir detection optimization. Quarterly report, January 1--March 31, 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

Economically viable natural gas production from the low permeability Mesaverde Formation in the Piceance Basin, Colorado requires the presence of an intense set of open natural fractures. Establishing the regional presence and specific location of such natural fractures is the highest priority exploration goal in the Piceance and other western US tight, gas-centered basins. Recently, Advanced Resources International, Inc. (ARI) completed a field program at Rulison Field, Piceance Basin, to test and demonstrate the use of advanced seismic methods to locate and characterize natural fractures. This project began with a comprehensive review of the tectonic history, state of stress and fracture genesis of the basin. A high resolution aeromagnetic survey, interpreted satellite and SLAR imagery, and 400 line miles of 2-D seismic provided the foundation for the structural interpretation. The central feature of the program was the 4.5 square mile multi-azimuth 3-D seismic P-wave survey to locate natural fracture anomalies. The interpreted seismic attributes are being tested against a control data set of 27 wells. Additional wells are currently being drilled at Rulison, on close 40 acre spacings, to establish the productivity from the seismically observed fracture anomalies. A similar regional prospecting and seismic program is being considered for another part of the basin. The preliminary results indicate that detailed mapping of fault geometries and use of azimuthally defined seismic attributes exhibit close correlation with high productivity gas wells. The performance of the ten new wells, being drilled in the seismic grid in late 1996 and early 1997, will help demonstrate the reliability of this natural fracture detection and mapping technology.

The integrated melter off-gas treatment systems at the West Valley Demonstration Project

International Nuclear Information System (INIS)

Vance, R.F.

1991-12-01

The West Valley Demonstration project was established by an act of Congress in 1980 to solidify the high level radioactive liquid wastes produced from operation of the Western New York Nuclear Services Center from 1966 to 1972. The waste will be solidified as borosilicate glass. This report describes the functions, the controlling design criteria, and the resulting design of the melter off-gas treatment systems

Appraisal of the tight sands potential of the Sand Wash and Great Divide Basins

International Nuclear Information System (INIS)

1993-08-01

The volume of future tight gas reserve additions is difficult to estimate because of uncertainties in the characterization and extent of the resource and the performance and cost-effectiveness of stimulation and production technologies. Ongoing R ampersand D by industry and government aims to reduce the risks and costs of producing these tight resources, increase the certainty of knowledge of their geologic characteristics and extent, and increase the efficiency of production technologies. Some basins expected to contain large volumes of tight gas are being evaluated as to their potential contribution to domestic gas supplies. This report describes the results of one such appraisal. This analysis addresses the tight portions of the Eastern Greater Green River Basin (Sand Wash and Great Divide Subbasins in Northwestern Colorado and Southwestern Wyoming, respectively), with respect to estimated gas-in-place, technical recovery, and potential reserves. Geological data were compiled from public and proprietary sources. The study estimated gas-in-place in significant (greater than 10 feet net sand thickness) tight sand intervals for six distinct vertical and 21 areal units of analysis. These units of analysis represent tight gas potential outside current areas of development. For each unit of analysis, a ''typical'' well was modeled to represent the costs, recovery and economics of near-term drilling prospects in that unit. Technically recoverable gas was calculated using reservoir properties and assumptions about current formation evaluation and extraction technology performance. Basin-specific capital and operating costs were incorporated along with taxes, royalties and current regulations to estimate the minimum required wellhead gas price required to make the typical well in each of unit of analysis economic

Coherent soft X-ray high-order harmonics using tight-focusing laser pulses in the gas mixture.

Science.gov (United States)

Lu, Faming; Xia, Yuanqin; Zhang, Sheng; Chen, Deying; Zhao, Yang; Liu, Bin

2014-01-01

We experimentally study the harmonics from a Xe-He gas mixture using tight-focusing femtosecond laser pulses. The spectrum in the mixed gases exhibits an extended cutoff region from the harmonic H21 to H27. The potential explanation is that the harmonics photons from Xe contribute the electrons of He atoms to transmit into the excited-state. Therefore, the harmonics are emitted from He atoms easily. Furthermore, we show that there are the suppressed harmonics H15 and H17 in the mixed gases. The underlying mechanism is the destructive interference between harmonics generated from different atoms. Our results indicate that HHG from Xe-He gas mixture is an efficient method of obtaining the coherent soft X-ray source.

Valley qubit in a gated MoS2 monolayer quantum dot

Science.gov (United States)

Pawłowski, J.; Żebrowski, D.; Bednarek, S.

2018-04-01

The aim of the presented research is to design a nanodevice, based on a MoS2 monolayer, performing operations on a well-defined valley qubit. We show how to confine an electron in a gate-induced quantum dot within the monolayer, and to perform the not operation on its valley degree of freedom. The operations are carried out all electrically via modulation of the confinement potential by oscillating voltages applied to the local gates. Such quantum dot structure is modeled realistically. Through these simulations we investigate the possibility of realization of a valley qubit in analogy with a realization of the spin qubit. We accurately model the potential inside the nanodevice accounting for proper boundary conditions on the gates and space-dependent materials permittivity by solving the generalized Poisson's equation. The time evolution of the system is supported by realistic self-consistent Poisson-Schrödinger tight-binding calculations. The tight-binding calculations are further confirmed by simulations within the effective continuum model.

Numerical simulation of the environmental impact of hydraulic fracturing of tight/shale gas reservoirs on near-surface groundwater: Background, base cases, shallow reservoirs, short-term gas, and water transport

Science.gov (United States)

Reagan, Matthew T; Moridis, George J; Keen, Noel D; Johnson, Jeffrey N

2015-01-01

Hydrocarbon production from unconventional resources and the use of reservoir stimulation techniques, such as hydraulic fracturing, has grown explosively over the last decade. However, concerns have arisen that reservoir stimulation creates significant environmental threats through the creation of permeable pathways connecting the stimulated reservoir with shallower freshwater aquifers, thus resulting in the contamination of potable groundwater by escaping hydrocarbons or other reservoir fluids. This study investigates, by numerical simulation, gas and water transport between a shallow tight-gas reservoir and a shallower overlying freshwater aquifer following hydraulic fracturing operations, if such a connecting pathway has been created. We focus on two general failure scenarios: (1) communication between the reservoir and aquifer via a connecting fracture or fault and (2) communication via a deteriorated, preexisting nearby well. We conclude that the key factors driving short-term transport of gas include high permeability for the connecting pathway and the overall volume of the connecting feature. Production from the reservoir is likely to mitigate release through reduction of available free gas and lowering of reservoir pressure, and not producing may increase the potential for release. We also find that hydrostatic tight-gas reservoirs are unlikely to act as a continuing source of migrating gas, as gas contained within the newly formed hydraulic fracture is the primary source for potential contamination. Such incidents of gas escape are likely to be limited in duration and scope for hydrostatic reservoirs. Reliable field and laboratory data must be acquired to constrain the factors and determine the likelihood of these outcomes. Key Points: Short-term leakage fractured reservoirs requires high-permeability pathways Production strategy affects the likelihood and magnitude of gas release Gas release is likely short-term, without additional driving forces PMID

Investigation of gas molecules adsorption on carbon nano tubes electric properties in tight binding model

International Nuclear Information System (INIS)

Moradian, R.; Mohammadi, Y.

2007-01-01

Based on tight binding model we investigated effects of bi-atomic molecules gas(in the general form denoted by X 2 )on single-walled carbon nano tubes electronic properties. We found for some specified values of hopping integrals and random on-site energies, adsorbed molecules bound states located inside of the (10,0) single-walled carbon nano tubes energy gap, where it is similar to the reported experimental results for O 2 adsorption while for other values there is no bound states inside of energy gap. This is similar to the N 2 adsorption on semiconductor single-walled carbon nano tubes.

Design of the ATLAS New Small Wheel Gas Leak Tightness Station for the Micromegas Detector Modules

CERN Document Server

Gazis, Evangelos; The ATLAS collaboration

2017-01-01

In this work we describe advanced data processing and analysis techniques intended to be used in the gas tightness station at CERN for Quality Assurance and Quality Control of the New Small Wheel Micromegas Quadruplets. We combine two methods: a conventional one based on the Pressure Decay Rate and an alternative-novel one, based on the Flow Rate Loss. A prototype setup has been developed based on a Lock-in Amplifier device and should be operated in conjunction with the gas leak test via the Flow Rate Loss. Both methods have been tested by using emulated leak branches based on specific thin medical needles. The semi-automatic data acquisition, monitoring and processing system is presented also in this work while a more sophisticated environment based on the WinCC-OA SCADA is under development.

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

Damage evaluation on oil-based drill-in fluids for ultra-deep fractured tight sandstone gas reservoirs

Directory of Open Access Journals (Sweden)

Jinzhi Zhu

2017-07-01

Full Text Available In order to explore the damage mechanisms and improve the method to evaluate and optimize the performance of formation damage control of oil-based drill-in fluids, this paper took an ultra-deep fractured tight gas reservoir in piedmont configuration, located in the Cretaceous Bashijiqike Fm of the Tarim Basin, as an example. First, evaluation experiments were conducted on the filtrate invasion, the dynamic damage of oil-based drill-in fluids and the loading capacity of filter cakes. Meanwhile, the evaluating methods were optimized for the formation damage control effect of oil-based drill-in fluids in laboratory: pre-processing drill-in fluids before grading analysis; using the dynamic damage method to simulate the damage process for evaluating the percentage of regained permeability; and evaluating the loading capacity of filter cakes. The experimental results show that (1 oil phase trapping damage and solid phase invasion are the main formation damage types; (2 the damage degree of filtrate is the strongest on the matrix; and (3 the dynamic damage degree of oil-based drill-in fluids reaches medium strong to strong on fractures and filter cakes show a good sealing capacity for the fractures less than 100 μm. In conclusion, the filter cakes' loading capacity should be first guaranteed, and both percentage of regained permeability and liquid trapping damage degree should be both considered in the oil-based drill-in fluids prepared for those ultra-deep fractured tight sandstone gas reservoirs.

Origin of salinity in produced waters from the Palm Valley gas field, Northern Territory, Australia

International Nuclear Information System (INIS)

Andrew, Anita S.; Whitford, David J.; Berry, Martin D.; Barclay, Stuart A.; Giblin, Angela M.

2005-01-01

The chemical composition and evolution of produced waters associated with gas production in the Palm Valley gas field, Northern Territory, has important implications for issues such as gas reserve calculations, reservoir management and saline water disposal. The occurrence of saline formation water in the Palm Valley field has been the subject of considerable debate. There were no occurrences of mobile water early in the development of the field and only after gas production had reduced the reservoir pressure, was saline formation water produced. Initially this was in small quantities but has increased dramatically with time, particularly after the initiation of compression in November 1996. The produced waters range from highly saline (up to 300,000 mg/L TDS), with unusual enrichments in Ca, Ba and Sr, to low salinity fluids that may represent condensate waters. The Sr isotopic compositions of the waters ( 87 Sr/ 86 Sr = 0.7041-0.7172) are also variable but do not correlate closely with major and trace element abundances. Although the extreme salinity suggests possible involvement of evaporite deposits lower in the stratigraphic sequence, the Sr isotopic composition of the high salinity waters suggests a more complex evolutionary history. The formation waters are chemically and isotopically heterogeneous and are not well mixed. The high salinity brines have Sr isotopic compositions and other geochemical characteristics more consistent with long-term residence within the reservoir rocks than with present-day derivation from a more distal pool of brines associated with evaporites. If the high salinity brines entered the reservoir during the Devonian uplift and were displaced by the reservoir gas into a stagnant pool, which has remained near the reservoir for the last 300-400 Ma, then the size of the brine pool is limited. At a minimum, it might be equivalent to the volume displaced by the reservoired gas

Design and Implementation of Energized Fracture Treatment in Tight Gas Sands

Energy Technology Data Exchange (ETDEWEB)

Mukul Sharma; Kyle Friehauf

2009-12-31

, the minimum CO{sub 2} gas quality (volume % of gas) recommended is 30% for moderate differences between fracture and reservoir pressures (2900 psi reservoir, 5300 psi fracture). The minimum quality is reduced to 20% when the difference between pressures is larger, resulting in additional gas expansion in the invaded zone. Inlet fluid temperature, flow rate, and base viscosity did not have a large impact on fracture production. Finally, every stage of the fracturing treatment should be energized with a gas component to ensure high gas saturation in the invaded zone. A second, more general, sensitivity study was conducted. Simulations show that CO{sub 2} outperforms N{sub 2} as a fluid component because it has higher solubility in water at fracturing temperatures and pressures. In fact, all gas components with higher solubility in water will increase the fluid's ability to reduce damage in the invaded zone. Adding methanol to the fracturing solution can increase the solubility of CO{sub 2}. N{sub 2} should only be used if the gas leaks-off either during the creation of the fracture or during closure, resulting in gas going into the invaded zone. Experimental data is needed to determine if the gas phase leaks-off during the creation of the fracture. Simulations show that the bubbles in a fluid traveling across the face of a porous medium are not likely to attach to the surface of the rock, the filter cake, or penetrate far into the porous medium. In summary, this research has created the first compositional fracturing simulator, a useful tool to aid in energized fracture design. We have made several important and original conclusions about the best practices when using energized fluids in tight gas sands. The models and tools presented here may be used in the future to predict behavior of any multi-phase or multi-component fracturing fluid system.

SDSS-IV MaNGA-resolved Star Formation and Molecular Gas Properties of Green Valley Galaxies: A First Look with ALMA and MaNGA

Science.gov (United States)

Lin, Lihwai; Belfiore, Francesco; Pan, Hsi-An; Bothwell, M. S.; Hsieh, Pei-Ying; Huang, Shan; Xiao, Ting; Sánchez, Sebastián F.; Hsieh, Bau-Ching; Masters, Karen; Ramya, S.; Lin, Jing-Hua; Hsu, Chin-Hao; Li, Cheng; Maiolino, Roberto; Bundy, Kevin; Bizyaev, Dmitry; Drory, Niv; Ibarra-Medel, Héctor; Lacerna, Ivan; Haines, Tim; Smethurst, Rebecca; Stark, David V.; Thomas, Daniel

2017-12-01

We study the role of cold gas in quenching star formation in the green valley by analyzing ALMA 12CO (1-0) observations of three galaxies with resolved optical spectroscopy from the MaNGA survey. We present resolution-matched maps of the star formation rate and molecular gas mass. These data are used to calculate the star formation efficiency (SFE) and gas fraction ({f}{gas}) for these galaxies separately in the central “bulge” regions and outer disks. We find that, for the two galaxies whose global specific star formation rate (sSFR) deviates most from the star formation main sequence, the gas fraction in the bulges is significantly lower than that in their disks, supporting an “inside-out” model of galaxy quenching. For the two galaxies where SFE can be reliably determined in the central regions, the bulges and disks share similar SFEs. This suggests that a decline in {f}{gas} is the main driver of lowered sSFR in bulges compared to disks in green valley galaxies. Within the disks, there exist common correlations between the sSFR and SFE and between sSFR and {f}{gas} on kiloparsec scales—the local SFE or {f}{gas} in the disks declines with local sSFR. Our results support a picture in which the sSFR in bulges is primarily controlled by {f}{gas}, whereas both SFE and {f}{gas} play a role in lowering the sSFR in disks. A larger sample is required to confirm if the trend established in this work is representative of the green valley as a whole.

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.

Less-tight versus tight control of hypertension in pregnancy.

Science.gov (United States)

Magee, Laura A; von Dadelszen, Peter; Rey, Evelyne; Ross, Susan; Asztalos, Elizabeth; Murphy, Kellie E; Menzies, Jennifer; Sanchez, Johanna; Singer, Joel; Gafni, Amiram; Gruslin, Andrée; Helewa, Michael; Hutton, Eileen; Lee, Shoo K; Lee, Terry; Logan, Alexander G; Ganzevoort, Wessel; Welch, Ross; Thornton, Jim G; Moutquin, Jean-Marie

2015-01-29

The effects of less-tight versus tight control of hypertension on pregnancy complications are unclear. We performed an open, international, multicenter trial involving women at 14 weeks 0 days to 33 weeks 6 days of gestation who had nonproteinuric preexisting or gestational hypertension, office diastolic blood pressure of 90 to 105 mm Hg (or 85 to 105 mm Hg if the woman was taking antihypertensive medications), and a live fetus. Women were randomly assigned to less-tight control (target diastolic blood pressure, 100 mm Hg) or tight control (target diastolic blood pressure, 85 mm Hg). The composite primary outcome was pregnancy loss or high-level neonatal care for more than 48 hours during the first 28 postnatal days. The secondary outcome was serious maternal complications occurring up to 6 weeks post partum or until hospital discharge, whichever was later. Included in the analysis were 987 women; 74.6% had preexisting hypertension. The primary-outcome rates were similar among 493 women assigned to less-tight control and 488 women assigned to tight control (31.4% and 30.7%, respectively; adjusted odds ratio, 1.02; 95% confidence interval [CI], 0.77 to 1.35), as were the rates of serious maternal complications (3.7% and 2.0%, respectively; adjusted odds ratio, 1.74; 95% CI, 0.79 to 3.84), despite a mean diastolic blood pressure that was higher in the less-tight-control group by 4.6 mm Hg (95% CI, 3.7 to 5.4). Severe hypertension (≥160/110 mm Hg) developed in 40.6% of the women in the less-tight-control group and 27.5% of the women in the tight-control group (Phypertension. (Funded by the Canadian Institutes of Health Research; CHIPS Current Controlled Trials number, ISRCTN71416914; ClinicalTrials.gov number, NCT01192412.).

Prime tight frames

DEFF Research Database (Denmark)

Lemvig, Jakob; Miller, Christopher; Okoudjou, Kasso A.

2014-01-01

to suggest effective analysis and synthesis computation strategies for such frames. Finally, we describe all prime frames constructed from the spectral tetris method, and, as a byproduct, we obtain a characterization of when the spectral tetris construction works for redundancies below two.......We introduce a class of finite tight frames called prime tight frames and prove some of their elementary properties. In particular, we show that any finite tight frame can be written as a union of prime tight frames. We then characterize all prime harmonic tight frames and use thischaracterization...

Sustainability and energy security : the squeeze on natural gas

International Nuclear Information System (INIS)

Hoover, G.; Howatson, A.; Parmenter, R.

2004-01-01

This paper outlines the impact of environmental policy on natural gas demand and describes alternative energy sources such as wind, solar, biomass and clean coal that can increase energy supplies. This briefing also establishes the short-, medium-, and long-term consequences of current natural gas realities. It also outlines the driving forces in Canada and the United States behind the demand for natural gas. The impact of policy formation and the phase-out of coal in Ontario are addressed along with natural gas supply prospects and the prospects and obstacles for riskier incremental supplies such as liquefied natural gas, natural gas from coal, and frontier natural gas. It was concluded that strong demand and tight supply are the factors that have driven up natural gas prices. Continued high natural gas prices in the short term will likely motivate conservation strategies at the personal household level as well as in the business and industrial sectors. Although wind power is seen as a clean, competitively prices alternative to natural gas-fired electricity generation, its contribution is not expected to change the supply and demand equilibrium. Initiatives such as the Mackenzie Valley Pipeline, the Alaskan Pipeline and drilling in the Atlantic may help balance natural gas supply and demand in the mid-term. 44 refs., 2 tabs., 7 figs

Analysis of Critical Permeabilty, Capillary Pressure and Electrical Properties for Mesaverde Tight Gas Sandstones from Western U.S. Basins

Energy Technology Data Exchange (ETDEWEB)

Alan Byrnes; Robert Cluff; John Webb; John Victorine; Ken Stalder; Daniel Osburn; Andrew Knoderer; Owen Metheny; Troy Hommertzheim; Joshua Byrnes; Daniel Krygowski; Stefani Whittaker

2008-06-30

Although prediction of future natural gas supply is complicated by uncertainty in such variables as demand, liquefied natural gas supply price and availability, coalbed methane and gas shale development rate, and pipeline availability, all U.S. Energy Information Administration gas supply estimates to date have predicted that Unconventional gas sources will be the dominant source of U.S. natural gas supply for at least the next two decades (Fig. 1.1; the period of estimation). Among the Unconventional gas supply sources, Tight Gas Sandstones (TGS) will represent 50-70% of the Unconventional gas supply in this time period (Fig. 1.2). Rocky Mountain TGS are estimated to be approximately 70% of the total TGS resource base (USEIA, 2005) and the Mesaverde Group (Mesaverde) sandstones represent the principal gas productive sandstone unit in the largest Western U.S. TGS basins including the basins that are the focus of this study (Washakie, Uinta, Piceance, northern Greater Green River, Wind River, Powder River). Industry assessment of the regional gas resource, projection of future gas supply, and exploration programs require an understanding of reservoir properties and accurate tools for formation evaluation. The goal of this study is to provide petrophysical formation evaluation tools related to relative permeability, capillary pressure, electrical properties and algorithms for wireline log analysis. Detailed and accurate moveable gas-in-place resource assessment is most critical in marginal gas plays and there is need for quantitative tools for definition of limits on gas producibility due to technology and rock physics and for defining water saturation. The results of this study address fundamental questions concerning: (1) gas storage; (2) gas flow; (3) capillary pressure; (4) electrical properties; (5) facies and upscaling issues; (6) wireline log interpretation algorithms; and (7) providing a web-accessible database of advanced rock properties. The following text

Structural diagenesis in Upper Carboniferous tight gas sandstones. Lessons learned from the Piesberg analog study

Energy Technology Data Exchange (ETDEWEB)

Steindorf, P.; Hoehne, M.; Becker, S.; Hilgers, C. [RWTH Aachen Univ. (Germany). Energy and Mineral Resources Group (EMR); Koehrer, B. [Wintershall Holding GmbH, Barnstorf (Germany)

2013-08-01

Upper Carboniferous tight gas sandstone reservoirs in NW-Germany consist of thick successions of cyclothems. Our focus is the Westphalian D of the Piesberg quarry near Osnabrueck, which exposes cemented, faulted and jointed third-order coarse- to fine-grained sandstone cycles separated by anthracite coal seams. We characterize the rocks and the lateral variation of rock properties such as porosity to better constrain input data for reservoir modelling. Three cycles are exposed, each approximately 50 m thick. Rock types can be clearly distinguished by spectral gamma ray in the quarry. Sandstones are intensely compacted and cemented with quartz and generally characterized by low porosities < 8 % (Hepycnometry on plugs and cuttings). Porosities are secondary and mainly related to detrital carbonate dissolution. Around faults dissolution is higher and the porosities can increase to up to 25%. The normal faults show different throws in the quarry and bands of shale and coal have smeared into the fault at juxtaposed beds, which may result in compartments. They dominantly strike W-E and NNW-SSE, but subordinate NE-SW striking fault patterns are also present. Joints were analyzed in a 50 x 50 m section of the quarry wall using Lidar (Light detection and ranging) laser scanning, which allows the characterization of the lithology and quantitative measurement of bedding and fracture orientation data in inaccessible areas. NNE-SSW and W-E joint sets are accompanied by northeasterly and northwesterly striking sets. Around faults, fault planes and fractures are cemented with quartz veins, showing localized mass transport. Due to the intense cementation, the sandstones can reach uniaxial strengths of more than 100 MPa normal to bedding, and approximately 50 MPa parallel to bedding. Sandstone beds within and close to faults are leached by fluids, and their uniaxial strength is reduced by a factor of more than two. Our high resolution field data enables a better understanding of

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.

For the North, from the North : Enbridge perspectives on a Mackenzie Valley gas pipeline

International Nuclear Information System (INIS)

Porter, E.

2000-01-01

The increase in natural gas demand and strong gas prices are the main driving forces behind northern pipeline development. While Western Canada can supply much of the demand growth to key markets in the Pacific Northwest, California, Eastern Canada, as well as the Eastern and Midwestern U.S. it is not expected to supply all the growth. Producers are acquiring land in the Northwest Territories (NWT) and planning to increase drilling activity. In February 2000, Imperial, Gulf, Shell and Mobil entered into an agreement to study the feasibility of developing Mackenzie Delta gas, a study in which Enbridge Inc. participated. Enbridge is the major transporter of Canadian crude oil and liquids and they have a growing involvement in natural gas transmission. They also own and operate the largest gas distribution company in Canada. They have extensive Northern experience and already operate two pipelines in the NWT. The proposed 2,100 km, 36 inch pipeline will transport 1.2 bcf/d of natural gas increasing to 1.7 bcf/d with more compression. Its estimated cost is $4.2 billion. Some of the economic risks of such a project include the need for large amounts of equity, timing of market development, competing sources of gas, and stability of gas prices. The multitude of regulatory processes are also complex. Clarity is needed in many jurisdictional processes. Support of indigenous people is also crucial. A historic January 25, 2000 meeting of Aboriginal leaders of the Northwest Territories resulted in a declaration of support for a Mackenzie Valley pipeline. Protecting the permafrost is also a priority when constructing and operating a pipeline in the North. It is unlikely that Mackenzie Delta gas will flow before 7 years .13 figs

Cost-Benefit Analysis applied to the natural gas program for vehicles in the Metropolitan Area of the Aburra Valley

International Nuclear Information System (INIS)

Saldarriaga Isaza, Carlos Adrian; Vasquez Sanchez, Edison; Chavarria Munera, Sergio

2011-01-01

This article presents the evaluation of the natural gas program for vehicles applied in Metropolitan Area of the Aburra Valley. By using the Cost- Benefit Analysis method, four cost variables were identified: private, fiscal, gas tax, and conversion tax; and three types of benefits: private, fiscal and social. For the environmental social benefit estimation the benefit transfer technique was employed, carrying out meta-analysis function estimation. The cost-benefit net outcome is positive and favors the program application in the study site; in real terms the total profits are about COP$ 803265 million for the complete eight year period it took place (2001- 2008).

Many-body effects in valleytronics: direct measurement of valley lifetimes in single-layer MoS2.

Science.gov (United States)

Mai, Cong; Barrette, Andrew; Yu, Yifei; Semenov, Yuriy G; Kim, Ki Wook; Cao, Linyou; Gundogdu, Kenan

2014-01-08

Single layer MoS2 is an ideal material for the emerging field of "valleytronics" in which charge carrier momentum can be finely controlled by optical excitation. This system is also known to exhibit strong many-body interactions as observed by tightly bound excitons and trions. Here we report direct measurements of valley relaxation dynamics in single layer MoS2, by using ultrafast transient absorption spectroscopy. Our results show that strong Coulomb interactions significantly impact valley population dynamics. Initial excitation by circularly polarized light creates electron-hole pairs within the K-valley. These excitons coherently couple to dark intervalley excitonic states, which facilitate fast electron valley depolarization. Hole valley relaxation is delayed up to about 10 ps due to nondegeneracy of the valence band spin states. Intervalley biexciton formation reveals the hole valley relaxation dynamics. We observe that biexcitons form with more than an order of magnitude larger binding energy compared to conventional semiconductors. These measurements provide significant insight into valley specific processes in 2D semiconductors. Hence they could be used to suggest routes to design semiconducting materials that enable control of valley polarization.

Less-Tight versus Tight Control of Hypertension in Pregnancy

NARCIS (Netherlands)

Magee, Laura A.; von Dadelszen, Peter; Rey, Evelyne; Ross, Susan; Asztalos, Elizabeth; Murphy, Kellie E.; Menzies, Jennifer; Sanchez, Johanna; Singer, Joel; Gafni, Amiram; Gruslin, Andrée; Helewa, Michael; Hutton, Eileen; Lee, Shoo K.; Lee, Terry; Logan, Alexander G.; Ganzevoort, Wessel; Welch, Ross; Thornton, Jim G.; Moutquin, Jean-Marie

2015-01-01

BACKGROUND The effects of less-tight versus tight control of hypertension on pregnancy complications are unclear. METHODS We performed an open, international, multicenter trial involving women at 14 weeks 0 days to 33 weeks 6 days of gestation who had nonproteinuric preexisting or gestational

Development of a new quantitative gas permeability method for dental implant-abutment connection tightness assessment

Science.gov (United States)

2011-01-01

Background Most dental implant systems are presently made of two pieces: the implant itself and the abutment. The connection tightness between those two pieces is a key point to prevent bacterial proliferation, tissue inflammation and bone loss. The leak has been previously estimated by microbial, color tracer and endotoxin percolation. Methods A new nitrogen flow technique was developed for implant-abutment connection leakage measurement, adapted from a recent, sensitive, reproducible and quantitative method used to assess endodontic sealing. Results The results show very significant differences between various sealing and screwing conditions. The remaining flow was lower after key screwing compared to hand screwing (p = 0.03) and remained different from the negative test (p = 0.0004). The method reproducibility was very good, with a coefficient of variation of 1.29%. Conclusions Therefore, the presented new gas flow method appears to be a simple and robust method to compare different implant systems. It allows successive measures without disconnecting the abutment from the implant and should in particular be used to assess the behavior of the connection before and after mechanical stress. PMID:21492459

Predicting the valley physics of silicon quantum dots directly from a device layout

Science.gov (United States)

Gamble, John King; Harvey-Collard, Patrick; Jacobson, N. Tobias; Bacewski, Andrew D.; Nielsen, Erik; Montaño, Inès; Rudolph, Martin; Carroll, Malcolm S.; Muller, Richard P.

Qubits made from electrostatically-defined quantum dots in Si-based systems are excellent candidates for quantum information processing applications. However, the multi-valley structure of silicon's band structure provides additional challenges for the few-electron physics critical to qubit manipulation. Here, we present a theory for valley physics that is predictive, in that we take as input the real physical device geometry and experimental voltage operation schedule, and with minimal approximation compute the resulting valley physics. We present both effective mass theory and atomistic tight-binding calculations for two distinct metal-oxide-semiconductor (MOS) quantum dot systems, directly comparing them to experimental measurements of the valley splitting. We conclude by assessing these detailed simulations' utility for engineering desired valley physics in future devices. Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. The authors gratefully acknowledge support from the Sandia National Laboratories Truman Fellowship Program, which is funded by the Laboratory Directed Research and Development (LDRD) Program.

Improving horizontal completions on heterogeneous tight shales

Energy Technology Data Exchange (ETDEWEB)

Suarez-Rivera, Roberto; Deenadayalu, Chaitanya; Chertov, Maxim; Novalo Hartanto, Ricardo; Gathogo, Patrick [Schlumberger (United States); Kunjir, Rahul [University of Utah (United States)

2011-07-01

Evaluation of the two formation characteristics conducive to economic well production is important when tight shale formation characterization and completion design are being considered. This paper presents the basic understanding required to improve the efficiency of horizontal completions in oil and gas producing shales. Guidelines are defined for effective perforation and fracturing to improve the efficiency and sustainability of horizontal completions using extensive laboratory characterization of mechanical properties on core, core/log integration and continuous mapping of these properties by logging-while-drilling (LWD) methods. The objective is to improve completion design efficiency. This is accomplished by suitable selection of perforation intervals based on an understanding of the relevant physical processes and rock characterization. Conditions at two reservoir regions, the near-wellbore and the far-wellbore, are outlined and are essential to completion design. From the study, it can be concluded that tight shales are strongly anisotropic and cannot be approximated using isotropic models.

Tightness and suitability evaluation of abandoned salt caverns served as hydrocarbon energies storage under adverse geological conditions (AGC)

International Nuclear Information System (INIS)

Wei, Liu; Jie, Chen; Deyi, Jiang; Xilin, Shi; Yinping, Li; Daemen, J.J.K.; Chunhe, Yang

2016-01-01

Highlights: • Tightness conditions are set to assess use of old caverns for hydrocarbons storage. • Gas seepage and tightness around caverns are numerically simulated under AGC. • κ of interlayers act as a key factor to affect the tightness and use of salt cavern. • The threshold upper permeability of interlayers is proposed for storing oil and gas. • Three types of real application are introduced by using the tightness conditions. - Abstract: In China, the storage of hydrocarbon energies is extremely insufficient partially due to the lack of storage space, but on the other side the existence of a large number of abandoned salt caverns poses a serious threat to safety and geological environments. Some of these caverns, defined as abandoned caverns under adverse geological conditions (AGC), are expected to store hydrocarbon energies (natural gas or crude oil) to reduce the risk of potential disasters and simultaneously support the national strategic energy reserve of China. Herein, a series of investigations primarily related to the tightness and suitability of the caverns under AGC is performed. Laboratory measurements to determine the physical and mechanical properties as well as porosity and permeability of bedded salt cores from a near target cavern are implemented to determine the petro-mechanical properties and basic parameters for further study. The results show that the mechanical properties of the bedded rock salts are satisfactory for the stability of caverns. The interface between the salt and interlayers exhibits mechanical properties that are between those of rock salt and interlayers and in particular is not a weak zone. The silty mudstone interlayers have relatively high porosity and permeability, likely due to their low content of clay minerals and the presence of halite-filled cracks. The conditions for evaluating the tightness and suitability of a cavern for storing hydrocarbons are proposed, including “No tensile stress,” �

Tight closure and vanishing theorems

International Nuclear Information System (INIS)

Smith, K.E.

2001-01-01

Tight closure has become a thriving branch of commutative algebra since it was first introduced by Mel Hochster and Craig Huneke in 1986. Over the past few years, it has become increasingly clear that tight closure has deep connections with complex algebraic geometry as well, especially with those areas of algebraic geometry where vanishing theorems play a starring role. The purpose of these lectures is to introduce tight closure and to explain some of these connections with algebraic geometry. Tight closure is basically a technique for harnessing the power of the Frobenius map. The use of the Frobenius map to prove theorems about complex algebraic varieties is a familiar technique in algebraic geometry, so it should perhaps come as no surprise that tight closure is applicable to algebraic geometry. On the other hand, it seems that so far we are only seeing the tip of a large and very beautiful iceberg in terms of tight closure's interpretation and applications to algebraic geometry. Interestingly, although tight closure is a 'characteristic p' tool, many of the problems where tight closure has proved useful have also yielded to analytic (L2) techniques. Despite some striking parallels, there had been no specific result directly linking tight closure and L∼ techniques. Recently, however, the equivalence of an ideal central to the theory of tight closure was shown to be equivalent to a certain 'multiplier ideal' first defined using L2 methods. Presumably, deeper connections will continue to emerge. There are two main types of problems for which tight closure has been helpful: in identifying nice structure and in establishing uniform behavior. The original algebraic applications of tight closure include, for example, a quick proof of the Hochster-Roberts theorem on the Cohen-Macaulayness of rings of invariants, and also a refined version of the Brianqon-Skoda theorem on the uniform behaviour of integral closures of powers of ideals. More recent, geometric

unconventional natural gas reservoirs

International Nuclear Information System (INIS)

Correa G, Tomas F; Osorio, Nelson; Restrepo R, Dora P

2009-01-01

This work is an exploration about different unconventional gas reservoirs worldwide: coal bed methane, tight gas, shale gas and gas hydrate? describing aspects such as definition, reserves, production methods, environmental issues and economics. The overview also mentioned preliminary studies about these sources in Colombia.

How unconventional gas prospers without tax incentives

International Nuclear Information System (INIS)

Kuuskraa, V.A.; Stevens, S.H.

1995-01-01

It was widely believed that the development of unconventional natural gas (coalbed methane, gas shales, and tight gas) would die once US Sec. 29 credits stopped. Quieter voices countered, and hoped, that technology advances would keep these large but difficult to produce gas resources alive and maybe even healthy. Sec. 29 tax credits for new unconventional gas development stopped at the end of 1992. Now, nearly three years later, who was right and what has happened? There is no doubt that Sec. 29 tax credits stimulated the development of coalbed methane, gas shales, and tight gas. What is less known is that the tax credits helped spawn and push into use an entire new set of exploration, completion, and production technologies founded on improved understanding of unconventional gas reservoirs. As set forth below, while the incentives inherent in Sec. 29 provided the spark, it has been the base of science and technology that has maintained the vitality of these gas sources. The paper discusses the current status; resource development; technology; unusual production, proven reserves, and well completions if coalbed methane, gas shales, and tight gas; and international aspects

Flow and Transport in Tight and Shale Formations: A Review

KAUST Repository

Salama, Amgad

2017-09-18

A review on the recent advances of the flow and transport phenomena in tight and shale formations is presented in this work. Exploration of oil and gas in resources that were once considered inaccessible opened the door to highlight interesting phenomena that require attention and understanding. The length scales associated with transport phenomena in tight and shale formations are rich. From nanoscale phenomena to field-scale applications, a unified frame that is able to encounter the varieties of phenomena associated with each scale may not be possible. Each scale has its own tools and limitations that may not, probably, be suitable at other scales. Multiscale algorithms that effectively couple simulations among various scales of porous media are therefore important. In this article, a review of the different length scales and the tools associated with each scale is introduced. Highlights on the different phenomena pertinent to each scale are summarized. Furthermore, the governing equations describing flow and transport phenomena at different scales are investigated. In addition, methods to solve these equations using numerical techniques are introduced. Cross-scale analysis and derivation of linear and nonlinear Darcy\\'s scale laws from pore-scale governing equations are described. Phenomena occurring at molecular scales and their thermodynamics are discussed. Flow slippage at the nanosize pores and its upscaling to Darcy\\'s scale are highlighted. Pore network models are discussed as a viable tool to estimate macroscopic parameters that are otherwise difficult to measure. Then, the environmental aspects associated with the different technologies used in stimulating the gas stored in tight and shale formations are briefly discussed.

Flow and Transport in Tight and Shale Formations: A Review

KAUST Repository

Salama, Amgad; El-Amin, Mohamed; Kumar, Kundan; Sun, Shuyu

2017-01-01

A review on the recent advances of the flow and transport phenomena in tight and shale formations is presented in this work. Exploration of oil and gas in resources that were once considered inaccessible opened the door to highlight interesting phenomena that require attention and understanding. The length scales associated with transport phenomena in tight and shale formations are rich. From nanoscale phenomena to field-scale applications, a unified frame that is able to encounter the varieties of phenomena associated with each scale may not be possible. Each scale has its own tools and limitations that may not, probably, be suitable at other scales. Multiscale algorithms that effectively couple simulations among various scales of porous media are therefore important. In this article, a review of the different length scales and the tools associated with each scale is introduced. Highlights on the different phenomena pertinent to each scale are summarized. Furthermore, the governing equations describing flow and transport phenomena at different scales are investigated. In addition, methods to solve these equations using numerical techniques are introduced. Cross-scale analysis and derivation of linear and nonlinear Darcy's scale laws from pore-scale governing equations are described. Phenomena occurring at molecular scales and their thermodynamics are discussed. Flow slippage at the nanosize pores and its upscaling to Darcy's scale are highlighted. Pore network models are discussed as a viable tool to estimate macroscopic parameters that are otherwise difficult to measure. Then, the environmental aspects associated with the different technologies used in stimulating the gas stored in tight and shale formations are briefly discussed.

Proceedings of the natural gas research and development contractors review meeting

Energy Technology Data Exchange (ETDEWEB)

Malone, R.D.; Shoemaker, H.D.; Byrer, C.W. (eds.)

1990-11-01

The purpose of this meeting was to present results of the research in the DOE-sponsored Natural Gas Program, and simultaneously to provide a forum for real-time technology transfer, to the active research community, to the interested public, and to the natural gas industry, who are the primary users of this technology. The current research focus is to expand the base of near-term and mid-term economic gas resources through research activities in Eastern Tight Gas, Western Tight Gas, Secondary Gas Recovery (increased recovery of gas from mature fields); to enhance utilization, particularly of remote gas resources through research in Natural Gas to Liquids Conversion; and to develop additional, long term, potential gas resources through research in Gas Hydrates and Deep Gas. With the increased national emphasis on the use of natural gas, this forum has been expanded to include summaries of DOE-sponsored research in energy-related programs and perspectives on the importance of gas to future world energy. Thirty-two papers and fourteen poster presentations were given in seven formal, and one informal, sessions: Three general sessions (4 papers); Western Tight Gas (6 papers); Eastern Tight Gas (8 papers); Conventional/Speculative Resources (8 papers); and Gas to Liquids (6 papers). Individual reports are processed separately on the data bases.

North American natural gas supply and demand

International Nuclear Information System (INIS)

Goobie, G.

2006-01-01

This presentation was given by leading energy analysts Pervin and Gertz, and provided their outlook on the North American natural gas supply and demand as well as transportation and processing options for the Mackenzie Valley project and the Alaska natural gas project. Arctic gas development was discussed in relation to larger North American and world energy markets. The impacts of liquefied natural gas (LNG) infrastructure development were compared with the potential impacts of the Alaska and Mackenzie Valley pipelines. A review of North American gas supplies was presented. LNG imports to the United States are expected to exceed 8 BCF/D by 2010. In addition, huge growth in the LNG markets is expected in middle eastern countries as well as in Africa. There is currently strong growth in liquefaction capacity in most regions. However, many proposed LNG terminals will not proceed due to opposition on the west coast of North America. It is also expected that natural gas liquids (NGL) delivered to Alberta from the Mackenzie Valley Gas project are expected to be used by the heavy oil industry. Canadian crude supplies are expected to grow to nearly 4 million barrels per day by 2015. The impacts of Alaska and Mackenzie Valley gas projects on western NGL markets and the petrochemicals industry were reviewed. It was concluded that major investments in supply and infrastructure are need in order to develop Arctic gas, as LNG is likely to be the largest source of incremental supply. tabs., figs

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

Recovery Act. Sub-Soil Gas and Fluid Inclusion Exploration and Slim Well Drilling, Pumpernickel Valley, Nevada

Energy Technology Data Exchange (ETDEWEB)

Fairbank, Brian D. [Nevada Geothermal Power Company, Las Vegas, NV (United States)

2015-03-27

Nevada Geothermal Power Company (NGP) was awarded DOE Award DE-EE0002834 in January 2010 to conduct sub-soil gas and fluid inclusion studies and slim well drilling at its Black Warrior Project (now known as North Valley) in Washoe and Churchill Counties, Nevada. The project was designed to apply highly detailed, precise, low-cost subsoil and down-hole gas geochemistry methods from the oil and gas industry to identify upflow zone drilling targets in an undeveloped geothermal prospect. NGP ran into multiple institutional barriers with the Black Warrior project relating to property access and extensive cultural survey requirement. NGP requested that the award be transferred to NGP’s Pumpernickel Valley project, due to the timing delay in obtaining permits, along with additional over-budget costs required. Project planning and permit applications were developed for both the original Black Warrior location and at Pumpernickel. This included obtaining proposals from contractors able to conduct required environmental and cultural surveying, designing the two-meter probe survey methodology and locations, and submitting Notices of Intent and liaising with the Bureau of Land Management to have the two-meter probe work approved. The award had an expiry date of April 30, 2013; however, due to the initial project delays at Black Warrior, and the move of the project from Black Warrior to Pumpernickel, NGP requested that the award deadline be extended. DOE was amenable to this, and worked with NGP to extend the deadline. However, following the loss of the Blue Mountain geothermal power plant in Nevada, NGP’s board of directors changed the company’s mandate to one of cash preservation. NGP was unable to move forward with field work on the Pumpernickel property, or any of its other properties, until additional funding was secured. NGP worked to bring in a project partner to form a joint venture on the property, or to buy the property. This was unsuccessful, and NGP notified

Potential evaluation of CO2 storage and enhanced oil recovery of tight oil reservoir in the Ordos Basin, China.

Science.gov (United States)

Tian, Xiaofeng; Cheng, Linsong; Cao, Renyi; Zhang, Miaoyi; Guo, Qiang; Wang, Yimin; Zhang, Jian; Cui, Yu

2015-07-01

Carbon -di-oxide (CO2) is regarded as the most important greenhouse gas to accelerate climate change and ocean acidification. The Chinese government is seeking methods to reduce anthropogenic CO2 gas emission. CO2 capture and geological storage is one of the main methods. In addition, injecting CO2 is also an effective method to replenish formation energy in developing tight oil reservoirs. However, exiting methods to estimate CO2 storage capacity are all based on the material balance theory. This was absolutely correct for normal reservoirs. However, as natural fractures widely exist in tight oil reservoirs and majority of them are vertical ones, tight oil reservoirs are not close. Therefore, material balance theory is not adaptive. In the present study, a new method to calculate CO2 storage capacity is presented. The CO2 effective storage capacity, in this new method, consisted of free CO2, CO2 dissolved in oil and CO2 dissolved in water. Case studies of tight oil reservoir from Ordos Basin was conducted and it was found that due to far lower viscosity of CO2 and larger solubility in oil, CO2 could flow in tight oil reservoirs more easily. As a result, injecting CO2 in tight oil reservoirs could obviously enhance sweep efficiency by 24.5% and oil recovery efficiency by 7.5%. CO2 effective storage capacity of Chang 7 tight oil reservoir in Longdong area was 1.88 x 10(7) t. The Chang 7 tight oil reservoir in Ordos Basin was estimated to be 6.38 x 10(11) t. As tight oil reservoirs were widely distributed in Songliao Basin, Sichuan Basin and so on, geological storage capacity of CO2 in China is potential.

Tight junctions and human diseases.

Science.gov (United States)

Sawada, Norimasa; Murata, Masaki; Kikuchi, Keisuke; Osanai, Makoto; Tobioka, Hirotoshi; Kojima, Takashi; Chiba, Hideki

2003-09-01

Tight junctions are intercellular junctions adjacent to the apical end of the lateral membrane surface. They have two functions, the barrier (or gate) function and the fence function. The barrier function of tight junctions regulates the passage of ions, water, and various macromolecules, even of cancer cells, through paracellular spaces. The barrier function is thus relevant to edema, jaundice, diarrhea, and blood-borne metastasis. On the other hand, the fence function maintains cell polarity. In other words, tight junctions work as a fence to prevent intermixing of molecules in the apical membrane with those in the lateral membrane. This function is deeply involved in cancer cell biology, in terms of loss of cell polarity. Of the proteins comprising tight junctions, integral membrane proteins occludin, claudins, and JAMs have been recently discovered. Of these molecules, claudins are exclusively responsible for the formation of tight-junction strands and are connected with the actin cytoskeleton mediated by ZO-1. Thus, both functions of tight junctions are dependent on the integrity of the actin cytoskeleton as well as ATP. Mutations in the claudin14 and the claudin16 genes result in hereditary deafness and hereditary hypomagnesemia, respectively. Some pathogenic bacteria and viruses target and affect the tight-junction function, leading to diseases. In this review, the relationship between tight junctions and human diseases is summarized.

Upper Paleozoic coal measures and unconventional natural gas systems of the Ordos Basin, China

Directory of Open Access Journals (Sweden)

Xuan Tang

2012-11-01

Full Text Available Upper Paleozoic coal measures in the Ordos Basin consist of dark mudstone and coal beds and are important source rocks for gas generation. Gas accumulations include coal-bed methane (CBM, tight gas and conventional gas in different structural areas. CBM accumulations are mainly distributed in the marginal area of the Ordos Basin, and are estimated at 3.5 × 1012 m3. Tight gas accumulations exist in the middle part of the Yishan Slope area, previously regarded as the basin-centered gas system and now considered as stratigraphic lithologic gas reservoirs. This paper reviews the characteristics of tight gas accumulations: poor physical properties (porosity < 8%, permeability < 0.85 × 10−3 μm2, abnormal pressure and the absence of well-defined gas water contacts. CBM is a self-generation and self-reservoir, while gas derived from coal measures migrates only for a short distance to accumulate in a tight reservoir and is termed near-generation and near-reservoir. Both CBM and tight gas systems require source rocks with a strong gas generation ability that extends together over wide area. However, the producing area of the two systems may be significantly different.

Effect of pore structure on the seepage characteristics of tight sandstone reservoirs: A case study of Upper Jurassic Penglaizhen Fm reservoirs in the western Sichuan Basin

Directory of Open Access Journals (Sweden)

Liqiang Sima

2017-01-01

Full Text Available Tight sandstone reservoirs are characterized by complex pore structures and strong heterogeneity, and their seepage characteristics are much different from those of conventional sandstone reservoirs. In this paper, the tight sandstone reservoirs of Upper Jurassic Penglaizhen Fm in western Sichuan Basin were analyzed in terms of their pore structures by using the data about physical property, mercury injection and nuclear magnetic resonance (NMR tests. Then, the seepage characteristics and the gas–water two-phase migration mechanisms and distribution of tight sandstone reservoirs with different types of pore structures in the process of hydrocarbon accumulation and development were simulated by combining the relative permeability experiment with the visual microscopic displacement model. It is shown that crotch-like viscous fingering occurs in the process of gas front advancing in reservoirs with different pore structures. The better the pore structure is, the lower the irreducible water saturation is; the higher the gas-phase relative permeability of irreducible water is, the more easily the gas reservoir can be developed. At the late stage of development, the residual gas is sealed in reservoirs in the forms of bypass, cutoff and dead end. In various reservoirs, the interference between gas and water is stronger, so gas and water tends to be produced simultaneously. The sealed gas may reduce the production rate of gas wells significantly, and the existence of water phase may reduce the gas permeability greatly; consequently, the water-bearing low-permeability tight sandstone gas reservoirs reveal serious water production, highly-difficult development and low-recovery percentage at the late stage, which have adverse impacts on the effective production and development of gas wells.

Device-Level Models Using Multi-Valley Effective Mass

Science.gov (United States)

Baczewski, Andrew D.; Frees, Adam; Gamble, John King; Gao, Xujiao; Jacobson, N. Tobias; Mitchell, John A.; Montaño, Inès; Muller, Richard P.; Nielsen, Erik

2015-03-01

Continued progress in quantum electronics depends critically on the availability of robust device-level modeling tools that capture a wide range of physics and effective mass theory (EMT) is one means of building such models. Recent developments in multi-valley EMT show quantitative agreement with more detailed atomistic tight-binding calculations of phosphorus donors in silicon (Gamble, et. al., arXiv:1408.3159). Leveraging existing PDE solvers, we are developing a framework in which this multi-valley EMT is coupled to an integrated device-level description of several experimentally active qubit technologies. Device-level simulations of quantum operations will be discussed, as well as the extraction of process matrices at this level of theory. The authors gratefully acknowledge support from the Sandia National Laboratories Truman Fellowship Program, which is funded by the Laboratory Directed Research and Development (LDRD) Program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Security Administration under contract DE-AC04-94AL85000.

3D Retro-Deformation of the Rotliegend of the `Tight Gas' Area, NGB

Science.gov (United States)

Tanner, D. C.; Krawczyk, C.; Oncken, O.; Baunack, C.; Gaupp, R.; Littke, R.; Schubarth-Engelschall, J.; Schwarzer, D.; Solms, M.; Trappe, H.

2003-04-01

We have constructed a detailed three-dimensional, geometrical model of the Rotliegend `Tight-Gas' reservoir (10 × 20 km^2) of the North German Basin (NGB) from 3D seismic and borehole data. From this data we have compiled an incremental tectonic history of the area, and retro-deformed faults within the model in time and 3D space. The Top Rotliegend surface lies at depths between 4490 m and 4910 m. We recognise three fault generations in the Rotliegend strata: 1) A NW--SE striking strike-slip fault. 2) N--S striking, dip-slip faults. 3) NE--SW striking faults with late and minor displacements. Vertical throw on all the faults is less than 150 m, but the strike-slip fault is characterized by rapid changes in fault throw along strike, whereas the dip-slip faults are composed of one or more segments which have coalesced over time. We envisage that 1) and 2) faults developed coevally in a transtensive setting. We perform 3D geometrical retro-deformation (i.e. reconstruction of the faulted blocks to the undeformed state) using the inclined-shear method. In this method, the hanging-wall is displaced upon the fault surface along a distinct movement vector, which is determined by the previous tectonic model. Morphology (i.e. curvature) of the fault causes passive deformation of the hanging-wall, which is accommodated by shear along a 3D vector. We present detailed fault analysis, and maps of the quantities and directions of the strain within the Rotliegend strata due to fault movement.

Water into gas

International Nuclear Information System (INIS)

Woodord, Julian.

1997-01-01

This article examines the move by water utilities into the gas market and potentially into the electricity supply market. Operation by Dee Valley Holdings, York Waterworks, York Gas, and North Wales Gas are reported, and investment, use of mail campaigns and telemarketing to secure customers, and the opportunities offered by diversification are considered. (UK)

Experience in North America Tight Oil Reserves Development. Horizontal Wells and Multistage Hydraulic Fracturing

Directory of Open Access Journals (Sweden)

R.R. Ibatullin

2017-09-01

Full Text Available The accelerated development of horizontal drilling technology in combination with the multistage hydraulic fracturing of the reservoir has expanded the geological conditions for commercial oil production from tight reservoirs in North America. Geological and physical characteristics of tight reservoirs in North America are presented, as well as a comparison of the geological and physical properties of the reservoirs of the Western Canadian Sedimentary Basin and the Volga-Ural oil and gas province, in particular, in the territory of Tatarstan. The similarity of these basins is shown in terms of formation and deposition. New drilling technologies for horizontal wells (HW and multistage hydraulic fracturing are considered. The drilling in tight reservoirs is carried out exclusively on hydrocarbon-based muds The multi-stage fracturing technology with the use of sliding sleeves, and also slick water – a low-viscous carrier for proppant is the most effective solution for conditions similar to tight reservoirs in the Devonian formation of Tatarstan. Tax incentives which are actively used for the development of HW and multistage fracturing technologies in Canada are described. wells, multistage fracturing

Mackenzie Valley Pipeline market demand, supply, and infrastructure analysis : final report

International Nuclear Information System (INIS)

2004-01-01

Mackenzie Valley Pipeline Co-Venturers is a consortium of petroleum companies proposing to construct a 1,400 km long, large-diameter, high-pressure natural gas transmission pipeline from the northwestern edge of the Northwest Territories to the Alberta-Northwest Territories border. The Mackenzie Valley Pipeline will bring natural gas from the Mackenzie Delta region to markets in Alberta, central and eastern Canada and the United States. Navigant Consulting Ltd. prepared this assessment of the long-term market need for natural gas produced from the Mackenzie Delta. It presents an analysis of gas demand, supply and infrastructure. Three sensitivity cases were examined, incorporating different assumptions about the initial capacity of the pipeline, potential expansion of its capacity and different levels of gas demand in Canada and the United States. The report indicates that gas markets in North America support construction of the proposed 34 million cubic metre per day pipeline in the 2009 timeframe, with possible expansion in 2015 and 2020. It also indicates that there will be enough capacity on the intra-Alberta gas transmission system to accommodate the projected deliveries of Mackenzie Delta gas. The increase in gas demand is due to an increase in residential and commercial gas consumption, electric power generation and the energy intensive bitumen extraction and processing activities in the Alberta oil sands industry. 36 tabs., 56 figs

Vitrification process equipment design for the West Valley Demonstration Project

International Nuclear Information System (INIS)

Chapman, C.C.; Drosjack, W.P.

1988-10-01

The vitrification process and equipment design is nearing completion for the West Valley Project. This report provides the basis and current status for the design of the major vessels and equipment within the West Valley Vitrification Plant. A review of the function and key design features of the equipment is also provided. The major subsystems described include the feed preparation and delivery systems, the melter, the canister handling systems, and the process off-gas system. 11 refs., 33 figs., 4 tabs

Petroleum systems and geologic assessment of undiscovered oil and gas, Cotton Valley group and Travis Peak-Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces of the northern Gulf Coast region. Chapters 1-7.

Science.gov (United States)

,

2006-01-01

The purpose of the U.S. Geological Survey's (USGS) National Oil and Gas Assessment is to develop geologically based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the United States. The USGS recently completed an assessment of undiscovered oil and gas potential of the Cotton Valley Group and Travis Peak and Hosston Formations in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces in the Gulf Coast Region (USGS Provinces 5048 and 5049). The Cotton Valley Group and Travis Peak and Hosston Formations are important because of their potential for natural gas resources. This assessment is based on geologic principles and uses the total petroleum system concept. The geologic elements of a total petroleum system include hydrocarbon source rocks (source rock maturation, hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). The USGS used this geologic framework to define one total petroleum system and eight assessment units. Seven assessment units were quantitatively assessed for undiscovered oil and gas resources.

The impact of past waste management practices on future tourist development. Turner Valley gas plant: A case study

International Nuclear Information System (INIS)

Hill, D.

1992-12-01

The reclamation of older sour gas plants in western Canada poses a number of problems as past production and waste management practices were not well documented, leading to a concern about possible soil and groundwater contamination. The Turner Valley Gas Plant, the oldest sour gas plant in Alberta, was examined as a site for an industrial museum. Production methods and waste disposal techniques were researched and documented, areas of environmental contamination were located and sampling regimes were established, and a site redevelopment concept was developed that would be sensitive to tourism needs, environmental concerns and reclamation requirements. Data were derived from government and company archives, airphotos, site visits, and interviews with former employees. A number of specific areas on the site requiring reclamation were identified, including areas where likely soil contamination with sulfur, hydrocarbons, mercury, polychlorinated biphenyls, or chromate exists. Methods that can be used to remediate soils and groundwater at the site at low cost are presented. The viability of an industrial museum is supported, with recommendations that the existing buildings be reused, the site be revegetated to reduce heat and dust, that underground hazards such as pits and tanks be buried, and visitor interest be encouraged. 49 refs., 32 figs., 2 tabs

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.

Gas separation membrane module assembly

Science.gov (United States)

Wynn, Nicholas P [Palo Alto, CA; Fulton, Donald A [Fairfield, CA

2009-03-31

A gas-separation membrane module assembly and a gas-separation process using the assembly. The assembly includes a set of tubes, each containing gas-separation membranes, arranged within a housing. The housing contains a tube sheet that divides the space within the housing into two gas-tight spaces. A permeate collection system within the housing gathers permeate gas from the tubes for discharge from the housing.

Numerical Investigation of Cross Flow Phenomena in a Tight-Lattice Rod Bundle Using Advanced Interface Tracking Method

Science.gov (United States)

Zhang, Weizhong; Yoshida, Hiroyuki; Ose, Yasuo; Ohnuki, Akira; Akimoto, Hajime; Hotta, Akitoshi; Fujimura, Ken

In relation to the design of an innovative FLexible-fuel-cycle Water Reactor (FLWR), investigation of thermal-hydraulic performance in tight-lattice rod bundles of the FLWR is being carried out at Japan Atomic Energy Agency (JAEA). The FLWR core adopts a tight triangular lattice arrangement with about 1 mm gap clearance between adjacent fuel rods. In view of importance of accurate prediction of cross flow between subchannels in the evaluation of the boiling transition (BT) in the FLWR core, this study presents a statistical evaluation of numerical simulation results obtained by a detailed two-phase flow simulation code, TPFIT, which employs an advanced interface tracking method. In order to clarify mechanisms of cross flow in such tight lattice rod bundles, the TPFIT is applied to simulate water-steam two-phase flow in two modeled subchannels. Attention is focused on instantaneous fluctuation characteristics of cross flow. With the calculation of correlation coefficients between differential pressure and gas/liquid mixing coefficients, time scales of cross flow are evaluated, and effects of mixing section length, flow pattern and gap spacing on correlation coefficients are investigated. Differences in mechanism between gas and liquid cross flows are pointed out.

Agricultural Influences on Cache Valley, Utah Air Quality During a Wintertime Inversion Episode

Science.gov (United States)

Silva, P. J.

2017-12-01

Several of northern Utah's intermountain valleys are classified as non-attainment for fine particulate matter. Past data indicate that ammonium nitrate is the major contributor to fine particles and that the gas phase ammonia concentrations are among the highest in the United States. During the 2017 Utah Winter Fine Particulate Study, USDA brought a suite of online and real-time measurement methods to sample particulate matter and potential gaseous precursors from agricultural emissions in the Cache Valley. Instruments were co-located at the State of Utah monitoring site in Smithfield, Utah from January 21st through February 12th, 2017. A Scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) acquired size distributions of particles from 10 nm - 10 μm in 5-min intervals. A URG ambient ion monitor (AIM) gave hourly concentrations for gas and particulate ions and a Chromatotec Trsmedor gas chromatograph obtained 10 minute measurements of gaseous sulfur species. High ammonia concentrations were detected at the Smithfield site with concentrations above 100 ppb at times, indicating a significant influence from agriculture at the sampling site. Ammonia is not the only agricultural emission elevated in Cache Valley during winter, as reduced sulfur gas concentrations of up to 20 ppb were also detected. Dimethylsulfide was the major sulfur-containing gaseous species. Analysis indicates that particle growth and particle nucleation events were both observed by the SMPS. Relationships between gas and particulate concentrations and correlations between the two will be discussed.

Stability of spinor Fermi gases in tight waveguides

International Nuclear Information System (INIS)

Campo, A. del; Muga, J. G.; Girardeau, M. D.

2007-01-01

The two- and three-body correlation functions of the ground state of an optically trapped ultracold spin-(1/2) Fermi gas (SFG) in a tight waveguide [one-dimensional (1D) regime] are calculated in the plane of even- and odd-wave coupling constants, assuming a 1D attractive zero-range odd-wave interaction induced by a 3D p-wave Feshbach resonance, as well as the usual repulsive zero-range even-wave interaction stemming from 3D s-wave scattering. The calculations are based on the exact mapping from the SFG to a 'Lieb-Liniger-Heisenberg' model with delta-function repulsions depending on isotropic Heisenberg spin-spin interactions, and indicate that the SFG should be stable against three-body recombination in a large region of the coupling constant plane encompassing parts of both the ferromagnetic and antiferromagnetic phases. However, the limiting case of the fermionic Tonks-Girardeau gas, a spin-aligned 1D Fermi gas with infinitely attractive p-wave interactions, is unstable in this sense. Effects due to the dipolar interaction and a Zeeman term due to a resonance-generating magnetic field do not lead to shrinkage of the region of stability of the SFG

Atmospheric dispersion experiments over complex terrain in a spanish valley site (Guardo-90)

International Nuclear Information System (INIS)

Ibarra, J.I.

1991-01-01

An intensive field experimental campaign was conducted in Spain to quantify atmospheric diffusion within a deep, steep-walled valley in rough, mountainous terrain. The program has been sponsored by the spanish companies of electricity and is intended to validate existing plume models and to provide the scientific basis for future model development. The atmospheric dispersion and transport processes in a 40x40 km domain were studied in order to evaluate SO 2 and SF 6 releases from an existing 185 m chimney and ground level sources in a complex terrain valley site. Emphasis was placed on the local mesoscale flows and light wind stable conditions. Although the measuring program was intensified during daytime for dual tracking of SO 2 /SF 6 from an elevated source, nighttime experiments were conducted for mountain-valley flows characterization. Two principle objectives were pursued: impaction of plumes upon elevated terrain, and diffusion of gases within the valley versus diffusion over flat, open terrain. Artificial smoke flows visualizations provided qualitative information: quantitative diffusion measurements were obtained using sulfur hexafluoride gas with analysis by highly sensitive electron capture gas chromatographs systems. Fourteen 2 hours gaseous tracer releases were conducted

Resource development and the Mackenzie Valley Resource Management Act

International Nuclear Information System (INIS)

Donihee, J.

1999-01-01

Changes to the resource management regime of the Northwest Territories based on land claim agreements with native peoples which result from the Mackenzie Valley Resource Management Act are the result of commitments made by Canada during the negotiation of these land claims. This statute effects important changes to the legislative framework for environmental impact assessment and land and water management. It also establishes land use planning processes for the Gwich'in and Sahtu settlement areas and will result in an environmental and cumulative effects monitoring program for the Mackenzie Valley. The Act also establishes new institutions of public government responsible for environmental impact assessment, land and water management, and land use planning. These boards will play an internal and continuing role in resource development and management in the Mackenzie Valley. A brief overview is included of some features of the new legislative scheme, specifically focussing on environmental impact assessment and water management. An understanding of the new regime will be important for oil and gas companies that are looking north with renewed interest as a result of improved oil and gas prices and also for mining companies given the continuing interest in diamond exploration and development in the Northwest Territories. 29 refs

Systematic Mapping and Statistical Analyses of Valley Landform and Vegetation Asymmetries Across Hydroclimatic Gradients

Science.gov (United States)

Poulos, M. J.; Pierce, J. L.; McNamara, J. P.; Flores, A. N.; Benner, S. G.

2015-12-01

Terrain aspect alters the spatial distribution of insolation across topography, driving eco-pedo-hydro-geomorphic feedbacks that can alter landform evolution and result in valley asymmetries for a suite of land surface characteristics (e.g. slope length and steepness, vegetation, soil properties, and drainage development). Asymmetric valleys serve as natural laboratories for studying how landscapes respond to climate perturbation. In the semi-arid montane granodioritic terrain of the Idaho batholith, Northern Rocky Mountains, USA, prior works indicate that reduced insolation on northern (pole-facing) aspects prolongs snow pack persistence, and is associated with thicker, finer-grained soils, that retain more water, prolong the growing season, support coniferous forest rather than sagebrush steppe ecosystems, stabilize slopes at steeper angles, and produce sparser drainage networks. We hypothesize that the primary drivers of valley asymmetry development are changes in the pedon-scale water-balance that coalesce to alter catchment-scale runoff and drainage development, and ultimately cause the divide between north and south-facing land surfaces to migrate northward. We explore this conceptual framework by coupling land surface analyses with statistical modeling to assess relationships and the relative importance of land surface characteristics. Throughout the Idaho batholith, we systematically mapped and tabulated various statistical measures of landforms, land cover, and hydroclimate within discrete valley segments (n=~10,000). We developed a random forest based statistical model to predict valley slope asymmetry based upon numerous measures (n>300) of landscape asymmetries. Preliminary results suggest that drainages are tightly coupled with hillslopes throughout the region, with drainage-network slope being one of the strongest predictors of land-surface-averaged slope asymmetry. When slope-related statistics are excluded, due to possible autocorrelation, valley

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

Early lessons from the Turner Valley Gas Plant: 'those smoke stacks got a lot of it'

Energy Technology Data Exchange (ETDEWEB)

Finch, D.

2002-06-01

Lessons learned (or not learned) since 1924 in Turner Valley in conjunction with the Royalite No. 4, Alberta's famous runaway well, is told. Initially the gas from this well contained 700 grains of hydrogen sulphide per 100 cubic feet of gas, delivered at such high pressure that no compression was necessary until 1938. Various technologies had been tried to scrub the gas, including a soda ash solution trickled down over a trellis of redwood grids in steel towers, absorbing the hydrogen sulphide. As early as 1925, the plant scrubbed 97 per cent of hydrogen sulphide from 45 million cubic feet of gas per day, making it the largest gas scrubbing plant in the world. However, the hydrogen sulphide scrubbed from the gas stream was being pumped out of twin 123-feet tall towers, and discharged into the atmosphere. At least one death is known to have been caused by the hydrogen sulphide, however, it is suspected that many more deaths have occurred on the ranches and homesteads located downwind from the plant, since people there breathed diluted hydrogen sulphide for 27 years. Royalite finally built a sulphur plant and began manufacturing elemental sulphur from the deadly gas processing byproduct. The issue of flaring has been a matter of serious concern in Alberta for a long time. Governments have made a variety of promises, usually prior to elections, to hold the industry to higher environmental standards, but such promises invariably last only a short time. Sooner or later every government appears to succumb to industry demands; after all, a large part of the provincial economy relies on the oil patch, and a significant portion of the provincial budget comes from direct and indirect taxation of the oil industry, the goose that lays the golden egg. To seriously deal with the issue of flaring, Albertans will need substantial changes in the management of the province.

A fast simulation tool for evaluation of novel well stimulation techniques for tight gas reservoirs

NARCIS (Netherlands)

Egberts, P.J.P.; Peters, E.

2015-01-01

For stimulation of tight fields, alternatives to hydraulic fracturing based on hydraulic jetting are becoming available. With hydraulic jetting many (10 to 20) laterals can be created in a (sub-) vertical well. The laterals are 100 to 200 m long, typically 4 laterals are applied with a small

Detection of gas-permeable fuel particles for highl 7490 temperature gas-cooled reactors

International Nuclear Information System (INIS)

Thiele, B.A.; Stinton, D.P.; Costanzo, D.A.

1980-01-01

Fuel for High-Temperature Gas-Cooled Reactors (HTGR) consists of uranium oxide-carbide and thoria microspheres coated with layers of pyrolytic carbon and silicon carbide. The pyrolytic carbon coatings must be gas-tight to perform properly during irradiation. Therefore, particles must be carefully characterized to determine the number of defective particles (ie bare kernels, and cracked or permeable coatings). Although techniques are available to determine the number of bare kernels or cracked coatings, no reliable technique has been available to measure coating permeability. This work describes a technique recently developed to determine whether coatings for a batch of particles are gas-tight or permeable. Although most of this study was performed on Biso-coated particles, the technique applies equally well to Triso-coated particles. About 150 randomly selected Biso-particle batches were studied in this work. These batches were first subjected to an 18-hr chlorination at 15000C, and the volatile thorium tetrachloride released through cracked or very permeable coatings was measured versus chlorination time. Chlorinated batches were also radiographed to detect any thorium that had migrated from the kernel into the coatings. From this work a technique was developed to determine coating permeability. This consists of an 18-hr chlorination of multiple samples without measurement of the heavy metal released. Each batch is then radiographed and the heavy metal diffusion within each particle is examined so it can be determined if a particle batch is permeable, slightly permeable, or gas-tight. (author)

Experimental Study on Gas Slippage of Tight Gas Sands in Kirthar Fold Belt Sindh, Pakistan

Directory of Open Access Journals (Sweden)

AFTAB AHMEDMAHESAR

2017-07-01

Full Text Available The laboratory experiments on samples from Kirthar fold belt of lower Indus basin Sindh Pakistan were carried out to investigate the effect of gas slippage under varying conditions of pore pressures and overburden stress. The samples were dried in an oven at temperature of 600C and were randomly selected for measurement of permeability and porosity. Permeability was measured using nitrogen gas, while the porosity measurements were made using helium gas expansion porosimeter. The bulk volume was determined by measuring sample diameter and length with caliper. The permeability results suggest that gas slippage increases as if low pore pressures are used, which leads to higher measured permeability than intrinsic permeability of samples. An attempt was also made to estimate the permeability using existing correlations and found that there is large scatter in predicted permeability and measured data. This large amount of scatter in the predicted permeability values concludes that unless absolutely necessary, such correlations should not be used where accurate absolute permeability values are needed. Moreover, the permeability and porosity were plotted together to develop a relation between two properties; the power law fitting of the data well explains the relation between permeability and effective porosity

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

Gas-filled hohlraum fabrication

International Nuclear Information System (INIS)

Salazar, M.A.; Gobby, P.L.; Foreman, L.R.; Bush, H. Jr.; Gomez, V.M.; Moore, J.E.; Stone, G.F.

1995-01-01

Los Alamos National Laboratory (LANL) researchers have fabricated and fielded gas-filled hohlraums at the Lawrence Livermore National Laboratory (LLNL) Nova laser. Fill pressures of 1--5 atmospheres have been typical. We describe the production of the parts, their assembly and fielding. Emphasis is placed on the production of gas-tight polyimide windows and the fielding apparatus and procedure

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.

Hermetic compartments leak-tightness enhancement

International Nuclear Information System (INIS)

Murani, J.

2000-01-01

In connection with the enhancement of the nuclear safety of the Jaslovske Bohunice V-1 NPP actions for the increase of the leak tightness are performed. The reconstruction has been done in the following directions: hermetic compartments leak tightness enhancement; air lock installation; installation of air lock in SP 4 vent system; integrated leakage rate test to hermetic compartments with leak detection. After 'major' leaks on the hermetic boundary components had been eliminated, since 1994 works on a higher qualitative level began. The essence of the works consists in the detection and identification of leaks in the structural component of the hermetic boundary during the planned refueling outages. The results of the Small Reconstruction and gradual enhancement of leak tightness are presented

An Integrated Rock Typing Approach for Unraveling the Reservoir Heterogeneity of Tight Sands in the Whicher Range Field of Perth Basin, Western Australia

DEFF Research Database (Denmark)

Ilkhchi, Rahim Kadkhodaie; Rezaee, Reza; Harami, Reza Moussavi

2014-01-01

Tight gas sands in Whicher Range Field of Perth Basin show large heterogeneity in reservoir characteristics and production behavior related to depositional and diagenetic features. Diagenetic events (compaction and cementation) have severely affected the pore system. In order to investigate...... the petrophysical characteristics, reservoir sandstone facies were correlated with core porosity and permeability and their equivalent well log responses to describe hydraulic flow units and electrofacies, respectively. Thus, very tight, tight, and sub-tight sands were differentiated. To reveal the relationship...... between pore system properties and depositional and diagenetic characteristics in each sand type, reservoir rock types were extracted. The identified reservoir rock types are in fact a reflection of internal reservoir heterogeneity related to pore system properties. All reservoir rock types...

Improving the Availability and Delivery of Critical Information for Tight Gas Resource Development in the Appalachian Basin

Energy Technology Data Exchange (ETDEWEB)

Mary Behling; Susan Pool; Douglas Patchen; John Harper

2008-12-31

To encourage, facilitate and accelerate the development of tight gas reservoirs in the Appalachian basin, the geological surveys in Pennsylvania and West Virginia collected widely dispersed data on five gas plays and formatted these data into a large database that can be accessed by individual well or by play. The database and delivery system that were developed can be applied to any of the 30 gas plays that have been defined in the basin, but for this project, data compilation was restricted to the following: the Mississippian-Devonian Berea/Murrysville sandstone play and the Upper Devonian Venango, Bradford and Elk sandstone plays in Pennsylvania and West Virginia; and the 'Clinton'/Medina sandstone play in northwestern Pennsylvania. In addition, some data were collected on the Tuscarora Sandstone play in West Virginia, which is the lateral equivalent of the Medina Sandstone in Pennsylvania. Modern geophysical logs are the most common and cost-effective tools for evaluating reservoirs. Therefore, all of the well logs in the libraries of the two surveys from wells that had penetrated the key plays were scanned, generating nearly 75,000 scanned e-log files from more than 40,000 wells. A standard file-naming convention for scanned logs was developed, which includes the well API number, log curve type(s) scanned, and the availability of log analyses or half-scale logs. In addition to well logs, other types of documents were scanned, including core data (descriptions, analyses, porosity-permeability cross-plots), figures from relevant chapters of the Atlas of Major Appalachian Gas Plays, selected figures from survey publications, and information from unpublished reports and student theses and dissertations. Monthly and annual production data from 1979 to 2007 for West Virginia wells in these plays are available as well. The final database also includes digitized logs from more than 800 wells, sample descriptions from more than 550 wells, more than 600

Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction.

Science.gov (United States)

Jackson, Robert B; Vengosh, Avner; Darrah, Thomas H; Warner, Nathaniel R; Down, Adrian; Poreda, Robert J; Osborn, Stephen G; Zhao, Kaiguang; Karr, Jonathan D

2013-07-09

Horizontal drilling and hydraulic fracturing are transforming energy production, but their potential environmental effects remain controversial. We analyzed 141 drinking water wells across the Appalachian Plateaus physiographic province of northeastern Pennsylvania, examining natural gas concentrations and isotopic signatures with proximity to shale gas wells. Methane was detected in 82% of drinking water samples, with average concentrations six times higher for homes gas wells (P = 0.0006). Ethane was 23 times higher in homes gas wells (P = 0.0013); propane was detected in 10 water wells, all within approximately 1 km distance (P = 0.01). Of three factors previously proposed to influence gas concentrations in shallow groundwater (distances to gas wells, valley bottoms, and the Appalachian Structural Front, a proxy for tectonic deformation), distance to gas wells was highly significant for methane concentrations (P = 0.007; multiple regression), whereas distances to valley bottoms and the Appalachian Structural Front were not significant (P = 0.27 and P = 0.11, respectively). Distance to gas wells was also the most significant factor for Pearson and Spearman correlation analyses (P gas wells was the only statistically significant factor (P gas (4)He to CH4 in groundwater were characteristic of a thermally postmature Marcellus-like source in some cases. Overall, our data suggest that some homeowners living gas wells have drinking water contaminated with stray gases.

Tightly Coupled Multiphysics Algorithm for Pebble Bed Reactors

International Nuclear Information System (INIS)

Park, HyeongKae; Knoll, Dana; Gaston, Derek; Martineau, Richard

2010-01-01

We have developed a tightly coupled multiphysics simulation tool for the pebble-bed reactor (PBR) concept, a type of Very High-Temperature gas-cooled Reactor (VHTR). The simulation tool, PRONGHORN, takes advantages of the Multiphysics Object-Oriented Simulation Environment library, and is capable of solving multidimensional thermal-fluid and neutronics problems implicitly with a Newton-based approach. Expensive Jacobian matrix formation is alleviated via the Jacobian-free Newton-Krylov method, and physics-based preconditioning is applied to minimize Krylov iterations. Motivation for the work is provided via analysis and numerical experiments on simpler multiphysics reactor models. We then provide detail of the physical models and numerical methods in PRONGHORN. Finally, PRONGHORN's algorithmic capability is demonstrated on a number of PBR test cases.

Mackenzie Gas Project : gas resource and supply study

International Nuclear Information System (INIS)

Harris, D.G.; Braaten, K.M.

2004-01-01

A study was conducted to assess the future gas supply for the Mackenzie Gas Project. The economically recoverable gas resources and deliverability in the region were assessed in order to support construction of the Mackenzie Valley pipeline and the associated gathering system. This supply study was based on a 25 year timeframe for resource development. Production forecasts were also prepared for 50 years following the date of the study. Natural gas forecasts for the general area to be served by the proposed pipeline were also presented. This report includes an introduction to the final gas resource and supply study as well as the regional geology relating to discovered and undiscovered resources. The following regions were included in the study area: onshore Mackenzie Delta including the Niglintgak, Parsons Lake and Taglu anchor fields; central Mackenzie Valley region extending from the Mackenzie Delta south to 63 degrees latitude; northern portion of the Yukon Territory; and, portions of the offshore Mackenzie Delta region limited to a water depth of 30 metres. Forecasts and economic analyses were prepared for the following 3 scenarios: contingent onshore resources only; contingent and prospective onshore resources; and, contingent and prospective onshore and offshore resources. Sensitivity forecasts were prepared for a fully expanded pipeline capacity of 1.8 bcf/day with an equal capacity gathering system. In addition, the National Energy Board estimates of resources for the 3 anchor field were used in place of the operator's estimates. A geological review was included for the plays in the study area. 15 refs., 43 tabs., 38 figs

Panorama 2011: Unconventional gas and water

International Nuclear Information System (INIS)

Vially, R.

2011-01-01

For a number of years now, the rapid development of unconventional gas use in North America has been revolutionising the natural gas market. This generic term refers to several production types, such as tight gas, shale gas and coal bed methane. What they have in common is that the rock needs to be 'stimulated' in order to extract gas from it that can be commercially produced. These methods (horizontal drilling, hydraulic fracturing) all involve sensible management of the water needed for gas production. (author)

Daya Bay Antineutrino Detector Gas System

OpenAIRE

Band, H. R.; Cherwinka, J. J.; Chu, M-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

2012-01-01

The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experimen...

Flow behavior of N2 huff and puff process for enhanced oil recovery in tight oil reservoirs.

Science.gov (United States)

Lu, Teng; Li, Zhaomin; Li, Jian; Hou, Dawei; Zhang, Dingyong

2017-11-16

In the present work, the potential of N 2 huff and puff process to enhance the recovery of tight oil reservoir was evaluated. N 2 huff and puff experiments were performed in micromodels and cores to investigate the flow behaviors of different cycles. The results showed that, in the first cycle, N 2 was dispersed in the oil, forming the foamy oil flow. In the second cycle, the dispersed gas bubbles gradually coalesced into the continuous gas phase. In the third cycle, N 2 was produced in the form of continuous gas phase. The results from the coreflood tests showed that, the primary recovery was only 5.32%, while the recoveries for the three N 2 huff and puff cycles were 15.1%, 8.53% and 3.22%, respectively.The recovery and the pressure gradient in the first cycle were high. With the increase of huff and puff cycles, and the oil recovery and the pressure gradient rapidly decreased. The oil recovery of N 2 huff and puff has been found to increase as the N 2 injection pressure and the soaking time increased. These results showed that, the properly designed and controlled N 2 huff and puff process can lead to enhanced recovery of tight oil reservoirs.

Unconventional gas experience at El Paso Production Company : tapping into deep, tight gas and coalbed methane

International Nuclear Information System (INIS)

Bartley, R.L.

2003-01-01

The current conditions in the natural gas industry were reviewed, from the excellent current and projected energy prices to low activity and rig count. Various graphs were presented, depicting total proved dry gas reserves and annual production over time for the Gulf of Mexico, including its continental shelf, the Texas coastal plains, and the United States lower 48. Offshore growth of unconventional gas was also displayed. The key elements of the strategy were also discussed. These included: (1) earnings driven, (2) superior science, (3) innovative application of technology, (4) ability to act quickly and decisively, (5) leadership, management, and professional development, and (6) achieve learning curve economics. The core competencies were outlined along with recent discoveries in South Texas and the Upper Gulf Coast. figs

A 3D regression surface for the room temperature tightness gasket data reduction and bolt load design

International Nuclear Information System (INIS)

Jolly, Pascal; Marchand, Luc

2008-01-01

The purpose of the present work is to propose a new approach for modelling the tightness behaviour of the gaskets used in bolted flange joints. This new approach consists of developing a mathematical model for a three-dimensional (3D) representation of the gasket tightness performance. Rather than considering a 2D graph for characterizing the complete gasket behaviour, a third axis is added to the S g vs. Tp plot to dissociate the unloading cycles from initial gasket tightening. This leads to the definition of a surface that is represented by a simple polynomial equation that contains six coefficients that are determined by a simple regression calculation. In the first part of the paper, the new approach is tested through a database of 406 room temperature tightness (ROTT) tests performed on different gasket styles. Then, a statistical analysis of the predictions made with the new model demonstrates its ability to predict gasket leak rates much more accurately than it was previously possible with the gasket constants derived from the ROTT Draft 9 or 10 methods. It is also demonstrated that the new approach can be used to model successfully complex gasket behaviours such as the tightness hardening phenomenon. Secondly, the effect of gas pressure change on the leak rate is analysed. It turns out that at high gasket stresses, the actual scheme of the ROTT tests may not allow enough time for reaching a stabilized leak rate value because of a transitory time effect in the porous structure of gaskets. Then, in order to evaluate the characteristic waiting period (dwell time) before a stabilized flow rate is achieved following a change in the gas pressure level, a simple phenomenological analysis of the flow is performed

Tightly Secure Signatures From Lossy Identification Schemes

OpenAIRE

Abdalla , Michel; Fouque , Pierre-Alain; Lyubashevsky , Vadim; Tibouchi , Mehdi

2015-01-01

International audience; In this paper, we present three digital signature schemes with tight security reductions in the random oracle model. Our first signature scheme is a particularly efficient version of the short exponent discrete log-based scheme of Girault et al. (J Cryptol 19(4):463–487, 2006). Our scheme has a tight reduction to the decisional short discrete logarithm problem, while still maintaining the non-tight reduction to the computational version of the problem upon which the or...

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...

Tightness Entropic Uncertainty Relation in Quantum Markovian-Davies Environment

Science.gov (United States)

Zhang, Jun; Liu, Liang; Han, Yan

2018-05-01

In this paper, we investigate the tightness of entropic uncertainty relation in the absence (presence) of the quantum memory which the memory particle being weakly coupled to a decohering Davies-type Markovian environment. The results show that the tightness of the quantum uncertainty relation can be controlled by the energy relaxation time F, the dephasing time G and the rescaled temperature p, the perfect tightness can be arrived by dephasing and energy relaxation satisfying F = 2G and p = 1/2. In addition, the tightness of the memory-assisted entropic uncertainty relation and the entropic uncertainty relation can be influenced mainly by the purity. While in memory-assisted model, the purity and quantum correlation can also influence the tightness actively while the quantum entanglement can influence the tightness slightly.

Study on the pressure self-adaptive water-tight junction box in underwater vehicle

Directory of Open Access Journals (Sweden)

Haocai Huang

2012-09-01

Full Text Available Underwater vehicles play a very important role in underwater engineering. Water-tight junction box (WJB is one of the key components in underwater vehicle. This paper puts forward a pressure self-adaptive water-tight junction box (PSAWJB which improves the reliability of the WJB significantly by solving the sealing and pressure problems in conventional WJB design. By redundancy design method, the pressure self-adaptive equalizer (PSAE is designed in such a way that it consists of a piston pressure-adaptive compensator (PPAC and a titanium film pressure-adaptive compensator (TFPAC. According to hydro-mechanical simulations, the operating volume of the PSAE is more than or equal to 11.6 % of the volume of WJB liquid system. Furthermore, the required operating volume of the PSAE also increases as the gas content of oil, hydrostatic pressure or temperature difference increases. The reliability of the PSAWJB is proved by hyperbaric chamber tests.

Substitution of petroleum liquefied gas for natural gas in a metallurgical industry: a case study; Substituicao de gas liquefeito de petroleo por gas natural em uma siderurgica: um estudo de caso

Energy Technology Data Exchange (ETDEWEB)

Pessoa, Isac Quintao; Miranda, Luciano Lellis; Fullin Junior, Benjamin; Rodrigues, Henrique de Castro; Manella, Roberto [Aperam South America, Timoteo, MG (Brazil). Utilidades e Eficiencia Energetica; Lins, Vanessa de Freitas Cunha [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Quimica

2011-12-21

Minas Gerais is a State where there is no production of natural gas. Aiming to increase the consumption of natural gas in Minas Gerais, PETROBRAS increase the network of gas natural distribution in the State of Minas Gerais and the State concessionaire (GASMIG) installed the Project of Natural Gas Valley. The case study is associated to an enterprise that firmed contract for supplying of natural gas. The fuel to be substituted is the Liquefied Petroleum Gas and the results of the substitution were shown. The advantages of the substitution were related to costs, and environmental aspects with the reduction of CO{sub 2} production. The natural gas contains a lower content of impurities and is operated with higher safety than the petroleum liquefied gas. (author)

In vitro cumulative gas production techniques: history, methodological considerations and challenges

NARCIS (Netherlands)

Rymer, C.; Huntington, J.A.; Williams, B.A.; Givens, D.I.

2005-01-01

Methodology used to measure in vitro gas production is reviewed to determine impacts of sources of variation on resultant gas production profiles (GPP). Current methods include measurement of gas production at constant pressure (e.g., use of gas tight syringes), a system that is inexpensive, but may

A local leaky-box model for the local stellar surface density-gas surface density-gas phase metallicity relation

Science.gov (United States)

Zhu, Guangtun Ben; Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Yan, Renbin; Brinkmann, Jonathan

2017-07-01

We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, gas surface density and gas-phase metallicity, and show that these parameters form a tight relation independent of initial gas density and time. We show that, with canonical values of model parameters, this predicted relation match the observed one well. In addition, we briefly describe a pathway to improving the current semi-analytic models of galaxy formation by incorporating the local leaky-box model in the cosmological context, which can potentially explain simultaneously multiple properties of Milky Way-type disc galaxies, such as the size growth and the global stellar mass-gas metallicity relation.

Graphene rings in magnetic fields: Aharonov–Bohm effect and valley splitting

International Nuclear Information System (INIS)

Wurm, J; Wimmer, M; Richter, K; Baranger, H U

2010-01-01

We study the conductance of mesoscopic graphene rings in the presence of a perpendicular magnetic field by means of numerical calculations based on a tight-binding model. First, we consider the magnetoconductance of such rings and observe the Aharonov–Bohm effect. We investigate different regimes of the magnetic flux up to the quantum Hall regime, where the Aharonov–Bohm oscillations are suppressed. Results for both clean (ballistic) and disordered (diffusive) rings are presented. Second, we study rings with smooth mass boundary that are weakly coupled to leads. We show that the valley degeneracy of the eigenstates in closed graphene rings can be lifted by a small magnetic flux, and that this lifting can be observed in the transport properties of the system

Shale Gas and Oil in Germany - Resources and Environmental Impacts

Science.gov (United States)

Ladage, Stefan; Blumenberg, Martin; Houben, Georg; Pfunt, Helena; Gestermann, Nicolai; Franke, Dieter; Erbacher, Jochen

2017-04-01

In light of the controversial debate on "unconventional" oil and gas resources and the environmental impacts of "fracking", the Federal Institute for Geosciences and Natural Resources (BGR) conducted a comprehensive resource assessment of shale gas and light tight oil in Germany and studied the potential environmental impacts of shale gas development and hydraulic fracturing from a geoscientific perspective. Here, we present our final results (BGR 2016), incorporating the majority of potential shale source rock formations in Germany. Besides shale gas, light tight oil has been assessed. According to our set of criteria - i.e. thermal maturity 0.6-1.2 %vitrinite reflectance (VR; oil) and >1.2 % VR (gas) respectively, organic carbon content > 2%, depth between 500/1000 m and 5000 m as well as a net thickness >20 m - seven potentially generative shale formations were indentified, the most important of them being the Lower Jurassic (Toarcian) Posidonia shale with both shale gas and tight oil potential. The North German basin is by far the most prolific basin. The resource assessment was carried out using a volumetric in-place approach. Variability inherent in the input parameters was accounted for using Monte-Carlo simulations. Technically recoverable resources (TRR) were estimated using recent, production-based recovery factors of North American shale plays and also employing Monte-Carlo simulations. In total, shale gas TRR range between 320 and 2030 bcm and tight oil TRR between 13 and 164 Mio. t in Germany. Tight oil potential is therefore considered minor, whereas the shale gas potential exceeds that of conventional resources by far. Furthermore an overview of numerical transport modelling approaches concerning environmental impacts of the hydraulic fracturing is given. These simulations are based on a representative lithostratigraphy model of the North-German basin, where major shale plays can be expected. Numerical hydrogeological modelling of frac fluid

Future considerations: Imperial finds new promise in natural gas

International Nuclear Information System (INIS)

Martin, J.

1988-01-01

After decades of having natural gas a minor part of its operations, Imperial Oil has reevaluated the importance of that resource within the company's strategy. A comprehensive business review of the industry was conducted in 1987 and prompted Imperial's subsidiary, Esso Resources Canada, to adopt the goal of becoming an industry leader in natural gas reserves, production, and marketing. Imperial's natural gas business started in 1921, when it assumed control of the company whose Turner Valley gas find sparked an oil rush in 1914. By the early 1940s, when Turner Valley was still Canada's only major oil field, Imperial was considering the manufacture of synthetic oil from natural gas, but then it discovered the first well of the Leduc oil boom in 1947. Imperial built the first gas conservation plant in Canada in 1950, but largely left other companies to develop gas fields. The deregulated gas market of the mid-1980s saw Imperial buying its first major acquisition in over 20 years, Sulpetro Ltd.; this boosted Imperial's annual gas production and its reserves by a third. A further purchase of Ocelot Industries increased overall gas production by another 20%. Imperial also made substantial gas finds in the Mackenzie Delta, and the company's holdings at Obed (Alberta) will add 8% to gas production

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.

Regulation of Tight Junctions in Upper Airway Epithelium

Directory of Open Access Journals (Sweden)

Takashi Kojima

2013-01-01

Full Text Available The mucosal barrier of the upper respiratory tract including the nasal cavity, which is the first site of exposure to inhaled antigens, plays an important role in host defense in terms of innate immunity and is regulated in large part by tight junctions of epithelial cells. Tight junction molecules are expressed in both M cells and dendritic cells as well as epithelial cells of upper airway. Various antigens are sampled, transported, and released to lymphocytes through the cells in nasal mucosa while they maintain the integrity of the barrier. Expression of tight junction molecules and the barrier function in normal human nasal epithelial cells (HNECs are affected by various stimuli including growth factor, TLR ligand, and cytokine. In addition, epithelial-derived thymic stromal lymphopoietin (TSLP, which is a master switch for allergic inflammatory diseases including allergic rhinitis, enhances the barrier function together with an increase of tight junction molecules in HNECs. Furthermore, respiratory syncytial virus infection in HNECs in vitro induces expression of tight junction molecules and the barrier function together with proinflammatory cytokine release. This paper summarizes the recent progress in our understanding of the regulation of tight junctions in the upper airway epithelium under normal, allergic, and RSV-infected conditions.

The Role of the Rock on Hydraulic Fracturing of Tight Shales

Science.gov (United States)

Suarez-Rivera, R.; Green, S.; Stanchits, S.; Yang, Y.

2011-12-01

Successful economic production of oil and gas from nano-darcy-range permeability, tight shale reservoirs, is achieved via massive hydraulic fracturing. This is so despite their limited hydrocarbon in place, on per unit rock volume basis. As a reference, consider a typical average porosity of 6% and an average hydrocarbon saturation of 50% to 75%. The importance of tight shales results from their large areal extent and vertical thickness. For example, the areal extent of the Anwar field in Saudi Arabia of 3230 square miles (and 300 ft thick), while the Marcellus shale alone is over 100,000 square miles (and 70 to 150 ft thick). The low permeability of the rock matrix, the predominantly mineralized rock fabric, and the high capillary forces to both brines and hydrocarbons, restrict the mobility of pore fluids in these reservoirs. Thus, one anticipates that fluids do not move very far within tight shales. Successful production, therefore results from maximizing the surface area of contact with the reservoir by massive hydraulic fracturing from horizontal bore holes. This was the conceptual breakthrough of the previous decade and the one that triggered the emergence of gas shales, and recently oily shales, as important economic sources of energy. It is now understood that the process can be made substantially more efficient, more sustainable, and more cost effective by understanding the rock. This will be the breakthrough of this decade. Microseismic monitoring, mass balance calculations, and laboratory experiments of hydraulic fracturing on tight shales indicate the development of fracture complexity and fracture propagation that can not be explained in detail in this layered heterogeneous media. It is now clear that in tight shales the large-scale formation fabric is responsible for fracture complexity. For example, the presence and pervasiveness of mineralized fractures, bed interfaces, lithologic contacts, and other types of discontinuities, and their orientation

21 CFR 173.350 - Combustion product gas.

Science.gov (United States)

2010-04-01

.... Caution. The various parts of the absorption train must be connected by gas-tight tubing and joints... gas source is connected in series to the flow-rate device, the flow meter, and the absorption.... Maintain the coolant bath at 0 °C throughout. Remove the absorption vessel from the bath, disconnect, and...

Natural gas pricing

International Nuclear Information System (INIS)

Freedenthal, C.

1993-01-01

Natural gas pricing is the heart and soul of the gas business. Price specifically affects every phase of the industry. Too low a price will result in short supplies as seen in the mid-1970s when natural gas was scarce and in tight supply. To fully understand the pricing of this energy commodity, it is important to understand the total energy picture. In addition, the effect and impact of world and US economies, and economics in general are crucial to understanding natural gas pricing. The purpose of this presentation will be to show the parameters going into US natural gas pricing including the influence of the many outside industry factors like crude oil and coal pricing, market drivers pushing the gas industry, supply/demand parameters, risk management for buyers and sellers, and other elements involved in pricing analysis

Tunable valley polarization by a gate voltage when an electron tunnels through multiple line defects in graphene.

Science.gov (United States)

Liu, Zhe; Jiang, Liwei; Zheng, Yisong

2015-02-04

By means of an appropriate wave function connection condition, we study the electronic structure of a line defect superlattice of graphene with the Dirac equation method. We obtain the analytical dispersion relation, which can simulate well the tight-binding numerical result about the band structure of the superlattice. Then, we generalize this theoretical method to study the electronic transmission through a potential barrier where multiple line defects are periodically patterned. We find that there exists a critical incident angle which restricts the electronic transmission through multiple line defects within a specific incident angle range. The critical angle depends sensitively on the potential barrier height, which can be modulated by a gate voltage. As a result, non-trivial transmissions of K and K' valley electrons are restricted, respectively, in two distinct ranges of the incident angle. Our theoretical result demonstrates that a gate voltage can act as a feasible measure to tune the valley polarization when electrons tunnel through multiple line defects.

Steam and electroheating remediation of tight soils

Energy Technology Data Exchange (ETDEWEB)

Balshaw-Biddle, K.; Oubre, C.L.; Ward, C.H. [eds.; Dablow, J.F. III; Pearce, J.A.; Johnson, P.C.

2000-07-01

In the past few decades the need for soil remediation has become urgent, even more necessary--innovative, cost effective methods. Steam and Electroheating Remediation of Tight Soils presents the results of a field study testing the cleanup of semi-volatile fuels from tight soils using combination of hydraulic fracturing and soil heating technologies.

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.

Economic and Water Supply Effects of Ending Groundwater Overdraft in California's Central Valley

Directory of Open Access Journals (Sweden)

Timothy Nelson

2016-03-01

Full Text Available doi: http://dx.doi.org/10.15447/sfews.2016v14iss1art7Surface water and groundwater management are often tightly linked, even when linkage is not intended or expected. This link is especially common in semi-arid regions, such as California. This paper summarizes a modeling study on the effects of ending long-term overdraft in California’s Central Valley, the state’s largest aquifer system. The study focuses on economic and operational aspects, such as surface water pumping and diversions, groundwater recharge, water scarcity, and the associated operating and water scarcity costs. This analysis uses CALVIN, a hydro-economic optimization model for California’s water resource system that suggests operational changes to minimize net system costs for a given set of conditions, such as ending long-term overdraft. Based on model results, ending overdraft might induce some major statewide operational changes, including large increases to Delta exports, more intensive conjunctive-use operations with increasing artificial and in-lieu recharge, and greater water scarcity for Central Valley agriculture. The statewide costs of ending roughly 1.2 maf yr-1 of groundwater overdraft are at least $50 million per year from additional direct water shortage and additional operating costs. At its worst, the costs of ending Central Valley overdraft could be much higher, perhaps comparable to the recent economic effects of drought. Driven by recent state legislation to improve groundwater sustainability, ending groundwater overdraft has important implications statewide for water use and management, particularly in the Sacramento–San Joaquin Delta. Ending Central Valley overdraft will amplify economic pressure to increase Delta water exports rather than reduce them, tying together two of California’s largest water management problems.

An introduction to finite tight frames

CERN Document Server

Waldron, Shayne F D

2018-01-01

This textbook is an introduction to the theory and applications of finite tight frames, an area that has developed rapidly in the last decade. Stimulating much of this growth are the applications of finite frames to diverse fields such as signal processing, quantum information theory, multivariate orthogonal polynomials, and remote sensing. Key features and topics: * First book entirely devoted to finite frames * Extensive exercises and MATLAB examples for classroom use * Important examples, such as harmonic and Heisenberg frames, are presented in preliminary chapters, encouraging readers to explore and develop an intuitive feeling for tight frames * Later chapters delve into general theory details and recent research results * Many illustrations showing the special aspects of the geometry of finite frames * Provides an overview of the field of finite tight frames * Discusses future research directions in the field Featuring exercises and MATLAB examples in each chapter, the book is well suited as a textbook ...

Tight or sick building syndrome

Energy Technology Data Exchange (ETDEWEB)

Thirumalaikolundusubramanian, P; Shanmuganadan, S [Madurai Kamaraj Univ. (India). Dept. of Geography; Uma, A [Madurai Medical Coll. (India). Dept. of Medicine and Microbiology

1991-01-01

Modern buildings are designed with the usual heating, air-conditioning and ventilation equipment. In most of these buildings, air is continuously recirculated and, as a result, workers suffer from tight or sick building syndrome. This syndrome is discussed with reference to symptoms of air contamination, ventilation system standards and research needs. The most common symptoms of tight building syndrome are eye, nose and throat irritation, headache, fatigue, sneezing, difficulty in wearing contact lenses, chest tightness, nausea, dizziness and dermatitis. Symptoms experienced by 50 doctors and 50 paramedical personnel working in an air-conditioned intensive care unit and operating theatres of the Government Rajaji Hospital, Madurai in India were studied by means of a questionnaire survey. In the present study, respiratory and ocular symptoms were observed more in those working in operating theatres and were believed to be due to excessive use of formaldehyde used for sterilization. Various suggestions were made to prevent sick building syndrome. Moreover, the physicians treating sick individuals should be aware of the symptoms caused by indoor air pollutants as sufferers invariably require a change of environment rather than drugs. (orig.).

Remote sensing and uranium exploration at Lisbon Valley, Utah

International Nuclear Information System (INIS)

Conel, J.E.; Niesen, P.L.

1981-01-01

Use was made of aircraft-acquired multispectral scanner data to investigate the distribution of bleaching in Wingate sandstone exposed in Lisbon Valley anticline, Utah. All of the large ore bodies contained in lower Chinle Triassic age or Cutler Permian age strate in this area lie beneath or closely adjacent to such bleached outcrops. The distribution of ore bodies and of bleached Wingate strata known from surface outcrops in the Big Indian District are also nearly completely contained within the oil and gas-producing limits of the Lisbon oil and gas and Big Indian gas fields. While there is little direct geologic connection discernible between the surface outcropping sandstones and ore bearing strata, the coincidences suggested this as a possible example of hydrocarbon or sour gas leakage influencing uranium ore deposition and rock alteration in superjacent strata. From a remote sensing point-of-view this study focuses on the distribution of Wingate bleaching. 7 refs

Water management technologies used by Marcellus Shale Gas Producers.

Energy Technology Data Exchange (ETDEWEB)

Veil, J. A.; Environmental Science Division

2010-07-30

Natural gas represents an important energy source for the United States. According to the U.S. Department of Energy's (DOE's) Energy Information Administration (EIA), about 22% of the country's energy needs are provided by natural gas. Historically, natural gas was produced from conventional vertical wells drilled into porous hydrocarbon-containing formations. During the past decade, operators have increasingly looked to other unconventional sources of natural gas, such as coal bed methane, tight gas sands, and gas shales.

Leak-tightness characteristics concerning the containment structures of the HTTR

International Nuclear Information System (INIS)

Sakaba, Nariaki; Iigaki, Kazuhiko; Kondo, Masaaki; Emori, Koichi

2004-01-01

The containment structures of the HTTR consist of the reactor containment vessel, the service area, and the emergency air purification system, which minimise the release of fission products in postulated accidents, which lead to fission product release from the reactor facilities. The reactor containment vessel is designed to withstand the temperature and pressure transients and to be leak-tight in the case of a rupture of the primary concentric hot-gas duct, etc. The pressure inside the service area is maintained at a negative pressure by the emergency air purification system. The emergency air purification system will also remove airborne radioactivity and will maintain a correct pressure in the service area. The leak-tightness characteristics of the containment structures are described in this paper. The measured leakage rates of the reactor containment vessel were enough less than the specified leakage limit of 0.1%/d confirmed during the commissioning tests and annual inspections. The service area was kept in a way that the design pressure becomes well below its allowable limitation by the emergency air purification system, which filters efficiency of particle removal and iodine removal well over the limited values. The obtained data demonstrate that the reactor containment structures were fabricated to minimise the release of fission products in the postulated accidents with fission product release from the reactor facilities

Reliability analysis of hydrologic containment of liquefied petroleum gas within unlined rock caverns.

Science.gov (United States)

Gao, X.; Yan, E. C.; Yeh, T. C. J.; Wang, Y.; Liang, Y.; Hao, Y.

2017-12-01

Notice that most of the underground liquefied petroleum gas (LPG) storage caverns are constructed in unlined rock caverns (URCs), where the variability of hydraulic properties (in particular, hydraulic conductivity) has significant impacts on hydrologic containment performance. However, it is practically impossible to characterize the spatial distribution of these properties in detail at the site of URCs. This dilemma forces us to cope with uncertainty in our evaluations of gas containment. As a consequence, the uncertainty-based analysis is deemed more appropriate than the traditional deterministic analysis. The objectives of this paper are 1) to introduce a numerical first order method to calculate the gas containment reliability within a heterogeneous, two-dimensional unlined rock caverns, and 2) to suggest a strategy for improving the gas containment reliability. In order to achieve these goals, we first introduced the stochastic continuum representation of saturated hydraulic conductivity (Ks) of fractured rock and analyzed the spatial variability of Ks at a field site. We then conducted deterministic simulations to demonstrate the importance of heterogeneity of Ks in the analysis of gas tightness performance of URCs. Considering the uncertainty of the heterogeneity in the real world situations, we subsequently developed a numerical first order method (NFOM) to determine the gas tightness reliability at crucial locations of URCs. Using the NFOM, the effect of spatial variability of Ks on gas tightness reliability was investigated. Results show that as variance or spatial structure anisotropy of Ks increases, most of the gas tightness reliability at crucial locations reduces. Meanwhile, we compare the results of NFOM with those of Monte Carlo simulation, and we find the accuracy of NFOM is mainly affected by the magnitude of the variance of Ks. At last, for improving gas containment reliability at crucial locations at this study site, we suggest that vertical

Dielectric response of molecules in empirical tight-binding theory

Science.gov (United States)

Boykin, Timothy B.; Vogl, P.

2002-01-01

In this paper we generalize our previous approach to electromagnetic interactions within empirical tight-binding theory to encompass molecular solids and isolated molecules. In order to guarantee physically meaningful results, we rederive the expressions for relevant observables using commutation relations appropriate to the finite tight-binding Hilbert space. In carrying out this generalization, we examine in detail the consequences of various prescriptions for the position and momentum operators in tight binding. We show that attempting to fit parameters of the momentum matrix directly generally results in a momentum operator which is incompatible with the underlying tight-binding model, while adding extra position parameters results in numerous difficulties, including the loss of gauge invariance. We have applied our scheme, which we term the Peierls-coupling tight-binding method, to the optical dielectric function of the molecular solid PPP, showing that this approach successfully predicts its known optical properties even in the limit of isolated molecules.

Numerical Modeling of Methane Leakage from a Faulty Natural Gas Well into Fractured Tight Formations.

Science.gov (United States)

Moortgat, Joachim; Schwartz, Franklin W; Darrah, Thomas H

2018-03-01

Horizontal drilling and hydraulic fracturing have enabled hydrocarbon recovery from unconventional reservoirs, but led to natural gas contamination of shallow groundwaters. We describe and apply numerical models of gas-phase migration associated with leaking natural gas wells. Three leakage scenarios are simulated: (1) high-pressure natural gas pulse released into a fractured aquifer; (2) continuous slow leakage into a tilted fractured formation; and (3) continuous slow leakage into an unfractured aquifer with fluvial channels, to facilitate a generalized evaluation of natural gas transport from faulty natural gas wells. High-pressure pulses of gas leakage into sparsely fractured media are needed to produce the extensive and rapid lateral spreading of free gas previously observed in field studies. Transport in fractures explains how methane can travel vastly different distances and directions laterally away from a leaking well, which leads to variable levels of methane contamination in nearby groundwater wells. Lower rates of methane leakage (≤1 Mcf/day) produce shorter length scales of gas transport than determined by the high-pressure scenario or field studies, unless aquifers have low vertical permeabilities (≤1 millidarcy) and fractures and bedding planes have sufficient tilt (∼10°) to allow a lateral buoyancy component. Similarly, in fractured rock aquifers or where permeability is controlled by channelized fluvial deposits, lateral flow is not sufficiently developed to explain fast-developing gas contamination (0-3 months) or large length scales (∼1 km) documented in field studies. Thus, current efforts to evaluate the frequency, mechanism, and impacts of natural gas leakage from faulty natural gas wells likely underestimate contributions from small-volume, low-pressure leakage events. © 2018, National Ground Water Association.

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.

Fission gas retention in irradiated metallic fuel

International Nuclear Information System (INIS)

Fenske, G.R.; Gruber, E.E.; Kramer, J.M.

1987-01-01

Theoretical calculations and experimental measurements of the quantity of retained fission gas in irradiated metallic fuel (U-5Fs) are presented. The calculations utilize the Booth method to model the steady-state release of gases from fuel grains and a simplified grain-boundary gas model to predict the gas release from intergranular regions. The quantity of gas retained in as-irradiated fuel was determined by collecting the gases released from short segments of EBR-II driver fuel that were melted in a gas-tight furnace. Comparison of the calculations to the measurements shows quantitative agreement with both the magnitude and the axial variation of the retained gas content

The Controls of Pore-Throat Structure on Fluid Performance in Tight Clastic Rock Reservoir: A Case from the Upper Triassic of Chang 7 Member, Ordos Basin, China

Directory of Open Access Journals (Sweden)

Yunlong Zhang

2018-01-01

Full Text Available The characteristics of porosity and permeability in tight clastic rock reservoir have significant difference from those in conventional reservoir. The increased exploitation of tight gas and oil requests further understanding of fluid performance in the nanoscale pore-throat network of the tight reservoir. Typical tight sandstone and siltstone samples from Ordos Basin were investigated, and rate-controlled mercury injection capillary pressure (RMICP and nuclear magnetic resonance (NMR were employed in this paper, combined with helium porosity and air permeability data, to analyze the impact of pore-throat structure on the storage and seepage capacity of these tight oil reservoirs, revealing the control factors of economic petroleum production. The researches indicate that, in the tight clastic rock reservoir, largest throat is the key control on the permeability and potentially dominates the movable water saturation in the reservoir. The storage capacity of the reservoir consists of effective throat and pore space. Although it has a relatively steady and significant proportion that resulted from the throats, its variation is still dominated by the effective pores. A combination parameter (ε that was established to be as an integrated characteristic of pore-throat structure shows effectively prediction of physical capability for hydrocarbon resource of the tight clastic rock reservoir.

Fracking in Tight Shales: What Is It, What Does It Accomplish, and What Are Its Consequences?

Science.gov (United States)

Norris, J. Quinn; Turcotte, Donald L.; Moores, Eldridge M.; Brodsky, Emily E.; Rundle, John B.

2016-06-01

Fracking is a popular term referring to hydraulic fracturing when it is used to extract hydrocarbons. We distinguish between low-volume traditional fracking and the high-volume modern fracking used to recover large volumes of hydrocarbons from shales. Shales are fine-grained rocks with low granular permeabilities. During the formation of oil and gas, large fluid pressures are generated. These pressures result in natural fracking, and the resulting fracture permeability allows oil and gas to escape, reducing the fluid pressures. These fractures may subsequently be sealed by mineral deposition, resulting in tight shale formations. The objective of modern fracking is to reopen these fractures and/or create new fractures on a wide range of scales. Modern fracking has had a major impact on the availability of oil and gas globally; however, there are serious environmental objections to modern fracking, which should be weighed carefully against its benefits.

Radon emanation of heterogeneous basin deposits in Kathmandu Valley, Nepal

Science.gov (United States)

Girault, Frédéric; Gajurel, Ananta Prasad; Perrier, Frédéric; Upreti, Bishal Nath; Richon, Patrick

2011-01-01

Effective radium-226 concentration ( EC Ra) has been measured in soil samples from seven horizontal and vertical profiles of terrace scarps in the northern part of Kathmandu Valley, Nepal. The samples belong to the Thimi, Gokarna, and Tokha Formations, dated from 50 to 14 ky BP, and represent a diverse fluvio-deltaic sedimentary facies mainly consisting of gravelly to coarse sands, black, orange and brown clays. EC Ra was measured in the laboratory by radon-222 emanation. The samples ( n = 177) are placed in air-tight glass containers, from which, after an accumulation time varying from 3 to 18 days, the concentration of radon-222, radioactive decay product of radium-226 and radioactive gas with a half-life of 3.8 days, is measured using scintillation flasks. The EC Ra values from the seven different profiles of the terrace deposits vary from 0.4 to 43 Bq kg -1, with profile averages ranging from 12 ± 1 to 27 ± 2 Bq kg -1. The values have a remarkable consistency along a particular horizon of sediment layers, clearly demonstrating that these values can be used for long distance correlations of the sediment horizons. Widely separated sediment profiles, representing similar stratigraphic positions, exhibit consistent EC Ra values in corresponding stratigraphic sediment layers. EC Ra measurements therefore appear particularly useful for lithologic and stratigraphic discriminations. For comparison, EC Ra values of soils from different localities having various sources of origin were also obtained: 9.2 ± 0.4 Bq kg -1 in soils of Syabru-Bensi (Central Nepal), 23 ± 1 Bq kg -1 in red residual soils of the Bhattar-Trisuli Bazar terrace (North of Kathmandu), 17.1 ± 0.3 Bq kg -1 in red residual soils of terrace of Kalikasthan (North of Trisuli Bazar) and 10 ± 1 Bq kg -1 in red residual soils of a site near Nagarkot (East of Kathmandu). The knowledge of EC Ra values for these various soils is important for modelling radon exhalation at the ground surface, in particular

Global Coal Trade. From Tightness to Oversupply

International Nuclear Information System (INIS)

Cornot-Gandolphe, Sylvie

2013-01-01

Over the past four years, international coal trade has been reshaped by China's surging imports. China, which was still a net exporter in 2008, became the world's first coal importer in 2011, taking over the position that Japan has occupied for three decades. Its imports have continued their rising trend and reached a record level in 2012, despite the country's economic slowdown. China imported 289 million tons of coal in 2012, up 30% over 2011. It now accounts for 23% of global imports. Although China is the world's largest coal producer, several factors have contributed to the sudden rise in its imports, including the higher cost of domestic coal relative to international prices and bottlenecks in transporting domestic coal to south-eastern provinces. More recently, another event shook the international coal business: the United States have been back on the market. The collapse of U.S. gas prices, to $4/million Btu in 2011 and even $2.75/million Btu in 2012, linked with the 'shale gas revolution', has made coal uncompetitive in the electricity sector, its main outlet on the U.S. market. U.S. coal demand dropped 4% in 2011 and 11% in 2012. The reduction in domestic demand has forced U.S. miners to look for overseas outlets. Their exports surged by 31% in 2011 and 16% in 2012. They reached 112 million tons in 2012, more than twice the level of 2009. The United States, which almost disappeared from the international steam coal market in the 2000's, have regained a larger share of the total coal export market, 9% in 2012, against 6% in 2009. These developments, although not directly linked, have a huge impact on the global market and pricing of coal. Chinese imports have helped the market to quickly recover from its low level of 2008-2009. The speed and magnitude of China's coal imports even shifts the market from a sluggish to a tight situation. Prices started to rise after their collapse in the second half of 2008 caused by the economic and financial crisis

Centrifugal gas separator

Energy Technology Data Exchange (ETDEWEB)

Sakurai, M

1970-03-27

A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art.

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

Improved Density Functional Tight Binding Potentials for Metalloid Aluminum Clusters

Science.gov (United States)

2016-06-01

unlimited IMPROVED DENSITY-FUNCTIONAL TIGHT BINDING POTENTIALS FOR METALLOID ALUMINUM CLUSTERS by Joon H. Kim June 2016 Thesis Advisor...DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE IMPROVED DENSITY-FUNCTIONAL TIGHT BINDING POTENTIALS FOR METALLOID ALUMINUM CLUSTERS 5. FUNDING...repulsive potentials for use in density-functional tight binding (DFTB) simulations of low-valence aluminum metalloid clusters . These systems are under

Geologic framework for the assessment of undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic-Lower Cretaceous Cotton Valley Group, U.S. Gulf of Mexico region

Science.gov (United States)

Eoff, Jennifer D.; Dubiel, Russell F.; Pearson, Ofori N.; Whidden, Katherine J.

2015-01-01

The U.S. Geological Survey (USGS) is assessing the undiscovered oil and gas resources in sandstone reservoirs of the Upper Jurassic–Lower Cretaceous Cotton Valley Group in onshore areas and State waters of the U.S. Gulf of Mexico region. The assessment is based on geologic elements of a total petroleum system. Four assessment units (AUs) are defined based on characterization of hydrocarbon source and reservoir rocks, seals, traps, and the geohistory of the hydrocarbon products. Strata in each AU share similar stratigraphic, structural, and hydrocarbon-charge histories.

Geology of radon occurrence around Jari in Parvati Valley, Himachal Pradesh, India

International Nuclear Information System (INIS)

Choubey, V.M.; Sharma, K.K.; Ramola, R.C.

1997-01-01

Soil gas and indoor radon concentrations have been measured around Jari in Parvati Valley, Himachal Pradesh, India, to study their relationship with the local geology. Both soil gas and indoor radon concentrations were found to be higher near structurally controlled uranium mineralization. Indoor radon levels in the houses of the study area are considerably higher than the ICRP recommended value of 200 Bq m -3 . The high indoor radon concentration found may be attributed to the geology of the area. This area needs more detailed investigation as it may be one of the areas of high radon risk in India. (Author)

Human zonulin, a potential modulator of intestinal tight junctions.

Science.gov (United States)

Wang, W; Uzzau, S; Goldblum, S E; Fasano, A

2000-12-01

Intercellular tight junctions are dynamic structures involved in vectorial transport of water and electrolytes across the intestinal epithelium. Zonula occludens toxin derived from Vibrio cholerae interacts with a specific intestinal epithelial surface receptor, with subsequent activation of a complex intracellular cascade of events that regulate tight junction permeability. We postulated that this toxin may mimic the effect of a functionally and immunologically related endogenous modulator of intestinal tight junctions. Affinity-purified anti-zonula occludens toxin antibodies and the Ussing chamber assay were used to screen for one or more mammalian zonula occludens toxin analogues in both fetal and adult human intestine. A novel protein, zonulin, was identified that induces tight junction disassembly in non-human primate intestinal epithelia mounted in Ussing chambers. Comparison of amino acids in the active zonula occludens toxin fragment and zonulin permitted the identification of the putative receptor binding domain within the N-terminal region of the two proteins. Zonulin likely plays a pivotal role in tight junction regulation during developmental, physiological, and pathological processes, including tissue morphogenesis, movement of fluid, macromolecules and leukocytes between the intestinal lumen and the interstitium, and inflammatory/autoimmune disorders.

The media of sociology: tight or loose translations?

Science.gov (United States)

Guggenheim, Michael

2015-06-01

Sociologists have increasingly come to recognize that the discipline has unduly privileged textual representations, but efforts to incorporate visual and other media are still only in their beginning. This paper develops an analysis of the ways objects of knowledge are translated into other media, in order to understand the visual practices of sociology and to point out unused possibilities. I argue that the discourse on visual sociology, by assuming that photographs are less objective than text, is based on an asymmetric media-determinism and on a misleading notion of objectivity. Instead, I suggest to analyse media with the concept of translations. I introduce several kinds of translations, most centrally the distinction between tight and loose ones. I show that many sciences, such as biology, focus on tight translations, using a variety of media and manipulating both research objects and representations. Sociology, in contrast, uses both tight and loose translations, but uses the latter only for texts. For visuals, sociology restricts itself to what I call 'the documentary': focusing on mechanical recording technologies without manipulating either the object of research or the representation. I conclude by discussing three rare examples of what is largely excluded in sociology: visual loose translations, visual tight translations based on non-mechanical recording technologies, and visual tight translations based on mechanical recording technologies that include the manipulation of both object and representation. © London School of Economics and Political Science 2015.

A multiple-tracer approach to understanding regional groundwater flow in the Snake Valley area of the eastern Great Basin, USA

International Nuclear Information System (INIS)

Gardner, Philip M.; Heilweil, Victor M.

2014-01-01

Highlights: • Age tracers and noble gases constrain intra- and inter-basin groundwater flow. • Tritium indicates modern (<60 yr) recharge occurring in all mountain areas. • Noble-gas data identify an important interbasin hydraulic discontinuity. • Further groundwater development may significantly impact Snake Valley springs. - Abstract: Groundwater in Snake Valley and surrounding basins in the eastern Great Basin province of the western United States is being targeted for large-scale groundwater extraction and export. Concern about declining groundwater levels and spring flows in western Utah as a result of the proposed groundwater withdrawals has led to efforts that have improved the understanding of this regional groundwater flow system. In this study, environmental tracers (δ 2 H, δ 18 O, 3 H, 14 C, 3 He, 4 He, 20 Ne, 40 Ar, 84 Kr, and 129 Xe) and major ions from 142 sites were evaluated to investigate groundwater recharge and flow-path characteristics. With few exceptions, δ 2 H and δ 18 O show that most valley groundwater has similar ratios to mountain springs, indicating recharge is dominated by relatively high-altitude precipitation. The spatial distribution of 3 H, terrigenic helium ( 4 He terr ), and 3 H/ 3 He ages shows that modern groundwater (<60 yr) in valley aquifers is found only in the western third of the study area. Pleistocene and late-Holocene groundwater is found in the eastern parts of the study area. The age of Pleistocene groundwater is supported by minimum adjusted radiocarbon ages of up to 32 ka. Noble gas recharge temperatures (NGTs) are generally 1–11 °C in Snake and southern Spring Valleys and >11 °C to the east of Snake Valley and indicate a hydraulic discontinuity between Snake and Tule Valleys across the northern Confusion Range. The combination of NGTs and 4 He terr shows that the majority of Snake Valley groundwater discharges as springs, evapotranspiration, and well withdrawals within Snake Valley rather than

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.

Effect of retrograde gas condensate in low permeability natural gas reservoir; Efeito da condensacao retrograda em reservatorios de gas natural com baixa permeabilidade

Energy Technology Data Exchange (ETDEWEB)

Chang, Paulo Lee K.C. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica; Ligero, Eliana L.; Schiozer, Denis J. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Petroleo

2008-07-01

Most of Brazilian gas fields are low-permeability or tight sandstone reservoirs and some of them should be gas condensate reservoir. In this type of natural gas reservoir, part of the gaseous hydrocarbon mixture is condensate and the liquid hydrocarbon accumulates near the well bore that causes the loss of productivity. The liquid hydrocarbon formation inside the reservoir should be well understood such as the knowledge of the variables that causes the condensate formation and its importance in the natural gas production. This work had as goal to better understanding the effect of condensate accumulation near a producer well. The influence of the porosity and the absolute permeability in the gas production was studied in three distinct gas reservoirs: a dry gas reservoir and two gas condensate reservoirs. The refinement of the simulation grid near the producer well was also investigated. The choice of simulation model was shown to be very important in the simulation of gas condensate reservoirs. The porosity was the little relevance in the gas production and in the liquid hydrocarbon formation; otherwise the permeability was very relevant. (author)

Tight fitting garter springs-MODAR

Energy Technology Data Exchange (ETDEWEB)

Kazimer, D. [Bruce Power, Tiverton, Ontario (Canada)

2011-07-01

Annulus spacers are used in CANDU reactors to maintain the annular gap between two tubes - an inner pressure tube (PT) and the outer calandria tube (CT). Typically four annulus spacers are used in one fuel channel assembly, each at a specified axial position. Bruce Unit 8 and many other CANDU units were constructed with tight-fitting garter springs (TFGS). The TFGS were not designed to be detected or relocated by the conventional tool, Spacer Location And Repositioning (SLAR) processes. Due to non-optimal 'As Left' construction locations for the Bruce Unit 8 TFGS, PT/CT contact has been predicted to occur well prior to its End of Life (EOL). Bruce Power entered a Project with AECL-CRL to design, manufacture and test and implement a new tooling system that would detect and reposition tight fitting annulus spacers. (author)

Cataclysmic Rock Avalanche from El Capitan, Yosemite Valley, circa 3.6 ka

Science.gov (United States)

Stock, G. M.

2008-12-01

El Capitan in Yosemite Valley is one of the largest and most iconic granite faces in the world. Despite glacially steepened walls exceeding 90 degrees, a historic database shows relatively few rock falls from El Capitan in the past 150 years. However, a massive bouldery deposit beneath the southeast face suggests an earlier rock avalanche of unusually large size. Spatial analysis of airborne LiDAR data indicate that the rock avalanche deposit has a volume of ~2.70 x 106 m3, a maximum thickness of 18 m, and a runout distance of 660 m, roughly twice the horizontal extent of the adjacent talus. The deposit is very coarse on its distal edge, with individual boulder volumes up to 2500 m3. Cosmogenic 10Be exposure dates from boulders distributed across the deposit confirm this interpretation. Four 10Be samples are tightly clustered between 3.5 and 3.8 ka, with a mean age of 3.6 +/- 0.6 ka. A fifth sample gives a much older age of 22.0 ka, but a glacier occupied Yosemite Valley at this time, prohibiting deposition; thus, the older age likely results from exposure on the cliff face prior to failure. The similarity of ages and overall morphology suggest that the entire deposit formed during a single event. The mean exposure age coincides with inferred Holocene rupture of the northern Owens Valley and/or White Mountain fault(s) between 3.3 and 3.8 ka (Lee et al., 2001; Bacon and Pezzopane, 2007). This time coincidence, combined with the fact that historic rupture of the Owens Valley fault in A.D. 1872 generated numerous large rock falls in Yosemite Valley, strongly suggests that the El Capitan rock avalanche was triggered by a seismic event along the eastern margin of the Sierra Nevada circa 3.6 ka. As there is not an obvious "scar" on the expansive southeast face, the exact source area of the rock avalanche is not yet known. Detrital apatite U-Th/(He) thermochronometry can determine the elevation(s) from which rock fall boulders originate, but significant inter-sample age

Three-dimensional measurement of a tightly focused laser beam

Directory of Open Access Journals (Sweden)

Xiangsheng Xie

2013-02-01

Full Text Available The spatial structure of a tightly focused light field is measured with a double knife-edge scanning method. The measurement method is based on the use of a high-quality double knife-edge fabricated from a right-angled silicon fragment mounted on a photodetector. The reconstruction of the three-dimensional structures of tightly focused spots is carried out with both uniform and partially obstructed linearly polarized incident light beams. The optical field distribution is found to deviate substantially from the input beam profile in the tightly focused region, which is in good agreement with the results of numerical simulations.

76 FR 80553 - Mandatory Reporting of Greenhouse Gases: Technical Revisions to the Petroleum and Natural Gas...

Science.gov (United States)

2011-12-23

... permeability gas, shale gas, coal seam, or other tight reservoir rock. For example, wells producing coal bed... separation means one or more of the following processes: forced extraction of natural gas liquids, sulfur and... Mandatory Reporting of Greenhouse Gases: Technical Revisions to the Petroleum and Natural Gas Systems...

Centrifugal gas separator

International Nuclear Information System (INIS)

Sakurai, Mitsuo.

1970-01-01

A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art. (K.J. Owens)

Proceedings of the CERI 2006 natural gas conference : North American markets : fragile, handle with care

International Nuclear Information System (INIS)

2006-01-01

This conference was attended by decision makers throughout the supply chain in the natural gas industry who face the continuing challenges of changes in market mechanisms, pricing options, and transmission alternatives. It provided an opportunity to review issues affecting producers, shippers, marketers, and end-users in an environment of tight energy markets and high, inelastic demand. The constraints on adequate energy supplies are influenced by economic factors, current and future resources, materials, equipment, skilled labour, technology and financial capital. The 8 sessions of the conference dealt with the tight North American gas supply; the slow development of new supplies; resource access issues, including politics and supply security; the geopolitics of natural gas; impacts of high prices on the North American economy; energy industry impacts of high natural gas prices; domestic politics and high natural gas prices; and, radical planning scenarios for the future of natural gas. The conference featured 23 presentations, of which 6 have been catalogued separately for inclusion in this database. refs., tabs., figs

Striving for equilibrium : the changing role of storage in the North American natural gas industry

International Nuclear Information System (INIS)

Clifton, S.

2003-01-01

This presentation included an analysis of North American storage patterns and transport of natural gas. Gas-fired generation has impacted the value of storage operations significantly. The role of natural gas storage in North America is changing to meet the demands of peak-load generators, to manage tight gas supplies, and expand pipeline infrastructure. Storage facilities help in optimizing the flexibility of gas procurement. The historic role of storage was compared to the current role of storage as an economic asset. In 2002, the major developments affecting gas storage were a decline in liquidity, a decline in North American natural gas production, a recovery in forecasted gas consumption, and a capital dilemma. It is expected that the traditional role of gas storage will intensify as local distribution companies (LDCs) try to manage tight gas supplies, optimize pipeline capacity and manage price volatility. The role of storage as an economic asset will become more prominent and gas storage will be used to meet the needs of power plants. Desirable elements in future storage include a good location, high flexible performance, environmentally secure, and easy to use. The Stagecoach storage facility was presented as a case study. 1 tab., 14 figs

Gas ampoule-syringe

International Nuclear Information System (INIS)

Gay, D.D.

1986-01-01

This patent describes disposable gas ampoule holding or containing a gas such as a radioactive gas, comprising: (a) a cylindrical glass tube which is adapted to hold the gas; (b) a layer of absorbent material which circumscribes and which contacts cylindrical glass tube (a) which absorbs the gas; (c) a plastic tube, which circumscribes and contacts absorbent material layer (b) and which is externally threaded on each of its end portions; (d) a cap, which is threaded onto a first end of plastic tube (c); (e) a cylindrical block, which is positioned in the first end of cylindrical glass tube (a) adjacent to cap (d), which contacts cylindrical glass tube (a), which is composed of a foamed material and which is impregnated with a gas adsorbent material; (f) a cylindrical plunger tip, which is located in the first end of cylindrical glass tube (a) in a gas-tight manner adjacent to cylindrical block (e); (g) an end stopper, which has a central cylindrical shaft that is positioned in the second end of cylindrical glass tube (a); and (h) a cap, which is threaded onto the second end of plastic tube (e). A combination of the disposable gas ampoule and syringe adapted to operably interface with the gas ampoule is also described

Injection of radioactive waste by hydraulic fracturing at West Valley, New York. Volume 2. Text

International Nuclear Information System (INIS)

1978-05-01

Results of a preliminary study are presented of the technical feasibility of radioactive waste disposal by hydraulic fracturing and injection into shale formations below the Nuclear Fuel Services Incorporated site at West Valley, New York. At this time there are approximately 600,000 gallons of high level neutralized Purex waste, including both the supernate (liquid) and sludge, and a further 12,000 gallons of acidic Thorex waste stored in tanks at the West Valley facilities. This study assesses the possibility of combining these wastes in a suitable grout mixture and then injecting them into deep shale formations beneath the West Valley site as a means of permanent disposal. The preliminary feasibility assessment results indicated that at the 850 to 1,250 feet horizons, horizontal fracturing and injection could be effectively achieved. However, a detailed safety analysis is required to establish the acceptability of the degree of isolation. The principal concerns regarding isolation are due to existing and possible future water supply developments within the area and the local effects of the buried valley. In addition, possible future natural gas developments are of concern. The definition of an exclusion zone may be appropriate to avoid problems with these developments. The buried valley may require the injections to be limited to the lower horizon depending on the results of further investigations

Comparative testing of women's tights, which are realized in the Ukrainian market

OpenAIRE

Мартосенко, Марина Григорьевна; Браилко, Анна Сергеевна

2015-01-01

Assortment of women's tights represented on the Ukrainian market is diverse: medical and corrective tights, classic thin and warm, simple and exclusive, ornamental and sports, for pregnant women and moisturizing effect. The size, density, pattern, material composition, visual appearance, matching fashion trends, colors, pricing policy – all these are criteria for the selection of women's tights.With such huge and diverse range of women's tights in the Ukrainian market, the problem of quality ...

Natural gas market assessment. Natural gas supply, western Canada: Recent developments (1982-1992), [and] short-term deliverability outlook (1993-1996)

International Nuclear Information System (INIS)

1993-11-01

A review is presented of the evolution of gas supply from western Canada over the last ten years and a short-term forecast of gas deliverability. To illustrate the changed supply conditions, selected trends and market developments are summarized, including trends in excess deliverability, changes in reserves, the regional distribution of cumulative production, the pace of tieing-in of previously discovered pools for production, the expansion in deliverability from gas storage reservoirs, and recent increases in drilling activity. On the basis of analyses and observations, it is concluded that estimated productive capacity is likely to exceed pipeline capacity on a peak-day basis by a narrow margin over 1993-96. Increasing deliverability from gas storage reservoirs located in the producing provinces is an important factor in handling peak day requirements. From time to time, high demand due to extreme weather conditions could result in pronounced tightness and price fluctuations similar to those seen in winter 1992/93. A strong economic recovery could also result in market tightness, depending on the speed and size of supply response. The growing estimates of resource potential in the western Canada sedimentary basin provide an encouraging indication of the availability of future supply. 29 figs., 3 tabs

Daya Bay Antineutrino Detector gas system

Science.gov (United States)

Band, H. R.; Cherwinka, J. J.; Chu, M.-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

2012-11-01

The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experiment. This constant flush also prevents the infiltration of radon or other contaminants into these detecting liquids keeping the internal backgrounds low. Since the Daya Bay antineutrino detectors are immersed in the large water pools of the muon veto system, other gas volumes are needed to protect vital detector cables or gas lines. These volumes are also purged with dry gas. Return gas is monitored for oxygen content and humidity to provide early warning of potentially damaging leaks. The design and performance of the Daya Bay Antineutrino Detector gas system is described.

Air tightness measurements in older Danish single-family houses

DEFF Research Database (Denmark)

Mortensen, Lone Hedegaard; Bergsøe, Niels Christian

2017-01-01

of the building envelope of older buildings despite the fact that the air tightness has a major influence on the energy use. In connection with renovation of the Danish building stock, the coming years will see increased focus on the air tightness of the building envelope like in other countries. This paper...

Hamstring tightness and Scheuermann's disease a pilot study.

Science.gov (United States)

Fisk, J W; Baigent, M L

1981-06-01

The lateral radiographs of the dorsal spines of 20 patients presenting with mainly low back pain are studied. These patients had clinically evident loss of flexion in the low dorsal spine and very tight hamstring muscles. 85% of them showed definite evidence of previous Scheuermann's Disease. The possibility that tight hamstrings may be an important factor in the aetiology of this disease is discussed, and a further large scale study is proposed.

Valley polarized quantum Hall effect and topological insulator phase transitions in silicene

KAUST Repository

Tahir, M.

2013-01-25

The electronic properties of silicene are distinct from both the conventional two dimensional electron gas and the famous graphene due to strong spin orbit interaction and the buckled structure. Silicene has the potential to overcome limitations encountered for graphene, in particular the zero band gap and weak spin orbit interaction. We demonstrate a valley polarized quantum Hall effect and topological insulator phase transitions. We use the Kubo formalism to discuss the Hall conductivity and address the longitudinal conductivity for elastic impurity scattering in the first Born approximation. We show that the combination of an electric field with intrinsic spin orbit interaction leads to quantum phase transitions at the charge neutrality point, providing a tool to experimentally tune the topological state. Silicene constitutes a model system for exploring the spin and valley physics not accessible in graphene due to the small spin orbit interaction.

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...

Special file: non conventional gases at the origin of the gas financial bubble

International Nuclear Information System (INIS)

2010-01-01

This article discusses the development the non-conventional gas market. For instance, these gases (shale gas, tight gas, coal bed methane or CBM) already represent more than a half of domestic production in the United States, and they may therefore disturb the world market and worsen the overproduction situation. Because of them, liquefied natural gas projects tend to be stopped. The involved technologies are briefly evoked, as well as their profitability

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

Unconventional Tight Reservoirs Characterization with Nuclear Magnetic Resonance

Science.gov (United States)

Santiago, C. J. S.; Solatpour, R.; Kantzas, A.

2017-12-01

The increase in tight reservoir exploitation projects causes producing many papers each year on new, modern, and modified methods and techniques on estimating characteristics of these reservoirs. The most ambiguous of all basic reservoir property estimations deals with permeability. One of the logging methods that is advertised to predict permeability but is always met by skepticism is Nuclear Magnetic Resonance (NMR). The ability of NMR to differentiate between bound and movable fluids and providing porosity increased the capability of NMR as a permeability prediction technique. This leads to a multitude of publications and the motivation of a review paper on this subject by Babadagli et al. (2002). The first part of this presentation is dedicated to an extensive review of the existing correlation models for NMR based estimates of tight reservoir permeability to update this topic. On the second part, the collected literature information is used to analyze new experimental data. The data are collected from tight reservoirs from Canada, the Middle East, and China. A case study is created to apply NMR measurement in the prediction of reservoir characterization parameters such as porosity, permeability, cut-offs, irreducible saturations etc. Moreover, permeability correlations are utilized to predict permeability. NMR experiments were conducted on water saturated cores. NMR T2 relaxation times were measured. NMR porosity, the geometric mean relaxation time (T2gm), Irreducible Bulk Volume (BVI), and Movable Bulk Volume (BVM) were calculated. The correlation coefficients were computed based on multiple regression analysis. Results are cross plots of NMR permeability versus the independently measured Klinkenberg corrected permeability. More complicated equations are discussed. Error analysis of models is presented and compared. This presentation is beneficial in understanding existing tight reservoir permeability models. The results can be used as a guide for choosing

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

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.

Forecasting world natural gas supply

International Nuclear Information System (INIS)

Al-Fattah, S. M.; Startzman, R. A.

2000-01-01

Using the multi-cyclic Hubert approach, a 53 country-specific gas supply model was developed which enables production forecasts for virtually all of the world's gas. Supply models for some organizations such as OPEC, non-OPEC and OECD were also developed and analyzed. Results of the modeling study indicate that the world's supply of natural gas will peak in 2014, followed by an annual decline at the rate of one per cent per year. North American gas production is reported to be currently at its peak with 29 Tcf/yr; Western Europe will reach its peak supply in 2002 with 12 Tcf. According to this forecast the main sources of natural gas supply in the future will be the countries of the former Soviet Union and the Middle East. Between them, they possess about 62 per cent of the world's ultimate recoverable natural gas (4,880 Tcf). It should be noted that these estimates do not include unconventional gas resulting from tight gas reservoirs, coalbed methane, gas shales and gas hydrates. These unconventional sources will undoubtedly play an important role in the gas supply in countries such as the United States and Canada. 18 refs., 2 tabs., 18 figs

THE SLOW DEATH (OR REBIRTH?) OF EXTENDED STAR FORMATION IN z ∼ 0.1 GREEN VALLEY EARLY-TYPE GALAXIES

International Nuclear Information System (INIS)

Fang, Jerome J.; Faber, S. M.; Salim, Samir; Graves, Genevieve J.; Rich, R. Michael

2012-01-01

UV observations in the local universe have uncovered a population of early-type galaxies with UV flux consistent with low-level recent or ongoing star formation. Understanding the origin of such star formation remains an open issue. We present resolved UV-optical photometry of a sample of 19 Sloan Digital Sky Survey (SDSS) early-type galaxies at z ∼ 0.1 drawn from the sample originally selected by Salim and Rich to lie in the bluer part of the green valley in the UV-optical color-magnitude diagram as measured by the Galaxy Evolution Explorer (GALEX). Utilizing high-resolution Hubble Space Telescope (HST) far-UV imaging provides unique insight into the distribution of UV light in these galaxies, which we call ''extended star-forming early-type galaxies'' (ESF-ETGs) because of extended UV emission that is indicative of recent star formation. The UV-optical color profiles of all ESF-ETGs show red centers and blue outer parts. Their outer colors require the existence of a significant underlying population of older stars in the UV-bright regions. An analysis of stacked SDSS spectra reveals weak LINER-like emission in their centers. Using a cross-matched SDSS DR7/GALEX GR6 catalog, we search for other green valley galaxies with similar properties to these ESF-ETGs and estimate that ≈13% of dust-corrected green valley galaxies of similar stellar mass and UV-optical color are likely ESF-candidates, i.e., ESF-ETGs are not rare. Our results are consistent with star formation that is gradually declining in existing disks, i.e., the ESF-ETGs are evolving onto the red sequence for the first time, or with rejuvenated star formation due to accreted gas in older disks provided that the gas does not disrupt the structure of the galaxy and the resulting star formation is not too recent and bursty. ESF-ETGs may typify an important subpopulation of galaxies that can linger in the green valley for up to several Gyrs, based on their resemblance to nearby gas-rich green valley

Design of equipment used for high-level waste vitrification at the West Valley Demonstration Project

International Nuclear Information System (INIS)

Vance, R.F.; Brill, B.A.; Carl, D.E.

1997-06-01

The equipment as designed, started, and operated for high-level radioactive waste vitrification at the West Valley Demonstration Project in western New York State is described. Equipment for the processes of melter feed make-up, vitrification, canister handling, and off-gas treatment are included. For each item of equipment the functional requirements, process description, and hardware descriptions are presented

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.

Advancing New 3D Seismic Interpretation Methods for Exploration and Development of Fractured Tight Gas Reservoirs

Energy Technology Data Exchange (ETDEWEB)

James Reeves

2005-01-31

In a study funded by the U.S. Department of Energy and GeoSpectrum, Inc., new P-wave 3D seismic interpretation methods to characterize fractured gas reservoirs are developed. A data driven exploratory approach is used to determine empirical relationships for reservoir properties. Fractures are predicted using seismic lineament mapping through a series of horizon and time slices in the reservoir zone. A seismic lineament is a linear feature seen in a slice through the seismic volume that has negligible vertical offset. We interpret that in regions of high seismic lineament density there is a greater likelihood of fractured reservoir. Seismic AVO attributes are developed to map brittle reservoir rock (low clay) and gas content. Brittle rocks are interpreted to be more fractured when seismic lineaments are present. The most important attribute developed in this study is the gas sensitive phase gradient (a new AVO attribute), as reservoir fractures may provide a plumbing system for both water and gas. Success is obtained when economic gas and oil discoveries are found. In a gas field previously plagued with poor drilling results, four new wells were spotted using the new methodology and recently drilled. The wells have estimated best of 12-months production indicators of 2106, 1652, 941, and 227 MCFGPD. The latter well was drilled in a region of swarming seismic lineaments but has poor gas sensitive phase gradient (AVO) and clay volume attributes. GeoSpectrum advised the unit operators that this location did not appear to have significant Lower Dakota gas before the well was drilled. The other three wells are considered good wells in this part of the basin and among the best wells in the area. These new drilling results have nearly doubled the gas production and the value of the field. The interpretation method is ready for commercialization and gas exploration and development. The new technology is adaptable to conventional lower cost 3D seismic surveys.

Green River air quality model development: meteorological and tracer data, July/August 1982 field study in Brush Valley, Colorado

Energy Technology Data Exchange (ETDEWEB)

Whiteman, C.D.; Lee, R.N.; Orgill, M.M.; Zak, B.D.

1984-06-01

Meteorological and atmospheric tracer studies were conducted during a 3-week period in July and August of 1982 in the Brush Creek Valley of northwestern Colorado. The objective of the field experiments was to obtain data to evaluate a model, called VALMET, developed at PNL to predict dispersion of air pollutants released from an elevated stack located within a deep mountain valley in the post-sunrise temperature inversion breakup period. Three tracer experiments were conducted in the valley during the 2-week period. In these experiments, sulfur hexafluoride (SF/sub 6/) was released from a height of approximately 100 m, beginning before sunrise and continuing until the nocturnal down-valley winds reversed several hours after sunrise. Dispersion of the sulfur hexafluoride after release was evaluated by measuring SF/sub 6/ concentrations in ambient air samples taken from sampling devices operated within the valley up to about 8 km down valley from the source. An instrumented research aircraft was also used to measure concentrations in and above the valley. Tracer samples were collected using a network of radio-controlled bag sampling stations, two manually operated gas chromatographs, a continuous SF/sub 6/ monitor, and a vertical SF/sub 6/ profiler. In addition, basic meteorological data were collected during the tracer experiments. Frequent profiles of vertical wind and temperature structure were obtained with tethered balloons operated at the release site and at a site 7.7 km down the valley from the release site. 10 references, 63 figures, 50 tables.

Glovebox with purification and pressure control of the neutral gas atmosphere in closed circuit

International Nuclear Information System (INIS)

Cadrot, J.

1990-01-01

In the gas main are placed 2 series of specific gas purifiers in parallel. Pressure is controlled with a buffer tank two three way solenoid value upstream and down stream a compressor and a supercharger. A checking board allows continuous monitoring of circuit tightness [fr

Differences between tight and loose cultures : A 33-nation study

NARCIS (Netherlands)

Gelfand, M.J.; Raver, R.L.; Nishii, L.; Leslie, L.M.; Lun, J.; Lim, B.C.; Van de Vliert, E.

2011-01-01

With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated

Elk Valley Rancheria Energy Efficiency and Alternatives Analysis

Energy Technology Data Exchange (ETDEWEB)

Ed Wait, Elk Valley Rancheria; Frank Ziano & Associates, Inc.

2011-11-30

Elk Valley Rancheria; Tribe; renewable energy; energy options analysis. The Elk Valley Rancheria, California ('Tribe') is a federally recognized Indian tribe located in Del Norte County, California, in the northwestern corner of California. The Tribe, its members and Tribal enterprises are challenged by increasing energy costs and undeveloped local energy resources. The Tribe currently lacks an energy program. The Tribal government lacked sufficient information to make informed decisions about potential renewable energy resources, energy alternatives and other energy management issues. To meet this challenge efficiently, the Tribe contracted with Frank Zaino and Associates, Inc. to help become more energy self-sufficient, by reducing their energy costs and promoting energy alternatives that stimulate economic development. Frank Zaino & Associates, Inc. provided a high level economic screening analysis based on anticipated electric and natural gas rates. This was in an effort to determine which alternative energy system will performed at a higher level so the Tribe could reduce their energy model by 30% from alternative fuel sources. The feasibility study will identify suitable energy alternatives and conservation methods that will benefit the Tribe and tribal community through important reductions in cost. The lessons learned from these conservation efforts will yield knowledge that will serve a wider goal of executing energy efficiency measures and practices in Tribal residences and business facilities. Pacific Power is the provider of electrical power to the four properties under review at $ 0.08 per Kilowatt-hour (KWH). This is a very low energy cost compared to alternative energy sources. The Tribe used baseline audits to assess current and historic energy usage at four Rancheria owned facilities. Past electric and gas billing statements were retained for review for the four buildings that will be audited. A comparative assessment of the various

Winters-Domengine Total Petroleum System—Northern Nonassociated Gas Assessment Unit of the San Joaquin Basin Province: Chapter 21 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

Science.gov (United States)

Hosford Scheirer, Allegra; Magoon, Leslie B.

2008-01-01

The Northern Nonassociated Gas Assessment Unit (AU) of the Winters-Domengine Total Petroleum System of the San Joaquin Basin Province consists of all nonassociated gas accumulations in Cretaceous, Eocene, and Miocene sandstones located north of township 15 South in the San Joaquin Valley. The northern San Joaquin Valley forms a northwest-southeast trending asymmetrical trough. It is filled with an alternating sequence of Cretaceous-aged sands and shales deposited on Franciscan Complex, ophiolitic, and Sierran basement. Eocene-aged strata unconformably overlie the thick Cretaceous section, and in turn are overlain unconformably by nonmarine Pliocene-Miocene sediments. Nonassociated gas accumulations have been discovered in the sands of the Panoche, Moreno, Kreyenhagen, andDomengine Formations and in the nonmarine Zilch formation of Loken (1959) (hereafter referred to as Zilch formation). Most hydrocarbon accumulations occur in low-relief, northwest-southeast trending anticlines formed chiefly by differential compaction of sediment and by northeast southwest directed compression during the Paleogene (Bartow, 1991) and in stratigraphic traps formed by pinch out of submarine fan sands against slope shales. To date, 176 billion cubic feet (BCF) of nonassociated recoverable gas has been found in fields within the assessment unit (table 21.1). A small amount of biogenic gas forms near the surface of the AU. Map boundaries of the assessment unit are shown in figures 21.1 and 21.2; in plan view, this assessment unit is identical to the Northern Area Nonassociated Gas play 1007 considered by the U.S. Geological Survey (USGS) in its 1995 National Assessment (Beyer, 1996). The AU is bounded on the east by the mapped limits of Cretaceous sandstone reservoir rocks and on the west by the east flank of the Diablo Range. The southern limit of the AU is the southernmost occurrence of nonassociated thermogenic-gas accumulations. The northern limit of the AU corresponds to the

Fission gas retention in irradiated metallic fuel

International Nuclear Information System (INIS)

Fenske, G.R.; Gruber, E.; Kramer, J.M.

1987-01-01

Theoretical calculations and experimental measurements of the quantity of retained fission gas in irradiated metallic fuel (U-5 wt. % Fs) are presented. (The symbol 'Fs' designates fissium, a 'pseudo-element' which, in reality, is an alloy whose composition is representative of fission products that remain in reprocessed fuel). The calculations utilize the Booth method to model the steady-state release of gases from fuel grains and a simplified grain-boundary gas model to predict the gas release from intergranular regions. The quantity of gas retained in as-irradiated fuel was determined by collecting the gases released from short segments of EBR-II driver fuel that were melted in a gas-tight furnace. Comparison of the calculations with the measurements shows quantitative agreement in both the magnitude and the axial variation of the retained gas content. (orig.)

Tight Money, Real Interest Rates, and Inflation in Sub-Saharan Africa

OpenAIRE

Edward F. Buffie

2003-01-01

The consequences of tight monetary policy are analyzed in an optimizing currency-substitution model of a small, open economy that operates under an open capital account and a flexible exchange rate. There is a reasonably good fit between the dynamics generated by the model and the stylized facts in the tight-money episodes that occurred in Kenya in 1993 and Nigeria in 1989-91. The study's results shed light on two issues: why tight money has provoked stupendous increases in inflation and the ...

Western Gas Sands Project: stratigrapy of the Piceance Basin

Energy Technology Data Exchange (ETDEWEB)

Anderson, S. (comp.)

1980-08-01

The Western Gas Sands Project Core Program was initiated by US DOE to investigate various low permeability, gas bearing sandstones. Research to gain a better geological understanding of these sandstones and improve evaluation and stimulation techniques is being conducted. Tight gas sands are located in several mid-continent and western basins. This report deals with the Piceance Basin in northwestern Colorado. This discussion is an attempt to provide a general overview of the Piceance Basin stratigraphy and to be a useful reference of stratigraphic units and accompanying descriptions.

Characterization of Gas Transport Properties of Fractured Rocks By Borehole and Chamber Tests.

Science.gov (United States)

Shimo, M.; Shimaya, S.; Maejima, T.

2014-12-01

Gas transport characteristics of fractured rocks is a great concern to variety of engineering applications such as underground storage of LPG, nuclear waste disposal, CCS and gas flooding in the oil field. Besides absolute permeability, relative permeability and capillary pressure as a function of water saturation have direct influences to the results of two phase flow simulation. However, number of the reported gas flow tests for fractured rocks are limited, therefore, the applicability of the conventional two-phase flow functions used for porous media, such as Mualem-van Genuchten model, to prediction of the gas transport in the fractured rock mass are not well understood. The authors conducted the two types of in-situ tests, with different scales, a borehole gas-injection test and a chamber gas-injection test in fractured granitic rock. These tests were conducted in the Cretaceous granitic rocks at the Namikata underground LPG storage cavern construction site in Ehime Prefecture in Japan, preceding to the cavern scale gas-tightness test. A borehole injection test was conducted using vertical and sub-vertical boreholes drilled from the water injection tunnel nearly at the depth of the top of the cavern, EL-150m. A new type downhole gas injection equipment that is capable to create a small 'cavern' within a borehole was developed. After performing a series of preliminary tests to investigate the hydraulic conductivity and gas-tightness, i.e. threshold pressure, gas injection tests were conducted under different gas pressure. Fig.1 shows an example of the test results From a chamber test using a air pressurizing chamber with volume of approximately166m3, the gas-tightness was confirmed within the uncertainty of 22Pa under the storage pressure of 0.7MPa, however, significant air leakage occurred possibly through an open fracture intersecting the chamber just after cavern pressure exceeds the initial hydrostatic pressure at the ceiling level of the chamber. Anomalies

Galaxy and Mass Assembly (GAMA): Morphological transformation of galaxies across the green valley

Science.gov (United States)

Bremer, M. N.; Phillipps, S.; Kelvin, L. S.; De Propris, R.; Kennedy, Rebecca; Moffett, Amanda J.; Bamford, S.; Davies, L. J. M.; Driver, S. P.; Häußler, B.; Holwerda, B.; Hopkins, A.; James, P. A.; Liske, J.; Percival, S.; Taylor, E. N.

2018-05-01

We explore constraints on the joint photometric and morphological evolution of typical low redshift galaxies as they move from the blue cloud through the green valley and on to the red sequence. We select Galaxy And Mass Assembly (GAMA) survey galaxies with 10.25 sensitive K-band profiles of red and green galaxy populations are very similar while g-band profiles indicate more disc-like morphologies for the green galaxies: apparent (optical) morphological differences arise primarily from radial mass-to-light ratio variations. Two-component fits show that most green galaxies have significant bulge and disc components and that the blue to red evolution is driven by colour change in the disc. Together, these strongly suggest that galaxies evolve from blue to red through secular disc fading and that a strong bulge is present prior to any decline in star formation. The relative abundance of the green population implies a typical time-scale for traversing the green valley ˜1-2 Gyr and is independent of environment, unlike that of the red and blue populations. While environment likely plays a rôle in triggering the passage across the green valley, it appears to have little effect on time taken. These results are consistent with a green valley population dominated by (early type) disc galaxies that are insufficiently supplied with gas to maintain previous levels of disc star formation, eventually attaining passive colours. No single event is needed to quench their star formation.

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.

Development of a Gas Systems Analysis Model (GSAM)

International Nuclear Information System (INIS)

Becker, A.B.; Pepper, W.J.

1995-01-01

Objective of developing this model (GSAM) is to create a comprehensive, nonproprietary, PC-based model of domestic gas industry activity. The system can assess impacts of various changes in the natural gas system in North America; individual and collective impacts due to changes in technology and economic conditions are explicitly modeled in GSAM. Major gas resources are all modeled, including conventional, tight, Devonian Shale, coalbed methane, and low-quality gas sources. The modeling system assesses all key components of the gas industry, including available resources, exploration, drilling, completion, production, and processing practices. Distribution, storage, and utilization of natural gas in a dynamic market-gased analytical structure is assessed. GSAM is designed to provide METC managers with a tool to project impacts of future research, development, and demonstration benefits

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.

Exploration practices and prospect of Upper Paleozoic giant gas fields in the Ordos Basin

Directory of Open Access Journals (Sweden)

Shengli Xi

2015-11-01

Full Text Available Natural gas resources is abundant in the Ordos Basin, where six gas fields with more than 100 billion cubic meters of gas reserves have been successively developed and proved, including Jingbian, Yulin, Zizhou, Wushenqi, Sulige and Shenmu. This study aims to summarize the fruitful results and functional practices achieved in the huge gas province exploration, which will be regarded as guidance and reference for the further exploration and development in this basin. Based on the past five decades' successful exploration practices made by PetroChina Changqing Oilfield Company, we first comb the presentation of geological theories at different historical stages as well as the breakthrough in the course. Then, we analyze a complete set of adaptive techniques obtained from the long-time technological research and conclude historical experiences and effective measures in terms of broadening exploration ideas, such as the fluvial delta reservoir-forming theory, giant tight gas reservoir-forming theory, the idea of sediment source system in the southern basin, etc., and innovating technical and management mechanism, such as all-digit seismic prediction, fine logging evaluation for gas formations, stimulation of tight sand reservoirs, flat project and benchmarking management, and so on.

Dressing up history : after nearly two decades of work, the Turner Valley gas plant still isn't ready to take visitors

Energy Technology Data Exchange (ETDEWEB)

Collison, M.

2007-05-15

The abandoned Turner Valley gas plant site near Calgary, Alberta is being turned into a federal and provincial historical site and tourist destination. Alberta Tourism, Parks, Recreation and Culture is protecting and preserving the historical resources of this site because it represents an important period in Alberta's oil and gas processing history, spanning from the mid 1910s through the early 1980s. However, the site also represents more than 7 decades of polluting industrial practices in Alberta. Environmental remediation required to make the site safe for visitors began in 2000 but was halted in 2001 due to general economic uncertainty. Priority orders identified sulphur pollution in the soil, several surface oil spills, mercury in the top 300 mm of soil along with hot spots of mercury near some buildings, hydrocarbon pollution in the upper aquifer of groundwater, asbestos insulation in several buildings and gas seepage near some of the earliest oil wells. Reclamation efforts recommenced in 2005 following floods that exposed contaminated soils and groundwater to the Sheep River. The original goal was to prepare the site as a link in historic sites stretching from the Oil Sands Discovery Centre in Fort McMurray to the Frank Slide Interpretive Centre in Crowsnest Pass. Since industry was not interested in operating a historic site, the site was transferred to government to promote awareness of the history of the oilfields. The reclamation effort has involved building a slurry wall to contain site contamination that could leach into groundwater. A water treatment plant has also been constructed for groundwater to flow before it enters the river. This reclamation effort was compared with that of Cape Breton's Fortress Louisbourg, Canada's largest historical reconstruction. 3 figs.

Fault features and enrichment laws of narrow-channel distal tight sandstone gas reservoirs: A case study of the Jurassic Shaximiao Fm gas reservoir in the Zhongjiang Gas Field, Sichuan Basin

Directory of Open Access Journals (Sweden)

Zhongping Li

2016-11-01

Full Text Available The Jurassic Shaximiao Fm gas reservoir in the Zhongjiang Gas Field, Sichuan Basin, is the main base of Sinopec Southwest Oil & Gas Company for gas reserves and production increase during the 12th Five-Year Plan. However, its natural gas exploration and development process was restricted severely, since the exploration wells cannot be deployed effectively in this area based on the previous gas accumulation and enrichment pattern of “hydrocarbon source fault + channel sand body + local structure”. In this paper, the regional fault features and the gas accumulation and enrichment laws were discussed by analyzing the factors like fault evolution, fault elements, fault-sand body configuration (the configuration relationship between hydrocarbon source faults and channel sand bodies, trap types, and reservoir anatomy. It is concluded that the accumulation and enrichment of the Shaximiao Fm gas reservoir in this area is controlled by three factors, i.e., hydrocarbon source, sedimentary facies and structural position. It follows the accumulation laws of source controlling region, facies controlling zone and position controlling reservoir, which means deep source and shallow accumulation, fault-sand body conductivity, multiphase channel, differential accumulation, adjusted enrichment and gas enrichment at sweet spots. A good configuration relationship between hydrocarbon source faults and channel sand bodies is the basic condition for the formation of gas reservoirs. Natural gas accumulated preferentially in the structures or positions with good fault-sand body configuration. Gas reservoirs can also be formed in the monoclinal structures which were formed after the late structural adjustment. In the zones supported by multiple faults or near the crush zones, no gas accumulation occurs, but water is dominantly produced. The gas-bearing potential is low in the area with undeveloped faults or being 30 km away from the hydrocarbon source faults. So

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.

Fluid inclusion gas chemistry in east Tennessee Mississippi Valley-type districts: Evidence for immiscibility and implications for depositional mechanisms

Energy Technology Data Exchange (ETDEWEB)

Jones, H.D.; Kesler, S.E. (Univ. of Michigan, Ann Arbor (United States))

1992-01-01

Analyses of fluid inclusion gases from Mississippi Valley-type districts in east Tennessee reveal the presence of several distinct aqueous solutions and vapors that were part of the mineralizing process. Inclusion contents were released by crushing 5 to 25 mg mineral samples and by decrepitating individual inclusions; all analyses were obtained by quadrupole mass spectrometry. Most analyzed inclusion fluids consist of H{sub 2}O with significant amounts of CH{sub 4} (0.3 to 2.9 mol%), CO{sub 2} (0.1 to 4.7 mol%), and smaller amounts of C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, H{sub 2}S, SO{sub 2}, N{sub 2}, and Ar. Compositional similarities in the inclusion fluids from three districts imply that mineralization probably formed from fluids that permeated the entire region. Saturation pressures calculated for these fluid compositions range from 300 to 2,200 bars. Burial depths for the host unit have been estimated to be about 2 to 3 km during Devonian time, the age of mineralization indicated by recent isotopic ages. Exsolution of a vapor phase from the mineralizing brines should cause precipitation of carbonate and sulfide minerals, but reaction path modeling indicates that the resulting sparry dolomite:sphalerite ratios would be too high to form an ore-grade deposit. If the vapor phase was from a preexisting sour gas cap that was intercepted by a Zn-rich brine, large amounts of spalerite would precipitate in a fairly small region. Preliminary mass balance calculations suggest that a gas cap of dimensions similar to the individual districts in east Tennessee could have contained enough H{sub 2}S to account for the total amount of sphalerite precipitated.

Fabrication of an electromagnetic pump with gas circulation

International Nuclear Information System (INIS)

Ravoire, J.

1959-01-01

This note reports the design and production of a pump aimed at circulating a gas in a closed circuit, and possessing some specific properties (tightness, gas in contact only with glass, operation pressure range, rates, resistance to overpressure). After a description of pump operation principle, the author describes the glassware part of the pump, its electromagnetic and electronic parts. He reports tests performed to assess pump characteristics. Obtained data are graphically presented, as well as a drawing of the pump

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

Maximize Liquid Oil Production from Shale Oil and Gas Condensate Reservoirs by Cyclic Gas Injection

Energy Technology Data Exchange (ETDEWEB)

Sheng, James [Texas Tech Univ., Lubbock, TX (United States); Li, Lei [Texas Tech Univ., Lubbock, TX (United States); Yu, Yang [Texas Tech Univ., Lubbock, TX (United States); Meng, Xingbang [Texas Tech Univ., Lubbock, TX (United States); Sharma, Sharanya [Texas Tech Univ., Lubbock, TX (United States); Huang, Siyuan [Texas Tech Univ., Lubbock, TX (United States); Shen, Ziqi [Texas Tech Univ., Lubbock, TX (United States); Zhang, Yao [Texas Tech Univ., Lubbock, TX (United States); Wang, Xiukun [Texas Tech Univ., Lubbock, TX (United States); Carey, Bill [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nguyen, Phong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Porter, Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jimenez-Martinez, Joaquin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Viswanathan, Hari [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mody, Fersheed [Apache Corp., Houston, TX (United States); Barnes, Warren [Apache Corp., Houston, TX (United States); Cook, Tim [Apache Corp., Houston, TX (United States); Griffith, Paul [Apache Corp., Houston, TX (United States)

2017-11-17

The current technology to produce shale oil reservoirs is the primary depletion using fractured wells (generally horizontal wells). The oil recovery is less than 10%. The prize to enhance oil recovery (EOR) is big. Based on our earlier simulation study, huff-n-puff gas injection has the highest EOR potential. This project was to explore the potential extensively and from broader aspects. The huff-n-puff gas injection was compared with gas flooding, water huff-n-puff and waterflooding. The potential to mitigate liquid blockage was also studied and the gas huff-n-puff method was compared with other solvent methods. Field pilot tests were initiated but terminated owing to the low oil price and the operator’s budget cut. To meet the original project objectives, efforts were made to review existing and relevant field projects in shale and tight reservoirs. The fundamental flow in nanopores was also studied.

Simulation of thermal stresses in anode-supported solid oxide fuel cell stacks. Part II: Loss of gas-tightness, electrical contact and thermal buckling

Science.gov (United States)

Nakajo, Arata; Wuillemin, Zacharie; Van herle, Jan; Favrat, Daniel

Structural stability issues in planar solid oxide fuel cells arise from the mismatch between the coefficients of thermal expansion of the components. The stress state at operating temperature is the superposition of several contributions, which differ depending on the component. First, the cells accumulate residual stresses due to the sintering phase during the manufacturing process. Further, the load applied during assembly of the stack to ensure electric contact and flatten the cells prevents a completely stress-free expansion of each component during the heat-up. Finally, thermal gradients cause additional stresses in operation. The temperature profile generated by a thermo-electrochemical model implemented in an equation-oriented process modelling tool (gPROMS) was imported into finite-element software (ABAQUS) to calculate the distribution of stress and contact pressure on all components of a standard solid oxide fuel cell repeat unit. The different layers of the cell in exception of the cathode, i.e. anode, electrolyte and compensating layer were considered in the analysis to account for the cell curvature. Both steady-state and dynamic simulations were performed, with an emphasis on the cycling of the electrical load. The study includes two different types of cell, operation under both thermal partial oxidation and internal steam-methane reforming and two different initial thicknesses of the air and fuel compressive sealing gaskets. The results generated by the models are presented in two papers: Part I focuses on cell cracking. In the present paper, Part II, the occurrences of loss of gas-tightness in the compressive gaskets and/or electrical contact in the gas diffusion layer were identified. In addition, the dependence on temperature of both coefficients of thermal expansion and Young's modulus of the metallic interconnect (MIC) were implemented in the finite-element model to compute the plastic deformation, while the possibilities of thermal buckling

Ziff Energy Group's 3. annual 2001+ gas industry outlook

International Nuclear Information System (INIS)

2001-04-01

A survey was conducted in April 2001 regarding industry expectations of gas prices, supply, markets, and transportation. The survey involved 97 participants ranging from gas producers, end-users, marketers, pipeline and local distribution companies in North America. The results of the survey can be summarized as follows: Natural gas prices are expected to grow and remain above oil prices through at least 2002. There will continue to be strong growth prospects for North American gas supply, but North American gas storage will be tight for the winter of 2001. North American gas demand is expected to continue to grow. Participants in the survey remained confident that gas demand would continue to grow, despite higher gas prices. Competition from alternative fuels in electricity generation did not appear to be an area of concern for the participants of the survey. 30 figs

Tightness of M-estimators for multiple linear regression in time series

DEFF Research Database (Denmark)

Johansen, Søren; Nielsen, Bent

We show tightness of a general M-estimator for multiple linear regression in time series. The positive criterion function for the M-estimator is assumed lower semi-continuous and sufficiently large for large argument: Particular cases are the Huber-skip and quantile regression. Tightness requires...

A tightly coupled non-equilibrium model for inductively coupled radio-frequency plasmas

International Nuclear Information System (INIS)

Munafò, A.; Alfuhaid, S. A.; Panesi, M.; Cambier, J.-L.

2015-01-01

The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled system of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients

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.

Local thermal-hydraulic behaviour in tight 7-rod bundles

International Nuclear Information System (INIS)

Cheng, X.; Yu, Y.Q.

2009-01-01

Advanced water-cooled reactor concepts with tight lattices have been proposed worldwide to improve the fuel utilization and the economic competitiveness. In the present work, experimental investigations were performed on thermal-hydraulic behaviour in tight hexagonal 7-rod bundles under both single-phase and two-phase conditions. Freon-12 was used as working fluid due to its convenient operating parameters. Tests were carried out under both single-phase and two-phase flow conditions. Rod surface temperatures are measured at a fixed axial elevation and in various circumferential positions. Test data with different radial power distributions are analyzed. Measured surface temperatures of unheated rods are used for the assessment of and comparison with numerical codes. In addition, numerical simulation using sub-channel analysis code MATRA and the computational fluid dynamics (CFD) code ANSYS-10 is carried out to understand the experimental data and to assess the validity of these codes in the prediction of flow and heat transfer behaviour in tight rod bundle geometries. Numerical results are compared with experimental data. A good agreement between the measured temperatures on the unheated rod surface and the CFD calculation is obtained. Both sub-channel analysis and CFD calculation indicates that the turbulent mixing in the tight rod bundle is significantly stronger than that computed with a well established correlation.

Development of a Simulation Framework for Analyzing Security of Supply in Integrated Gas and Electric Power Systems

NARCIS (Netherlands)

Pambour, Kwabena Addo; Erdener, Burcin Cakir; Bolado-Lavin, Ricardo; Dijkema, Gerhard

2017-01-01

Gas and power networks are tightly coupled and interact with each other due to physically interconnected facilities. In an integrated gas and power network, a contingency observed in one system may cause iterative cascading failures, resulting in network wide disruptions. Therefore, understanding

Experimental study on reflooding in advanced tight lattice PWR

International Nuclear Information System (INIS)

Hori, K.; Kodama, J.; Teramae, T.

2000-01-01

This paper is related to the experimental study on the feasibility of core cooling by re-flooding in a large break loss of coolant accident (LOCA) for the advanced tight lattice pressurized water reactor (PWR). The tight lattice core design should be adopted to improve the conversion ratio. Major one of the key questions of such tight lattice core is the cooling capability under the re-flood condition in a large break LOCA. Forced feed bottom re-flooding experiments have been performed by use of a 4x4 triangular array rod bundle. The rod gap is 0.5 mm, 1.0 mm, or 1.5 mm. The measured peak temperature is below around 1273 K even in case of 1.0/0.5 mm rod gap. And, the evaluation based on the experimental results of rod temperatures and core pressure drop also shows that the core cooling under re-flooding condition is feasible. (author)

Transferable tight-binding model for strained group IV and III-V materials and heterostructures

Science.gov (United States)

Tan, Yaohua; Povolotskyi, Michael; Kubis, Tillmann; Boykin, Timothy B.; Klimeck, Gerhard

2016-07-01

It is critical to capture the effect due to strain and material interface for device level transistor modeling. We introduce a transferable s p3d5s* tight-binding model with nearest-neighbor interactions for arbitrarily strained group IV and III-V materials. The tight-binding model is parametrized with respect to hybrid functional (HSE06) calculations for varieties of strained systems. The tight-binding calculations of ultrasmall superlattices formed by group IV and group III-V materials show good agreement with the corresponding HSE06 calculations. The application of the tight-binding model to superlattices demonstrates that the transferable tight-binding model with nearest-neighbor interactions can be obtained for group IV and III-V materials.

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...

Hydrologic connectivity in the McMurdo Dry Valleys of Antarctica: System function and changes over two decades

Science.gov (United States)

Wlostowski, A. N.; Gooseff, M. N.; Bernzott, E. D.; McKnight, D. M.; Jaros, C.; Lyons, W.

2013-12-01

The McMurdo Dry Valleys of Antarctica is one of the coldest (average annual air temperature of -18°C) and driest (ecological connections in the McMurdo Dry Valleys. Intermittent glacial meltwater streams connect glaciers to closed basin lakes and compose the most prominent hydrologic nexus in the valleys. This study uses of 20+ years of stream temperature, electrical conductivity (EC), and discharge data to enhance our quantitative understanding of the temporal dynamics of hydrologic connections along the glacier-stream-lake continuum. Annually, streamflow occurs for a relatively brief 10-12 week period of the austral summer. Longer streams are more prone to intermittent dry periods during the flow season, making for a harsher ecological environment than shorter streams. Diurnal streamflow variation occurs primarily as a result of changing solar postion relative to the source-glacier surfaces. Therfore, different streams predictably experience high flows and low flows at different times of the day. Electrical conductivity also exhibits diel variations, but the nature of EC-discharge relationships differs among streams throughout the valley. Longer streams have higher EC values and lower discharges than shorter streams, suggesting that hyporheic zones act as a significant solute source and hydrologic reservoir along longer streams. Water temperatures are consistently warmer in longer streams, relative to shorter streams, likely due to prolonged exposure to incident radiation with longer surface water residence times. Inter-annually, several shorter streams in the region show significant increases in Q10, Q30, Q50, Q70, Q90, and/or Q100 flows across the 20+ year record, indicating a long-term non-stationarity in hydrologic system dynamics. The tight coupling between surface waters and the glacier surface energy balance bring forth remarkably consistent hydrologic patterns on the daily and annual timescales, providing a model system for understanding fundamental

Tightness of voter model interfaces

Czech Academy of Sciences Publication Activity Database

Sturm, A.; Swart, Jan M.

2008-01-01

Roč. 13, - (2008), s. 165-174 ISSN 1083-589X R&D Projects: GA ČR GA201/06/1323; GA ČR GA201/07/0237 Institutional research plan: CEZ:AV0Z10750506 Keywords : long range voter model * swapping voter model * interface tightness * exclusion process Subject RIV: BD - Theory of Information Impact factor: 0.392, year: 2008 http://www.emis.de/journals/EJP-ECP/_ejpecp/index.html

Impact of shale gas development on regional water quality.

Science.gov (United States)

Vidic, R D; Brantley, S L; Vandenbossche, J M; Yoxtheimer, D; Abad, J D

2013-05-17

Unconventional natural gas resources offer an opportunity to access a relatively clean fossil fuel that could potentially lead to energy independence for some countries. Horizontal drilling and hydraulic fracturing make the extraction of tightly bound natural gas from shale formations economically feasible. These technologies are not free from environmental risks, however, especially those related to regional water quality, such as gas migration, contaminant transport through induced and natural fractures, wastewater discharge, and accidental spills. We review the current understanding of environmental issues associated with unconventional gas extraction. Improved understanding of the fate and transport of contaminants of concern and increased long-term monitoring and data dissemination will help manage these water-quality risks today and in the future.

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)

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.

Tight turns

CERN Multimedia

Anaïs Schaeffer

2012-01-01

The Italian National Institute for Nuclear Physics (INFN) has successfully tested the first model of a new fast-ramping curved dipole magnet. This is great news for CERN, which sees the advance as holding potential for the future of the SPS.   The first model of a new fast-ramping curved dipole magnet being prepared for cryogenic testing at the LASA laboratory (INFN Milano, Italy). On 16 July INFN introduced an innovative dipole magnet. With a length of some 4 metres, it can produce a 4.5 Tesla magnetic field and achieve a tighter bend than ever before (the bending radius has been squeezed to a remarkable 66.7 metres). This new magnet was designed in the first instance for GSI’s SIS300 synchrotron (in Germany), which will require 60 dipoles of this type. "Achieving such a tight bend demanded a major R&D effort," stressed Pasquale Fabbricatore, the spokesman of the INFN collaboration responsible for the magnet’s development. "We had to not o...

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

Impact of Air Tightness on the Evaluation of Building Energy Performance in Lithuania

Directory of Open Access Journals (Sweden)

Jolanta Šadauskienė

2014-08-01

Full Text Available In order to fulfil the European Energy Performance of Buildings Directive (EPBD requirements for the reduction of energy consumption, European national requirements have been created for building envelope thermal properties and calculation methodology to determine if building energy efficiency is created. This is however not true in all methodologies. The necessity of building air tightness appears only for new A class buildings, and there are no requirements for air tightness for other building classes. Therefore, the aim of this work is to improve the methodology for the calculation of energy efficiency of buildings, while taking into account the air tightness of the buildings. In order to achieve this aim, the sum energy consumption of investigated buildings was calculated, energy efficiency classes were determined, air tightness of the buildings was measured, and reasons for insufficient air tightness were analyzed. Investigation results show that the average value of air tightness of A energy efficiency class buildings is 0.6 h−1. The results of other investigated buildings, corresponding to B and C energy efficiency classes, show insufficient air tightness (the average n50 value is 6 h−1; herewith, energy consumption for heating is higher than calculated, according to the energy efficiency methodology. This paper provides an energy performance evaluation scheme, under which performed evaluation of energy performance of buildings ensures high quality construction work, building durability, and the reliability of heat-loss calculations.

Intestinal epithelial barrier function and tight junction proteins with heat and exercise

DEFF Research Database (Denmark)

Dokladny, Karol; Zuhl, Micah N; Moseley, Pope L

2016-01-01

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or "leaky" intestinal tight junction barrier allows augmented perme...

Water Supply Source Evaluation in Unmanaged Aquifer Recharge Zones: The Mezquital Valley (Mexico Case Study

Directory of Open Access Journals (Sweden)

Antonio Hernández-Espriú

2016-12-01

Full Text Available The Mezquital Valley (MV hosts the largest unmanaged aquifer recharge scheme in the world. The metropolitan area of Mexico City discharges ~60 m3/s of raw wastewater into the valley, a substantial share of which infiltrates into the regional aquifer. In this work, we aim to develop a comprehensive approach, adapted from oil and gas reservoir modeling frameworks, to assess water supply sources located downgradient from unmanaged aquifer recharge zones. The methodology is demonstrated through its application to the Mezquital Valley region. Geological, geoelectrical, petrophysical and hydraulic information is combined into a 3D subsurface model and used to evaluate downgradient supply sources. Although hydrogeochemical variables are yet to be assessed, outcomes suggest that the newly-found groundwater sources may provide a long-term solution for water supply. Piezometric analyses based on 25-year records suggest that the MV is close to steady-state conditions. Thus, unmanaged recharge seems to have been regulating the groundwater balance for the last decades. The transition from unmanaged to managed recharge is expected to provide benefits to the MV inhabitants. It will also be likely to generate new uncertainties in relation to aquifer dynamics and downgradient systems.

Effectiveness of the Solar Panels in the Castro Valley Unified School District Based on Projected Amount of Energy to be Produced

Science.gov (United States)

Sparks, J. R.; Palmer, T. C.; Siegel, A. P.

2014-12-01

In recent years Americans have warmed to the idea of installing solar panels to their homes and businesses. These panels help reduce the cost of receiving energy from power plants that lose a lot of energy in transportation. These power plants provide energy by burning gas or coal producing emissions that add to the growing problem of pollution and global warming. In 2010 the Castro Valley Unified School District decided to add solar panels to Canyon Middle School, Castro Valley High School, and Castro Valley Adult School. We researched whether the solar panels reached their projected amount of energy (74%) for the sites where the panels were placed. The solar panels at all three sites were found to exceed these projected amounts. The solar panels at each site produce a little over 74% for the each school.

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.

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).

Effects of reduced surface tension on two-phase diversion cross-flow between subchannels simplifying triangle tight lattice rod bundle

International Nuclear Information System (INIS)

Kawahara, Akimaro; Sadatomi, Michio; Higuchi, Tatsuya

2009-01-01

Two-phase diversion cross-flow between tight lattice subchannels has been investigated experimentally and analytically. For hydraulically non-equilibrium flows with the pressure difference between the subchannels, experiments were conducted using a vertical multiple-channel with two subchannels simplifying a triangle tight lattice rod bundle. To know the effects of the reduced surface tension on the diversion cross-flow, water and water with a surfactant were used as the test liquids. Data were obtained on the axial variations in the pressure difference between the subchannels, gas and liquid flow rates and void fraction in each subchannel for slug-churn and annular flows. In the analysis, flow redistribution processes due to the diversion cross-flow have been calculated by our subchannel analysis code based on a two-fluid model. From a comparison between the experiment and the code calculation, the code was found to be valid against the present data if the improved constitutive equations of wall and interfacial friction reported in our previous paper were incorporated to account for the reduced surface tension effects. (author)

Microwave emulations and tight-binding calculations of transport in polyacetylene

Energy Technology Data Exchange (ETDEWEB)

Stegmann, Thomas, E-mail: stegmann@icf.unam.mx [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, 62210 Cuernavaca (Mexico); Franco-Villafañe, John A., E-mail: jofravil@fis.unam.mx [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, 72570 Puebla (Mexico); Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, 62210 Cuernavaca (Mexico); Ortiz, Yenni P. [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, 62210 Cuernavaca (Mexico); Kuhl, Ulrich [Université de Nice – Sophia Antipolis, Laboratoire de la Physique de la Matière Condensée, CNRS, Parc Valrose, 06108 Nice (France); Mortessagne, Fabrice, E-mail: fabrice.mortessagne@unice.fr [Université de Nice – Sophia Antipolis, Laboratoire de la Physique de la Matière Condensée, CNRS, Parc Valrose, 06108 Nice (France); Seligman, Thomas H. [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, 62210 Cuernavaca (Mexico); Centro Internacional de Ciencias, 62210 Cuernavaca (Mexico)

2017-01-05

A novel approach to investigate the electron transport of cis- and trans-polyacetylene chains in the single-electron approximation is presented by using microwave emulation measurements and tight-binding calculations. In the emulation we take into account the different electronic couplings due to the double bonds leading to coupled dimer chains. The relative coupling constants are adjusted by DFT calculations. For sufficiently long chains a transport band gap is observed if the double bonds are present, whereas for identical couplings no band gap opens. The band gap can be observed also in relatively short chains, if additional edge atoms are absent, which cause strong resonance peaks within the band gap. The experimental results are in agreement with our tight-binding calculations using the nonequilibrium Green's function method. The tight-binding calculations show that it is crucial to include third nearest neighbor couplings to obtain the gap in the cis-polyacetylene. - Highlights: • Electronic transport in individual polyacetylene chains is studied. • Microwave emulation experiments and tight-binding calculations agree well. • In long chains a band-gap opens due the dimerization of the chain. • In short chains edge atoms cause strong resonance peaks in the center of the band-gap.

Microwave emulations and tight-binding calculations of transport in polyacetylene

International Nuclear Information System (INIS)

Stegmann, Thomas; Franco-Villafañe, John A.; Ortiz, Yenni P.; Kuhl, Ulrich; Mortessagne, Fabrice; Seligman, Thomas H.

2017-01-01

A novel approach to investigate the electron transport of cis- and trans-polyacetylene chains in the single-electron approximation is presented by using microwave emulation measurements and tight-binding calculations. In the emulation we take into account the different electronic couplings due to the double bonds leading to coupled dimer chains. The relative coupling constants are adjusted by DFT calculations. For sufficiently long chains a transport band gap is observed if the double bonds are present, whereas for identical couplings no band gap opens. The band gap can be observed also in relatively short chains, if additional edge atoms are absent, which cause strong resonance peaks within the band gap. The experimental results are in agreement with our tight-binding calculations using the nonequilibrium Green's function method. The tight-binding calculations show that it is crucial to include third nearest neighbor couplings to obtain the gap in the cis-polyacetylene. - Highlights: • Electronic transport in individual polyacetylene chains is studied. • Microwave emulation experiments and tight-binding calculations agree well. • In long chains a band-gap opens due the dimerization of the chain. • In short chains edge atoms cause strong resonance peaks in the center of the band-gap.

The adsorption effect of C6H5 on density of states for double wall carbon nanotubes by tight binding model

International Nuclear Information System (INIS)

Fathalian, A.

2012-01-01

A theoretical approach based on a tight-binding model is developed to study the effects of the adsorption of finite concentrations of C 6 H 5 gas molecules on double-walled carbon nanotube (DWCNT) electronic properties. To obtain proper hopping integrals and random on-site energies for the case of one molecule adsorption, the local density of states for various hopping integrals and random on-site energies are calculated. Since C 6 H 5 molecule is a donor with respect to the carbon nanotubes and their states should appear near the conduction band of the system, effects of various hopping integral deviations and on-site energies for one molecule adsorption are considered to find proper hopping and on-site energies consistent with expected n-type semiconductor. We found that adsorption of C 6 H 5 gas molecules could lead to a (8.0)-(20.0) DWCNT n-type semiconductor. The width of impurity adsorbed gas states in the density of states could be controlled by adsorbed gas concentration.

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

LDA+U and tight-binding electronic structure of InN nanowires

Science.gov (United States)

Molina-Sánchez, A.; García-Cristóbal, A.; Cantarero, A.; Terentjevs, A.; Cicero, G.

2010-10-01

In this paper we employ a combined ab initio and tight-binding approach to obtain the electronic and optical properties of hydrogenated Indium nitride (InN) nanowires. We first discuss InN band structure for the wurtzite structure calculated at the LDA+U level and use this information to extract the parameters needed for an empirical tight-binging implementation. These parameters are then employed to calculate the electronic and optical properties of InN nanowires in a diameter range that would not be affordable by ab initio techniques. The reliability of the large nanowires results is assessed by explicitly comparing the electronic structure of a small diameter wire studied both at LDA+U and tight-binding level.

Active stretching for lower extremity muscle tightness in pediatric patients with lumbar spondylolysis.

Science.gov (United States)

Sato, Masahiro; Mase, Yasuyoshi; Sairyo, Koichi

2017-01-01

It was reported that hamstring muscle tightness may increase mechanical loading on the lumbar spine. Therefore, we attempt to decrease tightness in the leg muscles in pediatric patients. Forty-six pediatric patients with spondylolysis underwent rehabilitation. We applied active stretching to the hamstrings, quadriceps, and triceps surae. Tightness in each muscle was graded as good, fair, or poor. We educated each patient on how to perform active stretching at home. They were re-evaluated for muscle tightness 2 months later. Tightness at baseline and after 2 months was as follows: for the hamstrings, good in 3 patients, fair in 9, and poor in 34 and significant improved after 2 months (p<0.05), with improvement by least 1 grade seen in 86% of patients with fair or poor at baseline; for the quadriceps, 7, 3, and 30 patients had good, fair and poor, with significant improvements in 72% (p<0.05). For the triceps surae, 6, 3 and 10 patients had good, fair and poor, which improved significantly (p<0.05). Home-based active stretching was effective for relieving muscle tightness in the leg in a pediatric population. Adolescent athletes should perform such exercise to maintain flexibility and prevent lumbar disorders. J. Med. Invest. 64: 136-139, February, 2017.

Performance Improvement of Receivers Based on Ultra-Tight Integration in GNSS-Challenged Environments

Directory of Open Access Journals (Sweden)

Feng Qin

2013-12-01

Full Text Available Ultra-tight integration was first proposed by Abbott in 2003 with the purpose of integrating a global navigation satellite system (GNSS and an inertial navigation system (INS. This technology can improve the tracking performances of a receiver by reconfiguring the tracking loops in GNSS-challenged environments. In this paper, the models of all error sources known to date in the phase lock loops (PLLs of a standard receiver and an ultra-tightly integrated GNSS/INS receiver are built, respectively. Based on these models, the tracking performances of the two receivers are compared to verify the improvement due to the ultra-tight integration. Meanwhile, the PLL error distributions of the two receivers are also depicted to analyze the error changes of the tracking loops. These results show that the tracking error is significantly reduced in the ultra-tightly integrated GNSS/INS receiver since the receiver’s dynamics are estimated and compensated by an INS. Moreover, the mathematical relationship between the tracking performances of the ultra-tightly integrated GNSS/INS receiver and the quality of the selected inertial measurement unit (IMU is derived from the error models and proved by the error comparisons of four ultra-tightly integrated GNSS/INS receivers aided by different grade IMUs.

Enforcing dust mass conservation in 3D simulations of tightly coupled grains with the PHANTOM SPH code

Science.gov (United States)

Ballabio, G.; Dipierro, G.; Veronesi, B.; Lodato, G.; Hutchison, M.; Laibe, G.; Price, D. J.

2018-06-01

We describe a new implementation of the one-fluid method in the SPH code PHANTOM to simulate the dynamics of dust grains in gas protoplanetary discs. We revise and extend previously developed algorithms by computing the evolution of a new fluid quantity that produces a more accurate and numerically controlled evolution of the dust dynamics. Moreover, by limiting the stopping time of uncoupled grains that violate the assumptions of the terminal velocity approximation, we avoid fatal numerical errors in mass conservation. We test and validate our new algorithm by running 3D SPH simulations of a large range of disc models with tightly and marginally coupled grains.

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.

Repowering with natural gas

International Nuclear Information System (INIS)

Wilkinson, P.L.

1992-01-01

This chapter examines the concept of combined-cycle repowering with natural gas as one possible solution to the impending dilemma facing electric utilities - tight capacity margins in the 1990s and the inordinate expense of traditional powerplants. Combined-cycle repowering refers to the production of electricity through the integration of new and used equipment at an existing site, with the final equipment configuration resembling a new gas-fired combined-cycle unit (i.e., gas turbine, waste heat recovery unit and steam turbine/generator). Through the utilization of improved waste heat recovery and gas-fired equipment, repowering provides both additional capacity and increased generating efficiency. Three modes of repowering are considered: (1) peak turbine repowering refers to the addition of a steam turbine and heat recovery unit to an existing gas turbine, with the efficiency improvement allowing the unit to convert from peaking to baseload operation; (2) heat recovery repowering is the replacement of an old coal boiler with a gas turbine and heat recovery unit, leaving the existing steam turbine in place; and (3) boiler repowering, in which the exhaust from a new gas turbine is fed into an existing coal boiler, replacing existing forced-draft fans and air heaters. These three options are compared with the option of adding new coal-fired boilers on the basis of economics, energy efficiency and environmental impacts

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

Comparative analysis of efficiency in cooking with natural gas and electricity

International Nuclear Information System (INIS)

Amell Arrieta, Andres; Cadavid Sierra Francisco Javier; Ospina Ospina, Juan Carlos

2001-01-01

The natural gas will have, at the Aburra Valley, a massive application in residential process like heating water and cooking, historically doing with electricity. In the study of electricity substitution in necessary to estimate the gas consumption in order to keep satisfying the energetic requirements at the different strata supposing that, alimentary habits in these have not important valuation through the time. Since the volume of natural gas requirements for the electricity substitution at given conditions depend on electrical energy before substitution, electrical equipment efficiency, gas equipment efficiency and gas substitution heating value, the determination of these efficiencies are necessary. This work presents the calculation processes comparing gas heating and cooking processes, versus electrical devises taking in mind several schemes and essay conditions

Study on water leak-tightness of small leaks on a 1 inch cylinder valve

International Nuclear Information System (INIS)

Miyazawa, T.; Kasai, Y.; Inabe, N.; Aritomi, M.

2002-01-01

Practical thresholds for water leak-tightness of small leaks were determined by experimentation. Measurements for small leak samples were taken of air leakage rates and water leakage rates for identical leak samples in order to identify parameters that influence water leak-tightness threshold. Four types of leaks were evaluated: a fine wire inserted in an O-ring seal, a glass capillary tube, a stainless steel orifice, and a scratched valve stem on a 1 inch UF 6 cylinder valve. Experimental results demonstrated that the key parameter for water leak-tightness is the opening size of the leak hole. The maximum allowable hole size to achieve water leak-tightness ranged from 10 to 20 μm in diameter in this study. Experimental results with 1 inch UF 6 cylinder valve samples demonstrated that the acceptance criteria for preshipment leakage test, 1x10 -3 ref-cm 3 .s -1 , as prescribed in ANSI N14.5 is an appropriate value from the point of view of water leak-tightness for enriched UF 6 packages. The mechanism of water leak-tightness is plugging by tiny particles existing in water. The water used in experiments in this study contained far fewer particles than in water assumed to be encountered under accident conditions of transport. Therefore, the water leak-tightness threshold determined in this study is a conservative value in a practical evaluation. (author)

Nuclear powerplant with closed gas-cooling circuit

International Nuclear Information System (INIS)

Haferkamp, D.; Hodzic, A.; Winter, U.

1976-01-01

Disclosed is a nuclear power plant comprising a pressure-tight safety vessel surrounding the entire plant, an inner vessel of reinforced concrete, a high-temperature reactor contained in the inner vessel, a gas turbine assembly having a turbine and a high- and low-pressure compressor located in a horizontally oriented chamber below the reactor, a plurality of heat exchange units positioned in a plurality of vertically oriented pods spaced radially symmetrically about the reactor and suitable conduits for carrying the reactive gas between the system components. The conduits are arranged in generally horizontally and vertically oriented straight lines, and the conduits for carrying low-pressure gas comprise a horizontal system positioned beneath the turbine assembly having a plurality of coaxial connecting tubes, collectors and distributors as well as normal conduits, so that high pressure gas flows in the internal passage and low-pressure gas flows in the outer passage. 22 claims, 7 figures

Potential effects of geothermal energy conversion on Imperial Valley ecosystems. [Seven workshop presentations

Energy Technology Data Exchange (ETDEWEB)

Shinn, J.H. (ed.)

1976-12-17

This workshop on potential effcts of geothermal energy conversion on the ecology of Imperial Valley brought together personnel of Lawrence Livermore Laboratory and many collaborators under the sponsorship of the ERDA Imperial Valley Environmental Project (IVEP). The LLL Integrated Assessment Team identified the electric power potential and its associated effluents, discharges, subsidence, water requirements, land use, and noise. The Working Groups addressed the ecological problems. Water resource management problems include forces on water use, irrigation methods and water use for crops, water production, and water allocation. Agricultural problems are the contamination of edible crops and the reclamation of soil. A strategy is discussed for predevelopment baseline data and for identification of source term tracers. Wildlife resources might be threatened by habitat destruction, powerline impacts, noise and disturbance effects, gas emissions, and secondary impacts such as population pressure. Aquatic ecosystems in both the Salton Sea and fresh waters have potential hazards of salinity and trace metal effects, as well as existing stresses; baseline and bioassay studies are discussed. Problems from air pollution resulting from geothermal resource development might occur, particularly to vegetation and pollinator insects. Conversion of injury data to predicted economic damage isneeded. Finally, Imperial Valley desert ecosystems might be threatened by destruction of habitat and the possible effects on community structure such as those resulting from brine spills.

Empirical tight-binding parameters for solid C60

International Nuclear Information System (INIS)

Tit, N.; Kumar, V.

1993-01-01

We present a tight-binding model for the electronic structure of C 60 using four (1s and 3p) orbitals per carbon atom. The model has been developed by fitting the tight-binding parameters to the ab-initio pseudopotential calculation of Troullier and Martins (Phys. Rev. B46, 1754 (1992)) in the face-centered cubic (Fm3-bar) phase. Following this, calculations of the energy bands and the density of electronic states have been carried out as a function of the lattice constant. Good agreement has been obtained with the observed lattice-constant dependence of T c using McMillan's formula. Furthermore, calculations of the electronic structure are presented in the simple cubic (Pa3-bar) phase. (author). 43 refs, 3 figs, 1 tab

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

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

Third nearest neighbor parameterized tight binding model for graphene nano-ribbons

Directory of Open Access Journals (Sweden)

Van-Truong Tran

2017-07-01

Full Text Available The existing tight binding models can very well reproduce the ab initio band structure of a 2D graphene sheet. For graphene nano-ribbons (GNRs, the current sets of tight binding parameters can successfully describe the semi-conducting behavior of all armchair GNRs. However, they are still failing in reproducing accurately the slope of the bands that is directly associated with the group velocity and the effective mass of electrons. In this work, both density functional theory and tight binding calculations were performed and a new set of tight binding parameters up to the third nearest neighbors including overlap terms is introduced. The results obtained with this model offer excellent agreement with the predictions of the density functional theory in most cases of ribbon structures, even in the high-energy region. Moreover, this set can induce electron-hole asymmetry as manifested in results from density functional theory. Relevant outcomes are also achieved for armchair ribbons of various widths as well as for zigzag structures, thus opening a route for multi-scale atomistic simulation of large systems that cannot be considered using density functional theory.

The role of technology in unlocking the possibilities of shale gas

CSIR Research Space (South Africa)

Heydenrich, PR

2017-10-01

Full Text Available expelled from the Shale during burial and maturation and so it can be targeted without regard to structural closure. In some cases, a topseal (tight rock) is required Conventional System: Requires trap, or closure Unconventional System: Does... 2. Production of Shale Gas requires: ● Drilling technology capable of horizontal/geosteered well targeting (up to 3000m horizontal length is common) ● Completions technology to optimise the extraction of gas from the formation: ● Temporary...

Leak tight sealants and joint details for concrete structure in RAPP

International Nuclear Information System (INIS)

Singha Roy, P.K.; Baste, M.S.

1975-01-01

Leak tightness may pertain to either air or water and in extreme cases each will require separate consideration based on general basic requirements. Leak-tight sealants against air pressure are required in the construction joints and around penetrations in the concrete containment structures. The containment structures should be able to withstand the maximum anticipated design pressure during the incident of a MCA with only minimal leakage (0.1% of bldg. volume per day in RAPP) which is mostly through these joints. Apart from proper joint design and preparation the sealant itself must have superb adhesion to the concrete surface and integrify throughout its service life to prevent any rupture or micro-cracks at any section of the joint. Leak tightness pertains to water tightness as well. A critical water-tight joint at the bottom dome of the prestressed concrete dousing tank at its junction with the 36 inches dia dousing water pipes constructed in RAPP-2, which should be able to withstand the water pressure, continuous submergence in the water of the tank and the longitudinal and lateral movement of the water pipes during opening and closure of the dousing valves, has been made and hydrostatically tested when not even the slight sweating was found. The construction and materials of the above joints and the sealant along with the properties and performance observed during testing/use are described. As the sealant used is an imported poly-sulphide caulking compound suggestions have also been made, which may be kept in mind while developing an Indian substitute. (author)

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.

Continuous Shearlet Tight Frames

KAUST Repository

Grohs, Philipp

2010-10-22

Based on the shearlet transform we present a general construction of continuous tight frames for L2(ℝ2) from any sufficiently smooth function with anisotropic moments. This includes for example compactly supported systems, piecewise polynomial systems, or both. From our earlier results in Grohs (Technical report, KAUST, 2009) it follows that these systems enjoy the same desirable approximation properties for directional data as the previous bandlimited and very specific constructions due to Kutyniok and Labate (Trans. Am. Math. Soc. 361:2719-2754, 2009). We also show that the representation formulas we derive are in a sense optimal for the shearlet transform. © 2010 Springer Science+Business Media, LLC.

Tight multilattices calculated by extended-cell cylindrization

Energy Technology Data Exchange (ETDEWEB)

Segev, M; Carmona, S

1983-01-01

Among the common features of advanced LWR concepts are the tightness of lattices and the symbiotic setting of different fuels. Such symbioses often come in the form of multilattices, whose numerically-repeated unit is a configuration of several pins, typically with one pin type at the center and pins of a second type surrounding the center pin. If this extended-cell (EC) unit is cylindricized, then a simple transport calculation of the unit will be possible. If the lattice of such units is tight, there is further an a priori reason to expect the cylindrization to introduce only a small distortion of the true neutron fluxes in the lattice. A strict numerical validation of the EC cylindrization approximation is impractical, but similar validations can be carried out for regular lattices, viewed as being made up of multicell units whose centers are moderators and whose peripheries are fuel pins. In these comparisons the EC cylindrization approximation gives good results.

Tight junction regulates epidermal calcium ion gradient and differentiation

International Nuclear Information System (INIS)

Kurasawa, Masumi; Maeda, Tetsuo; Oba, Ai; Yamamoto, Takuya; Sasaki, Hiroyuki

2011-01-01

Research highlights: → We disrupted epidermal tight junction barrier in reconstructed epidermis. → It altered Ca 2+ distribution and consequentially differentiation state as well. → Tight junction should affect epidermal homeostasis by maintaining Ca 2+ gradient. -- Abstract: It is well known that calcium ions (Ca 2+ ) induce keratinocyte differentiation. Ca 2+ distributes to form a vertical gradient that peaks at the stratum granulosum. It is thought that the stratum corneum (SC) forms the Ca 2+ gradient since it is considered the only permeability barrier in the skin. However, the epidermal tight junction (TJ) in the granulosum has recently been suggested to restrict molecular movement to assist the SC as a secondary barrier. The objective of this study was to clarify the contribution of the TJ to Ca 2+ gradient and epidermal differentiation in reconstructed human epidermis. When the epidermal TJ barrier was disrupted by sodium caprate treatment, Ca 2+ flux increased and the gradient changed in ion-capture cytochemistry images. Alterations of ultrastructures and proliferation/differentiation markers revealed that both hyperproliferation and precocious differentiation occurred regionally in the epidermis. These results suggest that the TJ plays a crucial role in maintaining epidermal homeostasis by controlling the Ca 2+ gradient.

Gas laser tube and method of fabricating same

International Nuclear Information System (INIS)

Garman, L.E.

1975-01-01

An improved gas laser tube is fabricated by counter boring the ends of a tubular aluminum extrusion having an inner tubular portion supported from an outer tubular portion via the intermediary of a plurality of radially directed support vanes or legs. Metallic transverse walls are sealed across the ends of the tubular extrusion to define the ends of a gas tight metallic envelope. An electrically insulative glow discharge tube is axially disposed within and supported by the inner tubular portion of the extrusion in axial alignment with an optical resonator of the laser tube. (U.S.)

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.

The oilsands of gas: Massive gas from coal resource being commercialized

Energy Technology Data Exchange (ETDEWEB)

Jaremko, D.

2004-04-05

Gas companies are flocking to Alberta to try their hand in coalbed methane extraction, following EnCana Corporation's success two years ago in launching Canada's first commercial-scale natural gas from coal (NGC) operation. There is an estimated 550 trillion cubic feet of methane gas trapped in Alberta's coal fields, and while current production is still insignificant, the rise in demand for natural gas and the decline in conventional resources makes coalbed methane an increasingly appealing option. In the United States NGC accounts for some 10 per cent of gas production and there is no doubt that the interest expressed by American companies to bring their experience and technology to Alberta is a big factor in pushing the wave of appeal of NGC in the province. The Manville coal deposits, lying between 800 and 1,300 metres below the surface, and the Horseshoe Canyon deposit, about 200 to 500 metres down, are the coal zones of greatest interest in Alberta, while the Elk Valley zone is said to have the greatest potential in British Columbia. The article explains the challenges faced by prospective producers in terms of water disposal, noise abatement, environmental footprint, costs versus benefits, and the various technological alternatives available. Suggestions for involving stakeholders in all aspects of the planning of NGC facilities, and for gaining their support, are also included.

Natural gas market review 2008 - optimising investments and ensuring security in a high-priced environment

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-09-18

Over the last 18 months, natural gas prices have continued to rise steadily in all IEA markets. What are the causes of this steady upward trend? Unprecedented oil and coal prices which have encouraged power generators to switch to gas, together with tight supplies, demand for gas in new markets and delayed investments all played a role. Investment uncertainties, cost increases and delays remain major concerns in most gas markets and are continuing to constitute a threat to long-term security of supply. A massive expansion in LNG production is expected in the short term to 2012, but the lag in LNG investment beyond 2012 is a concern for all gas users in both IEA and non-IEA markets. Despite this tight market context, regional markets continue on their way to globalisation. This tendency seems irreversible, and it impacts even the most independent markets. Price linkages and other interactions between markets are becoming more pronounced. This publication addresses these major developments, assessing investment in natural gas projects (LNG, pipelines, upstream), escalating costs, the activities of international oil and gas companies, and gas demand in the power sector. In addition, the publication includes data and forecasts on OECD and non-OECD regions to 2015 and in-depth reviews of five OECD countries and regions including the European Union. It also provides analysis of 34 non-OECD countries in South America, the Middle East, Africa, and Asia, including a detailed assessment of the outlook for gas in Russia, as well as insights on new technologies to deliver gas to markets.

Gas leak characteristics of inner packaging components used in the D0T-Spec 6M container

International Nuclear Information System (INIS)

Taylor, J.M.

1985-09-01

A test program was conducted by Pacific Northwest Laboratory to determine the gas leak characteristics of metal food pack cans and 2R vessels used to package radioactive material in a D0T 6M specification container. It can be concluded from the tests performed that the inner packaging components (2R vessel, metal product cans) used with a 6M container can be sealed so that they will be gas tight ( -5 cc/sec) under elevated temperature and pressure and impact conditions. To maintain gas tight seals under accident conditions, the metal cans must be sealed with a properly adjusted can-sealing machine; the threads of the 2R vessel must be luted with a sealing compound such as a silicone rubber compound; and the metal cans must be protected inside the 2R vessel with spacer plates and impact absorbers. 4 refs., 37 figs

Chapter 7. The GIS project for the geologic assessment of undiscovered oil and gas in the Cotton Valley group and Travis Peak and Hosston formations, East Texas basin and Louisiana-Mississippi salt basins provinces.

Science.gov (United States)

Biewick, Laura

2006-01-01

A geographic information system (GIS) focusing on the Upper Jurassic-Lower Cretaceous Cotton Valley Group and the Lower Cretaceous Travis Peak and Hosston Formations in the northern Gulf Coast region was developed as a visual-analysis tool for the U.S. Geological Survey's 2002 assessment of undiscovered, technically recoverable oil and natural gas resources in the East Texas Basin and Louisiana-Mississippi Salt Basins Provinces. The Central Energy Resources Team of the U.S. Geological Survey has also developed an Internet Map Service to deliver the GIS data to the public. This mapping tool utilizes information from a database about the oil and natural gas endowment of the United States-including physical locations of geologic and geographic data-and converts the data into visual layers. Portrayal and analysis of geologic features on an interactive map provide an excellent tool for understanding domestic oil and gas resources for strategic planning, formulating economic and energy policies, evaluating lands under the purview of the Federal Government, and developing sound environmental policies. Assessment results can be viewed and analyzed or downloaded from the internet web site, http://energy.cr.usgs.gov/oilgas/noga/ .

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 ...

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.

NGC 404: A REJUVENATED LENTICULAR GALAXY ON A MERGER-INDUCED, BLUEWARD EXCURSION INTO THE GREEN VALLEY

International Nuclear Information System (INIS)

Thilker, David A.; Bianchi, Luciana; Schiminovich, David; Gil de Paz, Armando; Seibert, Mark; Madore, Barry F.; Wyder, Ted; Barlow, Tom; Conrow, Tim; Forster, Karl; Friedman, Peter; Martin, Chris; Morrissey, Patrick; Small, Todd; Rich, R. Michael; Yi, Sukyoung; Neff, Susan

2010-01-01

We have discovered recent star formation in the outermost portion ((1-4) x R 25 ) of the nearby lenticular (S0) galaxy NGC 404 using Galaxy Evolution Explorer UV imaging. FUV-bright sources are strongly concentrated within the galaxy's H I ring (formed by a merger event according to del RIo et al.), even though the average gas density is dynamically subcritical. Archival Hubble Space Telescope imaging reveals resolved upper main-sequence stars and conclusively demonstrates that the UV light originates from recent star formation activity. We present FUV, NUV radial surface brightness profiles, and integrated magnitudes for NGC 404. Within the ring, the average star formation rate (SFR) surface density (Σ SFR ) is ∼2.2 x 10 -5 M sun yr -1 kpc -2 . Of the total FUV flux, 70% comes from the H I ring which is forming stars at a rate of 2.5 x 10 -3 M sun yr -1 . The gas consumption timescale, assuming a constant SFR and no gas recycling, is several times the age of the universe. In the context of the UV-optical galaxy color-magnitude diagram, the presence of the star-forming H I ring places NGC 404 in the green valley separating the red and blue sequences. The rejuvenated lenticular galaxy has experienced a merger-induced, disk-building excursion away from the red sequence toward bluer colors, where it may evolve quiescently or (if appropriately triggered) experience a burst capable of placing it on the blue/star-forming sequence for up to ∼1 Gyr. The green valley galaxy population is heterogeneous, with most systems transitioning from blue to red but others evolving in the opposite sense due to acquisition of fresh gas through various channels.

MODELING OF FLOW AND TRANSPORT INDUCED BY PRODUCTION OF HYDROFRACTURE-STIMULATED GAS WELLS NEAR THE RULISON NUCLEAR TEST

Energy Technology Data Exchange (ETDEWEB)

Hodges, Rex A. [Navarro Research and Engineering; Cooper, Clay [Desert Research Inst. (DRI), Reno, NV (United States); Falta, Ronald [Clemson Univ., SC (United States)

2012-09-17

The Piceance Basin in western Colorado contains significant reserves of natural gas in poorly connected, low-permeability (tight) sandstone lenses of the Mesaverde Group. The ability to enhance the production of natural gas in this area has long been a goal of the oil and gas industry. The U.S. Atomic Energy Commission, a predecessor agency to the U.S. Department of Energy (DOE) and the U.S. Nuclear Regulatory Commission, participated in three tests using nuclear detonations to fracture tight formations in an effort to enhance gas production. The tests were conducted under Project Plowshare, a program designed to identify peaceful, beneficial uses for nuclear devices. The first, Project Gasbuggy, was conducted in 1967 in the San Juan Basin of New Mexico. The two subsequent tests, Project Rulison in 1969 and Project Rio Blanco in 1973, were in the Piceance Basin. The ability to enhance natural gas production from tight sands has become practical through advances in hydraulic fracturing technology (hydrofracturing). This technology has led to an increase in drilling activity near the Rulison site, raising concerns that contamination currently contained in the subsurface could be released through a gas well drilled too close to the site. As wells are drilled nearer the site, the DOE Office of Legacy Management has taken the approach outlined in the June 2010 Rulison Path Forward document (DOE 2010), which recommends a conservative, staged approach to gas development. Drillers are encouraged to drill wells in areas with a low likelihood of encountering contamination (both distance and direction from the detonation zone are factors) and to collect data from these wells prior to drilling nearer the site’s 40 acre institutional control boundary (Lot 11). Previous modeling results indicate that contamination has been contained within Lot 11 (Figure 1). The Path Forward document couples the model predictions with the monitoring of gas and produced water from the gas wells

Injuries and disorders among young ice skaters: relationship with generalized joint laxity and tightness

Directory of Open Access Journals (Sweden)

Okamura S

2014-08-01

Full Text Available Shinobu Okamura,1 Naoki Wada,1 Masayuki Tazawa,1 Makoto Sohmiya,1 Yoko Ibe,1 Toru Shimizu,1 Shigeru Usuda,2 Kenji Shirakura1 1Department of Rehabilitation Medicine, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan; 2Department of Physical Therapy, Gunma University School of Health Science, Maebashi, Gunma, Japan Abstract: This study retrospectively investigated 192 teenage speed and figure skaters with prior injuries documented by an athletes’ questionnaire, who underwent a physical examination to assess their muscle tightness and generalized joint laxity. In all athletes, the degree of muscle tightness and joint laxity were measured by a standardized physical examination. A descriptive report of the types of injuries showed a predominance of fractures, ligament injuries, enthesitis, and lower back pain. Approximately 5% of all skaters tested positive for tightness, while 25.8% of figure skaters and 15.2% of speed skaters had generalized ligamentous laxity. Statistical testing showed an association between ankle sprains and muscle tightness, and an association between knee enthesitis and muscle tightness in skating athletes. There was also an association between lower back pain and generalized joint laxity, which held true only for the male skaters. Keywords: sports injury, skating, junior athlete, tightness, joint laxity, medical checkup

Adaptive tight frame based medical image reconstruction: a proof-of-concept study for computed tomography

International Nuclear Information System (INIS)

Zhou, Weifeng; Cai, Jian-Feng; Gao, Hao

2013-01-01

A popular approach for medical image reconstruction has been through the sparsity regularization, assuming the targeted image can be well approximated by sparse coefficients under some properly designed system. The wavelet tight frame is such a widely used system due to its capability for sparsely approximating piecewise-smooth functions, such as medical images. However, using a fixed system may not always be optimal for reconstructing a variety of diversified images. Recently, the method based on the adaptive over-complete dictionary that is specific to structures of the targeted images has demonstrated its superiority for image processing. This work is to develop the adaptive wavelet tight frame method image reconstruction. The proposed scheme first constructs the adaptive wavelet tight frame that is task specific, and then reconstructs the image of interest by solving an l 1 -regularized minimization problem using the constructed adaptive tight frame system. The proof-of-concept study is performed for computed tomography (CT), and the simulation results suggest that the adaptive tight frame method improves the reconstructed CT image quality from the traditional tight frame method. (paper)

Structural evolution of the virgin spring phase of the amargosa chaos, Death Valley, California, USA

Science.gov (United States)

Castonguay, Samuel Robert

The Amargosa Chaos and Fault of Death Valley are complex features that play important roles in various tectonic models. Some recent models claim the fault is a regional detachment accommodating 80 km of NW-directed transport that produced the Chaos in its hangingwall. I offer an alternative interpretation: the chaos is a product of multiphase deformation that likely spanned the late Mesozoic and Cenozoic. The Amargosa Fault represents just one of six deformation events. The accompanying map (supplemental file) shows the cross-cutting relationships among fault populations: (D1) 25% north-northwest directed shortening across an imbricate thrust and tight fold system; (D2) E-SE extension on five normal faults; (D3) extension-related folding, which folded the D2 faults; (D4) normal-oblique slip on the Amargosa Fault; (D5) E-W extension on domino faults; (D6) extension on the Black Mountains Frontal Fault. The D2 faults, not the Amargosa, created the enigmatic attenuation observed in the Chaos.

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

Energy Technology Data Exchange (ETDEWEB)

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 CO{sub 2} emission result was 13,894.9 Gg, which constituted three-quarters of Hidalgo statewide energy category. The principal CO{sub 2} 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-CO{sub 2} gas emissions were also significant, particularly SO{sub 2} (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. - Highlights: • First GHG & black carbon inventory for Mezquital Valley: Mexico City energy supplier • Energy industries caused the largest CO{sub 2} and SO{sub 2} emissions from residual fuel oil. • Diesel

Nonlinear Filtering with IMM Algorithm for Ultra-Tight GPS/INS Integration

Directory of Open Access Journals (Sweden)

Dah-Jing Jwo

2013-05-01

Full Text Available Abstract This paper conducts a performance evaluation for the ultra-tight integration of a Global positioning system (GPS and an inertial navigation system (INS, using nonlinear filtering approaches with an interacting multiple model (IMM algorithm. An ultra-tight GPS/INS architecture involves the integration of in-phase and quadrature components from the correlator of a GPS receiver with INS data. An unscented Kalman filter (UKF, which employs a set of sigma points by deterministic sampling, avoids the error caused by linearization as in an extended Kalman filter (EKF. Based on the filter structural adaptation for describing various dynamic behaviours, the IMM nonlinear filtering provides an alternative for designing the adaptive filter in the ultra-tight GPS/INS integration. The use of IMM enables tuning of an appropriate value for the process of noise covariance so as to maintain good estimation accuracy and tracking capability. Two examples are provided to illustrate the effectiveness of the design and demonstrate the effective improvement in navigation estimation accuracy. A performance comparison among various filtering methods for ultra-tight integration of GPS and INS is also presented. The IMM based nonlinear filtering approach demonstrates the effectiveness of the algorithm for improved positioning performance.

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.

Equiangular tight frames and unistochastic matrices

Czech Academy of Sciences Publication Activity Database

Goyeneche, D.; Turek, Ondřej

2017-01-01

Roč. 50, č. 24 (2017), č. článku 245304. ISSN 1751-8113 R&D Projects: GA ČR GA17-01706S Institutional support: RVO:61389005 Keywords : equiangular tight frames * unistochastic matrices * SIC POVM Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 1.857, year: 2016

Surface Passivation in Empirical Tight Binding

OpenAIRE

He, Yu; Tan, Yaohua; Jiang, Zhengping; Povolotskyi, Michael; Klimeck, Gerhard; Kubis, Tillmann

2015-01-01

Empirical Tight Binding (TB) methods are widely used in atomistic device simulations. Existing TB methods to passivate dangling bonds fall into two categories: 1) Method that explicitly includes passivation atoms is limited to passivation with atoms and small molecules only. 2) Method that implicitly incorporates passivation does not distinguish passivation atom types. This work introduces an implicit passivation method that is applicable to any passivation scenario with appropriate parameter...

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.

On tight multiparty Bell inequalities for many settings

OpenAIRE

Zukowski, Marek

2006-01-01

A derivation method is given which leads to a series of tight Bell inequalities for experiments involving N parties, with binary observables, and three possible local settings. The approach can be generalized to more settings. Ramifications are presented.

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.

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.

Application of radiotracer method for tightness control and leakage localization in industrial objects

International Nuclear Information System (INIS)

Kras, J; Walis, L.; Myczkowski, S.

2001-01-01

Application of 82 Br in the form of gaseous CH 3 Br for tightness control and leakage localization in large industrial apparatus as chemical reactors, columns, vessels, pipelines etc. has been presented. The tracer has been prepared at the place of measurements in a specially designed mobile chemical reactor. The paper presents different variants of the method convenient for: tightness control of underground pipelines, leakage control of technological objects working in chemical and petrochemical industry, tightness control of large metal vessels localized underground and on surface. The radiometric devices used in mentioned variants have ben performed as well

Extended Lagrangian formulation of charge-constrained tight-binding molecular dynamics.

Science.gov (United States)

Cawkwell, M J; Coe, J D; Yadav, S K; Liu, X-Y; Niklasson, A M N

2015-06-09

The extended Lagrangian Born-Oppenheimer molecular dynamics formalism [Niklasson, Phys. Rev. Lett., 2008, 100, 123004] has been applied to a tight-binding model under the constraint of local charge neutrality to yield microcanonical trajectories with both precise, long-term energy conservation and a reduced number of self-consistent field optimizations at each time step. The extended Lagrangian molecular dynamics formalism restores time reversal symmetry in the propagation of the electronic degrees of freedom, and it enables the efficient and accurate self-consistent optimization of the chemical potential and atomwise potential energy shifts in the on-site elements of the tight-binding Hamiltonian that are required when enforcing local charge neutrality. These capabilities are illustrated with microcanonical molecular dynamics simulations of a small metallic cluster using an sd-valent tight-binding model for titanium. The effects of weak dissipation on the propagation of the auxiliary degrees of freedom for the chemical potential and on-site Hamiltonian matrix elements that is used to counteract the accumulation of numerical noise during trajectories was also investigated.

Leakage detecting method and device for water tight vessel of wet-type container apparatus

International Nuclear Information System (INIS)

Tanaka, Yoshimi.

1995-01-01

The present invention provides a method of and a device for detecting leakage of a water tight vessel of a wet-type container apparatus for containing a reactor pressure vessel while immersing it water in a reactor container. Namely, in the wet-type container apparatus, the periphery of the pressure vessel is coated with a heat insulation material and the periphery of the heat insulation material is coated with a water tight vessel. The water tight vessel is immersed under water in the reactor container. As a method of detecting leakage of the wet-type container apparatus, gases mixed with helium are supplied into the water tight vessel at a pressure higher than the inner pressure of the reactor container at a lowest position of the reactor pressure vessel. A water level in the reactor container is determined so as to form a space at the top portion of the inside of the reactor container. The helium at the top portion is detected to monitor the leakage of the water tight vessel. With such procedures, even if the water tight vessel is ruptured at any position, helium mixed to the gases is released to water in the reactor container and rise up to the top space and detected by a helium leakage detection device. (I.S.)

Study seeks to boost Appalachian gas recovery

International Nuclear Information System (INIS)

Land, R.

1992-01-01

Ashland Exploration Inc. and the Gas Research Institute (GRI) are trying to find ways to increase gas recovery in the Appalachian basin. They are working together to investigate Mississippian Berea sandstone and Devonian shale in a program designed to achieve better understanding and improved performance of tight natural gas formations in the area. This paper reports that three wells on Ashland Exploration acreage in Pike County, Ky., are involved in the research program. Findings from the first two wells will be used to optimize evaluation and completion of the third well. The first two wells have been drilled. Drilling of the third well was under way at last report. Ashland Exploration has been involved with GRI's Devonian shale research since 1988. GRI's initial focus was on well stimulation because Devonian shale wells it reviewed had much lower recoveries than could be expected, based on estimated gas in place. Research during the past few years was designed to improve the execution and quality control of well stimulation

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.

Spatial and Temporal Characteristics of Historical Oil and Gas Wells in Pennsylvania: Implications for New Shale Gas Resources.

Science.gov (United States)

Dilmore, Robert M; Sams, James I; Glosser, Deborah; Carter, Kristin M; Bain, Daniel J

2015-10-20

Recent large-scale development of oil and gas from low-permeability unconventional formations (e.g., shales, tight sands, and coal seams) has raised concern about potential environmental impacts. If left improperly sealed, legacy oil and gas wells colocated with that new development represent a potential pathway for unwanted migration of fluids (brine, drilling and stimulation fluids, oil, and gas). Uncertainty in the number, location, and abandonment state of legacy wells hinders environmental assessment of exploration and production activity. The objective of this study is to apply publicly available information on Pennsylvania oil and gas wells to better understand their potential to serve as pathways for unwanted fluid migration. This study presents a synthesis of historical reports and digital well records to provide insights into spatial and temporal trends in oil and gas development. Areas with a higher density of wells abandoned prior to the mid-20th century, when more modern well-sealing requirements took effect in Pennsylvania, and areas where conventional oil and gas production penetrated to or through intervals that may be affected by new Marcellus shale development are identified. This information may help to address questions of environmental risk related to new extraction activities.

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.

Identification of MarvelD3 as a tight junction-associated transmembrane protein of the occludin family

Directory of Open Access Journals (Sweden)

Balda Maria S

2009-12-01

Full Text Available Abstract Background Tight junctions are an intercellular adhesion complex of epithelial and endothelial cells, and form a paracellular barrier that restricts the diffusion of solutes on the basis of size and charge. Tight junctions are formed by multiprotein complexes containing cytosolic and transmembrane proteins. How these components work together to form functional tight junctions is still not well understood and will require a complete understanding of the molecular composition of the junction. Results Here we identify a new transmembrane component of tight junctions: MarvelD3, a four-span transmembrane protein. Its predicted transmembrane helices form a Marvel (MAL and related proteins for vesicle traffic and membrane link domain, a structural motif originally discovered in proteins involved in membrane apposition and fusion events, such as the tight junction proteins occludin and tricellulin. In mammals, MarvelD3 is expressed as two alternatively spliced isoforms. Both isoforms exhibit a broad tissue distribution and are expressed by different types of epithelial as well as endothelial cells. MarvelD3 co-localises with occludin at tight junctions in intestinal and corneal epithelial cells. RNA interference experiments in Caco-2 cells indicate that normal MarvelD3 expression is not required for the formation of functional tight junctions but depletion results in monolayers with increased transepithelial electrical resistance. Conclusions Our data indicate that MarvelD3 is a third member of the tight junction-associated occludin family of transmembrane proteins. Similar to occludin, normal expression of MarvelD3 is not essential for the formation of functional tight junctions. However, MarvelD3 functions as a determinant of epithelial paracellular permeability properties.

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.

Reconstructing temperatures in the Maritime Alps, Italy, since the Last Glacial Maximum using cosmogenic noble gas paleothermometry

Science.gov (United States)

Tremblay, Marissa; Spagnolo, Matteo; Ribolini, Adriano; Shuster, David

2016-04-01

The Gesso Valley, located in the southwestern-most, Maritime portion of the European Alps, contains an exceptionally well-preserved record of glacial advances during the late Pleistocene and Holocene. Detailed geomorphic mapping, geochronology of glacial deposits, and glacier reconstructions indicate that glaciers in this Mediterranean region responded to millennial scale climate variability differently than glaciers in the interior of the European Alps. This suggests that the Mediterranean Sea somehow modulated the climate of this region. However, since glaciers respond to changes in temperature and precipitation, both variables were potentially influenced by proximity to the Sea. To disentangle the competing effects of temperature and precipitation changes on glacier size, we are constraining past temperature variations in the Gesso Valley since the Last Glacial Maximum (LGM) using cosmogenic noble gas paleothermometry. The cosmogenic noble gases 3He and 21Ne experience diffusive loss from common minerals like quartz and feldspars at Earth surface temperatures. Cosmogenic noble gas paleothermometry utilizes this open-system behavior to quantitatively constrain thermal histories of rocks during exposure to cosmic ray particles at the Earth's surface. We will present measurements of cosmogenic 3He in quartz sampled from moraines in the Gesso Valley with LGM, Bühl stadial, and Younger Dryas ages. With these 3He measurements and experimental data quantifying the diffusion kinetics of 3He in quartz, we will provide a preliminary temperature reconstruction for the Gesso Valley since the LGM. Future work on samples from younger moraines in the valley system will be used to fill in details of the more recent temperature history.

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.

Tightness of the thermal envelope of office and educational buildings; Klimaskaermens taethed i kontor- og undervisningsbygninger

Energy Technology Data Exchange (ETDEWEB)

Bergsoee, N.C. (SBi, Aalborg (Denmark)); Radisch, N.H.; Nickel, J.; Treldal, J. (Ramboell Danmark A/S, Koebenhavn (Denmark)); Bundesen, E.W.; Nielsen, Carsten (DanEjendomme, Hellerup (Denmark))

2011-07-01

In 2006 tightening of the energy regulations in the Danish Building Regulations were introduced including requirements regarding the tightness of the building envelope. The requirements are, with minor changes, continued in the current Building Regulations, BR10. During the past few years experience has been gained regarding both the actual execution of air tightness measurements and solutions that will lead to more air tight building envelopes. Experiences, however, are primarily related to single family houses. The report presents results of measurements in large buildings and discusses reasons for lack of knowledge and experience on the tightness of the building envelope in large buildings. Apparently, there is a need for dissemination of knowledge on the importance of a tight building envelope both in terms of energy consumption and indoor climate and in terms of the difficulties and costs associated with repairing leaks in a completed envelope. Air tightness must be brought into focus at an early stage in the planning process, and during the construction phase air tightness measurements should be performed, e.g. on facade sections or in parts of the building. The project team has attended a number of measurements in large buildings and further gained access to results of a large number of measurements. In summary, the results show that it is possible to achieve the required tightness, and in most buildings the results are better than the requirement of a maximum of 1.5 l/s per m{sub 2}. (Author)

Expression of Tight Junction Protein Claudin-1 in Human Crescentic Glomerulonephritis

Directory of Open Access Journals (Sweden)

Ryo Koda

2014-01-01

Full Text Available The origin of crescent forming cells in human glomerulonephritis (GN remains unknown. Some animal studies demonstrated that parietal epithelial cells of Bowman’s capsule (PECs were the main component of proliferating cells and PEC-specific tight junction protein claudin-1 was expressed in crescentic lesions. We investigated the expression of claudin-1 in human GN. Immunohistochemistry for claudin-1 was performed on 17 kidney biopsy samples with crescent formation. Colocalization of claudin-1 with intracellular tight junction protein ZO-1 was also evaluated by immunofluorescence double staining. Claudin-1 is expressed mainly at the cell to cell contact site of proliferating cells in cellular crescentic lesions in patients with these forms of human GN. Small numbers of crescent forming cells showed extrajunctional localization of claudin-1. Colocalization of claudin-1 with ZO-1 was found at cell to cell contact sites of adjacent proliferating cells. In control samples, staining of claudin-1 was positive in PECs, but not in podocytes. Our findings suggest that claudin-1 contributes to crescent formation as a component of the tight junction protein complex that includes ZO-1. Co-localization of claudin-1 with ZO-1 implies the formation of functional tight junction complexes in crescentic lesions to prevent the interstitial damage caused by penetration of filtered molecules from Bowman’s space.

Absolute tightness: the chemists hesitate to invest

International Nuclear Information System (INIS)

Anon.

1996-01-01

The safety requirements of industries as nuclear plants and the strengthening of regulations in the field of environment (more particularly those related to volatile organic compounds) have lead the manufacturers to build absolute tightness pumps. But these equipments do not answer all the problems and represent a high investment cost. In consequence, the chemists hesitate to invest. (O.L.)

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

Mixed Finite Element Simulation with Stability Analysis for Gas Transport in Low-Permeability Reservoirs

Directory of Open Access Journals (Sweden)

Mohamed F. El-Amin

2018-01-01

Full Text Available Natural gas exists in considerable quantities in tight reservoirs. Tight formations are rocks with very tiny or poorly connected pors that make flow through them very difficult, i.e., the permeability is very low. The mixed finite element method (MFEM, which is locally conservative, is suitable to simulate the flow in porous media. This paper is devoted to developing a mixed finite element (MFE technique to simulate the gas transport in low permeability reservoirs. The mathematical model, which describes gas transport in low permeability formations, contains slippage effect, as well as adsorption and diffusion mechanisms. The apparent permeability is employed to represent the slippage effect in low-permeability formations. The gas adsorption on the pore surface has been described by Langmuir isotherm model, while the Peng-Robinson equation of state is used in the thermodynamic calculations. Important compatibility conditions must hold to guarantee the stability of the mixed method by adding additional constraints to the numerical discretization. The stability conditions of the MFE scheme has been provided. A theorem and three lemmas on the stability analysis of the mixed finite element method (MFEM have been established and proven. A semi-implicit scheme is developed to solve the governing equations. Numerical experiments are carried out under various values of the physical parameters.

Critical heat flux experiments in tight lattice core

Energy Technology Data Exchange (ETDEWEB)

Kureta, Masatoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2002-12-01

Fuel rods of the Reduced-Moderation Water Reactor (RMWR) are so designed to be in tight lattices as to reduce moderation and achieve higher conversion ratio. As for the BWR type reactor coolant flow rate is reduced small compared with the existing BWR, so average void fraction comes to be langer. In order to evaluate thermo hydraulic characteristics of designed cores, critical heat flux experiments in tight lattice core have been conducted using simulated high pressure coolant loops for both the PWR and BWR seven fuel rod bundles. Experimental data on critical heat flux for full bundles have been accumulated and applied to assess the critical power of designed cores using existing codes. Evaluated results are conservative enough to satisfy the limiting condition. Further experiments on axial power distribution effects and 37 fuel rod bundle tests will be performed to validate thermohydraulic characteristics of designed cores. (T. Tanaka)

Critical heat flux experiments in tight lattice core

International Nuclear Information System (INIS)

Kureta, Masatoshi

2002-01-01

Fuel rods of the Reduced-Moderation Water Reactor (RMWR) are so designed to be in tight lattices as to reduce moderation and achieve higher conversion ratio. As for the BWR type reactor coolant flow rate is reduced small compared with the existing BWR, so average void fraction comes to be langer. In order to evaluate thermo hydraulic characteristics of designed cores, critical heat flux experiments in tight lattice core have been conducted using simulated high pressure coolant loops for both the PWR and BWR seven fuel rod bundles. Experimental data on critical heat flux for full bundles have been accumulated and applied to assess the critical power of designed cores using existing codes. Evaluated results are conservative enough to satisfy the limiting condition. Further experiments on axial power distribution effects and 37 fuel rod bundle tests will be performed to validate thermohydraulic characteristics of designed cores. (T. Tanaka)

ARTHROSCOPIC TREATMENT OF ACROMIOCLAVICULAR JOINT DISLOCATION BY TIGHT ROPE TECHNIQUE (ARTHREX®)

Science.gov (United States)

GÓmez Vieira, Luis Alfredo; Visco, Adalberto; Daneu Fernandes, Luis Filipe; GÓmez Cordero, Nicolas Gerardo

2015-01-01

Presenting the arthroscopic treatment by Tight Rope - Arthrex® system for acute acromioclavicular dislocation and to evaluate results obtained with this procedure. Methods: Between August 2006 and May 2007, 10 shoulders of 10 patients with acute acromioclavicular dislocation were submitted to arthroscopic repair using the Tight Rope - Arthrex® system. Minimum follow-up was 12 months, with a mean of 15 months. Age ranged from 26 to 42, mean 34 years. All patients were male. Radiology evaluation was made by trauma series x-ray. The patients were assisted in the first month weekly and after three months after the procedure. Clinical evaluation was based on the University of California at Los Angeles (UCLA) criteria. Results: All patients were satisfied after the arthroscopic procedure and the mean UCLA score was 32,5. Conclusion: The arthroscopic treatment by Tight Rope – Arthrex® system for acute acromioclavicular dislocation showed to be an efficient technique. PMID:26998453

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....

Natural gas market a dream come true

International Nuclear Information System (INIS)

Anon.

2000-01-01

Predictions by the U.S. Energy Information Administration to the effect that the unprecedented high gas prices of recent months are here to stay are discussed. The key symptom of the tightening market are the reduced level of storage in both Canada and the United States. In late May gas in U.S. storage facilities stood at 1.2 trillion cubic feet or 25 per cent less than the same time last year, and Canada's storage facilities were only 34 per cent full compared to 45 per cent a year earlier, a strong suggestion that the markets are extremely tight. The combination of limited supply, increasing demand and expanding pipeline connections are considered to be a winning combination to ensure that gas prices will remain high for the foreseeable future. The most significant growth in demand for natural gas is for use in electric power generation. To illustrate the increased penetration of natural gas into the field of power generation, it is noted that 98 per cent of the 243 electricity generating plants announced for construction in the next five years are designed to be fired by natural gas

Loosen up? Cultural tightness and national entrepreneurial activity

NARCIS (Netherlands)

Harms, Rainer; Groen, Arend J.

The level of entrepreneurship between countries differs consistently. A source of this variance lies in national culture differences. Recently, the cultural dimension “tightness” has been introduced in the literature. Tightness refers to the degree to which a nation has strong norms and a low

Trapping of Rydberg atoms in tight magnetic microtraps

NARCIS (Netherlands)

Boetes, A.Q.G.; Skannrup, R.V.; Naber, J.; Kokkelmans, S.J.J.M.F.; Spreeuw, R.J.C.

2018-01-01

We explore the possibility to trap Rydberg atoms in tightly confining magnetic microtraps. The trapping frequencies for Rydberg atoms are expected to be influenced strongly by magnetic-field gradients. We show that there are regimes where Rydberg atoms can be trapped. Moreover, we show that

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.

Hibernation and gas exchange.

Science.gov (United States)

Milsom, William K; Jackson, Donald C

2011-01-01

Hibernation in endotherms and ectotherms is characterized by an energy-conserving metabolic depression due to low body temperatures and poorly understood temperature-independent mechanisms. Rates of gas exchange are correspondly reduced. In hibernating mammals, ventilation falls even more than metabolic rate leading to a relative respiratory acidosis that may contribute to metabolic depression. Breathing in some mammals becomes episodic and in some small mammals significant apneic gas exchange may occur by passive diffusion via airways or skin. In ectothermic vertebrates, extrapulmonary gas exchange predominates and in reptiles and amphibians hibernating underwater accounts for all gas exchange. In aerated water diffusive exchange permits amphibians and many species of turtles to remain fully aerobic, but hypoxic conditions can challenge many of these animals. Oxygen uptake into blood in both endotherms and ectotherms is enhanced by increased affinity of hemoglobin for O₂ at low temperature. Regulation of gas exchange in hibernating mammals is predominately linked to CO₂/pH, and in episodic breathers, control is principally directed at the duration of the apneic period. Control in submerged hibernating ectotherms is poorly understood, although skin-diffusing capacity may increase under hypoxic conditions. In aerated water blood pH of frogs and turtles either adheres to alphastat regulation (pH ∼8.0) or may even exhibit respiratory alkalosis. Arousal in hibernating mammals leads to restoration of euthermic temperature, metabolic rate, and gas exchange and occurs periodically even as ambient temperatures remain low, whereas body temperature, metabolic rate, and gas exchange of hibernating ectotherms are tightly linked to ambient temperature. © 2011 American Physiological Society.

Vale do Aco pipeline: pipeline natural gas implementation in ArcelorMittal Monlevade steel work; Gasoduto Vale do Aco: implantacao do gas natural via gasoduto na ArcelorMittal Monlevade

Energy Technology Data Exchange (ETDEWEB)

Goncalves, Eduardo Sergio da Silva; Arantes, Luiz Flavio Mourao; Ribeiro, Vicente Aleixo Pinheiro [ArcelorMittal Monlevade, Joao Monlevade, MG (Brazil)

2011-12-21

Since September 2010, ArcelorMittal Monlevade has gained flexibility and an important opportunity to reduce the cost of its energy mix due to the arrival of the Natural Gas (NG) via Steel Valley Pipeline. The proposal of the project included the substitution of the Liquefied Petroleum Gas (LPG), Fuel Oil and Compressed Natural Gas for natural gas via pipeline. To support the investment decision, in addition to domestic economic and technical aspects, the macro economic environment concerning the NG was also taken into account. This paper shows the analysis for adjustment of internal equipment, the structure of the contract, the conceptual project of the gas distribution built inside the main events, the gains achieved, the alternatives for the acquisition of NG and operational flexibility of ArcelorMittal Monlevade in case of interruption of supply of natural gas. (author)

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

Urban air quality of kathmandu valley "Kingdom of Nepal"

Science.gov (United States)

Sharma, C. K.

The oval shaped tectonic basin of Kathmandu valley, occupying about 656 sq.km is situated in the middle sector of Himalayan range. There are three districts in the valley, i.e. Kathmandu, Lalitpur and Bhaktapur. Out of the three, the most populated is Kathmandu city (the capital of Kingdom of Nepal) which has a population of 668,00 in an area of approximately 50 km 2. The energy consumption of the city population is about 1/3 of the total import to Nepal of gasoline, diesel, kerosene, furnace oil and cooking gas. This has resulted heavy pollution of air in the city leading to bronchitis, and throat and chest diseases. Vehicles have increased several fold in recent months and there are 100,000 in number on the road and they have 900 km of road, out of which only 25% is metalled. Most of the two and three wheelers are polluting the air by emission of gases as well as dust particulate. SO 2 has been found to go as high as 202 μg cm -3 and NO 2 to 126 μg cm -3 particularly in winter months when a thick layer of fog covers the valley up to 10 am in the morning. All the gases are mixed within the limited air below the fog and the ground. This creates the problem. Furthermore, municipal waste of 500 m 3 a day and also liquid waste dumped directly into the Bagmati river at the rate of 500,000 ℓ d -1 makes the city ugly and filthy. Unless pollution of air, water and lard are controlled in time, Nepal will lose much of its foreign exchange earnings from the tourist industry. It is found that tourist arrivals have considerably reduced in recent years and most of hotels occupancy is 50-60% in peak time. Nepal is trying to introduce a legal framework for pollution control but it will take time to become effective.

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

Numerical simulation of flow behavior in tight lattice rod bundle

International Nuclear Information System (INIS)

Yu Yiqi; Yang Yanhua; Gu Hanyang; Cheng Xu; Song Xiaoming; Wang Xiaojun

2009-01-01

The Numerical investigation is performed on the air turbulent flow in triangular rod bundle array. Based on the experimental data, the eddy viscosity turbulent model and the Reynold stress turbulent model are evaluated to simulate the flow behavior in the tight lattice. The results show that SSG Reynolds Stress Model has shown superior predictive performance than other Reynolds-stress models, which indicates that the simulation of the anisotropy of the turbulence is significant in the tight lattice. The result with different Reynolds number and geometry shows that the magnitude of the secondary flow is almost independent of the Reynolds number, but it increases with the decrease of the P/D. (authors)

Ultra-Tightly Coupled GNSS/INS for small UAVs

DEFF Research Database (Denmark)

Olesen, Daniel; Jakobsen, Jakob; Knudsen, Per

2017-01-01

This paper describes an ultra-tight integration of a Global Navigation Satellite System ( GNSS) receiver and an Inertial Navigation System ( INS) for small Unmanned Aerial Vehicles ( UAVs). The system is based on a low-cost and low-weight GNSS Intermediate Frequency ( IF) sampler which has been...

The Clean Coal Technology Program 100 MWe demonstration of gas suspension absorption for flue gas desulfurization

Energy Technology Data Exchange (ETDEWEB)

Hsu, F.E.; Hedenhag, J.G. [AirPol Inc., Teterboro, NJ (United States); Marchant, S.K.; Pukanic, G.W. [Dept. of Energy, Pittsburgh, PA (United States). Pittsburgh Energy Technology Center; Norwood, V.M.; Burnett, T.A. [Tennessee Valley Authority, Chattanooga, TN (United States)

1997-12-31

AirPol Inc., with the cooperation of the Tennessee Valley Authority (TVA) under a Cooperative Agreement with the United States Department of Energy, installed and tested a 10 MWe Gas Suspension Absorption (GSA) Demonstration system at TVA`s Shawnee Fossil Plant near Paducah, Kentucky. This low-cost retrofit project demonstrated that the GSA system can remove more than 90% of the sulfur dioxide from high-sulfur coal-fired flue gas, while achieving a relatively high utilization of reagent lime. This paper presents a detailed technical description of the Clean Coal Technology demonstration project. Test results and data analysis from the preliminary testing, factorial tests, air toxics texts, 28-day continuous demonstration run of GSA/electrostatic precipitator (ESP), and 14-day continuous demonstration run of GSA/pulse jet baghouse (PJBH) are also discussed within this paper.

Outcome of tight versus standard glycemic control in coronary artery bypass patients

International Nuclear Information System (INIS)

Subhani, H.

2012-01-01

Objectives: To compare the outcome of tight versus standard glycemic control and its impact on post operative morbidity and short term mortality in patients undergoing Coronary Artery Bypass Grafting (CA-BG). Patients and Methods: A prospective surveillance of 124 patients undergoing isolated CABG surgery (on pump) was included in the study, 62 patients in each group were randomly assigned to tight and standard glucose control group. The main exposure was insulin in respect to level of blood glucose and the primary outcome measures were Sternotomy wound infection, Leg wound infection and new Myocardial Infarction. Surgical Site infection was assessed on a daily basis during the patient's stay in the Department of Cardio-thoracic Surgery, Sheikh Zayed Hospital, Lahore or within 30 days of operation prompting the patient to return to the hospital. Chi-square test or test was used to identify the significance of various short term morbidities and mortality. Results: In this study, 12 patients in the standard group and 4 patients in the tightly controlled group developed Sternal wound infection (p value 0.046). Similarly, 9 versus 2 patients in the standard and tight group respectively developed Leg wound infection (p-value 0.035). Test of proportion was applied and it was found that there was significant difference in the pro-portion of infection in the two groups (p value 0.05). However, there were no significant differences in other morbidities and the short term mortality. Conclusion: Study confirmed that tight glucose con-trol post operatively in CABG patient's results in reduced sternal and leg wound infection rates; however, there was no effect on other morbidities and short term mortality. (author)

Mapping deep aquifer salinity trends in the southern San Joaquin Valley using borehole geophysical data constrained by chemical analyses

Science.gov (United States)

Gillespie, J.; Shimabukuro, D.; Stephens, M.; Chang, W. H.; Ball, L. B.; Everett, R.; Metzger, L.; Landon, M. K.

2016-12-01

The California State Water Resources Control Board and the California Division of Oil, Gas and Geothermal Resources are collaborating with the U.S. Geological Survey to map groundwater resources near oil fields and to assess potential interactions between oil and gas development and groundwater resources. Groundwater resources having salinity less than 10,000 mg/L total dissolved solids may be classified as Underground Sources of Drinking Water (USDW) and subject to protection under the federal Safe Drinking Water Act. In this study, we use information from oil well borehole geophysical logs, oilfield produced water and groundwater chemistry data, and three-dimensional geologic surfaces to map the spatial distribution of salinity in aquifers near oil fields. Salinity in the southern San Joaquin Valley is controlled primarily by depth and location. The base of protected waters occurs at very shallow depths, often 1,500 meters, in the eastern part of the San Joaquin Valley where higher runoff from the western slopes of the Sierra Nevada provide relatively abundant aquifer recharge. Stratigraphy acts as a secondary control on salinity within these broader areas. Formations deposited in non-marine environments are generally fresher than marine deposits. Layers isolated vertically between confining beds and cut off from recharge sources may be more saline than underlying aquifers that outcrop in upland areas on the edge of the valley with more direct connection to regional recharge areas. The role of faulting is more ambiguous. In some areas, abrupt changes in salinity may be fault controlled but, more commonly, the faults serve as traps separating oil-bearing strata that are exempt from USDW regulations, from water-bearing strata that are not exempt.

Pressure drop characteristics in tight-lattice bundles for reduced-moderation water reactors

International Nuclear Information System (INIS)

Tamai, Hidesada; Kureta, Masatoshi; Yoshida, Hiroyuki; Akimoto, Hajime

2004-01-01

The reduced-moderation water reactor (RMWR) consists of several distinctive structures; a triangular tight-lattice configuration and a double-flat core. In order to design the RMWR core from the point of view of thermal-hydraulics, an evaluation method on pressure drop characteristics in the rod bundles at the tight-lattice configuration is required. In this study, calculated results by the Martinelli-Nelson's and Hancox's correlations were compared with experimental results in 4 x 5 rod bundles and seven-rod bundles. Consequently, the friction loss in two-phase flows becomes smaller at the tight-lattice configuration with the hydraulic diameter less than about 3 mm. This reason is due to the difference of the configuration between the multi-rod bundle and the circular tube and due to the effect of the small hydraulic diameter on the two-phase multiplier. (author)

Phase II, Title I engineering assessment of inactive uranium mill tailings, Monument Valley site, Monument Valley, Arizona

International Nuclear Information System (INIS)

1977-01-01

An engineering assessment was made of the problems resulting from the existence of radioactive uranium mill tailings at the Monument Valley millsite in Arizona. The Phase II, Title I services include the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and other radium-contaminated materials, the evaluation of resulting radiation exposures of individuals residing nearby, the investigation of site hydrology and meteorology and the evaluation and costing of alternative corrective actions. Radon gas release from the tailings on the site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The sparse population and relatively low radiation levels yield minimal immediate environmental impact; hence, the two alternative actions presented are directed towards restricting access to the site and returning the windblown tailings to the pile and stabilizing the pile. Both options include remedial action costs for offsite locations where tailings have been placed. Cost estimates for the two options are $585,000 and $1,165,000

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.

Laser spectroscopy of gas confined in nanoporous materials

OpenAIRE

Svensson, Tomas; Shen, Zhijian

2010-01-01

We show that high-resolution laser spectroscopy can probe surface interactions of gas confined in nanocavities of porous materials. We report on strong line broadening and unfamiliar line shapes due to tight confinement, as well as signal enhancement due to multiple photon scattering. This new domain of laser spectroscopy constitute a challenge for the theory of collisions and spectroscopic line shapes, and open for new ways of analyzing porous materials and processes taking place therein.

Quantum tight-binding chains with dissipative coupling

International Nuclear Information System (INIS)

Mogilevtsev, D; Slepyan, G Ya; Garusov, E; Kilin, S Ya; Korolkova, N

2015-01-01

We present a one-dimensional tight-binding chain of two-level systems coupled only through common dissipative Markovian reservoirs. This quantum chain can demonstrate anomalous thermodynamic behavior contradicting Fourier law. Population dynamics of individual systems of the chain is polynomial with the order determined by the initial state of the chain. The chain can simulate classically hard problems, such as multi-dimensional random walks. (paper)

Experimental evaluation on the damages of different drilling modes to tight sandstone reservoirs

Directory of Open Access Journals (Sweden)

Gao Li

2017-07-01

Full Text Available The damages of different drilling modes to reservoirs are different in types and degrees. In this paper, the geologic characteristics and types of such damages were analyzed. Then, based on the relationship between reservoir pressure and bottom hole flowing pressure corresponding to different drilling modes, the experimental procedures on reservoir damages in three drilling modes (e.g. gas drilling, liquid-based underbalanced drilling and overbalanced drilling were designed. Finally, damage simulation experiments were conducted on the tight sandstone reservoir cores of the Jurassic Ahe Fm in the Tarim Basin and Triassic Xujiahe Fm in the central Sichuan Basin. It is shown that the underbalanced drilling is beneficial to reservoir protection because of its less damage on reservoir permeability, but it is, to some extent, sensitive to the stress and the empirical formula of stress sensitivity coefficient is obtained; and that the overbalanced drilling has more reservoir damages due to the invasion of solid and liquid phases. After the water saturation of cores rises to the irreducible water saturation, the decline of gas logging permeability speeds up and the damage degree of water lock increases. It is concluded that the laboratory experiment results of reservoir damage are accordant with the reservoir damage characteristics in actual drilling conditions. Therefore, this method reflects accurately the reservoir damage characteristics and can be used as a new experimental evaluation method on reservoir damage in different drilling modes.

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.

Canadian gas resource

International Nuclear Information System (INIS)

Anon.

1989-01-01

Canadian exports of gas to the United States are a critical component of EMF-9 (North American Gas Supplies). However, it has been noted that there are differences between US expectations for imports and Canadian forecasts of export supply capacity. Recent studies by the National Petroleum Council (NPC) and the US Department of Energy (DOE) indicate that 1.8 to 2.4 Tcf of imports may be required in the mid to late 1990's; A recent study by Canada's National Energy Board (NEB) indicates that the conventional resource base may not be able to provide continued gas exports to the US after the mid 1990's and that frontier sources would need to be developed to meet US expectations. The discrepancies between US expectations and Canadian estimates of capacity are of great concern to US policymakers because they call into question the availability of secure supplies of natural gas and suggest that the cost of imports (if available) will be high. By implication, if shortages are to be averted, massive investment may be required to bring these higher cost sources to market. Since the long-term supply picture will be determined by the underlying resource base, EMF-9 participants have been asked to provide estimates of critical components of the Canadian resource base. This paper provides a summary of ICF-Lewin's recent investigation of both the Conventional and Tight Gas resource in Canada's Western Sedimentary Basin, which includes both quantitative estimates and a brief sketch of the analysis methodology

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.

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.

What place for shale gas in fighting climate change?

International Nuclear Information System (INIS)

2010-09-01

Along with petroleum and coal, natural gas is the primary cause of global warming. Equiterre believes that the energy sector must be completely decarbonised by 2050 if catastrophic consequences caused by this warming are to be avoided. The Utica shale formation in the Saint Lawrence Valley has been the object of much prospecting activity. The aim of the present study is therefore to determine if the development of shale gas can play a transitional role in the move towards a decarbonised energy system. To do this, Equiterre considers that gas should be substituted for more polluting fuels as quickly as possible and that thereafter it should be rapidly replaced by carbon-free fuels. Equiterre also considers, however, that the establishment of a shale gas industry in Quebec would only increase the overall volume of greenhouse gas emissions. Equiterre concludes that the setting up of a shale gas industry in Quebec is a purely commercial proposition which, at the best, would contribute nothing to the struggle to combat climate change.

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.

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.

Efficient self-consistency for magnetic tight binding

Science.gov (United States)

Soin, Preetma; Horsfield, A. P.; Nguyen-Manh, D.

2011-06-01

Tight binding can be extended to magnetic systems by including an exchange interaction on an atomic site that favours net spin polarisation. We have used a published model, extended to include long-ranged Coulomb interactions, to study defects in iron. We have found that achieving self-consistency using conventional techniques was either unstable or very slow. By formulating the problem of achieving charge and spin self-consistency as a search for stationary points of a Harris-Foulkes functional, extended to include spin, we have derived a much more efficient scheme based on a Newton-Raphson procedure. We demonstrate the capabilities of our method by looking at vacancies and self-interstitials in iron. Self-consistency can indeed be achieved in a more efficient and stable manner, but care needs to be taken to manage this. The algorithm is implemented in the code PLATO. Program summaryProgram title:PLATO Catalogue identifier: AEFC_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFC_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 228 747 No. of bytes in distributed program, including test data, etc.: 1 880 369 Distribution format: tar.gz Programming language: C and PERL Computer: Apple Macintosh, PC, Unix machines Operating system: Unix, Linux, Mac OS X, Windows XP Has the code been vectorised or parallelised?: Yes. Up to 256 processors tested RAM: Up to 2 Gbytes per processor Classification: 7.3 External routines: LAPACK, BLAS and optionally ScaLAPACK, BLACS, PBLAS, FFTW Catalogue identifier of previous version: AEFC_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 2616 Does the new version supersede the previous version?: Yes Nature of problem: Achieving charge and spin self-consistency in magnetic tight binding can be very

Shallow gas accumulation in sediments of the Patos Lagoon, Southern Brazil

Energy Technology Data Exchange (ETDEWEB)

Weschenfelder, Jair; Corrrea, Iran C.S.; Pereira, Carla M.; Vasconcellos, Vinicius E.B. de [Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil). Inst. de Geociencias; Aliotta, Salvador [Instituto Argentino de Oceanografia Complejo CRIBABB, Bahia Blanca (Argentina)

2006-07-15

A high resolution seismic survey was conducted in the Patos Lagoon, southern Brazil, aboard of the research vessel LARUS of the Fundacao Universidade Federal do Rio Grande (FURG). Around 400 km of 3.5 k Hz seismic profiles were collected, which provided acoustic signals of good penetration depth and resolution. Seismic anomalies, including turbidity and pocket gas, revealed that gas-charged sediments are common in several areas of the lagoon. The gas accumulations in the Patos Lagoon are controlled by the spatial distribution of the sedimentary facies. Either in 'curtains' or in 'acoustic turbid zones', the main gas accumulations occur in areas with paleotopographic lows related to fluvial channels and valleys developed in the Rio Grande do Sul coastal plain during regressive/transgressive events of the Quaternary. (author)

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

Trapping a Knot into Tight Conformations by Intra-Chain Repulsions

Directory of Open Access Journals (Sweden)

Liang Dai

2017-02-01

Full Text Available Knots can occur in biopolymers such as DNA and peptides. In our previous study, we systematically investigated the effects of intra-chain interactions on knots and found that long-range repulsions can surprisingly tighten knots. Here, we use this knowledge to trap a knot into tight conformations in Langevin dynamics simulations. By trapping, we mean that the free energy landscape with respect to the knot size exhibits a potential well around a small knot size in the presence of long-range repulsions, and this potential can well lead to long-lived tight knots when its depth is comparable to or larger than thermal energy. We tune the strength of intra-chain repulsion such that a knot is weakly trapped. Driven by thermal fluctuations, the knot can escape from the trap and is then re-trapped. We find that the knot switches between tight and loose conformations—referred to as “knot breathing”. We use a Yukawa potential to model screened electrostatic interactions to explore the relevance of knot trapping and breathing in charged biopolymers. We determine the minimal screened length and the minimal strength of repulsion for knot trapping. We find that Coulomb-induced knot trapping is possible to occur in single-stranded DNA and peptides for normal ionic strengths.

Preconditioning Filter Bank Decomposition Using Structured Normalized Tight Frames

Directory of Open Access Journals (Sweden)

Martin Ehler

2015-01-01

Full Text Available We turn a given filter bank into a filtering scheme that provides perfect reconstruction, synthesis is the adjoint of the analysis part (so-called unitary filter banks, all filters have equal norm, and the essential features of the original filter bank are preserved. Unitary filter banks providing perfect reconstruction are induced by tight generalized frames, which enable signal decomposition using a set of linear operators. If, in addition, frame elements have equal norm, then the signal energy is spread through the various filter bank channels in some uniform fashion, which is often more suitable for further signal processing. We start with a given generalized frame whose elements allow for fast matrix vector multiplication, as, for instance, convolution operators, and compute a normalized tight frame, for which signal analysis and synthesis still preserve those fast algorithmic schemes.

Sutter Buttes-the lone volcano in California's Great Valley

Science.gov (United States)

Hausback, Brain P.; Muffler, L.J. Patrick; Clynne, Michael A.

2011-01-01

The volcanic spires of the Sutter Buttes tower 2,000 feet above the farms and fields of California's Great Valley, just 50 miles north-northwest of Sacramento and 11 miles northwest of Yuba City. The only volcano within the valley, the Buttes consist of a central core of volcanic domes surrounded by a large apron of fragmental volcanic debris. Eruptions at the Sutter Buttes occurred in early Pleistocene time, 1.6 to 1.4 million years ago. The Sutter Buttes are not part of the Cascade Range of volcanoes to the north, but instead are related to the volcanoes in the Coast Ranges to the west in the vicinity of Clear Lake, Napa Valley, and Sonoma Valley.

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.

An efficient magnetic tight-binding method for transition metals and alloys

DEFF Research Database (Denmark)

Barreteau, Cyrille; Spanjaard, Daniel; Desjonquères, Marie-Catherine

2016-01-01

that does not necessitate any further fitting is proposed to deal with systems made of several chemical elements. This model is extended to spin (and orbital) polarized materials by adding Stoner-like and spin–orbit interactions. Collinear and non-collinear magnetism as well as spin-spirals are considered......An efficient parameterized self-consistent tight-binding model for transition metals using s, p and d valence atomic orbitals as a basis set is presented. The parameters of our tight-binding model for pure elements are determined from a fit to bulk ab-initio calculations. A very simple procedure...

Tight junction-associated MARVEL proteins marveld3, tricellulin, and occludin have distinct but overlapping functions.

Science.gov (United States)

Raleigh, David R; Marchiando, Amanda M; Zhang, Yong; Shen, Le; Sasaki, Hiroyuki; Wang, Yingmin; Long, Manyuan; Turner, Jerrold R

2010-04-01

In vitro studies have demonstrated that occludin and tricellulin are important for tight junction barrier function, but in vivo data suggest that loss of these proteins can be overcome. The presence of a heretofore unknown, yet related, protein could explain these observations. Here, we report marvelD3, a novel tight junction protein that, like occludin and tricellulin, contains a conserved four-transmembrane MARVEL (MAL and related proteins for vesicle trafficking and membrane link) domain. Phylogenetic tree reconstruction; analysis of RNA and protein tissue distribution; immunofluorescent and electron microscopic examination of subcellular localization; characterization of intracellular trafficking, protein interactions, dynamic behavior, and siRNA knockdown effects; and description of remodeling after in vivo immune activation show that marvelD3, occludin, and tricellulin have distinct but overlapping functions at the tight junction. Although marvelD3 is able to partially compensate for occludin or tricellulin loss, it cannot fully restore function. We conclude that marvelD3, occludin, and tricellulin define the tight junction-associated MARVEL protein family. The data further suggest that these proteins are best considered as a group with both redundant and unique contributions to epithelial function and tight junction regulation.

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.

Design and operating features of the high-level waste vitrification system for the West Valley demonstration project

International Nuclear Information System (INIS)

Siemens, D.H.; Beary, M.M.; Barnes, S.M.; Berger, D.N.; Brouns, R.A.; Chapman, C.C.; Jones, R.M.; Peters, R.D.; Peterson, M.E.

1986-03-01

A liquid-fed joule-heated ceramic melter system is the reference process for immobilization of the high-level liquid waste in the US and several foreign countries. This system has been under development for over ten years at Pacific Northwest Laboratory and other national laboratories operated for the US Department of Energy. Pacific Northwest Laboratory contributed to this research through its Nuclear Waste Treatment Program and used applicable data to design and test melters and related systems using remote handling of simulated radioactive wastes. This report describes the equipment designed in support of the high-level waste vitrification program at West Valley, New York. Pacific Northwest Laboratory worked closely with West Valley Nuclear Services Company to design a liquid-fed ceramic melter, a liquid waste preparation and feed tank and pump, an off-gas treatment scrubber, and an enclosed turntable for positioning the waste canisters. Details of these designs are presented including the rationale for the design features and the alternatives considered

Four newly recorded species of Dryopteridaceae from Kashmir valley, India

Directory of Open Access Journals (Sweden)

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.

Wounds caused by tight contact with the barrel-cylinder gap of revolvers.

Science.gov (United States)

Rogers, D R

1984-06-01

A case is presented in which the recognition of a tight cylinder gap contact wound was crucial. Experiments were carried out to reproduce the wound which was noted on the hand of a robbery suspect. Tight contact with the cylinder gap of a revolver produces a characteristic, readily recognizable wound. It is characterized by an L-shaped pattern of powder residue. Along one axis a searing burn may occur which may be deep and which may lead to significant tissue destruction.

LIFAC Demonstration at Richmond Power and Light Whitewater Valley Unit No. 2 Volume II: Project Performance and Economics

Energy Technology Data Exchange (ETDEWEB)

None, None

1998-04-01

The C1ean Coal Technology (CCT) Program has been recognized in the National Energy Strategy as a major initiative whereby coal will be able to reach its full potential as a source of energy for the nation and the international marketplace. Attainment of this goal depends upon the development of highly efficient, environmentally sound, competitive coal utilization technologies responsive to diverse energy markets and varied consumer needs. The CCT Program is an effort jointly funded by government and industry whereby the most promising of the advanced coal-based technologies are being moved into the marketplace through demonstration. The CCT Program is being implemented through a total of five competitive solicitations. LIFAC North America, a joint venture partnership of ICF Kaiser Engineers, Inc., and Tampella Power Corporation, is currently demonstrating the LIFAC flue gas desulfurization technology developed by Tampella Power. This technology provides sulfur dioxide emission control for power plants, especially existing facilities with tight space limitations. Sulfur dioxide emissions are expected to be reduced by up to 85% by using limestone as a sorbent. The LIFAC technology is being demonstrated at Whitewater Valley Unit No. 2, a 60-MW coal-fired power plant owned and operated by Richmond Power and Light (RP&L) and located in Richmond, Indiana. The Whitewater plant consumes high-sulfur coals, with sulfur contents ranging from 2.0-2.9 $ZO. The project, co-funded by LIFAC North America and DOE, is being conducted with the participation of Richmond Power and Light, the State of Indiana, the Electric Power Research Institute (EPRI), and the Black Beauty Coal Company. The project has a total cost of $21.4 million and a duration of 48 months from the preliminary design phase through the testing program.

Studies of matrix diffusion in gas phase

International Nuclear Information System (INIS)

Hartikainen, K.; Timonen, J.; Vaeaetaeinen, K.; Pietarila, H.

1994-03-01

The diffusion of solutes from fractures into rock matrix is an important factor in the safety analysis of disposal of radioactive waste. Laboratory measurements are needed to complement field investigations for a reliable determination of the necessary transport parameters. Measurements of diffusion coefficients in tight rock samples are usually time consuming because the diffusion processes are slow. On the other hand it is well known that diffusion coefficients in the gas phase are roughly four orders of magnitude larger than those in the liquid phase. Therefore, for samples whose structures do not change much upon drying, it is possible to estimate the diffusion properties of the liquid phase when the properties of the gas phase are known. Advantages of the gas method are quick and easy measurements. In the measurements nitrogen was used as the carrier gas and helium as the tracer gas, and standard techniques have been used for helium detection. Techniques have been developed for both channel flow and through-diffusion measurements. The breakthrough curves have been measured in every experiment and all measurements have been modelled by using appropriate analytical models. As a result matrix porosities and effective diffusion coefficients in the gas phase have been determined. (12 refs., 21 figs., 6 tabs.)

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.

Management of Small Urethrocutaneous Fistula by Tight Ligation ...

African Journals Online (AJOL)

After identifying the fistulous opening, the fistula tract was circumferentially and meticulously dissected ,then the dissected tract was lifted up and the base was ligated tightly with 5/0 vicryl, the external epithelium of the dissected tract was fulgurated with the diathermy, then a second layer of local soft tissue was secured over ...

Tight Reference Frame–Independent Quantum Teleportation

Directory of Open Access Journals (Sweden)

Dominic Verdon

2017-01-01

Full Text Available We give a tight scheme for teleporting a quantum state between two parties whose reference frames are misaligned by an action of a finite symmetry group. Unlike previously proposed schemes, ours requires no additional tokens or data to be passed between the participants; the same amount of classical information is transferred as for ordinary quantum teleportation, and the Hilbert space of the entangled resource is of the same size. In the terminology of Peres and Scudo, our protocol relies on classical communication of unspeakable information.

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.

Alberta benefits : economic impacts of northern gas pipeline construction

International Nuclear Information System (INIS)

Rylska, N.L.; Graebeiel, J.E.; Mirus, R.K.; Janzen, S.S.; Frost, R.J.

2003-11-01

This paper describes the potential economic impact and benefits to Alberta from the proposed development of the Alaska Highway Pipeline (AHP) and the Mackenzie Valley Pipeline (MVP). It also includes a planning framework for business and industry in the province. Each proposed pipeline was evaluated separately. The paper includes a list of Alberta companies that stand to benefit from the construction of one or both pipelines. The main findings indicate that northern pipeline development will bring opportunities to Alberta business in design, construction and management. There will be a secondary impact on petrochemical industries and infrastructure. Both pipeline developments will increase employment and yield billions of dollars in gross domestic product. The existing oil and gas industry in Alberta will receive value-added opportunities in areas of specialized expertise such as natural gas and natural gas liquid storage, natural gas liquid processing, and gas to liquid technology projects. The industry will also benefit from power generation and cogeneration. The northern pipelines have the potential to improve the role of First Nations in economic development. Gas consumers in Alberta should benefit from a secure supply of gas and lower prices. refs., tabs., figs

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)

DNA sensor cGAS-mediated immune recognition

Directory of Open Access Journals (Sweden)

Pengyan Xia

2016-09-01

Full Text Available Abstract The host takes use of pattern recognition receptors (PRRs to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from bacteria or viruses are tightly supervised, providing a fundamental mechanism of host defense. Pathogenic DNAs are supposed to be detected by DNA sensors that induce the activation of NFκB or TBK1-IRF3 pathway. DNA sensor cGAS is widely expressed in innate immune cells and is a key sensor of invading DNAs in several cell types. cGAS binds to DNA, followed by a conformational change that allows the synthesis of cyclic guanosine monophosphate–adenosine monophosphate (cGAMP from adenosine triphosphate and guanosine triphosphate. cGAMP is a strong activator of STING that can activate IRF3 and subsequent type I interferon production. Here we describe recent progresses in DNA sensors especially cGAS in the innate immune responses against pathogenic DNAs.

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.

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)

Natural gas production verification tests

International Nuclear Information System (INIS)

1992-02-01

This Environmental Assessment (EA) has been prepared by the Department of Energy (DOE) in compliance with the requirements of the National Environmental Policy Act of 1969. The Department of Energy (DOE) proposes to fund, through a contract with Petroleum Consulting Services, Inc. of Canton, Ohio, the testing of the effectiveness of a non-water based hydraulic fracturing treatment to increase gas recovery from low-pressure, tight, fractured Devonian Shale formations. Although Devonian Shales are found in the Appalachian, Michigan, and Illinois Basins, testing will be done only in the dominant, historical five state area of established production. The objective of this proposed project is to assess the benefits of liquid carbon dioxide (CO 2 )/sand stimulations in the Devonian Shale. In addition, this project would evaluate the potential nondamaging (to the formation) properties of this unique fracturing treatment relative to the clogging or chocking of pores and fractures that act as gas flow paths to the wellbore in the target gas-producing zones of the formation. This liquid CO 2 /sand fracturing process is water-free and is expected to facilitate gas well cleanup, reduce the time required for post-stimulation cleanup, and result in improved production levels in a much shorter time than is currently experienced

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.

Two-Finger Tightness: What Is It? Measuring Torque and Reproducibility in a Simulated Model.

Science.gov (United States)

Acker, William B; Tai, Bruce L; Belmont, Barry; Shih, Albert J; Irwin, Todd A; Holmes, James R

2016-05-01

Residents in training are often directed to insert screws using "two-finger tightness" to impart adequate torque but minimize the chance of a screw stripping in bone. This study seeks to quantify and describe two-finger tightness and to assess the variability of its application by residents in training. Cortical bone was simulated using a polyurethane foam block (30-pcf density) that was prepared with predrilled holes for tightening 3.5 × 14-mm long cortical screws and mounted to a custom-built apparatus on a load cell to capture torque data. Thirty-three residents in training, ranging from the first through fifth years of residency, along with 8 staff members, were directed to tighten 6 screws to two-finger tightness in the test block, and peak torque values were recorded. The participants were blinded to their torque values. Stripping torque (2.73 ± 0.56 N·m) was determined from 36 trials and served as a threshold for failed screw placement. The average torques varied substantially with regard to absolute torque values, thus poorly defining two-finger tightness. Junior residents less consistently reproduced torque compared with other groups (0.29 and 0.32, respectively). These data quantify absolute values of two-finger tightness but demonstrate considerable variability in absolute torque values, percentage of stripping torque, and ability to consistently reproduce given torque levels. Increased years in training are weakly correlated with reproducibility, but experience does not seem to affect absolute torque levels. These results question the usefulness of two-finger tightness as a teaching tool and highlight the need for improvement in resident motor skill training and development within a teaching curriculum. Torque measuring devices may be a useful simulation tools for this purpose.

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.

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.

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.

INFLUENCE OF FABRIC TIGHTNESS ON SPIRALITY OF WEFTKNITTED PLAIN COTTON FABRIC

Directory of Open Access Journals (Sweden)

A.K.M. Mobarok Hossain

2011-01-01

Full Text Available Global demand for knitted garments is growing at a faster rate than that of woven items.Currently around 50% of clothing needs in the developed countries is met by knit goods. So ensuring the required quality in a knitted fabric is a vital issue for the manufacturer. One of the major problems encountered in knitted fabric is spirality. It affects particularly single jersey fabric and presents a serious problem during garment confection and use. So controlling spirality is a basic requirement for producing quality knitted fabric. Though there are several factors that contribute to knitted fabric spirality, yarn twist and relative tightness of the fabric are said tobe the most significant ones. In this work the basic single jersey fabric, i.e. plain jersey cotton fabrics were produced by a Hosiery knitting machine and spirality values were observed for different yarn T.P.I. and tightness factor at relaxed state. It was found that tightness factor has a direct influence on knitted fabric spirality with a high degree of correlation. The work thus gives an idea to deal this problem by controlling the knitting parameters.

Glutamylation of the DNA sensor cGAS regulates its binding and synthase activity in antiviral immunity.

Science.gov (United States)

Xia, Pengyan; Ye, Buqing; Wang, Shuo; Zhu, Xiaoxiao; Du, Ying; Xiong, Zhen; Tian, Yong; Fan, Zusen

2016-04-01

Cyclic GMP-AMP synthase (cGAS) senses cytosolic DNA during viral infection and catalyzes synthesis of the dinucleotide cGAMP, which activates the adaptor STING to initiate antiviral responses. Here we found that deficiency in the carboxypeptidase CCP5 or CCP6 led to susceptibility to DNA viruses. CCP5 and CCP6 were required for activation of the transcription factor IRF3 and interferons. Polyglutamylation of cGAS by the enzyme TTLL6 impeded its DNA-binding ability, whereas TTLL4-mediated monoglutamylation of cGAS blocked its synthase activity. Conversely, CCP6 removed the polyglutamylation of cGAS, whereas CCP5 hydrolyzed the monoglutamylation of cGAS, which together led to the activation of cGAS. Therefore, glutamylation and deglutamylation of cGAS tightly modulate immune responses to infection with DNA viruses.

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

Dielectric constant of graphene-on-polarized substrate: A tight ...

Indian Academy of Sciences (India)

2017-06-24

Jun 24, 2017 ... We report here a microscopic tight-binding theoretical study of the dynamic dielectric response of graphene-on-polarizable substrate with impurity. The Hamiltonian consists of first, second and third nearest neighbour electron hopping interactions besides doping and substrate-induced effects on graphene.

Intraoperative tight glucose control using hyperinsulinemic normoglycemia increases delirium after cardiac surgery.

Science.gov (United States)

Saager, Leif; Duncan, Andra E; Yared, Jean-Pierre; Hesler, Brian D; You, Jing; Deogaonkar, Anupa; Sessler, Daniel I; Kurz, Andrea

2015-06-01

Postoperative delirium is common in patients recovering from cardiac surgery. Tight glucose control has been shown to reduce mortality and morbidity. Therefore, the authors sought to determine the effect of tight intraoperative glucose control using a hyperinsulinemic-normoglycemic clamp approach on postoperative delirium in patients undergoing cardiac surgery. The authors enrolled 198 adult patients having cardiac surgery in this randomized, double-blind, single-center trial. Patients were randomly assigned to either tight intraoperative glucose control with a hyperinsulinemic-normoglycemic clamp (target blood glucose, 80 to 110 mg/dl) or standard therapy (conventional insulin administration with blood glucose target, battery. The authors considered patients to have experienced postoperative delirium when Confusion Assessment Method testing was positive at any assessment. A positive Confusion Assessment Method was defined by the presence of features 1 (acute onset and fluctuating course) and 2 (inattention) and either 3 (disorganized thinking) or 4 (altered consciousness). Patients randomized to tight glucose control were more likely to be diagnosed as being delirious than those assigned to routine glucose control (26 of 93 vs. 15 of 105; relative risk, 1.89; 95% CI, 1.06 to 3.37; P = 0.03), after adjusting for preoperative usage of calcium channel blocker and American Society of Anesthesiologist physical status. Delirium severity, among patients with delirium, was comparable with each glucose management strategy. Intraoperative hyperinsulinemic-normoglycemia augments the risk of delirium after cardiac surgery, but not its severity.

Experimental Air-Tightness Analysis in Mediterranean Buildings after Windows Retrofit

Directory of Open Access Journals (Sweden)

Francesca Romana d’Ambrosio Alfano

2016-09-01

Full Text Available Energy saving and Indoor Air Quality (IAQ in buildings are strongly affected by air leakages. Several studies reveal that the energy loss owing to leaky windows can account for up to 40% of the total building energy demand. Furthermore, at the design stage, the possible infiltration of outdoor air through windows is not taken into account when determining the nominal outdoor airflow rate of the ventilation system. This practice may result in an oversizing of the ventilation system and consequent energy waste. Thus, the air-tightness class of a wall assembly should be assessed for each window component considering the type of material, the presence of the seal, the type of closure, the sealing and the maintenance condition. In this paper, the authors present the experimental results of air-tightness measurements carried out using the fan pressurization method in three residential buildings located in the Mediterranean region before and after a window retrofit. Two different window retrofits were investigated: the application of rubber seals on window frames and the substitution of existing windows with new certified high performance windows. The effectiveness of such retrofits was estimated also in terms of energy saving. Test results demonstrated a high variability of the building air tightness after window retrofits, despite the fact that air tight–certified windows were used.

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

Permeability in Rotliegend gas sandstones to gas and brine as predicted from NMR, mercury injection and image analysis

DEFF Research Database (Denmark)

Rosenbrand, Esther; Fabricius, Ida Lykke; Fisher, Quentin

2015-01-01

Permeability characterisation of low permeability, clay-rich gas sandstones is part of production forecasting and reservoir management. The physically based Kozeny (1927) equation linking permeability with porosity and pore size is derived for a porous medium with a homogeneous pore size, whereas...... the pore sizes in tight sandstones can range from nm to μm. Nuclear magnetic resonance (NMR) transverse relaxation was used to estimate a pore size distribution for 63 samples of Rotliegend sandstone. The surface relaxation parameter required to relate NMR to pore size is estimated by combination of NMR...

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.

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.

Documentation of the Oil and Gas Supply Module (OGSM)

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

The purpose of this report is to define the objectives of the Oil and Gas Supply Model (OGSM), to describe the model`s basic approach, and to provide detail on how the model works. This report is intended as a reference document for model analysts, users, and the public. Projected production estimates of US crude oil and natural gas are based on supply functions generated endogenously within National Energy Modeling System (NEMS) by the OGSM. OGSM encompasses domestic crude oil and natural gas supply by both conventional and nonconventional recovery techniques. Nonconventional recovery includes enhanced oil recovery (EOR), and unconventional gas recovery (UGR) from tight gas formations, Devonian/Antrim shale and coalbeds. Crude oil and natural gas projections are further disaggregated by geographic region. OGSM projects US domestic oil and gas supply for six Lower 48 onshore regions, three offshore regions, and Alaska. The general methodology relies on forecasted profitability to determine exploratory and developmental drilling levels for each region and fuel type. These projected drilling levels translate into reserve additions, as well as a modification of the production capacity for each region. OGSM also represents foreign trade in natural gas, imports and exports by entry region. Foreign gas trade may occur via either pipeline (Canada or Mexico), or via transport ships as liquefied natural gas (LNG). These import supply functions are critical elements of any market modeling effort.

Intricate but tight coupling of spiracular activity and abdominal ventilation during locust discontinuous gas exchange cycles.

Science.gov (United States)

Talal, Stav; Gefen, Eran; Ayali, Amir

2018-03-15

Discontinuous gas exchange (DGE) is the best studied among insect gas exchange patterns. DGE cycles comprise three phases, which are defined by their spiracular state: closed, flutter and open. However, spiracle status has rarely been monitored directly; rather, it is often assumed based on CO 2 emission traces. In this study, we directly recorded electromyogram (EMG) signals from the closer muscle of the second thoracic spiracle and from abdominal ventilation muscles in a fully intact locust during DGE. Muscular activity was monitored simultaneously with CO 2 emission, under normoxia and under various experimental oxic conditions. Our findings indicate that locust DGE does not correspond well with the commonly described three-phase cycle. We describe unique DGE-related ventilation motor patterns, coupled to spiracular activity. During the open phase, when CO 2 emission rate is highest, the thoracic spiracles do not remain open; rather, they open and close rapidly. This fast spiracle activity coincides with in-phase abdominal ventilation, while alternating with the abdominal spiracle and thus facilitating a unidirectional air flow along the main trachea. A change in the frequency of rhythmic ventilation during the open phase suggests modulation by intra-tracheal CO 2 levels. A second, slow ventilatory movement pattern probably serves to facilitate gas diffusion during spiracle closure. Two flutter-like patterns are described in association with the different types of ventilatory activity. We offer a modified mechanistic model for DGE in actively ventilating insects, incorporating ventilatory behavior and changes in spiracle state. © 2018. Published by The Company of Biologists Ltd.

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.

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.

A tightly coupled scheme for neutronics and thermal–hydraulics using open-source software

International Nuclear Information System (INIS)

Wu, Hsingtzu; Rizwan-uddin

2016-01-01

Highlights: • A novel tight coupling scheme called “the Integrated Tight Coupling (ITC) method” is proposed. • The ITC method is implemented using DRAGON and OpenFOAM. • The ITC method is verified using a 1.5-D example. - Abstract: Coupling neutronic and thermal–hydraulic analyses of a nuclear reactor core is important because it helps identify the most relevant safety issues without conservative assumptions. Currently coupled computations solve the same governing equations using different coupling methods, which can be sorted into two categories: loose coupling and tight coupling. This paper proposes and verifies a third coupling approach called “the Integrated Tight Coupling (ITC) method”. The mathematical equations in the nuclear fuel are rearranged to be integrated via a novel concept of the energy-group function. In addition, the data from the neutron cross section library can be used directly. The ITC method is implemented using two open-source codes: the DRAGON code and OpenFOAM. Additionally, a coupled computation using these two codes is new and has not been done. The ITC method is verified using a 1.5-D (1-D neutronics and 2-D thermal–hydraulics) symmetric unit cell example. The mesh of the tightly integrated computation is 25% coarser than the loosely coupled one. Starting from a similar initial guess, the number of iterations for the ITC method is 24% fewer than that for the loosely coupled computation to reach the same accuracy. In addition, the ITC method is tested with different initial guesses. For all cases tested, the scheme converged to the same solution. With further improvement and additional testing, the ITC method has the potential to be incorporated with other neutronics and thermal–hydraulics codes.

Installation of the light tight cover for the SSD modules (the modules are behind the aluminium plate). The silicon sensors are sensitive to light tight, so ambient light will increase the noise and may even damage them.

CERN Multimedia

Nooren, G.

2004-01-01

Installation of the light tight cover for the SSD modules (the modules are behind the aluminium plate). The silicon sensors are sensitive to light tight , so ambient light will increase the noise and may even damage them.

Dielectric constant of graphene-on-polarized substrate: A tight ...

Indian Academy of Sciences (India)

Sivabrata Sahu

Corresponding author. E-mail: gcr@iopb.res.in. Published online 24 June 2017. Abstract. We report here a microscopic tight-binding theoretical study of the dynamic dielectric response of graphene-on-polarizable substrate with impurity. The Hamiltonian consists of first, second and third nearest- neighbour electron hopping ...

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

Norwegian gas on the European market

International Nuclear Information System (INIS)

Noreng, Oeystein

1999-01-01

Article. Norsk Hydro's acquisition of Saga has made the organization of Norwegian gas sales a very topical issue. Traditionally, Norwegian gas has been sold on long-term take-or-pay contracts where the sales volume is secured and the price is linked to the prices of other energy carriers, primarily oil. Norway has sold large volumes of gas to the continent and has an increasing share of the market. However, the long-term contracts place most of the price risk on the seller. Although the sale is guaranteed, earnings are low. Statoil, the largest seller of Norwegian gas, has so far earned much more by transporting the gas to the continent than by producing and selling it. The long-term take-or-pay contracts are no longer safe. In Germany, the power market is quickly opening for competition, implying falling prices and lapsing long-term contracts. A similar development is likely to occur in the gas market. From Norwegian quarters there has been little interest in establishing oneself in the gas markets on the continent, which worries the author. However, the traditional contracts will have to be renegotiated so that the prices will reflect the real competition in the market. It is argued that a sensible Norwegian strategy will be to prepare for a new world for gas, not to hold tight to historical positions. It is suggested that old plans to establish a gas transport company, Gassledd, should be revived. Such a company would be subject to the European Gas Directive and would have to admit a third party. It is likely that the Norwegian opposition to liberalization of the European gas market will one day appear poorly thought out, and that defensive considerations have overshadowed new opportunities

Tight-binding tunneling amplitude of an optical lattice

Science.gov (United States)

Arzamasovs, Maksims; Liu, Bo

2017-11-01

The particle in a periodic potential is an important topic in an undergraduate quantum mechanics curriculum and a stepping stone on the way to more advanced topics, such as courses on interacting electrons in crystalline solids, and graduate-level research in solid-state and condensed matter physics. The interacting many-body phenomena are usually described in terms of the second quantized lattice Hamiltonians which treat single-particle physics on the level of tight-binding approximation and add interactions on top of it. The aim of this paper is to show how the tight-binding tunneling amplitude can be related to the strength of the periodic potential for the case of a cosine potential used in the burgeoning field of ultracold atoms. We show how to approach the problem of computing the tunneling amplitude of a deep lattice using the JWKB (Jeffreys-Wentzel-Kramers-Brillouin, also known as semiclassical) approximation. We also point out that care should be taken when applying the method of the linear combination of atomic orbitals (LCAO) in an optical lattice context. A summary of the exact solution in terms of Mathieu functions is also given.

Tight-binding tunneling amplitude of an optical lattice

International Nuclear Information System (INIS)

Arzamasovs, Maksims; Liu, Bo

2017-01-01

The particle in a periodic potential is an important topic in an undergraduate quantum mechanics curriculum and a stepping stone on the way to more advanced topics, such as courses on interacting electrons in crystalline solids, and graduate-level research in solid-state and condensed matter physics. The interacting many-body phenomena are usually described in terms of the second quantized lattice Hamiltonians which treat single-particle physics on the level of tight-binding approximation and add interactions on top of it. The aim of this paper is to show how the tight-binding tunneling amplitude can be related to the strength of the periodic potential for the case of a cosine potential used in the burgeoning field of ultracold atoms. We show how to approach the problem of computing the tunneling amplitude of a deep lattice using the JWKB (Jeffreys–Wentzel–Kramers–Brillouin, also known as semiclassical) approximation. We also point out that care should be taken when applying the method of the linear combination of atomic orbitals (LCAO) in an optical lattice context. A summary of the exact solution in terms of Mathieu functions is also given. (paper)

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.

Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease.

Science.gov (United States)

Lerner, Aaron; Matthias, Torsten

2015-06-01

The incidence of autoimmune diseases is increasing along with the expansion of industrial food processing and food additive consumption. The intestinal epithelial barrier, with its intercellular tight junction, controls the equilibrium between tolerance and immunity to non-self-antigens. As a result, particular attention is being placed on the role of tight junction dysfunction in the pathogenesis of AD. Tight junction leakage is enhanced by many luminal components, commonly used industrial food additives being some of them. Glucose, salt, emulsifiers, organic solvents, gluten, microbial transglutaminase, and nanoparticles are extensively and increasingly used by the food industry, claim the manufacturers, to improve the qualities of food. However, all of the aforementioned additives increase intestinal permeability by breaching the integrity of tight junction paracellular transfer. In fact, tight junction dysfunction is common in multiple autoimmune diseases and the central part played by the tight junction in autoimmune diseases pathogenesis is extensively described. It is hypothesized that commonly used industrial food additives abrogate human epithelial barrier function, thus, increasing intestinal permeability through the opened tight junction, resulting in entry of foreign immunogenic antigens and activation of the autoimmune cascade. Future research on food additives exposure-intestinal permeability-autoimmunity interplay will enhance our knowledge of the common mechanisms associated with autoimmune progression. Copyright © 2015. Published by Elsevier B.V.

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.

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

Well test mathematical model for fractures network in tight oil reservoirs

Science.gov (United States)

Diwu, Pengxiang; Liu, Tongjing; Jiang, Baoyi; Wang, Rui; Yang, Peidie; Yang, Jiping; Wang, Zhaoming

2018-02-01

Well test, especially build-up test, has been applied widely in the development of tight oil reservoirs, since it is the only available low cost way to directly quantify flow ability and formation heterogeneity parameters. However, because of the fractures network near wellbore, generated from artificial fracturing linking up natural factures, traditional infinite and finite conductivity fracture models usually result in significantly deviation in field application. In this work, considering the random distribution of natural fractures, physical model of fractures network is proposed, and it shows a composite model feature in the large scale. Consequently, a nonhomogeneous composite mathematical model is established with threshold pressure gradient. To solve this model semi-analytically, we proposed a solution approach including Laplace transform and virtual argument Bessel function, and this method is verified by comparing with existing analytical solution. The matching data of typical type curves generated from semi-analytical solution indicates that the proposed physical and mathematical model can describe the type curves characteristic in typical tight oil reservoirs, which have up warping in late-term rather than parallel lines with slope 1/2 or 1/4. It means the composite model could be used into pressure interpretation of artificial fracturing wells in tight oil reservoir.

Preparation of environmental analyses for synfuel and unconventional gas technologies

Energy Technology Data Exchange (ETDEWEB)

Reed, R.M. (ed.)

1982-09-01

Government agencies that offer financial incentives to stimulate the commercialization of synfuel and unconventional gas technologies usually require an analysis of environmental impacts resulting from proposed projects. This report reviews potentially significant environmental issues associated with a selection of these technologies and presents guidance for developing information and preparing analyses to address these issues. The technologies considered are western oil shale, tar sand, coal liquefaction and gasification, peat, unconventional gas (western tight gas sands, eastern Devonian gas shales, methane from coal seams, and methane from geopressured aquifers), and fuel ethanol. Potentially significant issues are discussed under the general categories of land use, air quality, water use, water quality, biota, solid waste disposal, socioeconomics, and health and safety. The guidance provided in this report can be applied to preparation and/or review of proposals, environmental reports, environmental assessments, environmental impact statements, and other types of environmental analyses. The amount of detail required for any issue discussed must, by necessity, be determined on a case-by-case basis.

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.

Sit-Tight Syndrome and Tenure Elongation in African Politics ...

African Journals Online (AJOL)

The post-independence politics of African countries has been dominated by the phenomenon of sit-tight African heads of state and government who had acceeded to office by election or coup d'etat. This paper examines this recurring problem in post-independence African politics by examining its general and specific ...

Loose and Tight GNSS/INS Integrations: Comparison of Performance Assessed in Real Urban Scenarios.

Science.gov (United States)

Falco, Gianluca; Pini, Marco; Marucco, Gianluca

2017-01-29

Global Navigation Satellite Systems (GNSSs) remain the principal mean of positioning in many applications and systems, but in several types of environment, the performance of standalone receivers is degraded. Although many works show the benefits of the integration between GNSS and Inertial Navigation Systems (INSs), tightly-coupled architectures are mainly implemented in professional devices and are based on high-grade Inertial Measurement Units (IMUs). This paper investigates the performance improvements enabled by the tight integration, using low-cost sensors and a mass-market GNSS receiver. Performance is assessed through a series of tests carried out in real urban scenarios and is compared against commercial modules, operating in standalone mode or featuring loosely-coupled integrations. The paper describes the developed tight-integration algorithms with a terse mathematical model and assesses their efficacy from a practical perspective.

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)

Effect of rate, timing and placement of nitrogen on spring wheat in farmers' fields in the Yaqui Valley of Mexico

International Nuclear Information System (INIS)

Ortiz-Monasterio, I.; Naylor, R.

2000-01-01

The objective was to validate, in farmers' fields in the Yaqui Valley, N-management practices that had resulted, under experimental conditions, in reduction of trace-gas emissions while maintaining grain yield and quality. Trials were variously established in five different farmers' fields. The local management practice was compared with a new alternative, under various rates of N. The farmers managed all aspects of the trials, except for fertilizer application. The new N-management practice resulted in higher yield, protein and fertilizer recovery. The SPAD chlorophyll meter was found to be a promising tool for predicting grain-protein concentration. The method of application, broadcast vs. banding, did not affect fertilizer-N recovery. We conclude that it is possible to improve N-uptake efficiency in wheat grown in the Valley by delaying most of the N application close to the time of the first auxiliary irrigation. (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.

Relevant multi-setting tight Bell inequalities for qubits and qutrits

International Nuclear Information System (INIS)

Deng Dongling; Zhou Zisui; Chen Jingling

2009-01-01

In the celebrated paper [D. Collins, N. Gisin, J. Phys. A Math. Gen. 37 (2004) 1775], Collins and Gisin presented for the first time a three-setting Bell inequality (here we call it CG inequality for simplicity) which is relevant to the Clauser-Horne-Shimony-Holt (CHSH) inequality. Inspired by their brilliant ideas, we obtained some multi-setting tight Bell inequalities, which are relevant to the CHSH inequality and the CG inequality. Moreover, we generalized the method in the paper [J.L. Chen, D.L. Deng, Phys. Rev. A 79 (2009) 012115] to construct Bell inequality for qubits to higher dimensional system. Based on the generalized method, we present, for the first time, a three-setting tight Bell inequality for two qutrits, which is maximally violated by nonmaximally entangled states and relevant to the Collins-Gisin-Linden-Massar-Popescu inequality.

THE FAR-INFRARED, UV, AND MOLECULAR GAS RELATION IN GALAXIES UP TO z = 2.5

International Nuclear Information System (INIS)

Nordon, R.; Lutz, D.; Saintonge, A.; Berta, S.; Wuyts, S.; Förster Schreiber, N. M.; Genzel, R.; Magnelli, B.; Poglitsch, A.; Popesso, P.; Rosario, D.; Sturm, E.; Tacconi, L. J.

2013-01-01

We use the infrared excess (IRX) FIR/UV luminosity ratio to study the relation between the effective UV attenuation (A IRX ) and the UV spectral slope (β) in a sample of 450 1 * ) > 9.3. Thus, we are able to study galaxies on and even below the main SFR-stellar mass relation (main sequence). We find that main-sequence galaxies form a tight sequence in the IRX-β plane, which has a flatter slope than commonly used relations. This slope favors a Small-Magellanic-Cloud-like UV extinction curve, though the interpretation is model dependent. The scatter in the A IRX -β plane correlates with the position of the galaxies in the SFR-M * plane. Using a smaller sample of galaxies with CO gas masses, we study the relation between the UV attenuation and the molecular gas content. We find a very tight relation between the scatter in the IRX-β plane and the specific attenuation S A , a quantity that represents the attenuation contributed by the molecular gas mass per young star. S A is sensitive to both the geometrical arrangement of stars and dust and to the compactness of the star-forming regions. We use this empirical relation to derive a method for estimating molecular gas masses using only widely available integrated rest-frame UV and FIR photometry. The method produces gas masses with an accuracy between 0.12 and 0.16 dex in samples of normal galaxies between z ∼ 0 and z ∼ 1.5. Major mergers and submillimeter galaxies follow a different S A relation.

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.

Modulation of Tight Junction Structure and Function by Kinases and Phosphatases Targeting Occludin

Directory of Open Access Journals (Sweden)

Max Johannes Dörfel

2012-01-01

Full Text Available Tight junctions (TJs typically represent the most apical contacts in epithelial and endothelial cell layers where they play an essential role in the separation of extracellular or luminal spaces from underlying tissues in the body. Depending on the protein composition, TJs define the barrier characteristics and in addition maintain cell polarity. Two major families of integral membrane proteins form the typical TJ strand network, the tight junction-associated MARVEL protein (TAMP family members occludin, tricellulin, and MarvelD3 as well as a specific set of claudins. Occludin was the first identified member of these tetraspanins and is now widely accepted as a regulator of TJ assembly and function. Therefore, occludin itself has to be tightly regulated. Phosphorylation of occludin appears to be of central importance in this context. Here we want to summarize current knowledge on the kinases and phosphatases directly modifying occludin, and their role in the regulation of TJ structure, function, and dynamics.

Radioactive gas storage device

International Nuclear Information System (INIS)

Seki, Eiji; Kobayashi, Yoshihiro.

1989-01-01

The present invention concerns a device of ionizing radioactive gases to be processed in gaseous nuclear fission products in nuclear fuel reprocessing plants, etc., and injecting them into metal substrates for storage. The device comprises a vessel for a tightly closed type outer electrode in which gases to be processed are introduced, an electrode disposed to the inside of the vessel and the target material, a high DC voltage power source for applying high voltage to the electrodes, etc. There are disposed a first electric discharging portion for preparting discharge plasma for ion injection of different electrode distance and a second electric discharging portion for causing stable discharge between the vessel and the electrode. The first electric discharging portion for the ion injection provides an electrode distance suitable to acceleration sputtering and the second electric discharging portion is used for stable discharge. Accordingly, if the gas pressure in the radioactive gas storage device is reduced by the external disturbance, etc., since the second electric discharging portion satisfies the electric discharging conditions, the device can continue electric discharge. (K.M.)

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

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

Northern gas : Arctic Canada and Alaska

International Nuclear Information System (INIS)

Constantin, D.

2005-01-01

This paper discusses supply challenges in relation to Northern gas availability in Arctic Canada and Alaska. A background of BP Canada Energy Company was provided. It was suggested that gas from traditional North American basins would not meet demand, and that incremental sources of supply would be needed. A map of traditional and non-tradition supply sources was presented along with details of supply and infrastructure investment requirements from 2003-2025. The roles of producers, local distribution companies, pipelines and policy makers in infrastructure development were examined. Potential resources in Alaska and the Mackenzie Delta were discussed, along with details of the Mackenzie Valley Pipeline project and exploration activities. Alaska's North Slope gas resource was reviewed. Several large projects devolving from the Alaska Gas Pipeline represent an anticipated total investment of $20 billion. Various regulatory and economic conditions necessary for the successful completion of the project include the Alaska Fiscal Contract; Alaska gas provisions in the Federal Energy Bill; details of the Canadian regulatory process; and cost reductions and market outlooks. It was concluded that the Alaska Gas Pipeline would provide thousands of jobs and provide stability of long-term gas prices as well as meeting North America's energy needs. In addition, the pipeline would provide $16 billion in Canadian government revenues and $40 billion in US government revenues. The pipeline would provide 4.5 billion cubic feet per day of clean energy, with half the carbon dioxide emissions of coal. It would also provide hundreds of billions of dollars in consumer savings. tabs, figs

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

Diagnosing the tight building syndrome

Energy Technology Data Exchange (ETDEWEB)

Rogers, S.A.

1987-12-01

Formaldehyde is but one of many chemicals capable of causing the tight building syndrome or environmentally induced illness (EI). The spectrum of symptoms it may induce includes attacks of headache, flushing, laryngitis, dizziness, nausea, extreme weakness, arthralgia, unwarranted depression, dysphonia, exhaustion, inability to think clearly, arrhythmia or muscle spasms. The nonspecificity of such symptoms can baffle physicians from many specialties. Presented herein is a simple office method for demonstrating that formaldehyde is among the etiologic agents triggering these symptoms. The very symptoms that patients complain of can be provoked within minutes, and subsequently abolished, with an intradermal injection of the appropriate strength of formaldehyde. This injection aids in convincing the patient of the cause of the symptoms so he can initiate measure to bring his disease under control.

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.

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.

CHARACTERIZATION OF TIGHTLY-ASSOCIATED SMOOTH MUSCLE MYOSIN-MYOSIN LIGHT CHAIN KINASE-CALMODULIN COMPLEXES*

OpenAIRE

Hong, Feng; Haldeman, Brian D.; John, Olivia A.; Brewer, Paul D.; Wu, Yi-Ying; Ni, Shaowei; Wilson, David P.; Walsh, Michael P.; Baker, Jonathan E.; Cremo, Christine R.

2009-01-01

A current popular model to explain phosphorylation of smooth muscle myosin (SMM) by smooth muscle myosin light chain kinase (MLCK) proposes that MLCK is bound tightly to actin but weakly to SMM. We found that MLCK and calmodulin (CaM) co-purify with unphosphorylated SMM (up-SMM) from chicken gizzard, suggesting that they are tightly bound. Although the MLCK:SMM molar ratio in SMM preparations was well below stoichiometric (1:73 ± 9), the ratio was ~ 23–37% of that in gizzard tissue. Fifteen t...

FDTD approach to optical forces of tightly focused vector beams on metal particles.

Science.gov (United States)

Qin, Jian-Qi; Wang, Xi-Lin; Jia, Ding; Chen, Jing; Fan, Ya-Xian; Ding, Jianping; Wang, Hui-Tian

2009-05-11

We propose an improved FDTD method to calculate the optical forces of tightly focused beams on microscopic metal particles. Comparison study on different kinds of tightly focused beams indicates that trapping efficiency can be altered by adjusting the polarization of the incident field. The results also show the size-dependence of trapping forces exerted on metal particles. Transverse tapping forces produced by different illumination wavelengths are also evaluated. The numeric simulation demonstrates the possibility of trapping moderate-sized metal particles whose radii are comparable to wavelength.

Non-proximate mass spectrometry using a heated 1-m long PTFE tube and an air-tight APCI ion source

International Nuclear Information System (INIS)

Usmanov, Dilshadbek T.; Hiraoka, Kenzo; Wada, Hiroshi; Matsumura, Masaya; Sanada-Morimura, Sachiyo; Nonami, Hiroshi; Yamabe, Shinichi

2017-01-01

Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 °C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device. Analytes were ionized by an ac corona discharge located at 1.5 mm from the inlet of the mass spectrometer. By using the airtight ion source, all the ionized gas in the ion source was introduced into the vacuum of the mass spectrometer via only the evacuation of the mass spectrometer (1.6 l min"−"1). Sub-pg limits of detection were obtained for carbaryl and trinitrotoluene. Owing to its flexibility and high sensitivity, the sniffing tube coupled with a mass spectrometer can be used as the stethoscope for the high-sensitive gas analysis. The experimental results obtained for drugs, hydrogen peroxide and small alkanes were discussed by DFT calculations. - Highlights: • Non-proximate mass spectrometry for the trace-level gas analysis was developed. • Using a 1-m long flexible PTFE tube, it can be applicable to complicated-shape real-world samples. • By atmospheric pressure chemical ionization in the airtight ion source, sub-pg limits of detection were attained. • Adsorption of less-volatility compounds was negligible with the tube temperature at 130° C. • Novel experimental results obtained were fully examined by density functional theory calculations.

Non-proximate mass spectrometry using a heated 1-m long PTFE tube and an air-tight APCI ion source

Energy Technology Data Exchange (ETDEWEB)

Usmanov, Dilshadbek T. [Clean Energy Research Center, University of Yamanashi, Takeda-4, Kofu, Yamanashi, 400-8511 (Japan); Institute of Ion-Plasma and Laser Technologies, Durmon Yoli Street 33, 100125, Tashkent (Uzbekistan); Hiraoka, Kenzo, E-mail: hiraoka@yamanashi.ac.jp [Clean Energy Research Center, University of Yamanashi, Takeda-4, Kofu, Yamanashi, 400-8511 (Japan); Wada, Hiroshi [Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, 496 Izumi, Chikugo, Fukuoka 833-0041 (Japan); Matsumura, Masaya; Sanada-Morimura, Sachiyo [Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, Suya 2421, shiKo, Kumamoto 861-1192 (Japan); Nonami, Hiroshi [Plant Biophysics/Biochemistry Research Laboratory, Faculty of Agriculture, Ehime University, 3-5-7 T Tarumi, 790-0905, Matsuyama (Japan); Yamabe, Shinichi, E-mail: yamabesh@gmail.com [Department of Material Science, Nara Institute of Science and Technology, Takayama-cho, 8916-5, Ikoma, Nara, 630−0101 (Japan)

2017-06-22

Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 °C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device. Analytes were ionized by an ac corona discharge located at 1.5 mm from the inlet of the mass spectrometer. By using the airtight ion source, all the ionized gas in the ion source was introduced into the vacuum of the mass spectrometer via only the evacuation of the mass spectrometer (1.6 l min{sup −1}). Sub-pg limits of detection were obtained for carbaryl and trinitrotoluene. Owing to its flexibility and high sensitivity, the sniffing tube coupled with a mass spectrometer can be used as the stethoscope for the high-sensitive gas analysis. The experimental results obtained for drugs, hydrogen peroxide and small alkanes were discussed by DFT calculations. - Highlights: • Non-proximate mass spectrometry for the trace-level gas analysis was developed. • Using a 1-m long flexible PTFE tube, it can be applicable to complicated-shape real-world samples. • By atmospheric pressure chemical ionization in the airtight ion source, sub-pg limits of detection were attained. • Adsorption of less-volatility compounds was negligible with the tube temperature at 130° C. • Novel experimental results obtained were fully examined by density functional theory calculations.

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...

Jack-knife stretching promotes flexibility of tight hamstrings after 4 weeks: a pilot study.

Science.gov (United States)

Sairyo, Koichi; Kawamura, Takeshi; Mase, Yasuyoshi; Hada, Yasushi; Sakai, Toshinori; Hasebe, Kiyotaka; Dezawa, Akira

2013-08-01

Tight hamstrings are reported to be one of the causes of low back pain. However, there have been few reports on effective stretching procedures for the tight hamstrings. The so-called jack-knife stretch, an active-static type of stretching, can efficiently increase the flexibility of tight hamstrings. To evaluate hamstring tightness before and after the 4-week stretching protocol in healthy volunteer adults and patients aged under 18 years with low back pain. For understanding the hamstrings tightness, we measured two parameters including (1) finger to floor distance (FFD) and (2) pelvis forward inclination angle (PFIA). Eight healthy adult volunteers who had no lumbar or hip problems participated in this study (mean age: 26.8 years). All lacked flexibility and their FFD were positive before the experiment. Subjects performed 2 sets of the jack-knife stretch every day for 4 weeks. One set consisted of 5 repetitions, each held for 5 s. Before and during the 4-week experiment, the FFD and PFIA of toe-touching tests were measured weekly. For 17 of the sports players aged under 18, only FFD was measured. In adult volunteers, FFD was 14.1 ± 6.1 cm before the experiment and decreased to -8.1 ± 3.7 cm by the end of week 4, indicating a gain in flexibility of 22.2 cm. PFIA was 50.6 ± 8.2 before the experiment and 83.8 ± 5.8 degrees after. Before and after the experiment, the differences were significant (p hamstrings.

A hydrogen leak-tight, transparent cryogenic sample container for ultracold-neutron transmission measurements

Science.gov (United States)

Döge, Stefan; Hingerl, Jürgen

2018-03-01

The improvement of the number of extractable ultracold neutrons (UCNs) from converters based on solid deuterium (sD2) crystals requires a good understanding of the UCN transport and how the crystal's morphology influences its transparency to the UCNs. Measurements of the UCN transmission through cryogenic liquids and solids of interest, such as hydrogen (H2) and deuterium (D2), require sample containers with thin, highly polished and optically transparent windows and a well defined sample thickness. One of the most difficult sealing problems is that of light gases like hydrogen and helium at low temperatures against high vacuum. Here we report on the design of a sample container with two 1 mm thin amorphous silica windows cold-welded to aluminum clamps using indium wire gaskets, in order to form a simple, reusable, and hydrogen-tight cryogenic seal. The container meets the above-mentioned requirements and withstands up to 2 bar hydrogen gas pressure against isolation vacuum in the range of 10-5 to 10-7 mbar at temperatures down to 4.5 K. Additionally, photographs of the crystallization process are shown and discussed.

A hydrogen leak-tight, transparent cryogenic sample container for ultracold-neutron transmission measurements.

Science.gov (United States)

Döge, Stefan; Hingerl, Jürgen

2018-03-01

The improvement of the number of extractable ultracold neutrons (UCNs) from converters based on solid deuterium (sD 2 ) crystals requires a good understanding of the UCN transport and how the crystal's morphology influences its transparency to the UCNs. Measurements of the UCN transmission through cryogenic liquids and solids of interest, such as hydrogen (H 2 ) and deuterium (D 2 ), require sample containers with thin, highly polished and optically transparent windows and a well defined sample thickness. One of the most difficult sealing problems is that of light gases like hydrogen and helium at low temperatures against high vacuum. Here we report on the design of a sample container with two 1 mm thin amorphous silica windows cold-welded to aluminum clamps using indium wire gaskets, in order to form a simple, reusable, and hydrogen-tight cryogenic seal. The container meets the above-mentioned requirements and withstands up to 2 bar hydrogen gas pressure against isolation vacuum in the range of 10 -5 to 10 -7 mbar at temperatures down to 4.5 K. Additionally, photographs of the crystallization process are shown and discussed.

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

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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.

Nucleation and growth of new particles in Po Valley, Italy

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A. Hamed

2007-01-01

Full Text Available Aerosol number distribution measurements are reported at San Pietro Capofiume (SPC station (44°39' N, 11°37' E for the time period 2002–2005. The station is located in Po Valley, the largest industrial, trading and agricultural area in Italy with a high population density. New particle formation was studied based on observations of the particle size distribution, meteorological and gas phase parameters. The nucleation events were classified according to the event clarity based on the particle number concentrations, and the particle formation and growth rates. Out of a total of 769 operational days from 2002 to 2005 clear events were detected on 36% of the days whilst 33% are clearly non-event days. The event frequency was high during spring and summer months with maximum values in May and July, whereas lower frequency was observed in winter and autumn months. The average particle formation and growth rates were estimated as ~6 cm−3 s−1 and ~7 nm h−1, respectively. Such high growth and formation rates are typical for polluted areas. Temperature, wind speed, solar radiation, SO2 and O3 concentrations were on average higher on nucleation days than on non-event days, whereas relative and absolute humidity and NO2 concentration were lower; however, seasonal differences were observed. Backtrajectory analysis suggests that during majority of nucleation event days, the air masses originate from northern to eastern directions. We also study previously developed nucleation event correlations with environmental variables and show that they predict Po Valley nucleation events with variable success.

Strain-dependent augmentation of tight-junction barrier function in human primary epidermal keratinocytes by Lactobacillus and Bifidobacterium lysates.

Science.gov (United States)

Sultana, Reshma; McBain, Andrew J; O'Neill, Catherine A

2013-08-01

In this study, we investigated whether probiotic lysates can modify the tight-junction function of human primary keratinocytes. The keratinocytes were grown on cell culture inserts and treated with lysates from Bifidobacterium longum, Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus fermentum, or Lactobacillus rhamnosus GG. With the exception of L. fermentum (which decreased cell viability), all strains markedly enhanced tight-junction barrier function within 24 h, as assessed by measurements of transepithelial electrical resistance (TEER). However, B. longum and L. rhamnosus GG were the most efficacious, producing dose-dependent increases in resistance that were maintained for 4 days. These increases in TEER correlated with elevated expression of tight-junction protein components. Neutralization of Toll-like receptor 2 abolished both the increase in TEER and expression of tight-junction proteins induced by B. longum, but not L. rhamnosus GG. These data suggest that some bacterial strains increase tight-junction function via modulation of protein components but the different pathways involved may vary depending on the bacterial strain.

Effects of Tight Versus Non Tight Control of Metabolic Acidosis on Early Renal Function After Kidney Transplantation

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Farhad Etezadi

2012-09-01

Full Text Available Background Recently, several studies have been conducted to determine the optimal strategy for intraoperative fluid replacement therapy in renal transplantation surgery. Since infusion of sodium bicarbonate as a buffer seems to be safer than other buffer compounds (lactate, gluconate, acetatethat indirectly convert into it within the liver, We hypothesized tight control of metabolic acidosis by infusion of sodium bicarbonate may improve early post-operative renal function in renal transplant recipients. Methods:120 patients were randomly divided into two equal groups. In group A, bicarbonate was infused intra-operatively according to Base Excess (BE measurements to achieve the normal values of BE (5 to +5 mEq/L. In group B, infusion of bicarbonate was allowed only in case of severe metabolic acidosis (BE [less than or equal to] 15 mEq/L or bicarbonate [less than or equal to] 10 mEq/L or PH [less than or equal to] 7.15. Minute ventilation was adjusted to keep PaCO2 within the normal range. Primary end-point was sampling of serum creatinine level in first, second, third and seventh post-operative days for statistical comparison between groups. Secondary objectives were comparison of cumulative urine volumes in the first 24 h of post-operative period and serum BUN levels which were obtained in first, second, third and seventh post-operative days. Results:In group A, all of consecutive serum creatinine levels were significantly lower in comparison with group B. With regard to secondary outcomes, no significant difference between groups was observed. Conclusion:Intra-operative tight control of metabolic acidosis by infusion of Sodium Bicarbonate in renal transplant recipients may improve early post-operative renal function.