WorldWideScience

Sample records for barrier emplacement experiment

  1. Visualization experiment to investigate capillary barrier performance in the context of a Yucca Mountain emplacement drift.

    Science.gov (United States)

    Tidwell, Vincent C; Glass, Robert J; Chocas, Connie; Barker, Glenn; Orear, Lee

    2003-01-01

    The use of capillary barriers as engineered backfill systems to divert water away from radioactive waste potentially stored in a Yucca Mountain emplacement drift is investigated. We designed and conducted a flow visualization experiment to investigate capillary barrier performance in this context. A two-dimensional, thin slab, test system replicated the physical emplacement drift to one-quarter scale (1.4-m diameter) and included the simulated drift wall, waste canister, pedestal, capillary barrier backfill, and host-rock fracture system. Water was supplied at the top of the simulated drift and allowed to discharge by way of wicks located along the left wall of the cell (simulated fractures) or by a gravity drain at the bottom of the right side (simulated impermeable rock with floor drain). Photographs captured the migration of water and a blue dye tracer within the system, analytical balances measured the mass balance of water, while tensiometers measured the capillary pressure at numerous locations. Of particular concern to this test was the drainage of the capillary barrier, which terminates against the drift wall. We found that while the simulated fractures (left side) and drain (right side) each influenced the performance of the capillary barrier at early time, they had little differential affect at later times. Also of concern was the small disparity in capillary properties between the fine and coarse layer (limited by the need of a fine-grained material that would not filter into the coarse layer under dry conditions). While the capillary barrier was able to divert the majority of flow toward the edges of the system and away from the simulated waste canister, the barrier did not preclude flow in the coarse layer, which was noted to be visually wet next to the waste canister on day 92 and was continuing to take on water at termination on day 112.

  2. Mont Terri Project - Engineered barrier emplacement experiment in Opalinus Clay for the disposal of radioactive waste in underground repositories

    Energy Technology Data Exchange (ETDEWEB)

    Mayor, J. C. [Empresa Nacional de Residuos Radioactivos SA (ENRESA), Madrid (Spain); Garcia-Sineriz, J. [Asociacion para la Investigacion y Desarollo Industrial de los Recursos Naturales (AITEMIN), Madrid (Spain); Alonso, E. [Centre Internacional de Metodos Numerics en Ingenyeria (CIMNE), Barcelona (Spain); Alheid, H.-J. [Bundesanstalt fuer Geowissenschaften und Rohstoffe (BGR), Hannover (Germany); Bluemling, P. [National Cooperative for the Disposal of Radioactive Waste (Nagra), Wettingen (Switzerland)

    2007-07-01

    The Engineered Barrier (EB) experiment was a full-scale test for the demonstration, in a horizontal drift, of an emplacement technics of the clay barrier, using a granular bentonite material in the upper part of this barrier and bentonite blocks at the bottom. The test has been carried out in a 6 m long section of a niche excavated in Opalinus Clay of the Mont Terri underground laboratory. A steel dummy canister, with the same dimensions and weight as the real reference canisters, was placed on top of a bed of highly compacted bentonite blocks (in turn lying on a concrete bed), and the rest of the clay barrier volume was backfilled with a Granular Bentonite Material (GBM), made of very highly compacted pellets of different sizes. Hydro-mechanical instrumentation and an artificial hydration system (to accelerate the saturation of the clay barrier) were installed, and the test section sealed with a concrete plug. The evolution of the hydro-mechanical parameters along the hydration, both in the barrier and in the clayey rock formation, has been monitored during about 1.5 years, and modelled using the CODE-BRIGHT code. The EB experiment has proved that fully automated production of a Granular Bentonite Material (GBM) is possible and large quantities can be produced in due time in the required quality. Only minor modifications of existing production lines in industry for other applications were necessary to achieve this result. In the EB test section, a dry density of 1.36 g/cm{sup 3} of the emplaced GBM has been obtained. With this value it is estimated that the hydraulic conductivity of this material is lower than 5 x 10{sup -12} m/s and the swelling pressure is about 1.3 MPa. Even though the EB test section conditions are now not considered as representative of a true demonstration, it is deemed that the model emplacement testing results (dry density of about 1.40 g/cm{sup 3}) serve well to demonstrate the achievable densities expected in the real world setting. The

  3. Barrier experiment: Shock initiation under complex loading

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-12

    The barrier experiments are a variant of the gap test; a detonation wave in a donor HE impacts a barrier and drives a shock wave into an acceptor HE. The question we ask is: What is the trade-off between the barrier material and threshold barrier thickness to prevent the acceptor from detonating. This can be viewed from the perspective of shock initiation of the acceptor subject to a complex pressure drive condition. Here we consider key factors which affect whether or not the acceptor undergoes a shock-to-detonation transition. These include the following: shock impedance matches for the donor detonation wave into the barrier and then the barrier shock into the acceptor, the pressure gradient behind the donor detonation wave, and the curvature of detonation front in the donor. Numerical simulations are used to illustrate how these factors affect the reaction in the acceptor.

  4. Compositional evolution of the emplaced fuel source in the vadose zone field experiment at airbase Vaerlose, Denmark

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Christophersen, Mette; Maier, U.;

    2005-01-01

    A field experiment was performed in a sandy vadose zone, studying the fate of an emplaced fuel-NAPL source, composed of 13 hydrocarbons and a tracer. The UNIFAC model was used to test the nonideal behavior of the source, and the numerical model MIN3P was used for assessing the effect of biodegrad......A field experiment was performed in a sandy vadose zone, studying the fate of an emplaced fuel-NAPL source, composed of 13 hydrocarbons and a tracer. The UNIFAC model was used to test the nonideal behavior of the source, and the numerical model MIN3P was used for assessing the effect...... of biodegradation on source evolution. The diffusive loss to the surrounding vadose zone and the atmosphere created temporary gradients in mole fractions of the individual compounds within the source NAPL. The evolution of the source composition corresponded in general with expectations based on Raoult's Law....... Positive deviations were calculated for the aromatic compounds. The effect of biodegradation on source depletion, evaluated by numerical modeling, was greater for the aromatic as compared to the aliphatic compounds. Hence, the faster depletion of the aromatic relative to aliphatic compounds of similar...

  5. Assessing uncertainties in remotely sensed lava flow emplacement - results from an indoor analog experiment

    Science.gov (United States)

    Pick, Leonie; Zakšek, Klemen; Lombardo, Valerio; Hort, Matthias

    2016-04-01

    Infrared satellite images are an easily accessible data source for monitoring the radiant power (RP) emitted from lava flows during effusive eruptions in close to real time. Although not necessary for RP estimations, lava temperature is a crucial parameter in the determination of the flow's convected heat. In conjunction with the flow's spatial extent it assists the identification of potentially threatened areas and thereby the overall lava inundation hazard assessment. The accurate determination of the flow's size and temperature is however afflicted with uncertainty as the lava occupies only a small fraction (wire temperatures corresponding to barely glowing (experiment 1), glowing (experiment 2) and strongly glowing (experiment 3) was confirmed. The deviation of the hotspot's pixel fraction yielded by the Dual-Band method from the theoretically calculated one was found to be within the expected limits given that the hotspot is larger than about 3 % of the pixel area, a resolution boundary most remotely sensed volcanic hotspots fall below.

  6. SUBSURFACE EMPLACEMENT TRANSPORTATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    T. Wilson; R. Novotny

    1999-11-22

    The objective of this analysis is to identify issues and criteria that apply to the design of the Subsurface Emplacement Transportation System (SET). The SET consists of the track used by the waste package handling equipment, the conductors and related equipment used to supply electrical power to that equipment, and the instrumentation and controls used to monitor and operate those track and power supply systems. Major considerations of this analysis include: (1) Operational life of the SET; (2) Geometric constraints on the track layout; (3) Operating loads on the track; (4) Environmentally induced loads on the track; (5) Power supply (electrification) requirements; and (6) Instrumentation and control requirements. This analysis will provide the basis for development of the system description document (SDD) for the SET. This analysis also defines the interfaces that need to be considered in the design of the SET. These interfaces include, but are not limited to, the following: (1) Waste handling building; (2) Monitored Geologic Repository (MGR) surface site layout; (3) Waste Emplacement System (WES); (4) Waste Retrieval System (WRS); (5) Ground Control System (GCS); (6) Ex-Container System (XCS); (7) Subsurface Electrical Distribution System (SED); (8) MGR Operations Monitoring and Control System (OMC); (9) Subsurface Facility System (SFS); (10) Subsurface Fire Protection System (SFR); (11) Performance Confirmation Emplacement Drift Monitoring System (PCM); and (12) Backfill Emplacement System (BES).

  7. Solar energy emplacement developer

    Science.gov (United States)

    Mortensen, Michael; Sauls, Bob

    1991-01-01

    A preliminary design was developed for a Lunar Power System (LPS) composed of photovoltaic arrays and microwave reflectors fabricated from lunar materials. The LPS will collect solar energy on the surface of the Moon, transform it into microwave energy, and beam it back to Earth where it will be converted into usable energy. The Solar Energy Emplacement Developer (SEED) proposed will use a similar sort of solar energy collection and dispersement to power the systems that will construct the LPS.

  8. Drip Shield Emplacement Gantry Concept

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.A.; Cron, J.

    2000-03-29

    This design analysis has shown that, on a conceptual level, the emplacement of drip shields is feasible with current technology and equipment. A plan for drip shield emplacement was presented using a Drip Shield Transporter, a Drip Shield Emplacement Gantry, a locomotive, and a Drip Shield Gantry Carrier. The use of a Drip Shield Emplacement Gantry as an emplacement concept results in a system that is simple, reliable, and interfaces with the numerous other exising repository systems. Using the Waste Emplacement/Retrieval System design as a basis for the drip shield emplacement concept proved to simplify the system by using existing equipment, such as the gantry carrier, locomotive, Electrical and Control systems, and many other systems, structures, and components. Restricted working envelopes for the Drip Shield Emplacement System require further consideration and must be addressed to show that the emplacement operations can be performed as the repository design evolves. Section 6.1 describes how the Drip Shield Emplacement System may use existing equipment. Depending on the length of time between the conclusion of waste emplacement and the commencement of drip shield emplacement, this equipment could include the locomotives, the gantry carrier, and the electrical, control, and rail systems. If the exisiting equipment is selected for use in the Drip Shield Emplacement System, then the length of time after the final stages of waste emplacement and start of drip shield emplacement may pose a concern for the life cycle of the system (e.g., reliability, maintainability, availability, etc.). Further investigation should be performed to consider the use of existing equipment for drip shield emplacement operations. Further investigation will also be needed regarding the interfaces and heat transfer and thermal effects aspects. The conceptual design also requires further design development. Although the findings of this analysis are accurate for the assumptions made

  9. TRANSPORT AND EMPLACEMENT EQUIPMENT DESCRIPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    1997-09-29

    The objective and the scope of this document are to list and briefly describe the major mobile equipment necessary for waste package (WP) Transport and Emplacement in the proposed subsurface nuclear waste repository at Yucca Mountain. Primary performance characteristics and some specialized design features of the equipment are explained and summarized in the individual subsections of this document. The Transport and Emplacement equipment described in this document consists of the following: (1) WP Transporter; (2) Reusable Rail Car; (3) Emplacement Gantry; (4) Gantry Carrier; and (5) Transport Locomotive.

  10. Renewable Energy Permitting Barriers in Hawaii: Experience from the Field

    Energy Technology Data Exchange (ETDEWEB)

    Busche, S.; Donnelly, C.; Atkins, D.; Fields, R.; Black, C.

    2013-03-01

    This white paper presents a summary of the solicited input from permitting agencies and renewable energy developers on the permitting process in Hawaii to provide stakeholders in Hawaii, particularly those involved in permitting, with information on current permitting barriers that renewable energy developers are experiencing.

  11. Current experience with renal transplantation across the ABO barrier.

    Science.gov (United States)

    Nelson, P W; Helling, T S; Shield, C F; Beck, M; Bryan, C F

    1992-11-01

    Solid organ transplantation has traditionally been governed by the rules of blood group compatibility. Thus, it has been demonstrated that crossing the ABO blood group barrier generally results in hyperacute rejection. However, the A2 subtype of the blood group A is a weaker antigen. Under certain circumstances, organs from donors with blood group A2 can be transplanted across the ABO blood group barrier into recipients of O or B blood type. Since 1986, 33 patients including 24 blood group O and 9 blood group B patients received A2 (30) or A2B (3) donor kidneys. Both cadaver donor (31) and living-related grafts (2) have been undertaken. The mean follow-up since transplantation for the 21 patients with functioning grafts is 36 months, with a 67.2% current graft survival. Immunosuppression for these transplants consisted of azathioprine, prednisone, and cyclosporine, often in combination with prophylactic OKT3 or antilymphocyte globulin as protocol dictated. Special immunosuppressive protocols such as splenectomy or plasmapheresis were not used. The serum of the potential recipient was analyzed for immunoglobulin G (IgG) and immunoglobulin M (IgM) forms of antibody against A1 and A2 red blood cells. There is a strong correlation between a low (less than or equal to 1:8) anti-A1 IgG titer and both early and long-term graft function. Recipients with an IgG titer greater than 1:8 in the pretransplant serum had a much higher incidence of early graft failure. We no longer recommend transplantation of A2 kidneys into O or B recipients with a pretransplant titer of greater than 1:8 but found that recipients with low titers have graft function rates essentially equal to those of ABO-compatible patients. Patients with blood group B have, over time, lower anti-A IgG titers than do blood group O patients. In addition, the graft survival among blood group B patients is 89% compared with 58% among group O recipients. This may be due to the generally low titers found in blood

  12. Plasma diagnostic techniques in thermal-barrier tandem-mirror fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silver, E.H.; Clauser, J.F.; Carter, M.R.; Failor, B.H.; Foote, J.H.; Hornady, R.S.; James, R.A.; Lasnier, C.J.; Perkins, D.E.

    1986-08-29

    We review two classes of plasma diagnostic techniques used in thermal-barrier tandem-mirror fusion experiments. The emphasis of the first class is to study mirror-trapped electrons at the thermal-barrier location. The focus of the second class is to measure the spatial and temporal behavior of the plasma space potential at various axial locations. The design and operation of the instruments in these two categories are discussed and data that are representative of their performance is presented.

  13. Reactive barrier system for nitrate removal from mine effluents in northern Sweden: Laboratory experiments

    Science.gov (United States)

    Herbert, Roger

    2010-05-01

    Laboratory column experiments have been conducted to determine nitrate removal rates from mine effluents by denitrification, with the purpose of providing initial data for the construction of a pilot scale reactive barrier system at the Malmberget iron mine, Sweden. Experiments were conducted at several different flow rates at 5C, 10C and room temperature; annual mean temperatures at the Malmberget site lie close to 0C. Columns were filled with an organic substrate consisting of sawdust mixed with sewage sludge, the source of denitrifying bacteria, supported by oven-dried clay pellets. Apparent denitrification rates, calculated from inflow and outflow nitrate concentrations and column hydraulic residence time, ranged from 5 to 13 mg N/L/d, with the lowest rates corresponding to the 5C experiments. These rates are, however, limited to a certain degree by the low flow rate and the supply of electrons acceptors (i.e. nitrate) to denitrifying bacteria. Results from the column experiment have been used to construct a barrier system in Malmberget, Sweden. Trial runs with the pilot-scale barrier will be conducted during 2010, with the purpose of determining the performance of the barrier as mean air temperatures increase from below to above 0C and saturated flow commences in the barrier. The barrier system is constructed as a rectangular container with steel sheet walls (9m length in flow direction, 1.5m deep), and the flow rate will be adjusted to a hydraulic residence time of 1 day. The pilot-scale barrier system currently lies above ground, but a permanent barrier system would be installed below the ground surface so that the system can be maintained at positive temperatures throughout the year.

  14. Redefining Authentic Research Experiences in Introductory Biology Laboratories and Barriers to Their Implementation

    Science.gov (United States)

    Spell, Rachelle M.; Guinan, Judith A.; Miller, Kristen R.; Beck, Christopher W.

    2014-01-01

    Incorporating authentic research experiences in introductory biology laboratory classes would greatly expand the number of students exposed to the excitement of discovery and the rigor of the scientific process. However, the essential components of an authentic research experience and the barriers to their implementation in laboratory classes are…

  15. Handling and Emplacement Options for Deep Borehole Disposal Conceptual Design.

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hardin, Ernest [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    This report presents conceptual design information for a system to handle and emplace packages containing radioactive waste, in boreholes 16,400 ft deep or possibly deeper. Its intended use is for a design selection study that compares the costs and risks associated with two emplacement methods: drill-string and wireline emplacement. The deep borehole disposal (DBD) concept calls for siting a borehole (or array of boreholes) that penetrate crystalline basement rock to a depth below surface of about 16,400 ft (5 km). Waste packages would be emplaced in the lower 6,560 ft (2 km) of the borehole, with sealing of appropriate portions of the upper 9,840 ft (3 km). A deep borehole field test (DBFT) is planned to test and refine the DBD concept. The DBFT is a scientific and engineering experiment, conducted at full-scale, in-situ, without radioactive waste. Waste handling operations are conceptualized to begin with the onsite receipt of a purpose-built Type B shipping cask, that contains a waste package. Emplacement operations begin when the cask is upended over the borehole, locked to a receiving flange or collar. The scope of emplacement includes activities to lower waste packages to total depth, and to retrieve them back to the surface when necessary for any reason. This report describes three concepts for the handling and emplacement of the waste packages: 1) a concept proposed by Woodward-Clyde Consultants in 1983; 2) an updated version of the 1983 concept developed for the DBFT; and 3) a new concept in which individual waste packages would be lowered to depth using a wireline. The systems described here could be adapted to different waste forms, but for design of waste packaging, handling, and emplacement systems the reference waste forms are DOE-owned high- level waste including Cs/Sr capsules and bulk granular HLW from fuel processing. Handling and Emplacement Options for Deep Borehole Disposal Conceptual Design July 23, 2015 iv ACKNOWLEDGEMENTS This report has

  16. Barriers to Conducting Supervised Agricultural Experiences as Perceived by Preservice Agricultural Education Teachers

    Directory of Open Access Journals (Sweden)

    J. Joey Blackburn

    2014-10-01

    Full Text Available The purpose of this descriptive study was to assess preservice agriculture teachers’ perceptions of the importance of Supervised Agricultural Experience (SAE and their views on barriers to conducting SAE. A census of the sophomore-level agricultural education course at Oklahoma State University was conducted to measure perceptions at the beginning and end of the course. This study was framed upon Ajzen’s Theory of Planned Behavior. Results indicated that preservice teachers perceived SAE was an important component of agricultural education and important at the secondary school they attended. The greatest barrier to conducting SAE was their lack of familiarity with newer SAE categories. This was true at both the beginning and end of the course. It is recommended that preservice teachers receive instruction on and experiences in all types of SAE. This would increase the likelihood of preservice teachers perceiving they have control over this barrier regarding SAE implementation. This cohort of preservice teachers should be surveyed over time to determine change in their perceptions of barriers to SAE implementation as they progress in the agricultural education program and through their careers. Further, the views of in-service teachers should also be assessed to determine if perceived barriers differ with professional experience.

  17. The barriers to sustaining and scaling-up housing experiments in community-care: the dutch experience

    NARCIS (Netherlands)

    Cramer, H.J.; Voordijk, J.T.; Dewulf, G.P.M.R.

    2015-01-01

    Purpose – The purpose of this paper is to provide new insights into barriers to sustaining and scaling-up housing and community-care innovations related to changing the long-term care (LTC) system. Design/methodology/approach – Two housing and community-care experiments were studied. The 11 barrie

  18. Geophysical characterization of subsurface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Borns, D.J.

    1995-08-01

    An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier.

  19. Waste Emplacement/Retrieval System Description Document

    Energy Technology Data Exchange (ETDEWEB)

    Eric Loros

    2001-07-25

    The Waste Emplacement/Retrieval System transports Waste Packages (WPs) from the Waste Handling Building (WHB) to the subsurface area of emplacement, and emplaces the WPs once there. The Waste Emplacement/Retrieval System also, if necessary, removes some or all of the WPs from the underground and transports them to the surface. Lastly, the system is designed to remediate abnormal events involving the portions of the system supporting emplacement or retrieval. During emplacement operations, the system operates on the surface between the WHB and North Portal, and in the subsurface in the North Ramp, access mains, and emplacement drifts. During retrieval or abnormal conditions, the operations areas may also extend to a surface retrieval storage site and South Portal on the surface, and the South Ramp in the subsurface. A typical transport and emplacement operation involves the following sequence of events. A WP is loaded into a WP transporter at the WHB, and coupled to a pair of transport locomotives. The locomotives transport the WP from the WHB, down the North Ramp, and to the entrance of an emplacement drift. Once docked at the entrance of the emplacement drift, the WP is moved outside of the WP transporter, and engaged by a WP emplacement gantry. The WP emplacement gantry lifts the WP, and transports it to its emplacement location, where the WP is then lowered to its final resting position. The WP emplacement gantry remains in the drift while the WP transporter is returned to the WHB by the locomotives. When the transporter reaches the WHB, the sequence of operations is repeated. Retrieval of all the WPs, or a large group of WPs, under normal conditions is achieved by reversing the emplacement operations. Retrieval of a small set of WPs, under normal or abnormal conditions, is known as recovery. Recovery performed under abnormal conditions will involve a suite of specialized equipment designed to perform a variety of tasks to enable the recovery process. Recovery

  20. Wave Scattering by Double Slotted Barriers in A Steady Current: Experiments

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The adoption of slotted breakwaters can be an ideal option in the protection of very large near-shore floating structures that may extend offshore to a considerable water depth. In this paper, we experimently investigated the behaviour of wave transmission and reflection coefficients of double slotted barriers in the presence of a steady opposing current. The experimental results show that opposing currents have only minor effects on wave reflection, but can significantly reduce the wave transmission through double slotted barriers. The experimental results suggest that coastal currents should be taken into consideration for an economical design of slotted breakwaters.

  1. Ground Control for Emplacement Drifts for LA

    Energy Technology Data Exchange (ETDEWEB)

    Y. Sun

    2004-07-09

    The purpose of this calculation is to analyze the stability of repository emplacement drifts during the preclosure period, and to provide a final ground support method for emplacement drifts for the License Application (LA). The scope of the work includes determination of input parameter values and loads, selection of appropriate process and methods for the calculation, application of selected methods, such as empirical or analytical, to the calculation, development and execution of numerical models, and evaluation of results. Results from this calculation are limited to use for design of the emplacement drifts and the final ground support system installed in these drifts. The design of non-emplacement openings and their ground support systems is covered in the ''Ground Control for Non-Emplacement Drifts for LA'' (BSC 2004c).

  2. Analysis of emplaced waste data and implications of non-random emplacement for performance assessment for the WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Lawrence E.; Channell, James K.

    2003-05-31

    The WIPP Land Withdrawal Act recognized that after the initial certification of the WIPP and start of disposal operations, operating experience and ongoing research would result in new technical and scientific information. The Environmental Evaluation Group (EEG) has previously reported on issues that it considers important as the Department of Energy (DOE) works towards the first recertification. One of these issues involves the assumption of random emplacement of waste used in the performance assessment calculations in support of the initial certification application. As actual waste emplacement data are now available from four years of disposal, the EEG performed an analysis to evaluate the validity of that initial assumption and determine implications for performance assessment. Panel 1 was closed in March 2003. The degree of deviation between actual emplaced waste in Panel 1 and an assumption of random emplacement is apparent with concentrations of 239Pu being 3.20 times, 240Pu being 2.67 times, and 241Am being 4.13 times the projected repository average for the space occupied by the waste. A spatial statistical analysis was performed using available Panel 1 data retrieved from the WWIS and assigned room coordinates by Sandia National Laboratories. A comparison was made between the waste as emplaced and a randomization of the same waste. Conversely, the distribution of waste as emplaced is similar to the distribution of waste in the individual containers and can be characterized as bi-modal and skewed with a long high-concentration tail. The distribution of randomized waste is fairly symmetrical, as would be expected from classical statistical theory. In the event of a future drilling intrusion, comparison of these two distributions shows a higher probability of intersecting a high-concentration stack of the actual emplaced waste, over that of the same waste emplaced in a randomized manner as was assumed in the certified

  3. Waste Emplacement/Retrieval System Description Document

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-12

    The Waste Emplacement/Retrieval System transports Waste Packages (WPs) from the Waste Handling Building (WHB) to the subsurface area of emplacement, and emplaces the WPs once there. The system also, if necessary, removes some or all of the WPs from the underground and transports them to the surface. Lastly, the system is designed to remediate abnormal events involving the portions of the system supporting emplacement or retrieval. During emplacement operations, the system operates on the surface between the WHB and North Portal, and in the subsurface in the North Ramp, access mains, and emplacement drifts. During retrieval or abnormal conditions, the operations areas may also extend to a surface retrieval storage site and South Portal on the surface, and the South Ramp in the subsurface. A typical transport and emplacement operation involves the following sequence of events. A WP is loaded into a WP transporter at the WHB, and coupled to a pair of transport locomotives. The locomotives transport the WP from the WHB, down the North Ramp, and to the entrance of an emplacement drift. Once docked at the entrance of the emplacment drift, the WP is moved outside of the WP transporter, and engaged by a WP emplacement gantry. The gantry lifts the WP, and transports it to its emplacement location, where the WP is then lowered to its final resting position. The gantry remains in the drift while the WP transporter is returned to the WHB by the locomotives. When the transporter reaches the WHB, the sequence of operations is repeated. Retrieval of all the WPs, or a large group of WPs, under normal conditions is achieved by reversing the emplacement operations. Retrieval of a small set of WPs, under normal or abnormal conditions, is known as recovery. Recovery performed under abnormal conditions will involve a suite of specialized equipment designed to perform a variety of tasks to enable the recovery process. Recovery after abnormal events may require clearing of equipment

  4. Measuring barriers to adherence: validation of the problematic experiences of therapy scale

    OpenAIRE

    2014-01-01

    Purpose: To present the psychometric properties of the Problematic Experiences of Therapy Scale (the PETS), a brief measure to assess self-reported perceived barriers to adherence to physical rehabilitative therapy.\\ud \\ud Methods: Participants (study 1: n?=?128, study 2: n?=?227) taking part in trials of rehabilitative exercises completed the PETS and adherence questions at 12 weeks. Participants in study 2 were also asked about maintained adherence at 6-month follow-up.\\ud \\ud Results: Prin...

  5. A lunar/Martian anchor emplacement system

    Science.gov (United States)

    Clinton, Dustin; Holt, Andrew; Jantz, Erik; Kaufman, Teresa; Martin, James; Weber, Reed

    1993-01-01

    On the Moon or Mars, it is necessary to have an anchor, or a stable, fixed point able to support the forces necessary to rescue a stuck vehicle, act as a stake for a tent in a Martian gale, act as a fulcrum in the erection of general construction poles, or support tent-like regolith shields. The anchor emplacement system must be highly autonomous. It must supply the energy and stability for anchor deployment. The goal of the anchor emplacement system project is to design and build a prototype anchor and to design a conceptual anchor emplacement system. Various anchors were tested in a 1.3 cubic meter test bed containing decomposed granite. A simulated lunar soil was created by adjusting the moisture and compaction characteristics of the soil. We conducted tests on emplacement torque, amount of force the anchor could withstand before failure, anchor pull out force at various angles, and soil disturbances caused by placing the anchor. A single helix auger anchor performed best in this test bed based on energy to emplace, and the ultimate holding capacity. The anchor was optimized for ultimate holding capacity, minimum emplacement torque, and minimum soil disturbance in sandy soils yielding the following dimensions: helix diameter (4.45 cm), pitch (1.27 cm), blade thickness (0.15 cm), total length (35.56 cm), shaft diameter (0.78 cm), and a weight of 212.62 g. The experimental results showed that smaller diameter, single-helix augers held more force than larger diameter augers for a given depth. The emplacement system consists of a flywheel and a motor for power, sealed in a protective box supported by four legs. The flywheel system was chosen over a gear system based on its increased reliability in the lunar environment.

  6. Experiments on the low frequency barrier characteristics of cellular metamaterial panels in a diffuse sound field.

    Science.gov (United States)

    Varanasi, Srinivas; Bolton, J Stuart; Siegmund, Thomas

    2017-01-01

    The metamaterial under investigation here consists of a periodic arrangement of unit plates in a grid-like frame such that there is a contrast in the local areal mass between cell interior and cell wall. In the low frequency range and under normal incidence this metamaterial panel exhibits a sound transmission loss significantly larger than the transmission loss of an unstructured panel with the same homogeneous mass per unit area. However, when the incident sound field is diffuse, the relative advantage of the metamaterial barrier is reduced or eliminated. A sequence of experiments is documented to demonstrate that the relative advantage of the metamaterial barrier can be realized even in a diffuse sound field by creating a hybrid barrier system which embeds the metamaterial layer between a normalizing waveguide layer on the incident side and an absorbing layer on the transmitted side. The sound normalizing waveguide layer is a lattice structure, and the absorbing layer is high performance glass fiber mat. By using measurements of the transmission loss of a 1.2 m square panel system the role of each of these components is demonstrated.

  7. Identity physics experiment on internal transport barriers in JT-60U and JET

    Energy Technology Data Exchange (ETDEWEB)

    De Vries, P C; Beurskens, M N A; Brix, M; Giroud, C; Hawkes, N C; Parail, V [EURATOM/UKAEA Association, Culham Science Centre, OX14 3DB, Abingdon (United Kingdom); Sakamoto, Y; Fujita, T; Hayashi, N; Matsunaga, G; Oyama, N; Shinohara, K; Suzuki, T; Takechi, M [Japan Atomic Energy Agency, Naka, Ibaraki-ken 311-0193 (Japan); Litaudon, X; Joffrin, E [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Crombe, K [Department of Applied Physics, Ghent University, Rozier 44, 9000 Gent (Belgium); Mantica, P [Istituto di Fisica del Plasma, EURATOM/ENEA-CNR Association, Milano (Italy); Salmi, A [Association Euratom-Tekes, Helsinki University of Technology, PO Box 4100 (Finland); Strintzi, D, E-mail: Peter.de.Vries@jet.u [National Technical University of Athens, EURATOM Association, GR-15773, Athens (Greece)

    2009-12-15

    A series of experiments have been carried out in 2008 at JT-60U and JET to find common characteristics and explain differences between internal transport barriers (ITBs). The identity experiments succeeded in matching the profiles of most dimensionless parameters at the time ITBs were triggered. Thereafter the q-profile development deviated due to differences in non-inductive current density profile, affecting the ITB. Furthermore, the ITBs in JET were more strongly influenced by the H-mode pedestal or edge localized modes. It was found to be difficult to match the plasma rotation characteristics in both devices. However, the wide range of Mach numbers obtained in these experiments shows that the rotation has little effect on the triggering of ITBs in plasmas with reversed magnetic shear. On the other hand the toroidal rotation and more specifically the rotational shear had an impact on the subsequent growth and allowed the formation of strong ITBs.

  8. Violence Against Widows in Nepal: Experiences, Coping Behaviors, and Barriers in Seeking Help.

    Science.gov (United States)

    Sabri, Bushra; Sabarwal, Shrutika; Decker, Michele R; Shrestha, Abina; Sharma, Kunda; Thapa, Lily; Surkan, Pamela J

    2016-05-01

    Widows are a vulnerable population in Nepal. This study examined Nepalese widows' experiences of violence, their coping strategies, and barriers faced in seeking help. Study participants were recruited from Women for Human Rights, an NGO in Nepal. A stratified purposive sampling approach was used to select 51 widows and 5 staff members for in-depth interviews. Twenty-seven women who experienced violence were included in this analysis. Data were analyzed and synthesized using a thematic analysis procedure. Widows reported a range of violent experiences perpetrated by family and community members that spanned psychological, physical, and sexual abuse. Women dealt with abusive experiences using both adaptive (e.g., attempting to move ahead, seeking social support, using verbal confrontation) and maladaptive coping strategies (e.g., suicidal thoughts or self-medication). However, they faced barriers to seeking help such as insensitivity of the police, perceived discrimination, and general lack of awareness of widows' problems and needs. Findings highlight the need for interventions across the individual, family, community, and policy levels. Avenues for intervention include creating awareness about widows' issues and addressing cultural beliefs affecting widows' lives. Furthermore, efforts should focus on empowering widows, promoting healthy coping, and addressing their individual needs.

  9. Observations of capillary barriers and preferential flow in layered snow during cold laboratory experiments

    Science.gov (United States)

    Avanzi, Francesco; Hirashima, Hiroyuki; Yamaguchi, Satoru; Katsushima, Takafumi; De Michele, Carlo

    2016-09-01

    Data of liquid water flow around a capillary barrier in snow are still limited. To gain insight into this process, we carried out observations of dyed water infiltration in layered snow at 0 °C during cold laboratory experiments. We considered three different finer-over-coarser textures and three different water input rates. By means of visual inspection, horizontal sectioning, and measurements of liquid water content (LWC), capillary barriers and associated preferential flow were characterized. The flow dynamics of each sample were also simulated solving the Richards equation within the 1-D multi-layer physically based snow cover model SNOWPACK. Results revealed that capillary barriers and preferential flow are relevant processes ruling the speed of water infiltration in stratified snow. Both are marked by a high degree of spatial variability at centimeter scale and complex 3-D patterns. During unsteady percolation of water, observed peaks in bulk volumetric LWC at the interface reached ˜ 33-36 vol % when the upper layer was composed by fine snow (grain size smaller than 0.5 mm). However, LWC might locally be greater due to the observed heterogeneity in the process. Spatial variability in water transmission increases with grain size, whereas we did not observe a systematic dependency on water input rate for samples containing fine snow. The comparison between observed and simulated LWC profiles revealed that the implementation of the Richards equation reproduces the existence of a capillary barrier for all observed cases and yields a good agreement with observed peaks in LWC at the interface between layers.

  10. Ground Control for Emplacement Drifts for SR

    Energy Technology Data Exchange (ETDEWEB)

    Y. Sun

    2000-04-07

    This analysis demonstrates that a satisfactory ground control system can be designed for the Yucca Mountain site, and provides the technical basis for the design of ground support systems to be used in repository emplacement and non-emplacement drifts. The repository ground support design was based on analytical methods using acquired computer codes, and focused on the final support systems. A literature review of case histories, including the lessons learned from the design and construction of the ESF, the studies on the seismic damages of underground openings, and the use of rock mass classification systems in the ground support design, was conducted (Sections 6.3.4 and 6.4). This review provided some basis for determining the inputs and methodologies used in this analysis. Stability of the supported and unsupported emplacement and non-emplacement drifts was evaluated in this analysis. The excavation effects (i.e., state of the stress change due to excavation), thermal effects (i.e., due to heat output from waste packages), and seismic effects (i.e., from potential earthquake events) were evaluated, and stress controlled modes of failure were examined for two in situ stress conditions (k_0=0.3 and 1.0) using rock properties representing rock mass categories of 1 and 5. Variation of rock mass units such as the non-lithophysal (Tptpmn) and lithophysal (Tptpll) was considered in the analysis. The focus was on the non-lithophysal unit because this unit appears to be relatively weaker and has much smaller joint spacing. Therefore, the drift stability and ground support needs were considered to be controlled by the design for this rock unit. The ground support systems for both emplacement and non-emplacement drifts were incorporated into the models to assess their performance under in situ, thermal, and seismic loading conditions. Both continuum and discontinuum modeling approaches were employed in the analyses of the rock mass behavior and in the evaluation of the

  11. Reconceptulizing Language Discordance: Meanings and Experiences of Language Barriers in the U.S. and Taiwan.

    Science.gov (United States)

    Hsieh, Elaine

    2017-02-24

    Individuals with language barriers may face challenges unique to a host society. By examining and comparing the sociocultural conditions that can result in providers and patients not sharing the same language in the United States and in Taiwan, I argue that (a) language discordance is a social phenomenon that may entail diverging meanings and experiences in different countries; (b) language-discordant patients may not share similar experiences even if they are in the same country; and (c) disparities in language concordance may be confounded with other disparities and cultural particulars that are unique to a host society. In addition, because English is a dominant language in medicine, language-discordant patients' quality of care in Taiwan can be moderated by their fluency in English.

  12. Physicians’ experience adopting the electronic transfer of care communication tool: barriers and opportunities

    Directory of Open Access Journals (Sweden)

    de Grood C

    2015-01-01

    Full Text Available Chloe de Grood, Katherine Eso, Maria Jose Santana Department of Community Health Sciences, W21C Research and Innovation Centre, Institute of Public Health, University of Calgary, Calgary, AB, Canada Purpose: The purpose of this study was to assess physicians' perceptions on a newly developed electronic transfer of care (e-TOC communication tool and identify barriers and opportunities toward its adoption. Participants and methods: The study was conducted in a tertiary care teaching center as part of a randomized controlled trial assessing the efficacy of an e-TOC communication tool. The e-TOC technology was developed through iterative consultation with stakeholders. This e-TOC summary was populated by acute care physicians (AcPs and communicated electronically to community care physicians (CcPs. The AcPs consisted of attending physicians, resident trainees, and medical students rotating through the Medical Teaching Unit. The CcPs were health care providers caring for patients discharged from hospital to the community. AcPs and CcPs completed validated surveys assessing their experience with the newly developed e-TOC tool. Free text questions were added to gather general comments from both groups of physicians. Units of analysis were individual physicians. Data from the surveys were analyzed using mixed methods. Results: AcPs completed 138 linked pre- and post-rotation surveys. At post-rotation, each AcP completed an average of six e-TOC summaries, taking an average of 37 minutes per e-TOC summary. Over 100 CcPs assessed the quality of the TOC summaries, with an overall rating of 8.3 (standard deviation: 1.48; on a scale of 1–10. Thematic analyses revealed barriers and opportunities encountered by physicians toward the adoption of the e-TOC tool. While the AcPs highlighted issues with timeliness, usability, and presentation, the CcPs identified barriers accessing the web-based TOC summaries, emphasizing that the summaries were timely and the

  13. The influence of negative ions in helium-oxygen barrier discharges: I. Laser photodetachment experiment

    Science.gov (United States)

    Tschiersch, R.; Nemschokmichal, S.; Meichsner, J.

    2016-04-01

    This work is the experimental part of a comprehensive study that aims to understand the influence of negative ions on the development of atmospheric pressure barrier discharges in electronegative systems. The investigations will be complemented by a 1D numerical fluid simulation. Laser photodetachment experiments were performed in a glow-like barrier discharge operated in helium with admixtures of oxygen up to 1 vol.% at a gas pressure of 500 mbar. The discharge gap between the glass-coated electrodes was 3 mm. The discharge properties were characterized by electrical measurements and optical emission spectroscopy. Laser photodetachment of {{\\text{O}}-} , {\\text{O}}2- , and {\\text{O}}3- was studied using the fundamental and second harmonic wavelength of a Nd-YAG laser. The laser photodetachment of negative ions influences the breakdown characteristics when the laser is fired during the prephase of the discharge only. The breakdown voltage is reduced, which indicates an enhanced pre-ionization initiated by the detached electrons. Systematic variations in the laser pulse in time, the axial laser beam position, the laser pulse energy, and the laser wavelength provided detailed knowledge on this process. The investigation underlines the importance of the discharge prephase in general and aims to differentiate between the negative ion species {{\\text{O}}-} , {\\text{O}}2- , and {\\text{O}}3- .

  14. Longevity of Emplacement Drift Ground Support Materials

    Energy Technology Data Exchange (ETDEWEB)

    Tang, David H.

    2001-05-30

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for the selection of materials for ground support that will function throughout the preclosure period of a potential repository at Yucca Mountain. REV 01 ICN 01 of this analysis is developed in accordance with AP-3.10Q, Analyses and Models, Revision 2, ICN 4, and prepared in accordance with the Technical Work Plan for Subsurface Design Section FY 01 Work Activities (CRWMS M&O 2001a). The objective of this analysis is to update the previous analysis (CRWMS M&O 2000a) to account for related changes in the Ground Control System Description Document (CRWMS M&O 2000b), the Monitored Geologic Repository Project Description Document, which is included in the Requirements and Criteria for Implementing a Repository Design that can be Operated Over a Range of Thermal Modes (BSC 2001), input information, and in environmental conditions, and to provide updated information on candidate ground support materials. Candidate materials for ground support are carbon steel and cement grout. Steel is mainly used for steel sets, lagging, channel, rock bolts, and wire mesh. Cement grout is only considered in the case of grouted rock bolts. Candidate materials for the emplacement drift invert are carbon steel and granular natural material. Materials are evaluated for the repository emplacement drift environment based on the updated thermal loading condition and waste package design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground support materials for use in emplacement drifts. (2) Review existing documents concerning the behavior of candidate ground support materials during the preclosure period. (3) Evaluate impacts of temperature and radiation effects on mechanical and thermal properties of steel. Assess corrosion potential of steel at emplacement drift environment. (4) Evaluate factors

  15. CO2 Dissociation using the Versatile Atmospheric Dielectric Barrier Discharge Experiment (VADER

    Directory of Open Access Journals (Sweden)

    Michael Allen Lindon

    2014-09-01

    Full Text Available Dissociation of CO2 is investigated in an atmospheric pressure dielectric barrier discharge (DBD with a simple, zero dimensional (0-D chemical model and through experiment. The model predicts that the primary CO2 dissociation pathway within a DBD is electron impact dissociation and electron-vibrational excitation. The relaxation kinetics following dissociation are dominated by atomic oxygen chemistry. The experiments included investigating the energy efficiencies and dissociation rates of CO2 within a planar DBD, while the gas flow rate, voltage, gas composition, driving frequency, catalyst, and pulse modes were varied. Some of the VADER results include a maximum CO2 dissociation energy efficiency of 2.5 +/- 0.5%, a maximum CO$_2$ dissociation rate of 4 +/- 0.4*10^-6 mol CO2/s (5 +/- 0.5% percent dissociation, discovering that a resonant driving frequency of ~30 kHz, dependent on both applied voltage and breakdown voltage, is best for efficient CO2 dissociation and that TiO2, a photocatalyst, improved dissociation efficiencies by an average of 18% at driving frequencies above 5 kHz.

  16. Cryovolcanic Emplacement of Domes on Europa

    Science.gov (United States)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Stephen M.

    2016-01-01

    Here we explore the hypothesis that certain domes on Europa may have been produced by the extrusion of viscous cryolavas. A new mathematical method for the emplacement and relaxation of viscous lava domes is presented and applied to putative cryovolcanic domes on Europa. A similarity solution approach is applied to the governing equation for fluid flow in a cylindrical geometry, and dome relaxation is explored assuming a volume of cryolava has been rapidly emplaced onto the surface. Nonphysical sin- gularities inherent in previous models for dome relaxation have been eliminated, and cryolava cooling is represented by a time-variable viscosity. We find that at the onset of relaxation, bulk kinematic viscosities may lie in the range between 10(exp 3) and 10(exp 6) sq m/s, while the actual fluid lava viscosity may be much lower. Plausible relaxation times to form the domes, which are linked to bulk cryolava rheology, are found to range from 3.6 days to 7.5 years. We find that cooling of the cryolava, while dominated by conduction through an icy skin, should not prevent fluids from advancing and relaxing to form domes within the timescales considered. Determining the range of emplacement conditions for putative cryolava domes will shed light on Europa's resurfacing history. In addition, the rheologies and compositions of erupted cryolavas have implications for subsurface cryomagma ascent and local surface stress conditions on Europa.

  17. Longevity of Emplacement Drift Ground Support Materials

    Energy Technology Data Exchange (ETDEWEB)

    D. Tang

    2000-01-07

    The purpose of this analysis is to evaluate the factors affecting the longevity of emplacement drift ground support materials and to develop a basis for selection of materials for ground support that will function throughout the preclosure period. The Development Plan (DP) for this analysis is given in CRWMS M&O (Civilian Radioactive Waste Management System Management and Operating Contractor) (1999a). The candidate materials for ground support are steel (carbon steel, ductile cast iron, galvanized steel, and stainless steel, etc.) and cement. Steel will mainly be used for steel sets, lagging, channels, rock bolts, and wire mesh. Cement usage is only considered in the case of grouted rock bolts. The candidate materials for the invert structure are steel and crushed rock ballast. The materials shall be evaluated for the repository emplacement drift environment under a specific thermal loading condition based on the proposed License Application Design Selection (LADS) design. The analysis consists of the following tasks: (1) Identify factors affecting the longevity of ground control materials for use in emplacement drifts. (2) Review existing documents concerning behavior of candidate ground control materials during the preclosure period. The major criteria to be considered for steel are mechanical and thermal properties, and durability, of which corrosion is the most important concern. (3) Evaluate the available results and develop recommendations for material(s) to be used.

  18. The barriers to nurturing and empowering long-term care experiments - lessons learnt to advance future healthcare projects

    NARCIS (Netherlands)

    Cramer, Hendrik; Dewulf, Geert; Voordijk, Hans

    2014-01-01

    The objective of this study is to explore the barriers to nurturing and empowering subsidized long-term care experiments that try to deal with today's long-term care challenges such as an aging population and increasing healthcare costs. Nurturing is the process of planning, implementing, and learni

  19. Internal electron transport barrier due to neoclassical ambipolarity in the Helically Symmetric Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Lore, J. [University of Wisconsin, Madison; Guttenfelder, Walter [University of Warwick, UK; Briesemeister, Alexis [HSX Laboratory, University of Wisconsin-Madison; Anderson, David [HSX Laboratory, University of Wisconsin-Madison; Anderson, F. S.B. [University of Wisconsin, Madison; Deng, C. B. [University of California; Likin, K. [University of Wisconsin, Madison; Spong, Donald A [ORNL; Talmadge, Joseph [HSX Laboratory, University of Wisconsin-Madison; Zhai, Kan [HSX Laboratory, University of Wisconsin-Madison

    2010-01-01

    Electron cyclotron heated plasmas in the Helically Symmetric Experiment (HSX) feature strongly peaked electron temperature profiles; central temperatures are 2.5 keV with 100 kW injected power. These measurements, coupled with neoclassical predictions of large 'electron root' radial electric fields with strong radial shear, are evidence of a neoclassically driven thermal transport barrier. Neoclassical transport quantities are calculated using the PENTA code [D. A. Spong, Phys. Plasmas 12, 056114 (2005)], in which momentum is conserved and parallel flow is included. Unlike a conventional stellarator, which exhibits strong flow damping in all directions on a flux surface, quasisymmetric stellarators are free to rotate in the direction of symmetry, and the effect of momentum conservation in neoclassical calculations may therefore be significant. Momentum conservation is shown to modify the neoclassical ion flux and ambipolar ion root radial electric fields in the quasisymmetric configuration. The effect is much smaller in a HSX configuration where the symmetry is spoiled. In addition to neoclassical transport, a model of trapped electron mode turbulence is used to calculate the turbulent-driven electron thermal diffusivity. Turbulent transport quenching due to the neoclassically predicted radial electric field profile is needed in predictive transport simulations to reproduce the peaking of the measured electron temperature profile [Guttenfelder et al., Phys. Rev. Lett. 101, 215002 (2008)].

  20. LEARNING CURVES OF LAPAROSCOPY – BARRIERS TO ADOPTION: A MNJIO EXPERIENCE!

    Directory of Open Access Journals (Sweden)

    Ramesh Maturi

    2016-06-01

    Full Text Available BACKGROUND Laparoscopy has been a new entry in the field of surgery with an active history of around just two decades. Today, it is in a position to challenge the conventional surgery which is in use since ages. It is making rapid inroads into various disciplines of surgery. Rapid improvements in optics, along with improvements in energy devices and mechanical stapling devices gave a fillip to acceptance of laparoscopy by the majority of surgeons. Also accumulating data and evidence has started influencing the sceptical, mobilising them to jump into the bandwagon. Barriers to adoption of new techniques, resistance to learning are common to human nature and it is necessary to have a systematic overview of the issues that might crop, so as to be prepared to overcome the problems of accepting laparoscopy into established centres of surgery. AIMS This publication is a reflection of our experience, our trials and tribulations in taking forward the laparoscopy program at our institution. This publication will give an overview of the steps involved in initiation of laparoscopy and aspires to be a source of answers, for day-to-day issues that crop during the process of learning laparoscopy. METHODS AND MATERIALS Just the way, executing laparoscopic surgery is a team effort, incorporating laparoscopy program in an institution is also a team effort where the members of team extend beyond the operating room. Involvement and co-operation of individuals across departments is a must along with benevolent seniors and a proactive administration. So we collated data by interviewing all the stakeholders of laparoscopy program, analysed observations of the faculty from the operating room and reviewed literature on the world wide web. Opinions of the administrators about their perceptions and the issues faced by the junior staff of the department were taken into consideration. Patients were interviewed before and after laparoscopic surgery. CONCLUSIONS Success at

  1. Emplacement Scenarios for Volcanic Domes on Venus

    Science.gov (United States)

    Glaze, Lori S.; Baloga, Steve M.; Stofan, Ellen R.

    2012-01-01

    One key to understanding the history of resurfacing on Venus is better constraints on the emplacement timescales for the range of volcanic features visible on the surface. A figure shows a Magellan radar image and topography for a putative lava dome on Venus. 175 such domes have been identified with diameters ranging from 19 - 94 km, and estimated thicknesses as great as 4 km. These domes are thought to be volcanic in origin and to have formed by the flow of viscous fluid (i.e., lava) on the surface.

  2. Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, J. L. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Bell, R.; Guttenfelder, W.; Hammett, G. W.; Kaye, S. M.; LeBlanc, B.; Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States); Smith, D. R. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Yuh, H. Y. [Nova Photonics Inc., Princeton, New Jersey 08540 (United States)

    2012-05-15

    The National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)] can achieve high electron plasma confinement regimes that are super-critically unstable to the electron temperature gradient driven (ETG) instability. These plasmas, dubbed electron internal transport barriers (e-ITBs), occur when the magnetic shear becomes strongly negative. Using the gyrokinetic code GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)], the first nonlinear ETG simulations of NSTX e-ITB plasmas reinforce this observation. Local simulations identify a strongly upshifted nonlinear critical gradient for thermal transport that depends on magnetic shear. Global simulations show e-ITB formation can occur when the magnetic shear becomes strongly negative. While the ETG-driven thermal flux at the outer edge of the barrier is large enough to be experimentally relevant, the turbulence cannot propagate past the barrier into the plasma interior.

  3. HRE-Pond Cryogenic Barrier Technology Demonstration: Pre- and Post-Barrier Hydrologic Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Moline, G.R.

    1999-06-01

    The Homogeneous Reactor Experiment (HRE) Pond is the site of a former impoundment for radioactive wastes on the Oak Ridge Reservation (ORR) in east Tennessee. The pond received radioactive wastes from 1957 to 1962, and was subsequently drained, filled with soil, and covered with an asphalt cap. The site is bordered to the east and south by an unnamed stream that contains significant concentrations of radioactive contaminants, primarily {sup 90}Sr. Because of the proximity of the stream to the HRE disposal site and the probable flow of groundwater from the site to the stream, it was hypothesized that the HRE Pond has been a source of contamination to the creek. The HRE-Pond was chosen as the site of a cryogenic barrier demonstration to evaluate this technology as a means for rapid, temporary isolation of contaminants in the type of subsurface environment that exists on the ORR. The cryogenic barrier is created by the circulation of liquid CO{sub 2} through a system of thermoprobes installed in boreholes which are backfilled with sand. The probes cool the subsurface, creating a vertical ice wall by freezing adjacent groundwater, effectively surrounding the pond on four sides. The purpose of this investigation was to evaluate the hydrologic conditions within and around the pond prior to, during, and after the cryogenic barrier emplacement. The objectives were (1) to provide a hydrologic baseline for post-banner performance assessment, (2) to confirm that the pond is hydraulically connected to the surrounding sediments, (3) to determine the likely contaminant exit pathways from the pond, and (4) to measure changes in hydrologic conditions after barrier emplacement in order to assess the barrier performance. Because relatively little information about the subsurface hydrology and the actual configuration of the pond existed, data from multiple sources was required to reconstruct this complex system.

  4. LABAN emplacement pipe load-release test and stemming/canister alignment study

    Energy Technology Data Exchange (ETDEWEB)

    Howard, D.L.

    1983-12-02

    An Emplacement Pipe Load-Release Test and a study of downhole alignment during stemming were performed on the LABAN event. The purpose of these experiments was to determine canister and line of sight (LOS) distortion induced by downhole stemming and load-release procedures. The load-release test was aborted at approximately 40% completion due to excessive canister distortions. This report summarizes test results in terms of emplacement pipe loads vs vertical canister motions, canister and LOS lateral displacements, and the changes in LOS alignment that resulted from the downhole stemming and load-release processes.

  5. Magma deformation and emplacement in rhyolitic dykes

    Science.gov (United States)

    McGowan, Ellen; Tuffen, Hugh; James, Mike; Wynn, Peter

    2016-04-01

    Silicic eruption mechanisms are determined by the rheological and degassing behaviour of highly-viscous magma ascending within shallow dykes and conduits. However, we have little knowledge of how magmatic behaviour shifts during eruptions as dykes and conduits evolve. To address this we have analysed the micro- to macro-scale textures in shallow, dissected rhyolitic dykes at the Tertiary Húsafell central volcano in west Iceland. Dyke intrusion at ~3 Ma was associated with the emplacement of subaerial rhyolitic pyroclastic deposits following caldera formation[1]. The dykes are dissected to ~500 m depth, 2-3 m wide, and crop out in two stream valleys with 5-30 m-long exposures. Dykes intrude diverse country rock types, including a welded ignimbrite, basaltic lavas, and glacial conglomerate. Each of the six studied dykes is broadly similar, exhibiting obsidian margins and microcrystalline cores. Dykes within pre-fractured lava are surrounded by external tuffisite vein networks, which are absent from dykes within conglomerate, whereas dykes failed to penetrate the ignimbrite. Obsidian at dyke margins comprises layers of discrete colour. These display dramatic thickness variations and collapsed bubble structures, and are locally separated by zones of welded, brecciated and flow-banded obsidian. We use textural associations to present a detailed model of dyke emplacement and evolution. Dykes initially propagated with the passage of fragmented, gas-charged magma and generation of external tuffisite veins, whose distribution was strongly influenced by pre-existing fractures in the country rock. External tuffisites retained permeability throughout dyke emplacement due to their high lithic content. The geochemically homogenous dykes then evolved via incremental magma emplacement, with shear deformation localised along emplacement boundary layers. Shear zones migrated between different boundary layers, and bubble deformation promoted magma mobility. Brittle

  6. Deep Borehole Emplacement Mode Hazard Analysis Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Sevougian, S. David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-07

    This letter report outlines a methodology and provides resource information for the Deep Borehole Emplacement Mode Hazard Analysis (DBEMHA). The main purpose is identify the accident hazards and accident event sequences associated with the two emplacement mode options (wireline or drillstring), to outline a methodology for computing accident probabilities and frequencies, and to point to available databases on the nature and frequency of accidents typically associated with standard borehole drilling and nuclear handling operations. Risk mitigation and prevention measures, which have been incorporated into the two emplacement designs (see Cochran and Hardin 2015), are also discussed. A key intent of this report is to provide background information to brief subject matter experts involved in the Emplacement Mode Design Study. [Note: Revision 0 of this report is concentrated more on the wireline emplacement mode. It is expected that Revision 1 will contain further development of the preliminary fault and event trees for the drill string emplacement mode.

  7. Study on knowledge, experiences and barriers to mammography among working women from Delhi

    Directory of Open Access Journals (Sweden)

    A Khokhar

    2015-01-01

    Full Text Available INTRODUCTION: Mammography is not a popular screening tool for deducting breast cancer in India although regular screening is associated with reduced mortality from breast cancer. OBJECTIVE: The objective of this study is to find out knowledge, experiences and barriers to mammography among working women of Delhi. MATERIALS AND METHODS: Cross-sectional descriptive study was conducted from October 2012 to March 2013 among working women from Delhi, India. The study was conducted as a part of ongoing training workshops organized for women on early detection of breast cancer. Total of eight such programs were organized and were attended by a total of 439 women. Each participant got a self-administered questionnaire to fill. Data was entered in Microsoft Excel and analysis was done using Statistical product and service solutions (SPSS version 21 (IBM. RESULTS: A total of 439 participants were included in the study. 230 (52.4% of the women were more than 40 years of age. Only four participants (1% had not heard about the term mammography before. Less than half (45.1% of the participants knew correctly the purpose of a mammogram. Only 11.8% of the women knew correctly about the age of getting the first baseline mammogram. Knowledge of frequency of getting the mammogram was also low only 95 (21.6% correctly knew about it. Only 59 (11.9% correctly responded that one needs to go to an imaging facility located either in a hospital or elsewhere to get mammogram done. Main experience shared by the women regarding mammography was that 42 (95.45% did not know anything about the procedure when they went for this investigation. Out of a total of 230 women over 40 years of age only 38 (16.5% had ever got a mammogram carried out. There is a statistically significant association between education status and practice of mammography (P < 0.05. There were 18 women with family history of breast cancer out, of which 10 (55.5% had got mammography carried out. 192 out of

  8. Concept of Operation for Waste Transport, Emplacement, and Retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Norman T. Raczka

    2001-07-02

    The preparation of this technical report has two objectives. The first objective is to discuss the base case concepts of waste transport, emplacement, and retrieval operations and evaluate these operations relative to a lower-temperature repository design. Aspects of the operations involved in waste transport, emplacement and retrieval may be affected by the lower-temperature operating schemes. This report evaluates the effects the lower-temperature alternatives may have on the operational concepts involved in emplacing and retrieving waste. The second objective is to provide backup material for the design description, in a traceable and defensible format, for Section 2 of the Waste Emplacement/Retrieval System Description Document.

  9. Fe-SAPONITE and Chlorite Growth on Stainless Steel in Hydrothermal Engineered Barrier Experiments

    Science.gov (United States)

    Cheshire, M. C.; Caporuscio, F. A.; McCarney, M.

    2012-12-01

    The United States recently has initiated the Used Fuel Disposition campaign to evaluate various generic geological repositories for the disposal of high-level, spent nuclear fuel within environments ranging from hard-rock, salt/clay, to deep borehole settings. Previous work describing Engineered Barrier Systems (EBS) for repositories focused on low temperature and pressure conditions. The focus of this experimental work is to characterize the stability and alteration of a bentonite-based EBS with different waste container materials in brine at higher heat loads and pressures. All experiments were run at ~150 bar and 125 to 300 C for ~1 month. Unprocessed bentonite from Colony, Wyoming was used in the experiments as the clay buffer material. The redox conditions for each system were buffered along the magnetite-iron oxygen fugacity univariant curve using Fe3O4 and Feo filings. A K-Na-Ca-Cl-based salt solution was chosen to replicate deep groundwater compositions. The experimental mixtures were 1) salt solution-clay; 2) salt solution -clay-304 stainless steel; and 3) salt solution -clay-316 stainless steel with a water/bentonite ratio of ~9. Mineralogy and aqueous geochemistry of each experiment was evaluated to monitor the reactions that took place. No smectite illitization was observed in these reactions. However, it appears that K-smectite was produced, possibly providing a precursor to illitization. It is unclear whether reaction times were sufficient for bentonite illitization at 212 and 300 C or whether conditions conducive to illite formation were obtained. The more notable clay mineral reactions occurred at the stainless steel surfaces. Authigenic chlorite and Fe-saponite grew with their basal planes near perpendicular to the steel plate, forming a 10 - 40 μm thick 'corrosion' layer. Partial dissolution of the steel plates was the likely iron source for chlorite/saponite formation; however, dissolution of the Feo/Fe3O4 may also have acted as an iron source

  10. What are the main barriers to healthy eating among families? A qualitative exploration of perceptions and experiences of Tehranian men.

    Science.gov (United States)

    Farahmand, Maryam; Amiri, Parisa; Ramezani Tehrani, Fahimeh; Momenan, Amir Abbas; Mirmiran, Parvin; Azizi, Fereidoun

    2015-06-01

    Despite women playing a pivotal role in shaping nutritional patterns in their families, it is the men whose ideas and preferences, after children, influence the selection and consumption of daily foods among Iranian families. This study focused on exploring the main barriers to healthy eating as experienced by male participants of the Tehran Lipid Glucose Study (TLGS). A grounded theory approach was used for analyzing participants' experiences and their perceptions regarding these barriers. Participants were 98 men, aged 25-65 years, selected and recruited from the TGLS cohort. Data collection was conducted through fourteen semi-structured focus group discussions, between 2008 and 2009. All interviews and focus group discussions were audio recorded and transcribed verbatim. Constant comparative analysis of the data was conducted manually according to the Strauss and Corbin analysis method. The most important barriers to healthy eating were: (i) Personal factors, which included two subthemes--lack of knowledge and personal taste, (ii) Communication and modeling included two subthemes--other individuals and media/advertisements; (iii) Modernization included two subthemes--nutrition transition and women's role; and (iv) Lack of access to healthy foods, which included four subthemes--Inadequate confidence, perceived risk, high cost and time limitations. Appropriate attention and prioritized policy-making to modify the socio-environmental barriers to healthy eating were explored in the current study, along with effective educational programs that could help to promote healthy eating among Iranian families.

  11. Opportunities or Barriers? The Experiences of Disadvantaged Older Jobseekers Participating in Training

    Science.gov (United States)

    Meyers, Rebecca

    2016-01-01

    In Australia and other OECD countries, increasing the labour force participation rate of older adults (45-64 years) is seen as a primary strategy to address the current demographic challenges brought about by an ageing population and the retirement of skilled workers. Not all older adults have current workplace skills, yet barriers which include…

  12. Migrant Sexual Health Help-Seeking and Experiences of Stigmatization and Discrimination in Perth, Western Australia: Exploring Barriers and Enablers.

    Science.gov (United States)

    Agu, Josephine; Lobo, Roanna; Crawford, Gemma; Chigwada, Bethwyn

    2016-05-11

    Increasing HIV notifications amongst migrant and mobile populations to Australia is a significant public health issue. Generalizations about migrant health needs and delayed or deterred help-seeking behaviors can result from disregarding the variation between and within cultures including factors, such as drivers for migration and country of birth. This study explored barriers and enablers to accessing sexual health services, including experiences of stigma and discrimination, within a purposive sample of sub-Saharan African, Southeast Asian, and East Asian migrants. A qualitative design was employed using key informant interviews and focus group discussions. A total of 45 people with ages ranging from 18 to 50 years, participated in focus group discussions. Common barriers and enablers to help seeking behaviors were sociocultural and religious influence, financial constraints, and knowledge dissemination to reduce stigma. Additionally, common experiences of stigma and discrimination were related to employment and the social and self-isolation of people living with HIV. Overcoming barriers to accessing sexual health services, imparting sexual health knowledge, recognizing variations within cultures, and a reduction in stigma and discrimination will simultaneously accelerate help-seeking and result in better sexual health outcomes in migrant populations.

  13. Ground Control for Non-Emplacement Drifts for LA

    Energy Technology Data Exchange (ETDEWEB)

    D. Tang

    2004-02-26

    The purpose of this calculation is to analyze the stability of repository non-emplacement drifts during the preclosure period, and to provide a final ground support method for non-emplacement drifts for the License Application (LA). This calculation will provide input for the development of LA documents. The scope of this calculation is limited to the non-emplacement drifts including access mains, ramps, exhaust mains, turnouts, intersections between access mains and turnouts, and intersections between exhaust mains and emplacement drifts, portals, TBM launch chambers, observation drift and test alcove in the performance confirmation (PC) facilities, etc. The calculation is limited to the non-emplacement drifts subjected to a combined loading of in-situ stress, seismic stress, and/or thermal stress. Other effects such as hydrological and chemical effects are not considered in this analysis.

  14. The Lattice and Thermal Radiation Conductivity of Thermal Barrier Coatings: Models and Experiments

    Science.gov (United States)

    Zhu, Dongming; Spuckler, Charles M.

    2010-01-01

    The lattice and radiation conductivity of ZrO2-Y2O3 thermal barrier coatings was evaluated using a laser heat flux approach. A diffusion model has been established to correlate the coating apparent thermal conductivity to the lattice and radiation conductivity. The radiation conductivity component can be expressed as a function of temperature, coating material scattering, and absorption properties. High temperature scattering and absorption of the coating systems can be also derived based on the testing results using the modeling approach. A comparison has been made for the gray and nongray coating models in the plasma-sprayed thermal barrier coatings. The model prediction is found to have a good agreement with experimental observations.

  15. Relating rock avalanche morphology to emplacement processes

    Science.gov (United States)

    Dufresne, Anja; Prager, Christoph; Bösmeier, Annette

    2015-04-01

    The morphology, structure and sedimentological characteristics of rock avalanche deposits reflect both internal emplacement processes and external influences, such as runout path characteristics. The latter is mainly predisposed by topography, substrate types, and hydrogeological conditions. Additionally, the geological setting at the source slope controls, e.g. the spatial distribution of accumulated lithologies and hence material property-related changes in morphology, or the maximum clast size and amount of fines of different lithological units. The Holocene Tschirgant rock avalanche (Tyrol, Austria) resulted from failure of an intensely deformed carbonate rock mass on the southeast face of a 2,370-m-high mountain ridge. The initially sliding rock mass rapidly fragmented as it moved towards the floor of the Inn River valley. Part of the 200-250 x 106 m3 (Patzelt 2012) rock avalanche debris collided with and moved around an opposing bedrock ridge and flowed into the Ötz valley, reaching up to 6.3 km from source. Where the Tschirgant rock avalanche spread freely it formed longitudinal ridges aligned along motion direction as well as smaller hummocks. Encountering high topography, it left runup ridges, fallback patterns (i.e. secondary collapse), and compressional morphology (successively elevated, transverse ridges). Further evidence for the mechanical landslide behaviour is given by large volumes of mobilized valley-fill sediments (polymict gravels and sands). These sediments indicate both shearing and compressional faulting within the rock avalanche mass (forming their own morphological units through, e.g. in situ bulldozing or as distinctly different hummocky terrain), but also indicate extension of the spreading landslide mass (i.e. intercalated/injected gravels encountered mainly in morphological depressions between hummocks). Further influences on its morphology are given by the different lithological units. E.g. the transition from massive dolomite

  16. Barriers and facilitators to integrating care: experiences from the English Integrated Care Pilots

    Directory of Open Access Journals (Sweden)

    Tom Ling

    2012-07-01

    Full Text Available Background. In 2008, the English Department of Health appointed 16 'Integrated Care Pilots' which used a range of approaches to provide better integrated care. We report qualitative analyses from a three year multi-method evaluation to identify barriers and facilitators to successful integration of care.  Theory and methods. Data were analysed from transcripts of 213 in-depth staff interviews, and from semi-structured questionnaires (the 'Living Document' completed by staff in pilot sites at six points over a two-year period. Emerging findings were therefore built from 'bottom up' and grounded in the data. However, we were then interested in how these findings compared and contrasted with more generic analyses. Therefore after our analyses were complete we then systematically compared and contrasted the findings with the analysis of barriers and facilitators to quality improvement identified in a systematic review by Kaplan et al (2010 and the analysis of more micro-level shapers of behaviour found in Normalisation Process Theory (May et al 2007. Neither of these approaches claims to be full blown theories but both claim to provide mid-range theoretical arguments which may be used to structure existing data and which can be undercut or reinforced by new data. Results and discussion. Many barriers and facilitators to integrating care are those of any large scale organisational change. These include issues relating to leadership, organisational culture, information technology, physician involvement, and availability of resources. However, activities which appear particularly important for delivering integrated care include personal relationships between leaders in different organisations, the scale of planned activities, governance and finance arrangements, support for staff in new roles, and organisational and staff stability. We illustrate our analyses with a 'routemap' which identifies questions that providers may wish to consider when

  17. Barriers and facilitators to integrating care: experiences from the English Integrated Care Pilots

    Directory of Open Access Journals (Sweden)

    Tom Ling

    2012-07-01

    Full Text Available Background. In 2008, the English Department of Health appointed 16 'Integrated Care Pilots' which used a range of approaches to provide better integrated care. We report qualitative analyses from a three year multi-method evaluation to identify barriers and facilitators to successful integration of care. Theory and methods. Data were analysed from transcripts of 213 in-depth staff interviews, and from semi-structured questionnaires (the 'Living Document' completed by staff in pilot sites at six points over a two-year period. Emerging findings were therefore built from 'bottom up' and grounded in the data. However, we were then interested in how these findings compared and contrasted with more generic analyses. Therefore after our analyses were complete we then systematically compared and contrasted the findings with the analysis of barriers and facilitators to quality improvement identified in a systematic review by Kaplan et al (2010 and the analysis of more micro-level shapers of behaviour found in Normalisation Process Theory (May et al 2007. Neither of these approaches claims to be full blown theories but both claim to provide mid-range theoretical arguments which may be used to structure existing data and which can be undercut or reinforced by new data.Results and discussion. Many barriers and facilitators to integrating care are those of any large scale organisational change. These include issues relating to leadership, organisational culture, information technology, physician involvement, and availability of resources. However, activities which appear particularly important for delivering integrated care include personal relationships between leaders in different organisations, the scale of planned activities, governance and finance arrangements, support for staff in new roles, and organisational and staff stability. We illustrate our analyses with a 'routemap' which identifies questions that providers may wish to consider when planning

  18. Possibilities and Barriers for Energy Conservation in a Liberalised Electricity Market: Danish Utility Experiences

    DEFF Research Database (Denmark)

    Meyer, Niels I

    1999-01-01

    Liberalisation of energy markets in Europe is in progress. The expressed goal is to promote efficiency through commercial competition, with lower energy prices for consumers as a consequence. This priority raises some complex questions in relation to the desire of creating a sustainable energy...... development.Commercial competition has a short time horizon and a goal function of profit maximizing. In contrast to this, creation of a sustainable development requires long time horizons and comprehensive societal planning and regulation.This paper analyses the possibilities and barriers for promoting...

  19. [Overcoming language barriers with telephone interpreters: first experiences at a German children's hospital].

    Science.gov (United States)

    Langer, Thorsten; Wirth, Stefan

    2014-01-01

    Language barriers in the care for patients with limited German language proficiency contribute to impaired quality of care, more frequent medical errors and decreased patient satisfaction. However, professional interpreters are not systematically used in Germany. We conducted a pilot study in a German paediatric hospital to explore the demand for an interpreter by conducting a survey among parents and to test the use of telephone interpreters. Eight percent of the respondents said they were interested in interpreter support. All physicians and parents using a telephone interpreter were very satisfied with the quality and the organisation of the service.

  20. Topographic and Stochastic Influences on Pahoehoe Lava Lobe Emplacement

    Science.gov (United States)

    Hamilton, Christopher W.; Glaze, Lori S.; James, Mike R.; Baloga, Stephen M.

    2013-01-01

    A detailed understanding of pahoehoe emplacement is necessary for developing accurate models of flow field development, assessing hazards, and interpreting the significance of lava morphology on Earth and other planetary surfaces. Active pahoehoe lobes on Kilauea Volcano, Hawaii, were examined on 21-26 February 2006 using oblique time-series stereo-photogrammetry and differential global positioning system (DGPS) measurements. During this time, the local discharge rate for peripheral lava lobes was generally constant at 0.0061 +/- 0.0019 m3/s, but the areal coverage rate of the lobes exhibited a periodic increase every 4.13 +/- 0.64 minutes. This periodicity is attributed to the time required for the pressure within the liquid lava core to exceed the cooling induced strength of its margins. The pahoehoe flow advanced through a series of down slope and cross-slope breakouts, which began as approximately 0.2 m-thick units (i.e., toes) that coalesced and inflated to become approximately meter-thick lobes. The lobes were thickest above the lowest points of the initial topography and above shallow to reverse facing slopes, defined relative to the local flow direction. The flow path was typically controlled by high-standing topography, with the zone directly adjacent to the final lobe margin having an average relief that was a few centimeters higher than the lava inundated region. This suggests that toe-scale topography can, at least temporarily, exert strong controls on pahoehoe flow paths by impeding the lateral spreading of the lobe. Observed cycles of enhanced areal spreading and inflated lobe morphology are also explored using a model that considers the statistical likelihood of sequential breakouts from active flow margins and the effects of topographic barriers.

  1. Barriers to live donor kidney transplants in the pediatric population: A single-center experience.

    Science.gov (United States)

    Taormina, Shibany P; Galloway, Matthew P; Jain, Amrish

    2017-03-01

    A decrease in live donor pediatric kidney transplants has occurred in the United States. This study investigates barriers that may influence access to live donor kidney transplants in children. Retrospective chart review was conducted for 91 children (69% male, mean age 11.9 years) who underwent pretransplant workup from 2005 to 2015 at an urban pediatric hospital. Fifty-four percent were African American, 32% Caucasian, 8% Arabic, 3% Hispanic, and 3% Others. Government-sponsored insurance (Medicaid/Medicare) was utilized by 73%, and 54% had dual caregivers. Only nine of 68 kidney transplants were live donor transplants. Live donor transplants (11%) were significantly (P=.008) lower than deceased donor transplants (59%) in African Americans. Private insurance was reported by 56% of live donor recipients and 25% of deceased donor recipients. Among live donor recipients, 78% were from dual caregiver families. Caregiver, health-related, financial, and religious/cultural barriers to live donor transplants were reported, several of which may be amenable to positive intervention.

  2. Nornahraun lava morphology and mode of emplacement

    Science.gov (United States)

    Pedersen, Gro B. M.; Höskuldsson, Armann; Riishuus, Morten S.; Jónsdóttir, Ingibjörg; Gudmundsson, Magnús T.; Sigmundsson, Freysteinn; Óskarsson, Birgir V.; Drouin, Vincent; Gallagher, Catherine; Askew, Rob; Moreland, William M.; Dürig, Tobias; Dumont, Stephanie; Þórdarson, Þór

    2015-04-01

    The ongoing Nornahraun eruption is the largest effusive eruption in Iceland since the Laki eruption in 1783-84, with an estimated lava volume of ~1.15 km3 covering an area of ~83.4 km2 (as of 5 JAN 2015). The eruption provides an unprecedented opportunity to study i) lava morphologies and their emplacement styles, ii) the transition from from open to closed lava pathways and iii) lava pond formation. Tracking of the lava advancement and morphology has been performed by GPS and GoPro cameras installed in 4×4 vehicles as well as video footage. Complimentary observations have been provided from aircraft platforms and by satellite data. Of particular importance for lava morphology observations are 1-12 m/pixel airborne SAR images (x-band). The Nornahraun flow field comprises a continuum of morphologies from pāhoehoe to 'a'ā, which have varied tem-porally and spatially. At the onset of the eruption 31 AUG, lava flows advanced rapidly (400-800 m/hr) from the 1.5 km long fissure as large slabby pāhoehoe [1-3] sheet lobes, 100-500 m wide and 0.3-1 m thick at the flow fronts. By 1 SEPT, the flows began channeling towards the NE constrained by the older Holuhraun I lava field and the to-pography of flood plain itself. A central open channel developed, feeding a 1-2 km wide active 'a'ā frontal lobe that advanced 1-2 km/day. In addition to its own caterpillar motion, the frontal lobe advanced in a series of 30-50 m long breakouts, predominantly slabby and rubbly pāhoehoe [4,5]. These breakouts had initial velocities of 10-30 m/hr and reached their full length within tens of minutes and subsequently inflated over hours. With the continuous advancement of the 'a'ā flow front, the breakouts were incorporated into the 'a'ā flow fronts and seldom preserved. At the margins of the frontal lava lobe, the breakouts were more sporadic, but predominantly rubbly pāhoehoe and slabby pāhoehoe, as at the flow front. The lava flow advanced ENE into Jökulsá á Fjöllum on 7 SEPT

  3. Rootless tephra stratigraphy and emplacement processes

    Science.gov (United States)

    Hamilton, Christopher W.; Fitch, Erin P.; Fagents, Sarah A.; Thordarson, Thorvaldur

    2017-01-01

    Volcanic rootless cones are the products of thermohydraulic explosions involving rapid heat transfer from active lava (fuel) to external sources of water (coolant). Rootless eruptions are attributed to molten fuel-coolant interactions (MFCIs), but previous studies have not performed systematic investigations of rootless tephrostratigraphy and grain-size distributions to establish a baseline for evaluating relationships between environmental factors, MFCI efficiency, fragmentation, and patterns of tephra dispersal. This study examines a 13.55-m-thick vertical section through an archetypal rootless tephra sequence, which includes a rhythmic succession of 28 bed pairs. Each bed pair is interpreted to be the result of a discrete explosion cycle, with fine-grained basal material emplaced dominantly as tephra fall during an energetic opening phase, followed by the deposition of coarser-grained material mainly as ballistic ejecta during a weaker coda phase. Nine additional layers are interleaved throughout the stratigraphy and are interpreted to be dilute pyroclastic density current (PDC) deposits. Overall, the stratigraphy divides into four units: unit 1 contains the largest number of sediment-rich PDC deposits, units 2 and 3 are dominated by a rhythmic succession of bed pairs, and unit 4 includes welded layers. This pattern is consistent with a general decrease in MFCI efficiency due to the depletion of locally available coolant (i.e., groundwater or wet sediments). Changing conduit/vent geometries, mixing conditions, coolant and melt temperatures, and/or coolant impurities may also have affected MFCI efficiency, but the rhythmic nature of the bed pairs implies a periodic explosion process, which can be explained by temporary increases in the water-to-lava mass ratio during cycles of groundwater recharge.

  4. Kimberlite emplacement temperatures from conodont geothermometry

    Science.gov (United States)

    Pell, Jennifer; Russell, James K.; Zhang, Shunxin

    2015-02-01

    Kimberlites are mantle-derived ultramafic rocks preserved in volcanic and sub-volcanic edifices and are the main primary source of diamonds. The temperatures of formation, transport, eruption and deposition remain poorly constrained despite their importance for understanding the petrological and thermodynamic properties of kimberlite magmas and styles of volcanic eruption. Here, we present measured values of Colour Alteration Indices (CAI) for conodonts recovered from 76 Paleozoic carbonate xenoliths found within 11 pipes from the Chidliak kimberlite field on Baffin Island, Nunavut, Canada. The dataset comprises the largest range of CAI values (1.5 to 8) and the highest CAI values reported to date for kimberlite-hosted xenoliths. Thermal models for cooling of the Chidliak kimberlite pipes and synchronous heating of conodont-bearing xenoliths indicate time windows of 10-20 000 h and, for these short time windows, the measured CAI values indicate heating of the xenoliths to temperatures of 225 to >925 °C. We equate these temperatures with the minimum temperatures of the conduit-filling kimberlite deposit (i.e. emplacement temperature, TE). The majority of the xenoliths record CAI values of between 5 and 6.5 suggesting heating of xenoliths to temperatures of 460 °C-735 °C. The highest CAI values are consistent with being heated to 700 °C-925 °C and establish the minimum conditions for welding or formation of clastogenic kimberlite deposits. Lastly, we use TE variations within and between individual pipes, in conjunction with the geology of the conduit-filling deposits, to constrain the styles of explosive volcanic eruption.

  5. Design of experiment analysis of CO2 dielectric barrier discharge conditions on CO production

    Science.gov (United States)

    Becker, Markus; Ponduri, Srinath; Engeln, Richard; van de Sanden, Richard; Loffhagen, Detlef

    2016-09-01

    Dielectric barrier discharges (DBD) are frequently used for the generation of CO from CO2 which is of particular interest for syngas production. It has been found by means of fluid modelling in that the CO2 conversion frequency in a CO2 DBD depends linearly on the specific energy input (SEI) while the energy efficiency of CO production is only weakly dependent on the SEI. Here, the same numerical model as in is applied to study systematically the influence of gas pressure, applied voltage amplitude and frequency on the CO2 conversion frequency and the energy efficiency of CO production based on a 2-level 3-factor full factorial experimental design. It is found that the operating conditions of the CO2 DBD for CO production can be chosen to either have an optimal throughput or a better energy efficiency. This work was partly supported by the German Research Foundation within the Collaborative Research Centre Transregio 24.

  6. Pre-college experiences in and out of the classroom lead to first-year barriers

    Science.gov (United States)

    Reed, D. E.; Kaplita, E.; McKenzie, D. A.; Jones, R.; May, L. W.

    2015-12-01

    Students often enter college with preconceived notions about science. These misconceptions, coupled with a potential for a limited number of science classes during college for non-science majors, can make correcting misconceptions a very daunting challenge. In order to efficiently commutate climate science in a limited number of science classes, instructors need to understand the student experiences that have created their preconceived notions. In many cases, a lack of data about student's experiences leads to instructors simply guessing at how students are thinking about and interacting with science. Student surveys were used in our work to quantify pre-college experiences, both in and out of the classroom, in order to examine the connection to both academic major and choice of college or university students attended. Surveys were given to nearly 400 students across 4 different schools in the Oklahoma City Metro area. The location of students (rural or urban) affected science experiences as well as what types of actives (local libraries, museums, or parks) were available to the students. Connections between the timing of experience (elementary through high school) and the type of experience (in the classroom, with family/friends, or on their own) may influence choice of college or university as well as academic major. A better understating of positive student science experiences will allow instructors to better tailor their pedagogy and facilitate better connections between climate science and students.

  7. Motivators and barriers to using patient experience reports for performance improvement

    NARCIS (Netherlands)

    Geissler, K.H.; Friedberg, M.W.; SteelFisher, G.K.; Schneider, E.C.

    2013-01-01

    Increasingly, patient experience surveys are available to provide performance feedback to physician groups. However, limited published literature addresses factors influencing use of these reports for performance improvement. To address this gap, we conducted semistructured interviews with leaders o

  8. Barriers to addressing the social determinants of health: insights from the Canadian experience.

    Science.gov (United States)

    Raphael, Dennis; Curry-Stevens, Ann; Bryant, Toba

    2008-12-01

    Despite Canada's reputation as a leader in health promotion and population health, implementation of public policies in support of the social determinants of health has been woefully inadequate. The continuing presence of income, housing, and food insecurity has led to Canada being the subject of a series of rebukes from the United Nations for failing to address child and family poverty, discrimination against women and Aboriginal groups, and most recently the crisis of homelessness and housing insecurity. In this article we consider some of the reasons why this might be the case. These include the epistemological dominance of positivist approaches to the health sciences, the ideology of individualism prevalent in North America, and the increasing influence on public policy of the marketplace. Various models of public policy provide pathways by which these barriers can be surmounted. Considering that the International Commission on the Social Determinants of Health will soon be releasing its findings and recommendations, such an analysis seems especially timely for understanding both the Canadian scene and developments in other nations.

  9. Correlating DFT-calculated energy barriers to experiments in nonheme octahedral Fe(IV)O species.

    Science.gov (United States)

    Cho, Kyung-Bin; Kim, Eun Jeong; Seo, Mi Sook; Shaik, Sason; Nam, Wonwoo

    2012-08-13

    The experimentally measured bimolecular reaction rate constant, k(2), should in principle correlate with the theoretically calculated rate-limiting free energy barrier, ΔG(≠), through the Eyring equation, but it fails quite often to do so due to the inability of current computational methods to account in a precise manner for all the factors contributing to ΔG(≠). This is further aggravated by the exponential sensitivity of the Eyring equation to these factors. We have taken herein a pragmatic approach for C-H activation reactions of 1,4-cyclohexadiene with a variety of octahedral nonheme Fe(IV)O complexes. The approach consists of empirically determining two constants that would aid in predicting experimental k(2) values uniformly from theoretically calculated electronic energy (ΔE(≠)) values. Shown in this study is the predictive power as well as insights into energy relationships in Fe(IV)O C-H activation reactions. We also find that the difference between ΔG(≠) and ΔE(≠) converges at slow reactions, in a manner suggestive of changes in the importance of the triplet spin state weight in the overall reaction.

  10. Thermal Conductivity in Suspension Sprayed Thermal Barrier Coatings: Modeling and Experiments

    Science.gov (United States)

    Ganvir, Ashish; Kumara, Chamara; Gupta, Mohit; Nylen, Per

    2016-12-01

    Axial suspension plasma spraying (ASPS) can generate microstructures with higher porosity and pores in the size range from submicron to nanometer. ASPS thermal barrier coatings (TBC) have already shown a great potential to produce low thermal conductivity coatings for gas turbine applications. It is important to understand the fundamental relationships between microstructural defects in ASPS coatings such as crystallite boundaries, porosity etc. and thermal conductivity. Object-oriented finite element (OOF) analysis has been shown as an effective tool for evaluating thermal conductivity of conventional TBCs as this method is capable of incorporating the inherent microstructure in the model. The objective of this work was to analyze the thermal conductivity of ASPS TBCs using experimental techniques and also to evaluate a procedure where OOF can be used to predict and analyze the thermal conductivity for these coatings. Verification of the model was done by comparing modeling results with the experimental thermal conductivity. The results showed that the varied scaled porosity has a significant influence on the thermal conductivity. Smaller crystallites and higher overall porosity content resulted in lower thermal conductivity. It was shown that OOF could be a powerful tool to predict and rank thermal conductivity of ASPS TBCs.

  11. Thermal Conductivity in Suspension Sprayed Thermal Barrier Coatings: Modeling and Experiments

    Science.gov (United States)

    Ganvir, Ashish; Kumara, Chamara; Gupta, Mohit; Nylen, Per

    2017-01-01

    Axial suspension plasma spraying (ASPS) can generate microstructures with higher porosity and pores in the size range from submicron to nanometer. ASPS thermal barrier coatings (TBC) have already shown a great potential to produce low thermal conductivity coatings for gas turbine applications. It is important to understand the fundamental relationships between microstructural defects in ASPS coatings such as crystallite boundaries, porosity etc. and thermal conductivity. Object-oriented finite element (OOF) analysis has been shown as an effective tool for evaluating thermal conductivity of conventional TBCs as this method is capable of incorporating the inherent microstructure in the model. The objective of this work was to analyze the thermal conductivity of ASPS TBCs using experimental techniques and also to evaluate a procedure where OOF can be used to predict and analyze the thermal conductivity for these coatings. Verification of the model was done by comparing modeling results with the experimental thermal conductivity. The results showed that the varied scaled porosity has a significant influence on the thermal conductivity. Smaller crystallites and higher overall porosity content resulted in lower thermal conductivity. It was shown that OOF could be a powerful tool to predict and rank thermal conductivity of ASPS TBCs.

  12. Emplacement Guidance for Criticality Safety in Low-Level-Waste Disposal

    Energy Technology Data Exchange (ETDEWEB)

    Elam, K.R.

    2001-06-23

    may apply to facilities that emplace somewhat higher areal densities of SNM but do not use vaults or segmentation in the disposal emplacement. The third graded-approach method relies on limiting the average concentration by weight of SNM in the waste, and on the presence of segmenting barriers, such as vaults, which will mitigate interaction between units of SNM. This method may apply to facilities that use concrete vaults in their disposal areas, and allows even higher areal density of SNM in the disposal site.

  13. Oxidation of volatile organic compound vapours by potassium permanganate in a horizontal permeable reactive barrier under unsaturated conditions: experiments and modeling

    NARCIS (Netherlands)

    Ghareh Mahmoodlu, Mojtaba

    2014-01-01

    In this research we evaluated the potential of using solid potassium permanganate to create a horizontal permeable reactive barrier (HPRB) for oxidizing VOC vapours in the unsaturated zone. We have performed batch experiments, short column, and long column experiments, and have fully analyzed the da

  14. Latina/o Food Industry Employees' Work Experiences: Work Barriers, Facilitators, Motivators, Training Preferences, and Perceptions

    Science.gov (United States)

    Kanagui-Munoz, Marlen; Garriott, Patton O.; Flores, Lisa Y.; Cho, Seonghee; Groves, James

    2012-01-01

    The present study explored the work experiences, job satisfaction, and work behaviors of Latina/o restaurant workers. A total of 10 semistructured focus group (N = 75) interviews were conducted in the Midwest and Southwest. Data were analyzed using a combination of Consensual Qualitative Research (CQR; Hill et al., 2005; Hill, Thompson, &…

  15. Qualitative Analysis of the Barriers College Students with Disabilities Experience in Higher Education

    Science.gov (United States)

    Hong, Barbara S. S.

    2015-01-01

    Students with disabilities are increasingly enrolling in colleges and universities. However, many institutions are still unprepared to support them beyond the basic federal mandate of equal access and reasonable accommodations. This qualitative study utilized a nontraditional media of reflective journaling to capture the anecdotal experiences of…

  16. A Survey of Homework Use, Experience of Barriers to Homework, and Attitudes about the Barriers to Homework among Couples and Family Therapists

    Science.gov (United States)

    Dattilio, Frank M.; Kazantzis, Nikolaos; Shinkfield, Gregg; Carr, Amanda G.

    2011-01-01

    Homework is a therapeutic process that has strong theoretical and empirical basis, but existing research has focused on "compliance" rather than considering the broader and more clinically meaningful construct of "engagement." Absent in the literature is empirical study of the barriers to engagement or study of homework use among couple and family…

  17. Attenuation of pyrite oxidation with a fly ash pre-barrier: Reactive transport modelling of column experiments

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Lopez, R.; Cama, J.; Nieto, J.M.; Ayora, C.; Saaltink, M.W. [University of Huelva, Huelva (Spain). Dept. of Geology

    2009-09-15

    Conventional permeable reactive barriers (PRBs) for passive treatment of groundwater contaminated by acid mine drainage (AMD) use limestone as reactive material that neutralizes water acidity. However, the limestone-alkalinity potential ceases as inevitable precipitation of secondary metal-phases on grain surfaces occurs, limiting its efficiency. In the present study, fly ash derived from coal combustion is investigated as an alternative alkalinity generating material for the passive treatment of AMD using solution-saturated column experiments. Unlike conventional systems, the utilization of fly ash in a pre-barrier to intercept the non-polluted recharge water before this water reacts with pyrite-rich wastes is proposed. Chemical variation in the columns was interpreted with the reactive transport code RETRASO. In parallel, kinetics of fly ash dissolution at alkaline pH were studied using flow-through experiments and incorporated into the model. In a saturated column filled solely with pyritic sludge-quartz sand (1: 10), oxidation took place at acidic conditions (pH 3.7). According to SO{sub 4}{sup 2-} release and pH, pyrite dissolution occurred favourably in the solution-saturated porous medium until dissolved O{sub 2} was totally consumed. In a second saturated column, pyrite oxidation took place at alkaline conditions (pH 10.45) as acidity was neutralized by fly ash dissolution in a previous level. At this pH Fe release from pyrite dissolution was immediately depleted as Fe-oxy(hydroxide) phases that precipitated on the pyrite grains, forming Fe-coatings (microencapsulation). With time, pyrite microencapsulation inhibited oxidation in practically 97% of the pyritic sludge. Rapid pyrite-surface passivation decreased its reactivity, preventing AMD production in the relatively short term.

  18. An examination of how women and underrepresented racial/ethnic minorities experience barriers in biomedical research and medical programs

    Science.gov (United States)

    Chakraverty, Devasmita

    Women in medicine and biomedical research often face challenges to their retention, promotion, and advancement to leadership positions (McPhillips et al., 2007); they take longer to advance their careers, tend to serve at less research-intensive institutions and have shorter tenures compared to their male colleagues (White, McDade, Yamagata, & Morahan, 2012). Additionally, Blacks and Hispanics are the two largest minority groups that are vastly underrepresented in medicine and biomedical research in the United States (AAMC, 2012; NSF, 2011). The purpose of this study is to examine specific barriers reported by students and post-degree professionals in the field through the following questions: 1. How do women who are either currently enrolled or graduated from biomedical research or medical programs define and make meaning of gender-roles as academic barriers? 2. How do underrepresented groups in medical schools and biomedical research institutions define and make meaning of the academic barriers they face and the challenges these barriers pose to their success as individuals in the program? These questions were qualitatively analyzed using 146 interviews from Project TrEMUR applying grounded theory. Reported gender-role barriers were explained using the "Condition-Process-Outcome" theoretical framework. About one-third of the females (across all three programs; majority White or Black between 25-35 years of age) reported gender-role barriers, mostly due to poor mentoring, time constraints, set expectations and institutional barriers. Certain barriers act as conditions, causing gender-role issues, and gender-role issues influence certain barriers that act as outcomes. Strategies to overcome barriers included interventions mostly at the institutional level (mentor support, proper specialty selection, selecting academia over medicine). Barrier analysis for the two largest URM groups indicated that, while Blacks most frequently reported racism, gender barriers

  19. Melt production and magma emplacement: What use are they?

    Science.gov (United States)

    Nimmo, F.

    2003-04-01

    I will review the processes of melt production and magma emplacement and address two questions: how do these processes affect planetary evolution?; and what can we learn from observing them, both now and in the future? Melt production is primarily controlled by the temperature of the planetary interior. The extraction of melt from silicate mantles has a number of effects. Firstly, it advects heat (e.g. Io, Venus?). Secondly, it segregates radiogenic materials into the crust, thus cooling the mantle (e.g. Mars, Earth). Thirdly, it removes volatiles from the interior (e.g. Venus, Mars). Recognition that melting is occurring gives us information about likely conditions inside the planet. Models of melt generation by convective upwelling have been used to constrain the interior properties of the Earth, Venus and Mars. Melting during tidal heating (Io) or accretion is less well understood. Magma emplacement is primarily controlled by the density of the magma and the surrounding material. Extrusive activity is likely for high volatile concentrations or low crustal densities. Water is particularly difficult to erupt, since (unlike silicates) the melt is denser than the solid. Different styles of magma emplacement are observed: voluminous surface flows and volcanic edifices of various kinds (ubiquitous); giant radiating dyke swarms (Earth, Venus, Mars); intrusive sills and diapirs (Earth, Venus?, Mars?, Europa?). The extrusive emplacement of magma will cause resurfacing, and is thus easily detected. The release of volatiles during emplacement may have local (e.g. Laki) or global (Venus? Mars?) effects on climate and atmosphere. Intrusive emplacement is harder to detect, but may interact with local volatiles to create unusual landforms (Earth, Mars). The style and volume of emplacement is a useful diagnostic tool. The morphology of lava flows gives information about the rheology and composition of the flow material (e.g. Venus, Miranda). Observations of dykes may be used to

  20. Oxygen isotope evidence for shallow emplacement of Adirondack anorthosite

    Science.gov (United States)

    Valley, J.W.; O'Neil, J.R.

    1982-01-01

    Oxygen isotopic analysis of wollastonites from the Willsboro Mine, Adirondack Mountains, New York reveals a 400-ft wide zone of 18O depletion at anorthosite contacts. Values of ??18O vary more sharply with distance and are lower (to -1.3) than any yet reported for a granulite fades terrain. Exchange with circulating hot meteoric water best explains these results and implies that the anorthosite was emplaced at relatively shallow depths, granulite fades metamorphism (23 km). These 18O depletions offer the first strong evidence for shallow emplacement of anorthosite within the Grenville Province and suggest that regional metamorphism was a later and tectonically distinct event. ?? 1982 Nature Publishing Group.

  1. Colonisation in social species: the importance of breeding experience for dispersal in overcoming information barriers

    Science.gov (United States)

    Payo-Payo, A.; Genovart, M.; Sanz-Aguilar, A.; Greño, J. L.; García-Tarrasón, M.; Bertolero, A.; Piccardo, J.; Oro, D.

    2017-02-01

    Studying colonisation is crucial to understand metapopulations, evolutionary ecology and species resilience to global change. Unfortunately, few empirical data are available because field monitoring that includes empty patches at large spatiotemporal scales is required. We examine the colonisation dynamics of a long-lived seabird over 34 years in the western Mediterranean by comparing population and individual data from both source colony and the newly-formed colonies. Since social information is not available, we hypothesize that colonisation should follow particular dispersal dynamics and personal information must be crucial in decision making. We test if adverse breeding conditions trigger colonisation events, if personal information plays a role in colonisation and if colonisers experience greater fitness. Our results show a temporal mismatch between colonisation events and both density-dependence and perturbations at the source colony, probably because colonisers needed a longer prospecting period to compensate for the lack of public information. Colonisers were mostly experienced individuals gaining higher breeding success in the new colony. Our results highlight the demographic value that experienced individuals can have on metapopulation dynamics of social long-lived organisms.

  2. Final disposal in deep boreholes using multiple geological barriers. Digging deeper for safety. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Bracke, Guido; Hurst, Stephanie; Merkel, Broder; Mueller, Birgit; Schilling, Frank

    2016-03-15

    The proceedings of the workshop on final disposal in deep boreholes using multiple geological barriers - digging deeper for safety include contributions on the following topics: international status and safety requirements; geological and physical barriers; deep drilling - shaft building; technical barriers and emplacement technology for high P/T conditions; recovery (waste retrieval); geochemistry and monitoring.

  3. Determination of the Rotational Barrier for Kinetically Stable Conformational Isomers via NMR and 2D TLC: An Introductory Organic Chemistry Experiment

    Science.gov (United States)

    Rushton, Gregory T.; Burns, William G.; Lavin, Judi M.; Chong, Yong S.; Pellechia, Perry; Shimizu, Ken D.

    2007-01-01

    An experiment to determine the rotational barrier about a C[subscript aryl]-N[subscript imide] single bond that is suitable for first-semester organic chemistry students is presented. The investigation begins with the one-step synthesis of a N,N'-diaryl naphthalene diimide, which exists as two room temperature-stable atropisomers (syn and anti).…

  4. Ejecta emplacement: from distal to proximal

    Science.gov (United States)

    Artemieva, N.

    2008-09-01

    ejected material is about 160 km3 (with an average sediment/basement proportion of 3:1). The maximum ejection velocity for crystalline rocks does not exceed 1 km/s. There are no basement ejecta in the uprange direction. Ejecta deposited within a ring of 16-18 km radius (similar to the position of the Otting site) have a deposition velocity of ~350 m/s. This velocity allows substantial reworking of ejecta and mixing with target rocks. Otting ejecta consist of a sediment /basement rock mixture. The average shock compression of basement rocks is at least 4 times higher than in sediments for any azimuthal angle (16 GPa versus 4 GPa). Ejecta thickness (tens of m) is in a reasonable agreement with observations. However, our modeling results relevant to ballistic deposition do not allow to reproduce the observed ejecta in the suevite layer of Otting: 1) there is just very little melt in the modeled ejecta and 2) separation of sedimentary rocks from basement rocks (i.e. Bunte Breccia and fallout suevite) does not occur. Separation and gradation of ejected particles by atmosphere (fallout) seems improbable as the total ejecta mass per unit area at these distances is substantially higher than the mass of the involved atmosphere. Deposition of a suevitic layer as a viscous flow [20] seems also improbable, as viscosity of the flow with solid fragments (i.e. with temperature below the solidus) increases dramatically and prevents spreading to a few km from the transient cavity. We need another mechanism of the ejecta flow "fluidization". One possibility is a gas release (mainly water vapor from sediments) which allows dispersal of the smallest particles and suevite deposition above the ballistically deposited Bunte Breccia (similar to pyroclastic surges). Applications for planets Mars. Several attempts have been made to quantitatively describe the process of ejecta emplacement in formation of ramparts [21-25]. They dealt mainly with propagation of fluidized ejecta initially deposited

  5. Multisensory Emplaced Learning: Resituating Situated Learning in a Moving World

    Science.gov (United States)

    Fors, Vaike; Backstrom, Asa; Pink, Sarah

    2013-01-01

    This article outlines the implications of a theory of "sensory-emplaced learning" for understanding the interrelationships between the embodied and environmental in learning processes. Understanding learning as multisensory and contingent within everyday place-events, this framework analytically describes how people establish themselves as…

  6. Identifying the Barriers to Women's Agency in Domestic Violence: The Tensions between Women's Personal Experiences and Systemic Responses

    Directory of Open Access Journals (Sweden)

    Jo Aldridge

    2013-04-01

    Full Text Available Despite advances in knowledge and understanding about the impacts of domestic violence on women's lives, global research on violence against women shows there is a need for research that not only places women centre stage in research praxis, but also that involves them more collaboratively in genuine dialogue about their experiences, including their agentic stances. This is especially the case for marginalised and socially excluded women victims of domestic violence, such as those who are not known or do not present to services and who survive abusive relationships alone or with little outside support. Evidence from two studies reported here—secondary analysis of women with severe and enduring mental health problems and a collaborative narrative project with unsupported women victims of domestic violence—suggest that women's capacity for agency are compromised by a number of critical factors, and that these are also reflected in the tensions between micro–macro analyses and understanding of the impact of domestic violence on women. This article considers the barriers to women's agency from the women's perspective and in the context of broader, systemic dynamics, including the denial or obscuring of abuse by governments and states and the consequences of stringent fiscal retrenchment that put women at increased risk of domestic violence.

  7. RESEARCH: Influence of Social, Biophysical, and Managerial Conditions on Tourism Experiences Within the Great Barrier Reef World Heritage Area.

    Science.gov (United States)

    Shafer; Inglis

    2000-07-01

    / Managing protected areas involves balancing the enjoyment of visitors with the protection of a variety of cultural and biophysical resources. Tourism pressures in the Great Barrier Reef World Heritage Area (GBRWHA) are creating concerns about how to strike this balance in a marine environment. Terrestrial-based research has led to conceptual planning and management frameworks that address issues of human use and resource protection. The limits of acceptable change (LAC) framework was used as a conceptual basis for a study of snorkeling at reef sites in the GBRWHA. The intent was to determine if different settings existed among tourism operators traveling to the reef and, if so, to identify specific conditions relating to those settings. Snorkelers (N = 1475) traveling with tourism operations of different sizes who traveled to different sites completed surveys. Results indicated that snorkelers who traveled with larger operations (more people and infrastructure) differed from those traveling with smaller operations (few people and little on-site infrastructure) on benefits received and in the way that specific conditions influenced their enjoyment. Benefits related to nature, escape, and family helped to define reef experiences. Conditions related to coral, fish, and operator staff had a positive influence on the enjoyment of most visitors but, number of people on the trip and site infrastructure may have the greatest potential as setting indicators. Data support the potential usefulness of visitor input in applying the LAC concept to a marine environment where tourism and recreational uses are rapidly changing.

  8. Comparative Noise Performance of Portable Broadband Sensor Emplacements

    Science.gov (United States)

    Sweet, Justin; Arias-Dotson, Eliana; Beaudoin, Bruce; Anderson, Kent

    2015-04-01

    IRIS PASSCAL has supported portable broadband seismic experiments for close to 30 years. During that time we have seen a variety of sensor vaults deployed. The vaults deployed fall into two broad categories, a PASSCAL style vault and a Flexible Array style vault. The PASSCAL vault is constructed of materials available in-county and it is the Principle Investigator (PI) who establishes the actual field deployed design. These vaults generally are a large barrel placed in a ~1 m deep hole. A small pier, decoupled from the barrel, is fashioned in the bottom of the vault (either cement, paving stone or tile) for the sensor placement. The sensor is insulated and protected. Finally the vault is sealed and buried under ~30 cm of soil. The Flexible Array vault is provided to PIs by the EarthScope program, offering a uniform portable vault for these deployments. The vault consists of a 30 cm diameter by 0.75 cm tall piece of plastic sewage pipe buried with ~10 cm of pipe above grade. A rubber membrane covers the bottom and cement was poured into the bottom, coupling the pier to the pipe. The vault is sealed and buried under ~30 cm of soil. Cost, logistics, and the availability of materials in-country are usually the deciding factors for PIs when choosing a vault design and frequently trades are made given available resources. Recently a third type of portable broadband installation, direct burial, is being tested. In this case a sensor designed for shallow, direct burial is installed in a ~20 cm diameter by ~1 m deep posthole. Direct burial installation costs are limited to the time and effort required to dig the posthole and emplace the sensor. Our initial analyses suggest that direct burial sensors perform as well and at times better than sensor in vaults on both horizontal and vertical channels across a range of periods (installations supported by the PASSCAL program was anecdotal. A formal comparison of these various installation techniques is the subject of this poster

  9. Similarities in basalt and rhyolite lava flow emplacement processes

    Science.gov (United States)

    Magnall, Nathan; James, Mike; Tuffen, Hugh; Vye-Brown, Charlotte

    2016-04-01

    Here we use field observations of rhyolite and basalt lava flows to show similarities in flow processes that span compositionally diverse lava flows. The eruption, and subsequent emplacement, of rhyolite lava flows is currently poorly understood due to the infrequency with which rhyolite eruptions occur. In contrast, the emplacement of basaltic lava flows are much better understood due to very frequent eruptions at locations such as Mt Etna and Hawaii. The 2011-2012 eruption of Cordón Caulle in Chile enabled the first scientific observations of the emplacement of an extensive rhyolite lava flow. The 30 to 100 m thick flow infilled a topographic depression with a negligible slope angle (0 - 7°). The flow split into two main channels; the southern flow advanced 4 km while the northern flow advanced 3 km before stalling. Once the flow stalled the channels inflated and secondary flows or breakouts formed from the flow front and margins. This cooling rather than volume-limited flow behaviour is common in basaltic lava flows but had never been observed in rhyolite lava flows. We draw on fieldwork conducted at Cordón Caulle and at Mt Etna to compare the emplacement of rhyolite and basaltic flows. The fieldwork identified emplacement features that are present in both lavas, such as inflation, breakouts from the flow font and margins, and squeeze-ups on the flow surfaces. In the case of Cordón Caulle, upon extrusion of a breakout it inflates due to a combination of continued lava supply and vesicle growth. This growth leads to fracturing and breakup of the breakout surface, and in some cases a large central fracture tens of metres deep forms. In contrast, breakouts from basaltic lava flows have a greater range of morphologies depending on the properties of the material in the flows core. In the case of Mt Etna, a range of breakout morphologies are observed including: toothpaste breakouts, flows topped with bladed lava as well as breakouts of pahoehoe or a'a lava. This

  10. Experimental studies of heat transfer at the dynamic magma ice/water interface: Application to subglacially emplaced lava

    Science.gov (United States)

    Oddsson, Björn; Gudmundsson, Magnús T.; Sonder, Ingo; Zimanowski, Bernd; Schmid, Andrea

    2016-05-01

    Experiments simulating processes operating in volcano-ice interactions were carried out to explain and quantify lava thermal properties and processes of heat transfer from pure lava melt to water and ice and from hot crystalline lava to water. The samples used (70-200 g) were obtained from an intermediate lava flow (benmoreite-trachyte) that was emplaced under and within the outlet glacier Gígjökull in the 2010 eruption of Eyjafjallajökull. Experiments involved settings with direct contact between ice and lava, and settings where melt and ice were separated by a few centimeters. Direct contact involved melt being emplaced on ice and ice placed on melt. The direct contact experiments provided initial heat flux of up to 900 kW m-2 at an initially lava melt surface temperature of 1100°C, declining to rock experiments provided thermal conductivity values of 1.2-1.7 W m-1K-1 and diffusivity of about 9 × 10-7 m2s-1. Values for heat flux obtained in these experiments are in the same range as those obtained from field observations of the lava emplacement in the Eyjafjallajökull 2010 eruption.

  11. Emplacement of Volcanic Domes on Venus and Europa

    Science.gov (United States)

    Quick, Lynnae C.; Glaze, Lori S.; Baloga, Steve M.

    2015-01-01

    Placing firmer constraints on the emplacement timescales of visible volcanic features is essential to obtaining a better understanding of the resurfacing history of Venus. Fig. 1 shows a Magellan radar image and topography for a putative venusian lava dome. 175 such domes have been identified, having diameters that range from 19 - 94 km, and estimated thicknesses as great as 4 km [1-2]. These domes are thought to be volcanic in origin [3], having formed by the flow of a viscous fluid (i.e., lava) onto the surface. Among the unanswered questions surrounding the formation of Venus steep-sided domes are their emplacement duration, composition, and the rheology of the lava. Rheologically speaking, maintenance of extremely thick, 1-4 km flows necessitates higher viscosity lavas, while the domes' smooth upper surfaces imply the presence of lower viscosity lavas [2-3]. Further, numerous quantitative issues, such as the nature and duration of lava supply, how long the conduit remained open and capable of supplying lava, the volumetric flow rate, and the role of rigid crust in influencing flow and final morphology all have implications for subsurface magma ascent and local surface stress conditions. The surface of Jupiter's icy moon Europa exhibits many putative cryovolcanic constructs [5-7], and previous workers have suggested that domical positive relief features imaged by the Galileo spacecraft may be volcanic in origin [5,7-8] (Fig. 2). Though often smaller than Venus domes, if emplaced as a viscous fluid, formation mechanisms for europan domes may be similar to those of venusian domes [7]. Models for the emplacement of venusian lava domes (e.g. [9-10]) have been previously applied to the formation of putative cryolava domes on Europa [7].

  12. Barriers to HIV Testing Among Young Men Who Have Sex With Men (MSM): Experiences from Clark County, Nevada.

    Science.gov (United States)

    Pharr, Jennifer R; Lough, Nancy L; Ezeanolue, Echezona E

    2015-11-03

    Clark County, Nevada had a 52% increase in newly diagnosed HIV infections in young people age 13-24 with 83% of the new diagnoses in this age group being men who have sex with men (MSM). HIV testing and counseling is critical for HIV prevention, care and treatment, yet young people are the least likely to seek HIV testing. The purpose of this study was to identify barriers and facilitators to HIV testing experienced by young MSM in Clark County, Nevada. We conducted a qualitative focus group discussion to identify barriers and facilitators to HIV testing among eleven young MSM in March, 2015. The primary barrier to HIV testing identified by the group was a lack of awareness or knowledge about testing for HIV. Other barriers within the person included: fear of results, fear of rejection, and fear of disclosure. Barriers identified within the environment included: access issues, stigma, and unfriendly test environments for young people. In addition to increasing awareness, intervention to increase HIV testing among MSM young people should incorporate access to testing in environments where the adolescents are comfortable and which reduces stigma. HIV testing sites should be convenient, accessible and young person/gay friendly.

  13. Destruction of the peridotite-eclogite liquidus barrier during mantle magma differentiation (experiment at 7.0 GPa).

    Science.gov (United States)

    Butvina, Dr

    2012-04-01

    The main purpose of this paper is an experimental study of phase relationships in the model system forsterite-dioside-jadeite at pressure of 7 GPa and foundation of possible physico-chemical correct transitions between peridotite and eclogite parageneses with overcoming liquidus "eclogite" thermal barrier. To construct a diagram of a ternary system forsterite-diopside-jadeite it is necessary to study its boundary binary sections forsterite-jadeite and fosterite-diopside as well as a number of internal polythermic sections. The section jadeite-diopside at 7 GPa has been studied earlier and it is characterized by the unlimited miscibility of jadeite and diopside components in solid and liquid states. The experimental results obtained at the initial stage of the investigation of this problem can be characterized as follows. Forsterite-jadeite section. The experiments in this section have been done in the temperature range of 1100-18000C on which basis the construction of fusibility diagram of the system forsterite-jadeite at 7 GPa has been started. The obtained experimental data testify to the existence in the system of the liquidus fields Fo + L, GrtSS + L and CpxSS (on the basis of jadeite phase) +L, as well as show indirectly a possible appearance of orthopyroxene as a liquidus phase. In subsolidus experiments olivine-bearing assemblages on the basis of the paragenesis Ol+Grt+Opx+Cpx are found. Garnet there is not a pure pyrope, but has the molecule Na2MgSi5O12 (Na-majorite) what manifests itself in the direct correlation of Na and Si in the equations of this phase. OpxSS is not a pure enstatite, but forms a complicated solid solution En+Jd+Mg-Ts. With jadeite content increase in the system olivine-bearing assemblages transfer into non-olivine ones, up to the assemblage Cpx + Grt (jadeite-clinopyroxene has also enstatite component) being indirect evidence of a peritectic character of solidus in this system) what has also been shown earlier in (Gasparik et al., 1997

  14. Experiences and barriers to Health-Related Quality of Life following liver transplantation: a qualitative analysis of the perspectives of pediatric patients and their parents

    Directory of Open Access Journals (Sweden)

    Taylor Rachel

    2010-12-01

    Full Text Available Abstract This paper examines health-related quality of life (HRQOL experiences and barriers facing young people who have received a liver transplant (LT. Semi-structured qualitative interviews were conducted with children and adolescents who have undergone LT and their parents. Findings indicate that LT fosters substantially improved child and adolescent HRQOL; however, young people also experience challenges such as difficulties with medication compliance, self-management of care routines, physical activity restrictions, and undesirable medical procedures. Implications and recommendations for clinical practice and research are discussed.

  15. Internal fabrics in magmatic plutons emplaced in extended brittle crust - insight from analogue models with AMS (Anisotropy of Magnetic Susceptibility)

    Science.gov (United States)

    Mirzaei, Masoud; Zavada, Prokop; Machek, Matej; Roxerova, Zuzana

    2016-04-01

    Magma emplacement in extended brittle crust was simulated by injecting plaster of Paris (magma) into a large sandbox with central deformable rubber sheet. Analog magma is during the experiments injected through small circular inlet cut in the center of the elastic sheet. Injection force oscillation during the steadily evacuating analog magma was recorded during the experiments and regularly showed 3-4 increases followed by a quick drop. The recorded oscillation amplitude is largest for static injection without extension of the sandbox, which formed a columnar body with concentric and zonal internal fabric. Experiments including normal or oblique 20% extension resulted in along rift axis elongated oblate ellipsoidal pluton with rift parallel ridges in the top part of the pluton. Inspection of horizontal profiles show bone-shaped internal zoning patterns limited by conjugate sets of shear zones. Orientation of these internal shear zones is correlated with the sand-clock fault pattern developed in the overburden sand pack. Another set of shear zones parallel with the long axes of the plutons (rift axis) are associated with successive emplacement of distinct plaster pulses during the buildup of the entire body. The innermost lastly emplaced pulses of plaster display weak vertical magnetic fabrics with vertical lineations, while the outer shells of already emplaced plaster reveal stronger and margin parallel oblate magnetic fabrics with subhorizontal lineations. We interpret the vertical innermost fabrics as a result of active ascent of plaster from the injection inlet, while the fabrics in the outer zones likely reflect push due to inflation of the inner domain reflected in the reworking of the magnetic fabric.

  16. Paleomagnetism in the Determination of the Emplacement Temperature of Cerro Colorado Tuff Cone, El Pinacate Volcanic Field, Sonora, Mexico.

    Science.gov (United States)

    Rodriguez Trejo, A.; Alva-Valdivia, L. M.; Vidal Solano, J. R.; Garcia Amador, B.; Gonzalez-Rangel, J. A.

    2014-12-01

    Cerro Colorado Maar is located at the World Heritage Site, biosphere reserve El Pinacate and Gran Desierto del Altar, at the NNW region of Sonora, Mexico (in El Pinacate Volcanic Field). It is a tuff cone, about 1 km diameter, result of several phreatomagmatic episodes during the late Quaternary. We report paleomagnetic and rock magnetic properties from fusiform volcanic bombs obtained from the borders of Cerro Colorado. This study is based in the thermoremanent magnetization TRM normally acquired by volcanic rocks, which can be used to estimate the emplacement temperature range. We performed the experiments on 20 lithic fragments (10 cm to 20 cm approximately), taking 6-8 paleomagnetic cores from each. Rock magnetic experiments (magnetic susceptibility vs. temperature (k-T), hysteresis curves and FORC analysis, shows that the main magnetic mineral carriers of magnetization are titanomagnetite and titanohematite in different levels of intergrowth. The k-T curves suggest in many cases, only one magnetic phase, but also in other cases a second magnetic phase. Thermal demagnetization was used to demagnetize the specimens in detailed short steps and make a well-defined emplacement temperature determination ranges. We found that temperature emplacement determination range for these two magnetic phases is between 350-450 °C, and 550-580 °C, respectively. These results are consistent with those expected in an eruption of Surtsey type, showing a distinct volcanic activity compared to the other craters from El Pinacate volcanic field.

  17. Kimberlite emplacement models — The implications for mining projects

    Science.gov (United States)

    Jakubec, Jaroslav

    2008-06-01

    The significance of the emplacement model for kimberlite pipes, or sheets, is commonly recognized in resource geology. However, its importance is not always appreciated in the mine design process. The fact is that knowledge of the orebody geometry, character of the contact zones, internal structures, rock mass competency and distribution of inclusions could directly influence the selection of the underground mining method, pit wall stability, dilution, treatability, and the dewatering strategy. The problems are exacerbated in smaller pipes and narrower sheets, and in more irregular shapes; they are more apparent in underground mining as opposed to open cast. Various kimberlite emplacement processes have a major impact on the nature of the kimberlite orebody and host rocks that will influence the mine design and mining strategy. Failure to understand these processes can adversely affect the economic outcome for developing a mine. It is therefore important to investigate those processes in order to better characterize the mining constraints and risks, and more accurately predict the mine's economic viability.

  18. Three integrated photovoltaic/sound barrier power plants. Construction and operational experience; Drei integrierte PV-Schallschutz Versuchsfelder. Bau und Erprobung

    Energy Technology Data Exchange (ETDEWEB)

    Nordmann, T.; Froelich, A.; Clavadetscher, L.

    2002-07-01

    After an international ideas competition by TNC Switzerland and Germany in 1996, six companies where given the opportunity to construct a prototype of their newly developed integrated PV-sound barrier concepts. The main goal was to develop highly integrated concepts, allowing the reduction of PV sound barrier systems costs, as well as the demonstration of specific concepts for different noise situations. This project is strongly correlated with a German project. Three of the concepts of the competition are demonstrated along a highway near Munich, constructed in 1997. The three Swiss installations had to be constructed at different locations, reflecting three typical situations for sound barriers. The first Swiss installation was the world first Bi-facial PV-sound barrier. It was built on a highway bridge at Wallisellen-Aubrugg in 1997. The operational experience of the installation is positive. But due to the different efficiencies of the two cell sides, its specific yield lies somewhat behind a conventional PV installation. The second Swiss plant was finished in autumn 1998. The 'zig-zag' construction is situated along the railway line at Wallisellen in a densely inhabited area with some local shadowing. Its performance and its specific yield is comparatively low due to a combination of several reasons (geometry of the concept, inverter, high module temperature, local shadows). The third installation was constructed along the motor way A1 at Bruettisellen in 1999. Its vertical panels are equipped with amorphous modules. The report show, that the performance of the system is reasonable, but the mechanical construction has to be improved. A small trial field with cells directly laminated onto the steel panel, also installed at Bruettisellen, could be the key development for this concept. This final report includes the evaluation and comparison of the monitored data in the past 24 months of operation. (author)

  19. Barriers to HIV Testing Among Young Men Who Have Sex With Men (MSM): Experiences from Clark County, Nevada

    OpenAIRE

    Pharr, Jennifer R.; Lough, Nancy L.; Echezona E Ezeanolue

    2015-01-01

    Clark County, Nevada had a 52% increase in newly diagnosed HIV infections in young people age 13-24 with 83% of the new diagnoses in this age group being men who have sex with men (MSM). HIV testing and counseling is critical for HIV prevention, care and treatment, yet young people are the least likely to seek HIV testing. The purpose of this study was to identify barriers and facilitators to HIV testing experienced by young MSM in Clark County, Nevada. We conducted a qualitative focus group ...

  20. A model for radial dike emplacement in composite cones based on observations from Summer Coon volcano, Colorado, USA

    Science.gov (United States)

    Poland, Michael P.; Moats, W.P.; Fink, J.H.

    2008-01-01

    We mapped the geometry of 13 silicic dikes at Summer Coon, an eroded Oligocene stratovolcano in southern Colorado, to investigate various characteristics of radial dike emplacement in composite volcanoes. Exposed dikes are up to about 7 km in length and have numerous offset segments along their upper peripheries. Surprisingly, most dikes at Summer Coon increase in thickness with distance from the center of the volcano. Magma pressure in a dike is expected to lessen away from the pressurized source region, which would encourage a blade-like dike to decrease in thickness with distance from the center of the volcano. We attribute the observed thickness pattern as evidence of a driving pressure gradient, which is caused by decreasing host rock shear modulus and horizontal stress, both due to decreasing emplacement depths beneath the sloping flanks of the volcano. Based on data from Summer Coon, we propose that radial dikes originate at depth below the summit of a host volcano and follow steeply inclined paths towards the surface. Near the interface between volcanic cone and basement, which may represent a neutral buoyancy surface or stress barrier, magma is transported subhorizontally and radially away from the center of the volcano in blade-like dikes. The dikes thicken with increasing radial distance, and offset segments and fingers form along the upper peripheries of the intrusions. Eruptions may occur anywhere along the length of the dikes, but the erupted volume will generally be greater for dike-fed eruptions far from the center of the host volcano owing to the increase in driving pressure with distance from the source. Observed eruptive volumes, vent locations, and vent-area intrusions from inferred post-glacial dike-fed eruptions at Mount Adams, Washington, USA, support the proposed model. Hazards associated with radial dike emplacement are therefore greater for longer dikes that propagate to the outer flanks of a volcano. ?? Springer-Verlag 2007.

  1. Subsurface barrier validation with the SEAtrace{trademark} system

    Energy Technology Data Exchange (ETDEWEB)

    Sandra Dalvit Dunn; William Lowry; Veraun Chipman

    1999-09-01

    Under contract to the Department of Energy, Science and Engineering Associates has completed development and testing of a subsurface barrier verification and monitoring system. This system, called SEAtrace{trademark}, is able to locate and size leaks with a high degree of accuracy in subsurface barriers that are emplaced in an unsaturated medium. It uses gaseous tracer injection, in-field real-time monitoring, and real time data analysis to evaluate barrier integrity. The approach is: Conservative as it measures vapor leaks in a containment system whose greatest risk is posed by liquid leaks; Applicable to any impermeable type of barrier emplacement technology in the unsaturated zone; Inexpensive as it uses readily available, non-toxic, nonhazardous gaseous tracers, does not require an inordinately large number of sampling points, and injection and sampling points can be emplaced by direct push techniques; Capable of assessing not only a barrier's initial integrity, but can also provide long-term monitoring. To date, six demonstrations of the system have been completed. Results from two of the demonstrations are detailed in this report. They include the final developmental demonstration of the SEAtrace system and a comparison demonstration of two tracer based verification technologies. The final developmental demonstration of SEAtrace was completed at a naval facility in Brunswick, Maine. The demonstration was funded solely by the DOE and was performed in cooperation with the US Navy, the Environmental Protection Agency, and the Maine Department of Environmental Protection.

  2. Barriers to diagnosis of a rare neurological disorder in China--lived experiences of Rett syndrome families.

    Science.gov (United States)

    Lim, Faye; Downs, Jenny; Li, Jianghong; Bao, Xin-Hua; Leonard, Helen

    2012-01-01

    Rett syndrome is a rare neurological disorder affecting girls and usually caused by a mutation on the MECP2 gene. It is estimated that approximately 1,000 girls are born every year in China with Rett syndrome but far fewer have received a diagnosis. Fourteen of 74 Chinese families known to the International Rett Syndrome Phenotype Database participated in this qualitative study. Telephone interviews were conducted in Mandarin to explore pathways to a diagnosis of Rett syndrome in China and associated barriers. Families consulted multiple clinical centers and eventually received a diagnosis at a centrally located hospital. Over the course of this pathway, families encountered lack of knowledge and diagnostic expertise for Rett syndrome at local levels and a heavily over-burdened hospital system. There was a paucity of information available to guide management of this rare disorder after the diagnosis had been received. Our study suggests that the frustrations experienced by families could in part be addressed by the provision of information, education, and training related to Rett syndrome for clinicians, additional resources to allow clinicians to request genetic testing for confirmation of the clinical diagnosis and for information and support services for families.

  3. Diabetes and diet: Managing dietary barriers.

    NARCIS (Netherlands)

    Friele, R.D.

    1989-01-01

    This thesis reports on the barriers diabetic patients experience with their diet, and the ways they cope with these barriers. A dietary barrier is a hinderance to a person's well-being, induced by being advised a diet. First inventories were made of possible dietary barriers and ways of coping with

  4. FEBEX-DP. Dismantling the ''full-scale engineered barrier experiment'' after 18 years of operation at the Grimsel Test Site, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Kober, Florian; Gaus, Irina [Nagra, Wettingen (Switzerland)

    2015-07-01

    The FEBEX experiment at the Grimsel Test Site (GTS) consists of an in-situ full-scale engineered barrier system (EBS) test for the disposal of high-level waste (HLW). It is performed under natural conditions in crystalline rock in which the canisters are placed horizontally in drifts and are surrounded by a clay barrier constructed of highly compacted bentonite blocks. A partial dismantling and sampling of the EBS was carried out during 2002. Heating of the FEBEX started in 1997 and since then a constant temperature of 100 deg C has been maintained, while the bentonite buffer has been slowly hydrating in a natural way. A total of 632 sensors in the bentonite barrier, the rock mass, the heaters and the service zone record temperature, water saturation, humidity, total pressure, displacement, and water pressure. The hydration pattern is relatively symmetric, with no major differences along the axis. Although the host rock is characterized by heterogeneities with zones of higher permeability, the resaturation process is driven by the suction of the bentonite rather than by the availability of water in the rock, especially in the early phase. After 17 years, the water content in the buffer close to the heater still continues to increase slowly. The hydraulic pore pressures in the buffer and the geosphere have practically stabilized. The total pressure in general continues to increase in most points into the buffer, where in some parts pressures of over 6 MPa are registered. The long monitoring phase and the partial dismantling in 2002 indicate that the EBS has largely performed as expected and the major processes and couplings affecting the buffer saturation during the initial thermal period identified prior to the start of the experiment have been confirmed. A comprehensive report documents and reviews the state of the FEBEX (Lanyon and Gaus, 2013). After 18 years of operation the experiment will be excavated and dismantled in 2015. The main objectives of the FEBEX

  5. Barriers and Enablers to the Use of Virtual Worlds in Higher Education: An Exploration of Educator Perceptions, Attitudes and Experiences

    Science.gov (United States)

    Gregory, Sue; Scutter, Sheila; Jacka, Lisa; McDonald, Marcus; Farley, Helen; Newman, Chris

    2015-01-01

    Three-dimensional (3D) virtual worlds have been used for more than a decade in higher education for teaching and learning. Since the 1980s, academics began using virtual worlds as an exciting and innovative new technology to provide their students with new learning experiences that were difficult to provide any other way. But since that time,…

  6. Recurrent uranium relocations in distal turbidites emplaced in pelagic conditions

    Science.gov (United States)

    Colley, S.; Thomson, J.

    1985-11-01

    The sediments of the Madeira Abyssal Plain, east of Great Meteor Seamount, are dominated by distal turbidite deposition. While the turbidites exhibit a wide compositional range (25-80% CaCO 3), individual examples can be correlated over a wide area and are relatively homogenous. Organic C oxidation, by bottom water oxygen, proceeds from the turbidite tops downwards after emplacement in pelagic conditions, and the progress of this oxidation front is marked by a sharp colour contrast in the sediments ( WILSONet al., 1985). In turbidites with C org ≫ 0.5%, redistribution of authigenic U occurs to form a concentration peak (4-9 ppm U), just below the oxidation front or colour change. Several tens μg U/cm 2 may be mobilised, and in all examples studied ≫60% of the remobilised U is relocated into the peak. Following burial by subsequent turbidites, such U concentration peaks are persistent as relict indicators of their extinct oxidation fronts for at least 2 × 10 5 years. In the case of thin turbidites where labile C org is almost exhausted, the U peaks may be located in underlying sedimentary units because of their relationship to the oxidation front. A redox mechanism for U peak formation is suggested from these data rather than a complexation with organic matter.

  7. Emplacement mechanism of Linglong granitoid complex, Shandong Peninsula, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Linglong granitoid complex (LGC) is composed of four major plutonic units that intruded and cooled in the Middle Jurassic (170-155 Ma). Gravity-anomaly modeling indicates that the LGC is a sheet-like laccolith, less than 10 km thick, that dips shallowly below the surface toward the Tancheng-Lujiang (Tan-Lu) fault, a major lithospheric structure in Eastern China. Measurements of foliation in the field and measurements of planar and linear magnetic fabrics from the study of anisotropy of magnetic susceptibility in the LGC indicate that foliation is dominantly shallowly dipping and magnetic lineation is mainly parallel to the dip direction of the laccolith toward the Tan-Lu fault zone. The trend of lineations is consistent with flow of magma up the thrust to reach shallower levels. The magma of the LGC probably originated by crustal melting within the Tan-Lu fault zone and the emplacement of magma occurred along a shallowly-dipping thrust that drained the Tan-Lu fault zone, the mechanism of which is mainly dike-fed model.

  8. Constructing bottom barriers with met grouting

    Energy Technology Data Exchange (ETDEWEB)

    Shibazaki, M.; Yoshida, H. [Chemical Grouting Company, Tokyo (Japan)

    1997-12-31

    Installing a bottom barrier using conventional high pressure jetting technology and ensuring barrier continuity is challenging. This paper describes technology that has been developed and demonstrated for the emplacement of bottom barriers using pressures and flow rates above the conventional high pressure jetting parameters. The innovation capable of creating an improved body exceeding 5 meters in diameter has resulted in the satisfying connection and adherence between the treated columns. Besides, the interfaces among the improved bodies obtain the same strength and permeability lower than 1 x 10{sup -7} cm/sec as body itself. A wide variety of the thickness and the diameter of the improved mass optimizes the application, and the method is nearing completion. The paper explains an aspect and briefs case histories.

  9. Emplacement mechanism of Linglong granitoid complex, Shandong Peninsula, China

    Institute of Scientific and Technical Information of China (English)

    WAN; Tianfeng

    2001-01-01

    , Wang Bincheng, Xu Jinfang et al., Geochemical background research of lead isotopic for regional rock in Eastern Shandong, Collection of Geology and Seeking Mineral Deposits (in Chinese with English abstract), 1994, 9(1): 65-77.[11]Berger, A. R., Pitcher, W. S., The structure in granitoid rocks: A review on the granitic structure, Proceedings of the Geologist Association, 1972, 81(part 3): 421-461.[12]Shaw, H. R., Fracture mechanism of magma transport from the mantle to the surface, in Physics of Magmatic Process (ed. Hargraves. R. B.), Princeton: Princeton University Press, 1980, 201-264.[13]Ramsay, J. G., Emplacement mechanics of the Chindamora Batholith, Zimbabwe, J. Structural Geology, 1981, 3: 93-105.[14]Castrol, A., On granitoid emplacement and related structure: A review, Geol. Rundsch., 1987, 76: 101-124.[15]Apperson, K. D., Stress fields of the overriding plate at convergent margins and beneath active volcanic areas, Science, 1991, 254: 670-678.[16]Tikoff, B., Teyssier, C., Crustal-scale, an echelon-shear tensional bridge: A possible solution to the batholithic room problem, Geology, 1992, 20: 927-930.[17]Bureau of Geology and Mineral Resources of Shandong Province, Regional Geology of Shandong Province (in Chinese with English abstract), Beijing: Geological Publishing House, 1991, 595.[18]Miao Laicheng, Luo Zhenkuan, Guan Kan et al., The implication of the SHRIMP U-Pb age in zircon to the petrogenesis of the Linglong granite, East Shandong Province, Acta Petrologica Sinica (in Chinese with English abstract), 1998, 14(2): 198-206.[19]Bathal, R. S., Magnetic anisotropy of rocks, Earth Science Review, 1971, 7: 227-253.[20]Hrouda, F., Magnetic anisotropy of rocks and its application in geology and geophysics, Geophysical Survey, 1982, 5: 37-82.[21]Rochette, P., Jackson, M., Aubourg, C., Rock magnetism and the interpretation of anisotropy of magnetic susceptibility, Reviews of Geophysics, 1992, 30(3): 209-226.[22

  10. Transdomes: Emplacement of Migmatite Domes in Oblique Tectonic Settings

    Science.gov (United States)

    Teyssier, C. P.; Rey, P. F.; Whitney, D. L.; Mondy, L. S.; Roger, F.

    2014-12-01

    Many migmatite domes are emplaced within wrench corridors in which a combination of strike-slip and extensional detachment zones (pull-apart, extensional relay, or transfer zones) focus deep-crust exhumation. The Montagne Noire dome (France, Variscan Massif Central) exemplifies wrench-related dome formation and displays the following structural, metamorphic, and geochronologic characteristics of a 'transdome': the dome is elongate in the direction of extension; foliation outlines a double dome separated by a high-strain zone; lineation is shallowly plunging with a fairly uniform trend that parallels the strike of the high-strain zone; subdomes contain recumbent structures overprinted by upright folds that affected upward by flat shear zones associated with detachment tectonics; domes display a large syn-deformation metamorphic gradient from core (upper amphibolite facies migmatite) to margin (down to greenschist facies mylonite); some rocks in the dome core experienced isothermal decompression revealed by disequilibrium reaction textures, particularly in mafic rocks (including eclogite); and results of U-Pb geochrononology indicate a narrow range of metamorphic crystallization from core to mantling schist spanning ~10 Myr. 3D numerical modeling of transdomes show that the dome solicits a larger source region of partially molten lower crust compared to 2D models; this flowing crust creates a double-dome architecture as in 2D models but there are differences in the predicted thermal history and flow paths. In a transtension setting, flow lines converge at depth (radial-centripetal flow) toward the zone of extension and diverge at shallow levels in a more uniform direction that is imposed by upper crust motion and deformation. This evolution produces a characteristic pattern of strain history, progressive fabric overprint, and P-T paths that are comparable to observed dome rocks.

  11. Barriers and facilitators to evidence based care of type 2 diabetes patients: experiences of general practitioners participating to a quality improvement program

    Directory of Open Access Journals (Sweden)

    Hannes Karen

    2009-07-01

    Full Text Available Abstract Objective To evaluate the barriers and facilitators to high-quality diabetes care as experienced by general practitioners (GPs who participated in an 18-month quality improvement program (QIP. This QIP was implemented to promote compliance with international guidelines. Methods Twenty out of the 120 participating GPs in the QIP underwent semi-structured interviews that focused on three questions: 'Which changes did you implement or did you observe in the quality of diabetes care during your participation in the QIP?' 'According to your experience, what induced these changes?' and 'What difficulties did you experience in making the changes?' Results Most GPs reported that enhanced knowledge, improved motivation, and a greater sense of responsibility were the key factors that led to greater compliance with diabetes care guidelines and consequent improvements in diabetes care. Other factors were improved communication with patients and consulting specialists and reliance on diabetes nurse educators. Some GPs were reluctant to collaborate with specialists, and especially with diabetes educators and dieticians. Others blamed poor compliance with the guidelines on lack of time. Most interviewees reported that a considerable minority of patients were unwilling to change their lifestyles. Conclusion Qualitative research nested in an experimental trial may clarify the improvements that a QIP may bring about in a general practice, provide insight into GPs' approach to diabetes care and reveal the program's limits. Implementation of a QIP encounters an array of cognitive, motivational, and relational obstacles that are embedded in a patient-healthcare provider relationship.

  12. Understanding innovators' experiences of barriers and facilitators in implementation and diffusion of healthcare service innovations: a qualitative study

    Directory of Open Access Journals (Sweden)

    Barnett Julie

    2011-12-01

    Full Text Available Abstract Background Healthcare service innovations are considered to play a pivotal role in improving organisational efficiency and responding effectively to healthcare needs. Nevertheless, healthcare organisations encounter major difficulties in sustaining and diffusing innovations, especially those which concern the organisation and delivery of healthcare services. The purpose of the present study was to explore how healthcare innovators of process-based initiatives perceived and made sense of factors that either facilitated or obstructed the innovation implementation and diffusion. Methods A qualitative study was designed. Fifteen primary and secondary healthcare organisations in the UK, which had received health service awards for successfully generating and implementing service innovations, were studied. In-depth, semi structured interviews were conducted with the organisational representatives who conceived and led the development process. The data were recorded, transcribed and thematically analysed. Results Four main themes were identified in the analysis of the data: the role of evidence, the function of inter-organisational partnerships, the influence of human-based resources, and the impact of contextual factors. "Hard" evidence operated as a proof of effectiveness, a means of dissemination and a pre-requisite for the initiation of innovation. Inter-organisational partnerships and people-based resources, such as champions, were considered an integral part of the process of developing, establishing and diffusing the innovations. Finally, contextual influences, both intra-organisational and extra-organisational were seen as critical in either impeding or facilitating innovators' efforts. Conclusions A range of factors of different combinations and co-occurrence were pointed out by the innovators as they were reflecting on their experiences of implementing, stabilising and diffusing novel service initiatives. Even though the innovations

  13. Effects of Carbon Dioxide Hydrate Emplacement on Deep-Sea Foraminiferal Assemblages Abstract #1340h b33-1020

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, E R; Kennett, J P; Hill, T M; Barry, J P

    2005-12-01

    ABSTRACT Two studies, conducted in cooperation with the Monterey Bay Aquarium Research Institute (using the R/V Western Flyer and the ROV Tiburon), investigated effects of carbon dioxide hydrate emplacement and associated dissolution products on foraminifera at two sites (3600m and 3100m) off the California margin. Foraminifera are ideal for these investigations because of differing test composition (calcareous and agglutinated) and thicknesses, and diverse epifaunal and infaunal depth preferences. The pH of each site was monitored by Seabird CTDs. Suites of sediment push-cores were collected and stained (to distinguish live from dead). These included control cores and multiple experimental core types (corral, distal, and proximal). Core length differed between the two studies in part to assess the effective depth of penetration of CO2 within the sediments. Effects of CO2 emplacement on foraminiferal assemblages have been tracked both vertically (10-20cm below the sea floor) and horizontally (up to 50m from CO2 injection sites), and between live and dead individuals. Results from these experiments are in accordance on several major effects: 1) increased mortality and dissolution as a consequence of CO2 hydrate exposure; 2) total number of foraminifera in the sample decreases; and 3) resistance to dissolution varies with depth and species. Down-core trends (to 10cm bsf) for the 3600m study show: 1) an exponential decrease of tests with depths; 2) percent agglutinated forms decline and calcareous forms increasingly dominate with depth; 3) agglutinated diversity decreases with depth; and 3) assemblages in experimental cores become increasingly similar with depth to those in control cores. Down-core trends for the 3100m study show: 1) a uniform distribution of tests to a depth of 14cm; 2) below 14cm there is a linear increase in test abundance per centimeter; and 3) deep penetration of carbonate dissolution (up to 16cm) in assemblages in experimental cores. These

  14. Overcoming Language Barriers

    Science.gov (United States)

    De Buda, Yvonne

    1976-01-01

    Many family physicians in Canada experience language and cultural barriers between themselves and their patients. Several aspects of the ensuing problems are described and some practical suggestions for solutions are made. The importance of health education for new Canadians in the family physician's office as well as through the media and community projects is stressed. Imagesp68-ap68-bp70-a PMID:21308059

  15. Paleomagnetic and magnetic fabric studies of the San Gaspar ignimbrite, western Mexico—constraints on emplacement mode and source vents

    Science.gov (United States)

    Alva-Valdivia, L. M.; Rosas-Elguera, J.; Bravo-Medina, T.; Urrutia-Fucugauchi, J.; Henry, B.; Caballero, C.; Rivas-Sanchez, M. L.; Goguitchaichvili, A.; López-Loera, H.

    2005-10-01

    Paleomagnetic and magnetic fabric data for the 4.8 Ma San Gaspar ignimbrite, one of the largest in western Mexico, are used to investigate the source vents, emplacement mechanism and tectonics. Rock magnetic properties from distant parts of the ignimbrite are similar, suggesting relatively homogeneous mineralogy of the unit. Isothermal remanence and continuous susceptibility-temperature experiments point to low to medium-Ti titanomagnetites as the main magnetic carriers. Hysteresis ratio parameters of most samples fall in the pseudo-single-domain grain size region; wasp-waisted hysteresis loops were identified corresponding to high Hcr / Hc values. Stepwise thermal and alternating field demagnetization shows that secondary components are completely removed below 20 mT or 400 °C. Thereafter, the characteristic component is isolated with small within-site dispersion of mean direction ( α95 fabric supports that the ignimbrite welded and cooled in situ and was probably emplaced in a NW-SE rift zone from a single eruption center located south or east of a younger Pleistocene caldera in the area. Paleomagnetic, rock magnetic and ore microscopy data support the hypothesis that the extensive and widespread ignimbrite deposits in western Mexico correspond to a major explosive volcanic phase in the Pliocene.

  16. Paleomagnetic and magnetic fabric studies of the San Gaspar ignimbrite, western Mexico - constraints on emplacement mode and source vents

    Science.gov (United States)

    Rosas-Elguera, J.; Alva-Valdivia, L.; Goguitchaisvili, A.

    2004-12-01

    Paleomagnetic and magnetic fabric data for the 4.8 Ma San Gaspar ignimbrite, one of the largest in western Mexico, are used to investigate on the source vents and emplacement mechanism. Rock-magnetic properties are similar, suggesting relatively homogeneous mineralogy of the unit. Isothermal remanence and continuous susceptibility-temperature experiments point to low to medium-Ti titanomagnetite as the main ferromagnetic mineral. Hysteresis parameters of most samples fall in the pseudo-single-domain grain size region; wasp-waisted hysteresis loops were identified corresponding to high Hcr/Hc values. Stepwise thermal and alternating field demagnetization shows that secondary components are negligible, and always completely removed below 20 mT or 400°C. Thereafter, the characteristic component is isolated with small within-site dispersion of mean direction (á95fabric supports that the ignimbrite welded and cooled in situ and was probably emplaced in NW-SE rift zone from a single eruption center located south or east of a younger Pleistocene caldera. Paleomagnetic, rock-magnetic and ore microscopy data support the hypothesis that the extensive and widespread ignimbrite deposits in western Mexico correspond to a major explosive volcanic phase in the Pliocene.

  17. San Gaspar ignimbrite, western Mexico: Magnetic fabric and Paleomagnetic studies - constraints on emplacement mode and source vents

    Science.gov (United States)

    Caballero, C.; Alva-Valdivia, L. M.; Rosas-Elguera, J.

    2005-05-01

    Paleomagnetic and magnetic fabric data for the 4.8 Ma San Gaspar ignimbrite, one of the largest in western Mexico, are used to investigate on the source vents, emplacement mechanism and tectonics. The within-site consistency of directional features of magnetic fabric supports that the ignimbrite welded and cooled in situ and was probably emplaced in NW-SE rift zone from a single eruption center located south or east of a younger Pleistocene caldera. Paleomagnetic, rock-magnetic and ore microscopy data support the hypothesis that the extensive and widespread ignimbrite deposits in western Mexico correspond to a major explosive volcanic phase in the Pliocene Rock-magnetic properties are similar, suggesting relatively homogeneous mineralogy of the unit. Isothermal remanence and continuous susceptibility-temperature experiments point to low to medium-Ti titanomagnetite as the main ferromagnetic mineral. Hysteresis parameters of most samples fall in the pseudo-single-domain grain size region; wasp-waisted hysteresis loops were identified corresponding to high Hcr/Hc values. Stepwise thermal and alternating field demagnetization shows that secondary components are negligible, and always completely removed below 20 mT or 400° C. The characteristic component is isolated in all sites with small within-site dispersion of mean direction in most of them (alfa 95 less than 10 at 7 out of 10 sites).

  18. FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock

    Energy Technology Data Exchange (ETDEWEB)

    Alberid, J.; Barcala, J. M.; Campos, R.; Cuevas, A. M.; Fernandez, E. [Ciemat. Madrid (Spain)

    2000-07-01

    FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

  19. The influence of negative ions in helium-oxygen barrier discharges: II. 1D fluid simulation and adaption to the experiment

    Science.gov (United States)

    Nemschokmichal, Sebastian; Tschiersch, Robert; Meichsner, Jürgen

    2016-10-01

    A 1D fluid simulation was developed to investigate the influence of negative ions in a helium-oxygen barrier discharge between two glass plates at a distance of 3~\\text{mm} . The paper describes setting up the simulation for a pressure of 500~\\text{mbar} and an admixture of 400~\\text{ppm} oxygen to helium. In order to enable the comparison with laser photodetachment experiments, the simulation is adapted to the experimentally observed discharge current and gap voltage by varying gas temperature, flux of thermally desorpted electrons and secondary electron emission coefficients. The discharge is characterized by evaluation of the most important elementary collision processes as well as the kinetics of the charged species. Besides, the influence of long-living species on the discharge behavior is taken into account by long-time simulations. The negative ions are characterized by their spatio-temporal distribution in the gap and their production and loss processes. The comparison between simulations without and with consideration of negative ions reveals the importance of negative ions on the discharge development.

  20. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.J.

    1980-05-01

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed.

  1. pH homeostasis during coral calcification in a free ocean CO2 enrichment (FOCE) experiment, Heron Island reef flat, Great Barrier Reef.

    Science.gov (United States)

    Georgiou, Lucy; Falter, James; Trotter, Julie; Kline, David I; Holcomb, Michael; Dove, Sophie G; Hoegh-Guldberg, Ove; McCulloch, Malcolm

    2015-10-27

    Geochemical analyses (δ(11)B and Sr/Ca) are reported for the coral Porites cylindrica grown within a free ocean carbon enrichment (FOCE) experiment, conducted on the Heron Island reef flat (Great Barrier Reef) for a 6-mo period from June to early December 2010. The FOCE experiment was designed to simulate the effects of CO2-driven acidification predicted to occur by the end of this century (scenario RCP4.5) while simultaneously maintaining the exposure of corals to natural variations in their environment under in situ conditions. Analyses of skeletal growth (measured from extension rates and skeletal density) showed no systematic differences between low-pH FOCE treatments (ΔpH = ∼-0.05 to -0.25 units below ambient) and present day controls (ΔpH = 0) for calcification rates or the pH of the calcifying fluid (pHcf); the latter was derived from boron isotopic compositions (δ(11)B) of the coral skeleton. Furthermore, individual nubbins exhibited near constant δ(11)B compositions along their primary apical growth axes (±0.02 pHcf units) regardless of the season or treatment. Thus, under the highly dynamic conditions of the Heron Island reef flat, P. cylindrica up-regulated the pH of its calcifying fluid (pHcf ∼8.4-8.6), with each nubbin having near-constant pHcf values independent of the large natural seasonal fluctuations of the reef flat waters (pH ∼7.7 to ∼8.3) or the superimposed FOCE treatments. This newly discovered phenomenon of pH homeostasis during calcification indicates that coral living in highly dynamic environments exert strong physiological controls on the carbonate chemistry of their calcifying fluid, implying a high degree of resilience to ocean acidification within the investigated ranges.

  2. A Paleomagnetic Study of Late Cretaceous Ophiolites in SE Turkey: implications for palaeolatitudes of S Neotethyan spreading centers and emplacement-related tectonic rotations

    Science.gov (United States)

    Mualla, Cinku; Timur, Ustaömer; Osman, Parlak; Mumtaz, Hisarli

    2016-04-01

    Two E-W trending ophiolite belts crop out in SE Turkey, The southerly located ophiolites (Hatay, Koçali) were emplaced onto the Arabian Platform in Late Cretaceous whereas the northerly located ophiolites (Göksun, İspendere, Kömürhan, Guleman) were underthrust the S Tauride margin (i.e. Malatya-Keban Platform) in Late Cretaceous. Different tectonic models exist in the literature for the origin of these different ophiolite belts that we test here by a detailed palaomagnetic study: a) all the ophiolites in Turkey, including those in the study area were rooted from a single ocean basin to the N (i.e. the N Neotethyan Ocean Basin); b) all the ophiolites in SE Turkey were derived from the S Neotethyan Ocean Basin; c) the two ophiolite belts in SE Turkey are believed to have rooted from two different ocean basins; the Berit ocean to the north and the S Neotethys to the S. Our palaeomagnetic study from 72 different sites was focused on to the sheeted dyke complex, cumulate gabbros and extrusive sequences where available of each ophiolite from the N and S belts. We also sampled the unconformable cover units to distinguish emplacement related tectonic rotations from post-emplacement tectonic rotations. Here we report our first results obtained from the Göksun Ophiolite of the northern belt and the Hatay Ophiolite of the southern belt. Rock magnetic experiments showed evidence od magnetite/titanomagnetite as the main magnetic carriers at the majority of sites. Progressive thermal and alternating demagnetization revealed that the characteristic remanent component is removed between 500 and 580 ?C or 30-100 mT, respectively. Our new paleomagnetic results from the ophiolitic rocks emplaced in Arabian platform and the SE Anatolia show important implications to the spreading centre of the former ocean (s). Large counterclockwise rotations up to 100° are obtained from the sheeded dykes of the Hatay ophiolite in the Arabian plate with a paleolatitude of ˜16° , in contrast

  3. Engineered Barrier System: Physical and Chemical Environment

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-04-26

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  4. The Montagne Noire migmatitic dome emplacement (French Massif Central): new insights from petrofabric and AMS studies

    Science.gov (United States)

    Charles, Nicolas; Faure, Michel; Chen, Yan

    2009-11-01

    In the southern French Massif Central, the Montagne Noire axial zone is a NE-SW elongated granite-migmatite dome emplaced within Visean south-verging recumbent folds and intruded by syn- to late-migmatization granitoids. The tectonic setting of this dome is still disputed, thus several models have been proposed. In order to better understand the emplacement mechanism of this dome, petrofabric and Anisotropy of Magnetic Susceptibility (AMS) studies have been carried out. In the granites and migmatites that form the dome core, magmatic texture and to a lesser extent weak solid-state texture are dominant. As a paramagnetic mineral, biotite is the main carrier of the magnetic susceptibility. On the basis of 135 AMS sites, the magnetic fabrics appear as independent of the lithology but related to the dome architecture. Coupling our results with previous structural and geochronological studies, allows us to propose a new emplacement model. Between 340-325 Ma, the Palaeozoic series underwent a compressional deformation represented by nappes and recumbent folds involving the thermal event leading to partial melting. Until ˜325-310 Ma, the dome emplacement was assisted by diapiric processes. An extensional event took place at ˜300 Ma, after the emplacement of the late to post-migmatitic granitic plutons. In the northeast side of the dome, a brittle normal-dextral faulting controlled the opening of the Graissessac coal basin.

  5. Basic and clinical research on the regulation of the intestinal barrier by Lactobacillus and its active protein components: a review with experience of one center.

    Science.gov (United States)

    Liu, Zhi-Hua; Kang, Liang; Wang, Jian-Ping

    2014-12-01

    Probiotics got protective effects on the intestinal barrier. Our present study is to review the basic and clinical progress on the regulation of the intestinal barrier by Lactobacillus and its active protein components, combing the study of our center. Our study have isolated the active component of micro integral membrane protein (MIMP) within the media place of the integral membrane protein of Lactobacillus plantarum, which was verified about the protective effects against the intestinal epithelial dysfunction. On the other hand, we also found the effects of perioperative use of probiotics in the prevention and treatment of postoperative intestinal barrier dysfunction, and reduction of the postoperative infective complications. In this review, we would like to report the founding of our center, involving in the basic and clinical research progress of regulation of intestinal barrier by Lactobacillus and its active protein component MIMP. Furthermore, we may also promote our following studies about the MIMP and its clinical verification.

  6. Waste Handling and Emplacement Options for Disposal of Radioactive Waste in Deep Boreholes.

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John R.; Hardin, Ernest

    2015-11-01

    Traditional methods cannot be used to handle and emplace radioactive wastes in boreholes up to 16,400 feet (5 km) deep for disposal. This paper describes three systems that can be used for handling and emplacing waste packages in deep borehole: (1) a 2011 reference design that is based on a previous study by Woodward–Clyde in 1983 in which waste packages are assembled into “strings” and lowered using drill pipe; (2) an updated version of the 2011 reference design; and (3) a new concept in which individual waste packages would be lowered to depth using a wireline. Emplacement on coiled tubing was also considered, but not developed in detail. The systems described here are currently designed for U.S. Department of Energy-owned high-level waste (HLW) including the Cesium- 137/Strontium-90 capsules from the Hanford Facility and bulk granular HLW from fuel processing in Idaho.

  7. Eruption and emplacement dynamics of a thick trachytic lava flow of the Sancy volcano (France)

    Science.gov (United States)

    Latutrie, Benjamin; Harris, Andrew; Médard, Etienne; Gurioli, Lucia

    2017-01-01

    A 70-m-thick, 2200-m-long (51 × 106 m3) trachytic lava flow unit underlies the Puy de Cliergue (Mt. Dore, France). Excellent exposure along a 400-m-long and 60- to 85-m-high section allows the flow interior to be accessed on two sides of a glacial valley that cuts through the unit. We completed an integrated morphological, structural, textural, and chemical analysis of the unit to gain insights into eruption and flow processes during emplacement of this thick silicic lava flow, so as to elucidate the chamber and flow dynamic processed that operate during the emplacement of such systems. The unit is characterized by an inverse chemical stratification, where there is primitive lava beneath the evolved lava. The interior is plug dominated with a thin basal shear zone overlying a thick basal breccia, with ramping affecting the entire flow thickness. To understand these characteristics, we propose an eruption model that first involves processes operating in the magma chamber whereby a primitive melt is injected into an evolved magma to create a mixed zone at the chamber base. The eruption triggered by this event first emplaced a trachytic dome, into which banded lava from the chamber base was injected. Subsequent endogenous dome growth led to flow down the shallow slope to the east on which the highly viscous (1012 Pa s) coulée was emplaced. The flow likely moved extremely slowly, being emplaced over a period of 4-10 years in a glacial manner, where a thick (>60-m) plug slid over a thin (5-m-thick) basal shear zone. Excellent exposure means that the Puy de Cliergue complex can be viewed as a case type location for understanding and defining the eruption and emplacement of thick, high-viscosity, silicic lava flow systems.

  8. Thermal barrier coating materials

    Directory of Open Access Journals (Sweden)

    David R. Clarke

    2005-06-01

    Full Text Available Improved thermal barrier coatings (TBCs will enable future gas turbines to operate at higher gas temperatures. Considerable effort is being invested, therefore, in identifying new materials with even better performance than the current industry standard, yttria-stabilized zirconia (YSZ. We review recent progress and suggest that an integrated strategy of experiment, intuitive arguments based on crystallography, and simulation may lead most rapidly to the development of new TBC materials.

  9. Lack of experience-mediated differences in the immunohistochemical expression of blood-brain barrier markers (EBA and GluT-1) during the postnatal development of the rat visual cortex.

    Science.gov (United States)

    Argandoña, Enrike G; Bengoetxea, Harkaitz; Lafuente, José V

    2005-05-12

    The development of the cortical vascular tree depends on functional development. External inputs are an essential requirement in the modeling of the visual cortex, mainly during the critical period, when congruous blood supply is needed. The blood brain barrier (BBB) function regulates the passage of substances between the blood and the brain parenchyma, which is one of the main differential features of central nervous system (CNS) microvessels. The endothelial barrier antigen (EBA) has been reported as a specific marker for the BBB physiological function in rats. We studied the postnatal development of EBA expression in the visual cortex of rats reared under opposite paradigms of visual experience, e.g., standard laboratory conditions, dark rearing, and enriched environment at 14, 21, 28, 35, 42, 49, 56, and 63 days postnatal (dpn). Parallel sections were immunohistochemically processed for endothelial barrier antigen (EBA) and glucose transporter-1 (GluT-1). Total vasculature was quantified by Lycopersicon esculentum (LEA) lectin histochemistry. No differences in EBA expression were found between groups, although quantitative differences were recorded paralleling differences in vascular density. Paradoxically, there was no expression in certain cortical vessels which were GluT-1 immunopositive and positivity was consistent in non-barrier areas such as the pineal gland. These findings were completely independent of age or experimental conditions. Therefore, the role of the EBA antigen in the BBB remains unclear: it has been undeniably linked to vascular permeability, but its presence in non-barrier vessels suggests another vascular function. Although visual experience modifies vascular density in the visual cortex, it has not been shown to have an influence on the maturation of the BBB function.

  10. Employment and Adults Who Are Deaf or Hard of Hearing: Current Status and Experiences of Barriers, Accommodations, and Stress in the Workplace.

    Science.gov (United States)

    Punch, Renée

    2016-01-01

    In an integrative review of the literature covering the period 2004-2016, the author presents a current picture of the situation of people who are deaf or hard of hearing (DHH) relative to employment and careers-particularly the barriers, facilitators, and stress levels experienced by working DHH adults. First, an overview is provided of findings from recent reports on employment outcomes for people who are DHH. Second, the author reviews the literature on employment and workplace barriers, facilitators, and accommodations for people who are DHH, and relates findings about DHH people's workplace-related stress and fatigue levels and the associated issues of job demand, job control, and social support in the workplace. The article concludes with a discussion of the implications of these findings, in particular the ways in which barriers to full participation of DHH people in the labor market can be addressed.

  11. A comprehensive review of the barriers and promoters health workers experience in delivering prevention of vertical transmission of HIV services in sub-Saharan Africa.

    Science.gov (United States)

    Schuster, Roseanne C; McMahon, Devon E; Young, Sera L

    2016-01-01

    Despite significant biomedical and policy advances, 199,000 infants and young children in sub-Saharan Africa (SSA) became infected with HIV in 2013, indicating challenges to implementation of these advances. To understand the nature of these challenges, we sought to (1) characterize the barriers and facilitators that health workers encountered delivering prevention of vertical transmission of HIV (PVT) services in SSA and (2) evaluate the use of theory to guide PVT service delivery. The PubMed and CINAHL databases were searched using keywords barriers, facilitators, HIV, prevention of vertical transmission of HIV, health workers, and their synonyms to identify relevant studies. Barriers and facilitators were coded at ecological levels according to the Determinants of Performance framework. Factors in this framework were then classified as affecting motivation, opportunity, or ability, per the Motivation-Opportunity-Ability (MOA) framework in order to evaluate domains of health worker performance within each ecological level. We found that the most frequently reported challenges occurred within the health facility level and spanned all three MOA domains. Barriers reported in 30% or more of studies from most proximal to distal included those affecting health worker motivation (stress, burnout, depression), patient opportunity (stigma), work opportunity (poor referral systems), health facility opportunity (overburdened workload, lack of supplies), and health facility ability (inadequate PVT training, inconsistent breastfeeding messages). Facilitators were reported in lower frequencies than barriers and tended to be resolutions to challenges (e.g., quality supervision, consistent supplies) or responses to an intervention (e.g., record systems and infrastructure improvements). The majority of studies did not use theory to guide study design or implementation. Interventions addressing health workers' multiple ecological levels of interactions, particularly the health

  12. Feasibility study of tank leakage mitigation using subsurface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Treat, R.L.; Peters, B.B.; Cameron, R.J.; McCormak, W.D.; Trenkler, T.; Walters, M.F. [Ensearch Environmental, Inc. (United States); Rouse, J.K.; McLaughlin, T.J. [Bovay Northwest, Inc., Richland, WA (United States); Cruse, J.M. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-09-21

    The US Department of Energy (DOE) has established the Tank Waste Remediation System (TWRS) to satisfy manage and dispose of the waste currently stored in the underground storage tanks. The retrieval element of TWRS includes a work scope to develop subsurface impermeable barriers beneath SSTs. The barriers could serve as a means to contain leakage that may result from waste retrieval operations and could also support site closure activities by facilitating cleanup. Three types of subsurface barrier systems have emerged for further consideration: (1) chemical grout, (2) freeze walls, and (3) desiccant, represented in this feasibility study as a circulating air barrier. This report contains analyses of the costs and relative risks associated with combinations retrieval technologies and barrier technologies that from 14 alternatives. Eight of the alternatives include the use of subsurface barriers; the remaining six nonbarrier alternative are included in order to compare the costs, relative risks and other values of retrieval with subsurface barriers. Each alternative includes various combinations of technologies that can impact the risks associated with future contamination of the groundwater beneath the Hanford Site to varying degrees. Other potential risks associated with these alternatives, such as those related to accidents and airborne contamination resulting from retrieval and barrier emplacement operations, are not quantitatively evaluated in this report.

  13. Rapid emplacement of young oceanic lithosphere: argon geochronology of the oman ophiolite.

    Science.gov (United States)

    Hacker, B R

    1994-09-01

    (40)Ar/(39)Ar dates of emplacement-related metamorphic rocks beneath the Samail ophiolite in Oman show that cooling to lithosphere must have been adjacent to the ophiolite during spreading and then been thrust beneath the ophiolite almost immediately afterward.

  14. The emplacement of pahoehoe lavas on Kilauea and in the Deccan Traps

    Indian Academy of Sciences (India)

    H C Sheth

    2006-12-01

    There is a growing interest in deciphering the emplacement and environmental impact of flood basalt provinces such as the Deccan, India. Observations of active volcanism lead to meaningful interpretations of now-extinct volcanic systems. Here, I illustrate and discuss the morphology and emplacement of the modern and active lava flows of Kilauea volcano in Hawaii, and based on them, interpret the compound pahoehoe lavas of the Deccan Traps. The latter are vastly larger (areally extensive and voluminous) than Kilauea flows, and yet, their internal architecture is the same as that of Kilauea flows, and even the sizes of individual flow units often identical. Many or most compound flows of the Deccan Traps were emplaced in a gentle, effusive, Kilauea-like fashion. Bulk eruption rates for the Deccan province are unknown, and were probably high, but the local eruption rates of the compound flows were no larger than Kilauea’s. Large (≥ 1000 km3) individual compound pahoehoe flows in the Deccan could have been emplaced at Kilauea-like local eruption rates (1 m3/sec per metre length of fissure) in a decade or less, given fissures of sufficient length (tens of kilometres), now exposed as dyke swarms in the province.

  15. EVALUATION OF RISKS AND WASTE CHARACTERIZATION REQUIREMENTS FOR THE TRANSURANIC WASTE EMPLACED IN WIPP DURING 1999

    Energy Technology Data Exchange (ETDEWEB)

    Channell, J.K.; Walker, B.A.

    2000-05-01

    Specifically this report: 1. Compares requirements of the WAP that are pertinent from a technical viewpoint with the WIPP pre-Permit waste characterization program, 2. Presents the results of a risk analysis of the currently emplaced wastes. Expected and bounding risks from routine operations and possible accidents are evaluated; and 3. Provides conclusions and recommendations.

  16. Palaeomagnetic Emplacement Temperature Determinations of Pyroclastic and Volcaniclastic Deposits in Southern African Kimberlite Pipes

    Science.gov (United States)

    Fontana, G.; Mac Niocaill, C.; Brown, R.; Sparks, R. S.; Matthew, F.; Gernon, T. M.

    2009-12-01

    Kimberlites are complex, ultramafic and diamond-bearing volcanic rocks preserved in volcanic pipes, dykes and craters. The formation of kimberlite pipes is a strongly debated issue and two principal theories have been proposed to explain pipe formation: (1) the explosive degassing of magma, and (2) the interaction of rising magma with groundwater (phreatomagmatism). Progressive thermal demagnetization studies are a powerful tool for determining the emplacement temperatures of ancient volcanic deposits and we present the first application of such techniques to kimberlite deposits. Lithic clasts were sampled from a variety of lithofacies, from three pipes for which the internal geology is well constrained (A/K1 pipe, Orapa Mine, Botswana and the K1 and K2 pipes, Venetia Mine, South Africa). The sampled deposits included massive and layered vent-filling breccias with varying abundances of lithic inclusions and layered crater-filling pyroclastic deposits, talus breccias and volcaniclastic breccias. Lithic clasts sampled from layered and massive vent-filling pyroclastic deposits in A/K1 were emplaced at >590° C. Results from K1 and K2 provide a maximum emplacement temperature limit for vent-filling breccias of 420-460° C; and constrain equilibrium deposit temperatures at 300-340° C. Crater-filling volcaniclastic kimberlite breccias and talus deposits from A/K1 were emplaced at ambient temperatures, consistent with infilling of the pipe by post-eruption epiclastic processes. Identified within the epiclastic crater-fill succession is a laterally extensive 15-20 metre thick kimberlite pyroclastic flow deposit emplaced at temperatures of 220-440° C. It overlies the post-eruption epiclastic units and is considered an extraneous pyroclastic kimberlite deposit erupted from another kimberlite vent. The results provide important constraints on kimberlite emplacement mechanisms and eruption dynamics. Emplacement temperatures of >590°C for pipe-filling pyroclastic deposits

  17. Barriers and facilitators to evidence based care of type 2 diabetes patients : experiences of general practitioners participating to a quality improvement program

    NARCIS (Netherlands)

    Goderis, G.; Borgermans, L.D.A.; Mathieu, C.; Broeke, C. Van Den; Hannes, K.; Heyrman, J.; Grol, R.P.T.M.

    2009-01-01

    ABSTRACT: OBJECTIVE: To evaluate the barriers and facilitators to high-quality diabetes care as experienced by general practitioners (GPs) who participated in an 18-month quality improvement program (QIP). This QIP was implemented to promote compliance with international guidelines. METHODS: Twenty

  18. Barriers to the provision of high-quality palliative care for people with dementia in England: a qualitative study of professionals' experiences

    NARCIS (Netherlands)

    Davies, N.; Maio, L.; Vedavanam, K.; Manthorpe, J.; Vernooij-Dassen, M.J.F.J.; Iliffe, S.

    2014-01-01

    Approaches to palliative care that were originally developed for people with cancer are now being adopted for people with dementia, as a response to many reports of poor-quality care for people with dementia at the end of life. This study explored perceived barriers to the delivery of high-quality p

  19. Ultradeformable lipid vesicles can penetrate the skin and other semi-permeable barriers unfragmented. Evidence from double label CLSM experiments and direct size measurements.

    Science.gov (United States)

    Cevc, Gregor; Schätzlein, Andreas; Richardsen, Holger

    2002-08-19

    The stability of various aggregates in the form of lipid bilayer vesicles was tested by three different methods before and after crossing different semi-permeable barriers. First, polymer membranes with pores significantly smaller than the average aggregate diameter were used as the skin barrier model; dynamic light scattering was employed to monitor vesicle size changes after barrier passage for several lipid mixtures with different bilayer elasticities. This revealed that vesicles must adapt their size and/or shape, dependent on bilayer stability and elasto-mechanics, to overcome an otherwise confining pore. For the mixed lipid aggregates with highly flexible bilayers (Transfersomes), the change is transient and only involves vesicle shape and volume adaptation. The constancy of ultradeformable vesicle size before and after pores penetration proves this. This is remarkable in light of the very strong aggregate deformation during an enforced barrier passage. Simple phosphatidylcholine vesicles, with less flexible bilayers, lack such capability and stability. Conventional liposomes are therefore fractured during transport through a semi-permeable barrier; as reported by other researchers, liposomes are fragmented to the size of a narrow pore if sufficient pressure is applied across the barrier; otherwise, liposomes clog the pores. The precise outcome depends on trans-barrier flux and/or on relative vesicle vs. pore size. Lipid vesicles applied on the skin behave accordingly. Mixed lipid vesicles penetrate the skin if they are sufficiently deformable. If this is the case, they cross inter-cellular constrictions in the organ without significant composition or size modification. To prove this, we labelled vesicles with two different fluorescent markers and applied the suspension on intact murine skin without occlusion. The confocal laser scanning microscopy (CLSM) of the skin then revealed a practically indistinguishable distribution of both labels in the stratum

  20. Buffered and unbuffered dike emplacement on Earth and Venus - Implications for magma reservoir size, depth, and rate of magma replenishment

    Science.gov (United States)

    Parfitt, E. A.; Head, J. W., III

    1993-01-01

    Models of the emplacement of lateral dikes from magma chambers under constant (buffered) driving pressure conditions and declining (unbuffered) driving pressure conditions indicate that the two pressure scenarios lead to distinctly different styles of dike emplacement. In the unbuffered case, the lengths and widths of laterally emplaced dikes will be severely limited and the dike lengths will be highly dependent on chamber size; this dependence suggests that average dike length can be used to infer the dimensions of the source magma reservoir. On Earth, the characteristics of many mafic-dike swarms suggest that they were emplaced in buffered conditions (e.g., the Mackenzie dike swarm in Canada and some dikes within the Scottish Tertiary). On Venus, the distinctive radial fractures and graben surrounding circular to oval features and edifices on many size scales and extending for hundreds to over a thousand km are candidates for dike emplacement in buffered conditions.

  1. New barrier fluids for subsurface containment of contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Moridis, G.J.; Persoff, P.; Holman, H.Y.; Muller, S.J.; Pruess, K.; Radke, C.J.

    1993-10-01

    In some situations, containment of contaminants in the subsurface may be preferable to removal or treatment in situ. In these cases, it maybe possible to form barriers by injecting fluids (grouts) that set in place and reduce the formation permeability. This paper reports laboratory work to develop two types of fluids for this application: colloidal silica (CS) and polysiloxane (PSX). Falling-head permeameter tests of grouted Hanford sand, lasting 50 days, showed hydraulic conductivities of order 10{sup -7} cm/sec for these two materials. Low initial viscosity of the grout is necessary to permit injection without causing fracturing or surface uplift. Experiments with crosslinked polysiloxanes showed that they could be diluted to achieve adequately low viscosity without losing their ability to cure. Control of the gel time is important for grout emplacement. Gel time of CS grouts increased with increasing pH (above 6.5) and with decreasing ionic strength. Salt solutions were added to the colloid-to increase the ionic strength and control gel time. When injected into Hanford sand, the CS grout gelled much more quickly than the same formula without sand. This effect results from salinity that is present in pore water and from multi-valent ions that are desorbed from clays and ion-exchanged for mono-valent ions in the grout. Ion-exchange experiments showed that most of the multi-valent ions could be removed-by flushing the sand with 15 PV of 4% NaCl and sand treated in this manner did not accelerate the gelling of the grout. When grout is injected into unsaturated soil it slumps, leaving the soil only partially saturated and achieving less permeability reduction upon gelling. Multiple injections of CS grout in 1-D sand columns demonstrated that by accumulating the residual gelled grout saturations from several injections, low permeability can be achieved.

  2. Thermochronology of the Cornubian batholith in southwest England: Implications for pluton emplacement and protracted hydrothermal mineralization

    Science.gov (United States)

    Chesley, J.T.; Halliday, A.N.; Snee, L.W.; Mezger, K.; Shepherd, T.J.; Scrivener, R.C.

    1993-01-01

    The metalliferous ore deposits of southwest England are associated with biotite-muscovite granites that intruded upper Paleozoic sediments and volcanic rocks at the end of the Hercynian Orogeny. The hydrothermal mineralization can be subdivided into four stages: 1. (1) exoskarns 2. (2) high-temperature tin and tungsten oxide-bearing sheeted greisen bordered veins and Sn-bearing tourmaline veins and breccias 3. (3) polymetallic quartz-tourmaline-chlorite-sulfide-fluorite-bearing fissure veins, which represent the main episode of economic mineralization 4. (4) late-stage, low-temperature polymetallic fluorite veins. U-Pb dating of monazite and xenotime and 40Ar 39Ar dating of muscovite were used to determine emplacement ages and cooling times for individual plutons within the Cornubian batholith, as well as separate intrusive phases within the plutons. In addition, 40Ar 39Ar ages from hornblende and secondary muscovite and Sm-Nd isochron ages from fluorite were employed to determine the relationship between pluton emplacement and different stages of mineralization. The U-Pb ages indicate that granite magmatism was protracted from ~300 Ma down to ~275 Ma with no evidence of a major hiatus. There is no systematic relation between the age of a pluton and its location within the batholith. The U-Pb ages for separate granite phases within a single pluton are resolvable and indicate that magma emplacement within individual plutons occurred over periods of as much as 4.5 myrs. Felsic porphyry dike emplacement was coeval with plutonism, but continued to ~270 Ma. The geochronologic data suggest that the Cornubian batholith originated from repeated melting events over 30 myrs and was formed by a series of small coalescing granitic bodies. Cooling rates of the main plutons are unrelated to emplacement age, but decrease from the southwest to the northeast from ~210??C myr-1 to ~60??C myr-1 with a mean of 100??C myr-1. These slow cooling rates appear to reflect the addition of

  3. Early experiences on the feasibility, acceptability, and use of malaria rapid diagnostic tests at peripheral health centres in Uganda-insights into some barriers and facilitators

    Directory of Open Access Journals (Sweden)

    Asiimwe Caroline

    2012-01-01

    Full Text Available Abstract Background While feasibility of new health technologies in well-resourced healthcare settings is extensively documented, it is largely unknown in low-resourced settings. Uganda's decision to deploy and scale up malaria rapid diagnostic tests (mRDTs in public health facilities and at the community level provides a useful entry point for documenting field experience, acceptance, and predictive variables for technology acceptance and use. These findings are important in informing implementation of new health technologies, plans, and budgets in low-resourced national disease control programmes. Methods A cross-sectional qualitative descriptive study at 21 health centres in Uganda was undertaken in 2007 to elucidate the barriers and facilitators in the introduction of mRDTs as a new diagnostic technology at lower-level health facilities. Pre-tested interview questionnaires were administered through pre-structured patient exit interviews and semi-structured health worker interviews to gain an understanding of the response to this implementation. A conceptual framework on technology acceptance and use was adapted for this study and used to prepare the questionnaires. Thematic analysis was used to generate themes from the data. Results A total of 52 of 57 health workers (92% reported a belief that a positive mRDT result was true, although only 41 of 57 (64% believed that treatment with anti-malarials was justified for every positive mRDT case. Of the same health workers, only 49% believed that a negative mRDT result was truly negative. Factors linked to these findings were related to mRDT acceptance and use, including the design and characteristics of the device, availability and quality of mRDT ancillary supplies, health worker capacity to investigate febrile cases testing negative with the device and provide appropriate treatment, availability of effective malaria treatments, reliability of the health commodity supply chain, existing national

  4. Barriers to leisure participation for people with dementia and their carers: An exploratory analysis of carer and people with dementia's experiences.

    Science.gov (United States)

    Innes, Anthea; Page, Stephen J; Cutler, Clare

    2016-11-01

    Leisure has emerged as a prominent research theme within the growing body of knowledge on dementia, with a focus on physical activity. Yet participation in any form of leisure presupposes an ability to freely choose to partake in activities and to negotiate one's way around key barriers. In the case of dementia, the ability to undertake leisure activities is subject to a greater range of barriers, structured in a hierarchical manner that contributes to social exclusion if not addressed. This study based on focus groups with people with dementia and their family members conducted in Dorset, UK illustrates a range of barriers to leisure participation. How to create or maintain leisure opportunities for those living with dementia where households affected by dementia do not adopt avoidance behaviour, compounding a sense of isolation and exclusion is a challenge. Leisure can be an important strategy framed as a form of resistance to the social disabilities experienced by those living with dementia and it is potentially isolating impact.

  5. Emplacement of the Jurassic Mirdita ophiolites (southern Albania): evidence from associated clastic and carbonate sediments

    Science.gov (United States)

    Robertson, Alastair H. F.; Ionescu, Corina; Hoeck, Volker; Koller, Friedrich; Onuzi, Kujtim; Bucur, Ioan I.; Ghega, Dashamir

    2012-09-01

    Sedimentology can shed light on the emplacement of oceanic lithosphere (i.e. ophiolites) onto continental crust and post-emplacement settings. An example chosen here is the well-exposed Jurassic Mirdita ophiolite in southern Albania. Successions studied in five different ophiolitic massifs (Voskopoja, Luniku, Shpati, Rehove and Morava) document variable depositional processes and palaeoenvironments in the light of evidence from comparable settings elsewhere (e.g. N Albania; N Greece). Ophiolitic extrusive rocks (pillow basalts and lava breccias) locally retain an intact cover of oceanic radiolarian chert (in the Shpati massif). Elsewhere, ophiolite-derived clastics typically overlie basaltic extrusives or ultramafic rocks directly. The oldest dated sediments are calpionellid- and ammonite-bearing pelagic carbonates of latest (?) Jurassic-Berrasian age. Similar calpionellid limestones elsewhere (N Albania; N Greece) post-date the regional ophiolite emplacement. At one locality in S Albania (Voskopoja), calpionellid limestones are gradationally underlain by thick ophiolite-derived breccias (containing both ultramafic and mafic clasts) that were derived by mass wasting of subaqueous fault scarps during or soon after the latest stages of ophiolite emplacement. An intercalation of serpentinite-rich debris flows at this locality is indicative of mobilisation of hydrated oceanic ultramafic rocks. Some of the ophiolite-derived conglomerates (e.g. Shpati massif) include well-rounded serpentinite and basalt clasts suggestive of a high-energy, shallow-water origin. The Berriasian pelagic limestones (at Voskopoja) experienced reworking and slumping probably related to shallowing and a switch to neritic deposition. Mixed ophiolite-derived clastic and neritic carbonate sediments accumulated later, during the Early Cretaceous (mainly Barremian-Aptian) in variable deltaic, lagoonal and shallow-marine settings. These sediments were influenced by local tectonics or eustatic sea

  6. Lunar mare deposits associated with the Orientale impact basin: New insights into mineralogy, history, mode of emplacement, and relation to Orientale Basin evolution from Moon Mineralogy Mapper (M3) data from Chandrayaan-1

    Science.gov (United States)

    Whitten, J.; Head, J.W.; Staid, M.; Pieters, C.M.; Mustard, J.; Clark, R.; Nettles, J.; Klima, R.L.; Taylor, L.

    2011-01-01

    Moon Mineralogy Mapper (M3) image and spectral reflectance data are combined to analyze mare basalt units in and adjacent to the Orientale multiring impact basin. Models are assessed for the relationships between basin formation and mare basalt emplacement. Mare basalt emplacement on the western nearside limb began prior to the Orientale event as evidenced by the presence of cryptomaria. The earliest post-Orientale-event mare basalt emplacement occurred in the center of the basin (Mare Orientale) and postdated the formation of the Orientale Basin by about 60-100 Ma. Over the next several hundred million years, basalt patches were emplaced first along the base of the Outer Rook ring (Lacus Veris) and then along the base of the Cordillera ring (Lacus Autumni), with some overlap in ages. The latest basalt patches are as young as some of the youngest basalt deposits on the lunar nearside. M3 data show several previously undetected mare patches on the southwestern margins of the basin interior. Regardless, the previously documented increase in mare abundance from the southwest toward the northeast is still prominent. We attribute this to crustal and lithospheric trends moving from the farside to the nearside, with correspondingly shallower density and thermal barriers to basaltic magma ascent and eruption toward the nearside. The wide range of model ages for Orientale mare deposits (3.70-1.66 Ga) mirrors the range of nearside mare ages, indicating that the small amount of mare fill in Orientale is not due to early cessation of mare emplacement but rather to limited volumes of extrusion for each phase during the entire period of nearside mare basalt volcanism. This suggests that nearside and farside source regions may be similar but that other factors, such as thermal and crustal thickness barriers to magma ascent and eruption, may be determining the abundance of surface deposits on the limbs and farside. The sequence, timing, and elevation of mare basalt deposits

  7. Dyke emplacement and propagation: a new laboratory approach

    Science.gov (United States)

    Bakker, R.; Benson, P.; Vinciguerra, S.

    2013-12-01

    It is well known that magma ascends trough the crust by the process of dyking. During dyke movement crustal rocks, specifically the volcano's basement rocks, fracture due to the stress imposed by the ascending magma, thus providing conduits for magma transport. Dykes are frequently seen in the field and have been reproduced via numerical and analogue studies. However, a number of assumptions regarding rock mechanical behavior frequently has to be made as such data are very hard to directly measure at the pressure/temperature conditions of interest: high temperatures at relatively shallow depths. Such data are key to simulating the magma intrusion dynamics through the lithologies that underlie the volcanic edifice. To bridge this gap, we have performed a suite of rock deformation experiments in both compressive and tensile regimes, using a Paterson-type triaxial apparatus on representative lithologies present in the basement of Mt. Etna. In the compressive regime, we find that sedimentary rocks present at a depth of aproximately 2 km show a B/D transition at around 300 degC and significant weakening with temperatures exceeding 400 degC. Volcanic rocks (basalt) shows a significant change in deformation behavior only at temperatures exceeding 800 degC. Such a large contrast in mechanical properties could be favorable for dyke deflection or dyke arrest. However, in the tensile regime, it remains a significant technical challenge to precisely reproduce the conditions of dyking in the lab. As a starting point, we are now testing an analogue material to replace the magma to avoid such high temperatures, relying of maintaining similar temperature/viscosity ratios between magma/country rock in the laboratory and the field. We chose PMMA (a.k.a. plexiglass) for this task as it displays a large range in viscosities (log(visc)range = 10 - 1) with temperatures between 100 and 300 degC, making it an excellent analogue material. In addition PMMA solidifies after the sample cools

  8. THE EXPERIMENT RESEARCH ON THE IMPACT ON INHABITANTS' ENVIRONMENT OF HIGH SPEED RAILWAY SOUND BARRIERS%高速铁路声屏障对居民环境影响的试验研究

    Institute of Scientific and Technical Information of China (English)

    杨明亮; 丁渭平; 徐小程; 李智; 宋睿

    2012-01-01

    Three kinds of structures of the high speed railway sound barriers are taken as the research object.Combining with the noise limit in "Acoustic Environment Quality Standard"(GB 3096—2008),the evaluation of the impact on residents' environment of high speed railway sound barriers is carried out through measuring the eight points sound pressure values when the high-speed train is passing the measurement set and calculating equivalent continuous A-weight sound pressure level of every measurement point and the sound insulation amount of sound barriers.Three conclusions are obtained through experiment and calculating.Firstly,sound barriers help improving the inhabitants' environment;secondly,the sound pressure level of environment noise around high speed railway is higher than the national standard limits because of the sound insulation amount of the three test sound barriers is too small compared with the general design requirements(20~25dB);lastly,sound barriers should be improved towards the direction of increasing the sound insulation amount of middle and low frequency noise.%以3种结构的高速铁路声屏障为研究对象,测量了高速列车通过有声、无声屏障两种状态下8个测点的声压值,并计算各测点等效连续A计权声压和声屏障的隔声量,结合GB 3096—2008《声环境质量标准》中规定的环境噪声限值进行声屏障结构对高速铁路周边居民的声环境影响评价。试验分析结果表明:声屏障不同程度改善了居民的声环境;由于试验所用的3种结构的声屏障隔声量离一般设计要求(20~25dB)相差太远,使得高速铁路周边环境噪声高于国家标准规定限值;声屏障结构改进应着力提高中低频噪声的隔声量。

  9. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    R. Jarek

    2004-11-23

    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

  10. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    G.H. Nieder-Westermann

    2005-04-07

    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

  11. Fluid flow and reactive transport around potential nuclear waste emplacement tunnels at Yucca Mountain, Nevada

    OpenAIRE

    Spycher, N.F.; Sonnenthal, E. L.; Apps, J.A.

    2002-01-01

    The evolution of fluid chemistry and mineral alteration around a potential waste emplacement tunnel (drift) is evaluated using numerical modeling. The model considers the flow of water, gas, and heat, plus reactions between minerals, CO2 gas, and aqueous species, and porosity permeability-capillary pressure coupling for a dual permeability (fractures and matrix) medium. Two possible operating temperature modes are investigated: a "high-temperature" case with temperatures exceeding the bo...

  12. Emplacement temperatures of pyroclastic and volcaniclastic deposits in kimberlite pipes in southern Africa

    Science.gov (United States)

    Fontana, Giovanni; Mac Niocaill, Conall; Brown, Richard J.; Sparks, R. Stephen J.; Field, Matthew

    2011-10-01

    Palaeomagnetic techniques for estimating the emplacement temperatures of volcanic deposits have been applied to pyroclastic and volcaniclastic deposits in kimberlite pipes in southern Africa. Lithic clasts were sampled from a variety of lithofacies from three pipes for which the internal geology is well constrained (the Cretaceous A/K1 pipe, Orapa Mine, Botswana, and the Cambrian K1 and K2 pipes, Venetia Mine, South Africa). The sampled deposits included massive and layered vent-filling breccias with varying abundances of lithic inclusions, layered crater-filling pyroclastic deposits, talus breccias and volcaniclastic breccias. Basalt lithic clasts in the layered and massive vent-filling pyroclastic deposits in the A/K1 pipe at Orapa were emplaced at >570°C, in the pyroclastic crater-filling deposits at 200-440°C and in crater-filling talus breccias and volcaniclastic breccias at 560°C, although the interpretation of these results is hampered by the presence of Mesozoic magnetic overprints. These temperatures are comparable to the estimated emplacement temperatures of other kimberlite deposits and fall within the proposed stability field for common interstitial matrix mineral assemblages within vent-filling volcaniclastic kimberlites. The temperatures are also comparable to those obtained for pyroclastic deposits in other, silicic, volcanic systems. Because the lithic content of the studied deposits is 10-30%, the initial bulk temperature of the pyroclastic mixture of cold lithic clasts and juvenile kimberlite magma could have been 300-400°C hotter than the palaeomagnetic estimates. Together with the discovery of welded and agglutinated juvenile pyroclasts in some pyroclastic kimberlites, the palaeomagnetic results indicate that there are examples of kimberlites where phreatomagmatism did not play a major role in the generation of the pyroclastic deposits. This study indicates that palaeomagnetic methods can successfully distinguish differences in the

  13. Emplacement temperatures of pyroclastic and volcaniclastic deposits in kimberlite pipes in southern Africa

    OpenAIRE

    Fontana, Giovanni; Mac Niocaill, Conall; Brown, Richard J.; Sparks, R. Stephen J.; Field, Matthew

    2011-01-01

    Palaeomagnetic techniques for estimating the emplacement temperatures of volcanic deposits have been applied to pyroclastic and volcaniclastic deposits in kimberlite pipes in southern Africa. Lithic clasts were sampled from a variety of lithofacies from three pipes for which the internal geology is well constrained (the Cretaceous A/K1 pipe, Orapa Mine, Botswana, and the Cambrian K1 and K2 pipes, Venetia Mine, South Africa). The sampled deposits included massive and layered vent-filling brecc...

  14. Emplacing, Firing, and March Ordering an M109A1 Howitzer: Tasks and Task Times

    Science.gov (United States)

    1981-06-01

    1. Opens rear cab doors and dismounts. 2. Removes left spade strut safety pin . Releases left locking latch and lowers spade to ground. 3. Procures...closes hull door for emplacement of the spades. 2. Removes right spade strut safety pin . Removes right locking latch and lowers spade to ground. 3...lifts the right spade into the travel position. Replaces right spade strut safety pin . 4. Takes post. NUMBER 3 CANNONEER 1. Insures that projectiles

  15. Logistics Modeling of Emplacement Rate and Duration of Operations for Generic Geologic Repository Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Kalinina, Elena Arkadievna; Hardin, Ernest

    2015-11-01

    This study identified potential geologic repository concepts for disposal of spent nuclear fuel (SNF) and (2) evaluated the achievable repository waste emplacement rate and the time required to complete the disposal for these concepts. Total repository capacity is assumed to be approximately 140,000 MT of spent fuel. The results of this study provide an important input for the rough-order-of-magnitude (ROM) disposal cost analysis. The disposal concepts cover three major categories of host geologic media: crystalline or hard rock, salt, and argillaceous rock. Four waste package sizes are considered: 4PWR/9BWR; 12PWR/21BWR; 21PWR/44BWR, and dual purpose canisters (DPCs). The DPC concepts assume that the existing canisters will be sealed into disposal overpacks for direct disposal. Each concept assumes one of the following emplacement power limits for either emplacement or repository closure: 1.7 kW; 2.2 kW; 5.5 kW; 10 kW; 11.5 kW, and 18 kW.

  16. Transport and Emplacement of the 15.4 Ma Rhyolitic Ignimbrites from Gutai Mts., Eastern Carpathians

    Directory of Open Access Journals (Sweden)

    Alexandrina Fulop

    2002-04-01

    Full Text Available The 15.4 Ma rhyolitic ignimbrites are the first volcanic products from Gutâi Mts. The study of their sedimentary structures reflects the mechanisms involved in the transport and emplacement of the parental flows, essential to inffering the style of eruption and the source evolution and location. Primary sedimentary structures show massive deposits emplaced from mass flows, sequence of units showing the normal coarse-tail grading of the dense clasts and the reverse coarse-tail grading of the pumice clasts. They reflect concentrated laminar flows or dilute, subcritical flows emplaced by progressive aggradation. Secondary sedimentary structures are represented by the eutaxitic texture or welding, cooling textures (columnar jointings, spherulitic textures and gas-escape pipes. They assess the hot state deposition with low degree of fluidization, low cooling rates and gas-retention regime. Secondary sedimentary structures are represented by the eutaxitic texture or welding, cooling textures (columnar jointings, spherulitic textures and gas-escape pipes. They assess the hot state deposition with low degree of fluidization, low cooling rates and gas-retention regime.

  17. Transport and emplacement of ignimbrites and resedimented volcaniclastics from Gutai Mts., Eastern Carpathians, Romania

    Directory of Open Access Journals (Sweden)

    Alexandrina Fülöp

    2004-04-01

    Full Text Available Gutâi Mts. had started to be built up in Middle Miocene, ca. 15.4 Ma ago. A series of explosive events developed starting with a major magmatic explosion and caldera collapse responsible for large volumes of ignimbrites. Successive explosions followed caldera collapse triggering a series of pyroclastic currents that underwent subsequent reworking. Mass flow has been the main transport mechanism recorded by the sedimentary structures of either ignimbrites or post-ignimbrites volcaniclastics. Multiple ignimbrite units resulted from subaerial mass flows, successively emplaced by progressive aggradation from the basal layer of a density-stratified pyroclastic current. The overlying sequence is composed of different volcaniclastics of pyroclastic origin interlayered with mudstones. They preserve the original composition of ignimbrites, but lack the evidence of hot-state deposition, recording the emplacement from more or less dilute mass flows. A syn-eruptive stage of resedimentation is suggested prior to emplacement in submarine conditions, determined by the transformation of gas-supported pyroclastic currents into water-supported mass flows after transition from subaerial to submarine conditions. The syn-eruptive resedimented volcaniclastics may be correlated with the ignimbrite-type subaerial pyroclastic flows, but they show different degrees of fluidization due to the impact of submarine environment.

  18. Structural pattern and emplacement mechanism of the Neka Valley nappe complex, eastern Alborz, Iran

    Science.gov (United States)

    Nabavi, Seyed Tohid; Rahimi-Chakdel, Aziz; Khademi, Mohsen

    2016-12-01

    The Neka Valley nappe complex is exposed in the south of Gorgan County in the eastern Alborz fold-and-thrust belt. We use the results of a regional survey of the structural data and their patterns to interpret the mechanisms that emplaced the unmetamorphosed nappes in the foreland fold-and-thrust belt of the Alborz Mountains. Most of the strain magnitudes are low in the study area but increase slightly towards what are probably their proximal ends. Strain ellipsoid is dominantly oblate with XY aligned along and across the belt (or the nappe complex). The average kinematic vorticity number, W k = 0.6 which indicates most of the strain partitioning resulted in a general shear. Most of Flinn's k values and α (the stretch along the shear plane) values are lower than 1. Structural indicators such as orthogonal extensional joints, pinch-and-swell structures, anastomosing cleavages, and listric normal and growth faults developed by push from the rear. Large-scale thrust complexes with opposed-dips such as triangle zones (as well as k and α-values <1) are compatible with the shear flow diverging distally and streamlines expected of the rear compression emplacement mechanism. Together with a later minor brittle deformation, these major ductile strains appears to provide a general model suitable for the emplacement of the nappes studied in a thin-skinned fold-and-thrust belt where the sedimentary cover strata shortened and imbricated in the upper crust.

  19. Field Features And Mode Of Emplacement Of Pegmatites Of Keffi Area North Central Nigeria

    Directory of Open Access Journals (Sweden)

    Tanko

    2015-04-01

    Full Text Available Abstract The Keffi area of North Central Nigeria hosts numerous pegmatite bodies which are related to the surrounding granitic intrusions islocated about 45 km east of the Federal Capital Territory Abuja Nigeria. Petrological investigation of the pegmatites and surrounding host rocks aimed at characterising and understanding field relations and mode of emplacement of the rocks with a view to assess their mineralisation potentials were carried out. From the field observations the pegmatites were characterised into 1 Pelitic schist-amphibolite hosted pegmatites and 2 Granitoids orthogneisses hosted pegmatites and the granites into 1 the Bakin Ayini biotite granites 2 the Angwan Madugu biotite-muscovite granites and 3 the Sabongida biotite-muscovite granites. It is clear that those discordantly emplaced in pelitic schists varied in shape and size with length and width ranging from 400-2000m and 2-20m respectively some are huge isolated sill-like and flat-lying whilst those hosted in orthogneisses are narrow ranging in length 40-1000m and width 1-4m crosscutting and vertically oriented along shear zones which suggest passive emplacement

  20. The role of the geothermal gradient in the emplacement and replenishment of ground ice on Mars

    Science.gov (United States)

    Clifford, Stephen M.

    1993-01-01

    Knowledge of the mechanisms by which ground ice is emplaced, removed, and potentially replenished, are critical to understanding the climatic and hydrologic behavior of water on Mars, as well as the morphologic evolution of its surface. Because of the strong temperature dependence of the saturated vapor pressure of H2O, the atmospheric emplacement or replenishment of ground ice is prohibited below the depth at which crustal temperatures begin to monotonically increase due to geothermal heating. In contrast, the emplacement and replenishment of ground ice from reservoirs of H2O residing deep within the crust can occur by at least three different thermally-driven processes, involving all three phases of water. In this regard, Clifford has discussed how the presence of a geothermal gradient as small as 15 K/km can give rise to a corresponding vapor pressure gradient sufficient to drive the vertical transport of 1 km of water from a reservoir of ground water at depth to the base of the cryosphere every 10(exp 6) - 10(exp 7) years. This abstract expands on this earlier treatment by considering the influence of thermal gradients on the transport of H2O at temperatures below the freezing point.

  1. The ongoing dome emplacement and destruction cyclic process at Popocatépetl volcano, Central Mexico

    Science.gov (United States)

    Gómez-Vazquez, Angel; De la Cruz-Reyna, Servando; Mendoza-Rosas, Ana Teresa

    2016-09-01

    The ongoing eruptive activity of Popocatépetl volcano has been characterized by emplacement and subsequent destruction of a succession of lava domes. Between the onset of the current eruption in 1994 and the time of this submission, 38 episodes of lava dome formation and removal have been identified. Each dome has showed particular features related to the magma extrusion process. Among other manifestations, dome-emplacement events have been usually accompanied by relatively low-intensity, protracted explosions referred to as exhalations. After variable times of residence, emplacements have ended in partial or total destruction of the domes by strong vulcanian explosions that produced sizeable ash plumes, with most of them also ejecting incandescent debris onto the volcano flanks. Here, we present a detailed account for the observed activity related to the domes' growth and destruction, related seismic monitoring signals, and morphological features of the domes based on 19 years of visual observations and image analysis. We then discuss a model for the process of dome growth and destruction and its hazard implications.

  2. AN EVALUATION TO IDENTIFY THE BARRIERS TO THE FEASIBILITY OF URBAN DEVELOPMENT PLANS: FIVE DECADES OF EXPERIENCE IN URBAN PLANNING IN IRAN

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Maghsoodi Tilaki

    2014-01-01

    Full Text Available The rapid urbanization in many developing countries has indicat ed several challenges in different aspects. This is due t o inefficient urban planning ap proaches towards managing the development process. Similar to many other developing count ries, Iran has experienced rapid urbanization in recent decades. Although over the last few decades, urban planning processes have been applied to develop Iranian c ities, urban planning has failed to tackle the challenges facing the cities. This paper s eeks to identify the barriers that have prevented Iranian c ities from achieving the goals of urban planning. The purpose of this paper is to provide a comprehensive review of the curre nt literature on the concept of urban planning and to assess the urban development plan proc ess in Iranian cities. The required data were collected through a review of international theoretical studies, Iranian experimental research and governmental reports. The findings of this study reveal five major barriers to the feasibility of the urban planning process , including the urban plans context, structure of urban pla nning, related law and regulatio ns, public participation, and financial resources.

  3. Research on the Experiment of Overcoming Underwater Barrier in Learning Swimming%克服学游泳闷水障碍的实验研究

    Institute of Scientific and Technical Information of China (English)

    朱鹏

    2013-01-01

    Underwater swimming is an inevitable link in learning swimming, but it hinders very few people's swimming learning for fear of underwater swimming, so the learners must grasp the skill of underwater swimming. Choking the water and failing to hold one's breath is the main reason resulting to underwater barrier. Through blowing balloons and using straws to suck table tennis, the writer attempts to improve the learners' nose and mouth breathing control ability, which can overcome underwater barrier.%  闷水是学游泳必须经历的一关,有很少的一部分人因为害怕闷水阻碍了学游泳的进程,或者说不能学习标准游泳动作,而闷水是求生技能的重要部分,学习求生技能必须掌握闷水。呛水和屏不住气是导致闷水障碍的主要原因,我通过吹气球、吸管吸乒乓球练习,提高他们的鼻腔和口腔的呼吸控制能力,从而克服闷水障碍。

  4. Breaching barriers to collaboration in public spaces

    DEFF Research Database (Denmark)

    Heinemann, Trine; Mitchell, Robb

    2014-01-01

    Technology provoking disparate individuals to collaborate or share experiences in the public space faces a difficult barrier, namely the ordinary social order of urban places. We employed the notion of the breaching experiment to explore how this barrier might be overcome. We analyse responses...... to a set of city center social interventions to reveal four themes: "offering collaboration", "requesting collaboration", "allowing for collaboration" and "making collaboration contextually relevant". Each of these breaching experiments in different ways helps reveal the ordinary social organization...

  5. Numerical models of mantle lithosphere weakening, erosion and delamination induced by melt extraction and emplacement

    Science.gov (United States)

    Wallner, Herbert; Schmeling, Harro

    2016-09-01

    Continental rifting caused by extension and heating from below affects the lithosphere or cratons in various ways. Volcanism and melt intrusions often occur along with thinning, weakening and even breaking lithosphere. Although mechanical necking models of the lithosphere are often applied, the aspects of melting and the implications due to melt transport and emplacement at shallower depths are not well understood. A two-phase flow approach employing melt extraction and shallow emplacement associated with thermal weakening is developed and compared with observations. The results of this comparison indicate the importance of partial melts and an asthenospheric magma source for increasing the rising rate of the lithosphere-asthenosphere boundary during extension. Thermo-mechanical physics of visco-plastic flow is approximated using the Finite Difference method with Eulerian formulation in 2D. The conservation of mass, momentum and energy equations are solved for a multi-component (crust-mantle) and two-phase (melt-matrix) system. Rheology is temperature- and stress-dependent. In consideration of depletion and enrichment melting and solidification are controlled by a simplified linear binary solid solution model. Melt is extracted and emplaced in predefined depth regions (emplacement zones) in the lithospheric mantle and crust. The Compaction Boussinesq Approximation was applied; its validity was tested against the Full Compaction formulation and found fully satisfactory for the case of sublithospheric melting models. A simple model guided by the geodynamic situation of the Rwenzori region typically results in updoming asthenosphere with melt-assisted erosion of the lithosphere's base. Even with a conservative approach for a temperature anomaly melting alone doubles the lithospheric erosion rate in comparison with a model without melting. With melt extraction and intrusion lithospheric erosion and upwelling of the lithosphere-asthenosphere boundary speeds up by a

  6. Geological Disposal of Nuclear Waste: Investigating the Thermo-Hygro-Mechanical-Chemical (THMC) Coupled Processes at the Waste Canister- Bentonite Barrier Interface

    Science.gov (United States)

    Davies, C. W.; Davie, D. C.; Charles, D. A.

    2015-12-01

    Geological disposal of nuclear waste is being increasingly considered to deal with the growing volume of waste resulting from the nuclear legacy of numerous nations. Within the UK there is 650,000 cubic meters of waste safely stored and managed in near-surface interim facilities but with no conclusive permanent disposal route. A Geological Disposal Facility with incorporated Engineered Barrier Systems are currently being considered as a permanent waste management solution (Fig.1). This research focuses on the EBS bentonite buffer/waste canister interface, and experimentally replicates key environmental phases that would occur after canister emplacement. This progresses understanding of the temporal evolution of the EBS and the associated impact on its engineering, mineralogical and physicochemical state and considers any consequences for the EBS safety functions of containment and isolation. Correlation of engineering properties to the physicochemical state is the focus of this research. Changes to geotechnical properties such as Atterberg limits, swelling pressure and swelling kinetics are measured after laboratory exposure to THMC variables from interface and batch experiments. Factors affecting the barrier, post closure, include corrosion product interaction, precipitation of silica, near-field chemical environment, groundwater salinity and temperature. Results show that increasing groundwater salinity has a direct impact on the buffer, reducing swelling capacity and plasticity index by up to 80%. Similarly, thermal loading reduces swelling capacity by 23% and plasticity index by 5%. Bentonite/steel interaction studies show corrosion precipitates diffusing into compacted bentonite up to 3mm from the interface over a 4 month exposure (increasing with temperature), with reduction in swelling capacity in the affected zone, probably due to the development of poorly crystalline iron oxides. These results indicate that groundwater conditions, temperature and corrosion

  7. Thermal modeling of pluton emplacement and associated contact metamorphism:Parashi stock emplacement in the Serranía de Jarara (Alta Guajira, Colombia

    Directory of Open Access Journals (Sweden)

    Zuluaga C. Carlos A.

    2010-12-01

    Full Text Available

    In the northernmost portion of the Serrania de Jarara (Alta Guajira, Colombia, low - medium grade metamorphic rocks from the Etpana Metamorphic Suite were thermally affected by emplacement of a small calc-alkaline intrusion (Parashi Stock. Detailed petrographic analysis in collected rock samples across the NE and NW plutonic contacts show occurrences of textural and mineralogical changes in the country rock fabric that evidence contact metamorphism overprinting regional metamorphism of the Etpana Suite. These changes include growth of andalusite (chiastolite, calcic clinopyroxeneand amphibole porphyroblast crosscutting Sn+1 metamorphicfoliation. Hornblende-plagioclase barometry (ca. 3.1 kbar and cooling models for the stock show maximum time temperature evolution in the country rock at the interpreted depth of intrusion (ca. 11 km and help to evaluate the behavior of the country rock with the changing local geotherm.

  8. Emplacement Temperatures of Pyroclastic and Volcaniclastic Deposits in Kimberlite Pipes in Southern Africa: New constraints From Palaeomagnetic Measurements

    Science.gov (United States)

    Fontana, G. P.; Macniocaill, C.; Brown, R. J.; Sparks, S. R.; Field, M.; Gernon, T. M.

    2009-05-01

    Palaeomagnetic techniques for estimating the emplacement temperatures of volcanic deposits have been applied for the first time to pyroclastic and volcaniclastic deposits in kimberlite pipes in southern Africa. Lithic clasts were sampled from a variety of lithofacies, from three pipes for which the internal geology is well constrained (A/K1 pipe, Orapa Mine, Botswana and the K1 and K2 pipes, Venetia Mine, South Africa). The sampled deposits included massive and layered vent-filling breccias with varying abundances of lithic inclusions and layered crater-filling pyroclastic deposits, talus breccias and volcaniclastic breccias. Lithic clasts sampled from layered and massive vent-filling pyroclastic deposits in A/K1 were emplaced at >590° C. Results from K1 and K2 provide a maximum emplacement temperature limit for vent-filling breccias of 420-460° C; and constrain equilibrium deposit temperatures at 300-340° C. Crater-filling volcaniclastic kimberlite breccias and talus deposits from A/K1 were emplaced at ambient temperatures, consistent with infilling of the pipe by post-eruption epiclastic processes. Identified within the epiclastic crater- fill succession is a laterally extensive 15-20 metre thick kimberlite pyroclastic flow deposit emplaced at temperatures of 220-440° C. It overlies the post-eruption epiclastic units and is considered an extraneous pyroclastic kimberlite deposit erupted from another kimberlite vent. The emplacement temperature results are comparable to the estimated emplacement temperatures of other kimberlite deposits and pyroclastic deposits from other volcanic systems, and fall within the proposed stability field for common interstitial matrix mineral assemblages within vent-filling volcaniclastic kimberlites. This is in the range where welding and agglutination of juvenile pyroclasts occurs in other types of pyroclastic deposits. Such high emplacement temperatures for vent-filling pyroclastic deposits are consistent with volatile

  9. Experiment and performance study on the performance of brushless doubly-fed machine with barrier rotor%磁障转子无刷双馈电机运行特性及实验研究

    Institute of Scientific and Technical Information of China (English)

    张岳; 王凤翔

    2014-01-01

    In order to investigate the magnetic coupled performance of brushless doubly-fed machines(BD-FM), a magnetic barrier rotor structure of BDFM with simple structure and good performance is pro-posed. A 6/2 poles numbers and rated power 5 kW brushless-fed reluctance machine with magnetic barri-er rotor was designed by ansoft software. The characteristic of operation for BDFM with magnetic barrier rotor was analyzed. On these bases, the open-loop experiment of variable speed constant frequency (VSCF) for BDFG with magnetic barrier rotor was realized. The theoretical analysis and experimental study show that the performance of BDFM with reluctance rotor can be effectively improved by adding magnetic barrier properly in the rotor core, and the machine can keep the same advantages of simple structure and low cost as that of the normal reluctance rotor.%针对普通凸极磁阻转子无刷双馈电机的转子耦合能力差、效率低的问题,提出一种结构简单、性能良好的磁障转子结构,设计了额定功率为5kW、6/2极的转子带磁障的无刷双馈磁阻电机,运用有限元法分析了转子带磁障无刷双馈磁阻电机的电动和发电运行特性,在此基础上,对转子带磁障的无刷双馈电机进行了变速恒频发电的开环实验。理论分析和实验研究结果表明:适当在转子铁心中加入磁障,可以有效改善转子带磁障的无刷双馈磁阻电机的性能,同时又保留普通凸极磁阻转子结构简单和成本低廉的优点,为今后设计大功率磁障转子无刷双馈磁阻电机提供有价值的参考依据。

  10. Message maps for Safety Barrier Awareness

    DEFF Research Database (Denmark)

    All people are exposed to risks in every-day life, but they seldom experience accidents. Therefore people often believe that these accidents will never happen, and they will see the risks no more. By increasing the ability to notice risks, to see safety barriers, and to assess the safety barriers...

  11. Study of fission barriers in neutron-rich nuclei using the (p,2p) reaction. Status of SAMURAI-experiment NP1306 SAMURAI14

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, Sebastian [TU Munich (Germany); Collaboration: NP1306-SAMURAI14-Collaboration

    2015-07-01

    Violent stellar processes are currently assumed to be a major origin of the elements beyond iron and their abundances. The conditions during stellar explosions lead to the so called r-process in which the rapid capture of neutrons and subsequent β decays form heavier elements. This extension of the nuclei stops at the point when the repulsive Coulomb energy induces fission. Its recycling is one key aspect to describe the macroscopic structure of the r-process and the well known elemental abundance pattern. The RIBF at RIKEN is able to provide such neutron rich heavy element beams and a first test with the primary beam {sup 238}U was performed to understand the response of the SAMURAI spectrometer and detectors for heavy beams. The final goal is the definition of the fission barrier height with a resolution of 1 MeV (in σ) using the missing mass method using (p,2p) reactions in inverse kinematics.

  12. Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling

    Science.gov (United States)

    Jin, Chao; Glawdel, Tomasz; Ren, Carolyn L.; Emelko, Monica B.

    2015-12-01

    Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or “sag effect” was identified. This effect was more significant for nanoparticles (surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition.

  13. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-05-06

    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

  14. Emplacement temperatures of the November 22, 1994 nuee ardente deposits, Merapi Volcano, Java

    Science.gov (United States)

    Voight, B.; Davis, M.J.

    2000-01-01

    A study of emplacement temperatures was carried out for the largest of the 22 November 1994 nuée ardente deposits at Merapi Volcano, based mainly on the response of plastic and woody materials subjected to the hot pyroclastic current and the deposits, and to some extent on eyewitness observations. The study emphasizes the Turgo–Kaliurang area in the distal part of the area affected by the nuée ardente, where nearly 100 casualties occurred. The term nuée ardente as used here includes channeled block-and-ash flows, and associated ash-clouds of surge and fallout origins. The emplacement temperature of the 8 m thick channeled block-and-ash deposit was relatively high, ∼550°C, based mainly on eyewitness reports of visual thermal radiance. Emplacement temperatures for ash-cloud deposits a few cm thick were deduced from polymer objects collected at Turgo and Kaliurang. Most polymers do not display a sharp melting range, but polyethylene terephthalate used in water bottles melts between 245 and 265°C, and parts of the bottles that had been deformed during fabrication molding turn a milky color at 200°C. The experimental evidence suggests that deposits in the Turgo area briefly achieved a maximum temperature near 300°C, whereas those near Kaliurang were <200°C. Maximum ash deposit temperatures occurred in fallout with a local source in the channeled block-and-ash flow of the Boyong river valley; the surge deposit was cooler (∼180°C) due to entrainment of cool air and soils, and tree singe-zone temperatures were around 100°C.

  15. Sensor Emplacement Techniques and Seismic Noise Analysis for USArray Transportable Array Seismic Stations

    Science.gov (United States)

    Frassetto, A.; Busby, R. W.; Hafner, K.; Woodward, R.; Sauter, A.

    2013-12-01

    In preparation for the upcoming deployment of EarthScope's USArray Transportable Array (TA) in Alaska, the National Science Foundation (NSF) has supported exploratory work on seismic station design, sensor emplacement, and communication concepts appropriate for this challenging high-latitude environment. IRIS has installed several experimental stations to evaluate different sensor emplacement schemes both in Alaska and in the lower-48 of the U.S. The goal of these tests is to maintain or enhance a station's noise performance while minimizing its footprint and the weight of the equipment, materials, and overall expense required for its construction. Motivating this approach are recent developments in posthole broadband seismometer design and the unique conditions for operating in Alaska, where there are few roads, cellular communications are scarce, most areas are only accessible by small plane or helicopter, and permafrost underlies much of the state. We will review the methods used for directly emplacing broadband seismometers in comparison to the current methods used for the lower-48 TA. These new methods primarily focus on using a portable drill to make a bored hole three to five meters, beneath the active layer of the permafrost, or by coring 1-2 meters deep into surface bedrock. Both methods are logistically effective in preliminary trials. Subsequent station performance has been assessed quantitatively using probability density functions summed from power spectral density estimates. These are calculated for the continuous time series of seismic data recorded for each channel of the seismometer. There are five test stations currently operating in Alaska. One was deployed in August 2011 and the remaining four in October 2012. Our results show that the performance of seismometers in Alaska with auger-hole or core-hole installations can sometimes exceed that of the quietest TA stations in the lower-48, particularly horizontal components at long periods. A

  16. Deformation of poorly consolidated sediment during shallow emplacement of a basalt sill, Coso Range, California

    Science.gov (United States)

    Duffield, W.A.; Bacon, C.R.; Delaney, P.T.

    1986-01-01

    A 150-m-long, wedge-shaped unit of folded and faulted marly siltstone crops out between undeformed sedimentary rocks on the north flank of the Coso Range, California. The several-meter-thick blunt end of this wedge abuts the north margin of a basaltic sill of comparable thickness. Chaotically deformed siltstone crops out locally at the margin of this sill, and at one locality breccia pipes about one meter in diameter crosscut the sill. The sill extends about 1 km south up the paleoslope, where it merges through continuous outcrop with a lava flow that in turn extends 1.4 km to a vent area marked by more than 100 m of agglutinate and scoria. Apparently, lava extruded at this vent flowed onto unconsolidated sediments, burrowed into them, and fed a sill at about 40 m depth within the sedimentary sequence. The sill initially propagated by wedging between sedimentary beds, but eventually began to push some beds ahead of itself, forming a remarkable train of folds in the process. The sediments apparently were wet at the time of sill emplacement, because hydrothermal alteration is common near the contact between the two rock types and because the breccia pipes that crosscut the sill apparently resulted from phreatic explosions of pore water heated at the base of the cooling sill. Comparison of deformation of the host material at the Coso locality with that reportedly caused by emplacement of sills elsewhere indicates that the character of deformation differs greatly among the various localities. The specific response of host material depends upon such parameters as initial properties of magma and host material, rate of sill growth and attendant rate of strain of host material, and depth of sill emplacement. Some properties may change considerably during an intrusive-deformational episode, thus complicating accurate reconstruction of such an event. ?? 1986 Springer-Verlag.

  17. Evaluation of emplacement sensors for detecting radiation and volatile organic compounds and for long-term monitoring access tubes for the BWCS

    Energy Technology Data Exchange (ETDEWEB)

    Lord, D.L.; Averill, R.H.

    1997-10-01

    This document evaluates sensors for detecting contaminants in the excavated waste generated by the Buried Waste Containment System (BWCS). The Barrier Placement Machine (BPM) removes spoils from under a landfill or plume and places it on a conveyor belt on the left and right sides of the BPM. The spoils will travel down the conveyor belts past assay monitors and be deposited on top of the site being worked. The belts are 5 ft wide and transport approximately 15 ft3 /minute of spoils. This corresponds to a 10 ft per hour BPM advance rate. With a 2 in. spoils height the belt speed would be 3.6 in. per second. The spoils being removed are expected to be {open_quotes}clean{close_quotes} (no radiation or volatile organics above background levels). To ensure that the equipment is not digging through a contaminated area, assay equipment will monitor the spoils for mg radiation and volatile organic compounds (VOCs). The radiation monitors will check for gross radiation indication. Upon detection of radiation levels above a predetermined setpoint, further evaluation will be performed to determine the isotopes present and their quantity. This will require hand held monitors and a remote monitoring station. Simultaneously, VOC monitors will monitor for predetermined volatile/semi-volatile organic compounds. A Fourier-Transform Infrared Spectrometer (FTIR) monitor is recommended for this operation. Specific site requirements and regulations will determine setpoints and operation scenarios. If VOCs are detected, the data will be collected and recorded. A flat panel display will be mounted in the BPM operator`s cab showing the radio nuclide and VOC monitoring data. As the BPM advances, a 3-in. diameter PVC tube will be placed on the bottom of the barrier slot in front of the 12 to 16-in. containment barrier being emplaced.

  18. Communicating across barriers at home and abroad

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, J.W.

    1985-01-01

    This paper intends to catalyze the exchange of experience among technical communicators in meeting the challenge of communicating across a multitude of barriers: linguistic, disciplinary, cultural, political, intellectual, and emotional.

  19. Engineered Barrier System: Physical and Chemical Environment Model

    Energy Technology Data Exchange (ETDEWEB)

    D. M. Jolley; R. Jarek; P. Mariner

    2004-02-09

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  20. ENGINEERED BARRIER SYSTEM FEATURES, EVENTS AND PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Jaros, W.

    2005-08-30

    The purpose of this report is to evaluate and document the inclusion or exclusion of engineered barrier system (EBS) features, events, and processes (FEPs) with respect to models and analyses used to support the total system performance assessment for the license application (TSPA-LA). A screening decision, either Included or Excluded, is given for each FEP along with the technical basis for exclusion screening decisions. This information is required by the U.S. Nuclear Regulatory Commission (NRC) at 10 CFR 63.114 (d, e, and f) [DIRS 173273]. The FEPs addressed in this report deal with those features, events, and processes relevant to the EBS focusing mainly on those components and conditions exterior to the waste package and within the rock mass surrounding emplacement drifts. The components of the EBS are the drip shield, waste package, waste form, cladding, emplacement pallet, emplacement drift excavated opening (also referred to as drift opening in this report), and invert. FEPs specific to the waste package, cladding, and drip shield are addressed in separate FEP reports: for example, ''Screening of Features, Events, and Processes in Drip Shield and Waste Package Degradation'' (BSC 2005 [DIRS 174995]), ''Clad Degradation--FEPs Screening Arguments (BSC 2004 [DIRS 170019]), and Waste-Form Features, Events, and Processes'' (BSC 2004 [DIRS 170020]). For included FEPs, this report summarizes the implementation of the FEP in the TSPA-LA (i.e., how the FEP is included). For excluded FEPs, this analysis provides the technical basis for exclusion from TSPA-LA (i.e., why the FEP is excluded). This report also documents changes to the EBS FEPs list that have occurred since the previous versions of this report. These changes have resulted due to a reevaluation of the FEPs for TSPA-LA as identified in Section 1.2 of this report and described in more detail in Section 6.1.1. This revision addresses updates in Yucca Mountain Project

  1. Crystallization and emplacement of the Lac St-Jean anorthosite massif (Quebec, Canada)

    Science.gov (United States)

    Woussen, G.; Dimroth, E.; Corriveau, L.; Archer, P.

    1981-05-01

    The Lac St-Jean anorthosite massif underlies an area of over 20,000 km2 and has been emplaced into migmatitic gneisses of the central granulite terrain of the Grenville Province of the Canadian shield. Field data and petrography in an area straddling the anorthosite-gneiss contact, close to Chicoutimi (Quebec) permits an outline of its tecto-magmatic evolution. Depositional magmatic textures in the massif reveals that it crystallized from a magma in a relatively calm tectonic environment. The absence of fusion in pelitic gneisses at the contact proves that the crystallization did not take place at the level presently exposed. The parallelism of subvertical foliation in the enveloping gneisses and the anorthosite indicates that both were deformed together. It is suggested that the deformation results from a diapiric ascent of the anorthosite massif after its consolidation at depth. The depth of consolidation of the anorthosite is estimated at ˜ 25 30 km from subsolidus reaction between plagioclase and olivine. The diapiric ascent is further substantiated by the fact that three sets of mafic dykes of different ages, intrusive into the anorthosite, have a mineralogy which indicates successively decreasing P, T conditions of emplacement from granulite fades to amphibolite facies. An evolution of the basement gneisses and the anorthosite is proposed as a working hypothesis; it relies on the fact that metabasite dyke swarms in the basement gneisses represent a period of major crustal extension and could be used as a stratigraphic subdivision of the Grenville Province.

  2. Mine stability evaluation of panel 1 during waste emplacement operations at WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Maleki, H. [Maleki Technologies Inc., Spokane, WA (United States)

    1998-07-01

    The specific objectives of the work were defined by the Environmental Evaluation Group (EEG) as follows: (1) assess the stability of panel 1 during the proposed operation of waste emplacement; (2) estimate the amount of time before room closure would be expected to transfer rock loads to the waste packages. The work consisted of (1) an analysis of geotechnical data and a review of the Department of Energy`s (DOE) plans for waste emplacement in panel 1, (2) an evaluation of ground conditions based on data analysis and observations of changes in ground conditions since the first evaluation in 1993 (USBM 1993), and (3) preparation of a report and presentation of the results to EEG staff. Excluded from this study are radiological safety issues and policies. The study is based on data provided by DOE and Westinghouse Electric Corporation (operator of the site) and conversations with DOE and Westinghouse personnel. MTI cannot independently verify the accuracy of the data within the scope of this study and recommends independent evaluations of data gathering, quality assurance procedures, and structural designs. The operator has the ultimate responsibility for structural designs and has expressed a strong commitment to ensuring worker safety.

  3. Emplacement of a Thick Mafic Extrusive Body: A CSD Solution to a Map-Generated Question

    Science.gov (United States)

    Pollock, M.; Sloan, J. A.; Siler, D. L.; Karson, J.

    2011-12-01

    A petrological study of crystallization in thick extrusive bodies is motivated by the geologic mapping of glacially excavated volcanic crust exposed along the Vatnsdalsfjall mountain range in northwest Iceland. Vatnsdalsfjall reveals a regional flexure zone, in which ~7 Ma lava flows dip 5-10° westward toward the extinct Skagi-Hunafloi rift axis. The regional flexure is disrupted by a local bowl-shaped depression, where lava flows steepen to ~50° as they dip below a ~250 m thick, ~3 km long igneous unit known as the Hjallin lens (HL). Its lenticular shape and well-developed columnar jointing most likely led Annels (1968) to initially map the HL as a shallow-level intrusion. However, more recent field investigations by McClanahan and Wobus (2004) reveal that the HL is an extrusive body, as evidenced by a distinct basal contact that consists of a flow-banded rhyolitic ash flow tuff underlain by a sedimentary layer containing organic material. Based on preliminary petrologic and geochemical analyses, McClanahan and Wobus (2004) describe the HL as a fine-grained, aphyric basalt that is nearly uniform in mineralogy, texture, and composition. Further field work by Siler (2011) shows that the HL overlies basaltic lavas that thicken toward the center of the bowl-shaped depression, indicating that the lava flows were emplaced during subsidence. The mapped relationship of the HL to the underlying lava flows suggests that the lens is a syn- (or post-) subsidence extrusion emplaced into an existing paleotopographic low. When considered with the field relationships, the homogeneous and fine-grained character of the lens naturally presents a petrological question: Was the anomalously thick extrusive body emplaced in a single eruptive event or is the HL the product of multiple flows that erupted in rapid succession? To understand the formation the HL, we measured the crystal size distribution (CSD) of plagioclase in backscattered electron (BSE) images of 20 samples from three

  4. In situ thermal characterization of cooling/crystallizing lavas during rheology measurements and implications for lava flow emplacement

    Science.gov (United States)

    Kolzenburg, S.; Giordano, D.; Cimarelli, C.; Dingwell, D. B.

    2016-12-01

    Transport properties of natural silicate melts at super-liquidus temperatures are reasonably well understood. However, migration and transport of silicate melts in the Earth's crust and at its surface generally occur at sub-liquidus temperatures and in settings where the melts undergo crystallization under various cooling and/or decompression conditions. In such dynamic situations the occurrence of processes such as the release of latent heat during phase changes, viscous heating, thermal advection and -inertia, and changing heat capacity, all represent potential influences on the state, and thereby on the physico-chemical behavior of the system. To date, rheological data at sub-liquidus temperatures are scarce and cooling-rate dependent, disequilibrium rheological data are virtually absent. In fact, no in situ thermal characterization of liquid or multiphase mixtures during rheological experiments, under either static or dynamic thermal conditions has been presented to date. Here we describe a new experimental setup for in situ thermal characterization of cooling/crystallizing lavas during viscosity measurement at temperatures up to 1600 °C. We use this device to recover in situ, real-time, observations of the combined rheological and thermal evolution of natural, re-melted lava samples during the transient disequilibrium conditions characteristic of lava flows and shallow crustal magma migration and storage systems in nature. We present the calibration procedure and the method employed to recover the thermal evolution of an experimental sample during flow in varying shear regimes, assess the experimental uncertainty and show the ability of the apparatus to measure the release of latent heat of crystallization during transient rheological experiments. We further report the results from a first experimental study on the rheological and thermal evolution of a basaltic lava undergoing continuous cooling at a series of different cooling rates and discuss the

  5. The mode of emplacement of Neogene flood basalts in eastern Iceland: Facies architecture and structure of simple aphyric basalt groups

    Science.gov (United States)

    Óskarsson, Birgir V.; Riishuus, Morten S.

    2014-12-01

    Simple flows (tabular) in the Neogene flood basalt sections of Iceland are described and their mode of emplacement assessed. The flows belong to three aphyric basalt groups: the Kumlafell group, the Hólmatindur group and the Hjálmadalur group. The groups can be traced over 50 km and originate in the Breiðdalur-Thingmuli volcanic zone. The groups have flow fields that display mixed volcanic facies architecture and can be classified after dominating type morphology. The Kumlafell and the Hólmatindur groups have predominantly simple flows of pāhoehoe and rubbly pāhoehoe morphologies with minor compound or lobate pāhoehoe flows. The Hjálmadalur group has simple flows of rubbly pāhoehoe, but also includes minor compound or lobate flows of rubble and 'a'ā. Simple flows are most common in the distal and medial areas from the vents, while more lobate flows in proximal areas. The simple flows are formed by extensive sheet lobes that are several kilometers long with plane-parallel contacts, some reaching thicknesses of ~ 40 m (aspect ratios inflation structures. Their internal structure consists generally of a simple upper vesicular crust, a dense core and a thin basal vesicular zone. The brecciated flow-top is formed by clinker and crustal rubble, the clinker often welded or agglutinated. The simple flows erupted from seemingly short-lived fissures and have the characteristics of cooling-limited flows. We estimate the effusion rates to be ~ 105 m3/s for the simple flows of the Kumlafell and Hólmatindur groups and ~ 104 m3/s for the Hjálmadalur group. The longest flows advanced 15-20 km from the fissures, with lava streams of fast propagating flows inducing tearing and brecciation of the chilled crust. Compound or lobate areas appear to reflect areas of low effusion rates or the interaction of the lava with topographic barriers or wetlands, resulting in chaotic flowage. Slowing lobes with brecciated flow-tops developed into 'a'ā flows. The groups interdigitated

  6. Extremal surface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Netta; Wall, Aron C. [Department of Physics, University of California,Santa Barbara, CA 93106 (United States)

    2014-03-13

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy.

  7. Safety-barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2007-01-01

    are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk......Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian networks...... analysis with operational safety management....

  8. A reappraisal of ignimbrite emplacement: progressive aggradation and changes from particulate to non-particulate flow during emplacement of high-grade ignimbrite

    Science.gov (United States)

    Branney, Michael J.; Kokelaar, Peter

    1992-08-01

    continuously during the passage of a quasi-steady flow supplied by a sustained explosive eruption. Vertical facies successions developed in the deposit (high-grade ignimbrite) reflect temporal changes in flow steadiness and in material supplied at source. The P-NP transition is also influenced by factors that affect flow behaviour, such as topography. It may occur at any location laterally between a proximal site of deflation (e.g. a fountain-fed lava) and a flow's distal limit, but it most commonly occurs throughout a considerable length of the flow path. Up-sequence variations in welding-deformation fabric (between oblate uniaxial to triaxial and prolate) reflect evolving characteristics of the depositional boundary layer (e.g. fluctuations from direct suspension-sedimentation to deposition via traction carpets or traction plugs), as well as possible modifications resulting from subsequent, post-depositional hot loading and slumping. Similar processes can also account for lateral lithofacies gradations in conduits and vents filled with welded tuff. Our consideration of high-grade ignimbrites has implications for ignimbrite emplacement in general, and draws attention to the limitations of the widely accepted models of emplacement involving mainly high-concentration non-turbulent transport and en masse ‘freezing’ of high-yield-strength plug flows.

  9. Interprofessional experiences of recent healthcare graduates: A social psychology perspective on the barriers to effective communication, teamwork, and patient-centred care.

    Science.gov (United States)

    Thomson, Krist; Outram, Sue; Gilligan, Conor; Levett-Jones, Tracy

    2015-01-01

    Achieving safe, quality health care is highly dependent on effective communication between all members of the healthcare team. This study explored the attitudes and experiences of recent healthcare graduates regarding interprofessional teamwork and communication within a clinical setting. A total of 68 pharmacy, nursing, and medicine graduates participated in 12 semi-structured focus group discussions in clinical workplaces across three Australian states. Discussion focussed on graduates' experiences of interprofessional education and its impact on their capacity for interprofessional teamwork and communication. The Social Identity and Realistic Conflict theories were used as a framework for qualitative data analysis. A consistent pattern of profession-focussed, rather than patient- or team-focussed goals was revealed along with reports of negative stereotyping, hierarchical communication, and competition for time with the patient. Graduates acknowledged the importance of communication, teamwork, and patient-centred care and felt a better understanding of the roles of other health professionals would assist them to work together for patients' wellbeing. Identifying workplace identities and differential goals has uncovered possible motivations underlying health professionals' behaviour. These insights may help improve interprofessional collaboration by focusing attention on common team goals, increasing feelings of worth and being valued among different professionals, and decreasing the need for competition.

  10. Barriers to physical activity among working mothers.

    Science.gov (United States)

    Dombrowski, Jill J

    2011-04-01

    Working mothers experience several barriers to physical activity. If these barriers can be identified by occupational health nurses and they can partner with working mothers to reduce these perceived barriers, the health of these workers can be improved and chronic disease risk prevented. The purpose of this study was to measure the effect of self-regulatory efficacy on physical activity among working mothers and to describe specific barriers to physical activity. The Barriers Specific Self-Efficacy Scale (BARSE) and the Kaiser Physical Activity Survey (KPAS) were used to measure the variables. Self-regulatory efficacy was found to be a strong predictor of physical activity in a diverse sample of working mothers who did not meet current recommendations for physical activity. Occupational health nurses can use these findings to design programs for groups and for counseling individuals.

  11. Verification of the integrity of barriers using gas diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Ward, D.B. [SPECTRA Research Inst., Albuquerque, NM (United States); Williams, C.V. [Sandia National Labs., Albuquerque, NM (United States). Environmental Restoration Technologies Dept.

    1997-06-01

    In-situ barrier materials and designs are being developed for containment of high risk contamination as an alternative to immediate removal or remediation. The intent of these designs is to prevent the movement of contaminants in either the liquid or vapor phase by long-term containment, essentially buying time until the contaminant depletes naturally or a remediation can be implemented. The integrity of the resultant soil-binder mixture is typically assessed by a number of destructive laboratory tests (leaching, compressive strength, mechanical stability with respect to wetting and freeze-thaw cycles) which as a group are used to infer the likelihood of favorable long-term performance of the barrier. The need exists for a minimally intrusive yet quantifiable methods for assessment of a barrier`s integrity after emplacement, and monitoring of the barrier`s performance over its lifetime. Here, the authors evaluate non-destructive measurements of inert-gas diffusion (specifically, SF{sub 6}) as an indicator of waste-form integrity. The goals of this project are to show that diffusivity can be measured in core samples of soil jet-grouted with Portland cement, validate the experimental method through measurements on samples, and to calculate aqueous diffusivities from a series of diffusion measurements. This study shows that it is practical to measure SF{sub 6} diffusion rates in the laboratory on samples of grout (Portland cement and soil) typical of what might be used in a barrier. Diffusion of SF{sub 6} through grout (Portland cement and soil) is at least an order of magnitude slower than through air. The use of this tracer should be sensitive to the presence of fractures, voids, or other discontinuities in the grout/soil structure. Field-scale measurements should be practical on time-scales of a few days.

  12. Neo-tectonic fracturing after emplacement of quaternary granitic pluton in the Kakkonda geothermal field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Doi, N.; Kato, O. [JMC Goethermal Eng. Co., Ltd., Iwate-ken (Japan); Kanisawa, S.; Ishikawa, K. [Tohoku Univ., Sendai (Japan)

    1995-12-31

    The fracture which occurs in the Kakkonda geothermal system was formed by neo-tectonic stress after the emplacement of the neo-granite (Quaternary Kakkonda Granite) at middle Pleistocene to recent. The characteristic contrast in permeability at ca.1.5 km is strongly controlled by the contact metamorphic zone, especially cordierite and higher grade metamorphic zones, in which the high temperature (320{degrees}C<) and low permeable deep reservoir was created. The five geothermal wells 2.5-3.0 km deep have clarified that a microearthquake zone below -1.0 km shows high permeability especially at the margin of the Kakkonda Granite, and low permeability outside of a microearthquake zone. The Kakkonda Granite is a composite pluton which has very few fractures inside of it. Thus, neo-tectonic fracturing has developed in the non-metamorphosed Tertiary formations and the margin of the Kakkonda Granite.

  13. STARR: shortwave-targeted agile Raman robot for the detection and identification of emplaced explosives

    Science.gov (United States)

    Gomer, Nathaniel R.; Gardner, Charles W.

    2014-05-01

    In order to combat the threat of emplaced explosives (land mines, etc.), ChemImage Sensor Systems (CISS) has developed a multi-sensor, robot mounted sensor capable of identification and confirmation of potential threats. The system, known as STARR (Shortwave-infrared Targeted Agile Raman Robot), utilizes shortwave infrared spectroscopy for the identification of potential threats, combined with a visible short-range standoff Raman hyperspectral imaging (HSI) system for material confirmation. The entire system is mounted onto a Talon UGV (Unmanned Ground Vehicle), giving the sensor an increased area search rate and reducing the risk of injury to the operator. The Raman HSI system utilizes a fiber array spectral translator (FAST) for the acquisition of high quality Raman chemical images, allowing for increased sensitivity and improved specificity. An overview of the design and operation of the system will be presented, along with initial detection results of the fusion sensor.

  14. Near-roof structure and crack-seal emplacement, Colosseum pluton, Sierra Nevada, California

    Science.gov (United States)

    Bartley, J. M.; Glazner, A. F.; Coleman, D. S.

    2011-12-01

    Field evidence from diverse localities indicates that dike-like granitic plutons are emplaced by magmatic crack-seal, yielding plutons that are essentially huge composite dikes. Plutons that are equant in map view may also form by crack-seal from increments that are subhorizontal and vertically stacked, but field evidence to assess this hypothesis is scarce. Here we present evidence that the Late Cretaceous, granitic Colosseum pluton of Moore (1963), which crops out along the Sierra Nevada crest southwest of Big Pine, California, may have been emplaced as horizontal sheets by crack-seal. The equant outcrop pattern of the elliptical, 2x3 km Colosseum pluton as mapped by Moore (1963) mainly reflects Pleistocene glacial erosion that cut ~600 m down through the pluton's gently sloping roof contact. Moore mapped a steep eastern contact with the Spook pluton, but our field observations suggest that the Spook and Colosseum plutons may be the same. This would imply that the pluton is much larger and that the map pattern is not elliptical. Additionally, the exposed intrusive contact everywhere dips gently, but the eastern intrusive contact has been cut off by the Sierran frontal fault. If so, up to 2.5 km of largely unexplored vertical relief in the pluton is exposed on the eastern escarpment of the Sierra Nevada. Geologic and bulk magnetic susceptibility mapping of near-roof rocks revealed the following. (1) Although the intrusive contact sharply truncates wall-rock foliation, xenoliths are absent, even at contacts, indicating that stoping was an insignificant process. (2) The pluton contains a subhorizontal sheet of leucogranite that is broadly concordant with the roof but bounded both above and below by more typical biotite granodiorite. This sheet may represent one or more intrusive increments. (3) Along the western contact, thin tabular apophyses of the pluton intrude its subvertically layered and foliated roof. Although some of these dip steeply and are concordant

  15. The Sonju Lake layered intrusion, northeast Minnesota: Internal structure and emplacement history inferred from magnetic fabrics

    Science.gov (United States)

    Maes, S.M.; Tikoff, B.; Ferre, E.C.; Brown, P.E.; Miller, J.D.

    2007-01-01

    The Sonju Lake intrusion (SLI), in northeastern Minnesota, is a layered mafic complex of Keweenawan age (1096.1 ?? 0.8 Ma) related to the Midcontinent rift. The cumulate paragenesis of the intrusion is recognized as broadly similar to the Skaergaard intrusion, a classic example of closed-system differentiation of a tholeiitic mafic magma. The SLI represents nearly closed-system differentiation through bottom-up fractional crystallization. Geochemical studies have identified the presence of a stratabound, 50-100 m thick zone anomalously enriched in Au + PGE. Similar to the PGE reefs of the Skaergaard intrusion, this PGE-enriched zone is hosted within oxide gabbro cumulates, about two-third of the way up from the base of the intrusion. We present a petrofabric study using the anisotropy of magnetic susceptibility (AMS) to investigate the emplacement and flow patterns within the Sonju Lake intrusion. Petrographic and electron microprobe studies, combined with AMS and hysteresis measurements indicate the primary source of the magnetic signal is pseudo-single domain (PSD) magnetite or titanomagnetite. Low field AMS was measured at 32 sites within the Sonju Lake intrusion, which provided information about primary igneous fabrics. The magnetic fabrics in the layered series of the Sonju Lake intrusion are consistent with sub-horizontal to inclined emplacement of the intrusion and show evidence that the cumulate layers were deposited in a dynamic environment. Well-aligned magnetic lineations, consistently plunging shallowly toward the southwest, indicate the source of the magma is a vertical sill-like feeder, presumably located beneath the Finland granite. The Finland granite acted as a density trap for the Sonju Lake magmas, forcing lateral flow of magma to the northeast. The strongly oblate magnetic shape fabrics indicate the shallowly dipping planar fabrics were enhanced by compaction of the crystal mush. ?? 2007 Elsevier B.V. All rights reserved.

  16. Incorporation of seawater into mid-ocean ridge lava flows during emplacement

    Science.gov (United States)

    Soule, S. A.; Fornari, D. J.; Perfit, M.; Cann, J. R.; Montési, L.; Ridley, W. I.

    2005-12-01

    Mid-ocean ridge (MOR) lava flows erupted at ~2000-3500 m below sea level contain large, cm- to m-sized cavities close to the upper surfaces of the flows. Within these cavities, lava drips (similar to lava stalactites found in terrestrial lava tubes) hang from the base of the upper crust. In order for these features to form, the cavities must exist as vapor-filled open space under hydrostatic pressures up to 35 MPa, and must maintain near-magmatic temperatures to attain the observed morphology of the drips. We have examined numerous lobate and sheet lava crusts from the fast-spreading East Pacific Rise in order to constrain the nature of the vapor that filled the cavities beneath these crusts, the extent of the interaction between the vapor and the liquid lava, and the impact of the vapor phase on flow emplacement. On the inner surfaces of large vesicles and cavities within the flow are mineral phases that appear to have grown at the interface between the liquid lava and vapor. These mineral phases have compositions distinct from those found in the flow interior (e.g., pure albite and forsterite), and show mineral growth habits indicative of undercooling of the lava. Preliminary thermodynamic modeling of the gas-liquid-solid interaction suggests that vapor derived from heated seawater is capable of producing the observed mineral compositions. In addition, we have found that quenched glass adjacent to analyzed vesicles can be enriched in Cl by an order of magnitude over ambient glass within the same sample suggesting that local mass exchange between the seawater and the lava has occurred. Here we present results of these analyses and accompanying thermodynamic modeling that lead us to conclude that the vapor filling the cavities is derived directly from seawater. In addition, we present numerical models investigating mechanisms for seawater incorporation and its impact on flow emplacement.

  17. Coeval emplacement and orogen-parallel transport of gold in oblique convergent orogens

    Science.gov (United States)

    Upton, Phaedra; Craw, Dave

    2016-12-01

    Varying amounts of gold mineralisation is occurring in all young and active collisional mountain belts. Concurrently, these syn-orogenic hydrothermal deposits are being eroded and transported to form placer deposits. Local extension occurs in convergent orogens, especially oblique orogens, and facilitates emplacement of syn-orogenic gold-bearing deposits with or without associated magmatism. Numerical modelling has shown that extension results from directional variations in movement rates along the rock transport trajectory during convergence, and is most pronounced for highly oblique convergence with strong crustal rheology. On-going uplift during orogenesis exposes gold deposits to erosion, transport, and localised placer concentration. Drainage patterns in variably oblique convergent orogenic belts typically have an orogen-parallel or sub-parallel component; the details of which varies with convergence obliquity and the vagaries of underlying geological controls. This leads to lateral transport of eroded syn-orogenic gold on a range of scales, up to > 100 km. The presence of inherited crustal blocks with contrasting rheology in oblique orogenic collision zones can cause perturbations in drainage patterns, but numerical modelling suggests that orogen-parallel drainage is still a persistent and robust feature. The presence of an inherited block of weak crust enhances the orogen-parallel drainage by imposition of localised subsidence zones elongated along a plate boundary. Evolution and reorientation of orogen-parallel drainage can sever links between gold placer deposits and their syn-orogenic sources. Many of these modelled features of syn-orogenic gold emplacement and varying amounts of orogen-parallel detrital gold transport can be recognised in the Miocene to Recent New Zealand oblique convergent orogen. These processes contribute little gold to major placer goldfields, which require more long-term recycling and placer gold concentration. Most eroded syn

  18. Subsurface ices at the Mars Phoenix Landing Site: Assessing emplacement mechanisms

    Science.gov (United States)

    Cull, S.; Arvidson, R. E.; Mellon, M. T.; Skemer, P. A.; Shaw, A.; Morris, R. V.

    2010-12-01

    Several mechanisms have been proposed to explain the emplacement of subsurface ices on Mars: vapor diffusion from the atmosphere, freezing of bodies of surface water (e.g., lakes or oceans), buried glaciers, or accumulation and burial of packed snow. These formation mechanisms predict different physical properties for the subsurface ices: vapor diffusion should produce pore ice, whereas other mechanisms should produce massive, relatively pure ice. NASA's Phoenix Lander uncovered two types of ice at its 2008 landing site on the northern plains of Mars: a light-toned ice (Dodo-Goldilocks) that broke into pieces during backhoe operations; and a hard, darker icy surface that had to be scraped to provide particulate materials for sampling (Snow White). Here, we use spectra from Phoenix's Surface Stereo Imager (SSI) and a non-linear mixing model with ice and soil components to determine the ice to soil ratio of the ices exposed at the Phoenix landing site. We find Dodo-Goldilocks consists of almost pure water ice. The darker icy material contains ~30 wt% ice (~55 vol%), indicating that it probably formed as pore ice between grains of soil. We conclude that these two types of ice represent two different emplacement mechanisms and periods of deposition. Snow White ice was probably deposited via vapor diffusion from the atmosphere. Dodo-Goldilocks ice was probably deposited through an ice-lens or needle ice mechanism. Buried snow or glacial ice is unlikely for Dodo-Goldilocks, given its restricted spatial extent and the fact that the site is covered by large rocks.

  19. A design study for the isolation of the 281-3H retention basin at the Savannah River Site using the viscous liquid barrier technology

    Energy Technology Data Exchange (ETDEWEB)

    Moridis, G.J.; Persoff, P.; Apps, J.; James, A.; Oldenburg, C.; McGrath, A.; Myer, L.; Pellerin, L.; Pruess, K. [Lawrence Berkeley National Lab., CA (United States). Earth Sciences Div.

    1996-11-01

    This report is a description of the design study for a pilot-scale field demonstration of the Viscous Liquid Barrier (VLB) technology, a new subsurface containment technology for waste isolation using a new generation of barrier liquids. The demonstration site was Retention Basin 281-3H, a shallow catchment basin at the Savannah River Site, which is contaminated mainly by radionuclides ({sup 137}Cs, {sup 90}Sr, and {sup 238}Pu). The goals of the field demonstration were (a) to demonstrate the ability to create a continuous subsurface barrier in order to isolate the contaminants, and (b) to demonstrate the continuity, performance, and integrity of the barrier. The site was characterized, and preliminary hydraulic conductivity data were obtained from core samples. Based on the site characteristics and the functional requirements, a conceptual model was developed, the barrier specifications were defined, and lance injection was selected as the emplacement method. The injection strategy for the subsurface conditions at the site was determined using numerical simulations. An appropriate variant of Colloidal Silica (CS) was selected as the barrier liquid based on its relative insensitivity to interactions with the site soils, and the formulation for optimum site performance was determined. A barrier verification strategy, including hydraulic, pneumatic, tracer, and geophysical methods, was developed. A lance water injection test was conducted in order to obtain representative estimates of the hydraulic conductivity and its distribution for the design of the barrier emplacement. The water injection test demonstrated the lack of permeable zones for CS injection, and a decision not to proceed with the barrier emplacement was reached.

  20. Barriers to screening mammography.

    Science.gov (United States)

    Sarma, Elizabeth A

    2015-01-01

    Breast cancer (BRCA) is the second most commonly diagnosed cancer among women in the USA, and mammography is an effective means for the early detection of BRCA. Identifying the barriers to screening mammography can inform research, policy and practice aiming to increase mammography adherence. A literature review was conducted to determine common barriers to screening mammography adherence. PsycINFO and PubMed databases were searched to identify studies published between 2000 and 2012 that examined barriers associated with reduced mammography adherence. Three thematic groups of barriers, based on social ecology, were identified from the literature: healthcare system-level, social and individual-level barriers. Researchers must consider screening behaviour in context and, therefore, should simultaneously consider each level of barriers when attempting to understand screening behaviour and create interventions to increase mammography adherence.

  1. Paleomagnetic evidence for low-temperature emplacement of the phreatomagmatic Peperino Albano ignimbrite (Colli Albani volcano, Central Italy)

    Science.gov (United States)

    Porreca, M.; Mattei, M.; Macniocaill, C.; Giordano, G.; McClelland, E.; Funiciello, R.

    2008-05-01

    The Peperino Albano (approximately 19-36 ka old) is a phreatomagmatic pyroclastic flow deposit, cropping out along the slopes of the associated Albano maar (Colli Albani volcano, Italy). The deposit exhibits lateral and vertical transitions from valley pond to veneer facies, as well as intracrater facies. We present the results of a paleomagnetic study of thermal remanent magnetization (TRM) of the lithic clasts of the Peperino Albano ignimbrite that provide quantitative estimates of the range of emplacement temperatures across the different facies of the ignimbrite. Emplacement temperatures estimated for the Peperino Albano ignimbrite range between 240° and 350°C, with the temperatures defined in the intracrater facies being generally lower than in the valley pond and veneer facies. This is possibly due to the large size of the sampled clasts in the intracrater facies which, when coupled with low temperature at the vent, were not completely heated throughout their volume during emplacement. The emplacement temperatures derived from the paleomagnetic results are in good agreement with the presence of un-burnt plants at the base of the ignimbrite, indicating that the temperature of the pyroclastic flow was lower than the temperature of ignition of wood. Paleomagnetic results from the Peperino Albano confirm the reliability of the paleomagnetic approach in defining the thermal history of pyroclastic flow deposits.

  2. Study of the Emplacement Mechanism of the Fenghuangshan Granite Pluton and Related Cu-Au Mineralization in Tongling, Anhui Province

    Institute of Scientific and Technical Information of China (English)

    WU Ganguo; ZHANG Da; LI Dongxu; ZHANG Xiangxin; SHAO Yongjun; ZANG Wenshuan; WANG Qunfeng

    2004-01-01

    The Fenghuangshan Pluton is located in the Tongling polymineral-cluster district in the middle-lower section of the Yangtze metallogenic belt. In tectonic terms, it is in the middle of the Guichi-Fanchang faulted fold bundle of the lower Yangtze Platform fold belt between the Dabie Orogenic Belt and the Jiangnan Massif. Analyses of the structural deformation characteristics of both the contact zone and the interior of the pluton are used to explain its emplacement mechanism. The foliation and lineation of the pluton, consisting of the oriented distribution of dark minerals and xenoliths, mainly concentrate along the margin of the pluton. Toward the center of the pluton, the foliation structure becomes weak, showing intense compression formation at the margin, and reflecting the conformable intrusion of the pluton. The relatively gentle lineation is evidence of a rotatory emplacement mechanism. Relatively steep marginal foliation reflects compression expanding. Affected by the thermal power of the pluton, the metamorphism of the contact zone has zonation. Both the strike of the axial plane of fold at the contact zone and that of the flow cleavage of the ductile shear zone are consistent with the boundary of the pluton, which reflects the speciality of conformable intrusion. The hinges of the folds are mostly inclined and erect, reflecting both the rotation of the pluton and its upward spiraling emplacement mechanism. Boudins developed in both the contact zone and the steep strata indicate the emplacement characteristic of the ballon expanding. The surrounding rock of the contact zone shortens horizontally. The average percentage of shortening is 39.7%, which further proves the mechanism of the pluton expanding, and the space occupied by the active expanding intrusion was provided by the shortening of the surrounding rock. The left-lateral shear shown by the ductile shear zone and the rheomorphic fold reveals that the pluton emplacement and the deformation of

  3. Forceful Emplacement of Granitic Plutons in an Extensional Tectonic Setting: Syn-kinematic Plutons in the Yagan-Onch Hayrhan Metamorphic Core Complex

    Institute of Scientific and Technical Information of China (English)

    王涛; 郑亚东; 李天兵; 高永军; 马铭波

    2002-01-01

    It is generally considered that granitic plutons are forcefully emplaced in a compressional setting and permissively emplaced in an extensional setting. This paper, however, shows that syn-kinematic (extensional) elliptic granitic plutons in the Yagan-Onch Hayrhan metamorphic core complex (MCC) have relatively strong forceful emplacement, which are indicated by (1) concentric distribution of the rock units, (2) a strain pattern with strong strains on the margins and low strains at the centre of a pluton, and particularly (3) syn-emplacement shortening of the host rocks within the aureole. The strain analysis for the host rocks shows that the host-rock ductile shortening, I.e. Forceful emplacement, provides about 16?24% of the emplacement space for the present plutons. All these suggest that forceful emplacement occurs not only in a compressional tectonic setting, but also in an extensional setting. This study further demonstrates the significance of the multiple emplacement of granitic plutons and provides new information about the causality between granitic magmatism and the formation of the MCC and its dynamics.

  4. Modelling dune erosion, overwash and inundation of barrier islands

    NARCIS (Netherlands)

    Hoonhout, B.; Thiel de Vries, J.S.M.

    2012-01-01

    Physical model experiments are performed at Deltares to investigate the morphological response of barrier islands on extreme storm events. The experiments included dune erosion, overwash and inundation regimes. Extensive measurement techniques made detailed comparison with numerical models possible.

  5. Converse Barrier Certificate Theorems

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2016-01-01

    This paper shows that a barrier certificate exists for any safe dynamical system. Specifically, we prove converse barrier certificate theorems for a class of structurally stable dynamical systems. Other authors have developed a related result by assuming that the dynamical system has neither sing...

  6. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  7. Photogrammetric and Global Positioning System Measurements of Active Pahoehoe Lava Lobe Emplacement on Kilauea, Hawaii

    Science.gov (United States)

    Hamilton, Christopher W.; Glaze, Lori S.; James, Mike R.; Baloga, Stephen M.; Fagents, Sarah A.

    2012-01-01

    Basalt is the most common rock type on the surface of terrestrial bodies throughout the solar system and -- by total volume and areal coverage -- pahoehoe flows are the most abundant form of basaltic lava in subaerial and submarine environments on Earth. A detailed understanding of pahoehoe emplacement processes is necessary for developing accurate models of flow field development, assessing hazards associated with active lava flows, and interpreting the significance of lava flow morphology on Earth and other planetary bodies. Here, we examine the active emplacement of pahoehoe lobes along the margins of the Hook Flow from Pu'u 'O'o on Kilauea, Hawaii. Topographic data were acquired between 21 and 23 February 2006 using stereo-imaging and differential global positing system (DGPS) measurements. During this time, the average discharge rate for the Hook Flow was 0.01-0.05 cubic m/s. Using stereogrammetric point clouds and interpolated digital terrain models (DTMs), active flow fronts were digitized at 1 minute intervals. These areal spreading maps show that the lava lobe grew by a series of breakouts tha t broadly fit into two categories: narrow (0.2-0.6 m-wide) toes that grew preferentially down-slope, and broad (1.4-3.5 m-wide) breakouts that formed along the sides of the lobe, nearly perpendicular to the down-flow axis. These lobes inflated to half of their final thickness within approx 5 minutes, with a rate of inflation that generally deceased with time. Through a combination of down-slope and cross-slope breakouts, lobes developed a parabolic cross-sectional shape within tens of minutes. We also observed that while the average local discharge rate for the lobe was generally constant at 0.0064 +/- 0.0019 cubic m/s, there was a 2 to 6 fold increase in the areal coverage rate every 4.1 +/- 0.6 minutes. We attribute this periodicity to the time required for the dynamic pressurization of the liquid core of the lava lobe to exceed the cooling-induced strength of the

  8. Skin barrier function

    DEFF Research Database (Denmark)

    2016-01-01

    Renowned experts present the latest knowledge Although a very fragile structure, the skin barrier is probably one of the most important organs of the body. Inward/out it is responsible for body integrity and outward/in for keeping microbes, chemicals, and allergens from penetrating the skin. Since...... the role of barrier integrity in atopic dermatitis and the relationship to filaggrin mutations was discovered a decade ago, research focus has been on the skin barrier, and numerous new publications have become available. This book is an interdisciplinary update offering a wide range of information...... on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...

  9. Felsic lavas of Terceira Island, Azores: distribution, morphology and mode of emplacement

    Science.gov (United States)

    Pimentel, Adriano

    2010-05-01

    Terceira Island in the Azores archipelago is a remarkable example of effusive felsic volcanism. It is located in a geodynamic setting dominated by the WNW-ESE slow-spreading Terceira Rift that separates the Eurasian and Nubia plates, east of the Mid-Atlantic Ridge. Terceira differs from the other islands of the archipelago for the abundance of peralkaline felsic domes and coulees, which are the product with the largest volumetric expression (4.1 km3 DRE) in the recent eruptive history of the island (Morphological, morphometric and geological analysis provided the means to constraint the emplacement modes of these peralkaline felsic lavas. From the spatial distribution of the eruptive centres it was possible to determine the presence of extensive WNW-ESE, NW-SE and ENE-WSW alignments, suggesting that these lavas were fed from depth by dykes strongly influenced by regional stress fields, although sometimes locally subjugated by magmatic stress. Lavas from both volcanoes are peralkaline trachytes and comendites very uniform in appearance with black, scoriaceous, rubbly surfaces, ranging from almost aphyric to porphyritic. They show surface morphologies typical of viscous magmas such as ogive-like rigdes, convex in the direction of flow, high levees, lava channels and spines. The lava domes are 14-183 m in height, with radius of 50-372 m, ranging in volume from 7x104 to 4x107 m3. Coulees can reach lengths in excess of 2800 m, with widths ranging from 110 to 900 m and thicknesses of 15-70 m. The calculated volumes range from about 3x105 to 108 m3. The morphometric analysis indicate that domes follow a geometrical growth pattern of low domes (H = 0,36R), dominated essentially by an endogenous regime, although exogenous growth involving extrusions of small lobes is also present. This suggests a low magma viscosity at time of extrusion, compatible with the yield strengths (3x104 - 7x105 Pa) and plastic viscosities (3x107 - 7x1010 Pa.s) estimated and the peralkaline nature

  10. Volcanic debris avalanche transport and emplacement: water content and fragmentation vs disaggregation

    Science.gov (United States)

    Roverato, Matteo

    2016-04-01

    Volcanic Debris Avalanches are voluminous, heterogeneous mass-flows of poorly sorted sediments (micron - 10's m) that move downslope under the effect of gravity. They travel with extremely high velocity for long distances with very potential high destructive power. These flows may reach initial velocities as high as 100m/s, travel for several tens of kilometers, and spread over broad sectors. They are commonly considered as inertial dry grain flows where particle-particle interaction can be within a frictional and/or collisional regime. It is largely assumed that fragmentation of particles within a debris avalanche occurs primarily at the moment of the edifice failure, due to sudden material decompression and dilation. Following failure, the dislodged mass starts to slide or glide downslope, and progressive disaggregation begins. Only minimal fragmentation is thought to occur during flow due to grain-grain contact. Thus, the main process responsible for generating an interclast matrix during transport is the disaggregation of already fractured clasts and megaclasts, particularly those that are already diamictons. However, data obtained from the Pungarehu volcanic debris avalanche deposit (VDAD) illustrate that fragmentation of intact rock may also occur during debris avalanche motion and through collisional and frictional grain-grain contacts experienced during long-runout flow. More, depending on their water and clay content, these granular and block-sliding flows may transform into a debris flow with distance from source, changing completely their flow behaviour and enhancing their run-out and hazard impacts. Pungarehu VDAD (ca. 25 Ka cal.) was emplaced by the largest known collapse of the Taranaki volcano (New Zealand) occurred near the Last Glacial Maximum (LGM), with snow and ice cover, fluids circulation, hydrothermal alteration and substantial groundwater present. This VDAD appears to encompass a range of flow behaviour from proximal unsaturated and unmixed

  11. Morpho-tectonics and mechanism of emplacement of the andesitic ring in Givshad, east of Iran

    Science.gov (United States)

    Khatib, M. M.; Zarrinkoub, M. H.

    2009-04-01

    Givshad compersional-sinestral shear zone in south of Baghran mountain range in south of Birjand, east of Iran, is one of the main phenomena that has been important in evolution of magmatism in nothern part of Sistan sutur zone. This zone with north-south active right lateral strike-slip faulting occurs along the eastern margin of the Lut block in the East Iranian mountain ranges, which roughly define the eastern border of Iran. The rocks within the East Iranian ranges define the Sistan Suture zone. This deformed accretionary prism was emplaced during the destruction in late Cretaceous (senomanian) to Paleocene times (89 to 55 Ma) of a narrow arm of Neo-Tethys ocean separating the structurally coherent Lut and Afghan continental blocks. The suture zone is composed of two accretionary prisms (the Neh and Ratuk complexes) separated by sediments and volcanics of the Sefidabeh fore-arc basin. The Neh and Ratuk complexes are identifiably separate structural units, the former dating from late Cretaceous (senomanian) to Eocene times( 89 to 34 Ma), and the latter from the pre-Mastrichtian Cretaceous (>71Ma), with different over-all composition and structural histories. The rock units dip steeply, and strike NW_SE. there have been three phases of deformation. The earliest folding event produced E-W trending structures which were subsequently re-folded along NNW trending axial surfaces and dissected by conjugate left- and right-lateral strike-slip faults. These two deformation episodes occurred between the Late Eocene and Early Miocene. The third on-going, deformation event involves N-S right lateral strike slip faulting and associated folding and is probably related to the final closure of Arabia and Eurasia. The Sistan suture zone runs N-S along the eastern margin of Iran. This is a melange of ophiolitic and deep sea rocks. Several apparently active fault strands can be traced running N-S through the suture zone. The andsitic ring-like structures in Givshad have been a

  12. Thermal impact of waste emplacement and surface cooling associated with geologic disposal of nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.S.Y.; Mangold, D.C.; Spencer, R.K.; Tsang, C.F.

    1982-08-01

    The thermal effects associated with the emplacement of aged radioactive wastes in a geologic repository were studied, with emphasis on the following subjects: the waste characteristics, repository structure, and rock properties controlling the thermally induced effects; the current knowledge of the thermal, thermomechanical, and thermohydrologic impacts, determined mainly on the basis of previous studies that assume 10-year-old wastes; the thermal criteria used to determine the repository waste loading densities; and the technical advantages and disadvantages of surface cooling of the wastes prior to disposal as a means of mitigating the thermal impacts. The waste loading densities determined by repository designs for 10-year-old wastes are extended to older wastes using the near-field thermomechanical criteria based on room stability considerations. Also discussed are the effects of long surface cooling periods determined on the basis of far-field thermomechanical and thermohydrologic considerations. The extension of the surface cooling period from 10 years to longer periods can lower the near-field thermal impact but have only modest long-term effects for spent fuel. More significant long-term effects can be achieved by surface cooling of reprocessed high-level waste.

  13. Evaluation of Sulfur Flow Emplacement on Io from Galileo Data and Numerical Modeling

    Science.gov (United States)

    Williams, David A.; Greeley, Ronald; Lopes, Rosaly M. C.; Davies, Ashley G.

    2001-01-01

    Galileo images of bright lava flows surrounding Emakong Patera have bee0 analyzed and numerical modeling has been performed to assess whether these flows could have resulted from the emplacement of sulfur lavas on Io. Images from the solid-state imaging (SSI) camera show that these bright, white to yellow Emakong flows are up to 370 km long and contain dark, sinuous features that are interpreted to be lava conduits, -300-500 m wide and >lo0 km lorig. Neiu-Infrared Mapping S estimate of 344 K f 60 G131'C) within the Bmakong caldera. We suggest that these bright flows likely resulted from either sulfur lavas or silicate lavas that have undergone extensive cooling, pyroclastic mantling, and/or alteration with bright sulfurous materials. The Emakoag bright flows have estimated volume of -250-350 km', similar to some of the smaller Columbia River Basalt flows, If the Emakong flows did result from effusive sulfur eruptions, then they are orders of magnitude reater in volume than any terrestrial sulfur flows. Our numerical modeling capable of traveling tens to hundreds of kilometers, consistent with the predictions of Sagan. Our modeled flow distances are also consistent with the measured lengths of the Emakong channels and bright flows.

  14. Emplacement age and tectonic implications of the Xilinhot A-type granite in Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    SHI Guanghai; MIAO Laicheng; ZHANG Fuqing; JIAN Ping; FAN Weiming; LIU Dunyi

    2004-01-01

    A new rock type of granite, approximate 45 km2 in area and located about 10 km south of Xilinhot, Inner Mongolia, was found in the Sunitezuoqi (or called Suzuoqi)-Xilinhot tectonic belt and identified as an A-type mia- rolitic intrusion. The pluton has miarolitic structure and is composed chiefly of perthite, quartz, euhedral albite and potassium feldspar. Various types of textures occur in the pluton, such as perthitie, graphic and myrmekite textures. Only quartz is found in miarolitic cavity. This A-type granite with seagull-shaped REE patterns and obvious negative Eu anomaly (δEu = 0.24-0.28) is high in SiO2 (76%-77%), K and Na (Na2O + K2O = 7.75%-8.15%) and low in Ca (CaO = 0.20%-0.22%), Fe and Mg. Both petrographical observations and chemical compositions indicate that it is an A-type granite. Zircon SHRIMP U-Pb analyses indicate that this A-type granite was emplaced at 276 ( 2 Ma and coeval with the same type of granites in the adjacent areas. Therefore, it suggests that this pluton was likely formed in a post-orogenic extensional setting and probably related to break-off of subducted slabs in Central Asian Orogenic Belt (CAOB), which indicate that the Sunitezuoqi-Xilinhot belt was tectonically evolved into post-orogenic stage since early Permian.

  15. Reaction weakening and emplacement of crystalline thrusts: Diffusion control on reaction rate and strain rate

    Science.gov (United States)

    O'Hara, Kieran

    2007-08-01

    In the southern Appalachians, the Blue Ridge-Piedmont crystalline thrust sheet was emplaced onto low-grade Late Precambrian and Paleozoic sedimentary rocks in the footwall along a basal detachment consisting of phyllosilicate-rich mylonites (phyllonites). The phyllonites developed first by mechanical breakdown of feldspar followed by chemical breakdown to white mica in the presence of a pore fluid. Diffusion of solute in the pore fluid is the rate limiting step in controlling reaction rate and also the strain rate. Assuming solute diffusion follows the Stokes-Einstein equation, the shear strain rate is given by ⅆγ/ⅆt=2ωkT/5ηrx for shear stress ≥20 MPa, where n is a constant, ω is a geometric factor, k is Boltzmann's constant, T is absolute temperature, η is water viscosity, r is the atomic radius of the diffusing species, and x is the diffusion distance. A bulk diffusion coefficient in the range of ˜10 -10 to 10 -12 m 2/s over distances of 10-100 m results in strain rates of 10 -14 to 10 -13 s -1 in the temperature range 200-400 °C. It is concluded that greenschist grade crystalline thrust sheets develop on pre-existing basement faults that become weak during reaction softening and localize into high strain phyllonite zones in which pore fluid diffusion controls reaction rate and strain rate.

  16. Recycler barrier RF buckets

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab

    2011-03-01

    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  17. Quarter-scale modeling of room convergence effects on CH (contact-handled) TRU drum waste emplacements using WIPP (Waste Isolation Pilot Plant) reference design geometries

    Energy Technology Data Exchange (ETDEWEB)

    VandeKraats, J.

    1987-11-01

    This study investigates the effect of horizontal room convergence on CH waste packages emplaced in the WIPP Reference Design geometry (rooms 13 feet high by 33 feet wide, with minus 3/8 inch screened backfill emplaced over and around the waste packages) as a function of time. Based on two tests, predictions were made with regard to full-scale 6-packs emplaced in the Reference Design geometry. These are that load will be transmitted completely through the stack within the first five years after waste emplacement and all drums in all 6-packs will be affected; that virtually all drums will show some deformation eight years after emplacement; that some drums may breach before the eighth year after emplacement has elapsed; and that based on criteria developed during testing, it is predicted that 1% of the drums emplaced will be breached after 8 years and, after 15 years, approximately 12% of the drums are predicted to be breached. 8 refs., 41 figs., 3 tabs.

  18. Barriers to Effective Listening.

    Science.gov (United States)

    Hulbert, Jack E.

    1989-01-01

    Discusses the following barriers which interfere with listening efficiency: content, speaker, medium, distractions, mindset, language, listening speed, and feedback. Suggests ways to combat these obstacles to accurate comprehension. (MM)

  19. [Vascular endothelial Barrier Function].

    Science.gov (United States)

    Ivanov, A N; Puchinyan, D M; Norkin, I A

    2015-01-01

    Endothelium is an important regulator of selective permeability of the vascular wall for different molecules and cells. This review summarizes current data on endothelial barrier function. Endothelial glycocalyx structure, its function and role in the molecular transport and leukocytes migration across the endothelial barrier are discussed. The mechanisms of transcellular transport of macromolecules and cell migration through endothelial cells are reviewed. Special section of this article addresses the structure and function of tight and adherens endothelial junction, as well as their importance for the regulation of paracellular transport across the endothelial barrier. Particular attention is paid to the signaling mechanism of endothelial barrier function regulation and the factors that influence on the vascular permeability.

  20. LARGE BOULDERS ALONG THE RABAT COAST (MOROCCO; POSSIBLE EMPLACEMENT BY THE NOVEMBER, 1st, 1755 A.D. TSUNAMI

    Directory of Open Access Journals (Sweden)

    Nadia Mhammdi, Fida Medina

    2008-01-01

    Full Text Available The rocky coastline south of Rabat (Morocco shows a large number of boulders lying upon the lithified dune system. The boulders, of 4-100 tons, may be single, in imbricated sets, or forming clusters and ridges. Several of the boulders were lifted and overturned, thus showing pool apertures downwards. Transport distance is generally decametric because of the surface roughness, but it can reach 300 m in flat areas. All boulders have been detached from their initial position at the fractured front of the active cliff. Quantification with the help wave hydrodynamics and rock displacement mechanics shows that dislodgement and transport of these boulders were accomplished rather by tsunami than by storm waves. Although no dating was attempted, post- emplacement bio-erosion by littorinids and the absence of any erosional features below the boulders suggests that they were emplaced during the 1st November 1755 AD Lisbon tsunami.

  1. Emplacement of Amba Dongar Carbonatite-alkaline Complex at Cretaceous/Tertiary Boundary: Evidence from 40Ar-39Ar Chronology

    Indian Academy of Sciences (India)

    Jyotiranjan S Ray; Kanchan Pande; T R Venkatesan

    2000-03-01

    40Ar-39Ar analyses of three fresh alkaline rock samples and a phlogopite separate from a carbonatite from Amba Dongar carbonatite-alkaline complex of the Deccan Flood Basalt Province, India, yield indistinguishable precise plateau ages of 64.8 ± 0.6, 64.7 ± 0.5, 65.5 ± 0.8 and 65.3 ± 0.6 Ma, giving a mean plateau age of 65.0 ± 0.3 Ma, which is the age of emplacement of this complex. This age implies contemporaneity of Amba Dongar with several other carbonatite-alkaline activities of Chhota Udaipur subprovince and is consistent with their Reunion-Deccan plume origin hypothesis. The emplacement of these complexes at 65 Ma makes them very significant in the ongoing debate on the K/T extinctions owing to their capacity to rapidly inject a substantial amount of CO2 and SO2 into the atmosphere.

  2. Therapeutic experiences of community gardens: putting flow in its place.

    Science.gov (United States)

    Pitt, Hannah

    2014-05-01

    This paper develops the concept of therapeutic place experiences by considering the role of activity. Research of community gardening finds that particular tasks are therapeutic and exhibit the characteristics of flow, but those who lack influence over their community gardening are less likely to benefit from flow as their sense of control is reduced. The notion of emplaced flow is proposed to locate individual experiences amongst socio-spatial factors which limit self-determinacy and therefore affect wellbeing. Emplacing flow prompts critical reflection on who is excluded from therapeutic place experiences, and whether sites offering momentary escape have an enduring impact on wellbeing.

  3. Magnetic fabrics in characterization of magma emplacement and tectonic evolution of the Moyar Shear Zone, South India

    Directory of Open Access Journals (Sweden)

    P. Pratheesh

    2013-01-01

    Full Text Available The Moyar Shear Zone (MSZ of the South Indian granulite terrain hosts a prominent syenite pluton (∼560 Ma and associated NW-SE to NE-SW trending mafic dyke swarm (∼65 Ma and 95 Ma. Preliminary magnetic fabric studies in the mafic dykes, using Anisotropy of Magnetic Susceptibly (AMS studies at low-field, indicate successive emplacement and variable magma flow direction. Magnetic lineation and foliation in these dykes are identical to the mesoscopic fabrics in MSZ mylonites, indicating shear zone guided emplacement. Spatial distribution of magnetic lineation in the dykes suggests a common conduit from which the source magma has been migrated. The magnetic foliation trajectories have a sigmoidal shape to the north of the pluton and curve into the MSZ suggesting dextral sense of shear. Identical fabric conditions for magnetic fabrics in the syenite pluton and measured field fabrics in mylonite indicate syntectonic emplacement along the Proterozoic crustal scale dextral shear zone with repeated reactivation history.

  4. Lava tubes from the Paraná-Etendeka Continental Flood Basalt Province: Morphology and importance to emplacement models

    Science.gov (United States)

    Waichel, Breno L.; Tratz, Eliza B.; Pietrobelli, Gisele; Jerram, Dougal A.; Calixto, Geovane R.; Bacha, Rafael R.; Tomazzolli, Edison R.; da Silva, Wellington B.

    2013-12-01

    Lava tubes are a common feature in active volcanic areas around the world. They are related to pahoehoe and 'a'ā lava flow fields, that are predominantly basaltic, and form as the most efficient mechanism to transport lava in insulated fedder pathways. Continental Flood Basalt Provinces (CFBs) are thick volcanic sequences of predominantly basaltic lava flows and flow fields, which cover huge areas and are often related to continental breakup. The proposed emplacement model for CFB's is synonymous with the inflation processes observed in modern active flows. Although pahoehoe and 'a'ā lava flows are recognized in CFB's provinces, good examples of lava tubes, pipes or tube systems are rarely reported. Lava feeder systems (tube/pipes) are a common feature of modern pahoehoe flow systems so it would be expected to find good examples in CFB's provinces formed by the same emplacement processes. Here we describe the morphology of two lava tube systems discovered in the Paraná CFB Province in Southern Brazil. Comparisons are made with active systems and the importance of CFB lava tube systems, and their recognition in the rock record, are discussed in the context of the current emplacement model.

  5. Emplacement time of the Loe-Shilman carbonatite from NW Pakistan: Constraints from fission-track dating

    Energy Technology Data Exchange (ETDEWEB)

    Khattak, N.U. [National Centre of Excellence in Geology, University of Peshawar (Pakistan)], E-mail: nimat_khattak@yahoo.com; Akram, M. [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Khan, M.A. [National Centre of Excellence in Geology, University of Peshawar (Pakistan); Khan, H.A. [COMSATS Headquarters, 4th Floor, Shahrah-e-Jamhuriat, G-5/2 Islamabad 44000 (Pakistan)

    2008-08-15

    The Loe-Shilman carbonatite complex is situated in the extreme west of the Peshawar Plain Alkaline Igneous Province (PAIP), near the Pakistan-Afghanistan border. It comprises sill-form bodies emplaced along an E-W trending and N dipping fault zone in Paleozoic to Precambrian metasedimentary rocks of Khyber Agency. Fission-track dating studies on the apatite crystals using the external detector method and age standard approach (the {zeta} method) yielded an age of 30.0{+-}1.5Ma for the Loe-Shilman carbonatite. Close agreement between the previously determined radiometric ages from the same as well as the neighboring carbonatite complexes of the PAIP and the fission-track apatite age of this study indicates that the Loe-Shilman carbonatite was emplaced at relatively shallow crustal level and quickly cooled to low temperatures (<60{sup 0}C) required for the complete retention of fission tracks in apatite and that the fission-track age of this study is the emplacement age of the Loe-Shilman carbonatite.

  6. Tracking lava flow emplacement on the east rift zone of Kilauea, Hawai’i with synthetic aperture radar (SAR) coherence

    Science.gov (United States)

    Dietterich, Hannah R.; Poland, Michael P.; Schmidt, David; Cashman, Katharine V.; Sherrod, David R.; Espinosa, Arkin Tapia

    2012-01-01

    Lava flow mapping is both an essential component of volcano monitoring and a valuable tool for investigating lava flow behavior. Although maps are traditionally created through field surveys, remote sensing allows an extraordinary view of active lava flows while avoiding the difficulties of mapping on location. Synthetic aperture radar (SAR) imagery, in particular, can detect changes in a flow field by comparing two images collected at different times with SAR coherence. New lava flows radically alter the scattering properties of the surface, making the radar signal decorrelated in SAR coherence images. We describe a new technique, SAR Coherence Mapping (SCM), to map lava flows automatically from coherence images independent of look angle or satellite path. We use this approach to map lava flow emplacement during the Pu‘u ‘Ō‘ō-Kupaianaha eruption at Kīlauea, Hawai‘i. The resulting flow maps correspond well with field mapping and better resolve the internal structure of surface flows, as well as the locations of active flow paths. However, the SCM technique is only moderately successful at mapping flows that enter vegetation, which is also often decorrelated between successive SAR images. Along with measurements of planform morphology, we are able to show that the length of time a flow stays decorrelated after initial emplacement is linearly related to the flow thickness. Finally, we use interferograms obtained after flow surfaces become correlated to show that persistent decorrelation is caused by post-emplacement flow subsidence.

  7. The emplacement of the Peridotite Nappe of New Caledonia and its bearing on the tectonics of obduction

    Science.gov (United States)

    Gautier, Pierre; Quesnel, Benoît; Boulvais, Philippe; Cathelineau, Michel

    2016-12-01

    The Peridotite Nappe of New Caledonia is one of the few ophiolites worldwide that escaped collisional orogeny after obduction. Here we describe the deformation associated with serpentinization in two klippes of the nappe in northwestern New Caledonia. The klippes are flat lying and involve S/SW vergent reverse-slip shear zones which are true compressional structures in origin. Further northeast, the nappe is folded in association with the development of a steep schistosity in low-grade metasediments. This difference in structural style indicates that the Peridotite Nappe experienced compression at greater depths toward its root zone, suggesting a "push from the rear" mechanism of emplacement. This supports the view that the nappe has been emplaced through horizontal contraction sustained by plate convergence. We establish a crustal-scale cross section at the end of the obduction event, before Neogene extension. This involves a large fold nappe of high-pressure rocks bounded from below by a major thrust. Furthermore, we show that obduction in New Caledonia occurred through dextral oblique convergence. Oblique convergence probably resulted from the initial obliquity between the subduction trench and the continental ribbon that became incorporated in it. This obliquity can solve the paradox of the Peridotite Nappe seemingly being emplaced at the same time the high-pressure rocks were exhumed. Oblique convergence together with focused erosional denudation on the northeastern flank of the island led to exhumation of the metamorphic rocks in a steep fold nappe rising through the rear part of the orogen.

  8. Post-emplacement melt-flow as a feasible mechanism for reversed differentiation in tholeiitic sills

    Science.gov (United States)

    Aarnes, I.; Podladchikov, Y. Y.; Neumann, E.-R.; Galerne, C.

    2009-04-01

    This study provides a new explanation model for differentiation in sills, using a combination of geochemical data and field observations, numerical modeling and dimensional analysis. Geochemical data from a saucer-shaped dolerite sill intruded into the Karoo basin, South Africa reveal a process which causes reversed differentiation. The differentiation process is identified by D-shaped geochemical profiles. The notation is based on the vertical expression of whole-rock Mg-number (Mg# = 100*Mg/(Mg+Fetotal)) with the most primitive composition (i.e. high Mg#) in its center, and progressively more evolved composition (i.e. low Mg#) towards the upper and lower margins. Normal differentiation by fractional crystallization is known to produce C-shaped profiles (in terms of Mg# variations), as for example in the Skaergaard Intrusion. From a detailed field study of a saucer-shaped sill complex in the Karoo Basin, South Africa, we observe several different shapes (e.g. S, D and I) occurring within one sill. However, the C-shape is practically absent and hence fractional crystallization with double layer diffusion cannot be the main mechanism for differentiation in sheet intrusions. Several models have been proposed for the formation of D-shaped profiles, such as crystal settling and convection, multiple injections, flow differentiation, compositional convection, or Soret fractionation in combination with in situ crystallization. There is however no general agreement of one particular model, as they pose difficulties explaining all occurrences of D-shaped profiles. Based on numerical modeling we introduce post-emplacement flow as a feasible mechanism to explain the D-shaped profiles. A melt-flow can cause magmatic differentiation in the sill by transporting incompatible and less compatible elements associated with the melt phase (e.g. Zr and Fe) in an advective process through a stationary crystal network. Crystal networks of considerable strength are known to form in the

  9. Processes accompanying of mantle plume emplacement into continental lithosphere: Evidence from NW Arabian plate, Western Syria

    Science.gov (United States)

    Sharkov, E. V.

    2015-12-01

    Lower crustal xenoliths occurred in the Middle Cretaceous lamprophyre diatremes in Jabel Ansaria (Western Syria) (Sharkov et al., 1992). They are represented mainly garnet granulites and eclogite-like rocks, which underwent by deformations and retrograde metamorphism, and younger fresh pegmatoid garnet-kaersutite-clinopyroxene (Al-Ti augite) rocks; mantle peridotites are absent in these populations. According to mineralogical geothermobarometers, forming of garnet-granulite suite rocks occurred under pressure 13.5-15.4 kbar (depths 45-54 kn) and temperature 965-1115oC. At the same time, among populations of mantle xenoliths in the Late Cenozoic platobasalts of the region, quite the contrary, lower crustal xenoliths are absent, however, predominated spinel lherzolites (fragments of upper cooled rim of a plume head), derived from the close depths (30-40 km: Sharkov, Bogatikov, 2015). From this follows that ancient continental crust was existed here even in the Middle Cretaceous, but in the Late Cenozoic was removed by extended mantle plume head; at that upper sialic crust was not involved in geomechanic processes, because Precambrian metamorphic rocks survived as a basement for Cambrian to Cenozoic sedimentary cover of Arabian platform. In other words, though cardinal rebuilding of deep-seated structure of the region occurred in the Late Cenozoic but it did not affect on the upper shell of the ancient lithosphere. Because composition of mantle xenolithis in basalts is practically similar worldwide, we suggest that deep-seated processes are analogous also. As emplacement of the mantle plume heads accompanied by powerful basaltic magmatism, very likely that range of lower (mafic) continental crust existence is very convenient for extension of plume heads and their adiabatic melting. If such level, because of whatever reasons, was not reached, melting was limited but appeared excess of volatile matters which led to forming of lamprophyre or even kimberlite.

  10. Structural control on basaltic dike and sill emplacement, Paiute Ridge mafic intrusion complex, southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Carter Krogh, K.E.; Valentine, G.A.

    1996-08-01

    Late Miocene basaltic sills and dikes in the Paiute Ridge area of southern nevada show evidence that their emplacement was structurally controlled. Basaltic dikes in this area formed by dilating pre-existing vertical to steeply E-dipping normal faults. Magma propagation along these faults must have required less energy than the creation of a self-propagated fracture at dike tips and the magma pressure must have been greater than the compressive stress perpendicular to the fault surface. N- to NE-trending en echelon dikes formed locally and are not obviously attached to the three main dikes in the area. The en echelon segments are probably pieces of deeper dikes, which are segmented perhaps as a result of a documented rotation of the regional stresses. Alternatively, changes in orientation of principal stresses in the vicinity of each en echelon dike could have resulted from local loads associated with paleotopographic highs or nearby structures. Sills locally branched off some dikes within 300 m of the paleosurface. These subhorizontal bodies occur consistently in the hanging wall block of the dike-injected faults, and intrude Tertiary tuffs near the Paleozoic-Tertiary contact. The authors suggest that the change in stresses near the earth`s surface, the material strength of the tuff and paleozoic rocks, and the Paleozoic bedding dip direction probably controlled the location of sill formation and direction of sill propagation. The two largest sills deflected the overlying tuffs to form lopoliths, indicating that the magma pressure exceeded vertical stresses at that location and that the shallow level and large size of the sills allowed interaction with the free (earth`s) surface. 32 refs., 4 figs., 1 tab.

  11. Fluid flow and reactive transport around potential nuclear waste emplacement tunnels at Yucca Mountain, Nevada.

    Science.gov (United States)

    Spycher, N F; Sonnenthal, E L; Apps, J A

    2003-01-01

    The evolution of fluid chemistry and mineral alteration around a potential waste emplacement tunnel (drift) is evaluated using numerical modeling. The model considers the flow of water, gas, and heat, plus reactions between minerals, CO(2) gas, and aqueous species, and porosity-permeability-capillary pressure coupling for a dual permeability (fractures and matrix) medium. Two possible operating temperature modes are investigated: a "high-temperature" case with temperatures exceeding the boiling point of water for several hundred years, and a "low-temperature" case with temperatures remaining below boiling for the entire life of the repository. In both cases, possible seepage waters are characterized by dilute to moderate salinities and mildly alkaline pH values. These trends in fluid composition and mineral alteration are controlled by various coupled mechanisms. For example, upon heating and boiling, CO(2) exsolution from pore waters raises pH and causes calcite precipitation. In condensation zones, this CO(2) redissolves, resulting in a decrease in pH that causes calcite dissolution and enhances feldspar alteration to clays. Heat also enhances dissolution of wall rock minerals leading to elevated silica concentrations. Amorphous silica precipitates through evaporative concentration caused by boiling in the high-temperature case, but does not precipitate in the low-temperature case. Some alteration of feldspars to clays and zeolites is predicted in the high-temperature case. In both cases, calcite precipitates when percolating waters are heated near the drift. The predicted porosity decrease around drifts in the high-temperature case (several percent of the fracture volume) is larger by at least one order of magnitude than in the low temperature case. Although there are important differences between the two investigated temperature modes in the predicted evolution of fluid compositions and mineral alteration around drifts, these differences are largely within to

  12. Eruption and emplacement timescales of ignimbrite super-eruptions from thermo-kinetics of glass shards

    Directory of Open Access Journals (Sweden)

    Yan eLavallée

    2015-02-01

    Full Text Available Super-eruptions generating hundreds of cubic kilometres of pyroclastic density currents are commonly recorded by thick, welded and lava-like ignimbrites. Despite the huge environmental impact inferred for this type of eruption, little is yet known about the timescales of deposition and post-depositional flow. Without these timescales, the critical question of the duration of any environmental impact, and the ensuing gravity of its effects for the Earth system, eludes us. The eruption and welding of ignimbrites requires three transects of the glass transition. Magma needs to: 1 fragment during ascent, 2 liquefy and relax during deposition, agglutination and welding (sintering, and 3 quench by cooling into the glassy state. Here we show that welding is a rapid, syn-depositional process and that the welded ignimbrite sheet may flow for up to a few hours before passing through the glass transition a final time. Geospeedometry reveals that the basal vitrophyre of the Grey’s Landing ignimbrite underwent the glass transition at a rate of ~0.1 °C.min^-1 at 870 °C; that is, 30-180 °C below pre-eruptive geothermometric estimates. Application of a 1-D cooling model constrains the timescale of deposition, agglutination, and welding of the basal vitrophyre to less than 1 hour, and possibly even tens of minutes. Thermo-mechanical iteration of the sintering process indicates an optimal temperature solution for the emplacement of the vitrophyres at 966 °C. The vitrophyres reveal a Newtonian rheology up to 46 MPa, which suggests that the ash particles annealed entirely during welding and that viscous energy dissipation is unlikely from loading conditions alone, unless shear stresses imposed by the overlying ash flow were excessively high and sustained over long distances. The findings underline the value of the term 'lava-like' flow to describe the end rheology of Snake River-type ignimbrites, fully consistent with the typical lithofacies observed.

  13. Emplacement and erosive effects of the south Kasei Valles lava on Mars

    Science.gov (United States)

    Dundas, Colin M.; Keszthelyi, Laszlo P.

    2014-01-01

    Although it has generally been accepted that the Martian outflow channels were carved by floods of water, observations of large channels on Venus and Mercury demonstrate that lava flows can cause substantial erosion. Recent observations of large lava flows within outflow channels on Mars have revived discussion of the hypothesis that the Martian channels are also produced by lava. An excellent example is found in south Kasei Valles (SKV), where the most recent major event was emplacement of a large lava flow. Calculations using high-resolution Digital Terrain Models (DTMs) demonstrate that this flow was locally turbulent, similar to a previously described flood lava flow in Athabasca Valles. The modeled peak local flux of approximately 106 m3 s−1 was approximately an order of magnitude lower than that in Athabasca, which may be due to distance from the vent. Fluxes close to 107 m3 s−1 are estimated in some reaches but these values are probably records of local surges caused by a dam-breach event within the flow. The SKV lava was locally erosive and likely caused significant (kilometer-scale) headwall retreat at several cataracts with tens to hundreds of meters of relief. However, in other places the net effect of the flow was unambiguously aggradational, and these are more representative of most of the flow. The larger outflow channels have lengths of thousands of kilometers and incision of a kilometer or more. Therefore, lava flows comparable to the SKV flow did not carve the major Martian outflow channels, although the SKV flow was among the largest and highest-flux lava flows known in the Solar System.

  14. Bulk arc strain, crustal thickening, magma emplacement, and mass balances in the Mesozoic Sierra Nevada arc

    Science.gov (United States)

    Cao, Wenrong; Paterson, Scott; Saleeby, Jason; Zalunardo, Sean

    2016-03-01

    Quantifying crustal deformation is important for evaluating mass balance, material transfer, and the interplay between tectonism and magmatism in continental arcs. We present a dataset of >650 finite strain analyses compiled from published works and our own studies with associated structural, geochronologic, and geobarometric information in central and southern Sierra Nevada, California, to quantify the arc crust deformation. Our results show that Mesozoic tectonism results in 65% arc-perpendicular bulk crust shortening under a more or less plane strain condition. Mesozoic arc magmatism replaced ∼80% of this actively deforming arc crust with plutons requiring significantly greater crustal thickening. We suggest that by ∼85 Ma, the arc crust thickness was ∼80 km with a 30-km-thick arc root, resulting in a ∼5 km elevation. Most tectonic shortening and magma emplacement must be accommodated by downward displacements of crustal materials into growing crustal roots at the estimated downward transfer rate of 2-13 km/Myr. The downward transfer of crustal materials must occur in active magma channels, or in "escape channels" in between solidified plutons that decrease in size with time and depth resulting in an increase in the intensity of constrictional strain with depth. We argue that both tectonism and magmatism control the thickness of the crust and surface elevation with slight modification by surface erosion. The downward transported crustal materials initially fertilize the MASH zone thus enhancing to the generation of additional magmas. As the crustal root grows it may potentially pinch out and cool the mantle wedge and thus cause reduction of arc magmatism.

  15. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    R. Jarek

    2005-08-29

    The purpose of this model report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The resulting seepage evaporation and gas abstraction models are used in the total system performance assessment for the license application (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2005 [DIRS 173782], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports. To be consistent with other project documents that address features, events, and processes (FEPs), Table 6.14.1 of the current report includes updates to FEP numbers and FEP subjects for two FEPs identified in the technical work plan (TWP) governing this report (BSC 2005 [DIRS 173782]). FEP 2.1.09.06.0A (Reduction-oxidation potential in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.06.0B (Reduction-oxidation potential in Drifts; see Table 6.14-1). FEP 2.1.09.07.0A (Reaction kinetics in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.07.0B (Reaction kinetics in Drifts; see Table 6.14-1). These deviations from the TWP are justified because they improve integration with FEPs

  16. Hedging Double Barriers with Singles

    NARCIS (Netherlands)

    Sbuelz, A.

    2000-01-01

    Double barrier options provide risk managers with good-deal flexibility in tailoring portfolio returns.Their hedges offer full protection only if unwound along the barriers.This work provides non-dynamic hedges that project the risk of double barriers on to single barriers.Non-dynamic hedges overcom

  17. Functions of an engineered barrier system for a nuclear waste repository in basalt

    Energy Technology Data Exchange (ETDEWEB)

    Coons, W.E.; Moore, E.L.; Smith, M.J.; Kaser, J.D.

    1980-01-01

    Defined in this document are the functions of components selected for an engineered barrier system for a nuclear waste repository in basalt. The definitions provide a focal point for barrier material research and development by delineating the purpose and operative lifetime of each component of the engineered system. A five-component system (comprised of waste form, canister, buffer, overpack, and tailored backfill) is discussed in terms of effective operation throughout the course of repository history, recognizing that the emplacement environment changes with time. While components of the system are mutually supporting, redundancy is provided by subsystems of physical and chemical barriers which act in concert with the geology to provide a formidable barrier to transport of hazardous materials to the biosphere. The operating philosophy of the conceptual engineered barrier system is clarified by examples pertinent to storage in basalt, and a technical approach to barrier design and material selection is proposed. A method for system validation and qualification is also included which considers performance criteria proposed by external agencies in conjunction with site-specific models and risk assessment to define acceptable levels of system performance.

  18. On the Traversal Time of Barriers

    Science.gov (United States)

    Aichmann, Horst; Nimtz, Günter

    2014-06-01

    Fifty years ago Hartman studied the barrier transmission time of wave packets (J Appl Phys 33:3427-3433, 1962). He was inspired by the tunneling experiments across thin insulating layers at that time. For opaque barriers he calculated faster than light propagation and a transmission time independent of barrier length, which is called the Hartman effect. A faster than light (FTL or superluminal) wave packet velocity was deduced in analog tunneling experiments with microwaves and with infrared light thirty years later. Recently, the conjectured zero time of electron tunneling was claimed to have been observed in ionizing helium inside the barrier. The calculated and measured short tunneling time arises at the barrier front. This tunneling time was found to be universal for elastic fields as well as for electromagnetic fields. Remarkable is that the delay time is the same for the reflected and the transmitted waves in the case of symmetric barriers. Several theoretical physicists predicted this strange nature of the tunneling process. However, even with this background many members of the physics community do not accept a FTL signal velocity interpretation of the experimental tunneling results. Instead a luminal front velocity was calculated to explain the FTL experimental results frequently. However, Brillouin stated in his book on wave propagation and group velocity that the front velocity is given by the group velocity of wave packets in the case of physical signals, which have only finite frequency bandwidths. Some studies assumed barriers to be cavities and the observed tunneling time does represent the cavity lifetime. We are going to discus these continuing misleading interpretations, which are found in journals and in textbooks till today.

  19. Message maps for safety barrier awareness

    DEFF Research Database (Denmark)

    Jørgensen, Kirsten; Duijm, Nijs Jan; Troen, Hanne

    2011-01-01

    All people are exposed to risks in everyday life, but they seldom experience accidents. Therefore, people often believe that these accidents will never happen, and they do not see the risks. By increasing the ability to notice risks, to see safety barriers, and to assess the safety barriers’ perf...

  20. Barriers to learning from incidents and accidents

    NARCIS (Netherlands)

    Dechy, N.; Dien, Y.; Drupsteen, L.; Felicio, A.; Cunha, C.; Roed-Larsen, S.; Marsden, E.; Tulonen, T.; Stoop, J.; Strucic, M.; Vetere Arellano, A.L.; Vorm, J.K.J. van der; Benner, L.

    2015-01-01

    This document provides an overview of knowledge concerning barriers to learning from incidents and accidents. It focuses on learning from accident investigations, public inquiries and operational experience feedback, in industrial sectors that are exposed to major accident hazards. The document disc

  1. Subduction initiation, recycling of Alboran lower crust, and intracrustal emplacement of subcontinental lithospheric mantle in the Westernmost Mediterranean

    Science.gov (United States)

    Varas-Reus, María Isabel; Garrido, Carlos J.; Bosch, Delphine; Marchesi, Claudio; Hidas, Károly; Booth-Rea, Guillermo; Acosta-Vigil, Antonio

    2015-04-01

    Unraveling the tectonic settings and processes involved in the annihilation of subcontinental mantle lithosphere is of paramount importance for our understanding of the endurance of continents through Earth history. Unlike ophiolites -- their oceanic mantle lithosphere counterparts -- the mechanisms of emplacement of the subcontinental mantle lithosphere in orogens is still poorly known. The emplacement of subcontinental lithospheric mantle peridotites is often attributed to extension in rifted passive margins or continental backarc basins, accretionary processes in subduction zones, or some combination of these processes. One of the most prominent features of the westernmost Mediterranean Alpine orogenic arcs is the presence of the largest outcrops worldwide of diamond facies, subcontinental mantle peridotite massifs; unveiling the mechanisms of emplacement of these massifs may provide important clues on processes involved in the destruction of continents. The western Mediterranean underwent a complex Alpine evolution of subduction initiation, slab fragmentation, and rollback within a context of slow convergence of Africa and Europe In the westernmost Mediterranean, the alpine orogeny ends in the Gibraltar tight arc, which is bounded by the Betic, Rif and Tell belts that surround the Alboran and Algero-Balearic basins. The internal units of these belts are mostly constituted of an allochthonous lithospheric domain that collided and overthrusted Mesozoic and Tertiary sedimentary rocks of the Mesozoic-Paleogene, South Iberian and Maghrebian rifted continental paleomargins. Subcontinental lithospheric peridotite massifs are intercalated between polymetamorphic internal units of the Betic (Ronda, Ojen and Carratraca massifs), Rif (Beni Bousera), and Tell belts. In the Betic chain, the internal zones of the allochthonous Alboran domain include, from bottom to top, polymetamorphic rock of the Alpujarride and Malaguide complexes. The Ronda peridotite massif -- the

  2. Lucky Strike seamount: Implications for the emplacement and rifting of segment-centered volcanoes at slow spreading mid-ocean ridges

    Science.gov (United States)

    Escartín, J.; Soule, S. A.; Cannat, M.; Fornari, D. J.; Düşünür, D.; Garcia, R.

    2014-11-01

    history of emplacement, tectonic evolution, and dismemberment of a central volcano within the rift valley of the slow spreading Mid-Atlantic Ridge at the Lucky Strike Segment is deduced using near-bottom sidescan sonar imagery and visual observations. Volcano emplacement is rapid (spreading may eventually split it. At Lucky Strike, this results in two modes of crustal construction. Eruptions and tectonic activity focus at a narrow graben that bisects the central volcano and contains the youngest lava flows, accumulating a thick layer of extrusives. Away from the volcano summit, deformation and volcanic emplacement is distributed throughout the rift valley floor, lacking a clear locus of accretion and deformation. Volcanic emplacement on the rift floor is characterized by axial volcanic ridges fed by dikes that propagate from the central axial magma chamber. The mode of rapid volcano construction and subsequent rifting observed at the Lucky Strike seamount is common at other central volcanoes along the global mid-ocean ridge system.

  3. Career Barriers and Coping Efficacy among Native American Students

    Science.gov (United States)

    Thompson, Mindi N.

    2013-01-01

    This study examined the relationship between career barriers (low perceived social status [PSS], experiences with personal and systemic classism, and general ethnic discrimination) and college outcome expectations (COEs) among a sample of 121 Native American postsecondary students. Self-efficacy for coping with career barriers was tested as a…

  4. Sustained-Release Permanganate: Passive Reactive Barriers for Green and Sustainable Remediation

    Science.gov (United States)

    Dugan, P. J.

    2011-12-01

    Reactive materials in permeable reactive barriers (PRBs) have proven very useful for transforming or destroying organic waste in situ. Once emplaced they typically do not require a continued supply of electrical power and have the added benefit of creating a reactive zone for the destruction of contaminants in place. Controlled-release techniques have been utilized extensively in diverse fields such as pharmaceutical and agrochemical technologies. However, controlled- and sustained release of an oxidant during in situ chemical oxidation (ISCO) is an emerging concept that is extremely relevant to the field of environmental remediation, yet to-date has received little attention. ISCO using the oxidants permanganate, persulfate, and catalyzed hydrogen peroxide has shown great promise for remediation of many recalcitrant organic contaminants of concern (COC). Because the oxidant also reacts with natural organic matter, inorganic soil constituents, and other reduced compounds, the presence of a protective barrier that controls oxidant release may enhance the efficiency of ISCO and allow for long-term low-cost treatment of chlorinated solvents. To this end, sustained-release permanganate (SRP) was developed. Paraffin wax was used as the environmentally benign and biodegradable matrix material for encapsulating the solid potassium permanganate (KMnO4) particles. The paraffin matrix protects the solid KMnO4 particles from fast dissolution and potentially undesirable nonproductive reactions. The SRP material contains between 60%-80% permanganate and can be formed as candles for direct push applications in reactive barriers, or chipped material for hydro-fracturing into low permeability media. One-dimensional (1-D) SRP column experiments were conducted to evaluate permanganate release behavior using deionized (DI) water as the influent or COC removal efficiency using dissolved trichloroethene (TCE) as the influent. The influent dissolved TCE concentrations were 1 mg/L and

  5. Barriers to cancer screening.

    Science.gov (United States)

    Womeodu, R J; Bailey, J E

    1996-01-01

    Many barriers to cancer screening have been summarized and discussed. Barriers have been documented in all patient populations, but some groups such as ethnic minorities and the elderly face unique barriers. The barriers to cancer screening, are multifactorial, but much of the responsibility for change must lie with health care providers and the health care delivery industry. This is not to free the patient of all responsibility, but some significant barriers are beyond their direct control. Take, for example, socioeconomic status, disease knowledge, and culturally related perceptions and myths about cancer detection and treatment. The health care industry must do a better job identifying and overcoming these barriers. The significant effects of provider counseling and advice must not be underestimated. Patients must first be advised, and then further actions must be taken if they reject the screening advice. Did they refuse adherence to recommendations because they do not view themselves as susceptible, because of overwhelming personal barriers, or because of a fatalistic attitude toward cancer detection and treatment? If that is the case, physicians and health care institutions must attempt to change perceptions, educate, and personalize the message so that patients accept their disease susceptibility [table: see text]. Multiple patient and provider risk factors have been identified that can be used to target patients particularly at high risk for inadequate cancer screening and providers at high risk for performing inadequate screening. Research has clearly demonstrated the effectiveness of interventions to improve tracking of patient and physician compliance with screening recommendations. Further research is needed to show the impact of managed-care penetration and payer status on screening efforts, and incentive schemes need to be tested that reward institutions and third-party payers who develop uniform standards and procedures for cancer screening. The

  6. Syn and post- emplacement transformations of the Misti (Peru) volcanic debris avalanches into lahars

    Science.gov (United States)

    Bernard, K.; Van Wyk de Vries, B.; Thouret, J.

    2012-12-01

    We identify stratigraphic, sedimentological and structural variations in lithofacies of debris-avalanche deposits from El Misti volcano in the Quebrada San Lazaro and Río Chili Valley, near the city of Arequipa (south Peru), to determine lithofacies transformations. We describe the internal process associated to the external conditions acting on debris-avalanche deposits in order to assess stages of transformations from the proximal to distal debris-avalanche deposits and the associated epiclastic deposits. Syn-emplacement transformations inside the volcanic debris-avalanche deposits in the upper course of the Rio Chili Valley: within a few meters, the proximal block facies of the sheared debris-avalanche deposit is transformed at the contact of the ash-rich alluvial deposits in thick units comprising a strongly sheared base of the deposit, then stratified matrix dominated beds with normally sorted boulders aligned with the beds. This is interpreted as the effect of strong shearing inside the confined and proximal debris avalanche during motion, which generated a localised stretching near the base of the deposit and the bulking of the thin water saturated basal layers: the bearing capacity of the matrix debris- avalanche is modified, the block facies has been transformed in a stratified matrix facies. The transformations by bulking along a strong sheared contact contribute to reduce the run-out distance of the debris avalanches in the Río Chili valley. Post-deposition evolutions of the debris-avalanche deposits in the Quebrada San Lazaro: in the upper course of the valley, the landslides in the debris- avalanche deposits related to water circulation destabilise the covering scree and volcanic colluvium dipping at 70°. The fragmentation and sorting due to gravity and water are the external processes which separate matrix and block elements; This is the first stage of transformation. The remobilisation of these separated fractions into lahars transforms this

  7. Continued investigations of the occurrence of water in Pahute Mesa emplacement holes

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, R.L.; Brikowski, T.H.

    1995-04-01

    Periodically, water has been observed in emplacement boreholes drilled for underground testing of nuclear weapons at Pahute Mesa, Nevada Test Site, and is often at levels elevated above the predicted local water table. Water which may provide a means to transport residual radionuclides away from weapon tests may originate as fluids introduced during drilling, from naturally perched groundwater draining into the borehole, or from penetration of the local groundwater table. Lithium-bromide (Li-Br) tracer is being used to evaluate both the origin and movement of these borehole waters. The drilling fluid used to drill the final 100 meters of borehole U-19bh was chemically labeled with LiBr tracer. Lack of significant increase in borehole Br inventory over time indicates that standing water in U-9bh is not returned drilling fluid. Possible sources for the standing water are drilling fluid infiltrated above the bottom 100 in or natural water from a perched or shallower-than-expected saturated zone. The minimum detectable Darcy velocity of water passing through U-19bh is 0.3 m/yr. Borehole U-19bk has a water level approximately 50 in above the predicted pre-drilling water level. Initial water samples were collected from U-19bk to characterize the borehole water quality prior to adding the tracer. The major-ion analytical results of U-19bk along with historical water quality analyses of Water Well 20 and water well UE-19c show that all three waters are similar in character and therefore the water in U-19bk may be either residual drilling fluids originating from Water Well 20 and UE-19c or naturally occurring Pahute Mesa groundwater. LiBr tracer was added to the U-19bk borehole and samples for tracer analysis were collected one month later. For the one month period, no detectable loss of Br was observed. Over this short time period, the minimum detectable Darcy velocity is 10.6 m/yr.

  8. Effects of recharge wells and flow barriers on seawater intrusion.

    Science.gov (United States)

    Luyun, Roger; Momii, Kazuro; Nakagawa, Kei

    2011-01-01

    The installation of recharge wells and subsurface flow barriers are among several strategies proposed to control seawater intrusion on coastal groundwater systems. In this study, we performed laboratory-scale experiments and numerical simulations to determine the effects of the location and application of recharge wells, and of the location and penetration depth of flow barriers, on controlling seawater intrusion in unconfined coastal aquifers. We also compared the experimental results with existing analytical solutions. Our results showed that more effective saltwater repulsion is achieved when the recharge water is injected at the toe of the saltwater wedge. Point injection yields about the same repulsion compared with line injection from a screened well for the same recharge rate. Results for flow barriers showed that more effective saltwater repulsion is achieved with deeper barrier penetration and with barriers located closer to the coast. When the flow barrier is installed inland from the original toe position however, saltwater intrusion increases with deeper barrier penetration. Saltwater repulsion due to flow barrier installation was found to be linearly related to horizontal barrier location and a polynomial function of the barrier penetration depth.

  9. Engineered Barrier System Degradation, Flow, and Transport Process Model Report

    Energy Technology Data Exchange (ETDEWEB)

    E.L. Hardin

    2000-07-17

    The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II).

  10. Emplaced writing figuring as a manifestation of an ecocentric mindset in the narrative art of Petra Müller

    Directory of Open Access Journals (Sweden)

    Susan Meyer

    2014-06-01

    Full Text Available The human-earth connection is a sustained theme in Petra Müller’s oeuvre. The article focuses on this connection as reflected in her narrative art, specifically in accounts that have an autobiographical proclivity. The aim of this article is to outline the nature-centred disposition of Müller’s narrative art in a more definite sense. This is achieved by paying attention to the manner in which the author (the ‘I’ in accounts where the narrator can be identified as the author herself becomes part of the natural environment – whether on a sensory, an emotive, or an intellectual level – where she finds herself and the way she responds to it. At the core of the investigation are the ways in which this reactive engagement is manifested in Müller’s prose work by the implied author and the technique ofemplaced writing. Emplaced writing, a concept created by Linda Russo, was integrated by Susan Smith with Lawrence Buell’s concept of emplacement. This term refers to the technique allowing an active awareness of self and the place physically occupied by the author, as well as how that body fits into this place, to find expression. A broader perspective and greater appreciation of Müller’s work are drawn from the insight into how her close coexistence with the earth is reflected in her narrative art by means of the technique of emplaced writing which is explored in this article as it gives voice to a strong ecocentric disposition.

  11. Barrier mechanisms in the Drosophila blood-brain barrier

    OpenAIRE

    Samantha Jane Hindle; Roland Jerome Bainton

    2014-01-01

    The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated funct...

  12. Emplacement conditions of the c. 1,600-year bp Collier Cone lava flow, Oregon: a LiDAR investigation

    Science.gov (United States)

    Deardorff, Nicholas D.; Cashman, Katharine V.

    2012-11-01

    A long-standing question in lava flow studies has been how to infer emplacement conditions from information preserved in solidified flows. From a hazards perspective, volumetric flux (effusion rate) is the parameter of most interest for open-channel lava flows, as the effusion rate is important for estimating the final flow length, the rate of flow advance, and the eruption duration. The relationship between effusion rate, flow length, and flow advance rate is fairly well constrained for basaltic lava flows, where there are abundant recent examples for calibration. Less is known about flows of intermediate compositions (basaltic andesite to andesite), which are less frequent and where field measurements are limited by the large block sizes and the topographic relief of the flows. Here, we demonstrate ways in which high-resolution digital topography obtained using Light Detection and Ranging (LiDAR) systems can provide access to terrains where field measurements are difficult or impossible to collect. We map blocky lava flow units using LiDAR-generated bare earth digital terrain models (DTMs) of the Collier Cone lava flow in the central Oregon Cascades. We also develop methods using geographic information systems to extract and quantify morphologic features such as channel width, flow width, flow thickness, and slope. Morphometric data are then analyzed to estimate both effusion rates and emplacement times for the lava flow field. Our data indicate that most of the flow outline (which comprises the earliest, and most voluminous, flow unit) can be well explained by an average volumetric flux ˜14-18 m3/s; channel data suggest an average flux ˜3 m3/s for a later, channel-filling, flow unit. When combined with estimates of flow volume, these data suggest that the Collier Cone lava flow was most likely emplaced over a time scale of several months. This example illustrates ways in which high-resolution DTMs can be used to extract and analyze morphologic measurements and

  13. Emplacement mechanism of gravity flows inferred from high resolution Lidar data: The 1944 Somma Vesuvius lava flow (Italy)

    Science.gov (United States)

    Ventura, Guido; Vilardo, Giuseppe

    2008-03-01

    A Digital Terrain Model derived from high resolution Lidar data allows the determination of the morphometric and physical parameters of a lava flow erupted from the Somma-Vesuvius volcano in 1944. The downstream variation of morphometric parameters including slope, aspect, relative relief, thickness, width, and cross sectional area is analyzed, and the changes in viscosity, velocity and flow rate are estimated. The aims of the analyses are to recognize different flow surfaces, to reconstruct the flow kinematics, and to obtain information on the mechanism of emplacement. The results indicate that the 1944 lava flow can be divided in three sectors: a near vent sector (NVS) characterized by a toe-like surface, an intermediate sector (IS) with an 'a'ātype brittle surface, and a distal sector (DS) with a sheet-like ductile surface. Lateral leveés and channels do not occur in NVS, whereas they are well developed in IS. In DS, leveés increase with an increasing distance from the vent. Fold-like surfaces occur in NVS and DS, reflecting local shortening processes due to a decrease in the slope of the substratum and overflows from the main channel. IS and DS emplaced between March 18 and 21, 1944, whereas NVS emplaced on March 19 and partly covered IS. The morphometric and physical parameters indicate that IS moved in a 'tube'-like regime, whereas DS emplaced in a 'mobile crust' regime. The IS to DS transition is marked by an increase in velocity and the flow rate, and by a decrease in thickness, width, cross sectional area, and viscosity. This transition is due to an abrupt increase in the slope of the substratum. The estimated velocity values are in good agreement with the measurements during the 1944 eruption. The analysis used here may be extended to other lava flows. Some gravity flows (debris/mud flows, floods, and avalanches) have rheological properties and shapes similar to those of lavas, and the same process-form relationships may apply to these flows. The

  14. Vertical barriers with increased sorption capacities

    Energy Technology Data Exchange (ETDEWEB)

    Bradl, H.B. [Bilfinger + Berger Bauaktiengesellschaft, Mannheim (Germany)

    1997-12-31

    Vertical barriers are commonly used for the containment of contaminated areas. Due to the very small permeability of the barrier material which is usually in the order of magnitude of 10-10 m/s or less the advective contaminant transport can be more or less neglected. Nevertheless, there will always be a diffusive contaminant transport through the barrier which is caused by the concentration gradient. Investigations have been made to increase the sorption capacity of the barrier material by adding substances such as organoclays, zeolites, inorganic oxides and fly ashes. The contaminants taken into account where heavy metals (Pb) and for organic contaminants Toluole and Phenantrene. The paper presents results of model calculations and experiments. As a result, barrier materials can be designed {open_quotes}tailor-made{close_quotes} depending on the individual contaminant range of each site (e.g. landfills, gasworks etc.). The parameters relevant for construction such as rheological properties, compressive strength and permeability are not affected by the addition of the sorbents.

  15. Dating Kaali Crater (Estonia) based on charcoal emplaced within proximal ejecta blanket

    Science.gov (United States)

    Losiak, Anna; Wild, Eva Maria; Huber, Matthew S.; Wisniowski, Tomasz; Paavel, Kristiina; Jõeleht, Argo; Välja, Rudolf; Plado, Jüri; Kriiska, Aivar; Wilk, Jakob; Zanetti, Michael; Geppert, Wolf D.; Kulkov, Alexander; Steier, Peter; Pirkovic, Irena

    2015-04-01

    The Kaali impact field consists of nine identified craters located on the Saaremaa Island in Estonia. The largest crater is 110 m in diameter (centered around 58°22'21.94"N, 22°40'09.91" E). It was formed by impact of an IAB iron meteoroid into Silurian dolomite target rocks covered by up to a few meters of glacial till (Veski et al. 2007). The age of the Kaali impact structure is still a matter of debate, and the estimates provided by different authors vary considerably between ~6400 BC (Raukas et al. 1995, Moora et al. 2012) and ~400 BC (Rasmussen et al. 2000, Veski et al. 2001). These ages were derived by 14C dating of marker horizons, characterized by a slightly elevated iridium content within the nearby Piila bog yielding a calibrated age of 800-400 BC (Rasmussen et al. 2000, Veski et al. 2001) and occurrences of glassy siliceous material in the Piila bog (~6400 BC: Raukas et al. 1995) or iron microspherules in an organic-rich layer of the Reo gravel pit (6400 BC: Moora et al. 2012). However, the source of the foreign material within those layers was never unequivocally connected with the Kaali crater. 14C dating of material from post-impact organic sediments within Kaali impact craters yielded ages between 1800-1500 BC (Saarse et al. 1991, Veski et al. 2004) and 1450-400 BC (Aaloe et al. 1963). These dates underestimate the age of impact as organic sediments within the crater started to form at unknown period after the impact. On the other hand, Veski et al. (2004) suggested a reservoir effect that might have caused artificially "aging" of the organic matter because the crater was emplaced within Silurian dolomite which is rich in old carbon. The aim of this study is to determine the age of the Kaali crater by 14C dating of organic material covered by the continuous layer of proximal ejecta. This research was conducted in conjunction with a new structural investigation of Kaali Main (Zanetti et al. 2015). Ten samples collected from different locations

  16. Coupling Seepage and Radionuclide Transport in and Around Emplacement Drifts at Yucca Mountain

    Science.gov (United States)

    Zhang, G.; Spycher, N.; Sonnenthal, E.; Steefel, C.

    2007-12-01

    The proposed nuclear waste repository of the United States is located at Yucca Mountain, Nevada. Waste packages will be placed in deep (~350 m) underground drifts in volcanic tuff. Seepage may potentially occur at the repository drifts when the drifts get rewetted after a dryout period. The potential seepage water will be quickly evaporated or boiled to near dryness as long as it falls on the top of the hot waste package leading to formation of brine, precipitation of salts and volatilization of gases. These processes may potentially impact the long-term safety of waste packages in the drift. The objectives of this study are to: (1) develop a quantitative model of coupled thermal, hydrological, and chemical (THC) processes potentially leading to brine formation, salt precipitation and gas volatilization on top of waste packages and/or a drip shield and (2) dynamically integrate such a model into the larger-scale models of processes within and around waste emplacement drifts, as well as into the smaller-scale waste-package corrosion models. Process models were implemented into an existing reactive transport numerical simulator, TOUGHREACT, to allow modeling of (1) evaporative concentration to very high ionic strength (up to 40 molal), (2) boiling point elevation due to dissolved salts, (3) boiling/evaporation to dryness, and (4) salt deliquescence. An integrated near-field and in-drift THC simulation was run using a vertical 2-D grid extending from near the ground surface to the groundwater table, and covering a width equal to half the design drift spacing of 81 m. The integrated model was then used to simulate a discrete dripping event within the drift. The model considered the release of radionuclides into seepage water as this water contacts the waste package and flows through the invert. The precipitation of uranophane and Np-uranophane was also considered. These minerals form in the invert from the neutralization of mildly acidic seepage water by clay minerals

  17. Expectations of barriers to psychosocial care : Views of parents and adolescents in the community

    NARCIS (Netherlands)

    Nanninga, Marieke; Reijneveld, Sijmen A; Knorth, Erik J; Jansen, Danielle E M C

    2016-01-01

    Parents with a child suffering from psychosocial problems frequently experience barriers to psychosocial care, which may hinder access. Expectations of barriers may have the same effect, but evidence is lacking. The aim of this study is to examine parents' and adolescents' expectations of barriers r

  18. Reduction of air pollution levels downwind of a road with an upwind noise barrier

    Science.gov (United States)

    Enayati Ahangar, Faraz; Heist, David; Perry, Steven; Venkatram, Akula

    2017-04-01

    We propose a dispersion model to estimate the impact of a solid noise barrier upwind of a highway on air pollution concentrations downwind of the road. The model, based on data from wind tunnel experiments conducted by Heist et al. (2009), assumes that the upwind barrier has two main effects: 1) it creates a recirculation zone behind the barrier that sweeps the emissions from the highway back towards the wall, and 2) it enhances vertical dispersion and initial mixing. By combining the upwind barrier model with the mixed wake model for a downwind barrier described in Schulte et al. (2014), we are able to model dispersion of emissions from a highway with noise barriers on both sides. The model provides a good description of measurements made in the wind tunnel. The presence of an upwind barrier causes reductions in concentrations relative to those measured downwind of a road with no barriers. The reduction can be as large as that caused by a downwind barrier if the recirculation zone covers the width of the highway. Barriers on both sides of the highway result in larger reductions downwind of the barriers than those caused by a single barrier either upwind or downwind. As expected, barrier effects are small beyond 10 barrier heights downwind of the highway. We also propose a tentative model to estimate on-road concentrations within the recirculation zone induced by the upwind barrier.

  19. PRIORITISING LEAN CONSTRUCTION BARRIERS IN UGANDA'S CONSTRUCTION INDUSTRY

    Directory of Open Access Journals (Sweden)

    Henry Mwanaki Alinaitwe

    2009-06-01

    Full Text Available Engaging in lean construction efforts could prove to be highly rewarding for building firms in Uganda. However, lean construction is risky and can be disastrous if not properly managed. Lean production efforts in some other countries have not been successful due to the many barriers to its successful implementation. To enable sound lean construction efforts and to increase the chances of success in eliminating waste, a thorough investigation of the barriers is essential. This study presents 31 barriers and investigates their influence (strength on the success of lean construction initiatives. Structured interviews were carried out with technical managers of building firms to assess their perception of the barriers to lean production based on their experience at their firms. The strongest barrier is the provision of inputs exactly when required. Additionally, the barriers were ranked according to the ease of overcoming each. The easiest barrier to overcome is keeping the required items in the right place. Finally, a graphical aid is provided to enable decision makers to concentrate their efforts on the influential (strong, yet easy to overcome barriers. A lack of buildable designs and a participative management style for the workforce are the most important barriers to successful waste reduction in terms of strength and ease of overcoming. On the other hand, a lack of an organisational culture that supports teamwork, a lack of prefabrication and a lack of knowledgeable and skilled workers are regarded as low in strength, and at the same time difficult to overcome.

  20. Contrasting magmatic structures between small plutons and batholiths emplaced at shallow crustal level (Sierras de Córdoba, Argentina)

    Science.gov (United States)

    Pinotti, Lucio P.; D'Eramo, Fernando J.; Weinberg, Roberto F.; Demartis, Manuel; Tubía, José María; Coniglio, Jorge E.; Radice, Stefania; Maffini, M. Natalia; Aragón, Eugenio

    2016-11-01

    Processes like injection, magma flow and differentiation and influence of the regional strain field are here described and contrasted to shed light on their role in the formation of small plutons and large batholiths their magmatic structures. The final geometric and compositional arrangement of magma bodies are a complex record of their construction and internal flow history. Magma injection, flow and differentiation, as well as regional stresses, all control the internal nature of magma bodies. Large magma bodies emplaced at shallow crustal levels result from the intrusion of multiple magma batches that interact in a variety of ways, depending on internal and external dynamics, and where the early magmatic, growth-related structures are commonly overprinted by subsequent history. In contrast, small plutons emplaced in the brittle-ductile transition more likely preserve growth-related structures, having a relatively simple cooling history and limited internal magma flow. Outcrop-scale magmatic structures in both cases record a rich set of complementary information that can help elucidate their evolution. Large and small granitic bodies of the Sierra Pampeanas preserve excellent exposures of magmatic structures that formed as magmas stepped through different rheological states during pluton growth and solidification. These structures reveal not only the flow pattern inside magma chambers, but also the rheological evolution of magmas in response to temperature evolution.

  1. Effects of the deviation characteristics of nuclear waste emplacement boreholes on borehole liner stresses; Yucca Mountain Project

    Energy Technology Data Exchange (ETDEWEB)

    Glowka, D.A.

    1990-09-01

    This report investigates the effects of borehole deviation on the useability of lined boreholes for the disposal of high-level nuclear waste at the proposed Yucca Mountain Repository in Nevada. Items that lead to constraints on borehole deviation include excessive stresses that could cause liner failure and possible binding of a waste container inside the liner during waste emplacement and retrieval operations. Liner stress models are developed for two general borehole configurations, one for boreholes drilled with a steerable bit and one for boreholes drilled with a non-steerable bit. Procedures are developed for calculating liner stresses that arise both during insertion of the liner into a borehole and during the thermal expansion process that follows waste emplacement. The effects of borehole curvature on the ability of the waste container to pass freely inside the liner without binding are also examined. Based on the results, specifications on borehole deviation allowances are developed for specific vertical and horizontal borehole configurations of current interest. 11 refs., 22 figs., 4 tabs.

  2. Overcoming Biological Barriers with Ultrasound

    Science.gov (United States)

    Thakkar, Dhaval; Gupta, Roohi; Mohan, Praveena; Monson, Kenneth; Rapoport, Natalya

    2011-01-01

    Effect of ultrasound on the permeability of blood vessels and cell membranes to macromolecules and nanodroplets was investigated using mouse carotid arteries and tumor cells. Model macromolecular drug, FITC-dextran with molecular weight of 70,000 Da was used in experiments with carotid arteries. The effect of unfocused 1-MHz ultrasound and and perfluoro-15-crown-5-ether nanodroplets stabilized with the poly(ethylene oxide)-co-poly(D,L-lactide) block copolymer shells was studied. In cell culture experiments, ovarian carcinoma cells and Doxorubicin (DOX) loaded poly(ethylene oxide)-co-polycaprolactone nanodroplets were used. The data showed that the application of ultrasound resulted in permeabilization of all biological barriers tested. Under the action of ultrasound, not only FITC-dextran but also nanodroplets effectively penetrated through the arterial wall; the effect of continuous wave ultrasound was stronger than that of pulsed ultrasound. In cell culture experiments, ultrasound triggered DOX penetration into cell nuclei, presumably due to releasing the drug from the carrier. Detailed mechanisms of the observed effects require further study. PMID:24839333

  3. Barrier mechanisms in the Drosophila blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Samantha Jane Hindle

    2014-12-01

    Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  4. International Expert Review of SRCan: Engineered Barrier Issues. External review contribution in support of SKI's and SSI's review of SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David (Quintessa Limited, Henley-on-Thames (GB)); Bennett, David (TerraSalus Limited, Oakham (GB)); Apted, Mick (Monitor Scientific LLC, Denver, CO (US)); Saellfors, Goeran (Chalmers Univ. of Technology, Goeteborg (SE)); Saario, Timo (VTT Materials and Building (FI)); Segle, Peter (Inspecta, Stockholm (SE))

    2008-03-15

    of uncertainties in SKB's programme and safety reports, some of which relate to issues that appear to be of sufficient significance that they will need to be thoroughly addressed in the SR-Site safety report in time for the repository licence application. Other less urgent issues might be identified in SR-Can as uncertainties to be addressed through an appropriate performance confirmation programme. Performance confirmation may be defined as the programme of tests, experiments and analyses, conducted to evaluate the adequacy of the information used to demonstrate compliance with long-term safety standards for a geological repository. The most significant of the issues identified by the EBS review group include: - Demonstration of the feasibility of EBS emplacement. SKB will need to present more details on the reference EBS design, on its reference repository construction method, and on the specifications for the EBS materials. In particular, SKB still needs to demonstrate satisfactorily that the EBS can be successfully fabricated and emplaced in the appropriate configuration under repository conditions and at the rates that are projected to be required during waste disposal. SKB needs to develop and test quality assurance and quality control procedures for repository construction and operation, including EBS emplacement. SKB also needs to conduct further tests of EBS emplacement, and to characterise the as-emplaced EBS components. More generally, SKB should describe and explain in more detail how its schedule for developing plans and procedures and for conducting laboratory experiments and underground tests relates to the schedules for safety assessment and licensing. - Canister manufacture and integrity. The view of the review group is that SKB should consider a number of issues in greater detail to build further confidence in the proposed approach for canister manufacture and in the assessments of canister integrity and performance. For example, SKB could

  5. Simulation of the interaction of tsunami waves with underwater barriers

    Science.gov (United States)

    Boshenyatov, B. V.; Zhiltsov, K. N.

    2016-10-01

    This article examines the experimental and numerical simulation of the processes of distribution and interaction of tsunami-type gravitational waves with one barrier and a complex of two barriers. Experiments were conducted in a hydrodynamic channel using high-precision sensors for the measurement of the wave processes. Mathematical modelling was carried out using two-dimensional non-stationary Navier-Stokes equations for an incompressible fluid using the freely available software package OpenFOAM. It is shown that for small-amplitude waves, when their advance speed is described by the linear theory of shallow water, the interaction with the underwater barriers has important non-linear and viscous effects. Our results explain why a complex of two barriers spaced at a definite distance from each other has a significant impact on the power of the transmitted wave. The energy of the waves passing through the two barriers can be reduced to 35% of the incident wave.

  6. Pluton emplacement in a releasing bend in a transpressive regime: the arrozal granite in the Paraíba do Sul shear belt, Rio de Janeiro.

    Science.gov (United States)

    Nummer, Alexis R; Machado, Rômulo; Dehler, Nolan M

    2007-06-01

    The Arrozal Granite, situated in the southwestern region of the State of Rio de Janeiro, has a granitic to granodioritic composition. It contains a strong mylonitic foliation along its border, passing gradually to a well-developed magmatic foliation towards its center. Structural analysis indicates that the Arrozal Granite was emplaced along the Além-Paraíba Shear Zone in a dextral transpressive tectonic regime. A regional shift of the trend along this shear zone from NE-SW to E-W, observed in the area, is interpreted to be casually related to the creation of space for the emplacement of the granite. Our data indicate that releasing bends may have played an important role for space generation during the emplacement of the Arrozal Granite and other plutons.

  7. Technical barrier challenges

    Institute of Scientific and Technical Information of China (English)

    李思佳

    2014-01-01

    according to a famouse report,the foreign Technical Barriers to Trade(TBT)have some effects on the exports of the People’s Republic of China.Major findings are as follows:(1)TBT makes it more difficult for China to export;(2)TBT increases the costs of Chinese export commodities;(3)TBT causes friction and confilicts in the international trade;(4)SOME developed countries have moved their phase-outs to China and other developing countries,which have become victims of TBT.

  8. Support or Barrier?

    DEFF Research Database (Denmark)

    Sanden, Guro Refsum; Lønsmann, Dorte

    This study offers a critical look at how corporate-level language management influences front-line language practices among employees in three multinational corporations (MNCs) headquartered in Scandinavia. Based on interview and document data, we examine, firstly, what front-line practices...... employees use to cross language boundaries in their everyday work, and, secondly, how these practices relate to top-down language management in the case companies. Our findings show that employees are often dependent on ad hoc and informal solutions in cross- language situations, which leads us...... to a discussion of how a company’s language policy may be seen as both support and a barrier....

  9. [Barrier methods of contraception].

    Science.gov (United States)

    Goldsmith, A; Edelman, D A

    1982-01-01

    Vaginal methods of contraception were the earliest types used and some references to them date back to antiquity. Most of the vaginal contraceptive agents identified by the ancient Greeks, Indians, Japanese, and Chinese have been found in modern laboratory tests to have spermicidal properties, but it is doubtful that the methods were fully reliable or were used by many people. During the 19th century the condom, vaginal spermicides, and diaphragm became available. The development of nonoxynol-9 and other nonirritating but effective spermicidal agents improved vaginal contraceptives greatly by the 1950s, but starting in the 1960s newer methods began to replace the vaginal methods. Interest in barrier methods has been reawakened somewhat by concern about the health effects of hormonal methods. At present all barrier methods leave something to be desired. Failure rates of 3-30% for barrier methods in general have been estimated, but the higher rates are believed due to incorrect or inconsistent use. Theoretical failure rates of condoms and diaphragms have been estimated at 3/100 women-years, but in actual use failure rates may reach 15 for condoms and 13 for diaphragms used with spermicides. Use-effectiveness rates are greatly influenced by motivation. For a variety of reasons, the acceptability of barrier methods is low, especially in developing countries. New developments in spermicidal agents include sperm inhibitors, which impede the fertilizing capacity of sperm rather than attempting a spermicidal effect; a number of such agents have been studied and have proven more effective in animal tests than conventional spermicides. Neosampoon, a new spermicidal foam, has attracted an increasing number of users, especially in developing countries. A new condom, made of thin polymers and containing a standard dose of nonoxynol-9, has been designed to dissolve in the vaginal fluid. Further studies are needed of its acceptability, efficacy, and side effects before it becomes

  10. The Sondalo gabbro contact aureole (Campo unit, Eastern Alps): implications for mid-crustal mafic magma emplacement

    Science.gov (United States)

    Petri, B.; Mohn, G.; Štípská, P.; Schulmann, K.; Manatschal, G.

    2016-05-01

    Contact aureoles rimming plutonic rocks are the locus of metamorphism and deformations witnessing magma emplacement mechanisms in the crust. In this study, structural and petrological observations are combined to mineral equilibria modelling to unravel the polyphase tectono-metamorphic history of the Permian Sondalo gabbro and its host rock, the Campo unit (Eastern Alps). The Campo unit consists of Grt-St-Ms-Bt-Pl-Qtz ± Sil ± And ± Crd mica schists attesting of a Carboniferous prograde P- T path, reaching 6 kbar/600 °C and subsequently 5.6 kbar/650 °C. This metamorphism is coeval with the formation of a sub-vertical NE-SW trending foliation (S1) and its overprint by a sub-vertical NW-SE trending foliation (S2). The heat brought by the Permian intrusives subsequently caused heating of the Campo unit at around 3-4 kbar/540 °C reflected by regional static crystallization of cordierite and andalusite porphyroblasts. During the intrusion of the Sondalo gabbro, thermal peak conditions are recorded by Grt-Sil-Spl-Crd-Ilm granulitic xenoliths at ~5.5 kbar/930 °C, subsequently exhumed at ~4 kbar during the development of a new foliation (S3). This foliation is localized around the pluton and moderately dips away from the centre of the pluton. In the migmatitic contact aureole, Grt-Sil-Bt-Pl-Qtz-Ilm and Grt-Sil-Crd-Spl-Bt-Kfs-Ilm residual rocks bear the new foliation (S3) and document a decompression from 6 kbar/750 °C to 5 kbar/725 °C and from 5.2 kbar/800 °C to reach 4.8 kbar/770 °C, respectively. The P- T- d paths recorded by the host rock and the xenoliths point to a two-step magma emplacement. First the Sondalo gabbro intruded the Campo unit causing heating of the host rock without deformation at 3-4 kbar. Second, the ductile flow along the pluton margins developed a new foliation (S3) during exhumation of the pluton and its immediate contact aureole from 6 to 4 kbar. Altogether, it indicates a progressive increase in mechanical coupling between the pluton

  11. Control of Precambrian basement deformation zones on emplacement of the Laramide Boulder batholith and Butte mining district, Montana, United States

    Science.gov (United States)

    Berger, Byron R.; Hildenbrand, Thomas G.; O'Neill, J. Michael

    2011-01-01

    What are the roles of deep Precambrian basement deformation zones in the localization of subsequent shallow-crustal deformation zones and magmas? The Paleoproterozoic Great Falls tectonic zone and its included Boulder batholith (Montana, United States) provide an opportunity to examine the importance of inherited deformation fabrics in batholith emplacement and the localization of magmatic-hydrothermal mineral deposits. Northeast-trending deformation fabrics predominate in the Great Falls tectonic zone, which formed during the suturing of Paleoproterozoic and Archean cratonic masses approximately 1,800 mega-annum (Ma). Subsequent Mesoproterozoic to Neoproterozoic deformation fabrics trend northwest. Following Paleozoic through Early Cretaceous sedimentation, a Late Cretaceous fold-and-thrust belt with associated strike-slip faulting developed across the region, wherein some Proterozoic faults localized thrust faulting, while others were reactivated as strike-slip faults. The 81- to 76-Ma Boulder batholith was emplaced along the reactivated central Paleoproterozoic suture in the Great Falls tectonic zone. Early-stage Boulder batholith plutons were emplaced concurrent with east-directed thrust faulting and localized primarily by northwest-trending strike-slip and related faults. The late-stage Butte Quartz Monzonite pluton was localized in a northeast-trending pull-apart structure that formed behind the active thrust front and is axially symmetric across the underlying northeast-striking Paleoproterozoic fault zone, interpreted as a crustal suture. The modeling of potential-field geophysical data indicates that pull-apart?stage magmas fed into the structure through two funnel-shaped zones beneath the batholith. Renewed magmatic activity in the southern feeder from 66 to 64 Ma led to the formation of two small porphyry-style copper-molybdenum deposits and ensuing world-class polymetallic copper- and silver-bearing veins in the Butte mining district. Vein orientations

  12. Measuring Officer Knowledge and Experience to Enable Tailored Training

    Science.gov (United States)

    2011-11-01

    activities like cartography or obstacle emplacement. To reduce demands on memory, the scale simply asked officers to check the boxes indicating whether or...10. Deployment History (Most recent first) Date: From Date: To Iraq Afghan Other Duty Position Unit Primary Mission e.g. Jun, 2007 Jul, 2008 X...Platoon Leader Route Clearance (Continue if more deployment experience) C-3 11. Assignment History

  13. New U-Pb zircon and 40Ar/39Ar muscovite age constraints on the emplacement of the Lizio syn-tectonic granite (Armorican Massif, France)

    OpenAIRE

    Tartese, Romain; Poujol, Marc; Ruffet, Gilles; Boulvais, Philippe; Yamato, Philippe; Kosler, Jan

    2011-01-01

    International audience; LA-ICP-MS U-Pb analyses performed on zircon grains from the Lizio granite yielded an emplacement age of 316 6 Ma. Typical S-C structures show that the Lizio granite was emplaced contemporaneously with dextral shearing along the northern branch of the South Armorican Shear Zone and that it was therefore active at that time. 40Ar/39Ar analyses performed on muscovite grains yielded plateau dates ranging between 311.5 and 308.2 Ma. Muscovite chemistry is typical of primary...

  14. Nanomedicine Faces Barriers

    Directory of Open Access Journals (Sweden)

    Paul Debbage

    2010-10-01

    Full Text Available Targeted nanoparticles have the potential to improve drug delivery efficiencies by more than two orders of magnitude, from the ~ 0.1% which is common today. Most pharmacologically agents on the market today are small drug molecules, which diffuse across the body’s blood-tissue barriers and distribute not only into the lesion, but into almost all organs. Drug actions in the non-lesion organs are an inescapable part of the drug delivery principle, causing “side-effects” which limit the maximally tolerable doses and result in inadequate therapy of many lesions. Nanoparticles only cross barriers by design, so side-effects are not built into their mode of operation. Delivery rates of almost 90% have been reported. This review examines the significance of these statements and checks how far they need qualification. What type of targeting is required? Is a single targeting sufficient? What new types of clinical challenge, such as immunogenicity, might attend the use of targeted nanoparticles?

  15. Higgs vacua behind barriers

    CERN Document Server

    Tamarit, Carlos

    2014-01-01

    Scenarios in which the Higgs vacuum arises radiatively and separated from the origin by a potential barrier at zero temperature are known to be attainable in models with extra singlet scalars, which in the limit of zero barrier height give rise to Coleman-Weinberg realizations of electroweak symmetry breaking. However, this requires large values of Higgs-portal couplings or a large number N of singlets. This is quantified in detail by considering, for varying N, the full two-loop effective potential at zero temperature, as well as finite temperature effects including the dominant two-loop corrections due to the singlets. Despite the large couplings, two-loop effects near the electroweak scale are under control, and actually better behaved in models with larger couplings yet fewer singlets. Strong first-order phase transitions are guaranteed even in the Coleman-Weinberg scenarios. Cubic Higgs couplings and Higgs associated-production cross sections exhibit deviations from the Standard Model predictions which c...

  16. Synthetic Eelgrass Oil Barrier

    Science.gov (United States)

    Curtis, T. G.

    2013-05-01

    Although surviving in situ micro-organisms eventually consume spilled oil, extensive inundation of shore biota by oil requires cleanup to enable ecological recovery within normal time scales. Although effective in calm seas and quiet waters, oil is advected over and under conventional curtain oil booms by wave actions and currents when seas are running. Most sorbent booms are not reusable, and are usually disposed of in landfills, creating excessive waste. A new concept is proposed for a floating oil barrier, to be positioned off vulnerable coasts, to interdict, contain, and sequester spilled oil, which can then be recovered and the barrier reused. While conventional oil boom designs rely principally on the immiscibility of oil in water and its relative buoyancy, the new concept barrier avoids the pitfalls of the former by taking advantage of the synergistic benefits of numerous fluid and material properties, including: density, buoyancy, elasticity, polarity, and surface area to volume ratio. Modeled after Zostera marina, commonly called eelgrass, the new barrier, referred to as synthetic eelgrass (SE), behaves analogously. Eelgrass has very long narrow, ribbon-like, leaves which support periphyton, a complex matrix of algae and heterotrophic microbes, which position themselves there to extract nutrients from the seawater flowing past them. In an analogous fashion, oil on, or in, seawater, which comes in contact with SE, is adsorbed on the surface and sequestered there. Secured to the bottom, in shoal waters, SE rises to the surface, and, if the tide is low enough, floats on the sea surface down wind, or down current to snare floating oil. The leaves of SE, called filaments, consist of intrinsically buoyant strips of ethylene methyl acrylate, aka EMA. EMA, made of long chain, saturated, hydrocarbon molecules with nearly homogeneous electron charge distributions, is a non-polar material which is oleophilic and hydrophobic. Oil must be in close proximity to the

  17. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius;

    2008-01-01

    Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation...... cementation is derived from internal sources. Rather, in spite of large variation in porosity and quartz cement content, a regular pattern of porosity decrease is related to increasing temperature or depth. The observed heterogeneity is due to local factors that influence the precipitation of quartz cement......, including sandstone architecture, i.e., distribution of shales within the sandstone bodies, and sandstone thickness. Heterogeneity is inherent to sandstone architecture and to the fact that silica for quartz cementation is derived from heterogeneously distributed local pressure solution. Models predicting...

  18. Understanding barriers to glycaemic control from the patient's perspective

    Directory of Open Access Journals (Sweden)

    Janes R

    2013-06-01

    Full Text Available INTRODUCTION: To better understand barriers to glycaemic control from the patient's perspective. METHODS: An interpretative phenomenological approach was used to study the experiences of 15 adults with Type 2 diabetes. Participants each gave a semi-structured interview of their experiences of living with diabetes. Interviews were transcribed, and themes extracted and organised using a patientcentred framework. FINDINGS: Participants' stories confirmed many of the barriers in the literature, particularly those related to context, such as family, finances, work. Barriers also related to negative emotional reactions to diabetes: fear of new events (diagnosis, starting pills/insulin; guilt about getting diabetes and not controlling it; and shame about having diabetes. Barriers also related to unscientific beliefs and personal beliefs. There were additional barriers related to poor clinician-patient relationships. Overall, participants had a poor understanding of diabetes, and complained that their clinician simply 'told them what to do'. CONCLUSION: Using a patient-centred approach, this study identified many barriers to glycaemic control. We suggest that a key barrier is clinician ignorance of their patients' fears, beliefs, expectations, context; of what constitutes a positive therapeutic relationship; and of the limitations of a biomedical approach to patient non-adherence. Faced with both a worsening diabetes epidemic and increasing health care workforce shortages, clinicians urgently need to understand that it is they, not their patients, who must change their approach if diabetes care is to be improved.

  19. Seismic imaging reveals crust and upper mantle morphology of seamounts: Understanding the emplacement and evolution of the Louisville Ridge

    Science.gov (United States)

    Robinson, A. H.

    2015-12-01

    Geophysical studies of submarine magmatic features have identified diversity in their crustal and upper mantle structure resulting in two end-members: the first showing magmatic underplating of high density material at the pre-existing Moho; the second characterised by less dense material being vertically intruded to shallow depths. The age of the underlying seafloor at the time of emplacement is thought to control the internal structure, as the vulnerability of the crust to magmatism may depend on thickness and temperature. The Louisville Ridge Seamount Chain (LRSC) intersects the Tonga-Kermadec subduction zone at ~26˚S. At this point the LRSC is located proximal to an extinct oceanic spreading center, with the underlying seafloor suggested to be ~10 Ma older than the seamounts.Multichannel seismic (MCS) reflection and wide-angle (WA) refraction data were acquired along a series of profiles over the LRSC. The bathymetry makes seismic phase identification challenging due to a high degree of lateral variability and scattering. A forward ray-tracing approach, permitting testing of phase identifications, is applied to the refracted first arrivals to develop a crustal and upper mantle velocity model. Constraint on the positioning of upper crustal layers is provided by comparison of model boundaries with reflectors in the MCS data, and identification and modeling of secondary phases, e.g. Moho reflections.We present velocity models used to establish the nature of the crustal and sub-crustal dynamic support of the LRSC, and whether it displays any along-ridge variation. Profiles acquired perpendicular to the LRSC enable us to investigate the three-dimensionality of structures. In particular, we seek to determine whether the seamount interior structure and 3-D geometry of the crust-mantle interface provide any insight into the controls on the emplacement of the LRSC, and how this fits within the range that has been suggested by studies at other seamount chains.

  20. Barriers for recess physical activity

    DEFF Research Database (Denmark)

    Pawlowski, Charlotte Skau; Tjørnhøj-Thomsen, Tine; Schipperijn, Jasper

    2014-01-01

    BACKGROUND: Many children, in particular girls, do not reach the recommended amount of daily physical activity. School recess provides an opportunity for both boys and girls to be physically active, but barriers to recess physical activity are not well understood. This study explores gender...... differences in children's perceptions of barriers to recess physical activity. Based on the socio-ecological model four types of environmental barriers were distinguished: natural, social, physical and organizational environment. METHODS: Data were collected through 17 focus groups (at 17 different schools...... this study, we recommend promoting recess physical activity through a combination of actions, addressing barriers within the natural, social, physical and organizational environment....

  1. Summary report on close-coupled subsurface barrier technology: Initial field trials to full-scale demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, J.H. [Brookhaven National Lab., Upton, NY (United States). Environmental and Waste Technology Center; Dwyer, B. [Sandia National Lab., Albuquerque, NM (United States)

    1997-09-01

    The primary objective of this project was to develop and demonstrate the installation and measure the performance of a close-coupled barrier for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional, low-cost, cement-grout containment barrier followed by a thin lining of a polymer grout. The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. The technology has matured from a regulatory investigation of the issues concerning the use of polymers to laboratory compatibility and performance measurements of various polymer systems to a pilot-scale, single column injection at Sandia to full-scale demonstration. The feasibility of the close-coupled barrier concept was proven in a full-scale cold demonstration at Hanford, Washington and then moved to the final stage with a full-scale demonstration at an actual remediation site at Brookhaven National Laboratory (BNL). At the Hanford demonstration the composite barrier was emplaced around and beneath a 20,000 liter tank. The secondary cement layer was constructed using conventional jet grouting techniques. Drilling was completed at a 45{degree} angle to the ground, forming a cone-shaped barrier. The primary barrier was placed by panel jet-grouting with a dual-wall drill stem using a two part polymer grout. The polymer chosen was a high molecular weight acrylic. At the BNL demonstration a V-trough barrier was installed using a conventional cement grout for the secondary layer and an acrylic-gel polymer for the primary layer. Construction techniques were identical to the Hanford installation. This report summarizes the technology development from pilot- to full-scale demonstrations and presents some of the performance and quality achievements attained.

  2. Combined acoustical and visual performance of noise barriers in mitigating the environmental impact of motorways.

    Science.gov (United States)

    Jiang, Like; Kang, Jian

    2016-02-01

    This study investigated the overall performance of noise barriers in mitigating environmental impact of motorways, taking into consideration their effects on reducing noise and visual intrusions of moving traffic, but also potentially inducing visual impact themselves. A laboratory experiment was carried out, using computer-visualised video scenes and motorway traffic noise recordings to present experimental scenarios covering two traffic levels, two distances of receiver to road, two types of background landscape, and five barrier conditions including motorway only, motorway with tree belt, motorways with 3 m timber barrier, 5m timber barrier, and 5m transparent barrier. Responses from 30 participants of university students were gathered and perceived barrier performance analysed. The results show that noise barriers were always beneficial in mitigating environmental impact of motorways, or made no significant changes in environmental quality when the impact of motorways was low. Overall, barriers only offered similar mitigation effect as compared to tree belt, but showed some potential to be more advantageous when traffic level went high. 5m timber barrier tended to perform better than the 3m one at the distance of 300 m but not at 100 m possibly due to its negative visual effect when getting closer. The transparent barrier did not perform much differently from the timber barriers but tended to be the least effective in most scenarios. Some low positive correlations were found between aesthetic preference for barriers and environmental impact reduction by the barriers.

  3. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    and intercultural communication, this article analyses interviews with 31 employees from two highly ethnically diverse Danish workplaces. The article shows how linguistic barriers such as different levels of majority language competence and their consequent misunderstandings breed mistrust and hostility, whilst......The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... groups, the sociology of work needs to develop a better understanding of the way in which linguistic diversity influences the formation of social capital, i.e. resources such as the trust and reciprocity inherent in social relations in such workplaces. Drawing on theories about intergroup contact...

  4. Countermeasures and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Johannes [Oersted - DTU, Automation, Kgs. Lyngby (Denmark)

    2005-10-01

    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)

  5. Evolution of diamond resorption in a silicic aqueous fluid at 1-3 GPa: Application to kimberlite emplacement and mantle metasomatism

    Science.gov (United States)

    Zhang, Zhihai; Fedortchouk, Yana; Hanley, Jacob J.

    2015-06-01

    Natural diamonds grow and partially dissolve during mantle metasomatism and undergo further resorption during the ascent to the Earth's surface in kimberlite magmas. This study uses atomic force microscopy (AFM) for quantitative characterization of diamond resorption morphology in order to provide robust constraints of the composition of kimberlitic and mantle metasomatic fluids. We performed experiments in a piston-cylinder apparatus at pressures (P) of 1-3 GPa and temperatures (T) of 1150-1400 °C to examine the impact of P, T, and silica content of an aqueous fluid on diamond dissolution. Petrographic observation and microthermometry of synthetic fluid inclusions trapped in olivine at the run conditions provide constraints on the composition and density of the fluid reacting with the diamond. Our results confirm an inverse relationship between P and T on diamond dissolution kinetics. A P increase of 1 GPa suppresses diamond oxidation rates by the same value as a T decrease by 50 °C, while the transformation rate of diamond crystal morphology from octahedron to tetrahexahedron increases with both P and T. All dissolved diamonds develop glossy surfaces, ditrigonal {111} faces, sheaf striations, and negative trigons, while circular pits only occur in aqueous fluids with low silica content (≤ 4.2 mol/kg) at 1 GPa. We identify five distinct morphological groups of trigons: two types of point-bottomed (p/b) (trumpet- and V-shaped) and three types of flat-bottomed (f/b) (trumpet-shaped, trapezoid-shaped and rounded). AFM measurements of trigons from two successive runs showed three stages of their evolution. Etch pits nucleate at defects as trumpet p/b trigons with the vertical dissolution rate (Vd) faster than the dissolution rates at the surface free of defects; they further develop by growth of the bottoms in (111) plane to create trumpet-shaped f/b trigons accompanied by decrease in Vd; and finally form trapezoid-shaped f/b trigon with constant wall angles. The

  6. The role of viscosity in the emplacement of high-temperature acidic flows of Serra Geral Formation in Torres Syncline (Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Matheus Silva Simões

    Full Text Available The acidic flows from Serra Geral Formation in Torres Syncline, Rio Grande do Sul, Brazil, are on the top of a volcanic sequence composed by a complex facies association of compound, simple and rubbly pahoehoebasic flows, acidic lava domes, and tabular acidic lava flows. The origin and emplacement conditions of the acidic volcanic rocks are discussed in this paper based on petrology, on calculated apatite saturation thermometry temperatures, and on estimated viscosity data. The liquidus temperatures for metaluminous rhyodacite to rhyolite samples are about 1,067.5 ± 25ºC in average. The viscosity (η values vary from 105 to 106 Pas for anhydrous conditions, suggesting the emplacement of high-temperature - low-viscosity lava flows and domes. The occurrence of acidic lava domes above simple pahoehoe flows as flow-banded vitrophyres was under low effusion rates, in spite of their high temperature and low viscosities, which are reflected in their small height. The emplacement of lava domes has continued until the eruption of rubbly pahoehoe flows and the geometry of these deposits rugged the relief. Presence of tabular acidic lava flows covering the landscape indicates that it was under high effusion rates conditions and such flows had well-insulated cooled surface crusts. The capacity to attain greater distances and overpass relief obstacles is explained not only by high effusion rates, but also by very low viscosities at the time of emplacement.

  7. A brief comparison of lava flows from the Deccan Volcanic Province and the Columbia-Oregon Plateau Flood Basalts: Implications for models of flood basalt emplacement

    Indian Academy of Sciences (India)

    Ninad Bondre; Raymond A Duraiswami; Gauri Dole

    2004-12-01

    The nature and style of emplacement of Continental Flood Basalt (CFB) lava flows has been a atter of great interest as well as considerable controversy in the recent past. However, even a cursory review of published literature reveals that the Columbia River Basalt Group (CRBG) and Hawaiian volcanoes provide most of the data relevant to this topic. It is interesting to note, however, that the CRBG lava flows and their palaeotopographic control is atypical of other CFB provinces in the world. In this paper, we first present a short overview of important studies pertaining to the emplacement of flood basalt flows. We then briefly review the morphology of lava flows from the Deccan Volcanic Province (DVP) and the Columbia-Oregon Plateau flood basalts. The review underscores the existence of significant variations in lava flow morphology between different provinces, and even within the same province. It is quite likely that there were more than one way of emplacing the voluminous and extensive CFB lava flows. We argue that the establishment of general models of emplacement must be based on a comprehensive documentation of lava flow morphology from all CFB provinces.

  8. Barriers to adherence in adolescents and young adults with cystic fibrosis

    DEFF Research Database (Denmark)

    Bregnballe, Vibeke; Schiøtz, Peter Oluf; Boisen, Kirsten A;

    2011-01-01

    Treatment adherence is crucial in patients with cystic fibrosis, but poor adherence is a problem, especially during adolescence. Identification of barriers to treatment adherence and a better understanding of how context shapes barriers is of great importance in the disease. Adolescent reports of...... of barriers to adherence have been studied, but studies of their parents' experience of such barriers have not yet been carried out. The aim of the present study was to explore barriers to treatment adherence identified by young patients with cystic fibrosis and by their parents....

  9. Barriers to Women in Science

    Science.gov (United States)

    Butler, Rosemary

    2013-01-01

    The Presiding Officer of the National Assembly for Wales, Rosemary Butler AM, has put the issue of barriers to women in public life at the top of the political agenda in Wales. She has held sessions with women across Wales to find out what those barriers are and how they can be tackled. On International Women's Day in February, she invited…

  10. Spanning trees crossing few barriers

    NARCIS (Netherlands)

    Asano, T.; Berg, M. de; Cheong, O.; Guibas, L.J.; Snoeyink, J.; Tamaki, H.

    2002-01-01

    We consider the problem of finding low-cost spanning trees for sets of n points in the plane, where the cost of a spanning tree is defined as the total number of intersections of tree edges with a given set of m barriers. We obtain the following results: (i) if the barriers are possibly intersecting

  11. BARRIERS OF STRATEGIC ALLIANCES ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Vladislav M. Sannikov

    2014-01-01

    Full Text Available General barriers of organization of different types of strategic alliances have beenconsidered in the article. There are several recommendations for overcoming themin cases of international alliances, and in case of work in one state. The article also identified goals and tasks of single coordination center of alliance to overcome organization barriers.

  12. Informal export barriers and poverty

    OpenAIRE

    Porto, Guido G.

    2004-01-01

    The author investigates the poverty impacts of informal export barriers like transport costs, cumbersome customs practices, costly regulations, and bribes. He models these informal barriers as export taxes that distort the efficient allocation of resources. In low-income agricultural economies, this distortion lowers wages and household agricultural income, thereby leading to higher pover...

  13. Nature and time of emplacement of a pegmatoidal granite within the Delhi Fold Belt near Bayalan, Rajasthan, India

    Science.gov (United States)

    Dasgupta, N.; Sen, J.; Pal, T.; Ghosh, T.

    2009-04-01

    The study area is situated about 70 km south east of Ajmer, in Rajasthan, India around the village Bayala (26o 02' 19 N''; 74o 21' 01'') within the Ajmer district of Central Rajasthan. The area is along the eastern flank of the central portion of the Precambrian South Delhi Fold Belt (SDFB) and it stratigraphically belongs to the Bhim Group of rocks. Basement rocks of Archaean age, commonly known as the Banded gneissic Complex (BGC), is exposed to the east, where the rocks of the Bhim Group rests unconformably over BGC. To the west gneissic basement rocks of mid-Proterozoic times underlie the Bhim Group and have been referred to as the Beawar gneiss (BG). The Bhim Group of rocks comprises of metamorphosed marls and calc-silicate gneisses with minor amounts of quartzites and pelitic schists, indicative of its shallow marine origin. Within the Bhim Group, a pegmatoidal granite has intruded the calc silicate gneisses of the area. The pegmatoidal granite body is elliptical in outline with the long dimension(20 km) trending N-S and covers an area of 300 sq. km. approximately. This granite have so far been mapped as basement rocks (BG) surrounding the Beawar town (26o 06' 05'' N; 74o 19' 03'' E), 50 km south east of Ajmer. Rafts of calc-silicate gneisses, belonging to the Bhim Group, are seen to be entrapped within granite. Fragments of BG and its equivalents have also been found as caught up blocks within this pegmatoidal granite body near Andheri Devari, a small hamlet east of Beawar. The objective of the study was to map this pegmatoidal body, and decipher the mechanism and time of emplacement of this granite. A detailed structural mapping of the area in a 1:20000 scale spread over a 30 sq. km area in the vicinity of Bayala was carried out to analyse the geometry and the time of emplacement of the pegmatitic granite. The ridges of calc silicates and marbles adjoining the area were studied for the structural analyses of the Delhi fold belt rocks of the area. The calc

  14. Automated Impedance Tomography for Monitoring Permeable Reactive Barrier Health

    Energy Technology Data Exchange (ETDEWEB)

    LaBrecque, D J; Adkins, P L

    2009-07-02

    The objective of this research was the development of an autonomous, automated electrical geophysical monitoring system which allows for near real-time assessment of Permeable Reactive Barrier (PRB) health and aging and which provides this assessment through a web-based interface to site operators, owners and regulatory agencies. Field studies were performed at four existing PRB sites; (1) a uranium tailing site near Monticello, Utah, (2) the DOE complex at Kansas City, Missouri, (3) the Denver Federal Center in Denver, Colorado and (4) the Asarco Smelter site in East Helena, Montana. Preliminary surface data over the PRB sites were collected (in December, 2005). After the initial round of data collection, the plan was modified to include studies inside the barriers in order to better understand barrier aging processes. In September 2006 an autonomous data collection system was designed and installed at the EPA PRB and the electrode setups in the barrier were revised and three new vertical electrode arrays were placed in dedicated boreholes which were in direct contact with the PRB material. Final data were collected at the Kansas City, Denver and Monticello, Utah PRB sites in the fall of 2007. At the Asarco Smelter site in East Helena, Montana, nearly continuous data was collected by the autonomous monitoring system from June 2006 to November 2007. This data provided us with a picture of the evolution of the barrier, enabling us to examine barrier changes more precisely and determine whether these changes are due to installation issues or are normal barrier aging. Two rounds of laboratory experiments were carried out during the project. We conducted column experiments to investigate the effect of mineralogy on the electrical signatures resulting from iron corrosion and mineral precipitation in zero valent iron (ZVI) columns. In the second round of laboratory experiments we observed the electrical response from simulation of actual field PRBs at two sites: the

  15. Epistemological barriers to radical behaviorism.

    Science.gov (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  16. Epistemological barriers to radical behaviorism

    Science.gov (United States)

    O'Donohue, William T.; Callaghan, Glenn M.; Ruckstuhl, L. E.

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers. PMID:22478314

  17. Engineered Barrier Systems Thermal-Hydraulic-Chemical Column Test Report

    Energy Technology Data Exchange (ETDEWEB)

    W.E. Lowry

    2001-12-13

    The Engineered Barrier System (EBS) Thermal-Hydraulic-Chemical (THC) Column Tests provide data needed for model validation. The EBS Degradation, Flow, and Transport Process Modeling Report (PMR) will be based on supporting models for in-drift THC coupled processes, and the in-drift physical and chemical environment. These models describe the complex chemical interaction of EBS materials, including granular materials, with the thermal and hydrologic conditions that will be present in the repository emplacement drifts. Of particular interest are the coupled processes that result in mineral and salt dissolution/precipitation in the EBS environment. Test data are needed for thermal, hydrologic, and geochemical model validation and to support selection of introduced materials (CRWMS M&O 1999c). These column tests evaluated granular crushed tuff as potential invert ballast or backfill material, under accelerated thermal and hydrologic environments. The objectives of the THC column testing are to: (1) Characterize THC coupled processes that could affect performance of EBS components, particularly the magnitude of permeability reduction (increases or decreases), the nature of minerals produced, and chemical fractionation (i.e., concentrative separation of salts and minerals due to boiling-point elevation). (2) Generate data for validating THC predictive models that will support the EBS Degradation, Flow, and Transport PMR, Rev. 01.

  18. Emplacement and Solidification of Inter-Layerd Silicic and Mafic Magmas, Isle au Haut Igneous Complex, Maine

    Science.gov (United States)

    Patwardhan, K.; Marsh, B. D.

    2006-05-01

    The Isle au Haut Igneous Complex, Maine, presents an intriguing association of basaltic and granitic rocks in the form of a composite layered sequence of alternating gabbroic and dioritic units. The 413 Ma complex may have formed by periodic replenishment or invasion of mafic magma into an evolving, more silicic magma chamber (Chapman & Rhodes, 1992; JVGR). The interaction of a denser magma overlying a less dense magma promotes Rayleigh-Taylor instabilities (RTI), resulting in overturning initiated through pipes and the eventual formation of a stable configuration of diorite over gabbro (Chapman & Rhodes, 1992; JVGR). Field exposures on the southern parts of the island covering a 160 m section through the sequence shows four gabbroic-dioritic pairs (i.e., gabbro over diorite) exhibiting strong interaction between the two in the forms of diapiric pipes of diorite intruding gabbro and gabbro pillows caught in diorite. It is clear that the two magmas were simultaneously molten, and this presents an opportunity to observe the physics and chemistry of interaction between gabbroic magma and partly molten diorite. Emplacement of denser, sill like gabbroic magma over solidifying, less dense dioritic magma may also have given rise to structures resembling load casts and flame structures common to sedimentary rocks. That the diorite was significantly solidified (e.g., ~55% crystals) at the time of intrusion of the gabbroic magma is reflected in field and textural relationships suggesting that overturning due to gravitational instability was initiated but did not go to completion. That is, the diorite was strong enough to act as a rigid medium for gabbro emplacement and subsequent support without wholesale mixing, but at the same time was weak enough to yield low density melt, perhaps through compaction, to undergo RTI at the interfaces and form extensive ensembles of diapiric pipes in the overlying gabbro. We examine the physics and chemistry of this process beginning with

  19. The Origin and Emplacement Patterns of Paleoproterozoic (2.5-1.8 Ga) Mafic/Ultramafic Magmatism

    Science.gov (United States)

    Heaman, L. M.

    2010-12-01

    The Paleoproterozoic (~2.5-1.8 Ga) is a stunning period in Earth history where numerous giant dyke swarms were emplaced and can be found transecting Archean cratons worldwide, the onset of this magmatism follows closely the ~2.6 Ga stabilization of most Archean cratons. Based on conservative estimates, the volumes of basaltic magma produced in the Paleoproterozoic rival more contemporary LIPs (>1M km3). Often, only the root zones of Paleoproterozoic LIPs are preserved (mafic/ultramafic dyke swarms and layered mafic intrusions) so the complete erosion of the volcanic succession in many examples, the repeated emplacement of dyke swarms into zones of crustal weakness over protracted periods of time (e.g. >400 m.y.), and the fact that some Proterozoic LIPs are metamorphosed adds to the difficulty in deciphering their origin. Equally challenging is determining whether this period of voluminous outpouring of mafic magma could be the cause of several unique features of Earth evolution at this time; for example, triggering extreme climate conditions, initiating the abrupt increase in the oxygen content of the atmosphere, promoting the rapid production of banded iron formations, causing isobaric high-grade metamorphism and granite production in the lower crust, and contributing to substantial downward continental root growth through underplating of basaltic magma. Based on a compilation of more than 200 precise and accurate U-Pb dates for Paleoproterozoic mafic/ultramafic dykes, sills and layered mafic intrusions, at least three synchronous global events (~2.50, 2.23, and 1.88 Ga) and two active mantle-derived magmatic cycles can be identified in the period 2.5-1.8 Ga (2520-2370 and 2230-1820 Ma), with a distinct hiatus between 2370 and 2230 Ma. The beginning of each magmatic cycle is represented by the widespread emplacement of dyke swarms on several cratons within a relatively short time interval of ~20 m.y. In the Superior Province, Canada the onset of 2.52-2.50 Ga mafic

  20. Characteristics and hydrodynamic interpretation of storm-emplaced cliff-top boulder ridges on Inishmore, Aran Islands, Ireland

    Science.gov (United States)

    Zentner, D. B.; Cox, R.

    2008-12-01

    Dramatic boulder ridges are widespread on cliff-top platforms of Ireland's Aran Islands, emplaced by storm waves at elevations up to 50 m. In places the ridges have overridden 19th-century field walls, and recent movement of large blocks is attested to by modern debris--including nylon ropes, aerosol cans, and plastic bottles--pinned under megaclasts of up to 40 tons. Large waves are common off Ireland's west coast, as revealed by the short records available from recently-deployed buoy systems. The Irish Marine Weather Buoy Network measured wave heights (≥10 m on 29 days between 2001 and 2007, and waves up to 18 m high were recorded in December 2007. Blocks quarried by such waves from the upper few m of the cliffs are transported inland to form semi-continuous boulder ridges parallel to the coastline, which therefore offer a record of hydrodynamics during high-energy wave events. On Inishmore, boulder ridges occur at elevations up to 28 m, separated from the cliff edge by wave-scoured platforms 1-70 m wide. The ridges consist of imbricated, highly angular slabs, ranging from small gravel to 5 m megaclasts. They are 1-4.6 m high, 10-48 m wide (Ripple Index 5-17), and strongly asymmetric, with steep narrow stoss faces (10- 35°), and long gentle lee slopes (<14°). With increasing cliff height, ridges are smaller, narrower, made of smaller blocks, and sit closer to the edge; but ridges 20 m wide and 2 m high, with half-ton clasts, occur as high as 28 m OD. The deposits are moderately to well sorted, predominantly unimodal, and fine skewed. Median clast size ranges from fine to coarse boulders (0.5-2 m). Clasts show strong seaward imbrication on both stoss and lee sides (dipping up to 85° with average 25°). "Blowout" features on the lee sides, with boulders imbricated radially around central depressions of 1-2 m diameter, suggest turbulent flow separation, as does the common occurrence of 1-3 smaller secondary ridges landward of the main crest. The uniformity of

  1. Development and testing of the pneumatic lunar drill for the emplacement of the corner cube reflector on the Moon

    Science.gov (United States)

    Zacny, K.; Currie, D.; Paulsen, G.; Szwarc, T.; Chu, P.

    2012-10-01

    Lunar Laser Ranging provides a highly accurate measurement of the distance between ground stations on Earth and reflectors on the surface of the Moon. Since retroreflectors were initially placed during the Apollo missions, the ground stations improved the ranging accuracy by a factor of 200 and now the Apollo-era arrays on the Moon pose a significant limitation to the ranging accuracy. The new Lunar Laser Ranging Retroreflector (i.e. the Lunar Laser Ranging retroreflector for the 21st century or LLRRA-21) would provide extensive new information on the lunar interior, general relativity, and cosmology. During the day/night lunar cycle, when the thermal variation of the surface is approximately 300 °C, the regolith will rise and fall by almost 500 μm. Yet, it is estimated that the thermal variation 0.5 m to 1 m below the surface is less than much 1 °C. Thus for the lunar emplacement to support 10s of microns ranging accuracy, the reflectors must be anchored to that thermally stable mass at 0.5 m or greater depth. In this paper, we present a novel method of deploying LLRRA-21 with a Corner Cube Reflector (CCR) on the Moon. The emplacement approach uses a gas-powered drill consisting of a >50 cm long, slim, hollow rod with a perforated anchor-cone at its lower end and the CCR mounted to the top. Gas supplied from a small tank is directed into and down the rod and out through the cone, lofting the soil out of the hole and allowing the rod to sink under its own weight to a depth of 0.5 m. To determine the system performance, we conducted several tests in compacted JSC-1a lunar soil simulant and inside a vacuum chamber. In several tests, the rod successfully sunk under its own weight of 16 N to a depth of 50 cm in 4-6 min. The pneumatic system is the game-changer for subsurface access. The extremely low mass and volume required to reach 50 cm, along with very simple penetration method allow the CCR to remain in a variety of payload architectures.

  2. Sill emplacement and corresponding ground deformation processes at the Alu-Dalafilla volcanic centre in the Danakil Depression, Ethiopia

    Science.gov (United States)

    Magee, Craig; Bastow, Ian; Hetherington, Rachel; van Wyk de Vries, Ben; Jackson, Christopher

    2016-04-01

    A consensus has emerged from a variety of disciplines over the past 15 years that Quaternary magmatism in Ethiopia is almost entirely dominated by dike intrusion. Focused dike intrusion within 60 km long, 20 km wide, rift zones is considered to mark the present day locus of extension in Ethiopia, and represent the proto-ridge axis location of an incipient ocean spreading centre. However, it has been suggested on the strength of Moho depths and Quaternary eruptive volumes in northernmost Ethiopia, that the final transition from continental rifting to incipient oceanic spreading may instead be characterised by an abrupt, rheologically driven, late-phase of crustal thinning. Development of a sedimentary basin and mantle decompression melting occurring in the Danakil Depression, driven by this late-phase crustal thinning, should result in a markedly different style of magmatism in the upper crust: i.e. field observations, high-resolution seismic reflection studies, and experimental modelling suggest that interconnected networks of sill intrusions dominate in sedimentary basins. Here, we present the first evidence from the Danakil Depression that links surficial structures, observed at the Alu-Dalafilla volcanic centre, to the ongoing emplacement of an underlying sill. In particular, we use satellite imagery to examine a dome-shaped fold, associated fracture patterns, and surrounding lava flows, which we suggest likely formed in response to roof uplift above and extrusion from a saucer-shaped sill; i.e. a sub-horizontal inner sill encircled by an inward-dipping, transgressive inclined rim. InSAR observations by Pagli et al. (2012) of ground uplift and deflation occurring during the eruption of basaltic lava at Alu-Dalafilla in 2008 capture what we believe to be the first real-time evidence for intrusion-induced forced folding dynamics above a saucer-shaped sill. InSAR data further suggest that intrusion occurred at a depth of ~1 km, likely placing the sill within an

  3. Diamond resorption features as a new method for examining conditions of kimberlite emplacement

    Science.gov (United States)

    Fedortchouk, Yana

    2015-10-01

    The study develops a new approach utilizing parameters of trigonal etch pits on diamond crystals to infer the conditions of diamond residence in kimberlite magma. Diamond crystals from dissolution experiments conducted at 1 GPa and 1150-1350 °C in the presence of H2O-rich or CO2-rich fluid were studied with atomic force microscopy (AFM). The AFM data of resorbed diamond surfaces show that much deeper surface relief was produced in CO2 fluid. It also clearly distinguishes the profiles of the trigonal etch pits forming regular flat-bottomed trigons in H2O fluid, and round- or pointed-bottomed trigons in CO2 fluid. The relationship between the diameter and the depth of the trigonal pits is found to be another important indicator of the fluid composition. Dissolution in H2O fluid develops trigons with constant diameter and variable depth where the diameter increases with temperature. Trigons developed in CO2 fluid have a large range of diameters showing a strong positive correlation with the depth. The developed criteria applied to the natural diamond crystals from three Ekati Mine kimberlites indicate significant variation in CO2-H2O ratio and temperature of their magmatic fluid. This conclusion based on diamond resorption agrees with the mineralogy of microphenocrysts and groundmass of the studied kimberlites offering new method to study crystallization conditions of kimberlite magma.

  4. The "Battle" of Managing Language Barriers in Health Care.

    Science.gov (United States)

    Steinberg, Emma M; Valenzuela-Araujo, Doris; Zickafoose, Joseph S; Kieffer, Edith; DeCamp, Lisa Ross

    2016-02-18

    Providing safe and high-quality health care for children whose parents have limited English proficiency (LEP) remains challenging. Reports of parent perspectives on navigating language discordance in health care are limited. We analyzed portions of 48 interviews focused on language barriers from 2 qualitative interview studies of the pediatric health care experiences of LEP Latina mothers in 2 urban US cities. We found mothers experienced frustration with health care and reported suboptimal accommodation for language barriers. Six themes emerged relevant to health care across settings: the "battle" of managing language barriers, preference for bilingual providers, negative bias toward interpreted encounters, "getting by" with limited language skills, fear of being a burden, and stigma and discrimination experienced by LEP families. Parents' insights highlight reasons why effective language accommodation in health care remains challenging. Partnering with families to address the management of language barriers is needed to improve health care quality and safety for LEP patients and families.

  5. Geochemical barriers for environment protection and recovery of nonferrous metals.

    Science.gov (United States)

    Chanturiya, Valentine; Masloboev, Vladimir; Makarov, Dmitriy; Nesterov, Dmitriy; Bajurova, Julia; Svetlov, Anton; Men'shikov, Yuriy

    2014-01-01

    A study of natural minerals, ore tailings and their products as materials for artificial geochemical barriers is presented. In particular, it focuses on interaction between calcite and dolomite and sulfate solutions containing nickel, copper and iron under static conditions. Calcite of -0.1 mm fraction has been shown to perform well as a barrier when added to water phases of tailing dumps and natural reservoirs. Experiments under dynamic conditions have revealed a high potential of thermally activated copper-nickel tailings as barriers. After a 500-day precipitating period on a geochemical barrier, the contents of nickel and copper in ore dressing tailings were found to increase 12- and 28-fold, respectively. An effective sorbent of copper, iron and nickel ions is a brucite-based product of hydrochloric acid treatment of vermiculite ore tailings. Its sorption capacity can be essentially increased through thermal activation.

  6. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

    2016-01-01

    The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates......-through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous...

  7. A LOOK AT CULTURAL BARRIERS

    Directory of Open Access Journals (Sweden)

    Carmen A. VRÂNCEANU

    2015-06-01

    Full Text Available Nowadays the global market allows each individual to work in foreign countries. This fact is a great opportunity for business development, but also puts into light the problem of cultural barriers. Ineffective cross-cultural communication and collaboration can harm employees, customers, and other stakeholders. A company with employees from different cultures must acknowledge and understand these barriers in order to overcome them and to obtain the desired performance. The present study aims to expose the cultural barriers encountered by foreigners in a multinational company from Romania.

  8. Emplacement history and inflation evidence of a long basaltic lava flow located in Southern Payenia Volcanic Province, Argentina

    Science.gov (United States)

    Bernardi, Mauro I.; Bertotto, Gustavo W.; Jalowitzki, Tiago L. R.; Orihashi, Yuji; Ponce, Alexis D.

    2015-02-01

    The El Corcovo lava flow, from the Huanul shield volcano in the southern Mendoza province (central-western Argentina) traveled a distance of 70 km and covered a minimum area of ~ 415 km2. The flow emplacement was controlled both by extrinsic (e.g., topography) and intrinsic (e.g., lava supply rate, lava physicochemical characteristics) factors. The distal portion of the lava flow reached the Colorado River Valley, in La Pampa Province, where it spread and then was confined by earlier river channels. Cross-sections through the flow surveyed at several localities show two vesicular layers surrounding a dense central section, where vesicles are absent or clustered in sheet-shaped and cylindrical-shaped structures. Lavas of the El Corcovo flow are alkaline basalts with low values of viscosity. The morphological and structural characteristics of the flow and the presence of landforms associated with lava accumulation are the evidence of inflation. This process involved the formation of a tabular sheet flow up to 4 m of thick with a large areal extent in the proximal sectors, while at terminal sectors frontal lobes reached inflation values up to 10 m. The numerous swelling structures present at these portions of the flow suggest the movement of lava in lava tubes. We propose that this aspect and the low viscosity of the lava allowed the flow travel to a great distance on a gentle slope relief.

  9. Borehole geophysical monitoring of amendment emplacement and geochemical changes during vegetable oil biostimulation, Anoka County Riverfront Park, Fridley, Minnesota

    Science.gov (United States)

    Lane, Jr., John W.; Day-Lewis, Frederick D.; Johnson, Carole D.; Joesten, Peter K.; Kochiss, Christopher S.

    2007-01-01

    The U.S. Geological Survey (USGS) conducted a series of geophysical investigations to monitor a field-scale biostimulation pilot project at the Anoka County Riverfront Park (ACP), downgradient from the Naval Industrial Reserve Ordnance Plant, in Fridley, Minnesota. The pilot project was undertaken by the U.S. Naval Facilities Engineering Command, Southern Division, for the purpose of evaluating biostimulation using emulsified vegetable oil to treat ground water contaminated with chlorinated hydrocarbons. Vegetable oil was introduced to the subsurface to serve as substrate for naturally occurring microbes, which ultimately break down chlorinated hydrocarbons into chloride, carbon dioxide, and water through oxidation-reduction reactions. In support of this effort, the USGS collected cross-borehole radar data and conventional borehole geophysical data in five site visits over 1.5 years to evaluate the effectiveness of geophysical methods for monitoring emplacement of the vegetable oil emulsion and for tracking changes in water chemistry. Radar zero-offset profile (ZOP) data, radar traveltime tomograms, electromagnetic (EM) induction logs, natural gamma logs, neutron porosity logs, and magnetic susceptibility logs were collected and analyzed.

  10. Indicators for Assessing Climate Change Resilience Resulting from Emplacement of Green Infrastructure Projects Across an Urban Landscape

    Science.gov (United States)

    Parish, E. S.; Omitaomu, O.; Sylvester, L.; Nugent, P.

    2015-12-01

    Many U.S. cities are exploring the potential of using green infrastructure (e.g., porous pavements, green roofs, street planters) to reduce urban storm water runoff, which can be both be a nuisance and costly to treat. While tools exist to measure local runoff changes resulting from individual green infrastructure (GI) projects, most municipalities currently have no method of analyzing the collective impact of GI projects on urban stormwater systems under future rainfall scenarios and impervious surface distribution patterns. Using the mid-sized city of Knoxville, Tennessee as a case study, we propose a set of indicators that can be used to monitor and analyze the collective effects of GI emplacement on urban storm water runoff volumes as well as to quantify potential co-benefits of GI projects (e.g., urban heat island reduction, reduced stream scouring) under different climate projection ensembles and population growth scenarios. These indicators are intended to help the city prioritize GI projects as opportunities arise, as well as to track the effectiveness of GI implementation over time. We explore the aggregation of these indicators across different spatial scales (e.g., plot, neighborhood, watershed, city) in order to assess potential changes in climate change resilience resulting from the collective implementation of GI projects across an urban landscape.

  11. Small-scale experimental tests of tandem mirror machines with thermal barriers

    Energy Technology Data Exchange (ETDEWEB)

    Drake, R.P.

    1979-09-01

    A summary is given of current physical understanding of tandem mirrors with thermal barriers. Physicists who understand tandem mirrors can use this document as a preliminary guide to the physical issues and experimental problems involved. This report will focus upon the issues that can be tested experimentally, and on the areas needing experimental and theoretical inventions. The next section discusses the plasma potentials and plasma confinement which correspond to a tandem mirror with thermal barriers, assuming the barriers exist in steady-state. The creation of a barrier is discussed, i.e., the natural tendency of the barrier cell to fill with plasma must be countered by pumping ions out of the barrier. The design of a barrier-pumping experiment for TMX is described.

  12. Geophysical modeling of the impact of Central Atlantic Magmatic Province emplacement on sea-level changes at the Triassic-Jurassic boundary

    Science.gov (United States)

    Austermann, Jacqueline; Bachan, Aviv; Eyster, Athena

    2015-04-01

    Mass extinctions have been linked to the emplacement of Large Igneous Provinces (LIPs). While increasing precision in the dating of LIPs indicates that extinctions are often synchronous with LIP eruptions, the complete causal chain of events - including impacts on climate, ocean chemistry, and sea level - remains incompletely understood. Here we utilize a numerical modeling approach to examine one possible link in this chain: the capacity of LIP emplacement to drive sea-level changes. We focus on the Late Triassic and Early Jurassic, an interval encompassing the end-Triassic mass extinction and the emplacement of the Central Atlantic Magmatic Province (CAMP). Excursions in sea level are also well documented at this time and in many places indicate a rapid fall followed by a sea-level rise coincident with the extinction. To explore the impact of CAMP on sea-level changes we use a geophysical model of solid-Earth deformation together with a reconstructed paleotopography during the end-Triassic. We perturb the model in two steps, corresponding to two phases of LIP emplacement: (1) Uplift associated with the ascending plume that leads to the CAMP eruption; and (2) loading and flexure of the lithosphere associated with the emplaced magma. We model the former process with a mantle convection code to assess the tempo-spatial behavior of dynamic uplift for varying plume sizes. The latter process is modeled as a viscoelastic loading problem that allows us to isolate contributions from the initial elastic and subsequent viscous response. Both mechanisms are combined in a gravitationally self-consistent sea-level theory that accounts for loading effects associated with displaced water, as well as shoreline migration and perturbations in Earth rotation. We compare model outputs to geological data from a set of sites in which the direction, magnitude, and age of sea level changes have been estimated for the end-Triassic period. Our calculations place bounds on the magnitude and

  13. International Collaboration Activities on Engineered Barrier Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jove-Colon, Carlos F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-08-31

    The Used Fuel Disposition Campaign (UFDC) within the DOE Fuel Cycle Technologies (FCT) program has been engaging in international collaborations between repository R&D programs for high-level waste (HLW) disposal to leverage on gathered knowledge and laboratory/field data of near- and far-field processes from experiments at underground research laboratories (URL). Heater test experiments at URLs provide a unique opportunity to mimetically study the thermal effects of heat-generating nuclear waste in subsurface repository environments. Various configurations of these experiments have been carried out at various URLs according to the disposal design concepts of the hosting country repository program. The FEBEX (Full-scale Engineered Barrier Experiment in Crystalline Host Rock) project is a large-scale heater test experiment originated by the Spanish radioactive waste management agency (Empresa Nacional de Residuos Radiactivos S.A. – ENRESA) at the Grimsel Test Site (GTS) URL in Switzerland. The project was subsequently managed by CIEMAT. FEBEX-DP is a concerted effort of various international partners working on the evaluation of sensor data and characterization of samples obtained during the course of this field test and subsequent dismantling. The main purpose of these field-scale experiments is to evaluate feasibility for creation of an engineered barrier system (EBS) with a horizontal configuration according to the Spanish concept of deep geological disposal of high-level radioactive waste in crystalline rock. Another key aspect of this project is to improve the knowledge of coupled processes such as thermal-hydro-mechanical (THM) and thermal-hydro-chemical (THC) operating in the near-field environment. The focus of these is on model development and validation of predictions through model implementation in computational tools to simulate coupled THM and THC processes.

  14. Variable parallax barrier spacing in autostereoscopic displays

    Science.gov (United States)

    Yoon, Seon Kyu; Khym, Sungwon; Kim, Hyun-Woo; Kim, Sung-Kyu

    2016-07-01

    In general, multi-view autostereoscopic displays can only provide autostereoscopic images with little crosstalk at the optimum viewing distance (OVD) in the depth direction, limiting the mobility of viewers. Therefore, this paper proposes a method of increasing viewer mobility in the depth direction by varying the distance separating the parallax barrier and the display. Computer simulations and experiments were conducted to verify changes in the OVD resulting from the application of the proposed method. The results showed that the proposed method is effective at changing the OVD with respect to changes in the viewing distance. Therefore this method minimizes changes in the 3D image quality due to the viewer's depth location.

  15. Low Conductivity Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dong-Ming

    2005-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and requirements will be discussed. An experimental approach is established to monitor in real time the thermal conductivity of the coating systems subjected to high-heat-flux, steady-state and cyclic temperature gradients. Advanced low conductivity thermal barrier coatings have also been developed using a multi-component defect clustering approach, and shown to have improved thermal stability. The durability and erosion resistance of low conductivity thermal barrier coatings have been improved utilizing advanced coating architecture design, composition optimization, in conjunction with more sophisticated modeling and design tools.

  16. Coastal Structures and Barriers 2012

    Data.gov (United States)

    California Department of Resources — This dataset is a compilation of the UCSC Sand Retention Structures, MC Barriers, and USACE Coastal Structures. UCSC Sand Retention Structures originate from a...

  17. Guided tissue regeneration. Absorbable barriers.

    Science.gov (United States)

    Wang, H L; MacNeil, R L

    1998-07-01

    Over the past 15 years, techniques aimed at regeneration of lost periodontal tissue have become widely used and accepted in clinical practice. Among these techniques are those which use the principles of guided tissue regeneration (GTR), wherein barriers (i.e., membranes) are used to control cell and tissue repopulation of the periodontal wound. A variety of non-absorbable and absorbable barriers have been developed and used for this purpose, with a trend in recent years toward increased use of absorbable GTR materials. This article describes the evolution of absorbable barrier materials and overview materials available for clinical use today. In addition, advantages and disadvantages of these materials are discussed, as well as possible new developments in barrier-based GTR therapy.

  18. Nonlocal reflection by photonic barriers

    OpenAIRE

    Vetter, R. -M.; A. Haibel; Nimtz, G.

    2001-01-01

    The time behaviour of microwaves undergoing partial reflection by photonic barriers was measured in the time and in the frequency domain. It was observed that unlike the duration of partial reflection by dielectric layers, the measured reflection duration of barriers is independent of their length. The experimental results point to a nonlocal behaviour of evanescent modes at least over a distance of some ten wavelengths. Evanescent modes correspond to photonic tunnelling in quantum mechanics.

  19. Schooling Inequality and Language Barriers

    OpenAIRE

    Parker, Susan W.; Rubalcava, Luis; Teruel, Graciela

    2005-01-01

    This article estimates the impact of language barriers on school achievement and the potential ameliorating role of bilingual education. Using large household data sets from poor rural communities in Mexico, we find that parental language (failure to speak Spanish) represents an important barrier to the schooling of indigenous children. We provide an empirical test suggesting that this largely reflects parental human capital related to culture/language, rather than unobserved wealth effects. ...

  20. Economic alternatives for containment barriers

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J. [Geo-Con, Inc., Monroeville, PA (United States)

    1997-12-31

    Fixation, barriers, and containment of existing landfills and other disposal areas are often performed by insitu auger type soil mixing and jet grouting. Cement or other chemical reagents are mixed with soil to form both vertical and horizontal barriers. Immobilization of contaminants can be economically achieved by mixing soil and the contaminants with reagents that solidify or stabilize the contaminated area. Developed in Japan, and relatively new to the United States, the first large scale application was for a vertical barrier at the Jackson Lake Dam project in 1986. This technology has grown in both the civil and environmental field since. The paper describes current United States practice for Deep Soil Mixing (over 12 meters in depth), and Shallow Soil Mixing for vertical barriers and stabilization/solidification, and Jet Grouting for horizontal and vertical barriers. Creating very low permeability barriers at depth with minimal surface return often makes these techniques economical when compared to slurry trenches. The paper will discuss equipment, materials, soil and strength parameters, and quality control.

  1. THE INFLUENCE OF BARRIERS ON FLAME AND EXPLOSION WAVE IN GAS EXPLOSION

    Institute of Scientific and Technical Information of China (English)

    林柏泉; 周世宁; 张仁贵

    1998-01-01

    This paper researches into the influence of barriers on flame and explosion wave in gasexplosion on the basis of experiment. The result shows that the barrier is very important to thetransmission of flame and explosion wave in gas explosion. When there are barriers, the speed oftransmission would be very fast and shock wave will appear in gas explosion, which would in-crease gas explosion power. The result of research is very important to prevent gas explosion anddecrease the power of it.

  2. Site characterization plan conceptual design report for a high-level nuclear waste repository in salt, vertical emplacement mode: Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1987-12-01

    This Conceptual Design Report describes the conceptual design of a high-level nuclear waste repository in salt at a proposed site in Deaf Smith County, Texas. Waste receipt, processing, packing, and other surface facility operations are described. Operations in the shafts underground are described, including waste hoisting, transfer, and vertical emplacement. This report specifically addresses the vertical emplacement mode, the reference design for the repository. Waste retrieval capability is described. The report includes a description of the layout of the surface, shafts, and underground. Major equipment items are identified. The report includes plans for decommissioning and sealing of the facility. The report discusses how the repository will satisfy performance objectives. Chapters are included on basis for design, design analyses, and data requirements for completion of future design efforts. 105 figs., 52 tabs.

  3. FEBEX: Full-Scale engineered barriers experiment in crystalline host-rock: preoperational phase. Synthesized report; FEBEX: experimento de barreras de ingenieria a gran escala en rocas cristalinas: etapa preoperacional. Informe de sintesis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    The FEBEX project is being cofinanced by the EC under contract F 14WCT950006. In addition to the EC, seven partners from three countries of the EU. (France, Germany, and Spain) as well as one from EFTA (Switzerland) are participating in the project. ENRESA is the coordinating partner with NAGRA assisting in coordinating some aspects. The project consists of two large-scale tests and a series of complimentary laboratory tests. The work is being executed by the following organizations: CIEMAT, AITEMIN, UP-DIT (CIMNE), ULC, CSIC-Zaidin, and UPM (SPAIN) ANDRA and G.3S (FRANCE) GRS (GERMANY). This report includes a synthesized description of the experiment from its conception through the installation of the two large-scale tests (from the middle of 1994 to the beginning of 1997, preoperation stage). The experiment is described in detail in a series of specific reports. (Author)

  4. Effusion rates, volumes and emplacement style using MODIS MIR data: the 2014-15 Holuhraun eruption (Bárðarbunga, Iceland) tracked by MIROVA

    Science.gov (United States)

    Coppola, Diego; Laiolo, Marco; Cigolini, Corrado; Barsotti, Sara; Jónasdóttir, Elin; Ripepe, Maurizio

    2016-04-01

    MIROVA (Middle InfraRed Observation of Volcanic Activity) is a new volcanic hot-spot detection system, based on the near-real time analysis of infrared data acquired by the MODIS sensor (Moderate Resolution Imaging Spectroradiometer). During the Holuhraun (Bárðarbunga) eruption, which lasted from the end of August 2014 to February 2015, MIROVA has been used to detect, locate and measure the heat radiated by the evolving lava field. After peaking during the first two week of activity, the eruption produced a slow but persistent decay of MIR-derived thermal flux, that was coupled with a gradual transition from channel- to tube-fed dominated emplacement style. This was coupled with a modification of the principal growing process of the flow field that shifted from lengthening to widening and finally to thickening. Despite the evident evolution of the emplacement style our results suggest that the decreasing trend of the thermal flux was essentially controlled by the slow reduction of the effusion rates, rather than by the increasing insulation of the flow field. In fact, we provide evidence that the changing emplacement style, from channel- to tube-fed activity , did not affected (substantially) the area of radiating lava surface, but had simply a strong impact in transporting the lava farther from the vent. This suggests that during the Holuhraun eruption, as well as during many other effusive eruptions, the MIR-derived radiant flux essentially mimic the trend of lava discharge rates, with only a minor influences due to the emplacement style.

  5. The Blood-Brain Barrier: An Engineering Perspective

    Directory of Open Access Journals (Sweden)

    Andrew eWong

    2013-08-01

    Full Text Available It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich’s first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and it remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore advances in our understanding of the structure and function of the blood-brain barrier are key to advances in treatment of a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases.

  6. Subglacial lava propagation, ice melting and heat transfer during emplacement of an intermediate lava flow in the 2010 Eyjafjallajökull eruption

    Science.gov (United States)

    Oddsson, Björn; Gudmundsson, Magnús T.; Edwards, Benjamin R.; Thordarson, Thorvaldur; Magnússon, Eyjólfur; Sigurðsson, Gunnar

    2016-07-01

    During the 2010 Eyjafjallajökull eruption in South Iceland, a 3.2-km-long benmoreite lava flow was emplaced subglacially during a 17-day effusive-explosive phase from April 18 to May 4. The lava flowed to the north out of the ice-filled summit caldera down the outlet glacier Gígjökull. The flow has a vertical drop of about 700 m, an area of ca. 0.55 km2, the total lava volume is ca. 2.5·107 m3 and it is estimated to have melted 10-13·107 m3 of ice. During the first 8 days, the lava advanced slowly (caldera where the ice was 60-100 m thick. This subglacial lava flow was emplaced along meltwater tunnels under ice for the entire 3.2 km of the flow field length and constitutes 90 % of the total lava volume. The remaining 10 % belong to subaerial lava that was emplaced on top of the subglacial lava flow in an ice-free environment at the end of effusive activity, forming a 2.7 km long a'a lava field. About 45 % of the thermal energy of the subglacial lava was used for ice melting; 4 % was lost with hot water; about 1 % was released to the atmosphere as steam. Heat was mostly released by forced convection of fast-flowing meltwater with heat fluxes of 125-310 kWm-2.

  7. Tracking lava flow emplacement on the east rift zone of Kīlauea, Hawai‘i, with synthetic aperture radar coherence

    Science.gov (United States)

    Dietterich, Hannah R.; Poland, Michael P.; Schmidt, David A.; Cashman, Katharine V.; Sherrod, David R.; Espinosa, Arkin Tapia

    2012-05-01

    Lava flow mapping is both an essential component of volcano monitoring and a valuable tool for investigating lava flow behavior. Although maps are traditionally created through field surveys, remote sensing allows an extraordinary view of active lava flows while avoiding the difficulties of mapping on location. Synthetic aperture radar (SAR) imagery, in particular, can detect changes in a flow field by comparing two images collected at different times with SAR coherence. New lava flows radically alter the scattering properties of the surface, making the radar signal decorrelated in SAR coherence images. We describe a new technique, SAR Coherence Mapping (SCM), to map lava flows automatically from coherence images independent of look angle or satellite path. We use this approach to map lava flow emplacement during the Pu`u `Ō`ō-Kupaianaha eruption at Kīlauea, Hawai`i. The resulting flow maps correspond well with field mapping and better resolve the internal structure of surface flows, as well as the locations of active flow paths. However, the SCM technique is only moderately successful at mapping flows that enter vegetation, which is also often decorrelated between successive SAR images. Along with measurements of planform morphology, we are able to show that the length of time a flow stays decorrelated after initial emplacement is linearly related to the flow thickness. Finally, we use interferograms obtained after flow surfaces become correlated to show that persistent decorrelation is caused by post-emplacement flow subsidence.

  8. Emplacement of pyroclastic flows during the 1998 1999 eruption of Volcán de Colima, México

    Science.gov (United States)

    Saucedo, R.; Macías, J. L.; Bursik, M. I.; Mora, J. C.; Gavilanes, J. C.; Cortes, A.

    2002-09-01

    After three years of quiescence, Volcán de Colima reawakened with increasing seismic and rock fall activity that reached its peak on November 20, 1998, when a new lava dome forced its way to the volcano's summit. The new lava rapidly reached the S-SW edge of the summit area, beginning the generation of Merapi-type pyroclastic flows that traveled down La Lumbre, and the El Cordoban Western and Eastern ravines, reaching distances of 3, 4.5, and 3 km, respectively. On December 1, 1998, the lava flow split into three fronts that in early 1999 had reached 2.8, 3.1, and 2.5 km in length, advancing down the El Cordoban ravines. The lava flow fronts disaggregated into blocks forming pyroclastic flows. One of the best examples occurred on December 10, 1998. As the lava flow ceased moving in early 1999, activity became more explosive. Strong blasts were recorded on February 10, May 10, and July 17, 1999. The last event developed a 10-km-high eruptive column from which a pyroclastic flow developed from the base, traveling 3.3 km SW from the summit into the San Antonio-Montegrande ravines. Regardless of the mechanism of pyroclastic-flow generation, each flow immediately segregated into a basal avalanche that moved as a granular flow and an upper ash cloud in which particles were sustained in turbulent suspension. When the basal avalanche lost velocity and eventually stopped, the upper ash cloud continued to move independently as a dilute pyroclastic flow that produced a massive pyroclastic-flow deposit and an upper dune-bedded surge deposit. The dilute pyroclastic flow scorched and toppled maguey plants and trees, and sandblasted vegetation in the direction of the flow. At the end of the dilute pyroclastic-flow path, the suspended particles lifted off in a cloud from which a terminal ash fall was deposited. The basal avalanche emplaced block-and-ash flow deposits (up to 8 m thick) that filled the main ravines and consisted of several flow units. Each flow unit was massive

  9. Appinite suites: A record of the role of water in the genesis, transport, emplacement and crystallization of magma

    Science.gov (United States)

    Murphy, J. Brendan

    2013-04-01

    The appinite suite of rocks offers a unique opportunity to study the effect of water on the generation, emplacement and crystallization history of mafic to felsic magma. The suite consists of a group of coeval plutonic and/or hypabyssal rocks, ranging from ultramafic to felsic in composition in which hornblende is the dominant mafic mineral, and typically occurs both as large prismatic phenocrysts and in the finer grained matrix. The suite is also characterized by abundant evidence for mixing and mingling between diverse magma types and variable degrees of contamination by host rock. Field observations corroborate experimental and theoretical studies that the hornblende stability field expands at the expense of olivine and pyroxene with increasing pH2O in the magma. Textures characteristic of appinites are consistent with rapid growth and with experimental evidence for the reduced viscosity of melts allowing efficient migration of ions to the sites of mineral growth. The appinite suite was originally defined in the Paleozoic Caledonide orogen in Scotland, where it occurs as a number of small shallow crustal bodies that were emplaced after the cessation of subduction and in the immediate aftermath of terrane collision and closure of the Iapetus Ocean. The mafic component is thought to have been triggered by asthenospheric upwelling following stab break-off, and magmas produced have both juvenile and sub-continental lithospheric mantle components. Its compositions have affinities with shoshonites. The felsic components include large batholiths that were probably derived by fractional crystallization. Other appinite suites share some, but not all of these characteristics. Appinite suites apparently range in age from Neo-Archean to Recent, and occur at all crustal levels, at depths of up to 40 km. In addition to shoshonites, appinite suites share some similar geochemical features with high-Mg andesites, sanukitoids and adakites. Some common tectonic traits include a

  10. Filaggrin and Skin Barrier Function.

    Science.gov (United States)

    Kezic, Sanja; Jakasa, Ivone

    2016-01-01

    The skin barrier function is greatly dependent on the structure and composition of the uppermost layer of the epidermis, the stratum corneum (SC), which is made up of flattened anucleated cells surrounded by highly organized and continuous lipid matrix. The interior of the corneocytes consists mainly of keratin filaments aggregated by filaggrin (FLG) protein. Next, together with several other proteins, FLG is cross-linked into a mechanically robust cornified cell envelope providing a scaffold for the extracellular lipid matrix. In addition to its role for the SC structural and mechanical integrity, FLG degradation products account in part for the water-holding capacity and maintenance of acidic pH of the SC, both crucial for the epidermal barrier homoeostasis by regulating activity of multiple enzymes that control desquamation, lipid synthesis and inflammation. The major determinant of FLG expression in the skin are loss-of-function mutations in FLG, the strongest genetic risk factor for atopic dermatitis (AD), an inflammatory skin disease characterized by a reduced skin barrier function. The prevalence of FLG mutations varies greatly among different populations and ranges from about 10% in Northern Europeans to less than 1% in the African populations. An impaired skin barrier facilitates absorption of potentially hazardous chemicals, which might cause adverse effects in the skin, such as contact dermatitis, or systemic toxicity after their passage into blood. In another direction, a leaky epidermal barrier will lead to enhanced loss of water from the skin. A recent study has shown that even subtle increase in epidermal water loss in newborns increases the risk for AD. Although there are multiple modes of action by which FLG might affect skin barrier it is still unclear whether and how FLG deficiency leads to the reduced skin barrier function. This chapter summarizes the current knowledge in this field obtained from clinical studies, and animal and in vitro models

  11. Yellowstone plume trigger for Basin and Range extension and emplacement of the Nevada-Columbia Basin magmatic belt

    Science.gov (United States)

    Camp, Victor E; Pierce, Kenneth L.; Morgan Morzel, Lisa Ann.

    2015-01-01

    Widespread extension began across the northern and central Basin and Range Province at 17–16 Ma, contemporaneous with magmatism along the Nevada–Columbia Basin magmatic belt, a linear zone of dikes and volcanic centers that extends for >1000 km, from southern Nevada to the Columbia Basin of eastern Washington. This belt was generated above an elongated sublithospheric melt zone associated with arrival of the Yellowstone mantle plume, with a north-south tabular shape attributed to plume ascent through a propagating fracture in the Juan de Fuca slab. Dike orientation along the magmatic belt suggests an extension direction of 245°–250°, but this trend lies oblique to the regional extension direction of 280°–300° during coeval and younger Basin and Range faulting, an ∼45° difference. Field relationships suggest that this magmatic trend was not controlled by regional stress in the upper crust, but rather by magma overpressure from below and forceful dike injection with an orientation inherited from a deeper process in the sublithospheric mantle. The southern half of the elongated zone of mantle upwelling was emplaced beneath a cratonic lithosphere with an elevated surface derived from Late Cretaceous to mid-Tertiary crustal thickening. This high Nevadaplano was primed for collapse with high gravitational potential energy under the influence of regional stress, partly derived from boundary forces due to Pacific–North American plate interaction. Plume arrival at 17–16 Ma resulted in advective thermal weakening of the lithosphere, mantle traction, delamination, and added buoyancy to the northern and central Basin and Range. It was not the sole cause of Basin and Range extension, but rather the catalyst for extension of the Nevadaplano, which was already on the verge of regional collapse.

  12. Hematite-bearing materials surrounding Candor Mensa in Candor Chasma, Mars: Implications for hematite origin and post-emplacement modification

    Science.gov (United States)

    Fergason, R. L.; Gaddis, L. R.; Rogers, A. D.

    2014-07-01

    The Valles Marineris canyon system on Mars is of enduring scientific interest in part due to the presence of interior mounds that contain extensive layering and water-altered minerals, such as crystalline gray hematite and hydrated sulfates. The presence of hematite and hydrated sulfate minerals is important because their host rock lithologies provide information about past environments that may have supported liquid water and may have been habitable. This work further defines the association and relationship between hematite-bearing materials and low albedo (presumably aeolian) deposits and layered materials, identifies physical characteristics that are strongly correlated with the presence of hematite, and refines hypotheses for the origin and post-emplacement modification (including transport) of these hematite-bearing and associated materials. There are only three regions surrounding Candor Mensa where hematite has been identified, even though morphologic properties are similar throughout the entire mensa. Three possible explanations for why hematite is only exposed in these regions include: (1) the topographic structure of the mensa walls concentrates hematite at the base of the layered deposits, influencing the ability to detect hematite from orbit; (2) the presence of differing amounts of “dark mantling material” and hematite-free erosional sediment; (3) the potential fracturing of the mensa and the influence of these structures on fluid flow and subsequent digenesis. The observations of hematite-bearing materials in this work support the hypothesis that hematite is eroding from a unit in the Candor Mensa interior layered deposits (ILD) and is being concentrated as a lag deposit adjacent to the lower layers of Candor Mensa and at the base in the form of dark aeolian material. Due to the similar geologic context associated with hematite-bearing and ILD materials throughout the Valles Marineris canyon system, the insight gained from studying these

  13. Monitoring Inflation and Emplacement During the 2014-2015 Kilauea Lava Flow With an Unmanned Aerial Vehicle

    Science.gov (United States)

    Perroy, R. L.; Turner, N.; Hon, K. A.; Rasgado, V.

    2015-12-01

    Unmanned aerial vehicles (UAVs) provide a powerful new tool for collecting high resolution on-demand spatial data over volcanic eruptions and other active geomorphic processes. These data can be used to improve hazard forecasts and emergency response efforts, and also allow users to economically and safely observe and quantify lava flow inflation and emplacement on spatially and temporally useful scales. We used a small fixed-wing UAV with a modified point-and-shoot camera to repeatedly map the active front of the 2014-2015 Kīlauea lava flow over a one-month period in late 2014, at times with a two-hour repeat interval. An additional subsequent flight was added in July, 2015. We used the imagery from these flights to generate a time-series of 5-cm resolution RGB and near-infrared orthoimagery mosaics and associated digital surface models using structure from motion. Survey-grade positional control was provided by ground control points with differential GPS. Two topographic transects were repeatedly surveyed across the flow surface, contemporaneously with UAV flights, to independently confirm topographic changes observed in the UAV-derived surface models. Vertical errors were generally 10 cm. Inside our 50 hectare study site, the flow advanced at a rate of 0.47 hectares/day during the first three weeks of observations before abruptly stalling out inflation >4 m. New outbreak areas, both on the existing flow surface and along the flow margins, were readily mapped across the study area. We detected sinuous growing inflation ridges within the flow surface that correlated with subsequent outbreaks of new lava, suggesting that repeat UAV flights can provide a means of better predicting pahoehoe lava flow behavior over flat or uneven topography. Our results show that UAVs can generate accurate and digital surface models quickly and inexpensively over rapidly changing active pahoehoe lava flows.

  14. Hematite-bearing materials surrounding Candor Mensa in Candor Chasma, Mars: Implications for hematite origin and post-emplacement modification

    Science.gov (United States)

    Fergason, Robin L.; Gaddis, Lisa R.; Rogers, A. D.

    2014-01-01

    The Valles Marineris canyon system on Mars is of enduring scientific interest in part due to the presence of interior mounds that contain extensive layering and water-altered minerals, such as crystalline gray hematite and hydrated sulfates. The presence of hematite and hydrated sulfate minerals is important because their host rock lithologies provide information about past environments that may have supported liquid water and may have been habitable. This work further defines the association and relationship between hematite-bearing materials and low albedo (presumably aeolian) deposits and layered materials, identifies physical characteristics that are strongly correlated with the presence of hematite, and refines hypotheses for the origin and post-emplacement modification (including transport) of these hematite-bearing and associated materials. There are only three regions surrounding Candor Mensa where hematite has been identified, even though morphologic properties are similar throughout the entire mensa. Three possible explanations for why hematite is only exposed in these regions include: (1) the topographic structure of the mensa walls concentrates hematite at the base of the layered deposits, influencing the ability to detect hematite from orbit; (2) the presence of differing amounts of “dark mantling material” and hematite-free erosional sediment; (3) the potential fracturing of the mensa and the influence of these structures on fluid flow and subsequent digenesis. The observations of hematite-bearing materials in this work support the hypothesis that hematite is eroding from a unit in the Candor Mensa interior layered deposits (ILD) and is being concentrated as a lag deposit adjacent to the lower layers of Candor Mensa and at the base in the form of dark aeolian material. Due to the similar geologic context associated with hematite-bearing and ILD materials throughout the Valles Marineris canyon system, the insight gained from studying these

  15. The emplacement history of a remarkable heterogeneous, chemically zoned, rheomorphic and locally lava-like ignimbrite: 'TL' on Gran Canaria

    Science.gov (United States)

    Sumner, Janet M.; Branney, Michael J.

    2002-06-01

    Ignimbrite 'TL' on Gran Canaria is a complex, compositionally zoned rheomorphic tuff, that locally exhibits features previously considered to be diagnostic of lavas. It is made up of two locally overlapping lobes of ignimbrite that were emplaced during a single eruptive episode. The eastern lobe is high-grade, with rheomorphic zones and localised patches that are lava-like. The western lobe is extremely high-grade, more extensively lava-like, and welded to its top surface. Both parts are zoned, with a basal comendite-rich zone grading up, through a mixed zone, into an upper trachyte-rich zone. Lithic contents, and the relative proportions of comendite and trachyte pyroclasts vary with height. Each comendite-rich zone is vitroclastic, whereas each trachyte-rich zone is partly lava-like with local gradations into vitroclastic ignimbrite. Mixed zones are intermediate in character, and locally show compositional banding. Gradational zoning in massive ignimbrite, best seen in lower strain zones, and welding fabrics that are pervasively lineated and oblique to bedding, suggest that deposition was sustained, agglutination was rapid, and rheomorphic deformation began during the sustained deposition. The viscosity and porosity of the agglutinate varied with height because successively deposited pyroclast populations varied in grainsize, composition and temperature. The hot agglutinate continued to compact and shear downslope after the density currents had dissipated, causing further rheomorphic folding, thrusting, attenuation and autobrecciation. The western lobe locally overlies the partly welded top of the eastern lobe, in part because it advanced rheomorphically across it for at least 300 m. Hot-state loading and auto-intrusion occurred due to unstable density layering in the chemically zoned agglutinate. Deformation behaviour changed during cooling and degassing, and because of heat transfer between juxtaposed agglutinates, and localised retention of dissolved volatiles

  16. Slab melting, adakite differentiation and emplacement in a fossile subduction channel: the late Paleocene Sabzevar magmatism (NE Iran)

    Science.gov (United States)

    Rossetti, Federico; Nasrabady, Mohsen; Gerdes, Axel; Moniè, Patrick; Theye, Thomas; Lucci, Federico; Vignaroli, Gianluca

    2014-05-01

    This study describes the structural setting, petrogenesis, and geochronology of a suite of acidic magmatic rocks that are intruded in the metamorphic core of the Tertiary ophiolitic suture zone of the Sabzevar Range, NE central Iran. This ophiolitic complex consists of a ductile-to-brittle, S/SE-verging orogenic domain, where a frontal nonmetamorphic and an inner metamorphic sector can be identified in the field. The metamorphic domain consists of a major ophiolitic tectonic mélange, where variably sized, foliated metabasic rocks (blueschists, greenschists, and amphibolites) occur dispersed as centimetre- to kilometre-size blocks into a highly sheared serpentinite matrix. The granitoids occur as leucocratic tabular bodies, with variably developed contact metamorphic zones that are typically gradational in the field and concordant with the regional country rock foliation. The field relations with the host rocks and the internal (magmatic to solid state) fabrics in the Sabzevar granitoids document a syntectonic magma emplacement scenario, based on: (1) concordance of pluton shapes and internal structures with regional structures (S-L fabrics); (2) the existence of a continuum of magmatic through solid-state noncoaxial flow consistent with the regional sense of shear (top-to-the-SSE); and (3) occurrence of foliated wall-rock xenoliths, incorporated by flowing magma into the marginal sectors of the intrusive bodies. These points, together with the evidence that magma preferentially migrated along flats, attest that the Sabzevar granitoids intruded into rocks that were actively deforming during compressional shearing. In the TAS diagram, the granitoid compositions define a medium-K calc-alkaline suite, spanning from basaltic andesite to the dacite and rhyolite fields. They show characteristic low MgO (0.15-0.60 wt%) and Ni (

  17. Emplacement of Bela and Muslim Bagh Ophiolites and Significance of India-Asia Collision in Western Pakistan

    Science.gov (United States)

    Xiong, Yingqian

    The collision of India with Asia is an important geologic event preceded by the formation of now obducted ophiolites of Western Pakistan. Ophiolites along the suture zone between India and Asia can help elucidate the pre-terminal and terminal collisional history of the Himalaya orogen. Along the western boundary of the Indian plate, the Bela Ophiolite (BO) and associated allochthonous Sub-Ophiolitic Volcanic Complexes (BSOVC) represent the largest composite exposures of mafic and ultramafic rocks. The Muslim Bagh Ophiolite (MBO) is another well-known ophiolite. Collectively, they have not been extensively studied because of their remote location. A detailed geological map for the BO-BSOVC was created using remote sensing and field data. False-color images (Landsat ETM+ bands 7-4-2 in RGB), color band-ratio composite images of Landsat ETM+ data (5/7-5/1-5/4 in RGB), ASTER data (4/5-6/7-3/4 in RGB), and Mafic Index images along with reflectance spectroscopy data were used to discriminate different lithologies. Based on the geochemistry, age, and tectonic contact relationships of the samples analyzed, the BO most likely formed in an oceanic supra-subduction forearc environment ˜65 Ma on the upper plate of a westward-dipping subduction zone that consumed Indian plate oceanic crust. The alkali basalts trace elements signatures from the BSOVC show OIB signatures. They are likely to be from seamount complexes that were part of the subducting Indian plate. Analyzed dike samples from the MBO show typical subduction-related trace element signatures on a chondrite-normalized diagram and in a Th-Hf/3-Ta ternary diagram. The island arc affinity for the diabase dikes cutting the mantle section and sheeted dikes indicates that their origin could be analogous to some segments of the Chile ridge. An island arc affinity for dikes cutting the metamorphic sole indicates that emplacement of the MBO was followed by island arc-type magmatism.

  18. The Calama-Olacapato-El Toro fault system in the Puna Plateau, Central Andes: Geodynamic implications and stratovolcanoes emplacement

    Science.gov (United States)

    Norini, Gianluca; Baez, Walter; Becchio, Raul; Viramonte, Jose; Giordano, Guido; Arnosio, Marcelo; Pinton, Annamaria; Groppelli, Gianluca

    2013-11-01

    The structural evolution of the Puna Plateau is characterized by the activity of both orogen-parallel and orogen-oblique faults. Understanding the possible relationship between these two structural styles, their geodynamic implications and the influence on the migration of magmas is important to get insights into the tectonic and magmatic evolution of the Central Andes. In this study, we present a structural analysis of the orogen-oblique Calama-Olacapato-El Toro fault system and the surrounding orogen-parallel thrust faults in the central-eastern Puna Plateau. Morphostructural analysis and field mapping reveal the geometry, kinematics and dynamics of the tectonic features in the studied area. We propose a three-dimensional geometrical reconstruction of the main fault planes showing their attitude and intersections at depth. The study indicates that the crust underwent simultaneous deformation along both the vertical transcurrent Calama-Olacapato-El Toro fault system and the low-angle thrust faults, and that the back-arc portion of the Calama-Olacapato-El Toro fault system developed as a transfer zone among the main N-striking thrusts. Our model considers that both orogen-parallel and orogen-oblique fault systems should be regarded as parts of the same tectonic system, accommodating crustal shortening of a thickened crust. The study suggests that the tectonic control on the magma and fluid circulation in the crust is mainly related to the geometry of the fault planes and the orientation of the stress field, with a previously unrecognized important role played by the orogen-parallel thrust faults on the emplacement of the stratovolcanoes.

  19. The significance of late-stage processes in lava flow emplacement: squeeze-ups in the 2001 Etna flow field

    Science.gov (United States)

    Applegarth, L. J.; Pinkerton, H.; James, M. R.

    2009-04-01

    The general processes associated with the formation and activity of ephemeral boccas in lava flow fields are well documented (e.g. Pinkerton & Sparks 1976; Polacci & Papale 1997). The importance of studying such behaviour is illustrated by observations of the emplacement of a basaltic andesite flow at Parícutin during the 1940s. Following a pause in advance of one month, this 8 km long flow was reactivated by the resumption of supply from the vent, which forced the rapid drainage of stagnant material in the flow front region. The material extruded during drainage was in a highly plastic state (Krauskopf 1948), and its displacement allowed hot fluid lava from the vent to be transported in a tube to the original flow front, from where it covered an area of 350,000 m2 in one night (Luhr & Simkin 1993). Determining when a flow has stopped advancing, and cannot be drained in such a manner, is therefore highly important in hazard assessment and flow modelling, and our ability to do this may be improved through the examination of relatively small-scale secondary extrusions and boccas. The 2001 flank eruption of Mt. Etna, Sicily, resulted in the emplacement of a 7 km long compound `a`ā flow field over a period of 23 days. During emplacement, many ephemeral boccas were observed in the flow field, which were active for between two and at least nine days. The longer-lived examples initially fed well-established flows that channelled fresh material from the main vent. With time, as activity waned, the nature of the extruded material changed. The latest stages of development of all boccas involved the very slow extrusion of material that was either draining from higher parts of the flow or being forced out of the flow interior as changing local flow conditions pressurised parts of the flow that had been stagnant for some time. Here we describe this late-stage activity of the ephemeral boccas, which resulted in the formation of ‘squeeze-ups' of lava with a markedly different

  20. Thermal fission rates with temperature dependent fission barriers

    Science.gov (United States)

    Zhu, Yi; Pei, J. C.

    2016-08-01

    Background: The fission processes of thermal excited nuclei are conventionally studied by statistical models which rely on inputs of phenomenological level densities and potential barriers. Therefore the microscopic descriptions of spontaneous fission and induced fission are very desirable for a unified understanding of various fission processes. Purpose: We propose to study the fission rates, at both low and high temperatures, with microscopically calculated temperature-dependent fission barriers and collective mass parameters. Methods: The fission barriers are calculated by the finite-temperature Skyrme-Hartree-Fock+BCS method. The mass parameters are calculated by the temperature-dependent cranking approximation. The thermal fission rates can be obtained by the imaginary free energy approach at all temperatures, in which fission barriers are naturally temperature dependent. The fission at low temperatures can be described mainly as a barrier-tunneling process. While the fission at high temperatures has to incorporate the reflection above barriers. Results: Our results of spontaneous fission rates reasonably agree with other studies and experiments. The temperature dependencies of fission barrier heights and curvatures have been discussed. The temperature dependent behaviors of mass parameters have also been discussed. The thermal fission rates from low to high temperatures with a smooth connection have been given by different approaches. Conclusions: Since the temperature dependencies of fission barrier heights and curvatures, and the mass parameters can vary rapidly for different nuclei, the microscopic descriptions of thermal fission rates are very valuable. Our studies without free parameters provide a consistent picture to study various fissions such as that in fast-neutron reactors, astrophysical environments, and fusion reactions for superheavy nuclei.

  1. Government regulation of business in a changing institutional barrier

    Directory of Open Access Journals (Sweden)

    Novikova I.

    2013-02-01

    Full Text Available The article examines the domestic experience in government regulation of business in a changing institutional barrier.Compared the degree of economic freedom in Ukraine. The emphasis is on the need to develop a national strategy of institutional development of domestic entrepreneurship.

  2. Asian American Educational Goals: Racial Barriers and Cultural Factors

    Science.gov (United States)

    Chen, Yung-Lung; Fouad, Nadya A.

    2013-01-01

    Educational success among Asian American students has often been misunderstood as an occupational development separate from any experience of racism. However, several theorists have suggested that racial barriers in occupational mobility correlate with educational pursuits. Therefore, this research aims to examine the direct effect of perceived…

  3. EMPLACEMENT DRIFT SHIELDING CALCULATION

    Energy Technology Data Exchange (ETDEWEB)

    A. Nielsen

    1999-10-13

    The purpose of this analysis is to determine the structural response of a TRIGA Department of Energy (DOE) spent nuclear fuel (SNF) codisposal canister placed in a 5-Defense High Level Waste (DHLW) waste package (WP) and subjected to a tipover design basis event (DBE) dynamic load; the results will be reported in terms of displacements and stress magnitudes. This activity is associated with the WP design.

  4. Cylindrical air flow reversal barrier

    Energy Technology Data Exchange (ETDEWEB)

    Woznica, C.; Rodziewicz, M.

    1988-06-01

    Describes an innovative design introduced in the ZMP mine in Zory for quick reversal of ventilation air flow. Geologic mining conditions at the 705 m deep horizon, where the barrier was built, are described. According to the design used until now, a reversal system consisted of safety barriers, ventilation air locks, a ventilation bridge and stopping needed in case of a fire when air flow direction must be reversed. Nine air locks and an expensive concrete ventilation bridge were needed and the air locks had to be operated at 8 points of the region to effect reversal. The new design consists of a 2-storey cylindrical barrier which also fulfills the function of a ventilation bridge. It can be manually or remotely operated by a mechanical or pneumatic system. Tests showed that the new barrier permits immediate air flow reversal while retaining 60% of the original air, which is important in the case of fire and methane hazards. It permits improved seam panelling and splitting of pillars and brings an economy of about 40 million zlotys in construction cost. Design and operation of the barrier is illustrated and ventilation air circulation is explained. 7 figs.

  5. Use of natural gas on heavy duty vehicles in Brazil: experience, current scene and barriers that still persist; Utilizacao do gas natural em veiculos pesados no Brasil: experiencia, cenario atual e barreiras que ainda persistem

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Guilherme B.; Melo, Tadeu C.C.; Lastres, Luiz Fernando M. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    In the 80's, because of the oil crisis, the Natural Gas (NG) appeared as a fuel with a great potential for Diesel replacement in Heavy Duty Vehicles. At that time, PETROBRAS with other companies have developed partial conversion technologies from Diesel to NG, known as 'Dual Fuel'. Engine dynamometer and vehicle bus tests have been developed to verify its technical and economical viability. Because of several factors, the Dual Fuel Program did not advance and the experience was interrupted. At the same time, other experiences using NG Otto Cycle bus engines, manufactured in Brazil, have been conducted, mainly at Sao Paulo, nevertheless, without expansion. Currently, factors as increase of the NG converted light vehicles fleet; the NG excess in the National Market, which has contributed to the NG distribution net expansion; the Environmental Legislature in vigor, that continuously determine lower emission limits; the government interest in increasing the NG energy matrix share and in reducing Diesel fuel consumption, and the low NG industrial demand, compose together a great scene to the diffusion of NG as substitute to the Diesel fuel in Heavy Duty Vehicles. (author)

  6. Barriers to Sexuality for Individuals with Intellectual and Developmental Disabilities: A Literature Review

    Science.gov (United States)

    Sinclair, James; Unruh, Deanne; Lindstrom, Lauren; Scanlon, David

    2015-01-01

    Individuals with intellectual and developmental disabilities (ID/DD) experience multiple barriers that may prevent them from understanding and exploring their own sexuality. These barriers prevent them from achieving the same autonomy and quality of life as their peers. This research synthesis focuses on 13 articles published between 2000 and 2013…

  7. Post-emplacement cooling and contraction of lava flows: InSAR observations and thermal model for lava fields at Hekla volcano, Iceland

    Science.gov (United States)

    Wittmann, Werner; Dumont, Stephanie; Lavallee, Yan; Sigmundsson, Freysteinn

    2016-04-01

    Gradual post-emplacement subsidence of lava flows has been observed at various volcanoes, e.g. Okmok volcano in Alaska, Kilauea volcano on Hawaii and Etna volcano on Sicily. In Iceland, this effect has been observed at Krafla volcano and Hekla volcano. The latter was chosen as a case study for investigating subsidence mechanisms, specifically thermal contraction. Effects like gravitational loading, clast repacking or creeping of a hot and liquid core can contribute to subsidence of emplaced lava flows, but thermal contraction is considered being a crucial effect. The extent to which it contributes to lava flow subsidence is investigated by mapping the relative movement of emplaced lava flows and flow substrate, and modeling the observed signal. The slow vegetation in Iceland is advantageous for Interferometric Synthetic Aperture Radar (InSAR) and offers great coherence over long periods after lava emplacement, expanding beyond the outlines of lava flows. Due to this reason, InSAR observations over volcanoes in Iceland have taken place for more than 20 years. By combining InSAR tracks from ERS, Envisat and Cosmo-SkyMed satellites we gain six time series with a total of 99 interferograms. Making use of the high spatial resolution, a temporal trend of vertical lava movements was investigated over a course of over 23 years over the 1991 lava flow of Hekla volcano, Iceland. From these time series, temporal trends of accumulated subsidence and subsidence velocities were determined in line of sight of the satellites. However, the deformation signal of lava fields after emplacement is vertically dominated. Subsidence on this lava field is still ongoing and subsidence rates vary from 14.8 mm/year in 1995 to about 1.0 mm/year in 2014. Fitting a simple exponential function suggests a exponential decay constant of 5.95 years. Additionally, a one-dimensional, semi-analytical model was fitted to these data. While subsidence due to phase change is calculated analytically

  8. Using models to interpret the impact of roadside barriers on near-road air quality

    Science.gov (United States)

    Amini, Seyedmorteza; Ahangar, Faraz Enayati; Schulte, Nico; Venkatram, Akula

    2016-08-01

    The question this paper addresses is whether semi-empirical dispersion models based on data from controlled wind tunnel and tracer experiments can describe data collected downwind of a sound barrier next to a real-world urban highway. Both models are based on the mixed wake model described in Schulte et al. (2014). The first neglects the effects of stability on dispersion, and the second accounts for reduced entrainment into the wake of the barrier under unstable conditions. The models were evaluated with data collected downwind of a kilometer-long barrier next to the I-215 freeway running next to the University of California campus in Riverside. The data included measurements of 1) ultrafine particle (UFP) concentrations at several distances from the barrier, 2) micrometeorological variables upwind and downwind of the barrier, and 3) traffic flow separated by automobiles and trucks. Because the emission factor for UFP is highly uncertain, we treated it as a model parameter whose value is obtained by fitting model estimates to observations of UFP concentrations measured at distances where the barrier impact is not dominant. Both models provide adequate descriptions of both the magnitude and the spatial variation of observed concentrations. The good performance of the models reinforces the conclusion from Schulte et al. (2014) that the presence of the barrier is equivalent to shifting the line sources on the road upwind by a distance of about HU/u∗ where H is the barrier height, U is the wind velocity at half of the barrier height, and u∗ is the friction velocity. The models predict that a 4 m barrier results in a 35% reduction in average concentration within 40 m (10 times the barrier height) of the barrier, relative to the no-barrier site. This concentration reduction is 55% if the barrier height is doubled.

  9. Emplacement dynamics and lava field evolution of the flood basalt eruption at Holuhraun, Iceland: Observations from field and remote sensing data

    Science.gov (United States)

    Pedersen, Gro; Höskuldsson, Armann; Riishuus, Morten S.; Jónsdóttir, Ingibjörg; Thórdarson, Thorvaldur; Dürig, Tobias; Gudmundsson, Magnus T.; Durmont, Stephanie

    2016-04-01

    The Holuhraun eruption (Aug 2014- Feb 2015) is the largest effusive eruption in Iceland since the Laki eruption in 1783-84, with an estimated lava volume of ~1.6 km3 covering an area of ~83 km2. The eruption provides an unprecedented opportunity to study i) lava morphologies and their emplacement styles, ii) Morphological transitions iii) the transition from open to closed lava pathways and iv) the implication of lava pond formation. This study is based on three different categories of data; field data, airborne data and satellite data. The field data include tracking of the lava advancement by Global Positioning System (GPS) measurements and georeferenced GoPro cameras allowing classification of the lava margin morphology. Furthermore, video footage on-site documented lava emplacement. Complimentary observations have been provided from aircraft platforms and by satellite data. Of particular importance for lava morphology observations are 1-12 m/pixel airborne Synthetic Aperture Radar (SAR) images (x-band), as well as SAR data from TerraSAR-X and COSMO-SkyMed satellites. The Holuhraun lava field comprises a continuum of morphologies from pāhoehoe to 'a'ā, which have varied temporally and spatially. Shelly pāhoehoe lava was the first morphology to be observed (08-29). Spatially, this lava type was not widely distributed, but was emplaced throughout the eruption close to the vent area and the lava channels. Slabby pāhoehoe lava was initially observed the 08-31 and was observed throughout most of the eruption during the high-lava-flux phase of new lava lobe emplacement. 'A'ā lavas were the dominating morphology the first three months of the eruption and was first observed 09-01 like Rubbly pāhoehoe lava. Finally, Spiny pāhoehoe lava was first observed the 09-05 as a few marginal outbreaks along the fairly inactive parts of the 'a'ā lava lobe. However, throughout the eruption this morphology became more important and from mid-November/beginning of December the

  10. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    S V S Sastry; S Santra

    2000-06-01

    It is shown that the analysis of fusion barrier distributions is not always an unambiguous test or a ‘fingerprint’ of the structure information of the colliding nuclei. Examples are presented with same fusion barrier distributions for nuclei having different structures. The fusion excitation functions for 16O+208Pb, using the coupled reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable effects on the fusion excitation function. However, a simultaneous analysis of the fusion, elastic and quasi-elastic channels would fix the structure and the reaction unambiguously

  11. Skin Barrier Function and Allergens

    DEFF Research Database (Denmark)

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan

    2016-01-01

    The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization...... and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due......) and Th2 (AD) have been proposed as an explanation. Finally, there is convincing evidence that exposure to irritants increases the risk of CS, and patients with ICD are, therefore, at great risk of developing CA. Skin irritation leads to the release of IL-1 and TNF-α, which affects the function of antigen...

  12. See-through multi-view 3D display with parallax barrier

    Science.gov (United States)

    Hong, Jong-Young; Lee, Chang-Kun; Park, Soon-gi; Kim, Jonghyun; Cha, Kyung-Hoon; Kang, Ki Hyung; Lee, Byoungho

    2016-03-01

    In this paper, we propose the see-through parallax barrier type multi-view display with transparent liquid crystal display (LCD). The transparency of LCD is realized by detaching the backlight unit. The number of views in the proposed system is minimized to enlarge the aperture size of parallax barrier, which determines the transparency. For compensating the shortness of the number of viewpoints, eye tracking method is applied to provide large number of views and vertical parallax. Through experiments, a prototype of see-through autostereoscopic 3D display with parallax barrier is implemented, and the system parameters of transmittance, crosstalk, and barrier structure perception are analyzed.

  13. Sound propagation over curved barriers

    Science.gov (United States)

    Pierce, Allan D.; Main, Geoffrey L.; Kearns, James A.; Hsieh, H.-A.

    1986-01-01

    Wide barriers with curved tops are studied with emphasis placed on circumstances whereby the local radius of curvature R of the barrier is continuous along the surface and is large compared to a wavelength. Results analogous to those given by Hayek et al. (1978) are reviewed and extended to cases where the radius of curvature and the surface impedance may vary with position. Circumstances not easily interpreted within the framework of the model proposed by Keller (1956) and Hayek et al. are also considered.

  14. The Blood-Brain Barrier: An Engineering Perspective

    OpenAIRE

    Andrew eWong; Mao eYe; Amanda eLevy; Jeffrey eRothstein; Dwight eBergles; Peter Charles Searson

    2013-01-01

    It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich’s first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and it remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier...

  15. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  16. Expectations of barriers to psychosocial care: views of parents and adolescents in the community.

    Science.gov (United States)

    Nanninga, Marieke; Reijneveld, Sijmen A; Knorth, Erik J; Jansen, Danielle E M C

    2016-01-01

    Parents with a child suffering from psychosocial problems frequently experience barriers to psychosocial care, which may hinder access. Expectations of barriers may have the same effect, but evidence is lacking. The aim of this study is to examine parents' and adolescents' expectations of barriers regarding psychosocial care for the child, along with associated child and family characteristics. We obtained data on an age-stratified random sample of school children/pupils aged 4-18 via questionnaires (N = 666; response rate 70.3 %). Expectations of barriers to psychosocial care were measured with the "Barriers to Treatment Participation Scale-Expectancies" questionnaire (BTPS-exp). Results showed that 64 % of the parents of children below age 12, 59 % of the parents of adolescents (age 12-18), and 84 % of the adolescents expected one or more barriers. Parents and adolescents expected barriers most frequently with respect to irrelevance of treatment. Mainly parents with low educational level and their adolescents expected barriers regarding treatment, and quite a few characteristics of parents of adolescents were associated with expecting multiple barriers regarding treatment demands and issues, for example, single parents, parents of lower educational level and of adolescent boys, and parents of adolescents with psychosocial problems. We conclude that adolescents especially, but also their parents and parents of younger children, expect major barriers to psychosocial care, which may greatly hinder appropriate care seeking. This evidence may support professionals and policymakers in their attempts to improve access to psychosocial care.

  17. Reactive barriers for 137Cs retention.

    Science.gov (United States)

    Krumhansl, J L; Brady, P V; Anderson, H L

    2001-02-01

    137Cs was dispersed globally by cold war activities and, more recently, by the Chernobyl accident. Engineered extraction of 137Cs from soils and groundwaters is exceedingly difficult. Because the half-life of 137Cs is only 30.2 years, remediation might be more effective (and less costly) if 137Cs bioavailability could be demonstrably limited for even a few decades by use of a reactive barrier. Essentially permanent isolation must be demonstrated in those few settings where high nuclear level wastes contaminated the environment with 135Cs (half-life 2.3 x 10(6) years) in addition to 137Cs. Clays are potentially a low-cost barrier to Cs movement, though their long-term effectiveness remains untested. To identify optimal clays for Cs retention, Cs desorption was measured for five common clays: Wyoming Montmorillonite (SWy-1), Georgia Kaolinites (KGa-1 and KGa-2), Fithian Illite (F-Ill), and K-Metabentonite (K-Mbt). Exchange sites were pre-saturated with 0.16 M CsCl for 14 days and readily exchangeable Cs was removed by a series of LiNO3 and LiCl washes. Washed clays were then placed into dialysis bags and the Cs release to the deionized water outside the bags measured. Release rates from 75 to 139 days for SWy-1, K-Mbt and F-Ill were similar; 0.017% to 0.021% sorbed Cs released per day. Both kaolinites released Cs more rapidly (0.12% to 0.05% of the sorbed Cs per day). In a second set of experiments, clays were Cs-doped for 110 days and subjected to an extreme and prolonged rinsing process. All the clays exhibited some capacity for irreversible Cs uptake. However, the residual loading was greatest on K-Mbt (approximately 0.33 wt.% Cs). Thus, this clay would be the optimal material for constructing artifical reactive barriers.

  18. Breaking the race barrier.

    Science.gov (United States)

    Minrath, M

    1985-08-01

    Through the reflective process of analyzing one's own feelings and reactions to the ethnic minority patient, the white therapist develops an inner clarity that serves as a resource to cope with the unique conflicts one must confront in interracial practice. Only when the therapist has come to some resolution of his or her own feelings about the plight of ethnic minorities in this country can this acumen develop. Although the therapeutic skills applied in psychotherapy with ethnic minorities are in no way different from overall therapeutic skills, certain techniques may be especially useful in interracial practice. For instance, a discussion of the meaning of race and ethnicity in the relationship may curtail racial distortion, prevent stereotyping, and lead to the creation of a therapeutic alliance. When dealing with transference and countertransference issues, the therapist must be particularly attentive to the representation of these same distortions and stereotypes. Formulating clinical problems from dual perspectives, theoretical and sociocultural, is an arduous, but necessary task. Finally, the white therapist must be able to view ethnic minority patients as individuals. Although these patients cope with special problems which must be acknowledged and dealt with in therapy, the therapist must realize there is a common ground on which to communicate. On this common ground, therapists discover the foundation of interracial clinical practice is the ability to accept and respect their patients and themselves as individuals who may have similar anxieties, problems, experiences, and goals. It is through the recognition and sharing of the fundamental human bond that ethnic and racial differences, which may have detrimental effects on interpersonal relationships, are transcended.

  19. Emplacement Ages and Geochemical Characteristics of Grabbroic Intrusions and Prospecting Orientation of Related Deposit in Luodian, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    FANG Weixuan; HU Ruizhong; SU Wenchao; XIAO Jiafei

    2008-01-01

    Emplacement ages, geochemical characteristics and analysis of continental dynamics ongabbroic intrusions in Luodian County, Guizhou Province, have been discussed based on studies ofisotopic chronology (the whole-rock Sm-Nd and Rb-Sr isochron methods), major elements, traceelements and PGE. Intrusive activities of the gabbroic intrusions in the study area took place during theLate Yanshanian Orogenic Movement (the Cretaceous Period), as indicated by the Sm-Nd isochronages (t)=(99.6±4.5) (2σ) Ma and by the Rb-Sr isochron ages t=(97±1.6) (2o) Ma. The gabbroic intrusionsare attached to mafic rocks in cal-alkaline basaltic series. They occurred as dikes and might be formedunder an extensional background of the continent. Differentiation of their magmatic crystallizationresulted in obvious zonation of petrography. In the gabbroic intrusions of this study, large ion lithophileelements and LREE are enriched, and the chondrite-normalized REE distribution pattern is leftwardinclined without anomalies of δCe or δEu, and there are high concentrations of PGE and ratios of Pd/Ir(averaging 4.21). All of these imply that their source areas may be basaltic magma in the upper mantlewith high-level partial melting, derived from EMl-type enriched mantle. It is different from Emeishanbasalt, which may be related to the upper mantle at low-grade partial melting. Emplacementmechanism of the gabbroic intrusions in this study may suppose to be asthenosphere upheaving as anisolated hot wave in the presence of mantle fluid, resulting in basaltic magma intruded into thecontinental crust as a diapiric intrusion. Therefore, uplifting of faulting-block and extensionaldeformation could take place in the shallow part of the continental crust while vertical amassing andaccretion of magmatic materials in the deep part of the continental crust. These special processes couldsupposed to be a special background of continental dynamics for this large-scale epithermalmetaliogenic domain, such as Au

  20. Functional barriers: Properties and evaluation

    NARCIS (Netherlands)

    Feigenbaum, A.; Dole, P.; Aucejo, S.; Dainelli, D.; Cruz Garcia, C. de la; Hankemeier, T.; N'Gono, Y.; Papaspyrides, C.D.; Paseiro, P.; Pastorelli, S.; Pavlidou, S.; Pennarun, P.Y.; Saillard, P.; Vidal, L.; Vitrac, O.; Voulzatis, Y.

    2005-01-01

    Functional barriers are multilayer structures deemed to prevent migration of some chemicals released by food-contact materials into food. In the area of plastics packaging, different migration behaviours of mono- and multilayer structures are assessed in terms of lag time and of their influence of t

  1. Barrier/Cu contact resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Reid, J.S.; Nicolet, M.A. [California Inst. of Tech., Pasadena, CA (United States); Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y. [Cornell Univ., Ithaca, NY (United States); Smith, P.M. [Sandia National Labs., Albuquerque, NM (United States)

    1995-10-17

    The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

  2. Planar doped barrier subharmonic mixers

    Science.gov (United States)

    Lee, T. H.; East, J. R.; Haddad, G. I.

    1992-01-01

    The Planar Doped Barrier (PDB) diode is a device consisting of a p(+) doping spike between two intrinsic layers and n(+) ohmic contacts. This device has the advantages of controllable barrier height, diode capacitance and forward to reverse current ratio. A symmetrically designed PDB has an anti-symmetric current vs. voltage characteristic and is ideal for use as millimeter wave subharmonic mixers. We have fabricated such devices with barrier heights of 0.3, 0.5 and 0.7 volts from GaAs and InGaAs using a multijunction honeycomb structure with junction diameters between one and ten microns. Initial RF measurements are encouraging. The 0.7 volt barrier height 4 micron GaAs devices were tested as subharmonic mixers at 202 GHz with an IF frequency of 1 GHz and had 18 dB of conversion loss. The estimated mismatch loss was 7 dB and was due to higher diode capacitance. The LO frequency was 100.5 GHz and the pump power was 8 mW.

  3. FX barriers with smile dynamics

    NARCIS (Netherlands)

    Baker, Glyn; Beneder, Reimer; Zilber, Alex

    2004-01-01

    Our mandate in this work has been to isolate the features of smile consistent models that are most relevant to the pricing of barrier options. We consider the two classical approaches of stochastic and (parametric) local volatility. Although neither has been particularly successful in practice their

  4. Plastic Schottky barrier solar cells

    Science.gov (United States)

    Waldrop, James R.; Cohen, Marshall J.

    1984-01-24

    A photovoltaic cell structure is fabricated from an active medium including an undoped, intrinsically p-type organic semiconductor comprising polyacetylene. When a film of such material is in rectifying contact with a magnesium electrode, a Schottky-barrier junction is obtained within the body of the cell structure. Also, a gold overlayer passivates the magnesium layer on the undoped polyacetylene film.

  5. Rapid ascent and emplacement of basaltic lava during the 2005-06 eruption of the East Pacific Rise at ca. 9°51‧N as inferred from CO2 contents

    Science.gov (United States)

    Gardner, J. E.; Jackson, B. A.; Gonnermann, H.; Soule, S. A.

    2016-11-01

    Eruption rates at the mid-ocean ridges (MORs) are believed to strongly control the morphology and length of lava flows emplaced along the ridge axis, and thus the structure and porosity of the upper oceanic crust. Eruption rate also represents one of the few tools to gain insight into the driving pressures within sub-ridge magmatic systems. As eruption rate is inferred to vary systematically along the global mid-ocean ridge system, understanding of how to assess eruption rate in submarine systems and how it maps to observable features of the ridge axis would provide a powerful tool to understand Earth's largest magmatic system. Eruption rates at MORs are poorly constrained, however, because of a lack of direct observations, preventing the duration of an eruption to be quantified. This study uses decompression experiments of MORB samples and numerical modeling of CO2 degassing to reconstruct the timescales for magma ascent and lava emplacement during the 2005-06 eruption of the East Pacific Rise at ca. 9°51‧N. Samples collected from the lava flow are all supersaturated in dissolved CO2 contents, but CO2 decreases with distance from the vent, presumably as a consequence of progressive CO2 diffusion into growing bubbles. Samples collected at the vent contain ∼105 vesicles per cm3. Pieces of these samples were experimentally heated to 1225 °C at high pressure and then decompressed at controlled rates. Results, plus those from numerical modeling of diffusive bubble growth, indicate that magma rose from the axial magma chamber to the seafloor in ≤1 h and at a rate of ≥2-3 km h-1. Our modeling, as validated by experimental decompression of MORB samples with ∼106 vesicles cm-3, also suggests that CO2 degassed from the melt within ∼10-100 min as the vesicular lava traveled ∼1.7 km along the seafloor, implying a volumetric flow rate on order of 103-4 m3 s-1. Given an ascent rate of ≥0.2 m s-1, the width of a rectangular dike feeding the lava would have been

  6. Overexpanded viscous supersonic jet interacting with a unilateral barrier

    Science.gov (United States)

    Dobrynin, B. M.; Maslennikov, V. G.; Sakharov, V. A.; Serova, E. V.

    1986-07-01

    The interaction of a two-dimensional supersonic jet with a unilateral barrier parallel to the flow symmetry plane was studied to account for effects due to gas viscosity and backgound-gas ejection from the region into which the jet expands. In the present experiments, the incident shock wave was reflected at the end of a shock tube equipped with a nozzle. The jet emerged into a pressure chamber 6 cu m in volume and the environmental pressure ratio of the flow in the quasi-stationary phase remained constant. The light source was an OGM-20 laser operating in the giant-pulse mode. Due to background-gas ejection, the gas density in the vicinity of the barrier is much less than on the unconfined side of the jet. The resulting flow is characterized by two distinct environmental pressure ratios: the flow is underexpanded near the barrier, while on the other side it is overexpanded.

  7. Experimental study of fire barriers preventing vertical fire spread in ETISs

    Directory of Open Access Journals (Sweden)

    Xin Huang

    2013-11-01

    Full Text Available In recent years, the external thermal insulation system (ETIS has been applied increasingly in a large amount of buildings for energy conservation purpose. However, the increase use of combustible insulation materials in the ETIS has raised serious fire safety problems. Fires involving this type of ETIS have caused severe damage and loss. In order to improve its fire safety, fire barriers were suggested to be installed. This paper introduces fire experiments that have been done to study the effects of fire barriers on preventing vertical fire spread along the ETIS. The experiments were performed according to BS 8414-1:2002 “Fire performance of external cladding systems – Part 1: Test method for non-loadbearing external cladding systems applied to the face of the building”. The test facility consists of a 9 m high wall. The fire sources were wood cribs with a fire size of 3 ± 0.5 MW. The insulation materials were expanded polystyrene foam (EPS. The fire barrier was a horizontal strip of rockwool with a width of 300 mm. Thermocouples were used to measure temperatures outside and inside the ETIS. A series of experiments with different fire scenarios were done: no fire barrier, two fire barriers and three fire barriers at different heights. Test results were compared. The results show that the ETIS using EPS without fire barriers almost burned out, while the ETIS with fire barriers performed well in preventing fire spread. The temperatures above the fire barrier were much lower than those below the fire barrier, and most of the insulation materials above the top fire barrier stayed in place.

  8. Research on the application of active sound barriers for the transformer noise abatement

    Directory of Open Access Journals (Sweden)

    Hu Sheng

    2016-01-01

    Full Text Available Sound barriers are a type of measure most commonly used in the noise abatement of transformers. In the noise abatement project of substations, the design of sound barriers is restrained by the portal frames which are used to hold up outgoing lines from the main transformers, which impacts the noise reduction effect. If active sound barriers are utilized in these places, the noise diffraction of sound barriers can be effectively reduced. At a 110kV Substation, an experiment using a 15-channel active sound barrier has been carried out. The result of the experiment shows that the mean noise reduction value (MNRV of the noise measuring points at the substation boundary are 1.5 dB (A. The effect of the active noise control system is impacted by the layout of the active noise control system, the acoustic environment on site and the spectral characteristic of the target area.

  9. Barriers to Banking - Towards an Inclusive Banking Environment in South Africa.

    Science.gov (United States)

    Martinson, Estelle; Martinson, Johannes

    2016-01-01

    A recent study in South Africa on the barriers to banking which involved customers in three disability groups namely mobility, hearing and vision has highlighted that currently banking in South Africa is not accessible. Customers with a disability are unable to independently use banking services across a wide range of channels. Exclusion from something as fundamental as managing their own financial affairs raise serious human rights concerns and requires committed action from decision-makers to address this. The fact that solutions to all of the identified barriers have been successfully implemented in banks in other parts of the world for many years emphasize that this is not a technical challenge. While some solutions require complex or expensive changes such as removing physical access barriers and ensuring that digital channels meet internationally accepted standards of accessibility, there are many simple and low-cost solutions which can be implemented immediately and would make a world of difference to these customers and their experience of banking. One key barrier which emerged in all the focus groups and surveys is attitudinal barriers - staff who are unwilling to assist, impatient, interact with the customer's assistant instead of directly with them and lack basic skills on how to interact with someone who has a disability. A comprehensive framework of banking was used to identify a wide range of barriers. The barriers were classified as attitudinal, barriers to physical access, digital access barriers, barriers to information, communication barriers and some generic concerns such as safe evacuation during emergencies and alternative authentication. Both the barriers and the solutions where ranked by participants. From a theoretical perspective, the benefit of a customer-centric approach to understanding these barriers and the innovation potential of a Universal Design approach is affirmed by this study.

  10. YMP Engineered Barrier Systems Scaled Ventilation Testing

    Energy Technology Data Exchange (ETDEWEB)

    S.D. Dunn; B. Lowry; B. Walsh; J.D. Mar; C. Howard; R. Johnston; T. Williams

    2002-11-22

    Yucca Mountain, approximately 100 miles northwest of Las Vegas, Nevada, has been selected as the site for the nation's first geologic repository for high level nuclear waste. The Yucca Mountain Project (YMP) is currently developing the design for the underground facilities. Ventilation is a key component of the design as a way to maintain the desired thermal conditions in the emplacement drifts prior to closure. As a means of determining the effects of continuous ventilation on heat removal from the emplacement drifts two series of scaled ventilation tests have been performed. Both test series were performed in the DOE/North Las Vegas Atlas facility. The tests provided scaled (nominally 25% of the full scale emplacement drift design) thermal and flow process data that will be used to validate YMP heat and mass transport codes. The Phase I Ventilation Test series evaluated the ability of ambient ventilation air to remove energy under varying flow and input power conditions. The Phase II Ventilation Test series evaluated the ability of pre-conditioned ventilation air to remove energy under varying flow, input temperature and moisture content, and simulated waste package input power conditions. Twenty-two distinct ventilation tests were run.

  11. Growth of plutons by incremental emplacement of sheets in crystal-rich host: Evidence from Miocene intrusions of the Colorado River region, Nevada, USA

    Science.gov (United States)

    Miller, C.F.; Furbish, D.J.; Walker, B.A.; Claiborne, L.L.; Koteas, G.C.; Bleick, H.A.; Miller, J.S.

    2011-01-01

    Growing evidence supports the notion that plutons are constructed incrementally, commonly over long periods of time, yet field evidence for the multiple injections that seem to be required is commonly sparse or absent. Timescales of up to several million years, among other arguments, indicate that the dominant volume does not remain largely molten, yet if growing plutons are constructed from rapidly solidifying increments it is unlikely that intrusive contacts would escape notice. A model wherein magma increments are emplaced into melt-bearing but crystal-rich host, rather than either solid or crystal-poor material, provides a plausible explanation for this apparent conundrum. A partially solidified intrusion undoubtedly comprises zones with contrasting melt fraction and therefore strength. Depending on whether these zones behave elastically or ductilely in response to dike emplacement, intruding magma may spread to form sheets by either of two mechanisms. If the melt-bearing host is elastic on the relevant timescale, magma spreads rather than continuing to propagate upward, where it encounters a zone of higher rigidity (higher crystal fraction). Similarly, if the dike at first ascends through rigid, melt-poor material and then encounters a zone that is weak enough (poor enough in crystals) to respond ductilely, the ascending material will also spread because the dike tip ceases to propagate as in rigid material. We propose that ascending magma is thus in essence trapped, by either mechanism, within relatively crystal-poor zones. Contacts will commonly be obscure from the start because the contrast between intruding material (crystal-poorer magma) and host (crystal-richer material) is subtle, and they may be obscured even further by subsequent destabilization of the crystal-melt framework. Field evidence and zircon zoning stratigraphy in plutons of the Colorado River region of southern Nevada support the hypothesis that emplacement of magma replenishments into a

  12. Emplacement kinematics of nepheline syenites from the Terrane Boundary Shear Zone of the Eastern Ghats Mobile Belt, west of Khariar, NW Orissa: Evidence from meso- and microstructures

    Indian Academy of Sciences (India)

    T K Biswal; Harish Ahuja; Himansu Sekhar Sahu

    2004-12-01

    Nepheline syenite plutons emplaced within the Terrane Boundary Shear Zone of the Eastern Ghats Mobile Belt west of Khariar in northwestern Orissa are marked by a well-developed magmatic fabric including magmatic foliation, mineral lineations, folds and S-C fabrics. The minerals in the plutons, namely microcline, orthoclase, albite, nepheline, hornblende, biotite and aegirine show, by and large, well-developed crystal faces and lack undulose extinction and dynamic recrystallization, suggesting a magmatic origin. The magmatic fabric of the plutons is concordant with a solid-state strain fabric of the surrounding mylonites that developed due to noncoaxial strain along the Terrane Boundary Shear Zone during thrusting of the Eastern Ghats Mobile Belt over the Bastar Craton. However, a small fraction of the minerals, more commonly from the periphery of the plutons, is overprinted by a solid state strain fabric similar to that of the host rock. This fabric is manifested by discrete shear fractures, along which the feldspars are deformed into ribbons, have undergone dynamic recrystallization and show undulose extinction and myrmekitic growth. The shear fractures and the magmatic foliations are mutually parallel to the C-fabric of the host mylonites. Coexistence of concordant solid state strain fabric and magmatic fabric has been interpreted as a transitional feature from magmatic state to subsolidus deformation of the plutons, while the nepheline syenite magma was solidifying from a crystal-melt mush state under a noncoaxial strain. This suggests the emplacement of the plutons synkinematic to thrusting along the Terrane Boundary Shear Zone. The isotopic data by earlier workers suggest emplacement of nepheline syenite at 1500 + 3/− 4Ma, lending support for thrusting of the mobile belt over the craton around that time.

  13. Magma Emplacement and the 3D Geometry of Igneous Bodies in Rift Basins: Insights from the Bornu Basin, Onshore NE Nigeria

    Science.gov (United States)

    Suleiman, Adamu; Jackson, Christopher; Magee, Craig; Fraser, Alastair

    2016-04-01

    Recent studies of regional unconformities in the circum-South Atlantic tectonic plates have linked unconformity age to the timing of changes in the azimuth of oceanic fracture zones, caused by plate interactions during opening of the South Atlantic. This observation is significant, proposing that a plate boundary geodynamic processes are transmitted into and expressed in plate interiors. However, it is not yet clear if and how other geologic events, such as intra-plate magmatism, may be linked to changes in the oceanic fracture azimuthal geometry. Here we use 2D and 3D seismic reflection, geochemical, borehole datasets and outcrop observations from the Bornu Basin, one of several intra-continental rift basins located in NE Nigeria to constrain the 3D geometry of igneous bodies and magmatic emplacement processes. This allows us to link South Atlantic plate boundary geodynamics and magmatism in the surrounding continental rift basins. Seismic attributes, reflection intensity, relative acoustic impedance, were used to identify and map igneous intrusions. Saucer-shaped sills are the most common type of intrusion, although en-echelon sills, up to 1.4 km in length, were also identified. The 3D geometry of the sills reveals the detailed structural components like inner sill, inclined sheets and outer sill. A mapped bifurcating network of the sills suggests magma emplacement process through upward and outward propagation. Seismic-stratigraphic observations indicate that igneous activity occurred in the Early Cretaceous, Late Cretaceous and Paleogene corresponding to the timing of major azimuth changes observed in the Kane Oceanic fracture zone in the South Atlantic Ocean. Overall, our study, suggests a possible influence of plate boundary geodynamics on intra-plate magmatism as reflected in the link between the time of changes in the azimuth of oceanic fracture zones and magmatic emplacement observed in the tectono-stratigraphy of the intra-continental rift basins.

  14. Pluton emplacement in a releasing bend in a transpressive regime: the arrozal granite in the Paraíba do Sul shear belt, Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Alexis R. Nummer

    2007-06-01

    Full Text Available The Arrozal Granite, situated in the southwestern region of the State of Rio de Janeiro, has a granitic to granodioritic composition. It contains a strong mylonitic foliation along its border, passing gradually to a well-developed magmatic foliation towards its center. Structural analysis indicates that the Arrozal Granite was emplaced along the Além-Paraíba Shear Zone in a dextral transpressive tectonic regime. A regional shift of the trend along this shear zone from NE-SW to E-W, observed in the area, is interpreted to be casually related to the creation of space for the emplacement of the granite. Our data indicate that releasing bends may have played an important role for space generation during the emplacement of the Arrozal Granite and other plutons.O Granito Arrozal ocorre na porção sudoeste do Estado do Rio de Janeiro e associa-se à Zona de Cisalhamento de Além-Paraíba. Possui composição granítica a granodiorítica eexibe predomínio de estruturas magmáticas na parte central, e estruturas de alto strain (miloníticas nas bordas. Os dados estruturais sugerem colocação em segmentos extensionais(releasing bends associados a uma tectônica transcorrentedestral, sob regime transpressivo. A forte mudança do trend estrutural desta zona de cisalhamento na região, passando de NE-SW para próximo de E-W, criou condições para geração de espaços que favoreceram a colocação do Granito Arrozal, além de outros granitos associados à referida zona.

  15. Pre-waste-emplacement ground-water travel time sensitivity and uncertainty analyses for Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, P.G.

    1993-01-01

    Yucca Mountain, Nevada is a potential site for a high-level radioactive-waste repository. Uncertainty and sensitivity analyses were performed to estimate critical factors in the performance of the site with respect to a criterion in terms of pre-waste-emplacement ground-water travel time. The degree of failure in the analytical model to meet the criterion is sensitive to the estimate of fracture porosity in the upper welded unit of the problem domain. Fracture porosity is derived from a number of more fundamental measurements including fracture frequency, fracture orientation, and the moisture-retention characteristic inferred for the fracture domain.

  16. Patient advocacy: barriers and facilitators

    Directory of Open Access Journals (Sweden)

    Nikravesh Mansoure

    2006-03-01

    Full Text Available Abstract Background During the two recent decades, advocacy has been a topic of much debate in the nursing profession. Although advocacy has embraced a crucial role for nurses, its extent is often limited in practice. While a variety of studies have been generated all over the world, barriers and facilitators in the patient advocacy have not been completely identified. This article presents the findings of a study exploring the barriers and facilitators influencing the role of advocacy among Iranian nurses. Method This study was conducted by grounded theory method. Participants were 24 Iranian registered nurses working in a large university hospital in Tehran, Iran. Semi-structured interviews were used for data collection. All interviews were transcribed verbatim and simultaneously Constant comparative analysis was used according to the Strauss and Corbin method. Results Through data analysis, several main themes emerged to describe the factors that hindered or facilitated patient advocacy. Nurses in this study identified powerlessness, lack of support, law, code of ethics and motivation, limited communication, physicians leading, risk of advocacy, royalty to peers, and insufficient time to interact with patients and families as barriers to advocacy. As for factors that facilitated nurses to act as a patient advocate, it was found that the nature of nurse-patient relationship, recognizing patients' needs, nurses' responsibility, physician as a colleague, and nurses' knowledge and skills could be influential in adopting the advocacy role. Conclusion Participants believed that in this context taking an advocacy role is difficult for nurses due to the barriers mentioned. Therefore, they make decisions and act as a patient's advocate in any situation concerning patient needs and status of barriers and facilitators. In most cases, they can not act at an optimal level; instead they accept only what they can do, which we called 'limited advocacy' in

  17. Quantum mechanical streamlines. I - Square potential barrier

    Science.gov (United States)

    Hirschfelder, J. O.; Christoph, A. C.; Palke, W. E.

    1974-01-01

    Exact numerical calculations are made for scattering of quantum mechanical particles hitting a square two-dimensional potential barrier (an exact analog of the Goos-Haenchen optical experiments). Quantum mechanical streamlines are plotted and found to be smooth and continuous, to have continuous first derivatives even through the classical forbidden region, and to form quantized vortices around each of the nodal points. A comparison is made between the present numerical calculations and the stationary wave approximation, and good agreement is found between both the Goos-Haenchen shifts and the reflection coefficients. The time-independent Schroedinger equation for real wavefunctions is reduced to solving a nonlinear first-order partial differential equation, leading to a generalization of the Prager-Hirschfelder perturbation scheme. Implications of the hydrodynamical formulation of quantum mechanics are discussed, and cases are cited where quantum and classical mechanical motions are identical.

  18. Dielectric barrier discharges applied for optical spectrometry

    Science.gov (United States)

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, J.; Franzke, J.

    2016-09-01

    The present review reflects the importance of dielectric barrier discharges for optical spectrometric detection in analytical chemistry. In contrast to usual discharges with a direct current the electrodes are separated by at least one dielectric barrier. There are two main features of the dielectric barrier discharges: they can serve as dissociation and excitation devices as well as ionization sources, respectively. This article portrays various application fields of dielectric barrier discharges in analytical chemistry used for elemental and molecular detection with optical spectrometry.

  19. A Plagioclase Ultraphyric Basalt group in the Neogene flood basalt piles of eastern Iceland: Volcanic architecture and mode of emplacement

    Science.gov (United States)

    Oskarsson, B. V.; Riishuus, M. S.

    2013-12-01

    3D photogrammetry in conjunction with ground mapping was applied in order to assess the architecture of a Plagioclase Ultraphyric Basalt (PUB) group in eastern Iceland, namely the Grænavatn group. The ~10 Myr old group is exposed in steep glacially carved fjords and can be traced over 60 km along strike. Two feeder dikes have been found and show that the group erupted along the trend of the dike swarm associated with the Breiddalur central volcano. The group has 9--14 flows where thickest, and thins to about 3--4 flows up-dip to the east within the distance of 15-20 km from the source. We have estimated the volume of the group to exceed 40 km3. The flows have mixed architecture of simple and compound morphology. The flow lobes have thicknesses from 1--24 m and many reach lengths over 1000 m. The surface morphology varies from rubbly to scoriaceous, but is dominantly of pahoehoe style. The internal structure of the lava flows is well preserved and the flows display abundant vesicle cylinders. The modal percentage of An-rich plagioclase macrocrysts varies from 25--50 % and they are in the range of 5--30 mm. The aspect ratio of the group and the nature of the flows indicate fissure-fed eruptions. A thick flow found at the base of the group in various locations seems to record the largest eruption episode in the formation of the group. This phase is also the most abundant in macrocryst. An asymmetric buildup is seen in one location and may have characterized the general buildup of the group. The general morphology of the lava flows suggests low viscous behavior, at odds with the high crystal content. Petrographic observations and mineral chemistry shows that the plagioclase macrocrysts are very calcic (An80-85) and in disequilibrium with the groundmass and plagioclases therein (An50-70). Thus the apparent lava rheology and emplacement of the PUBs was likely achieved due to fast ascent of the magma through the crust and transfer of heat from the primitive macrocrysts

  20. The geology, geochemistry and emplacement of the Cretaceous—Tertiary ophiolitic Nicoya Complex of the Osa Peninsula, southern Costa Rica

    Science.gov (United States)

    Berrangé, J. P.; Thorpe, R. S.

    1988-04-01

    -S-trending transforms. The Cocos plate was subsequently split into two blocks separated by the Costa Rica Fracture Zone that extends northeastwards from the western end of the Colón Ridge to Costa Rica, which it divides into two distinctive volcanotectonic domains. To the north of the Costa Rica Fracture Zone, the Cocos plate is moving northeastwards and being consumed by the Middle America subduction zone, whereas the southern block is under the influence of the Colón spreading ridge with a N-S-oriented main stress axis. The N-S-trending Panama Fracture Zone can be extrapolated northwards via three submarine canyons on the continental slope to merge into a braided system of curved NW-trending coast-parallel wrench faults on which predominantly dextral strike-slip movement has produced pull-apart and tipped wedge basins with adjacent uplifted mini-horsts dating back to the Middle Pliocene. Therefore, although the Nicoya Complex of the Osa Peninsula was originally emplaced by accretion and thrusting related to pre-Oligocene plate movement, it owes its present-day exposure to post-Late Miocene wrench fault tectonics, with superimposed isostatic uplift.

  1. Intrusive rocks of the Holden and Lucerne quadrangles, Washington; the relation of depth zones, composition, textures, and emplacement of plutons

    Science.gov (United States)

    Cater, Fred W.

    1982-01-01

    serpentine. These occur either as included irregular masses in later intrusives or as tectonically emplaced lenses in metamorphic rocks. Also of uncertain age but probably much younger, perhaps as young as Eocene, are larger masses of hornblendite and hornblende periodotite that grade into hornblende gabbro. These are exposed on the surface and in the underground workings of the Holden mine. Oldest of the granitoid intrusives are the narrow, nearly concordant Dumbell Mountain plutons, having a radiometric age of about 220 m.y. They consist of gneissic hornblende-quartz diorite and quartz diorite gneiss. Most contacts consist of lit-par-lit zones, but some are gradational or more rarely sharp. The plutons are typically catazonal. Closely resembling the Dumbell Mountain plutons in outcrop appearance, but differing considerably in composition, are the Bearcat Ridge plutons. These consist of gneissic quartz diorite and granodiorite. The Bearcat Ridge plutons are not in contact with older dated plutons, but because their textural and structural characteristics so closely resemble those of the Dumbell Mountain plutons, they are considered to be the same age. Their composition, however, is suggestive of a much younger age. Cutting the Dumbell Mountain plutons is the Leroy Creek pluton, consisting of gneissic biotite-quartz diorite and trondjhemite. The gneissic foliation in the Leroy Creek is characterized by a strong and pervasive swirling. Cutting both the Dumbell Mountain and Leroy Creek plutons are the almost dikelike Seven-fingered Jack plutons. These range in composition from gabbro to quartz diorite; associated with them are contact complexes of highly varied rocks characterized by gabbro and coarse-grained hornblendite. Most of the rocks are gneissic, but some are massive and structureless. Radiometric ages by various methods range from 100 to 193 m.y. Dikes, sills, small stocks, and irregular clots of leucocratic quartz diorite and granodiorite are abundant in t

  2. Scattering of Ultracold Atoms from an Oscillating Barrier

    Science.gov (United States)

    Pyle, Andrew; Fancher, Charles; Ivory, Megan; Das, Kunal; Byrd, Tommy; Mitchell, Kevin; Delos, John; Aubin, Seth

    2016-05-01

    We present progress on an experiment to study 1D quantum mechanical scattering by an amplitude-modulated barrier. The barrier oscillating at frequency ω imparts or subtracts kinetic energy in discrete amounts from the scattered atoms. Simulations confirm that the atomic energy spectrum resembles a comb with a tooth spacing of ℏω . We present an atom chip-based system to study the scattering dynamics with Bose-Einstein condensates (BEC). A BEC is released from an optical dipole trap, while a modulated magnetic field gradient controls the vertical motion of the BEC as it travels towards a focused laser beam that serves as the barrier. Detection is carried out with a time of flight technique to resolve discrete atomic sidebands. This is a first step towards implementing a pump with atoms based on two such barriers modulated out of phase with one another. Ballistic quantum pumping was originally proposed for ballistic electron transport in nanowires, but has proven difficult to implement. The atomic approach is a route around the bottleneck in solid state systems, as optical superlattice experiments have recently confirmed. Work supported by W&M.

  3. Barrier Buckets and Transient Beam Loading in the SPS

    CERN Document Server

    Bohl, T; Garoby, R; Linnecar, Trevor Paul R; Shaposhnikova, Elena; Tückmantel, Joachim

    2003-01-01

    Using long bunches held in place by barrier buckets to overcome the limitations associated with peak density in high intensity bunched beams could be a promising scheme for increasing the luminosity of LHC. In the SPS at CERN an initial barrier bucket machine development(MD) study was done in 1999 to check the capabilities of 200 MHz thick barriers generated by the travelling wave system. A second experiment took place on 5th of August 2003 to examine high intensity effects. In this experiment a flat and stable long bunch of @ 3 µs bunch length was obtained and kept for more than 80 minutes without developing a significant line density modulation. However, strong beam loading effects were observed during the injection process, causing a coherent, non-negligible energy transfer from the beam to the RF cavities, and significant fraction of the injected beam was lost to a coasting beam background. The beam intensity that could be confined in between the barriers suffered emittance increase and was not high enou...

  4. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  5. Barriers to Mammography among Inadequately Screened Women

    Science.gov (United States)

    Stoll, Carolyn R. T.; Roberts, Summer; Cheng, Meng-Ru; Crayton, Eloise V.; Jackson, Sherrill; Politi, Mary C.

    2015-01-01

    Mammography use has increased over the past 20 years, yet more than 30% of women remain inadequately screened. Structural barriers can deter individuals from screening, however, cognitive, emotional, and communication barriers may also prevent mammography use. This study sought to identify the impact of number and type of barriers on mammography…

  6. Design of the Muong Chuoi Barrier

    NARCIS (Netherlands)

    Van Vliegen, K.; Van Oorschot, N.; Meinen, N.; Van Dijk, S.; Reimert, Z.

    2013-01-01

    Ho Chi Minh City has to deal with severe flooding in the rainy season. To prevent the city from this flooding, MARD set up plan 1547. The main idea of the plan is to build a ring dike around HCMC in combination with several movable tidal barriers. One of these barriers is the Muong Chuoi Barrier. I

  7. Market barriers to welfare product innovations

    NARCIS (Netherlands)

    Binnekamp, M.H.A.; Ingenbleek, P.T.M.

    2006-01-01

    New products that are based on higher animal welfare standards encounter several barriers on the road to market acceptance. The authors focus on the Dutch poultry sector and distinguish between retailer and consumer barriers. Retailer barriers include the powerful position of retailers, the price co

  8. Overcome barriers to career success

    Energy Technology Data Exchange (ETDEWEB)

    Raudsepp, E.

    1983-04-01

    A test is given to determine if an engineer suffers from one of the three barriers to technical success: fear of success, fear of failure, or perfectionism. As in most such tests, the middle way is best. Successful engineers know that perfection cannot be attained, that they don't have time to worry about failure or success, and that by aiming and perservering in doing things well, success can be achieved.

  9. Wet Work and Barrier Function.

    Science.gov (United States)

    Fartasch, Manigé

    2016-01-01

    Wet work defined as unprotected exposure to humid environments/water; high frequencies of hand washing procedures or prolonged glove occlusion is believed to cause irritant contact dermatitis in a variety of occupations. This review considers the recent studies on wet-work exposure and focuses on its influence on barrier function. There are different methods to study the effect of wet work on barrier function. On the one hand, occupational cohorts at risk can be monitored prospectively by skin bioengineering technology and clinical visual scoring systems; on the other hand, experimental test procedures with defined application of water, occlusion and detergents are performed in healthy volunteers. Both epidemiological studies and the results of experimental procedures are compared and discussed. A variety of epidemiological studies analyze occupational cohorts at risk. The measurement of transepidermal water loss, an indicator of the integrity of the epidermal barrier, and clinical inspection of the skin have shown that especially the frequencies of hand washing and water contact/contact to aqueous mixtures seem to be the main factors for the occurrence of barrier alterations. On the other hand, in a single cross-sectional study, prolonged glove wearing (e.g. occlusion for 6 h per shift in clean-room workers) without exposure to additional hazardous substances seemed not to affect the skin negatively. But regarding the effect of occlusion, there is experimental evidence that previously occluded skin challenged with sodium lauryl sulfate leads to an increased susceptibility to the irritant with an aggravation of the irritant reaction. These findings might have relevance for the real-life situation in so far as after occupational glove wearing, the skin is more susceptible to potential hazards to the skin even during leisure hours.

  10. Removing Barriers to Interdisciplinary Research

    CERN Document Server

    Jacobs, Naomi

    2010-01-01

    A significant amount of high-impact contemporary scientific research occurs where biology, computer science, engineering and chemistry converge. Although programmes have been put in place to support such work, the complex dynamics of interdisciplinarity are still poorly understood. In this paper we interrogate the nature of interdisciplinary research and how we might measure its "success", identify potential barriers to its implementation, and suggest possible mechanisms for removing these impediments.

  11. Flexible pile thermal barrier insulator

    Science.gov (United States)

    Anderson, G. E.; Fell, D. M.; Tesinsky, J. S. (Inventor)

    1978-01-01

    A flexible pile thermal barrier insulator included a plurality of upstanding pile yarns. A generally planar backing section supported the upstanding pile yarns. The backing section included a plurality of filler yarns forming a mesh in a first direction. A plurality of warp yarns were looped around said filler yarns and pile yarns in the backing section and formed a mesh in a second direction. A binder prevented separation of the yarns in the backing section.

  12. Lake Borgne Surge Barrier Study

    Science.gov (United States)

    2010-09-01

    Savant , and Darla C. McVan September 2010 Approved for public release; distribution is unlimited. ERDC/CHL TR-10-10 September 2010 Lake...Borgne Surge Barrier Study S. Keith Martin, Gaurav Savant , and Darla C. McVan Coastal and Hydraulics Laboratory U.S. Army Engineer Research and...conducted by Keith Martin, Dr. Gaurav Savant , and Darla C. McVan. This work was conducted at the Coastal and Hydraulics Laboratory (CHL) of the

  13. Barriers to Mental Health Treatment: Results from the WHO World Mental Health (WMH) Surveys

    Science.gov (United States)

    Andrade, L. H.; Alonso, J.; Mneimneh, Z.; Wells, J. E.; Al-Hamzawi, A.; Borges, G.; Bromet, E.; Bruffaerts, R.; de Girolamo, G.; de Graaf, R.; Florescu, S.; Gureje, O.; Hinkov, H. R.; Hu, C.; Huang, Y.; Hwang, I.; Jin, R.; Karam, E. G.; Kovess-Masfety, V.; Levinson, D.; Matschinger, H.; O’Neill, S.; Posada-Villa, J.; Sagar, R.; Sampson, N. A.; Sasu, C.; Stein, D.; Takeshima, T.; Viana, M. C.; Xavier, M.; Kessler, R. C.

    2014-01-01

    Background To examine barriers to initiation and continuation of mental health treatment among individuals with common mental disorders. Methods Data are from the WHO World Mental Health (WMH) Surveys. Representative household samples were interviewed face-to-face in 24 countries. Reasons to initiate and continue treatment were examined in a subsample (n= 63,678) and analyzed at different levels of clinical severity. Results Among those with a DSM-IV disorder in the past twelve months, low perceived need was the most common reason for not initiating treatment and more common among moderate and mild than severe cases. Women and younger people with disorders were more likely to recognize a need for treatment. Desire to handle the problem on one’s own was the most common barrier among respondents with a disorder who perceived a need for treatment (63.8%). Attitudinal barriers were much more important than structural barriers both to initiating and continuing treatment. However, attitudinal barriers dominated for mild-moderate cases and structural barriers for severe cases. Perceived ineffectiveness of treatment was the most commonly reported reason for treatment dropout (39.3%) followed by negative experiences with treatment providers (26.9% of respondents with severe disorders). Conclusions Low perceived need and attitudinal barriers are the major barriers to seeking and staying in treatment among individuals with common mental disorders worldwide. Apart from targeting structural barriers, mainly in countries with poor resources, increasing population mental health literacy is an important endeavor worldwide. PMID:23931656

  14. Barriers and facilitators of sports in Dutch Paralympic athletes: An explorative study.

    Science.gov (United States)

    Jaarsma, E A; Geertzen, J H B; de Jong, R; Dijkstra, P U; Dekker, R

    2014-10-01

    The purpose of this study was to gain insight in barriers and facilitators of sports in paralympic athletes. An online questionnaire was distributed through the Netherlands Olympic Committee and National Sports Confederation to determine personal and environmental barriers and facilitators of sports participation. The International Classification of Functioning, Disability and Health model and theory of planned behavior were used to respectively categorize the results in environmental and personal factors, and attitude, subjective norm and perceived behavioral control. Seventy-six Dutch Paralympic athletes completed the questionnaire (51% response rate). Barriers and facilitators experienced by ambulant and wheelchair athletes were compared. Most frequently mentioned personal barrier was dependency of others (22%), while most frequently mentioned environmental barrier was lack of sports facilities (30%). Wheelchair athletes mentioned more barriers (median = 3, interquartile range: 0.5-6), than ambulant athletes (median = 1.0,interquartile range:0.0-3.0, P = 0.023). One-third of the athletes did not experience any barriers. Most frequently mentioned personal facilitators to initiate sports participation were fun (78%), health (61%), and competition (53%). Most frequently mentioned environmental facilitator was social support (40%). This study indicated that barriers of sport were mostly environmental, while facilitators were usually personal factors. Attitude and subjective norm were considered the most important components for intention to participation in sports. The facilitators outweighed the barriers and kept the athletes being active in sports.

  15. The complex influences of back-barrier deposition, substrate slope and underlying stratigraphy in barrier island response to sea-level rise: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, U.S.A.

    Science.gov (United States)

    Brenner, Owen T.; Moore, Laura J.; Murray, A. Brad

    2015-10-01

    To understand the relative importance of back barrier environment, substrate slope and underlying stratigraphy in determining barrier island response to RSLR (relative sea-level rise), we use a morphological-behavior model (GEOMBEST) to conduct a series of sensitivity experiments, based on late-Holocene hindcast simulations of an island in the U.S. mid-Atlantic Bight (Metompkin Island, VA) having both salt marsh and lagoonal back-barrier environments, and we draw comparisons between these results and future simulations (2000-2100 AD) of island response to RSLR. Sensitivity analyses indicate that, as a whole, the island is highly sensitive to factors that reduce overall sand availability (i.e., high sand-loss rates and substrates containing little sand). Results also indicate that for all predicted future RSLR scenarios tested, islands having high substrate sand proportions (if allowed to migrate freely) will likely remain subaerial for centuries because of sufficient substrate sand supply and elevation to assist in keeping islands above sea level. Simulation results also lead to basic insights regarding the interactions among substrate slope, back-barrier deposition and island migration rates. In contrast to previous studies, which suggest that changes in substrate slope directly affect the island migration trajectory, we find that-in the presence of back-barrier deposition-the connection between substrate slope and island behavior is modulated (i.e., variability in migration rates is dampened) by changes in back-barrier width. These interactions-which tend to produce changes in shoreface sand content-lead to a negative feedback when the back-barrier deposit contains less sand than the underlying layer, resulting in a stable back-barrier width. Alternatively, a positive feedback arises when the back-barrier deposit contains more sand than the underlying layer, resulting in either back-barrier disappearance or perpetual widening.

  16. Long-term climate change assessment study plan for the Hanford Site Permanent Isolation Barrier Development Program. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, K.L. [Westinghouse Hanford Co., Richland, WA (United States); Chatters, J.C. [Pacific Northwest Lab., Richland, WA (United States); Waugh, W.J. [Chem-Nuclear Geotech, Inc., Grand Junction, CO (United States)

    1993-05-01

    The Hanford Site Permanent Isolation Barrier Development Program (Barrier Development Program) was organized to develop the technology needed to provide an in-place disposal capability for low-level nuclear waste for the US Department of Energy at the Hanford Site in south-central Washington. The goal of the Barrier Development Program is to provide defensible evidence that final barrier design(s) will adequately control water infiltration, plant and animal intrusion, and wind and water erosion for a minimum of 1,000 yr; to isolate wastes from the accessible environment; and to use markers to warn inadvertent human intruders. Evidence for barrier performance will be obtained by conducting laboratory experiments, field tests, computer modeling, and other studies that establish confidence in the barrier`s ability to meet its 1,000-yr design life.

  17. Recruitment barriers in a randomized controlled trial from the physicians' perspective – A postal survey

    Directory of Open Access Journals (Sweden)

    Karrer Werner

    2009-03-01

    Full Text Available Abstract Background The feasibility of randomized trials often depends on successful patient recruitment. Although numerous recruitment barriers have been identified it is unclear which of them complicate recruitment most. Also, most surveys have focused on the patients' perspective of recruitment barriers whereas the perspective of recruiting physicians has received less attention. Therefore, our aim was to conduct a postal survey among recruiting physicians of a multi-center trial to weigh barriers according to their impact on recruitment. Methods We identified any potential recruitment barriers from the literature and from our own experience with a multi-center trial of respiratory rehabilitation in patients with chronic obstructive pulmonary disease. We developed and pilot-tested a self-administered questionnaire where recruiting physicians were asked to express their agreement with statements about recruitment barriers on a Likert-type scale from 1 (full agreement with statement = very substantial recruitment barrier to 7 (no agreement with statement = no recruitment barrier. Results 38 of 55 recruiting physicians returned questionnaires (69% response rate, of which 35 could be analyzed (64% useable response rate. Recruiting physicians reported that "time constraints" (median agreement of 3, interquartile range 2–5 had the most negative impact on recruitment followed by "difficulties including identified eligible patients" (median agreement of 5, IQR 3–6. Other barriers such as "trial design barriers", "lack of access to treatment", "individual barriers of recruiting physicians" or "insufficient training of recruiting physicians" were perceived to have little or no impact on patient recruitment. Conclusion Physicians perceived time constraints as the most relevant recruitment barrier in a randomized trial. To overcome recruitment barriers interventions, that are affordable for both industry- and investigator-driven trials, need to be

  18. Influence of the geometry of protective barriers on the propagation of shock waves

    Science.gov (United States)

    Sochet, I.; Eveillard, S.; Vinçont, J. Y.; Piserchia, P. F.; Rocourt, X.

    2016-04-01

    The protection of industrial facilities, classified as hazardous, against accidental or intentional explosions represents a major challenge for the prevention of personal injury and property damage, which also involves social and economic issues. We consider here the use of physical barriers against the effects of these explosions, which include the pressure wave, the projection of fragments and the thermal flash. This approach can be recommended for the control of major industrial risks, but no specific instructions are available for its implementation. The influence of a protective barrier against a detonation-type explosion is studied in small-scale experiments. The effects of overpressure are examined over the entire path of the shock wave across the barrier and in the downstream zone to be protected. Two series of barrier structures are studied. The first series (A) of experiments investigates two types of barrier geometry with dimensions based on NATO recommendations. These recommendations stipulate that the barrier should be 2 m higher than the charge height, the thickness at the crest should be more than 0.5 m, while its length should be equal to twice the protected structure length and the bank slope should be equivalent to the angle of repose of the soil. The second series (B) of experiments investigates the influence of geometrical parameters of the barrier (thickness at the crest and inclination angles of the front and rear faces) on its protective effects. This project leads to an advance in our understanding of the physical phenomena involved in the propagation of blast waves resulting from an external explosion, in the area around a protective physical barrier. The study focuses on the dimensioning of protective barriers against overpressure effects arising from detonation and shows the advantage of using a barrier with a vertical front or rear face.

  19. Influence of the geometry of protective barriers on the propagation of shock waves

    Science.gov (United States)

    Sochet, I.; Eveillard, S.; Vinçont, J. Y.; Piserchia, P. F.; Rocourt, X.

    2017-03-01

    The protection of industrial facilities, classified as hazardous, against accidental or intentional explosions represents a major challenge for the prevention of personal injury and property damage, which also involves social and economic issues. We consider here the use of physical barriers against the effects of these explosions, which include the pressure wave, the projection of fragments and the thermal flash. This approach can be recommended for the control of major industrial risks, but no specific instructions are available for its implementation. The influence of a protective barrier against a detonation-type explosion is studied in small-scale experiments. The effects of overpressure are examined over the entire path of the shock wave across the barrier and in the downstream zone to be protected. Two series of barrier structures are studied. The first series (A) of experiments investigates two types of barrier geometry with dimensions based on NATO recommendations. These recommendations stipulate that the barrier should be 2 m higher than the charge height, the thickness at the crest should be more than 0.5 m, while its length should be equal to twice the protected structure length and the bank slope should be equivalent to the angle of repose of the soil. The second series (B) of experiments investigates the influence of geometrical parameters of the barrier (thickness at the crest and inclination angles of the front and rear faces) on its protective effects. This project leads to an advance in our understanding of the physical phenomena involved in the propagation of blast waves resulting from an external explosion, in the area around a protective physical barrier. The study focuses on the dimensioning of protective barriers against overpressure effects arising from detonation and shows the advantage of using a barrier with a vertical front or rear face.

  20. Paving the seafloor: Volcanic emplacement processes during the 2005-2006 eruptions at the fast spreading East Pacific Rise, 9°50‧N

    Science.gov (United States)

    Fundis, A. T.; Soule, S. A.; Fornari, D. J.; Perfit, M. R.

    2010-08-01

    The 2005-2006 eruptions near 9°50'N at the East Pacific Rise (EPR) marked the first observed repeat eruption at a mid-ocean ridge and provided a unique opportunity to deduce the emplacement dynamics of submarine lava flows. Since these new flows were documented in April 2006, a total of 40 deep-towed imaging surveys have been conducted with the Woods Hole Oceanographic Institution's (WHOI) TowCam system. More than 60,000 digital color images and high-resolution bathymetric profiles of the 2005-2006 flows from the TowCam surveys were analyzed for lava flow morphology and for the presence of kipukas, collapse features, faults and fissures. We use these data to quantify the spatial distributions of lava flow surface morphologies and to investigate how they relate to the physical characteristics of the ridge crest, such as seafloor slope, and inferred dynamics of flow emplacement. We conclude that lava effusion rate was the dominant factor controlling the observed morphological variations in the 2005-2006 flows. We also show that effusion rates were higher than in previously studied eruptions at this site and varied systematically along the length of the eruptive fissure. This is the first well-documented study in which variations in seafloor lava morphology can be directly related to a well documented ridge-crest eruption where effusion rate varied significantly.

  1. Petrography and chemical evidence for multi-stage emplacement of western Buem volcanic rocks in the Dahomeyide orogenic belt, southeastern Ghana, West Africa

    Science.gov (United States)

    Nude, Prosper M.; Kwayisi, Daniel; Taki, Naa A.; Kutu, Jacob M.; Anani, Chris Y.; Banoeng-Yakubo, Bruce; Asiedu, Daniel K.

    2015-12-01

    The volcanic rocks of the Buem Structural Unit in the Dahomeyide orogenic belt of southeastern Ghana, constitute a unique assemblage among the monocyclic sedimentary formations of this structural unit. Representative volcanic rock samples were collected from the Asukawkaw, Bowiri-Odumase and Nkonya areas which form a roughly north-south trend. The volcanic rocks comprise spherulitic, amygdaloidal, vesicular, phyric and aphyric varieties. Whole rock geochemistry shows that these volcanic rocks exhibit both alkaline and subalkaline characteristics. The alkaline varieties are relatively enriched in REE and incompatible trace element concentrations, similar to OIB; the subalkaline varieties show E-MORB and N-MORB REE and incompatible element characteristics. The rocks have low La/Nb (<1), low K/Nb (<450) and high Nb/U (averagely 47.3) values, suggesting no significant effect of crustal contamination. The key characteristics of these volcanic rocks are the distinct petrography and geochemistry, shown from the three separate localities, which may suggest source fractionation at different depths or modes of emplacement. The association of volcanic rocks of OIB, E-MORB and N-MORB affinities, with no significant crustal contamination, may suggest mantle derived magma that may have been related to rifting event and eventual emplacement at the eastern passive margin of the West African Craton.

  2. Textural analysis of particles from El Zaguán debris avalanche deposit, Nevado de Toluca volcano, Mexico: Evidence of flow behavior during emplacement

    Science.gov (United States)

    Caballero, Lizeth; Capra, Lucia

    2011-02-01

    El Zaguán deposit originated at 28,000 yrs. B.P. from the flank collapse of Nevado de Toluca, a dacitic stratovolcano of the Transmexican Volcanic Belt. Scanning Electron Microprobe analyses (SEM) were performed on some particles from this deposit to observe microtextures produced during transport and emplacement of the debris avalanche flow. Particles from 2ϕ (250 μm), 0ϕ (1 mm) and - 2ϕ (4 mm) granulometric classes were randomly selected at different outcrops, and their surface textures were described. The observed textures are divided in two groups, Basal and Upper textures, each one indicating different clast interactions. Basal textures are observed predominantly in the lower part of the deposit and consist of parallel ridges, parallel grooves, scratches and lips. Upper textures are mainly present in the upper part of the deposit and consisted of fractures, percussion marks, and broken or grinded crystals. These characteristics, coupled with field observations such as the presence of clastic dikes and deformed lacustrine mega-blocks, indicate that the basal part of the debris avalanche was moving in a partially liquefied state. By contrast, the particles in the upper part were able to move freely, interacting by collision. These microscopic textures are in agreement with previously described emplacement behaviors in debris avalanches of volcanic origin, suggesting a stratified flow dominated by different transport and depositional mechanisms depending upon flow depth and possible fluid content at their base.

  3. Sem Analysis of particles from the 28, 000 B.P El Zaguan debris avalanche deposit, Nevado de Toluca volcano, Central Mexico: evidences of flow behavior during emplacement

    Science.gov (United States)

    Caballero, L.; Capra, L.

    2008-12-01

    The Zaguan deposit originated at 28, 000 yr. B.P from the flank collapse of the Nevado de Toluca volcano, a dacitic stratovolcano of the Transmexican Volcanic Belt. A Scanning Electron Microprobe analysis (SEM) was made to some clasts of this deposit to observe microtextures produced during transport and emplacement of the debris avalanche flow. Particles from 2, 0 and -2 Φ granulometric classes were randomly selected and their surface textures were described. The textures observed were divided in two groups, collision and shear structures indicating different clast interaction. Shear textures were observed predominantly on the basal part of the deposit and consisted of parallel ridges, parallel grooves, scratches and lips. Collision textures were mainly present in the upper part of the deposit and consisted of fractures, percussion marks, and broken or grinded crystals. These characteristics, coupled with field observation, like the presence of clast dikes and deformed lacustrine megaclasts, indicate that the basal part of the debris avalanche was moving in a partially liquefied state, were particles were not able to move freely because of the confinement exerted by the upper part of the flow, so shear stresses dominated. On the contrary, the particles in the upper part were able to move freely so the principal mechanism of interaction between particles was collision. These microscopic textures are in agreement with previously described behavior of emplacement of debris avalanches of volcanic origin, that suggest a stratified flow dominated by different transport and depositional mechanism depending on flow depth and possible fluid content at their base.

  4. Simulation of ventilation efficiency, and pre-closure temperatures in emplacement drifts at Yucca Mountain, Nevada, using Monte Carlo and composite thermal-pulse methods

    Science.gov (United States)

    Case, J.B.; Buesch, D.C.

    2004-01-01

    Predictions of waste canister and repository driftwall temperatures as functions of space and time are important to evaluate pre-closure performance of the proposed repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. Variations in the lithostratigraphic features in densely welded and crystallized rocks of the 12.8-million-year-old Topopah Spring Tuff, especially the porosity resulting from lithophysal cavities, affect thermal properties. A simulated emplacement drift is based on projecting lithophysal cavity porosity values 50 to 800 m from the Enhanced Characterization of the Repository Block cross drift. Lithophysal cavity porosity varies from 0.00 to 0.05 cm3/cm3 in the middle nonlithophysal zone and from 0.03 to 0.28 cm3/cm3 in the lower lithophysal zone. A ventilation model and computer program titled "Monte Carlo Simulation of Ventilation" (MCSIMVENT), which is based on a composite thermal-pulse calculation, simulates statistical variability and uncertainty of rock-mass thermal properties and ventilation performance along a simulated emplacement drift for a pre-closure period of 50 years. Although ventilation efficiency is relatively insensitive to thermal properties, variations in lithophysal porosity along the drift can result in a range of peak driftwall temperatures can range from 40 to 85??C for the preclosure period. Copyright ?? 2004 by ASME.

  5. Fast emplacement of extensive pahoehoe flow-fields: the case of the 1736 flows from Montaña de las Nueces, Lanzarote

    Science.gov (United States)

    Solana, M. C.; Kilburn, C. R. J.; Rodriguez Badiola, E.; Aparicio, A.

    2004-04-01

    The 1730-36 Timanfaya eruption on Lanzarote, in the Canary Islands, is the second largest historical effusion on record. During its final stages, in 1736, the eruption produced the Montaña de las Nueces flow-field, consisting of sheets of pahoehoe lava that, within 4 weeks, had covered 32 km 2 and reached a maximum length of almost 21 km. The tholeiitic lavas have pahoehoe surface features, but internal structures that are normally associated with massive aa flows, suggesting that their fronts advanced as single units rather than as a collection of budding pahoehoe tongues. Volume conservation and a simple model of crustal failure suggest that the main flows advanced at about 0.02 ms -1 over the prevailing slopes of ˜1°. The rates of advance are (1) consistent with emplacement near the transition from pahoehoe to aa, and (2) about an order of magnitude greater than would have been expected by analogy with Hawaiian pahoehoe flow-fields of similar dimensions. Surface texture and morphology, therefore, is an insufficient guide for constraining the rate and style of pahoehoe emplacement, and a flow's internal structure must be established before its characteristics are used to infer eruption conditions and potential hazard.

  6. Emplacement age of the Tahe granite and its constraints on the tectonic nature of the Ergun block in the northern part of the Da Hinggan Range

    Institute of Scientific and Technical Information of China (English)

    GE Wenchun; WU Fuyuan; ZHOU Changyong; Abdel Rahman A. A.

    2005-01-01

    Large-scale granitic plutons are exposed in the Ergun block in the northern part of the Da Hinggan Range, but their emplacement age and petrogenesis remain unknown. Of these plutons, the Tahe pluton is composed mainly of porphyritic syenogranite and monzogranite, with minor hornblende alkali feldspar granite and gabbro, which have affinities to post-orogenic granitoids. Laser-ablation Inductively Coupled Plasma Mass-spectroscope (LA-ICP-MS) analysis shows that the major rock types of the Tahe pluton formed at 494-480 Ma ago, indicating its emplacement in the Early Paleozoic. It is concluded, therefore, that the collision between the Ergun and the Xing'an blocks ended in Early Paleozoic. Considering the geochronological data of the plutons in the adjacent areas, the Early Paleozoic evolutionary history of the Ergun block is similar to the central Mongolia and the Tuvino blocks in Mongolia, and the Ergun block should be a part of the accretionary continental margin in the southern Siberian Craton.

  7. Diffraction of sound by nearly rigid barriers

    Science.gov (United States)

    Hadden, W. J., Jr.; Pierce, A. D.

    1976-01-01

    The diffraction of sound by barriers with surfaces of large, but finite, acoustic impedance was analyzed. Idealized source-barrier-receiver configurations in which the barriers may be considered as semi-infinite wedges are discussed. Particular attention is given to situations in which the source and receiver are at large distances from the tip of the wedge. The expression for the acoustic pressure in this limiting case is compared with the results of Pierce's analysis of diffraction by a rigid wedge. An expression for the insertion loss of a finite impedance barrier is compared with insertion loss formulas which are used extensively in selecting or designing barriers for noise control.

  8. Mathematical modeling of complex noise barriers

    Energy Technology Data Exchange (ETDEWEB)

    Hayek, S.I.

    1982-01-01

    Mathematical modeling of the noise reduction efficiency of highway noise barriers depends on the shape and absorptivity of the barrier, the influence of the impedance of the ground under the receiver, the atmospheric conditions as well as traffic details. The mathematical model for a barrier's noise reduction requires the knowledge of point-to-point acoustic diffraction models. In many instances, the shape of the barrier is simple; such as thin wall (edge), sharp wedge, and cylindrically topped berms. However, new designs of more efficient barriers have been investigated recently.

  9. Persisting Barriers to Employment for Recently Housed Adults with Mental Illness Who Were Homeless.

    Science.gov (United States)

    Poremski, Daniel; Woodhall-Melnik, Julia; Lemieux, Ashley J; Stergiopoulos, Vicky

    2016-02-01

    Adults with mental illness who are homeless experience multiple barriers to employment, contributing to difficulties securing and maintaining housing. Housing First programs provide quick, low-barrier access to housing and support services for this population, but their success in improving employment outcomes has been limited. Supported employment interventions may augment Housing First programs and address barriers to employment for homeless adults with mental illness. The present paper presents data from qualitative interviews to shed light on the persisting barriers to employment among people formerly homeless. Once housed, barriers to employment persisted, including the following: (1) worries about disclosing sensitive information, (2) fluctuating motivation, (3) continued substance use, and (4) fears about re-experiencing homelessness-related trauma. Nevertheless, participants reported that their experiences of homelessness helped them develop interpersonal strength and resilience. Discussing barriers with an employment specialist helps participants develop strategies to overcome them, but employment specialists must be sensitive to specific homelessness-related experiences that may not be immediately evident. Supported housing was insufficient to help people return to employment. Supported employment may help people return to work by addressing persisting barriers.

  10. Midwives unable to overcome language barriers in prenatal care

    Directory of Open Access Journals (Sweden)

    Mirjam P. Fransen

    2012-09-01

    Full Text Available

    Background: the present study aims to explore to what extent midwives experience barriers in providing information about prenatal screening for Down syndrome to women from diverse ethnic backgrounds, and to assess their competences to overcome these barriers.

    Methods: midwives from 24 Dutch midwifery practices in Rotterdam completed a structured webbased questionnaire (n=57. Data were obtained on perceived ethnic-related differences and barriers in providing information on prenatal screening, preparedness to provide cultural competent care, and the use of translated materials and professional translators. A group interview was conducted to further explore the results emerging from the questionnaire (n=23.

    Results: almost all midwives (95% experienced barriers in informing women from non-Western ethnic backgrounds about prenatal screening. Midwives especially felt incompetent to provide information to pregnant women that hardly speak and understand Dutch. In total 58% of the midwives reported that they never used translated information materials and 88% never used professional interpreters in providing information on prenatal screening. The main reasons for this underutilization were unawareness of the availability of translated materials and unfamiliarity with the use of professional interpreters.

    Conclusions: although language barriers were reported to be the main difficulty in providing cultural competent care to patients from diverse ethnic backgrounds, only a minority of the midwives used translated materials or professional interpreters. In order to enable all pregnant women to make an informed decision whether or not to participate in prenatal screening, midwives’ competences to address language barriers should be increased.

  11. A study on the quantitative evaluation of skin barrier function

    Science.gov (United States)

    Maruyama, Tomomi; Kabetani, Yasuhiro; Kido, Michiko; Yamada, Kenji; Oikaze, Hirotoshi; Takechi, Yohei; Furuta, Tomotaka; Ishii, Shoichi; Katayama, Haruna; Jeong, Hieyong; Ohno, Yuko

    2015-03-01

    We propose a quantitative evaluation method of skin barrier function using Optical Coherence Microscopy system (OCM system) with coherency of near-infrared light. There are a lot of skin problems such as itching, irritation and so on. It has been recognized skin problems are caused by impairment of skin barrier function, which prevents damage from various external stimuli and loss of water. To evaluate skin barrier function, it is a common strategy that they observe skin surface and ask patients about their skin condition. The methods are subjective judgements and they are influenced by difference of experience of persons. Furthermore, microscopy has been used to observe inner structure of the skin in detail, and in vitro measurements like microscopy requires tissue sampling. On the other hand, it is necessary to assess objectively skin barrier function by quantitative evaluation method. In addition, non-invasive and nondestructive measuring method and examination changes over time are needed. Therefore, in vivo measurements are crucial for evaluating skin barrier function. In this study, we evaluate changes of stratum corneum structure which is important for evaluating skin barrier function by comparing water-penetrated skin with normal skin using a system with coherency of near-infrared light. Proposed method can obtain in vivo 3D images of inner structure of body tissue, which is non-invasive and non-destructive measuring method. We formulate changes of skin ultrastructure after water penetration. Finally, we evaluate the limit of performance of the OCM system in this work in order to discuss how to improve the OCM system.

  12. Dielectric barrier discharges in analytical chemistry.

    Science.gov (United States)

    Meyer, C; Müller, S; Gurevich, E L; Franzke, J

    2011-06-21

    The present review reflects the importance of dielectric barrier discharges in analytical chemistry. Special about this discharge is-and in contrast to usual discharges with direct current-that the plasma is separated from one or two electrodes by a dielectric barrier. This gives rise to two main features of the dielectric barrier discharges; it can serve as dissociation and excitation device and as ionization mechanism, respectively. The article portrays the various application fields for dielectric barrier discharges in analytical chemistry, for example the use for elemental detection with optical spectrometry or as ionization source for mass spectrometry. Besides the introduction of different kinds of dielectric barrier discharges used for analytical chemistry from the literature, a clear and concise classification of dielectric barrier discharges into capacitively coupled discharges is provided followed by an overview about the characteristics of a dielectric barrier discharge concerning discharge properties and the ignition mechanism.

  13. Avoiding barriers in control of mowing robot

    Institute of Scientific and Technical Information of China (English)

    QIU Bai-jing; QIAN Guo-hong; XIANG Zhong-ping; LI Zuo-peng

    2006-01-01

    Due to complicated barriers,it is difficult to track the path of the mowing robot and to avoid barriers.In order to solve the problem,a method based on distance-measuring sensors and fuzzy control inputs was proposed.Its track was composed of beelines and was easy to tail.The fuzzy control inputs were based on the front barrier distance and the difference between the left and right barrier distance measured by ultrasonic sensors;the output was the direction angle.The infrared sensors around the robot improved its safety in avoiding barriers.The result of the method was feasible,agile,and stable.The distance between the robot and the barriers could be changed by altering the inputs and outputs of fuzzy control and the length of the beelines.The disposed sensors can fulfill the need of the robot in avoiding barriers.

  14. Fundamental Investigations Regarding Barrier Properties of Grafted PVOH Layers

    Directory of Open Access Journals (Sweden)

    Markus Schmid

    2012-01-01

    Full Text Available The current work focuses on fundamental investigations regarding the barrier properties of grafted PVOH layers produced by the Transfer Method. The layers (or papers used for the different experiments were produced and grafted during the course of this work. Papers with different types of PVOH (different Mowiol types were produced by coating. Experiments using different parameters (temperature, reaction duration, and concentration were performed using the Transfer Method. Contact angle measurements and Cobb60 measurements were carried out on the grafted and untreated PVOH layers. Furthermore, the water vapour transmission rate of the PVOH layers was determined. The results of this work showed that the method of chromatogeny or chromatogenic chemistry improves the water vapour barrier properties of grafted PVOH layers enormously.

  15. The blood-brain barrier: an engineering perspective

    OpenAIRE

    Wong, Andrew D.; Ye, Mao; Levy, Amanda F.; Rothstein, Jeffrey D.; Bergles, Dwight E.; Searson, Peter C.

    2013-01-01

    It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich's first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and this selective permeability remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of...

  16. Implementation of renewable energy technology - Opportunities and barriers. Summary of country studies

    Energy Technology Data Exchange (ETDEWEB)

    Painuly, J.P.; Fenhann, J.V.

    2002-07-01

    The project was launched to identify barriers to the implementation of renewable energy technologies (RETs) and explore measures to overcome the identified barriers. National institutions in Egypt, Ghana and Zimbabwe carried out the country studies based on the basic methodological framework provided by the UNEP Centre. The objectives of the project included strengthening institutional capacity for analysis and implementation of RET projects in the participating countries and bring out experiences on RETs barriers and removal measures for dissemination so that others can benefit from the knowledge so gained. An important highlight of the studies was involvement of stake holders in the process of identification of barriers and measures to remove them. A preliminary identification of relevant RETs for their countries was done by the country teams in the initial stage of the project. After that, national workshops involving various stake holders were held between July and September 1999 to discuss the RETs and barriers to their implementation. Based on the discussions, a few important RETs were identified for more detailed study. PV systems for rural electrification, solar water heating systems and large-scale biogas system were identified and analysed for barriers in the Egypt country study. Economic, information and policy barriers were identified as major barriers for these technologies. Solar water pumps, biogas and small hydro were the focus of study in Ghana. In this case also, economic, information and policy barriers were found to be the important barriers for the selected technologies. In the case of Zimbabwe, focus was on identification of primary and secondary barriers to RETs dissemination. The primary barriers included lack of capacity to develop proposals, lack of information for policy making and framework for information dissemination. The study concluded that the secondary barriers as seen and experienced by the stake holders are due to primary

  17. Experimental testing of flexible barriers for containment of debris flows

    Science.gov (United States)

    DeNatale, Jay S.; Iverson, Richard M.; Major, Jon J.; LaHusen, Richard G.; Fliegel, Gregg L.; Duffy, John D.

    1999-01-01

    In June 1996, six experiments conducted at the U.S. Geological Survey Debris Flow Flume demonstrated that flexible, vertical barriers constructed of wire rope netting can stop small debris flows. All experimental debris flows consisted of water-saturated gravelly sand with less than two percent finer sediment by weight. All debris flows had volumes of about 10 cubic meters, masses of about 20 metre tons, and impact velocities of 5 to 9 meters per second. In four experiments, the debris flow impacted pristine, unreformed barriers of varying design; in the other two experiments, the debris flow impacted barriers already loaded with sediment from a previous flow. Differences in barrier design led to differences in barrier performance. Experiments were conducted with barriers constructed of square-mesh wire-rope netting with 30centimeter, 20centimeter, and 15 centimeter mesh openings as well as 30centimeter diameter interlocking steel rings. In all cases, sediment cascading downslope at the leading edge of the debris flows tended to spray through the nets. Nets fitted with finer-mesh chain link or chicken wire liners contained more sediment than did unlined nets, and a ring net fitted with a synthetic silt screen liner contained nearly 100 percent of the sediment. Irreversible net displacements of up to 2 meters and friction brake engagement on the support and anchor cables dissipated some of the impact energy. However, substantial forces developed in the steel support columns and the lateral and tie-back anchor cables attached to these columns. As predicted by elementary mechanics, the anchor cables experienced larger tensile forces when the support columns were hinged at the base rather than bolted rigidly to the foundation. Measured loads in the lateral anchor cables exceeded those in the tie-back anchor cables and the load cell capacity of 45 kilo-Newtons. Measurements also indicated that the peak loads in the tie- back anchors were highly transient and occurred at

  18. Subsurface Barrier Formation as a CO2 Leakage Mitigation Technology

    Science.gov (United States)

    Castaneda Herrera, C. A.; Stevens, G.; Haese, R. R.

    2015-12-01

    Long-term CO2 containment in a geological storage reservoir is a key criterion for successfully implementing carbon capture and storage (CCS), however, CO2 leakage through different pathways cannot be completely ruled out in some instances. In this study we investigate the conditions for reactive barrier formation as a technology to mitigate and remediate CO2 leakage. We propose to inject a liquid reagent consistent of an alkaline sodium-silicate solution on top of the storage caprock, which will lead to silica mineral precipitation when in contact with an acidic, CO2-enriched fluid. This reaction will create a barrier that seals the leakage by reducing the permeability. Preliminary modelling has shown that the density, viscosity and alkalinity of the reagent fluid are critical for a successful seal formation, whereas differences in formation water composition and in the rock mineral composition are less important. In order to study the reaction through experiments, different reagent solutions were prepared and characterised in terms of silica concentration, density, viscosity and buffer capacity. In a static, diffusion-controlled batch experiment we observed silica mineral precipitation in the outer layer of the piece of rock inhibiting further mixing of the two fluids and slowing down the initial reaction rate. Core-flood experiments will be carried out to simulate barrier formation under fluid flow conditions. Here, the sealing efficiency of the reaction will be continuously measured in terms of a change in permeability.

  19. Engineered barriers for radioactive waste confinement

    Directory of Open Access Journals (Sweden)

    Fernández, R.

    2011-09-01

    Full Text Available Nuclear power plants generate long-lived radioactive waste of high toxicity. The security assessment of repositories destined to definitive confinement of radioactive waste has been studied for several decades. Deep geological repositories are technically feasible and begin to be built by some pioneer countries. The scientific evaluation of interactions between the different engineered barriers is studied by laboratory experiments, natural analogues and modeling studies. The three methods are able to represent and validate the main geochemical processes that take place in the near field. This paper reviews the scientific and technical basis of the concept of geological disposal, with particular focus on the methods of study applied to the evaluation of geochemical stability of the bentonite barrier.

    Las centrales nucleares generan residuos radiactivos de elevada peligrosidad y permanencia en el tiempo. La evaluación de la seguridad de repositorios destinados al alojamiento definitivo de estos residuos lleva estudiándose desde hace varias décadas. El almacenamiento geológico es técnicamente factible y empieza ya a desarrollarse en países pioneros. La evaluación científica de las interacciones entre las distintas barreras de ingeniería se estudia mediante ensayos de laboratorio, análisis de análogos naturales y modelos teóricos. Las tres vías de estudio son capaces de representar y validar los principales procesos geoquímicos que tienen lugar en el campo cercano al repositorio. Este artículo revisa los fundamentos científicos y técnicos del concepto de almacenamiento geológico detallando, en particular, los métodos de estudio aplicados a la evaluación de la estabilidad geoquímica de la barrera de bentonita.

  20. Rethinking Social Barriers to Effective Adaptive Management

    Science.gov (United States)

    West, Simon; Schultz, Lisen; Bekessy, Sarah

    2016-09-01

    Adaptive management is an approach to environmental management based on learning-by-doing, where complexity, uncertainty, and incomplete knowledge are acknowledged and management actions are treated as experiments. However, while adaptive management has received significant uptake in theory, it remains elusively difficult to enact in practice. Proponents have blamed social barriers and have called for social science contributions. We address this gap by adopting a qualitative approach to explore the development of an ecological monitoring program within an adaptive management framework in a public land management organization in Australia. We ask what practices are used to enact the monitoring program and how do they shape learning? We elicit a rich narrative through extensive interviews with a key individual, and analyze the narrative using thematic analysis. We discuss our results in relation to the concept of `knowledge work' and Westley's 2002) framework for interpreting the strategies of adaptive managers—`managing through, in, out and up.' We find that enacting the program is conditioned by distinct and sometimes competing logics—scientific logics prioritizing experimentation and learning, public logics emphasizing accountability and legitimacy, and corporate logics demanding efficiency and effectiveness. In this context, implementing adaptive management entails practices of translation to negotiate tensions between objective and situated knowledge, external experts and organizational staff, and collegiate and hierarchical norms. Our contribution embraces the `doing' of learning-by-doing and marks a shift from conceptualizing the social as an external barrier to adaptive management to be removed to an approach that situates adaptive management as social knowledge practice.

  1. Tunneling without barriers with gravity

    CERN Document Server

    Kanno, Sugumi; Soda, Jiro

    2012-01-01

    We consider the vacuum decay of the flat Minkowski space to an anti-de Sitter space. We find a one-parameter family of potentials that allow exact, analytical instanton solutions describing tunneling without barriers in the presence of gravity. In the absence of gravity such instantons were found and discussed by Lee and Weinberg more than a quarter of a century ago. The bounce action is also analytically computed. We discuss possible implications of these new instantons to cosmology in the context of the string theory landscape.

  2. FIELD TEST INSTRUCTION 100-NR-2 OPERABLE UNIT DESIGN OPTIMIZATION STUDY FOR SEQUESTRATION OF SR-90 SATURATED ZONE APATITE PERMEABLE REACTIVE BARRIER EXTENSION

    Energy Technology Data Exchange (ETDEWEB)

    BOWLES NA

    2010-10-06

    The objective of this field test instruction is to provide technical guidance for aqueous injection emplacement of an extension apatite permeable reactive barrier (PRE) for the sequestration of strontium-90 (Sr-90) using a high concentration amendment formulation. These field activities will be conducted according to the guidelines established in DOE/RL-2010-29, 100-NR-2 Design Optimization Study, hereafter referred to as the DOS. The DOS supports the Federal Facility Agreement Consent Order (EPA et al., 1989), Milestone M-16-06-01, and 'Complete Construction of a Permeable Reactive Barrier at 100-N.' Injections of apatite precursor chemicals will occur at an equal distance intervals on each end of the existing PRE to extend the PRB from the existing 91 m (300 ft) to at least 274 m (900 ft). Field testing at the 100-N Area Apatite Treatability Test Site, as depicted on Figure 1, shows that the barrier is categorized by two general hydrologic conceptual models based on overall well capacity and contrast between the Hanford and Ringold hydraulic conductivities. The upstream portion of the original barrier, shown on Figure 1, is characterized by relatively low overall well specific capacity. This is estimated from well development data and a lower contrast in hydraulic conductivity between the Hanford formation and Ringold Formations. Comparison of test results from these two locations indicate that permeability contrast between the Hanford formation and Ringold Formation is significantly less over the upstream one-third of the barrier. The estimated hydraulic conductivity for the Hanford formation and Ringold Formation over the upstream portion of the barrier based on observations during emplacement of the existing 91 m (300 ft) PRB is approximately 12 and 10 m/day (39 and 32 ft/day), respectively (PNNL-17429). However, these estimates should be used as a rough guideline only, as significant variability in hydraulic conductivity is likely to be observed in

  3. Management of erectile dysfunction: barriers faced by general practitioners

    Institute of Scientific and Technical Information of China (English)

    Wah-YunLow; Chirk-JennNg; Ngiap-ChuanTan; Wan-YuenChoo; Hui-MengTan

    2004-01-01

    Aim: To explore the barriers faced by general practitioners (GPs) in the management of patients with erectile dysfunction (ED). Methods: This was a qualitative analysis of focus group discussions and in-depth interviews involving 28 Malaysian GPs. Results: GPs' perception of ED being not a serious condition was a major determinant of their prescribing practice. Doctor's age (younger), gender (female), short consultation time and lack of experience were cited as barriers. The GPs' prescribing habits were heavily influenced by the feedback from the first few patients under treatment, the uncertainty of etiology of ED without proper assessment and the profit margin with bulk purchase. Other barriers include Patients' coexisting medical conditions, older age, lower socio-economic status, unrealistic expectations and inappropriate use of the anti-impoteneet drugs. Cardiovascular side effects and cost were two most important drug barriers. Conclusion: The factors influencing the management of ED among the general practitioners were multiple and complex. An adequate understanding of how these factors (doctors, patientsand drugs) interact can assist in the formulation and implementation of strategies that encourage GPs to identify and manage ED patients.

  4. On the performance of capillary barriers as landfill cover

    Science.gov (United States)

    Kämpf, M.; Montenegro, H.

    Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

  5. On the performance of capillary barriers as landfill cover

    Directory of Open Access Journals (Sweden)

    M. Kämpf

    1997-01-01

    Full Text Available Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m. In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

  6. Effect of Geochemical and Physical Heterogeneity on the Hanford 100D Area In Situ Redox Manipulation Barrier Longevity

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, Jim E.; Vermeul, Vince R.; Fruchter, Jonathan S.; Williams, Mark D.; Phillips, Jerry L.; Devary, Brooks J.; Rockhold, Mark L.; Liu, Ying

    2005-11-30

    approximately 20 years, (with 5 mg/L dissolved oxygen and 2 ppm chromate) is reduced to 85 pore volumes (10 years) when the wide spread 60 ppm nitrate plume is included in the calculation. However, this reduction in barrier lifetime is not as great for high permeability channels, as there is insufficient time to reduce nitrate (and consume ferrous iron). If the cause of laterally discontinuous breakthrough of chromate along the ISRM barrier is due to oxic transport of chromate near the water table, additional dithionite treatment in these zones will not be effective. Treatment near the water table with a technology that emplaces considerable reductive capacity is needed, such as injectable zero valent iron.

  7. Effect of Geochemical and Physical Heterogeneity on the Hanford 100D Area In Situ Redox Manipulation Barrier Longevity

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, Jim E.; Fruchter, Jonathan S.; Phillips, Jerry L.; Rockhold, Mark L.; Vermeul, Vince R.; Williams, Mark D.; Devary, Brooks J.; Liu, Ying

    2005-12-22

    approximately 20 years, (with 5 mg/L dissolved oxygen and 2 ppm chromate) is reduced to 85 pore volumes (10 years) when the wide spread 60 ppm nitrate plume is included in the calculation. However, this reduction in barrier lifetime is not as great for high permeability channels, as there is insufficient time to reduce nitrate (and consume ferrous iron). If the cause of laterally discontinuous breakthrough of chromate along the ISRM barrier is due to oxic transport of chromate near the water table, additional dithionite treatment in these zones will not be effective. Treatment near the water table with a technology that emplaces considerable reductive capacity is needed, such as injectable zero valent iron.

  8. The mode of emplacement of Neogene flood basalts in Eastern Iceland: The plagioclase ultraphyric basalts in the Grænavatn group

    Science.gov (United States)

    V. Óskarsson, Birgir; B. Andersen, Christina; S. Riishuus, Morten; Sørensen, Erik Vest; Tegner, Christian

    2017-02-01

    Plagioclase ultraphyric basalt lava with high fraction of solids have a mode of emplacement that is poorly understood. In this study we conduct detailed mapping of a PUB group in eastern Iceland, namely the Grænavatn group, and assess the group architecture, flow morphology and internal structure with additional constraints from petrography, petrology and crystal size distribution, to derive information on emplacement dynamics of plagioclase ultraphyric basalts. We also derive information on the plumbing system of the group with reference to the source of the macrocysts. The group is exposed in steep glacially carved fjords and can be traced for more than 70 km along strike. The flows have mixed architecture of simple and compound flows. Individual flow lobes have thicknesses in the range of 1-24 m and many reach widths and lengths exceeding 1000 m. The flows vary from rubbly to slabby pahoehoe, but are predominantly of pahoehoe type. The aspect ratio of the group and the nature of the flows indicate fissure-fed eruptions. The plagioclase macrocrysts (5-30 mm) are An-rich, exhibit bimodal size distribution and the modal proportions within the group varies from 15-40%. Clinopyroxene macrocrysts are also present ranging from 1-6%. The lowermost flow is thickest and carries the greatest crystal cargo load. The morphology of the lava flows suggests low viscous behavior, at odds with the high crystal content. The very calcic plagioclase macrocrysts (An80-85) are in disequilibrium with the groundmass and plagioclase microlaths therein (An50-70), meaning that the crystal-laden magmas quickly ascended from deeper crustal levels to the surface. The flows with highest crystal content may have maintained high temperatures by heat exchange with the primitive macrocrysts in the flows and developed non-Newtonian behavior such as shear thinning. Such conditions would have enabled the flows to advance rapidly during episodes with high effusion rates forming the simple flows, and

  9. Westinghouse thermal barrier coatings development

    Energy Technology Data Exchange (ETDEWEB)

    Goedjen, J.G.; Wagner, G. [Westinghouse Electric Corp., Orlando, FL (United States)

    1995-10-01

    Westinghouse, in conjunction with the Department of Energy and Oak Ridge National Laboratory, has embarked upon a program for the development of advanced thermal barrier coatings for industrial gas turbines. Development of thermal barrier coatings (TBC`s) for industrial gas turbines has relied heavily on the transfer of technology from the aerospace industry. Significant differences in the time/temperature/stress duty cycles exist between these two coating applications. Coating systems which perform well in aerospace applications may not been optimized to meet power generation performance requirements. This program will focus on development of TBC`s to meet the specific needs of power generation applications. The program is directed at developing a state-of-the-art coating system with a minimum coating life of 25,000 hours at service temperatures required to meet increasing operating efficiency goals. Westinghouse has assembled a team of university and industry leaders to accomplish this goal. Westinghouse will coordinate the efforts of all program participants. Chromalloy Turbine Technologies, Inc. and Sermatech International, Inc. will be responsible for bond coat and TBC deposition technology. Praxair Specialty Powders, Inc. will be responsible for the fabrication of all bond coat and ceramic powders for the program. Southwest Research Institute will head the life prediction modelling effort; they will also be involved in coordinating nondestructive evaluation (NDE) efforts. Process modelling will be provided by the University of Arizona.

  10. Overcoming Barriers in Unhealthy Settings

    Directory of Open Access Journals (Sweden)

    Michael K. Lemke

    2016-03-01

    Full Text Available We investigated the phenomenon of sustained health-supportive behaviors among long-haul commercial truck drivers, who belong to an occupational segment with extreme health disparities. With a focus on setting-level factors, this study sought to discover ways in which individuals exhibit resiliency while immersed in endemically obesogenic environments, as well as understand setting-level barriers to engaging in health-supportive behaviors. Using a transcendental phenomenological research design, 12 long-haul truck drivers who met screening criteria were selected using purposeful maximum sampling. Seven broad themes were identified: access to health resources, barriers to health behaviors, recommended alternative settings, constituents of health behavior, motivation for health behaviors, attitude toward health behaviors, and trucking culture. We suggest applying ecological theories of health behavior and settings approaches to improve driver health. We also propose the Integrative and Dynamic Healthy Commercial Driving (IDHCD paradigm, grounded in complexity science, as a new theoretical framework for improving driver health outcomes.

  11. PWM Converter Power Density Barriers

    Science.gov (United States)

    Kolar, Johann W.; Drofenik, Uwe; Biela, Juergen; Heldwein, Marcelo; Ertl, Hans; Friedli, Thomas; Round, Simon

    Power density of power electronic converters has roughly doubled every 10 years since 1970. Behind this trajectory is the continuous advancement of power semiconductor devices, which has increased the converter switching frequencies by a factor of 10 every decade. However, today's cooling concepts and passive components are major barriers for a continuation of this trend. To identify such technological barriers, this paper investigates the volume of the cooling system and passive components as a function of the switching frequency for power electronic converters and determines the switching frequency that minimizes the total volume. A power density limit of 28kW/dm3 at 300kHz is calculated for an isolated DC-DC converter, 44kW/dm3 at 820kHz for a three-phase unity power factor PWM rectifier, and 26kW/dm3 at 21kHz for a sparse matrix converter. For single-phase AC-DC conversion a general limit of 35kW/dm3 results from the DC link capacitor. These power density limits highlight the need to broaden the scope of power electronics research to include cooling systems, high frequency electromagnetics, interconnection and packaging technology, and multi-domain modelling and simulation to ensure further advancement along the power density trajectory.

  12. Barriers to medical error reporting

    Directory of Open Access Journals (Sweden)

    Jalal Poorolajal

    2015-01-01

    Full Text Available Background: This study was conducted to explore the prevalence of medical error underreporting and associated barriers. Methods: This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan,Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Results: Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%, lack of proper reporting form (51.8%, lack of peer supporting a person who has committed an error (56.0%, and lack of personal attention to the importance of medical errors (62.9%. The rate of committing medical errors was higher in men (71.4%, age of 50-40 years (67.6%, less-experienced personnel (58.7%, educational level of MSc (87.5%, and staff of radiology department (88.9%. Conclusions: This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  13. A double barrier memristive device

    Science.gov (United States)

    Hansen, M.; Ziegler, M.; Kolberg, L.; Soni, R.; Dirkmann, S.; Mussenbrock, T.; Kohlstedt, H.

    2015-09-01

    We present a quantum mechanical memristive Nb/Al/Al2O3/NbxOy/Au device which consists of an ultra-thin memristive layer (NbxOy) sandwiched between an Al2O3 tunnel barrier and a Schottky-like contact. A highly uniform current distribution for the LRS (low resistance state) and HRS (high resistance state) for areas ranging between 70 μm2 and 2300 μm2 were obtained, which indicates a non-filamentary based resistive switching mechanism. In a detailed experimental and theoretical analysis we show evidence that resistive switching originates from oxygen diffusion and modifications of the local electronic interface states within the NbxOy layer, which influences the interface properties of the Au (Schottky) contact and of the Al2O3 tunneling barrier, respectively. The presented device might offer several benefits like an intrinsic current compliance, improved retention and no need for an electric forming procedure, which is especially attractive for possible applications in highly dense random access memories or neuromorphic mixed signal circuits.

  14. Overcoming Barriers to Skills Training in Borderline Personality Disorder: A Qualitative Interview Study.

    Directory of Open Access Journals (Sweden)

    Kirsten Barnicot

    Full Text Available Despite evidence suggesting that skills training is an important mechanism of change in dialectical behaviour therapy, little research exploring facilitators and barriers to this process has been conducted. The study aimed to explore clients' experiences of barriers to dialectical behaviour therapy skills training and how they felt they overcame these barriers, and to compare experiences between treatment completers and dropouts. In-depth qualitative interviews were conducted with 40 clients with borderline personality disorder who had attended a dialectical behaviour therapy programme. A thematic analysis of participants' reported experiences found that key barriers to learning the skills were anxiety during the skills groups and difficulty understanding the material. Key barriers to using the skills were overwhelming emotions which left participants feeling unable or unwilling to use them. Key ways in which participants reported overcoming barriers to skills training were by sustaining their commitment to attending therapy and practising the skills, personalising the way they used them, and practising them so often that they became an integral part of their behavioural repertoire. Participants also highlighted a number of key ways in which they were supported with their skills training by other skills group members, the group therapists, their individual therapist, friends and family. Treatment dropouts were more likely than completers to describe anxiety during the skills groups as a barrier to learning, and were less likely to report overcoming barriers to skills training via the key processes outlined above. The findings of this qualitative study require replication, but could be used to generate hypotheses for testing in further research on barriers to skills training, how these relate to dropout, and how they can be overcome. The paper outlines several such suggestions for further research.

  15. Overcoming Barriers to Skills Training in Borderline Personality Disorder: A Qualitative Interview Study.

    Science.gov (United States)

    Barnicot, Kirsten; Couldrey, Laura; Sandhu, Sima; Priebe, Stefan

    2015-01-01

    Despite evidence suggesting that skills training is an important mechanism of change in dialectical behaviour therapy, little research exploring facilitators and barriers to this process has been conducted. The study aimed to explore clients' experiences of barriers to dialectical behaviour therapy skills training and how they felt they overcame these barriers, and to compare experiences between treatment completers and dropouts. In-depth qualitative interviews were conducted with 40 clients with borderline personality disorder who had attended a dialectical behaviour therapy programme. A thematic analysis of participants' reported experiences found that key barriers to learning the skills were anxiety during the skills groups and difficulty understanding the material. Key barriers to using the skills were overwhelming emotions which left participants feeling unable or unwilling to use them. Key ways in which participants reported overcoming barriers to skills training were by sustaining their commitment to attending therapy and practising the skills, personalising the way they used them, and practising them so often that they became an integral part of their behavioural repertoire. Participants also highlighted a number of key ways in which they were supported with their skills training by other skills group members, the group therapists, their individual therapist, friends and family. Treatment dropouts were more likely than completers to describe anxiety during the skills groups as a barrier to learning, and were less likely to report overcoming barriers to skills training via the key processes outlined above. The findings of this qualitative study require replication, but could be used to generate hypotheses for testing in further research on barriers to skills training, how these relate to dropout, and how they can be overcome. The paper outlines several such suggestions for further research.

  16. Implementation of renewable energy technologies - Opportunities and barriers. Egypt country study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The project used case studies of renewable energy implementation projects to analyse the reasons for success or failure of specific projects or technologies. In particular the study aimed to identify possibilities for 'removing' the main barriers and thus 'promoting' increased implementation of (RETs), and to 'generalise' the experiences from the case studies and produce results that can be disseminated and utilized further in a planned second phase. The specific objectives for Egypt Country Study were: 1) To determine, on the basis of analysis of the past experience, the barriers against implementation of RETs in Egypt, and to identify the favourable conditions and actions required for such implementation. 2) To apply the knowledge gained and results of the analysis of past projects for a detailed analysis of barriers to a chosen set of potential RETs implementation projects with view to success. 3) To identify specific RET projects for implementation including necessary actions to overcome identified barriers. The case study revealed that; for Domestic Solar Water Heating (DSWH) the main barriers are; the economic barriers followed by the awareness / information barriers, then the Technical and Institution barriers. For the PV rural electrification, the most important barriers are; the economic and financial barriers, the awareness and information barriers then the technical barriers. For the large-scale biogas systems, the main barriers are the institution and capacity, economic, policy and awareness / information respectively. According to the project results the main actions that could be taken to overcome the barriers and make use of the available opportunities are: Economic / Financial: 1) Creation of new financial schemes for the RETs applications components and systems. 2) Reducing the taxes and duties for the components and / or materials needed for Renewable Energy (RE) systems. 3) More government-supported market incentives

  17. Relativistic Double Barrier Problem with Three Sub-Barrier Transmission Resonance Regions

    CERN Document Server

    Alhaidari, A D; Jellal, A

    2010-01-01

    We obtain exact scattering solutions of the Dirac equation in 1+1 dimensions for a double square barrier vector potential. The potential floor between the two barriers is higher than 2mc^2 whereas the top of the barriers is at least 2mc^2 above the floor. The relativistic version of the conventional double barrier transmission resonance is obtained for energies within + or - mc^2 from the height of the barriers. However, we also find two more (sub-barrier) transmission resonance regions below the conventional one. Both are located within the two Klein energy zones and characterized by resonances that are broader than the conventional ones.

  18. Modeling the impact of solid noise barriers on near road air quality

    Science.gov (United States)

    Venkatram, Akula; Isakov, Vlad; Deshmukh, Parikshit; Baldauf, Richard

    2016-09-01

    Studies based on field measurements, wind tunnel experiments, and controlled tracer gas releases indicate that solid, roadside noise barriers can lead to reductions in downwind near-road air pollutant concentrations. A tracer gas study showed that a solid barrier reduced pollutant concentrations as much as 80% next to the barrier relative to an open area under unstable meteorological conditions, which corresponds to typical daytime conditions when residents living or children going to school near roadways are most likely to be exposed to traffic emissions. The data from this tracer gas study and a wind tunnel simulation were used to develop a model to describe dispersion of traffic emissions near a highway in the presence of a solid noise barrier. The model is used to interpret real-world data collected during a field study conducted in a complex urban environment next to a large highway in Phoenix, Arizona, USA. We show that the analysis of the data with the model yields useful information on the emission factors and the mitigation impact of the barrier on near-road air quality. The estimated emission factors for the four species, ultrafine particles, CO, NO2, and black carbon, are consistent with data cited in the literature. The results suggest that the model accounted for reductions in pollutant concentrations from a 4.5 m high noise barrier, ranging from 40% next to the barrier to 10% at 300 m from the barrier.

  19. Comparison between two models of absorption of matter waves by a thin time-dependent barrier

    Science.gov (United States)

    Barbier, Maximilien; Beau, Mathieu; Goussev, Arseni

    2015-11-01

    We report a quantitative, analytical, and numerical comparison between two models of the interaction of a nonrelativistic quantum particle with a thin time-dependent absorbing barrier. The first model represents the barrier by a set of time-dependent discontinuous matching conditions, which are closely related to Kottler boundary conditions used in stationary-wave optics as a mathematical basis for Kirchhoff diffraction theory. The second model mimics the absorbing barrier with an off-diagonal δ potential with a time-dependent amplitude. We show that the two models of absorption agree in their predictions in a semiclassical regime, the regime readily accessible in modern experiments with ultracold atoms.

  20. Reflection and transmission of regular waves at a surface-pitching slotted barrier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The interactions between regular surface waves and a surface-pitching slotted barrier are investigated both analytically and experimentally.A quasi-linear theory is developed using the eigenfunction expansion method.The energy dissipation within the barriers is modeled by a quadratic friction factor, and an equivalent linear dissipation coefficient, which is depth-varying, wave-height dependent, is introduced to linearize the matching condition at the surface-pitching barrier.By comparing the theoretical results with laboratory experiments, it is shown that the present method can satisfactorily predict the variation of the reflection and transmission coefficients with wave height.

  1. Hydrothermal organic synthesis experiments

    Science.gov (United States)

    Shock, Everett L.

    1992-01-01

    Ways in which heat is useful in organic synthesis experiments are described, and experiments on the hydrothermal destruction and synthesis of organic compounds are discussed. It is pointed out that, if heat can overcome kinetic barriers to the formation of metastable states from reduced or oxidized starting materials, abiotic synthesis under hydrothermal conditions is a distinct possibility. However, carefully controlled experiments which replicate the descriptive variables of natural hydrothermal systems have not yet been conducted with the aim of testing the hypothesis of hydrothermal organic systems.

  2. Identification of Key Barriers in Workforce Development

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-03-31

    This report documents the identification of key barriers in the development of an adequate national security workforce as part of the National Security Preparedness Project, being performed under a Department of Energy/National Nuclear Security Administration grant. Many barriers exist that prevent the development of an adequate number of propertly trained national security personnel. Some barriers can be eliminated in a short-term manner, whereas others will involve a long-term strategy that takes into account public policy.

  3. From a long-lived upper-crustal magma chamber to rapid porphyry copper emplacement: Reading the geochemistry of zircon crystals at Bajo de la Alumbrera (NW Argentina)

    Science.gov (United States)

    Buret, Yannick; von Quadt, Albrecht; Heinrich, Christoph; Selby, David; Wälle, Markus; Peytcheva, Irena

    2016-09-01

    The formation of world class porphyry copper deposits reflect magmatic processes that take place in a deeper and much larger underlying magmatic system, which provides the source of porphyry magmas, as well as metal and sulphur-charged mineralising fluids. Reading the geochemical record of this large magmatic source region, as well as constraining the time-scales for creating a much smaller porphyry copper deposit, are critical in order to fully understand and quantify the processes that lead to metal concentration within these valuable mineral deposits. This study focuses on the Bajo de la Alumbrera porphyry copper deposit in Northwest Argentina. The deposit is centred on a dacitic porphyry intrusive stock that was mineralised by several pulses of porphyry magma emplacement and hydrothermal fluid injections. To constrain the duration of ore formation, we dated zircons from four porphyry intrusions, including pre-, syn- and post-mineralisation porphyries based on intersection relations between successive intrusion and vein generations, using high precision CA-ID-TIMS. Based on the youngest assemblages of zircon grains, which overlap within analytical error, all four intrusions were emplaced within 29 ka, which places an upper limit on the total duration of hydrothermal mineralisation. Re/Os dating of hydrothermal molybdenite fully overlaps with this high-precision age bracket. However, all four porphyries contain zircon antecrysts which record protracted zircon crystallisation during the ∼200 ka preceding the emplacement of the porphyries. Zircon trace element variations, Ti-in-zircon temperatures, and Hf isotopic compositions indicate that the four porphyry magmas record a common geochemical and thermal history, and that the four intrusions were derived from the same upper-crustal magma chamber. Trace element zoning within single zircon crystals confirms a fractional crystallisation trend dominated by titanite and apatite crystallisation. However, zircon

  4. Magma Emplacement and Mafic-Felsic Magma Hybridisation: Structural, Microstructural and Geochemical Evidences From the Pan-African Negash Pluton, Northern Ethiopia

    Science.gov (United States)

    ASRAT, A.; BARBEY, P.; GLEIZES, G.; LUDDEN, J.

    2002-05-01

    The Negash pluton (50 sq. km) consists of late Pan-African, high-K, calc-alkaline granitoids intruded into low-grade metavolcanics and metasediments. This almost circular massif consists of monzogranites, granodiorites, monzodiorites, monzogabbros, and hybrid quartz monzodiorites. The rocks are enriched in LIL-elements, depleted in HFS-elements, have fractionated REE patterns, low 87Sr/86Sri (0.702344 - 0.703553) and 143Nd/144Ndi (0.512031 - 0.512133) ratios, positive ɛ Nd values (3.46 to 5.40), and Pan-African model Nd ages (0.83 to 1.08 Ga). These data, along with single zircon U-Pb dating, show that the pluton was emplaced at 608 Ma from primitive source (underplated material or juvenile island arc crust) with contamination by the country rocks. The pluton shows widespread mafic-felsic magma interactions of two types: (i) homogeneous and heterogeneous hybrid monzodiorites at the northwestern part; and (ii) mingled interfaces at the diorite-granodiorite contact zones in the Eastern and Southeastern parts. Detailed structural (using the method of the anisotropy of magnetic susceptibility) and microstructural studies have been applied to understand how these interactions occurred with respect to pluton construction. The monzodiorites constituting the northwestern part of the pluton, which are composed of complexly zoned plagioclases or unzoned plagioclase laths, euhedral hornblende with biotite cores and acicular apatites, are characterized by abundant net veining, synplutonic dikes, microgranitoid enclaves, and juxtaposed series of discrete mafic-felsic pulses of hybrid nature with vertical syn-emplacement structures. The mingled interfaces between the diorites and granodiorites, on the other hand, are characterized by lobate contacts with interfingering of diorites into granodiorites at the decametric scale, abundant inclined to horizontal granitic pipes, breccia dykes and veins, which are strongly enriched in megacrysts of K-feldspars, and numerous swarms of

  5. Study of the Performance of Acoustic Barriers for Indiana Toll Roads

    OpenAIRE

    Suh, Sanghoon; Mongeau, Luc; BOLTON, J. Stuart

    2002-01-01

    The purpose of this study was to optimize the geometry and the acoustic properties of sound barriers for traffic noise applications. The approach consisted of developing and validating boundary element predictive models, which were subsequently exercised in order to refine the barrier characteristic and determine optimized configurations. The simple geometry of a circular disk was chosen to validate the boundary element model in the first part of this work. Experiments were performed in an an...

  6. Share and Share Alike: Barriers and Solutions to Tutorial Creation and Management

    Directory of Open Access Journals (Sweden)

    Anne-Marie Deitering

    2012-04-01

    Full Text Available Using data gathered in a nationwide survey, we found the most important barriers to tutorial creation for instruction librarians are time and technological expertise. Drawing on our experience extending the content management system used to build class pages and subject guides, we suggest using a content management system, like Library à la Carte, or LibGuides to build tutorials suggests a path around these common barriers.

  7. Heat-Activated Effect of Exchange Coupling Between Two Ferromagnets Separated by an Amorphous Semiconducting Barrier

    Institute of Scientific and Technical Information of China (English)

    肖明文; 李正中; 许望

    2002-01-01

    We try to extend our previous zero-temperature tunnelling theory for the exchange coupling between two ferromagnets separated by an amorphous semiconducting barrier to the case of finite temperature. The result exhibits that the tunnelling electrons can absorb or emit phonons when they tunnel through the amorphous barrier at finite temperatures so that the interlayer exchange coupling is heat activated. This agrees with the experiments.

  8. Scattering of light halo nuclei on heavy target at energies around the Coulomb barrier

    OpenAIRE

    Tengblad O.; Borge M.J.G.; Cubero M.; Nacher E.; Pesudo V.; Perea A.; Gomez-Camacho J.; Moro A. M.; Fernandez-Garcia J.P.; Alvarez M.A.G.; Rodriguez-Gallardo M.; Lay J. A.; Martel I.; Acosta L.; Sanchez-Benitez A.M.

    2014-01-01

    INPC 2013 – International Nuclear Physics Conference We report here on experiments performed at TRIUMF to study the scattering of the light halo nuclei 11Li on lead at energies below and around the Coulomb barrier. The the elastic and break-up differential cross section are interpreted in the framework of Continuum-Discretized Coupled-Channel calculations. The departure from Rutherford scattering at energies below the barrier is well beyond the behavior of normal nuclei Consejo Interins...

  9. Scattering of light halo nuclei on heavy target at energies around the Coulomb barrier

    Directory of Open Access Journals (Sweden)

    Tengblad O.

    2014-03-01

    Full Text Available We report here on experiments performed at TRIUMF to study the scattering of the light halo nuclei 11Li on lead at energies below and around the Coulomb barrier. The the elastic and break-up differential cross section are interpreted in the framework of Continuum-Discretized Coupled-Channel calculations. The departure from Rutherford scattering at energies below the barrier is well beyond the behavior of normal nuclei.

  10. Altered permeability barrier structure in cholesteatoma matrix

    DEFF Research Database (Denmark)

    Svane-Knudsen, Viggo; Halkier-Sørensen, Lars; Rasmussen, Gurli

    2002-01-01

    The stratum corneum of the cholesteatoma epithelium comprises the greater part of the cholesteatoma matrix. The permeability barrier that militates against diffusion and penetration of infectious and toxic agents into and through the epithelium is situated here. The multiple long sheets of lamellar...... lipid structures filling the intercellular spaces mainly control the barrier function. The barrier in cholesteatoma epithelium is several times thicker than in unaffected skin but presents distinctive features of a defective barrier as seen in other scaling skin diseases. The intercellular spaces appear...

  11. Barriers Approach to Innovation in Academic Libraries

    Directory of Open Access Journals (Sweden)

    Fu-Hsuan Chuang

    2016-11-01

    Full Text Available Innovation in academic libraries is not a brand new issue. Academic libraries can benefit from successful innovation, since innovation is a key contributor to gaining and sustaining competitive advantage for survival. Building on two case studies, 28 participants from leadership teams to practitioners are involved, the qualitative findings identified the specific two types of barriers that academic libraries face by applying a barriers approach to innovation, that’s, environmental and organizational barriers. Especially, seven dimensions of two types of barriers to innovation are found.

  12. The morphology and evolution of the Stromboli 2002-2003 lava flow field--An example of a basaltic flow field emplaced on a steep slope

    Science.gov (United States)

    Lodato, Luigi; Harris, A.; Spampinato, L.; Calvari, Sonia; Dehn, J.; Patrick, M.

    2007-01-01

    The use of a hand-held thermal camera during the 2002–2003 Stromboli effusive eruption proved essential in tracking the development of flow field structures and in measuring related eruption parameters, such as the number of active vents and flow lengths. The steep underlying slope on which the flow field was emplaced resulted in a characteristic flow field morphology. This comprised a proximal shield, where flow stacking and inflation caused piling up of lava on the relatively flat ground of the vent zone, that fed a medial–distal lava flow field. This zone was characterized by the formation of lava tubes and tumuli forming a complex network of tumuli and flows linked by tubes. Most of the flow field was emplaced on extremely steep slopes and this had two effects. It caused flows to slide, as well as flow, and flow fronts to fail frequently, persistent flow front crumbling resulted in the production of an extensive debris field. Channel-fed flows were also characterized by development of excavated debris levees in this zone (Calvari et al. 2005). Collapse of lava flow fronts and inflation of the upper proximal lava shield made volume calculation very difficult. Comparison of the final field volume with that expecta by integrating the lava effusion rates through time suggests a loss of ~70% erupted lava by flow front crumbling and accumulation as debris flows below sea level. Derived relationships between effusion rate, flow length, and number of active vents showed systematic and correlated variations with time where spreading of volume between numerous flows caused an otherwise good correlation between effusion rate, flow length to break down. Observations collected during this eruption are useful in helping to understand lava flow processes on steep slopes, as well as in interpreting old lava–debris sequences found in other steep-sided volcanoes subject to effusive activity.

  13. Ries Bunte Breccia revisited: Indications for the presence of water in Itzing and Otting drill cores and implications for the emplacement process

    Science.gov (United States)

    Pietrek, Alexa; Kenkmann, Thomas

    2016-07-01

    We reassessed two drill cores of the Bunte Breccia deposits of the Ries crater, Germany. The objectives of our study were the documentation of evidence for water in the Bunte Breccia, the evaluation of how that water influenced the emplacement processes, and from which preimpact water reservoir it was derived. The Bunte Breccia in both cores can be structured into a basal layer composed mainly of local substrate material, overlain by texturally and compositionally diverse, crater-derived breccia units. The basal layer is composed of the youngest sediments (Tertiary clays and Upper Jurassic limestone) and has a razor-sharp boundary to the upper breccia units, which are composed of older rocks of Upper Jurassic to Upper Triassic age. Sparse material exchange occurred between the basal layer and the rest of the Bunte Breccia. Fluids predominantly came from the Tertiary and the Upper Triassic sandstone formation. In the basal layer, Tertiary clays were subjected to intense, ductile deformation, indicating saturation with water. This suggests that water was mixed into the matrix, creating a fluidized basal layer with a strong shear localization. In the upper units, Upper Triassic sandstones are intensely deformed by granular flow. The texture requires that the rocks were disaggregated into granular sand. Vaporization of pore water probably aided fragmentation of these rocks. In the Otting core, hot suevite (T > 600 °C) covered the Bunte Breccia shortly after its emplacement. Vertically oriented gas escape pipes in suevite partly emanate directly at the contact to the Bunte Breccia. They indicate that the Bunte Breccia contained a substantial amount of water in the upper part that was vaporized and escaped through these vents.

  14. Potential and barriers for biogas production in Denmark at widely expanded organic farming with focus on the soil carbon content; Potentiale og barrierer for biogasproduktion i Danmark ved omfattende oekologisk jordbrug med fokus paa dyrkningsjordens kulstofforhold

    Energy Technology Data Exchange (ETDEWEB)

    Buch Salomonsen, K.

    2000-06-01

    The Ph.D. thesis describes the influence from continued expansion of organic farming systems to the potential for energy production from biogas in Denmark. The project analyses the consequence from three categories of barriers: 1) Practical barriers, 2) The attitude of organic farmers, and 3) Agricultural biological problems. Economic and political barriers are not examined. When the barriers can be quantified, they are included in the calculation of the maximum biogas potential. When not, the implications of barriers are expressed qualitatively. It has been a particular goal to provide new information on whether agricultural biological problems are a barrier to biogas production in organic farming systems. One important question in this connection is whether biogas production has a negative influence on the soil carbon content compared to composting. This question is investigated by an experiment. The project is based on technical and natural science disciplines, with an interdisciplinary basis ranging over energy planning, agricultural science, microbiology, and crop, and animal operation. (au)

  15. Reactive Membrane Barriers for Containment of Subsurface Contamination

    Energy Technology Data Exchange (ETDEWEB)

    William A. Arnold; Edward L. Cussler

    2007-02-26

    The overall goal of this project was to develop reactive membrane barriers--a new and flexible technique to contain and stabilize subsurface contaminants. Polymer membranes will leak once a contaminant is able to diffuse through the membrane. By incorporating a reactive material in the polymer, however, the contaminant is degraded or immobilized within the membrane. These processes increase the time for contaminants to breakthrough the barrier (i.e. the lag time) and can dramatically extend barrier lifetimes. In this work, reactive barrier membranes containing zero-valent iron (Fe{sup 0}) or crystalline silicotitanate (CST) were developed to prevent the migration of chlorinated solvents and cesium-137, respectively. These studies were complemented by the development of models quantifying the leakage/kill time of reactive membranes and describing the behavior of products produced via the reactions within the membranes. First, poly(vinyl alcohol) (PVA) membranes containing Fe{sup 0} and CST were prepared and tested. Although PVA is not useful in practical applications, it allows experiments to be performed rapidly and the results to be compared to theory. For copper ions (Cu{sup 2+}) and carbon tetrachloride, the barrier was effective, increasing the time to breakthrough over 300 times. Even better performance was expected, and the percentage of the iron used in the reaction with the contaminants was determined. For cesium, the CST laden membranes increased lag times more than 30 times, and performed better than theoretical predictions. A modified theory was developed for ion exchangers in reactive membranes to explain this result. With the PVA membranes, the effect of a groundwater matrix on barrier performance was tested. Using Hanford groundwater, the performance of Fe{sup 0} barriers decreased compared to solutions containing a pH buffer and high levels of chloride (both of which promote iron reactivity). For the CST bearing membrane, performance improved by a

  16. Pratt & Whitney thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bornstein, N. [United Technologies Research Center, East Hartford, CT (United States); Marcin, J. [Pratt & Whitney Aircraft Co., East Hartford, CT (United States)

    1995-10-01

    The objective of the Advanced Turbine Systems (ATS) Program is to develop ultra-high efficient, environmentally superior, and cost competitive gas turbine systems. The operating profiles of these industrial gas turbines are long, less cyclic with fewer transients-compared with those for aircraft gas turbine engines. Therefore, creep rather than thermal fatigue, becomes primary life-limiting for hot section components. Thermal barrier coatings (TBCs) will be used to achieve the objectives of the program. TBCs allow surface temperatures to increase without compromising the structural properties of the alloy. TBCs typically consist of a ceramic insulating layer, deposited onto the substrate with an intervening metallic layer, which imparts oxidation protection to the substrate and provides a surface to which the ceramic layer can adhere.

  17. Religious culture as a barrier?

    DEFF Research Database (Denmark)

    Agergaard, Sine

    2016-01-01

    Political interventions, media coverage and research often refer to the underrepresentation of ethnic minorities, particularly girls and women, participating in physical activity and organised sports. In both public and academic debates, reference is made to the religious culture as a particular...... barrier to participation in sports among Muslim girls and women. This article aims to provide a counter-narrative by focusing on young Muslim girls who simultaneously practice their religion and sports. The main research question was: How do young Danish Muslim girls align participation in sports...... religion as hegemonic, embodied and dynamic cultural phenomena, the analysis points to the diversity through which Muslim girls and women participate and engage in sports. Finally, the article discusses the extent to which counter-narratives may contribute to changing perspectives on so-called hard...

  18. Lactulose as a marker of intestinal barrier function in pigs after weaning

    NARCIS (Netherlands)

    Wijtten, P.J.A.; Verstijnen, J.J.; Kempen, van T.A.T.G.; Perdok, H.B.; Gort, G.; Verstegen, M.W.A.

    2011-01-01

    Intestinal barrier function in pigs after weaning is almost exclusively determined in terminal experiments with Ussing chambers. Alternatively, the recovery in urine of orally administered lactulose can be used to assess intestinal permeability in living animals. This experiment was designed to stud

  19. Cumulative Effects of Barriers on the Movements of Forest Birds

    Directory of Open Access Journals (Sweden)

    Marc Bélisle

    2002-01-01

    Full Text Available Although there is a consensus of opinion that habitat fragmentation has deleterious effects on animal populations, primarily by inhibiting dispersal among remaining patches, there have been few explicit demonstrations of the ways by which degraded habitats actually constrain individual movement. Two impediments are primarily responsible for this paucity: it is difficult to separate the effects of habitat fragmentation (configuration from habitat loss (composition, and conventional measures of fragmented habitats are assumed to be, but probably are not, isotropic. We addressed these limitations by standardizing differences in forest cover in a clearly anisotropic configuration of habitat fragmentation by conducting a homing experiment with three species of forest birds in the Bow Valley of Banff National Park, Canada. Birds were translocated (1.2-3.5  km either parallel or perpendicular to four/five parallel barriers that are assumed to impede the cross-valley travel of forest-dependent animals. Taken together, individuals exhibited longer return times when they were translocated across these barriers, but differences among species suggest a more complex interpretation. A long-distance migrant (Yellow-rumped Warbler, Dendroica coronata behaved as predicted, but a short-distance migrant (Golden-crowned Kinglet, Regulus satrapa was indifferent to barrier configuration. A resident (Red-breasted Nuthatch, Sitta canadensis exhibited longer return times when it was translocated parallel to the barriers. Our results suggest that an anisotropic arrangement of small, open areas in fragmented landscapes can have a cumulative barrier effect on the movement of forest animals, but that both modelers and managers will have to acknowledge potentially counterintuitive differences among species to predict the effect that these may have on individual movement and, ultimately, dispersal.

  20. Elements modulating the prion species barrier and its passage consequences.

    Directory of Open Access Journals (Sweden)

    Juan-Maria Torres

    Full Text Available The specific characteristics of Transmissible Spongiform Encephalopathy (TSE strains may be altered during passage across a species barrier. In this study we investigated the biochemical and biological characteristics of Bovine Spongiform Encephalopathy (BSE after transmission in both natural host species (cattle, sheep, pigs and mice and in transgenic mice overexpressing the corresponding cellular prion protein (PrPC in comparison with other non-BSE related prions from the same species. After these passages, most features of the BSE agent remained unchanged. BSE-derived agents only showed slight modifications in the biochemical properties of the accumulated PrPSc, which were demonstrated to be reversible upon re-inoculation into transgenic mice expressing bovine-PrPC. Transmission experiments in transgenic mice expressing bovine, porcine or human-PrP revealed that all BSE-derived agents were transmitted with no or a weak transmission barrier. In contrast, a high species barrier was observed for the non-BSE related prions that harboured an identical PrP amino acid sequence, supporting the theory that the prion transmission barrier is modulated by strain properties (presumably conformation-dependent rather than by PrP amino acid sequence differences between host and donor. As identical results were observed with prions propagated either in natural hosts or in transgenic mouse models, we postulate that the species barrier and its passage consequences are uniquely governed by the host PrPC sequence and not influenced by other host genetic factors. The results presented herein reinforce the idea that the BSE agent is highly promiscuous, infecting other species, maintaining its properties in the new species, and even increasing its capabilities to jump to other species including humans. These data are essential for the development of an accurate risk assessment for BSE.

  1. Comparative Analysis: Potential Barriers to Career Participation by North American Physicians in Global Health

    Directory of Open Access Journals (Sweden)

    Daniel S. Rhee

    2014-01-01

    Full Text Available Physician interest in global health, particularly among family physicians, is reflected by an increasing proliferation of field training and service experiences. However, translating initial training involvement into a defined and sustainable global health career remains difficult and beset by numerous barriers. Existing global health literature has largely examined training experiences and related ethical considerations while neglecting the role of career development in global health. To explore this, this paper extrapolates potential barriers to global health career involvement from existing literature and compares these to salary and skills requirements for archetypal physician positions in global health, presenting a framework of possible barriers to sustained physician participation in global health work. Notable barriers identified include financial limitations, scheduling conflicts, security/family concerns, skills limitations, limited awareness of opportunities, and specialty choice, with family practice often closely aligned with global health experience. Proposed solutions include financial support, protected time, family relocation support, and additional training. This framework delineates barriers to career involvement in global health by physicians. Further research regarding these barriers as well as potential solutions may help direct policy and initiatives to better utilize physicians, particularly family physicians, as a valuable global health human resource.

  2. Simulation of energy barrier distributions using real particle parameters and comparison with experimental obtained results

    Energy Technology Data Exchange (ETDEWEB)

    Büttner, M., E-mail: Markus.Buettner@uni-jena.de [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Helmholtzweg 5, 07743 Jena (Germany); Schiffler, M. [Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena (Germany); Weber, P.; Seidel, P. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Helmholtzweg 5, 07743 Jena (Germany)

    2013-11-15

    Distributions of energy barriers in systems of magnetic nanoparticles have been calculated by means of the path integral method and the results have been compared with distributions previously obtained in our experiments by means of the temperature dependent magnetorelaxation method. The path integral method allowed to obtain energies of the interactions of magnetic moments of nanoparticles with axes of their easy magnetisation as well as energies of mutual interactions of magnetic moments. Calculated distributions of energy barriers have been described satisfactorily by curves of the lognormal distribution. We found an agreement between the theory and the experiment at temperatures above approximately 100 K. The influence of the volume concentration of nanoparticles and agglomeration on the energy barrier distribution has been investigated. - Highlights: • The path integral method of calculation allows to satisfactorily reproduce the quantitative experimental results. • The simulations of the energy barrier distributions reflect the lognormal distribution of the MNP found in real experiments. • Higher particle volume concentration leads to a broadening of the simulated energy barrier distribution. • At low particle concentration there is only anisotropy energy. • In case of agglomeration the energy barrier distribution broadens.

  3. Thermal Barrier Coatings on Copper Substrates for Rocket Applications

    Science.gov (United States)

    Schloesser, Jana; Fedorova, Tatiana; Bäker, Martin; Rösler, Joachim

    Currently a new generation of relaunchable space transportation system using liquid hydrogen/ liquid oxygen rocket engines is under development. The inner combustion chamber is exposed to extreme thermal loads and environmental attack during starts. To prevent failure of the cooling channels, a thermal barrier coating to provide thermal and oxidation protection could be applied. Thermal barrier coatings are state of the art for gas turbines and this concept should be transferred to copper substrates in rocket engine applications. The thermomechanical loading conditions are quite different from the gas turbine applications as heat fluxes and temperature gradients are much higher while overall service time is much shorter. As a start for optimization of a suitable coating, a material system known for gas turbines is employed. In this work a thermal barrier coating system is applied by atmospheric plasma spraying to the copper-based high strength alloy Cu-1%Cr-0.3%Zr. The bond coat consists of a NiCrAlY alloy, while partially stabilized zirconia is used as a top coat. Spraying parameter optimization for the new substrate is described. The reached coating system is tested in thermal cycling experiments, where no failure of the coating could be detected. In oxidation experiments good environmental protection of the coating is shown.

  4. The Status of Industrial Ecology in Australia: Barriers and Enablers

    Directory of Open Access Journals (Sweden)

    Glen D. Corder

    2014-03-01

    Full Text Available Drawing on current international industrial ecology thinking and experiences with Australian initiatives, this article critically overviews the current status of industrial ecology in Australia and examines the barriers and potential strategies to realise greater uptake and application of the concept. The analysis is conducted across three categories: heavy industrial areas (including Kwinana and Gladstone, mixed industrial parks (Wagga Wagga and Port Melbourne, and waste exchange networks, and identifies the past and future significance of seven different types of barriers—regulation, information, community, economic, technical, cooperation and trust, commitment to sustainable development—for each of the three categories. The outcomes from this analysis highlight that regulation, information, and economic barriers for heavy industrial area and mixed industrial parks, and economic and technical barriers for waste exchange networks are the current and future focus for industrial ecology applications in Australia. These findings appear to be consistent with recently published frameworks and learnings. The authors propose key questions that could enhance greater adoption of industrial ecology applications in Australia and acknowledge that international research and experiences, while partly providing answers to these questions, need to be adapted and refined for the Australian context.

  5. Autistic barriers in the psychoanalysis of borderline adults.

    Science.gov (United States)

    Cohen, D; Jay, S M

    1996-10-01

    The authors discuss Frances Tustin's work on childhood autism in order to clarify the nature and protective function of autistic barriers in adult patients who present challenging resistances in treatment. Tustin's thesis is that childhood autism constitutes a massive formation of avoidance reactions that develop in infancy to ward off traumatic awareness of bodily separateness. She describes two forms of childhood pathology that may develop: the encapsulated child who defends against all 'not me' experience by means of self-generated bodily sensations that augment the illusion of complete bodily continuity with the mother; and the entangled child who generates a protective illusion of being enfolded inside the body of the mother to minimise the experience of separateness. The transference resistances of borderline adults can be categorised according to Tustin's typology of encapsulation and entanglement. Clinical material is presented from the analyses of two borderline patients, one encapsulated and the other entangled. Despite seemingly different transference manifestations, both belong to the category of autistic barriers inasmuch as they ward off awareness of separation-induced injury to the primal self. The countertransference difficulties that the analyst encounters with patients who employ autistic barriers are discussed and treatment issues are reviewed.

  6. Chemical gel barriers as low-cost alternative to containment and in situ cleanup of hazardous wastes to protect groundwater

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    Chemical gel barriers are being considered as a low-cost alternative for containment and in situ cleanup of hazardous wastes to protect groundwater. Most of the available gels in petroleum application are non-reactive and relative impermeable, providing a physical barriers for all fluids and contaminants. However, other potential systems can be envisioned. These systems could include gels that are chemically reactive and impermeable such that most phase are captured by the barriers but the contaminants could diffuse through the barriers. Another system that is chemically reactive and permeable could have potential applications in selectivity capturing contaminants while allowing water to pass through the barriers. This study focused on chemically reactive and permeable gel barriers. The gels used in experiment are DuPont LUDOX SM colloidal silica gel and Pfizer FLOPAAM 1330S hydrolyzed polyacrylamide (HPAM) gel.

  7. Identifying real and perceived barriers to therapeutic education programs for individuals with inflammatory arthritis.

    Science.gov (United States)

    Bain, Lorna; Sangrar, Ruheena; Bornstein, Carolyn; Lukmanji, Sara; Hapuhennedige, Sandani; Thorne, Carter; Beattie, Karen A

    2016-09-01

    Therapeutic Education Programs (TEPs) grounded in self-management principles have been shown to improve quality of life of patients with chronic conditions and reduce patient-related healthcare costs. Though these programs are becoming more readily available, patients often experience barriers in participating. This study sought to identify barriers faced by inflammatory arthritis (IA) patients in attending a TEP and understand how patients overcame perceived barriers. A mixed-method study design was used. Questionnaires were distributed to individuals with IA who were invited to attend a TEP between 2010 and 2013. Respondents were those that chose not to attend (group A), individuals who attended ≤4 of 10 sessions (group B), individuals who attended ≥5 of 10 sessions prior to May 2013 (group C), and individuals who attended ≥5 of 10 sessions from June 2013 to November 2013 (group D). Individuals in group D were also invited to participate in focus groups to discuss how they had overcome perceived barriers. Real barriers identified by individuals in groups A and B included time, distance, and cost associated with attendance. Individuals who overcame perceived barriers (groups C and D) discussed strategies they used to do so. Aspects of the overall program experience and access to clinic and program also contributed to patients being able to overcome barriers. Time, distance, and cost are external barriers that prevented individuals from utilizing self-management education opportunities. These barriers were overcome if and when individuals had resources available to them. Readiness for behavior change also influenced commitment to participate in the program.

  8. Barriers to Psychosocial Services among Homeless Women Veterans.

    Science.gov (United States)

    Hamilton, Alison B; Poza, Ines; Hines, Vivian; Washington, Donna L

    2012-01-01

    Veterans comprise a disproportionate fraction of the nation's homeless population, with women veterans up to four times more likely to be homeless than non-veteran women. This paper provides a grounded description of barriers to psychosocial services among homeless women veterans. Three focus groups were held in Los Angeles, CA, with a total of 29 homeless women veterans. These women described three primary, proximal (current) barriers: lack of information about services, limited access to services, and lack of coordination across services. Compared to non-veteran homeless women, women veterans potentially face additional challenges of trauma exposure during military service, post-military readjustment issues, and few services specific to women veterans. Understanding their service needs and experiences is critical to the development of relevant and appropriate services that move homeless women veterans away from vulnerability, into safety.

  9. Effectuation in the undergraduate classroom: Three barriers to entrepreneurial learning

    DEFF Research Database (Denmark)

    Günzel-Jensen, Franziska; Robinson, Sarah

    2017-01-01

    at exploring how students, who are novice entrepreneurs, react to working effectually and which barriers they face when applying effectual decision making logics in a university course. Design/methodology/approach: A student-centered process course in entrepreneurship with 142 students provides an unique...... opportunity to explore the phenomena. Participant/teacher observations, written and oral work from the students and finally formal and informal written evaluations of the course by the students provide comprehensive data. Findings: We find that students experience three barriers to using effectuation...... entrepreneurs in the classroom, second, to articulate the factors that hinder entrepreneurial learning when effectuation is used in a process course and third, to shed light on the importance of contextual factors for individual learning....

  10. Identifying barriers for implementation of computer based nursing documentation.

    Science.gov (United States)

    Vollmer, Anna-Maria; Prokosch, Hans-Ulrich; Bürkle, Thomas

    2014-01-01

    This study was undertaken in the planning phase for the introduction of a comprehensive computer based nursing documentation system at Erlangen University Hospital. There, we expect a wide range of difficult organizational changes, because the nurses currently neither used computer based nursing documentation nor did they follow strongly the nursing process model within paper based documentation. Thus we were eager to recognize potential pitfalls early and to identify potential barriers for digital nursing documentation. In a questionnaire study we surveyed all German university hospitals for their experience with the implementation of computer based nursing documentation implementation. We received answers from 11 of the 23 hospitals. Furthermore we performed a questionnaire study about expectations and fears among the nurses of four pilot wards of our hospital. Most respondents stated a positive attitude towards the nursing process documentation, but many respondents note technical (e.g. bad performance of the software) and organizational barriers (e.g. lack of time).

  11. Barriers to qualitative dementia research: the elephant in the room.

    Science.gov (United States)

    Carmody, John; Traynor, Victoria; Marchetti, Elena

    2015-07-01

    As our population is aging, the global prevalence of dementia is rising. Recent extensive reviews of the dementia literature highlight a clear need for additional qualitative research to address the experiences of people with dementia and their carers. To date, the vast majority of published dementia research is quantitative in nature and, perhaps not surprisingly, attracts the bulk of government funding. In contrast, qualitative dementia research is poorly resourced and less frequently published. Although a myriad of factors are responsible for this dichotomy, we propose that inadequate funding represents the "elephant in the room" of dementia research. In this article, we describe and emphasize the need for qualitative dementia research, highlight existing barriers, and outline potential solutions. Examples of barriers are provided and theoretical underpinnings are proposed.

  12. A preliminary experimental study on virtual sound barrier system

    Science.gov (United States)

    Zou, Haishan; Qiu, Xiaojun; Lu, Jing; Niu, Feng

    2007-10-01

    Virtual sound barrier (VSB) is an array of loudspeakers and microphones forming an acoustic barrier, which creates a quiet zone without blocking air and light. A 16-channel cylindrical VSB system has been developed and its feasibility is verified by both numerical simulations and experiments. Experimental results in a normal room show that it can create a quiet zone larger than the size of a human head in the low-middle frequency, with a total sound pressure level reduction of more than 10 dB in the quiet zone. The control performance of the system with respect to the frequency, the distribution of the error sensors and the control sources are discussed.

  13. Clays in natural and engineered barriers for radioactive waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    Andra organised an International Symposium on the use of Natural and Engineered Clay-based Barriers for the Containment of Radioactive Waste hold at the Congress Centre of Tours, France, in March 2005. The symposium provided an opportunity to take stock of the potential properties of the clay-based materials present in engineered or natural barriers in order to meet the containment specifications of a deep geological repository for radioactive waste. It was intended for specialists working in the various disciplines involved with clays and clay based minerals, as well as scientists from agencies and organisations dealing with investigations on the disposal of high-level and long-lived radioactive waste. The themes of the Symposium included geology, geochemistry, transfers of materials, alteration processes, geomechanics, as well as the recent developments regarding the characterisation of clays, as well as experiments in surface and underground laboratories. The symposium consisted of plenary sessions, parallel specialized sessions and poster sessions. (author)

  14. Lipids and skin barrier function - a clinical perspective

    DEFF Research Database (Denmark)

    Jungersted, J.M.; Hellgren, Lars; Jemec, G.B.E.

    2008-01-01

    and in particular, the role of barrier function in the pathogenesis of skin disease and its subsequent treatment protocols. The 3 major lipids in the SC of importance are ceramides, free fatty acids, and cholesterol. Human studies comparing levels of the major SC lipids in patients with atopic dermatitis...... and healthy controls have suggested a possible role for ceramide 1 and to some extent ceramide 3 in the pathogenesis of the disease. Therapies used in diseases involving barrier disruption have been sparely investigated from a lipid perspective. It has been suggested that ultraviolet light as a treatment......The stratum corneum (SC) protects us from dehydration and external dangers. Much is known about the morphology of the SC and penetration of drugs through it, but the data are mainly derived from in vitro and animal experiments. In contrast, only a few studies have the human SC lipids as their focus...

  15. Strategies for monitoring of priority pollutant emission barriers

    DEFF Research Database (Denmark)

    Pettersson, Maria; De Keyser, Webbey; Birch, Heidi;

    2010-01-01

    The objective of Task 7.5 was to develop tools for model-based planning of sampling campaigns in the design of monitoring strategies for priority pollutant emission barriers. Using integrated urban wastewater system (IUWS) models, measurement campaigns can be designed to improve the calibration...... of the model‟s parameters (Optimal Experiment Design for Parameter Estimation (OED/PE)). Furthermore, the knowledge contained in the IUWS models can be used to optimize the planning of sampling campaigns aiming at assessing the efficiency of emission control strategies. To do this, the emission barriers need...... to be implemented in the IUWS model, as well as the sampling and measuring devices that will be used. The simulation results are presented as a Substance Flow Analysis (SFA). These SFAs can be compared with empirical SFAs and can also be used to set up measurement campaigns aiming at gathering information...

  16. Crash barrier research in the Netherlands.

    NARCIS (Netherlands)

    Flury, F.C. & Paar, H.G.

    1973-01-01

    Research by the SWOV has led to the development of a series of crash barriers of basically the same design but with varying degrees of resistance to lateral deflection. Requirements to which in general a crash barrier should fulfill are presented.

  17. Assessment of blood-retinal barrier integrity.

    Science.gov (United States)

    Vinores, S A

    1995-01-01

    The blood-retinal barrier consists of two components which are comprised of the retinal vascular endothelium and the retinal pigment epithelium, respectively. Its functional integrity can be recognized by tight junctions between these cells with a paucity of endocytic vesicles within them and the presence of the molecules that regulate the ionic and metabolic gradients that constitute the barrier. The barrier is compromised in several disease processes and by a variety of agents, but in most cases the location and mechanism for barrier failure is not understood. Perfusion with a variety of radiolabeled tracer molecules, vitreous fluorophotometry, or magnetic resonance imaging can be used to quantitate blood-retinal barrier leakage. Fluorescein angiography or magnetic resonance imaging can localize sites of leakage in vivo with limited resolution. Evans blue dye can be used to visualize blood-retinal barrier failure in gross pathological specimens and immuno-histochemical labeling of serum proteins such as albumin or fibrinogen can be used to localize sites of blood-retinal barrier breakdown by light microscopy. Tracers such as horseradish peroxidase, microperoxidase, or lanthanum, or the immunocytochemical demonstration of albumin can be used to reveal blood-retinal barrier breakdown at the ultrastructural level and provide insights into the mechanisms involved. This review discusses the advantages and limitations of each of these methods to aid in selection of the appropriate techniques to derive the desired information.

  18. Fracture mechanism of a thermal barrier coating

    Science.gov (United States)

    Samoilenko, V. M.; Ravilov, R. G.; Drevnyak, V. V.; Petrova, M. A.

    2016-06-01

    The fracture mechanism of the thermal barrier coating of gas turbine blades is studied. The causes of the fracture of the ceramic layer are discussed and the possible ways to increase the fatigue life of the thermal barrier coating are considered.

  19. Barriers to adherence in cystic fibrosis

    DEFF Research Database (Denmark)

    Bregnballe, Vibeke; Schiøtz, Peter Oluf

    2012-01-01

    Danish patients with cystic fibrosis aged 14 to 25 years and their parents. Conclusions: The present study showed that the majority of adolescents with CF and their parents experienced barriers to treatment adherence. Patients and parents agreed that the three most common barriers encountered lack...

  20. Storm impacts on small barrier islands

    DEFF Research Database (Denmark)

    Kroon, Aart; Fruergaard, Mikkel

    The shorelines of the Baltic Sea and the inner coastal waters in Denmark consist of many barrier islands. These sandy barrier islands were mainly formed in the Holocene and are still very dynamic. The present day changes in the morphology are dominantly governed by storm waves and associated high...

  1. Nurses' barriers to learning: an integrative review.

    Science.gov (United States)

    Santos, Marion C

    2012-07-01

    This integrative review of the literature describes nurses' barriers to learning. Five major themes emerged: time constraints, financial constraints, workplace culture, access/relevance, and competency in accessing electronic evidence-based practice literature. The nurse educator must address these barriers for the staff to achieve learning and competency.

  2. Antimicrobial Peptides, Infections and the Skin Barrier

    DEFF Research Database (Denmark)

    Clausen, Maja-Lisa; Agner, Tove

    2016-01-01

    The skin serves as a strong barrier protecting us from invading pathogens and harmful organisms. An important part of this barrier comes from antimicrobial peptides (AMPs), which are small peptides expressed abundantly in the skin. AMPs are produced in the deeper layers of the epidermis...

  3. Clays in natural and engineered barriers for radioactive waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    The meeting covers all topics concerning natural argillaceous geological barriers and the clay material based engineered barrier systems, investigated by means of: laboratory experiments on clay samples (new analytical developments), in situ experiments in underground research laboratories, mock-up demonstrations, natural analogues, as well as numerical modelling and global integration approaches (including up-scaling processes and treatment of uncertainties). The works presented deal with: examples of broad research programs (national or international) on the role of natural and artificial clay barriers for radionuclide confinement; clay-based repository concepts: repository designs, including technological and safety issues related to the use of clay for nuclear waste confinement; geology and clay characterisation: mineralogy, sedimentology, paleo-environment, diagenesis, dating techniques, discontinuities in rock clay, fracturing, self sealing processes, role of organic matter and microbiological processes; geochemistry: pore water geochemistry, clay thermodynamics, chemical retention, geochemical modelling, advanced isotopic geochemistry; mass transfer: water status and hydraulic properties in low permeability media, pore space geometry, water, solute and gas transfer processes, colloid mediated transport, large scale movements, long-term diffusion; alteration processes: oxidation effects, hydration-dehydration processes, response to thermal stress, iron-clay interactions, alkaline perturbation; geomechanics: thermo-hydro-mechanical behaviour of clay, rheological models, EDZ characterisation and evolution, coupled behaviour and models (HM, THM, THMC). A particular interest is given to potential contributions coming from fields of activities other than radioactive waste management, which take advantage of the confinement properties of the clay barrier (oil and gas industries, gas geological storage, CO{sub 2} geological sequestration, chemical waste isolation