Science.gov

Sample records for long-term flow testing

  1. Long-term testing

    NASA Astrophysics Data System (ADS)

    Ferber, M.; Graves, G. A., Jr.

    Land-based gas turbines are significantly different from automotive gas turbines in that they are designed to operate for 50,000 h or greater (compared to 5,000-10,000 h). The primary goal of this research is to determine the long-term survivability of ceramic materials for industrial gas turbine applications. Research activities in this program focus on the evaluation of the static tensile creep and stress rupture (SR) behavior of three commercially available structural ceramics which have been identified by the gas turbine manufacturers as leading candidates for use in industrial gas turbines. For each material investigated, a minimum of three temperatures and four stresses will be used to establish the stress and temperature sensitivities of the creep and SR behavior. Because existing data for many candidate structural ceramics are limited to testing times less than 2,000 h, this program will focus on extending these data to times on the order of 10,000 h, which represents the lower limit of operating time anticipated for ceramic blades and vanes in gas turbine engines. A secondary goal of the program will be to investigate the possibility of enhancing life prediction estimates by combining interrupted tensile SR tests and tensile dynamic fatigue tests in which tensile strength is measured as a function of stressing rate. The third goal of this program will be to investigate the effects of water vapor upon the SR behavior of the three structural ceramics chosen for the static tensile studies by measuring the flexural strength as a function of stressing rate at three temperatures.

  2. Long-term testing

    SciTech Connect

    Ferber, M.; Graves, G.A. Jr.

    1994-12-31

    Land-based gas turbines are significantly different from automotive gas turbines in that they are designed to operate for 50,000 h or greater (compared to 5,000--10,000 h). The primary goal of this research is to determine the long-term survivability of ceramic materials for industrial gas turbine applications. Research activities in this program focus on the evaluation of the static tensile creep and stress rupture (SR) behavior of three commercially available structural ceramics which have been identified by the gas turbine manufacturers as leading candidates for use in industrial gas turbines. For each material investigated, a minimum of three temperatures and four stresses will be used to establish the stress and temperature sensitivities of the creep and SR behavior. Because existing data for many candidate structural ceramics are limited to testing times less than 2,000 h, this program will focus on extending these data to times on the order of 10,000 h, which represents the lower limit of operating time anticipated for ceramic blades and vanes in gas turbine engines. A secondary goal of the program will be to investigate the possibility of enhancing life prediction estimates by combining interrupted tensile SR tests and tensile dynamic fatigue tests in which tensile strength is measured as a function of stressing rate. The third goal of this program will be to investigate the effects of water vapor upon the SR behavior of the three structural ceramics chosen for the static tensile studies by measuring the flexural strength as a function of stressing rate at three temperatures.

  3. HDR opportunities and challenges beyond the long-term flow test

    SciTech Connect

    Duchane, D.V.

    1992-01-01

    The long term flow test (LTFT) of the world's largest, deepest, and hottest hot dry rock (HDR) reservoir currently underway at Fenton Hill, NM, is expected to demonstrate that thermal energy can be mined from hot rock within the earth on a sustainable basis with minimal water consumption. This test will simulate the operations of a commercial facility in some ways, but it will not show that energy from HDR can be produced at a variety of locations with different geological settings. Since the Fenton Hill system was designed as a research facility rather than strictly for production purposes, it will also not demonstrate economic viability, although it may well give indications of system modifications needed for economic HDR operations. A second production site must be constructed, ideally under the direction of the private geothermal community, to begin the process of proving that the vast HDR resources can be accessed on a worldwide scale. Finally, research and development work in areas such as reservoir interrogation, and system modeling must be accelerated to increase the competitiveness and geographical applications of HDR and the geothermal industry in general. This paper addresses the above issues in detail and outlines possible paths to future prosperity for the commercial geothermal industry.

  4. Long-term durability testing of ceramic cross-flow filter. Final report, September 29, 1987--December 31, 1992

    SciTech Connect

    Lippert, T.E.; Smeltzer, E.E.; Alvin, M.A.; Bachovchin, D.M.

    1993-08-01

    Long term durability testing of the cross flow filter is described. Two high temperature, high pressure test facilities were built and operated. The facilities were designed to simulate dirty gas environments typical of Pressurized Fluidized Bed Combustion (PFBC) and coal gasification. Details of the design and operation of the test facilities and filter testing results are described.

  5. HDR Opportunities and Challenges Beyond the Long-Term Flow Test

    SciTech Connect

    Duchane, David

    1992-03-24

    The long term flow test (LTFT) of the worlds largest, deepest, and hottest hot dry rock (HDR) reservoir currently underway at Fenton Hill, NM, is expected to demonstrate that thermal energy can be mined from hot rock within the earth on a sustainable basis with minimal water consumption. This test will simulate the operations of a commercial facility in some ways, but it will not show that energy from HDR can be produced at a variety of locations with different geological settings. Since the Fenton Hill system was designed as a research facility rather than strictly for production purposes, it will also not demonstrate economic viability, although it may well give indications of system modifications needed for economic HDR operations. A second production site must be constructed, ideally under the direction of the private geothermal community, to begin the process of proving that the vast HDR resources can be accessed on a worldwide scale. This facility should be designed and engineered to produce and market energy at competitive prices. At the same time, a wide variety of techniques to advance the state-of-the-art of HDR technology must be pursued to develop this infant technology rapidly to its maximum potential. A number of design and operational techniques have been conceived which may lead to improved economics in HDR systems. After careful technical and economic scrutiny, those showing merit should be vigorously pursued. Finally, research and development work in areas such as reservoir interrogation, and system modeling must be accelerated to increase the competitiveness and geographical applications of HDR and the geothermal industry in general. This paper addresses the above issues in detail and outlines possible paths to future prosperity for the commercial geothermal industry.

  6. Pre-test estimates of temperature decline for the LANL Fenton Hill Long-Term Flow Test

    SciTech Connect

    Robinson, B.A.; Kruger, P.

    1992-06-01

    Pre-test predications for the Long-Term Flow Test (LTFT) of the experimental Hot Dry Rock (HDR) reservoir at Fenton Hill were made using two models. Both models are dependent on estimates of the ``effective`` reservoir volume accessed by the fluid and the mean fracture spacing (MFS) of major joints for fluid flow. The effective reservoir volume was estimated using a variety of techniques, and the range of values for the MFS was set through experience in modeling the thermal cooldown of other experimental HDR reservoirs. The two pre-test predictions for cooldown to 210{degrees}C (a value taken to compare the models) from initial temperature of 240{degrees}C are 6.1 and 10.7 years. Assuming that a minimum of 10{degrees}C is required to provide an unequivocal indication of thermal cooldown, both models predict that the reservoir will not exhibit observable cooldown for at least two years.

  7. Progress report on the long-term flow testing of the HDR reservoir at Fenton Hill, New Mexico

    SciTech Connect

    Brown, Donald W.; Du Teau, Robert

    1993-01-28

    Through mid-December 1992, long-term flow testing of the Phase I1 Hot Dry Rock (HDR) reservoir at Fenton Hill, NM has been conducted for an aggregate of 24 weeks at near-optimum aseismic injection conditions. This period of flow testing, which began on April 9, 1992, included several reservoir shut-ins due to equipment problems and an intervening lower-injection-rate Interim Flow Test lasting about 6 weeks. With the exceptions noted above, the majority of the flow testing for that period was conducted at an average injection rate of 7.2 l/s and at pressures up to 27.3 MPa. However, this high level of injection pressure has not produced any discernible reservoir microseismicity, indicating that we have been operating the reservoir at pressures below the threshold for fracture extension. The permeation loss from the boundaries of the reservoir at these elevated pressures has averaged about 0.7 l/s, a very low rate of water loss considering the very large volume of fractured rock (about 16x106 m³) comprising the pressure-stimulated reservoir region. Temperature logging across the 350-m production interval, centered at a depth of about 3500 m, indicates that there has been no measurable drop in the mixed-mean reservoir production temperature at the top of this interval since the time of our first temperature log in mid July. Most recently, we have conducted additional intermittent reservoir testing at higher levels of production backpressure during a period of reservoir pressure maintenance using a high-capacity rental triplex mud pump.

  8. A groundwater flow and transport model of long-term radionuclide migration in central Frenchman flat, Nevada test site

    SciTech Connect

    Kwicklis, Edward Michael; Becker, Naomi M; Ruskauff, Gregory; De Novio, Nicole; Wilborn, Bill

    2010-11-10

    A set of groundwater flow and transport models were created for the Central Testing Area of Frenchman Flat at the former Nevada Test Site to investigate the long-term consequences of a radionuclide migration experiment that was done between 1975 and 1990. In this experiment, radionuclide migration was induced from a small nuclear test conducted below the water table by pumping a well 91 m away. After radionuclides arrived at the pumping well, the contaminated effluent was discharged to an unlined ditch leading to a playa where it was expected to evaporate. However, recent data from a well near the ditch and results from detailed models of the experiment by LLNL personnel have convincingly demonstrated that radionuclides from the ditch eventually reached the water table some 220 m below land surface. The models presented in this paper combine aspects of these detailed models with concepts of basin-scale flow to estimate the likely extent of contamination resulting from this experiment over the next 1,000 years. The models demonstrate that because regulatory limits for radionuclide concentrations are exceeded only by tritium and the half-life of tritium is relatively short (12.3 years), the maximum extent of contaminated groundwater has or will soon be reached, after which time the contaminated plume will begin to shrink because of radioactive decay. The models also show that past and future groundwater pumping from water supply wells within Frenchman Flat basin will have negligible effects on the extent of the plume.

  9. Long term thermoelectric module testing system.

    PubMed

    D'Angelo, Jonathan; Hogan, Timothy

    2009-10-01

    Thermoelectric generators can be used for converting waste heat into electric power. Significant interest in developing new materials in recent years has led to the discovery of several promising thermoelectrics, however, there can be considerable challenges in developing the materials into working devices. Testing and feedback is needed at each step to gain valuable information for identification of difficulties, quality of the materials and modules, repeatability in fabrication, and longevity of the devices. This paper describes a long-term module testing system for monitoring the output power of a module over extended testing times. To evaluate the system, we have tested commercially available thermoelectric modules over a one month time period. PMID:19895086

  10. Contaminant transfer and hydrodispersive parameters in basaltic lava flows: artificial tracer test and implications for long-term management

    NASA Astrophysics Data System (ADS)

    Bertrand, G.; Celle-Jeanton, H.; Huneau, F.; Baillieux, A.; Mauri, G.; Lavastre, V.; Undereiner, G.; Girolami, L.; Moquet, J. S.

    2015-10-01

    The aim of this paper is to evaluate the vulnerability after point source contamination and characterize water circulations in volcanic flows located in the Argnat basin volcanic system (Chaîne des Puys, French Massif Central) using a tracer test performed by injecting a iodide solution. The analysis of breakthrough curves allowed the hydrodispersive characteristics of the massive lava flows to be determined. Large Peclet numbers indicated a dominant advective transport. The multimodal feature of breakthrough curves combined with high values of mean velocity and low longitudinal dispersion coefficients indicated thatwater flows in an environment analogous to a fissure system, and only slightly interacts with a low porosity matrix (ne < 1%). Combining this information with lava flow stratigraphy provided by several drillings allowed a conceptual scheme of potential contaminant behaviour to be designed. Although lava flows are vulnerable to point source pollution due to the rapid transfer of water within fractures, the saturated scoriaceous layers located between massive rocks should suffice to strongly buffer the transit of pollution through dilution and longer transit times. This was consistent with the low recovery rate of the presented tracer test.

  11. Long-term corrosion testing pan.

    SciTech Connect

    Wall, Frederick Douglas; Brown, Neil R.

    2008-08-01

    This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing needs. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to meet all future testing needs, given that all testing is consolidated to a single location. This report is a revision to SAND2007-7027 to address DOE comments and add a series of tests to address NWTRB recommendations.

  12. Long-term corrosion testing plan.

    SciTech Connect

    Wall, Frederick Douglas; Brown, Neil R.

    2009-02-01

    This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing program. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to accommodate all future testing, given that all testing is consolidated to a single location. This report is a revision to SAND2008-4922 to address DOE comments.

  13. Online Continuous Flow Differential Electrochemical Mass Spectrometry with a Realistic Battery Setup for High-Precision, Long-Term Cycling Tests.

    PubMed

    Berkes, Balázs B; Jozwiuk, Anna; Vračar, Miloš; Sommer, Heino; Brezesinski, Torsten; Janek, Jürgen

    2015-06-16

    We describe the benefits of an online continuous flow differential electrochemical mass spectrometry (DEMS) method that allows for realistic battery cycling conditions. We provide a detailed description on the buildup and the role of the different components in the system. Special emphasis is given on the cell design. The retention time and response characteristics of the system are tested with the electrolysis of Li2O2. Finally, we show a practical application in which a Li-ion battery is examined. The value of long-term DEMS measurements for the proper evaluation of electrolyte decomposition is demonstrated by an experiment where a Li(1+x)Ni(0.5)Mn(0.3)Co(0.2)O2 (NMC 532)/graphite cell is cycled over 20 charge/discharge cycles. PMID:25965095

  14. An electric propulsion long term test facility

    NASA Technical Reports Server (NTRS)

    Trump, G.; James, E.; Vetrone, R.; Bechtel, R.

    1979-01-01

    An existing test facility was modified to provide for extended testing of multiple electric propulsion thruster subsystems. A program to document thruster subsystem characteristics as a function of time is currently in progress. The facility is capable of simultaneously operating three 2.7-kW, 30-cm mercury ion thrusters and their power processing units. Each thruster is installed via a separate air lock so that it can be extended into the 7m x 10m main chamber without violating vacuum integrity. The thrusters exhaust into a 3m x 5m frozen mercury target. An array of cryopanels collect sputtered target material. Power processor units are tested in an adjacent 1.5m x 2m vacuum chamber or accompanying forced convection enclosure. The thruster subsystems and the test facility are designed for automatic unattended operation with thruster operation computer controlled. Test data are recorded by a central data collection system scanning 200 channels of data a second every two minutes. Results of the Systems Demonstration Test, a short shakedown test of 500 hours, and facility performance during the first year of testing are presented.

  15. Long-Term Materials Test Program: materials exposure test plan

    SciTech Connect

    1981-12-01

    The Long Term Materials Test Program is designed to identify promising corrosion resistant materials for coal-fired gas turbine applications. Resistance of materials to long term accelerated corrosion will be determined through realistic PFB environmental exposure of candidate turbine materials for up to 14,000 hours. Selected materials also will be evaluated for their ability to withstand the combined erosive and corrosive aspects of the PFB effluent. A pressurized fluidized bed combustor facility has been constructed at the General Electric Coal Utilization Research Laboratory at Malta, New York. The 12-inch diameter combustor will burn high sulfur coal with moderate-to-high chlorine and alkali levels and utilize dolomite as the sulfur sorbent. Hot gas cleanup is achieved using three stages of cyclone separators. Downstream of the cylone separators, a low velocity test section (approx. 30 ft/s) capable of housing 180 pin specimens 1/4'' diameter has been installed to assess the corrosion resistance of the various materials at three different temperatures ranging from 1300 to 1600/sup 0/F. Following the low velocity test section is a high velocity test section consisting of four cascades of airfoil shaped specimens, six specimens per cascade. This high velocity test section is being used to evaluate the combined effects of erosion and corrosion on the degradation of gas turbine materials at gas velocities of 800 to 1400 ft/s. This report summarizes the materials selection and materials exposure test plan for the Long Term Materials Test.

  16. Long-term flow monitoring of submarine gas emanations

    NASA Astrophysics Data System (ADS)

    Spickenbom, K.; Faber, E.; Poggenburg, J.; Seeger, C.

    2009-04-01

    One of the Carbon Capture and Storage (CCS) strategies currently under study is the sequestration of CO2 in sub-seabed geological formations. Even after a thorough review of the geological setting, there is the possibility of leaks from the reservoirs. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. Technically, however, these systems are not limited to CO2 but can be used for monitoring of any free gas emission (bubbles) on the seafloor. The basic design of the gas flow sensor system was derived from former prototypes developed for monitoring CO2 and CH4 on mud volcanoes in Azerbaijan. This design was composed of a raft floating on the surface above the gas vent to collect the bubbles. Sensors for CO2 flux and concentration and electronics for data storage and transmission were mounted on the raft, together with battery-buffered solar panels for power supply. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, which is then guided above water level through a flexible tube. Besides some technical problems (condensed water in the tube, movement of the buoys due to waves leading to biased measurement of flow rates), this setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. To allow unattended long-term monitoring in a submarine environment, such a system has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system

  17. Evaluation of the Long-Term Performance of Titanate Ceramics for Immobilization of Excess Weapons Plutonium: Results from Pressurized Unsaturated Flow and Single Pass Flow-Through Testing

    SciTech Connect

    BP McGrail; HT Schaef; JP Icenhower; PF Martin; RD Orr; VL Legore

    1999-09-13

    This report summarizes our findings from pressurized unsaturated flow (PUF) and single-pass flow-through (SPFT) experiments to date. Results from the PUF test of a Pu-bearing ceramic with enclosing surrogate high-level waste glass show that the glass reacts rapidly to alteration products. Glass reaction causes variations in the solution pH in contact with the ceramic materials. We also document variable concentrations of Pu in solution, primarily in colloidal form, which appear to be related to secular variations in solution composition. The apparent dissolution rate of the ceramic waste form, based on Ba concentrations in the effluent, is estimated at {le} 10{sup {minus}5} g/(m{sup 2} {center_dot} d). Pu-bearing colloids were recovered in the size range of 0.2 to 2 {micro}m, but it is not clear that such entities would be transported in a system that is not advective-flow dominated. Results from SPFT experiments give information on the corrosion resistance of two surrogate Pu-ceramics (Ce-pyrochlore and Ce-zirconolite) at 90 C over a pH range of 2 to 12. The two ceramics were doped with minor quantities ({approximately}0.1 mass%) of MoO{sub 3}, so that concentrations of Mo in the effluent solution could be used to monitor the reaction behavior of the materials. The data obtained thus far from experiments with durations up to 150 d do not conclusively prove that the solid-aqueous solution systems have reached steady-state conditions. Therefore, the dissolution mechanism cannot be determined. Apparent dissolution rates of the two ceramic materials based on Ce, Gd, and Mo concentrations in the effluent solutions from the SPFT are nearly identical and vary between 1.1 to 8.5 x 10{sup {minus}4} g/(m{sup 2} {center_dot} d). In addition, the data reveal a slightly amphoteric dissolution behavior, with a minimum apparent rate at pH = 7 to 8, over the pH range examined. Results from two related ceramic samples suggest that radiation damage can have a measurable effect on

  18. Long-Term Learning, Achievement Tests, and Learner Centered Instruction

    ERIC Educational Resources Information Center

    Salinas, Moises F.; Kane-Johnson, Sarah E.; Vasil-Miller, Melissa A.

    2008-01-01

    The purpose of this study was to examine the effectiveness of achievement tests to measure long-term learning at the higher education level in traditional verses learner-centered classrooms. Volunteer instructors who use comprehensive achievement tests as an important component of their grading system were asked to complete an instrument that…

  19. The Long-Term Inflow and Structural Test Program

    SciTech Connect

    SUTHERLAND,HERBERT J; JONES,PERRY L.; NEAL,BYRON A.

    2000-10-17

    The Long-term Inflow and Structural Test (LIST) program is collecting long-term, continuous inflow and structural response data to characterize the extreme loads on wind turbines. A heavily instrumented Micon 65/13M turbine with SERI 8-m blades is being used as the first test turbine for this test program. This turbine and its two sister turbines are located in Bushland, TX a test site that exposes the turbines to a wind regime that is representative of a Great Plains commercial site. The turbines and their inflow are being characterized with 60 measurements: 34 to characterize the inflow, 19 to characterize structural response, and 7 to characterize the time-varying state of the turbine. The primary characterization of the inflow into the LIST turbine relies upon an array of five sonic anemometers. These three-axis anemometers are placed approximately 2-diameters upstream of the turbine in a pattern designed to describe the inflow. Primary characterization of the structural response of the turbine uses several sets of strain gauges to measure bending loads on the blades and the tower and two accelerometers to measure the motion of the nacelle. Data from the various instruments are sampled at a rate of 30 Hz using a newly developed data acquisition system that features a time-synchronized continuous data stream that is telemetered from the turbine rotor. The data, taken continuously, are automatically divided into 10-minute segments and archived for analysis. Preliminary data are presented to illustrate the operation of the turbine and the data acquisition and analysis system.

  20. 12 CFR 1266.3 - Purpose of long-term advances; Proxy test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Purpose of long-term advances; Proxy test. 1266... Advances to Members § 1266.3 Purpose of long-term advances; Proxy test. (a) A Bank shall make long-term... housing finance assets. (b)(1) Prior to approving an application for a long-term advance, a Bank...

  1. 12 CFR 1266.3 - Purpose of long-term advances; Proxy test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Purpose of long-term advances; Proxy test. 1266... Advances to Members § 1266.3 Purpose of long-term advances; Proxy test. (a) A Bank shall make long-term... housing finance assets. (b)(1) Prior to approving an application for a long-term advance, a Bank...

  2. Long Term Corrosion/Degradation Test Six Year Results

    SciTech Connect

    M. K. Adler Flitton; C. W. Bishop; M. E. Delwiche; T. S. Yoder

    2004-09-01

    The Subsurface Disposal Area (SDA) of the Radioactive Waste Management Complex (RWMC) located at the Idaho National Engineering and Environmental Laboratory (INEEL) contains neutron-activated metals from non-fuel, nuclear reactor core components. The Long-Term Corrosion/Degradation (LTCD) Test is designed to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements to the environment. The test is using two proven, industry-standard methods—direct corrosion testing using metal coupons, and monitored corrosion testing using electrical/resistance probes—to determine corrosion rates for various metal alloys generally representing the metals of interest buried at the SDA, including Type 304L stainless steel, Type 316L stainless steel, Inconel 718, Beryllium S200F, Aluminum 6061, Zircaloy-4, low-carbon steel, and Ferralium 255. In the direct testing, metal coupons are retrieved for corrosion evaluation after having been buried in SDA backfill soil and exposed to natural SDA environmental conditions for times ranging from one year to as many as 32 years, depending on research needs and funding availability. In the monitored testing, electrical/resistance probes buried in SDA backfill soil will provide corrosion data for the duration of the test or until the probes fail. This report provides an update describing the current status of the test and documents results to date. Data from the one-year and three-year results are also included, for comparison and evaluation of trends. In the six-year results, most metals being tested showed extremely low measurable rates of general corrosion. For Type 304L stainless steel, Type 316L stainless steel, Inconel 718, and Ferralium 255, corrosion rates fell in the range of “no reportable” to 0.0002 mils per year (MPY). Corrosion rates for Zircaloy-4 ranged from no measurable corrosion to 0.0001 MPY. These rates are two orders of magnitude lower than those specified in

  3. PROTEC TM TEAR-OFFS: RESULTS OF LONG TERM TESTING

    SciTech Connect

    Peeler, D

    2008-07-24

    damage that would result from acid etching, base damage (as a result of a sludge spill or splatter), gamma radiation damage, and/or accidental scratching (due to manipulator/tool contact). Although identified as a potential solution, the Phase 1 testing was relatively short-term with exposure times up to 1-2 months for the acid and gamma radiation tests. Phase 2 testing included longer exposure times for the acid resistance (up to 456 days) and gamma radiation exposure (700 days with a cumulative gamma dose of {approx}3.1 x 10{sup 5} rad) assessments. The tear-off system continued to perform well in these longer-term acid resistance testing and gamma exposure conditions. Complete removal of the tear-offs after these long-term exposure times indicate that not only could visual clarity be restored but the mechanical integrity could be retained. The results also provided insight into the ability of the ProTec tear-off system to withstand the chemical and physical abuses expected in off-normal shielded cells operations. The conceptual erasing of scratches or marks by excessive manipulator abuse was demonstrated in the SRNL Shielded Cells mock-up facility through the removal of the outer layer tear-off with manipulators. In addition, the Phase 2 testing included an in-situ assessment of a prototype tear-off system in the DWPF Sampling Cells where the system was exposed to actual field conditions including radioactive sources, acidic and basic environments, dusting, and chemical cleaning solutions over a 5-6 month period. DWPF personnel were extremely satisfied with the performance (including the successful removal of 3 layers with manipulators) of the ProTec tear-off system under actual field conditions. The successful removal of the outer layer tear-offs with the manipulator, using tabs not specifically designed for remote operations, demonstrates that the system is 'manipulator-friendly' and could be implemented in a remote environment. The ability to remove the outer layer

  4. The inbuilt long-term unfeasibility of environmental flows when disregarding riparian vegetation requirements

    NASA Astrophysics Data System (ADS)

    Rivaes, R.; Boavida, I.; Santos, J. M.; Pinheiro, A. N.; Ferreira, M. T.

    2015-10-01

    Environmental flows remain biased towards the traditional fish biological group and ignore the inter-annual flow variability that rules longer species life cycles, thus disregarding the long-term perspective of the riverine ecosystem. Incorporating riparian vegetation requirements into environmental flows could bring an important contribute to fill in this gap. The long-term after-effects of this shortcoming on the biological communities downstream of dams were never estimated before. We address this concern by evaluating the effects of environmental flow regimes disregarding riparian vegetation in the long-term perspective of the fluvial ecosystem. To achieve that purpose, the riparian vegetation evolution was modeled considering its structural response to a decade of different environmental flows, and the fish habitat availability was assessed for each of the resulting riparian habitat scenarios. We demonstrate that fish habitat availability changes accordingly to the long-term structural adjustments that riparian habitat endure following river regulation. Environmental flow regimes considering only aquatic biota become obsolete in few years due to the change of the habitat premises in which they were based on and, therefore, are unsustainable in the long run. Therefore, considering riparian vegetation requirements on environmental flows is mandatory to assure the effectiveness of those in the long-term perspective of the fluvial ecosystem.

  5. Long-term Monitoring Plan for the Central Nevada Test Area

    SciTech Connect

    A. Hassan

    2003-09-02

    The groundwater flow and transport model of the Faultless underground nuclear test conducted at the Central Nevada Test Area (CNTA) was accepted by the state regulator and the environmental remediation efforts at the site have progressed to the stages of model validation and long-term monitoring design. This report discusses the long-term monitoring strategy developed for CNTA. Subsurface monitoring is an expensive and time-consuming process, and the design approach should be based on a solid foundation. As such, a thorough literature review of monitoring network design is first presented. Monitoring well networks can be designed for a number of objectives including aquifer characterization, parameter estimation, compliance monitoring, detection monitoring, ambient monitoring, and research monitoring, to name a few. Design methodologies also range from simple hydrogeologic intuition-based tools to sophisticated statistical- and optimization-based tools. When designing the long-term monitoring well network for CNTA, a number of issues are carefully considered. These are the uncertainty associated with the subsurface environment and its implication for monitoring design, the cost associated with monitoring well installation and operation, the design criteria that should be used to select well locations, and the potential conflict between different objectives such as early detection versus impracticality of placing wells in the vicinity of the test cavity. Given these considerations and the literature review of monitoring design studies, a multi-staged approach for development of the long-term monitoring well network for CNTA is proposed. This multi-staged approach will proceed in parallel with the validation efforts for the groundwater flow and transport model of CNTA. Two main stages are identified as necessary for the development of the final long-term monitoring well network for the site. The first stage is to use hydrogeologic expertise combined with model

  6. Cerebral blood flow differences between long-term meditators and non-meditators.

    PubMed

    Newberg, Andrew B; Wintering, Nancy; Waldman, Mark R; Amen, Daniel; Khalsa, Dharma S; Alavi, Abass

    2010-12-01

    We have studied a number of long-term meditators in previous studies. The purpose of this study was to determine if there are differences in baseline brain function of experienced meditators compared to non-meditators. All subjects were recruited as part of an ongoing study of different meditation practices. We evaluated 12 advanced meditators and 14 non-meditators with cerebral blood flow (CBF) SPECT imaging at rest. Images were analyzed with both region of interest and statistical parametric mapping. The CBF of long-term meditators was significantly higher (p<.05) compared to non-meditators in the prefrontal cortex, parietal cortex, thalamus, putamen, caudate, and midbrain. There was also a significant difference in the thalamic laterality with long-term meditators having greater asymmetry. The observed changes associated with long-term meditation appear in structures that underlie the attention network and also those that relate to emotion and autonomic function. PMID:20570534

  7. Operational summary of an electric propulsion long term test facility

    NASA Technical Reports Server (NTRS)

    Trump, G. E.; James, E. L.; Bechtel, R. T.

    1982-01-01

    An automated test facility capable of simultaneously operating three 2.5 kW, 30-cm mercury ion thrusters and their power processors is described, along with a test program conducted for the documentation of thruster characteristics as a function of time. Facility controls are analog, with full redundancy, so that in the event of malfunction the facility automaticcally activates a backup mode and notifies an operator. Test data are recorded by a central data collection system and processed as daily averages. The facility has operated continuously for a period of 37 months, over which nine mercury ion thrusters and four power processor units accumulated a total of over 14,500 hours of thruster operating time.

  8. Long term tests of a SNAP-19 thermoelectric generator.

    NASA Technical Reports Server (NTRS)

    Rouklove, P.; Truscello, V.

    1972-01-01

    Results of tests performed on a SNAP 19 thermoelectric generator, SN-20. The SN-20 generator was tested for approximately 37,000 hours using electrical heating to simulate the heat released by isotope decay. After 27,000 hours of operation the output power from the generator decreased to approximately 1/3 of the beginning of life value while the internal resistance increased by a factor of 5. Analysis of the test results, confirmed by preliminary metallographic examination, indicated that the output power degradation was the result of excessive sublimation of the thermoelectric material and loss of the hot junction bond due to the depletion of the internal cover gas. This also resulted in excessive junction temperatures. Comparison is made with the behavior observed from the two flight generators and a tentative conclusion is advanced as to the reason for their failure.

  9. Long term testing of peanut oil in engines

    SciTech Connect

    Goodrum, J.W.

    1985-01-01

    Durability tests of engines using crude peanut oil blended with no. 2 diesel were conducted, using the E.M.A. screening procedure. Direct and indirect injection designs were operated on 20:80 and 80:28 fuel blends. Time-dependent exhaust temperature changes, mechanical wear, and crank-case oil viscosity changes were evaluated.

  10. Effect of Long-term Smoking on Whole-mouth Salivary Flow Rate and Oral Health

    PubMed Central

    Rad, Maryam; Kakoie, Shahla; Niliye Brojeni, Fateme; Pourdamghan, Nasim

    2010-01-01

    Background and aims Change in the resting whole-mouth salivary flow rate (SFR) plays a significant role in patho-genesis of various oral conditions. Factors such as smoking may affect SFR as well as the oral and dental health. The primary purpose of this study was to determine the effect of smoking on SFR, and oral and dental health. Materials and methods One-hundred smokers and 100 non-tobacco users were selected as case and control groups, respectively. A questionnaire was used to collect the demographic data and smoking habits. A previously used questionnaire about dry mouth was also employed. Then, after a careful oral examination, subjects’ whole saliva was collected in the resting condition. Data was analyzed by chi-square test using SPSS 15. Results The mean (±SD) salivary flow rate were 0.38 (± 0.13) ml/min in smokers and 0.56 (± 0.16) ml/min in non-smokers. The difference was statistically significant (P=0.00001). Also, 39% of smokers and 12% of non-smokers reported experiencing at least one xerostomia symptom, with statistically significant difference between groups (p=0.0001). Oral lesions including cervical caries, gingivitis, tooth mobility, calculus and halitosis were significantly higher in smokers. Conclusion Our findings indicated that long-term smoking would significantly reduce SFR and increase oral and dental disorders associated with dry mouth, especially cervical caries, gingivitis, tooth mobility, calculus, and halitosis. PMID:23346336

  11. Long-term degradation of dilute polyacrylamide solutions in turbulent pipe flow

    SciTech Connect

    Choi, U.S.; Kasza, K.E.

    1989-05-01

    The long-term degradation behavior of 200 wppM polyacrylamide solution was studied experimentally in a closed recirculatory flow loop at temperatures of 7.2, 25 and 87.8/degree/C. The degradation behavior was found to be strongly dependent on temperature. The results indicate that, with flow shear similar to that encountered in practical DHC pipe flow, polyacrylamide solutions are highly effective and have a reasonable lifetime at chilled water temperature of 7.2/degree/C. 9 refs., 4 figs.

  12. Report on the Long-Term Testing of the Highland V880 DDG

    SciTech Connect

    Martin, A.J.

    2000-05-19

    A testing facility for evaluating ITS hardware components has been established in Trailer 3907. In accordance with our acceptance testing of the Highland V880 digital delay generators (DDG), software has been written to allow long-term testing to be performed on the four V880 prototypes (NIF-5000375). Problems and discrepancies discovered through long-term testing have been documented, and a summary of the problems found and the corrective actions taken are presented in this report. For more background information about the National Ignition Facility and the Integrated Timing System, see UCRL-JC-135036.

  13. Long-term performance of landfill covers - results of lysimeter test fields in Bavaria (Germany).

    PubMed

    Henken-Mellies, Wolf-Ulrich; Schweizer, Andreas

    2011-01-01

    A comprehensive study was conducted to examine the performance and possible changes in the effectiveness of landfill surface covers. Three different profiles of mineral landfill caps were examined. The results of precipitation and flow measurements show distinct seasonal differences which are typical for middle-European climatic conditions. In the case of the simple landfill cap design consisting of a thick layer of loamy sand, approximately 100-200 L m(-2) of annual seepage into the landfill body occurs during winter season. The three-layer systems of the two other test fields performed much better. Most of the water which percolated through the top soil profile drained sideways in the drainage layer. Only 1-3% of precipitation percolated through the sealing layer. The long-term effectiveness of the mineral sealing layer depended on the ability of the top soil layer to protect it from critical loss of soil water/critical increase of suction. In dry summers there was even a loss in soil water content at the base of the 2.0 m thick soil cover. The results of this study demonstrate the importance of the long-term aspect when assessing the effectiveness of landfill covers: The hydraulic conductivity at the time of construction gives only an initial (minimum) value. The hydraulic conductivity of the compacted clay layer or of the geosynthetic clay liner may increase substantially, if there is no long-lasting protection against desiccation (by a thick soil cover or by a geomembrane). This has to be taken into account in landfill cover design. PMID:20937619

  14. Long-term Monitoring Plan for the Central Nevada Test Area

    SciTech Connect

    Hassan, Ahmed E

    2004-01-01

    This report discusses the long-term monitoring strategy developed for the Central Nevada Test Area (CNTA), where the Faultless underground nuclear test was conducted. It includes a thorough literature review of monitoring well network design. A multi-staged approach for development of the long-term monitoring well network for CNTA is proposed, incorporating a number of issues, including uncertainty of the subsurface environment, cost, selection of well locations, etc. The first stage is to use hydrogeologic expertise combined with model simulations and probability based approaches to select the first set of monitoring wells. The second stage will be based on an optimum design methodology that uses a suitable statistical approach, combined with an optimization approach, to augment the initial set of wells and develop the final long-term monitoring network.

  15. Long term shift of low flows predictors in small lowland catchments of Northeast Germany

    NASA Astrophysics Data System (ADS)

    Thomas, Björn; Lischeid, Gunnar; Steidl, Jörg; Dietrich, Ottfried

    2015-02-01

    Runoff, especially during summer months, and low flows have decreased in Central and Eastern Europe during the last decades. A detailed knowledge on predictors and dependencies between meteorological forcing, catchment properties and low flow is necessary to optimize regional adaption strategies to sustain minimum runoff. The objective of this study is to identify low flow predictors for 16 small catchments in Northeast Germany and their long-term shifts between 1965 and 2006. Non-linear regression models (support vector machine regression) were calibrated to iteratively select the most powerful low flow predictors regarding annual 30-day minimum flow (AM30). The data set consists of standardized precipitation (SPI) and potential evapotranspiration (SpETI) indices on different time scales and lag times. The potential evapotranspiration of the previous 48 and 3 months, as well as the precipitation of the previous 3 months and last year were the most relevant predictors for AM30. Pearson correlation (r2) of the final model is 0.49 and if for every year the results for all catchments are averaged r2 increases to 0.80 because extremes are smoothing out. Evapotranspiration was the most important low flow predictor for the study period. However, distinct long-term shifts in the predictive power of variables became apparent. The potential evapotranspiration of the previous 48 months explained most of the variance, but its relevance decreased during the last decades. The importance of precipitation variables increased with time. Model performance was higher at catchments with a more damped discharge behavior. The results indicate changes in the relevant processes or flow paths generating low flows. The identified predictors, temporal patterns and patterns between catchments will support the development of low flow monitoring systems and determine those catchments where adaption measures should aim more at increasing groundwater recharge.

  16. Role of debris flows in long-term landscape denudation in the central Appalachians of Virginia

    NASA Astrophysics Data System (ADS)

    Eaton, Louis Scott; Morgan, Benjamin A.; Kochel, R. Craig; Howard, Alan D.

    2003-04-01

    Four major storms that triggered debris flows in the Virginia West Virginia Appalachians provide new insights into the role of high-magnitude, low-frequency floods in long-term denudation and landscape evolution in mountainous terrain. Storm denudation in the Blue Ridge Mountain drainage basins is approximately an order of magnitude greater compared to basins located in the mountains of the Valley and Ridge province. This difference is probably the result of higher storm rainfall from the Blue Ridge storms. Radiocarbon dating of debris-flow deposits in the Blue Ridge indicates a debris-flow return interval of not more than 2 4 k.y. in mountainous river basins. This finding, combined with measurements of basin denudation, suggests that approximately half of the long-term denudation from mechanical load occurs episodically by debris-flow processes. Although floods of moderate magnitude are largely responsible for mobilizing sediment in low-gradient streams, our data suggest that high-magnitude, low-frequency events are the most significant component in delivering coarse-grained regolith from mountainous hollows and channels to the lowland floodplains.

  17. Providing Extrinsic Reward for Test Performance Undermines Long-Term Memory Acquisition

    PubMed Central

    Kuhbandner, Christof; Aslan, Alp; Emmerdinger, Kathrin; Murayama, Kou

    2016-01-01

    Based on numerous studies showing that testing studied material can improve long-term retention more than restudying the same material, it is often suggested that the number of tests in education should be increased to enhance knowledge acquisition. However, testing in real-life educational settings often entails a high degree of extrinsic motivation of learners due to the common practice of placing important consequences on the outcome of a test. Such an effect on the motivation of learners may undermine the beneficial effects of testing on long-term memory because it has been shown that extrinsic motivation can reduce the quality of learning. To examine this issue, participants learned foreign language vocabulary words, followed by an immediate test in which one-third of the words were tested and one-third restudied. To manipulate extrinsic motivation during immediate testing, participants received either monetary reward contingent on test performance or no reward. After 1 week, memory for all words was tested. In the immediate test, reward reduced correct recall and increased commission errors, indicating that reward reduced the number of items that can benefit from successful retrieval. The results in the delayed test revealed that reward additionally reduced the gain received from successful retrieval because memory for initially successfully retrieved words was lower in the reward condition. However, testing was still more effective than restudying under reward conditions because reward undermined long-term memory for concurrently restudied material as well. These findings indicate that providing performance–contingent reward in a test can undermine long-term knowledge acquisition. PMID:26869978

  18. Providing Extrinsic Reward for Test Performance Undermines Long-Term Memory Acquisition.

    PubMed

    Kuhbandner, Christof; Aslan, Alp; Emmerdinger, Kathrin; Murayama, Kou

    2016-01-01

    Based on numerous studies showing that testing studied material can improve long-term retention more than restudying the same material, it is often suggested that the number of tests in education should be increased to enhance knowledge acquisition. However, testing in real-life educational settings often entails a high degree of extrinsic motivation of learners due to the common practice of placing important consequences on the outcome of a test. Such an effect on the motivation of learners may undermine the beneficial effects of testing on long-term memory because it has been shown that extrinsic motivation can reduce the quality of learning. To examine this issue, participants learned foreign language vocabulary words, followed by an immediate test in which one-third of the words were tested and one-third restudied. To manipulate extrinsic motivation during immediate testing, participants received either monetary reward contingent on test performance or no reward. After 1 week, memory for all words was tested. In the immediate test, reward reduced correct recall and increased commission errors, indicating that reward reduced the number of items that can benefit from successful retrieval. The results in the delayed test revealed that reward additionally reduced the gain received from successful retrieval because memory for initially successfully retrieved words was lower in the reward condition. However, testing was still more effective than restudying under reward conditions because reward undermined long-term memory for concurrently restudied material as well. These findings indicate that providing performance-contingent reward in a test can undermine long-term knowledge acquisition. PMID:26869978

  19. Data acquisition for low-temperature geothermal well tests and long-term monitoring

    SciTech Connect

    Lienau, P.J.

    1992-09-01

    Groundwater monitoring is an essential part of the development of a low-temperature geothermal field for production and injection wells. State water resource and environmental departments are requiring both geothermal well testing and long-term monitoring as a part of the permitting process for geothermal developments. This report covers water-level measurement methods, instruments used for well testing, geochemical sampling, examples of data acquisition and regulatory mandates on groundwater monitoring.

  20. Data acquisition for low-temperature geothermal well tests and long-term monitoring. Final report

    SciTech Connect

    Lienau, P.J.

    1992-09-01

    Groundwater monitoring is an essential part of the development of a low-temperature geothermal field for production and injection wells. State water resource and environmental departments are requiring both geothermal well testing and long-term monitoring as a part of the permitting process for geothermal developments. This report covers water-level measurement methods, instruments used for well testing, geochemical sampling, examples of data acquisition and regulatory mandates on groundwater monitoring.

  1. Long-Term Degradation Testing of High-Temperature Electrolytic Cells

    SciTech Connect

    C.M. Stoots; J.E. O'Brien; J.S. Herring; G.K. Housley; D.G. Milobar; M.S. Sohal

    2009-08-01

    The Idaho National Laboratory (INL) has been researching the application of solid-oxide electrolysis cell for large-scale hydrogen production from steam over a temperature range of 800 to 900ºC. The INL has been testing various solid oxide cell designs to characterize their electrolytic performance operating in the electrolysis mode for hydrogen production. Some results presented in this report were obtained from cells, with an active area of 16 cm2 per cell. The electrolysis cells are electrode-supported, with ~10 µm thick yttria-stabilized zirconia (YSZ) electrolytes, ~1400 µm thick nickel-YSZ steam-hydrogen electrodes, and manganite (LSM) air-oxygen electrodes. The experiments were performed over a range of steam inlet mole fractions (0.1 to 0.6), gas flow rates, and current densities (0 to 0.6 A/cm2). Steam consumption rates associated with electrolysis were measured directly using inlet and outlet dewpoint instrumentation. On a molar basis, the steam consumption rate is equal to the hydrogen production rate. Cell performance was evaluated by performing DC potential sweeps at 800, 850, and 900°C. The voltage-current characteristics are presented, along with values of area-specific resistance as a function of current density. Long-term cell performance is also assessed to evaluate cell degradation. Details of the custom single-cell test apparatus developed for these experiments are also presented. NASA, in conjunction with the University of Toledo, has developed a new cell concept with the goals of reduced weight and high power density. This report presents results of the INL's testing of this new solid oxide cell design as an electrolyzer. Gas composition, operating voltage, and other parameters were varied during testing. Results to date show the NASA cell to be a promising design for both high power-to-weight fuel cell and electrolyzer applications.

  2. Evaluation of Long-Term Migration Testing from Can Coatings into Food Simulants: Polyester Coatings.

    PubMed

    Paseiro-Cerrato, Rafael; Noonan, Gregory O; Begley, Timothy H

    2016-03-23

    FDA guidance for food contact substances recommends that for food packaging intended for use at sterilized, high temperature processed, or retorted conditions, a migration test with a retort step at 121 °C for 2 h followed by a 10 day migration test at 40 °C should be performed. These conditions are in intended to simulate processing and long-term storage. However, can coatings may be in contact with food for years, and there are very few data evaluating if this short-term testing accurately simulates migration over extended time periods. A long-term migration test at 40 °C with retorted and non-retorted polyester cans using several food simulants (water, 3% acetic acid, 10% ethanol, 50% ethanol, and isooctane) was conducted to verify whether traditional migration testing protocols accurately predict migration from food contact materials used for extended time periods. Time points were from 1 day to 515 days. HPLC-MS/MS was used to analyze polyester monomers, and oligomer migration was monitored using HPLC-DAD/CAD and HPLC-MS. Concentrations of monomers and oligomers increased during the migration experiments, especially in ethanol food simulants. The data suggest that current FDA migration protocols may need to be modified to address changes in migrants as a result of long-term storage conditions. PMID:26917426

  3. Long-term performance of subsurface-flow constructed wetlands treating Cd wastewater.

    PubMed

    Visesmanee, Varangkana; Polprasert, Chongrak; Parkpian, Preeda

    2008-06-01

    This study was conducted to investigate the long-term performance of subsurface-flow constructed wetland (SFCW) units treating a wastewater containing cadmium (Cd). The hydraulic retention time (HRT) was found to have significant effects on the SFCW performance, especially on Cd removal. During the 320 days of Cd feeding, the HRTs of 1, 3, 5 and 8 days resulted in the Cd removal efficiencies of 50, 90, 99 and 99%, respectively. The actual Cd breakthrough times in the SFCW effluent were found to be longer than the theoretical values calculated from the maximum adsorption capacities only, especially at the HRTs longer than 1 day, and were dependent on the operating HRT and Cd loading. Other mechanisms such as filtration, sedimentation and plant uptake were also responsible for Cd removal in the SFCW beds. The extents of Cd plant uptake were 21 and 6% of the Cd inputs for the SFCW units operating at the HRTs of 3 and 1 days, respectively. Based on Cd mass balance and fractionation analysis, the SFCW media were found to be most effective in Cd removal through adsorption of the residual and Fe/Mn oxide bound fractions. The results of this long-term study re-affirmed the necessity to determine actual breakthrough times of Cd or other heavy metals in the SFCW effluent which are dependent on HRT and Cd loading and are usually longer than the theoretical values calculated from the maximum adsorption capacity only. PMID:18444079

  4. A long-term national-scale hydrological simulation of river flows across Great Britain

    NASA Astrophysics Data System (ADS)

    Rudd, Alison; Bell, Victoria; Kay, Alison; Davies, Helen

    2016-04-01

    The Centre for Ecology and Hydrology's national-scale hydrological model, Grid-to-Grid, can be used to estimate river flows and soil moisture across Great Britain. It is used operationally at the flood forecasting centre and there have been a number of studies on floods and climate change using this model, however to date, low flows and droughts have been comparatively neglected. The launch of a five-year NERC-funded interdisciplinary research programme "UK Droughts and Water Scarcity" is allowing us to address this. Our work on one of these projects, MaRIUS (Managing the Risks, Impacts and Uncertainties of droughts and water Scarcity), uses the model to identify drought periods. The model is driven by a new long-term (1890 - 2012) precipitation dataset (CEH-GEAR) and estimates of potential evaporation. Model performance is assessed against observed river flows for both high and low flows. Gridded time series of monthly mean river flow and soil moisture from the model have been analysed to identify historic hydrological droughts across Great Britain using concepts such as severity and duration. We also investigate how drought occurrence and severity have changed over the last 100 years and identify regions that have been particularly susceptible to drought.

  5. Evaluation of long-term gas hydrate production testing locations on the Alaska north slope

    USGS Publications Warehouse

    Collett, T.S.; Boswell, R.; Lee, M.W.; Anderson, B.J.; Rose, K.; Lewis, K.A.

    2011-01-01

    The results of short duration formation tests in northern Alaska and Canada have further documented the energy resource potential of gas hydrates and justified the need for long-term gas hydrate production testing. Additional data acquisition and long-term production testing could improve the understanding of the response of naturally-occurring gas hydrate to depressurization-induced or thermal-, chemical-, and/or mechanical-stimulated dissociation of gas hydrate into producible gas. The Eileen gas hydrate accumulation located in the Greater Prudhoe Bay area in northern Alaska has become a focal point for gas hydrate geologic and production studies. BP Exploration (Alaska) Incorporated and ConocoPhillips have each established research partnerships with U.S. Department of Energy to assess the production potential of gas hydrates in northern Alaska. A critical goal of these efforts is to identify the most suitable site for production testing. A total of seven potential locations in the Prudhoe Bay, Kuparuk, and Milne Point production units were identified and assessed relative to their suitability as a long-term gas hydrate production test site. The test site assessment criteria included the analysis of the geologic risk associated with encountering reservoirs for gas hydrate testing. The site selection process also dealt with the assessment of the operational/logistical risk associated with each of the potential test sites. From this review, a site in the Prudhoe Bay production unit was determined to be the best location for extended gas hydrate production testing. The work presented in this report identifies the key features of the potential test site in the Greater Prudhoe Bay area, and provides new information on the nature of gas hydrate occurrence and potential impact of production testing on existing infrastructure at the most favorable sites. These data were obtained from well log analysis, geological correlation and mapping, and numerical simulation

  6. Evaluation of long-term gas hydrate production testing locations on the Alaska North Slope

    USGS Publications Warehouse

    Collett, Timothy; Boswell, Ray; Lee, Myung W.; Anderson, Brian J.; Rose, Kelly K.; Lewis, Kristen A.

    2011-01-01

    The results of short duration formation tests in northern Alaska and Canada have further documented the energy resource potential of gas hydrates and justified the need for long-term gas hydrate production testing. Additional data acquisition and long-term production testing could improve the understanding of the response of naturally-occurring gas hydrate to depressurization-induced or thermal-, chemical-, and/or mechanical-stimulated dissociation of gas hydrate into producible gas. The Eileen gas hydrate accumulation located in the Greater Prudhoe Bay area in northern Alaska has become a focal point for gas hydrate geologic and production studies. BP Exploration (Alaska) Incorporated and ConocoPhillips have each established research partnerships with U.S. Department of Energy to assess the production potential of gas hydrates in northern Alaska. A critical goal of these efforts is to identify the most suitable site for production testing. A total of seven potential locations in the Prudhoe Bay, Kuparuk, and Milne Point production units were identified and assessed relative to their suitability as a long-term gas hydrate production test site. The test site assessment criteria included the analysis of the geologic risk associated with encountering reservoirs for gas hydrate testing. The site selection process also dealt with the assessment of the operational/logistical risk associated with each of the potential test sites. From this review, a site in the Prudhoe Bay production unit was determined to be the best location for extended gas hydrate production testing. The work presented in this report identifies the key features of the potential test site in the Greater Prudhoe Bay area, and provides new information on the nature of gas hydrate occurrence and potential impact of production testing on existing infrastructure at the most favorable sites. These data were obtained from well log analysis, geological correlation and mapping, and numerical simulation.

  7. Evaluation of long-term gas hydrate production testing locations on the Alaska North Slope

    USGS Publications Warehouse

    Collett, Timothy S.; Boswell, Ray; Lee, Myung W.; Anderson, Brian J.; Rose, Kelly K.; Lewis, Kristen A.

    2012-01-01

    The results of short-duration formation tests in northern Alaska and Canada have further documented the energy-resource potential of gas hydrates and have justified the need for long-term gas-hydrate-production testing. Additional data acquisition and long-term production testing could improve the understanding of the response of naturally occurring gas hydrate to depressurization-induced or thermal-, chemical-, or mechanical-stimulated dissociation of gas hydrate into producible gas. The Eileen gashydrate accumulation located in the Greater Prudhoe Bay area in northern Alaska has become a focal point for gas-hydrate geologic and production studies. BP Exploration (Alaska) Incorporated and ConocoPhillips have each established research partnerships with the US Department of Energy to assess the production potential of gas hydrates in northern Alaska. A critical goal of these efforts is to identify the most suitable site for production testing. A total of seven potential locations in the Prudhoe Bay, Kuparuk River, and Milne Point production units were identified and assessed relative to their suitability as a long-term gas-hydrate-production test sites. The test-site-assessment criteria included the analysis of the geologic risk associated with encountering reservoirs for gas-hydrate testing. The site-selection process also dealt with the assessment of the operational/logistical risk associated with each of the potential test sites. From this review, a site in the Prudhoe Bay production unit was determined to be the best location for extended gas-hydrate-production testing. The work presented in this report identifies the key features of the potential test site in the Greater Prudhoe Bay area and provides new information on the nature of gas-hydrate occurrence and the potential impact of production testing on existing infrastructure at the most favorable sites. These data were obtained from well-log analysis, geological correlation and mapping, and numerical

  8. Patient empowerment in long-term conditions: development and preliminary testing of a new measure

    PubMed Central

    2013-01-01

    Background Patient empowerment is viewed by policy makers and health care practitioners as a mechanism to help patients with long-term conditions better manage their health and achieve better outcomes. However, assessing the role of empowerment is dependent on effective measures of empowerment. Although many measures of empowerment exist, no measure has been developed specifically for patients with long-term conditions in the primary care setting. This study presents preliminary data on the development and validation of such a measure. Methods We conducted two empirical studies. Study one was an interview study to understand empowerment from the perspective of patients living with long-term conditions. Qualitative analysis identified dimensions of empowerment, and the qualitative data were used to generate items relating to these dimensions. Study two was a cross-sectional postal study involving patients with different types of long-term conditions recruited from general practices. The survey was conducted to test and validate our new measure of empowerment. Factor analysis and regression were performed to test scale structure, internal consistency and construct validity. Results Sixteen predominately elderly patients with different types of long-term conditions described empowerment in terms of 5 dimensions (identity, knowledge and understanding, personal control, personal decision-making, and enabling other patients). One hundred and ninety seven survey responses were received from mainly older white females, with relatively low levels of formal education, with the majority retired from paid work. Almost half of the sample reported cardiovascular, joint or diabetes long-term conditions. Factor analysis identified a three factor solution (positive attitude and sense of control, knowledge and confidence in decision making and enabling others), although the structure lacked clarity. A total empowerment score across all items showed acceptable levels of internal

  9. Standardizing flow cytometric assays in long-term population-based studies

    NASA Astrophysics Data System (ADS)

    Melzer, Susanne; Bocsi, Jozsef; Tárnok, Attila

    2015-03-01

    Quantification of leukocyte subpopulations and characterization of antigen-expression pattern on the cellular surface can play an important role in diagnostics. The state of cellular immunology on the single-cell level was analyzed by polychromatic flow cytometry in a recent comparative study within the average Leipzig population (LIFE - Leipzig Research Centre for Civilization Diseases). Data of 1699 subjects were recorded over a long-time period of three years (in a total of 1126 days). To ensure compatibility of such huge data sets, quality-controls on many levels (stability of instrumentation, low intra-laboratory variance and reader independent data analysis) are essential. The LIFE study aims to analyze various cytometric pattern to reveal the relationship between the life-style, the environmental effects and the individual health. We therefore present here a multi-step quality control procedure for long-term comparative studies.

  10. Long-term affects of experimental flows on riverine biota below a reservoir

    NASA Astrophysics Data System (ADS)

    Robinson, Chris; Ortlepp, Johannes

    2010-05-01

    Large dams have altered the flow regime of most rivers on the globe with consequent effects on riverine biota. Experimental flows (multiple floods per year) have been used on the regulated Spöl River below Livigno Reservoir for over 9 years to enhance the ecological condition of the river. The flow program has improved the brown trout fishery in the river as indicated by an increased number of redds. Floods have reset periphyton assemblages from a moss-dominated streambed to one dominated by diatoms and patches of filamentous algae. Zoobenthic assemblages have shown dramatic shifts in benthic structure in line with predictions from altered state models. Ecosystem regime shifts have been characterized with increases in parameter variances followed by periods of stable states. The system appears to be entering a second zoobenthic regime shift after year 8, perhaps in response to biotic interactions due to changes in the fishery. The response patterns clearly show that a long-term perspective must be in place when assessing biotic responses to changes in physical habitat properties resulting from flow experiments.

  11. Long-term continuous-flow left ventricular assist devices (LVAD) as bridge to heart transplantation

    PubMed Central

    Pozzi, Matteo; Giraud, Raphaël; Tozzi, Piergiorgio; Bendjelid, Karim; Robin, Jacques; Meyer, Philippe; Obadia, Jean François

    2015-01-01

    Heart transplantation (HTx) is the treatment of choice for end-stage heart failure but the limited availability of heart’s donors still represents a major issue. So long-term mechanical circulatory support (MCS) has been proposed as an alternative treatment option to assist patients scheduled on HTx waiting list bridging them for a variable time period to cardiac transplantation—the so-called bridge-to-transplantation (BTT) strategy. Nowadays approximately 90% of patients being considered for MCS receive a left ventricular assist device (LVAD). In fact, LVAD experienced several improvements in the last decade and the predominance of continuous-flow over pulsatile-flow technology has been evident since 2008. The aim of the present report is to give an overview of continuous-flow LVAD utilization in the specific setting of the BTT strategy taking into consideration the most representative articles of the scientific literature and focusing the attention on the evolution, clinical outcomes, relevant implications on the HTx strategy and future perspectives of the continuous-flow LVAD technology. PMID:25922736

  12. Test Plan for Long-Term Operation of a Ten-Cell High Temperature Electrolysis Stack

    SciTech Connect

    James E. O'Brien; Carl M. Stoots; J. Stephen Herring

    2008-07-01

    This document defines a test plan for a long-term (2500 Hour) test of a ten-cell high-temperature electrolysis stack to be performed at INL during FY09 under the Nuclear Hydrogen Initiative. This test was originally planned for FY08, but was removed from our work scope as a result of the severe budget cuts in the FY08 NHI Program. The purpose of this test is to evaluate stack performance degradation over a relatively long time period and to attempt to identify some of the degradation mechanisms via post-test examination. This test will be performed using a planar ten-cell Ceramatec stack, with each cell having dimensions of 10 cm × 10 cm. The specific makeup of the stack will be based on the results of a series of shorter duration ten-cell stack tests being performed during FY08, funded by NGNP. This series of tests was aimed at evaluating stack performance with different interconnect materials and coatings and with or without brazed edge rails. The best performing stack from the FY08 series, in which five different interconnect/coating/edge rail combinations were tested, will be selected for the FY09 long-term test described herein.

  13. Long-term psychosocial and behavioral adjustment in individuals receiving genetic test results in Lynch syndrome.

    PubMed

    Esplen, M J; Wong, J; Aronson, M; Butler, K; Rothenmund, H; Semotiuk, K; Madlensky, L; Way, C; Dicks, E; Green, J; Gallinger, S

    2015-06-01

    A cross-sectional study of 155 participants who underwent genetic testing for Lynch syndrome (LS) examined long-term psychosocial and behavioral outcomes. Participants completed standardized measures of perceived risk, psychosocial functioning, knowledge, and a questionnaire of screening activities. Participants were on average 47.3 years and had undergone testing a mean of 5.5 years prior. Eighty four (54%) tested positive for a LS mutation and 71 (46%) negative. For unaffected carriers, perceived lifetime risk of colorectal cancer was 68%, and surprisingly, 40% among those testing negative. Most individuals demonstrated normative levels of psychosocial functioning. However, 25% of those testing negative had moderate depressive symptoms, as measured by the Center for Epidemiologic Studies for Depression Scale, and 31% elevated state anxiety on the State-Trait Anxiety Inventory. Being female and a stronger escape - avoidant coping style were predictive of depressive symptoms. For state anxiety, similar patterns were observed. Quality of life and social support were significantly associated with lower anxiety. Carriers maintained higher knowledge compared to those testing negative, and were more engaged in screening. In summary, most individuals adapt to genetic test results over the long term and continue to engage in screening. A subgroup, including some non-carriers, may require added psychosocial support. PMID:25297893

  14. Long-term Psychosocial and Behavioral Adjustment in Individuals Receiving Genetic Test Results in Lynch Syndrome

    PubMed Central

    Esplen, MJ; Wong, J; Aronson, M; Butler, K; Rothenmund, H; Semotiuk, K; Madlensky, L; Way, C; Dicks, E; Green, J; Gallinger, S

    2014-01-01

    A cross-sectional study of 155 participants who underwent genetic testing for Lynch Syndrome (LS) examined long-term psychosocial and behavioral outcomes. Participants completed standardized measures of perceived risk, psychosocial functioning, knowledge, and a questionnaire of screening activities. Participants were on average 47.3 years and had undergone testing a mean of 5.5 years prior. Eighty four (54%) tested positive for a LS mutation and 71 (46%) negative. For unaffected carriers, perceived lifetime risk of colorectal cancer was 68%, and surprisingly, 40% among those testing negative. Most individuals demonstrated normative levels of psychosocial functioning. However, 25% of those testing negative had moderate depressive symptoms, as measured by the Center for Epidemiologic Studies for Depression Scale, and 31% elevated state anxiety on the State-Trait Anxiety Inventory. Being female and a stronger escape – avoidant coping style were predictive of depressive symptoms. For state anxiety, similar patterns were observed. Quality of life and social support were significantly associated with lower anxiety. Carriers maintained higher knowledge compared to those testing negative, and were more engaged in screening. In summary, most individuals adapt to genetic test results over the long term and continue to engage in screening. A subgroup, including some non-carriers, may require added psychosocial support. PMID:25297893

  15. Long term pre-qualification testing program on a 230kV XLPE cable system

    SciTech Connect

    Champion, T.C.; Agostinelli, F.M.; Rosevear, R.D.

    1994-12-31

    this paper describes the installation, testing, and results of a long term, full scale laboratory evaluation of a 230kV XLPE insulated cable system. System components included two innovative, pre-molded splices a 128 meter (420 foot) cable run, and two silicone oil filled, porcelain cable terminations. Load cycle aging was performed on the cable system over a four year period. After successfully completing the outdoor aging program, the system was exposed to a final impulses breakdown test. Results demonstrated the importance of considering thermomechanical bending in aluminum conductor, XLPE insulated designs. The influence on cable ampacity of solar heating at riser transitions was also demonstrated.

  16. Long term pre-qualification testing program on a 230kV XLPE cable system

    SciTech Connect

    Champion, T.C.; Agostinelli, F.M.; Rosevear, R.D.

    1995-01-01

    This paper describes the installation, testing, and results of a long term, full scale laboratory evaluation of a 230kV XLPE insulated cable system. System components included two innovative, pre-molded splices, a 128 meter (420 foot) cable run, and two silicone oil filled, porcelain cable terminations. Load cycle aging was performed on the cable system over a four year period. After successfully completing the outdoor aging program, the system was exposed to a final impulse breakdown test. Results demonstrated the importance or considering thermomechanical bending in aluminum conductor, XLPE insulated designs. The influence on cable ampacity of solar beating at riser transitions was also demonstrated.

  17. Multiple pollutant removal using the condensing heat exchanger. Task 3, Long term testing at the ECTC

    SciTech Connect

    Schulze, K.H.

    1996-01-01

    The objective of this task is to demonstrate long term operation of a condensing heat exchanger for coal-fired conditions. A small condensing heat exchanger will be installed at the Environmental Control Technology Center in Barker, New York. It will be installed downstream of the flue gas particulate removal system. The test will determine the amount of wear, if any, on the Teflon{trademark} covered internals of the heat exchanger. Visual inspection and measurements will be obtained for the Teflon{trademark} covered tubes during the test. The material wear study will conducted over a one year calendar period, and the CHX equipment will be operated to the fullest extent allowable.

  18. Long-term testing of advanced ceramics: Concerns, insights, and recommendations

    SciTech Connect

    Jenkins, M.G.

    1996-10-01

    Advanced ceramics have reached a level of material development to warrant serious consideration for use in advanced heat engine designs. Typically, design requirements based on service conditions may include 25,000 h lifetimes under stresses and temperatures of up to 250 MPa and 1,370 C, respectively, with probabilities of failure of < 0.1%. To assure that materials meet these stringent requirements requires long-term testing under the service conditions. Tensile tests at 1,370 C in ambient air have been conducted on silicon nitride alloys to 5,000 h with reports of 10,000 h tests for silicon carbide. To provide useful data, such long-term tests must incorporate such meticulous attention to detail as: strict temperature control ({+-} 5 C); accurate temperature measurement (1% of the nominal temperature); close control of grip cooling ({+-} 0.1 C) and ambient environment ({+-} 0.25 C); stable, high-resolution extensometry ({+-} 0.5 {micro}m); reliable heating (MTBF > 10,000 h) and load control (gravity-controlled, dead load), and responsive data acquisition systems (12-bit, digital collection). Data thus obtained can be used as input into design codes such as NASA CARES/LIFE to predict and confirm reliability/durability.

  19. Long-Term Operation Tests of Organic Solid-State Solar Cells

    NASA Astrophysics Data System (ADS)

    Shiokawa, Hiroki; Yokoyama, Masaaki; Hiramoto, Masahiro

    The long-term operation tests of two types of solid-state organic photovoltaic (OPV) cells, p-n heterojunction type cells and p-i-n junction type cells, were performed. In both cells, a drastic decrease in photocurrent within 1 h was observed in air. This rapid decrease was revealed to be caused by oxygen molecules which act as a electron trap in the electron transporting organic layer. Initial decrease of photocurrent was effectively suppressed under high vacuum (10-7 Torr). In the case of a p-n type cell, the decrease in short-circuit photocurrent was only 15% even under prolonged light irradiation of 260 h.

  20. Analysis of long-term fluctuations in stream flow time series: An application to Litani River, Lebanon

    NASA Astrophysics Data System (ADS)

    Shaban, Amin; Telesca, Luciano; Darwich, Talal; Amacha, Nabil

    2014-02-01

    Litani River is the largest river in Lebanon and has been affected by several physical and anthropogenic factors that influenced its flow dynamics. By means of the Singular Spectrum Analysis (SSA), the time dynamics of the stream flow of seven sites along the course of Litani River was investigated, extracting for each site the long-term trend. A clear decreasing trend characterizes all the long-term trends of the stream flow. Furthermore, several peaks were identified, consistent with the rainfall rate and snow cover variability.

  1. Long-term prediction test procedure for most ICs, based on linear response theory

    NASA Technical Reports Server (NTRS)

    Litovchenko, V.; Ivakhnenko, I.

    1991-01-01

    Experimentally, thermal annealing is known to be a factor which enables a number of different integrated circuits (IC's) to recover their operating characteristics after suffering radiation damage in the space radiation environment; thus, decreasing and limiting long term cumulative total-dose effects. This annealing is also known to be accelerated at elevated temperatures both during and after irradiation. Linear response theory (LRT) was applied, and a linear response function (LRF) to predict the radiation/annealing response of sensitive parameters of IC's for long term (several months or years) exposure to the space radiation environment were constructed. Compressing the annealing process from several years in orbit to just a few hours or days in the laboratory is achieved by subjecting the IC to elevated temperatures or by increasing the typical spaceflight dose rate by several orders of magnitude for simultaneous radiation/annealing only. The accomplishments are as follows: (1) the test procedure to make predictions of the radiation response was developed; (2) the calculation of the shift in the threshold potential due to the charge distribution in the oxide was written; (3) electron tunneling processes from the bulk Si to the oxide region in an MOS IC were estimated; (4) in order to connect the experimental annealing data to the theoretical model, constants of the model of the basic annealing process were established; (5) experimental data obtained at elevated temperatures were analyzed; (6) time compression and reliability of predictions for the long term region were shown; (7) a method to compress test time and to make predictions of response for the nonlinear region was proposed; and (8) nonlinearity of the LRF with respect to log(t) was calculated theoretically from a model.

  2. Design and Field Test of a WSN Platform Prototype for Long-Term Environmental Monitoring

    PubMed Central

    Lazarescu, Mihai T.

    2015-01-01

    Long-term wildfire monitoring using distributed in situ temperature sensors is an accurate, yet demanding environmental monitoring application, which requires long-life, low-maintenance, low-cost sensors and a simple, fast, error-proof deployment procedure. We present in this paper the most important design considerations and optimizations of all elements of a low-cost WSN platform prototype for long-term, low-maintenance pervasive wildfire monitoring, its preparation for a nearly three-month field test, the analysis of the causes of failure during the test and the lessons learned for platform improvement. The main components of the total cost of the platform (nodes, deployment and maintenance) are carefully analyzed and optimized for this application. The gateways are designed to operate with resources that are generally used for sensor nodes, while the requirements and cost of the sensor nodes are significantly lower. We define and test in simulation and in the field experiment a simple, but effective communication protocol for this application. It helps to lower the cost of the nodes and field deployment procedure, while extending the theoretical lifetime of the sensor nodes to over 16 years on a single 1 Ah lithium battery. PMID:25912349

  3. Long term materials test program. Quarterly report, April-June 1983

    SciTech Connect

    Not Available

    1984-01-01

    Corrosion and erosion/corrosion testing of gas turbine materials in the effluent from a pressurized fluidized bed coal combustor continues under the Long Term Materials Test program. Two 1000-hour erosion/corrosion screening tests of twelve candidate gas turbine vane and blade base alloys and a variety of protective coating systems have been completed. Test conditions included 1350/sup 0/F, 800 to 900 ft/s and particulate loadings of 30 to 90 ppM. Erosion/corrosion degradation rates of 1 to 4 mils/1000 hours were observed with corrosion predominant in areas of particle impaction. FeCrAlY, CoCrAlY and rhodium aluminide coatings show significantly better resistance to degradation than unprotected base alloys, aluminide or platinum-aluminide diffusion coatings.

  4. Flexor carpi ulnaris transfer for radial nerve palsy: functional testing of long-term results.

    PubMed

    Raskin, K B; Wilgis, E F

    1995-09-01

    Controversy persists over the use of the flexor carpi ulnaris for transfer to the extensor digitorum communis in the treatment of radial nerve palsy. Six patients with complete, irreparable radial nerve palsies were treated in part with the flexor carpi ulnaris to extensor digitorum communis tendon transfer (standard transfers: pronator teres to extensor carpi radialis brevis, flexor carpi ulnaris to extensor digitorum communis, and palmaris longus to the rerouted extensor pollicis longus) and were functionally tested for long-term results. The average follow-up time was 8 years (range, 3-15). A control group was comprised of 10 volunteers of similar demographics. This study evaluates the long-term functional recovery in three categories: range of motion, dynamic power of wrist motion, and functional ability as determined by work simulation techniques. The activities simulated were swinging a hammer, sawing wood, tightening screws, and using pliers. A functional range of motion was maintained in all patients, and the power of wrist motion was sufficient to perform all activities of daily living. The work simulation testing revealed no significant difference between the tendon transfer patients and control group with respect to hand dominance and normal variance. All patients were able to perform the simulated work with the same variance in power as the control group. Despite the obvious anatomic loss, wrist function is not significantly impaired after flexor carpi ulnaris tendon transfer for radial nerve palsy. PMID:8522738

  5. Design and fabrication of a unique electromechanical machine for long-term fatigue testing

    SciTech Connect

    Boling, K.W.

    1984-12-01

    An electromechanical machine has been designed and fabricated for performing long-term fatigue tests under conditions that simulate those in modern plants. The machine is now commercially available. Its advantages over current electrohydraulic machines are lower initial cost, minimum maintenance requirements, and greater reliability especially when performing long tests. The machine operates in closed-loop fashion by utilizing continuous feedback signals from the specimen extensometer or load cell, it is programmable for testing in strain or load control. The maximum ram rate is 0.056 mm/s (0.134 in./min), maximum ram travel is 102 mm (4 in.) and load capacity is +-44 (+-10 kips). Induction heating controls speciment temperatures to 1000/sup 0/C.

  6. Using global statistical tests in long-term Parkinson's disease clinical trials.

    PubMed

    Huang, Peng; Goetz, Christopher G; Woolson, Robert F; Tilley, Barbara; Kerr, Douglas; Palesch, Yuko; Elm, Jordan; Ravina, Bernard; Bergmann, Kenneth J; Kieburtz, Karl

    2009-09-15

    Parkinson's disease (PD) impairments are multidimensional, making it difficult to choose a single primary outcome when evaluating treatments to stop or lessen the long-term decline in PD. We review commonly used multivariate statistical methods for assessing a treatment's global impact, and we highlight the novel Global Statistical Test (GST) methodology. We compare the GST to other multivariate approaches using data from two PD trials. In one trial where the treatment showed consistent improvement on all primary and secondary outcomes, the GST was more powerful than other methods in demonstrating significant improvement. In the trial where treatment induced both improvement and deterioration in key outcomes, the GST failed to demonstrate statistical evidence even though other techniques showed significant improvement. Based on the statistical properties of the GST and its relevance to overall treatment benefit, the GST appears particularly well suited for a disease like PD where disability and impairment reflect dysfunction of diverse brain systems and where both disease and treatment side effects impact quality of life. In future long term trials, use of GST for primary statistical analysis would allow the assessment of clinically relevant outcomes rather than the artificial selection of a single primary outcome. PMID:19514076

  7. Using Global Statistical Tests in Long-Term Parkinson’s Disease Clinical Trials

    PubMed Central

    Huang, Peng; Goetz, Christopher G.; Woolson, Robert F.; Tilley, Barbara; Kerr, Douglas; Palesch, Yuko; Elm, Jordan; Ravina, Bernard; Bergmann, Kenneth J.; Kieburtz, Karl

    2010-01-01

    Parkinson’s disease (PD) impairments are multidimensional, making it difficult to choose a single primary outcome when evaluating treatments to stop or lessen the long-term decline in PD. We review commonly used multivariate statistical methods for assessing a treatment’s global impact, and we highlight the novel Global Statistical Test (GST) methodology. We compare the GST to other multivariate approaches using data from two PD trials. In one trial where the treatment showed consistent improvement on all primary and secondary outcomes, the GST was more powerful than other methods in demonstrating significant improvement. In the trial where treatment induced both improvement and deterioration in key outcomes, the GST failed to demonstrate statistical evidence even though other techniques showed significant improvement. Based on the statistical properties of the GST and its relevance to overall treatment benefit, the GST appears particularly well suited for a disease like PD where disability and impairment reflect dysfunction of diverse brain systems and where both disease and treatment side effects impact quality of life. In future long term trials, use of GST for primary statistical analysis would allow the assessment of clinically relevant outcomes rather than the artificial selection of a single primary outcome. PMID:19514076

  8. Lessons Learned During the Refurbishment and Testing of an Observatory After Long-Term Storage

    NASA Technical Reports Server (NTRS)

    Hawk, John; Peabody, Sharon; Stavely, Richard

    2015-01-01

    Thermal Fluids Analysis Workshop (TFAWS) 2015, Silver Spring, MD NCTS 21070-15. This paper addresses the lessons learned during the refurbishment and testing of the thermal control system for a spacecraft which was placed into long-term storage. The DSCOVR (Deep Space Climate Observatory) Observatory (formerly known as Triana) was originally scheduled to launch on the Space Shuttle in 2002. With the Triana spacecraft nearly complete, the mission was canceled and the satellite was abruptly put into storage in 2001. In 2008 the observatory was removed from storage to begin refurbishment and testing. Problems arose associated with hardware that was not currently manufactured, coatings degradation, and a significant lack of documentation. Also addressed is the conversion of the thermal and geometric math models for use with updated thermal analysis software tools.

  9. Accelerated Testing for Long-Term Durability of Various FRP Laminates for Marine Use

    NASA Astrophysics Data System (ADS)

    Miyano, Yasushi; Nakada, Masayuki

    The prediction of long-term fatigue life of various FRP laminates combined with resins, fibers and fabrics for marine use under temperature and water environments were performed by our developed accelerated testing methodology based on the time-temperature superposition principle (TTSP). The base material of five kinds of FRP laminates employed in this study was plain fabric CFRP laminates T300 carbon fibers/vinylester (T300/VE). The first selection of FRP laminate to T300/VE was the combinations of different fabrics, that is flat yarn plain fabric T700 carbon fibers/vinylester (T700/VE-F) and multi-axial knitted T700 carbon fibers/vinylester (T700/VE-K) for marine use and the second selection of FRP laminates to T300/VE was the combinations with different fibers and matrix resin, that is plain fabric T300 carbon fibers/epoxy (T300/EP) and plain fabric E-glass fibers/vinylester (E-glass/VE). These five kinds of FRP laminates were prepared under three water absorption conditions of Dry, Wet and Wet C Dry after molding. The three-point bending constant strain rate (CSR) tests for these FRP laminates at three conditions of water absorption were carried out at various temperatures and strain rates. Furthermore, the three-point bending fatigue tests for these specimens were carried out at various temperatures and frequencies. The flexural CSR and fatigue strengths of these five kinds of FRP laminates strongly depend on water absorption as well as time and temperature. The mater curves of fatigue strength as well as CSR strength for these FRP laminates at three water absorption conditions are constructed by using the test data based on TTSP. It is possible to predict the long term fatigue life for these FRP laminates under an arbitrary temperature and water absorption conditions by using the master curves.

  10. Interlaboratory evaluation of Hyalella azteca and Chironomus tentans short-term and long-term sediment toxicity tests

    USGS Publications Warehouse

    Norberg-King, T. J.; Sibley, P.K.; Burton, G.A.; Ingersoll, C.G.; Kemble, N.E.; Ireland, S.; Mount, D.R.; Rowland, C.D.

    2006-01-01

    Methods for assessing the long-term toxicity of sediments to Hyalella azteca and Chironomus tentans can significantly enhance the capacity to assess sublethal effects of contaminated sediments through multiple endpoints. Sublethal tests allow us to begin to understand the relationship between short-term and long-term effects for toxic sediments. We present an interlaboratory evaluation with long-term and 10-d tests using control and contaminated sediments in which we assess whether proposed and existing performance criteria (test acceptability criteria [TAC]) could be achieved. Laboratories became familiar with newly developed, long-term protocols by testing two control sediments in phase 1. In phase 2, the 10-d and long-term tests were examined with several sediments. Laboratories met the TACs, but results varied depending on the test organism, test duration, and endpoints. For the long-term tests in phase 1, 66 to 100% of the laboratories consistently met the TACs for survival, growth, or reproduction using H. azteca, and 70 to 100% of the laboratories met the TACs for survival and growth, emergence, reproduction, and hatchability using C. tentans. In phase 2, fewer laboratories participated in long-term tests: 71 to 88% of the laboratories met the TAC for H. azteca, whereas 50 to 67% met the TAC for C. tentans. In the 10-d tests with H. azteca and C. tentans, 82 and 88% of the laboratories met the TAC for survival, respectively, and 80% met the TAC for C. tentans growth. For the 10-d and long-term tests, laboratories predicted similar toxicity. Overall, the interlaboratory evaluation showed good precision of the methods, appropriate endpoints were incorporated into the test protocols, and tests effectively predicted the toxicity of sediments. ?? 2006 SETAC.

  11. Technical description of the NRC long-term whole-rod and crud performance test

    SciTech Connect

    Einziger, R.E.; Fish, R.L.; Knecht, R.L.

    1982-09-01

    Westinghouse Hanford Company (WHC) and EG and G-Idaho are jointly conducting a long-term, low-temperature, spent-fuel, whole rod and crud behavior test to provide the Nuclear Regulatory Commission (NRC) with information to assist in the licensing of light water reactor (LWR) spent-fuel, dry storage facilities. Readily available fuel rods from an H.B. Robinson Unit 2 (PWR) fuel assembly and a Peach Bottom-II (BWR) fuel assembly were selected for use in the 50-month test. Both intact and defected rods will be tested in inert and oxidizing atmospheres. A 230/sup 0/C test temperature was selected for the first 10-month run. Both nondestructive and destructive examinations are planned to characterize the fuel rod behavior during the 5-y test. Four interim examinations and a final examination will be conducted. Crud spallation behavior will be investigated by sampling the crud particulate from the test capsules at each of the four interim examinations and at the end of the test. The background to whole rod testing, description of rod breach mechanisms, and a detailed description of the test are presented in this document.

  12. Long term impacts of flow abstraction upon basin scale sedimentation processes in an Alpine valley system

    NASA Astrophysics Data System (ADS)

    Lane, Stuart; Regamey, Benoit

    2014-05-01

    Flow abstraction and diversion to large water storage systems is a common element of Alpine hydro-electric power schemes. However, such systems are commonly associated with exceptionally high sediment production rates, necessitating very particular approaches to sediment management. Commonly, whilst water is abstracted, sediment (both coarse and fine fractions) is left behind. In order to avoid infrastructure failure, the latter is commonly designed to allow sediment to pass in short duration high magnitude sedimentary floods. The importance of such schemes aside, there has been relatively little investigation of the geomorphic impacts of such sediment management systems. In this paper, we present results from two spatio-temporal scales of analysis in order to establish these impacts. The first applies image processing to archival aerial photography to document the long-term impacts of flow abstraction and sedimentary floods in the Val d'Héréns, Switzerland. Results show that flow abstraction significantly reduces the time when the river was competent to transport sediment, and hence the total sediment transport capacity. The result has been a temporary disconnection of sediment flux through the system, and reflected in significantly reduced rates of sediment delivery to Lac Léman downstream. However, the image analysis also shows that whilst sedimentation was initially restricted to close to the abstraction sites, this sediment has been progressively reworked through a succession of sedimentary floods, causing deposition sites to move progressively further downstream. These deposition sites are themselves constrained by geomorphic forcing, centred on reaches of lower river bed slope and with sufficient lateral accommodation space. The implication of these observations is that the sediment flux will eventually reconnect with the main valley stems further downstream. The second scale sought to quantify this response in more detail by laser scanning on a 400 m

  13. Long-term macroinvertebrate response to flow abstraction at Alpine water intakes

    NASA Astrophysics Data System (ADS)

    Gabbud, Chrystelle; Savioz, Amélie; Lane, Stuart

    2016-04-01

    The natural flow hydrological characteristics of Alpine streams, dominated by snowmelt and glacier melt, have been established for many years. More recently, the ecosystems that they sustain have been described and explained, following the hydrological, biochemical, morphodynamic, and biotic elements specific to Alpine streams. However, natural Alpine flow regimes may be strongly modified by hydroelectric power production, which impacts upon both river discharge and sediment transfer, and hence on downstream flora and fauna. These kinds of impacts are well studied where river are regulated by dams, with sediments retained behind walls, but they are much less focus on water intakes, whose storage capacity is very smaller and thus have to flush flow and sediment regularly. Here we focus on the impacts of flow abstraction on macroinvertebrates, the most widely ecological group used in freshwater biomonitoring as they act typically as indicators of environmental health. Some key generalizations can be made. For instance, in European glacially fed river systems, Plecoptera, Chironomidae, Ephemeroptera, Simuliidae, and Diptera are the main taxa found in spring as they are better adapted to cold conditions. Petts and Bickerton (1994) published macroinvertebrate samples from the upper part of the glacial stream system the Borgne d'Arolla (Valais, Switzerland), highlighting that: (1) taxa variability and productivity decline in the river because of flow abstraction, (2) 60 % of the communities were provided by tributaries, (3) there is migration upstream of the species in response to the passage from a dominant ice-melt to a snow-melt regime, (4) the colonisation is difficult because of a significant modification of the habitat in the river by sediment transport, until it becomes warmer, clearer and more stable further downstream. In order to establish the long-term impacts of flow abstraction upon instream ecology where sediment delivery is maintained but transport

  14. Long-Term Correlations and Multifractality of Traffic Flow Measured by GIS for Congested and Free-Flow Roads

    NASA Astrophysics Data System (ADS)

    di, Baofeng; Shi, Kai; Zhang, Kaishan; Svirchev, Laurence; Hu, Xiaoxi

    2016-02-01

    In this paper, a GIS-based method was developed to extract the real-time traffic information (RTTI) from the Google Maps system for city roads. The method can be used to quantify both congested and free-flow traffic conditions. The roadway length was defined as congested length (CL) and free-flow length (FFL). Chengdu, the capital of Sichuan Province in the southwest of China, was chosen as a case study site. The RTTI data were extracted from the Google real-time maps in May 12-17, 2013 and were used to derive the CL and FFL for the study areas. The Multifractal Detrended Fluctuation Analysis (MFDFA) was used to characterize the long-term correlations of CL and FFL time series and their corresponding multifractal properties. Analysis showed that CL and FFL had demonstrated time nonlinearity and long-term correlations and both characteristics differed significantly. A shuffling procedure and a phase randomization procedure were further integrated with multifractal detrending moving average (MFDMA) to identify the major sources of multifractality of these two time series. The results showed that a multifractal process analysis could be used to characterize complex traffic data. Traffic data collected and methods developed in this paper will help better understand the complex traffic systems.

  15. Long-term testing of in-situ cerium oxide coated anodes for aluminum electrowinning

    SciTech Connect

    King, H.L.

    1989-10-01

    The ELTECH Anode Phase 2 Project (Contract Number AC07-86ID12655), as supported by the Department of Energy (DOE) from December 1988 through April 1989, focused on long-term testing of in-situ anodically deposited cerium oxide (CEROX) coatings on nickel ferrite/Cu cermets. The specific objective of this research was to determine the effectiveness of the CEROX coating in reducing the transfer of cermet components to the produced aluminum. A dosing regimen was first established for the minimum addition of cerium to the cell necessary to produce targeted CEROX coatings on the cermet anode and the periodic additions necessary to maintain coating thicknesses. The effects of the addition of CeF{sub 3} on CEROX coating formation was evaluated for targeted coating thicknesses at three different current densities. Analytical procedures were identified for determining alumina concentrations and the cryolite bath ratio for quasi-commercial baths.

  16. Long-term leaching test of incinerator bottom ash: Evaluation of Cu partition

    SciTech Connect

    Lin, Cheng-Fang Wu, Chung-Hsin; Liu, Yen-Chiun

    2007-07-01

    Two types of leaching tests were performed on the bottom ash from municipal solid waste incinerators. A short-term batch test specified by the America Nuclear Society (ANS) and long-term column tests with acetic acid (pH 5.2) as leaching solution were used to evaluate copper leachability. The Cu leaching after the 5-d ANS test is about 1% of the original Cu content of 5300 mg/kg. Upon addition of a stabilizing agent, the Cu leaching quantity is reduced; the extent of reduction depends on the type of chemical used (phosphate, carbonate and sulfide). The 1.6% Na{sub 2}S addition showed negligible Cu leaching, and Na{sub 2}S was, therefore, used in subsequent column tests. The 30-d column test indicates a steady increase of Cu leaching amount with time and reaches about 1.5% of the original Cu content after 30 d. A 180-d column test further increased the Cu leaching to about 5.1% of the original Cu content, whereas no appreciable Cu leaching was found with the addition of 1.6% Na{sub 2}S. A sequential extraction was conducted on the raw ash, ash with the addition of Na{sub 2}S and the residue ash after 30 d of operation to characterize Cu affinity for different solid fractions. The data were used to evaluate the fate of Cu through these interactions.

  17. Long-term product consistency test of simulated 90-19/Nd HLW glass

    NASA Astrophysics Data System (ADS)

    Gan, X. Y.; Zhang, Z. T.; Yuan, W. Y.; Wang, L.; Bai, Y.; Ma, H.

    2011-01-01

    Chemical durability of 90-19/Nd glass, a simulated high-level waste (HLW) glass in contact with the groundwater was investigated with a long-term product consistency test (PCT). Generally, it is difficult to observe the long term property of HLW glass due to the slow corrosion rate in a mild condition. In order to overcome this problem, increased contacting surface ( S/ V = 6000 m -1) and elevated temperature (150 °C) were employed to accelerate the glass corrosion evolution. The micro-morphological characteristics of the glass surface and the secondary minerals formed after the glass alteration were analyzed by SEM-EDS and XRD, and concentrations of elements in the leaching solution were determined by ICP-AES. In our experiments, two types of minerals, which have great impact on glass dissolution, were found to form on 90-19/Nd HLW glass surface when it was subjected to a long-term leaching in the groundwater. One is Mg-Fe-rich phyllosilicates with honeycomb structure; the other is aluminosilicates (zeolites). Mg and Fe in the leaching solution participated in the formation of phyllosilicates. The main components of phyllosilicates in alteration products of 90-19/Nd HLW glass are nontronite (Na 0.3Fe 2Si 4O 10(OH) 2·4H 2O) and montmorillonite (Ca 0.2(Al,Mg) 2Si 4O 10(OH) 2·4H 2O), and those of aluminosilicates are mordenite ((Na 2,K 2,Ca)Al 2Si 10O 24·7H 2O)) and clinoptilolite ((Na,K,Ca) 5Al 6Si 30O 72·18H 2O). Minerals like Ca(Mg)SO 4 and CaCO 3 with low solubility limits are prone to form precipitant on the glass surface. Appearance of the phyllosilicates and aluminosilicates result in the dissolution rate of 90-19/Nd HLW glass resumed, which is increased by several times over the stable rate. As further dissolution of the glass, both B and Na in the glass were found to leach out in borax form.

  18. Long-term Monitoring Plan for the Shoal Underground Nuclear Test

    SciTech Connect

    Ahmed Hassan

    2005-02-01

    The flow and transport model of Shoal is used to design a three-well monitoring network to be part of the long-term monitoring network for the site and achieve two objectives: (1) detect the presence of radionuclides in case they migrate to the monitoring well locations, and (2) provide field data to compare with model predictions as part of the model validation process. Using three different quantitative approaches and the numerical groundwater flow and transport model developed for Shoal, three new monitoring well locations were identified from 176 different networks. In addition to the quantitative analyses using the numerical model, the development of the monitoring network for Shoal will also be subject to qualitative hydrogeologic interpretation during implementation. information will only be available during the fieldwork, it will be incorporated in the monitoring well design at the time of well installation. Finally, it should be noted that the CADD-CAP for Shoal, including the compliance boundary, is not yet approved. Should the compliance boundary change from the 1,000-year MCL contaminant boundary, well locations may also need to change. However, the analysis reported here provides a number of alternatives with reasonable detection efficiency.

  19. Long-term soil organic carbon changes in cereal and ley rotations: model testing

    NASA Astrophysics Data System (ADS)

    Kynding Borgen, Signe; Dörsch, Peter; Krogstad, Tore; Azzaroli Bleken, Marina

    2015-04-01

    Reliable modeling of soil organic carbon (SOC) dynamics in agroecosystems is crucial to define mitigation strategies related to crop management on the farm scale as well as the regional scale. International climate agreements and national political decisions rely to a large extent on the National Greenhouse gas Inventory Reports that are submitted annually to the UNFCCC. However, lower tier methods are used to estimate SOC changes on cropland in most country reports. The application of mechanistic models in national greenhouse gas inventory estimation requires proper model testing against measurements in order to verify the estimated emissions. Few long-term field experiments measuring SOC stock changes have been conducted in Norway. We evaluate the performance of the Introductory Carbon Balance Model (ICBM) in simulating SOC changes over 60 years in a field experiment conducted in Ås from 1953-2013. The site is located in south-eastern Norway, on the boarder of the boreal and temperate climate zone, where the majority of the country's grain production occurs. The field trial consisted of four rotations: I) continuous cereal, II) cereal + row crops, III) 2 years of ley + 4 years of cereal, IV) 4 years of ley + 2 years of cereal, and four treatments per rotation: a) low NPK, b) high NPK, c) low NPK + FYM, and d) straw (on rotations I and II) or high NPK + FYM (on rotations III and IV). The annual external modifying factor of the decomposition rate was calculated based on daily minimum and maximum temperature, precipitation, relative humidity, wind speed, and net radiation, and adjusted for soil type and crop management according to default ICBM calibration. We present results of simulated C changes for the long term plots and explore options to improve parameter calibration. Finally, we provide suggestions for how problems regarding model verification can be handled with when applying the model on a national scale for inventory reporting.

  20. Quantifying long-term microelectrode array functionality using chronic in vivo impedance testing.

    PubMed

    Prasad, Abhishek; Sanchez, Justin C

    2012-04-01

    Long-term acquisition of high-quality neural recordings is a cornerstone of neuroprosthetic system design. Mitigating the experimental variability of chronically implanted arrays has been a formidable task because the sensor recording sites can be influenced by biotic and abiotic responses. Several studies have implicated changes in electrical interface impedance as a preliminary marker to infer electrode viability. Microelectrode impedance plays an important role in the monitoring of low amplitude and high-resolution extracellular neural signals. In this work, we seek to quantify long-term microelectrode array functionality and derive an impedance-based predictor for electrode functionality that correlates the recording site electrical properties with the functional neuronal recordings in vivo. High temporal resolution metrics of this type would allow one to assess, predict, and improve electrode performance in the future. In a large cohort of animals, we performed daily impedance measurements and neural signal recordings over long periods (up to 21 weeks) of time in rats using tungsten microwire arrays implanted into the somatosensory cortex. This study revealed that there was a time-varying trend in the modulation of impedance that was related to electrode performance. Single units were best detected from electrodes at time points when the electrode entered into the 40-150 KΩ impedance range. This impedance trend was modeled across the full cohort of animals to predict future electrode performance. The model was tested on data from all animals and was able to provide predictions of electrode performance chronically. Insight from this study can be combined with knowledge of electrode materials and histological analysis to provide a more comprehensive predictive model of electrode failure in the future. PMID:22442134

  1. Quantifying long-term microelectrode array functionality using chronic in vivo impedance testing

    NASA Astrophysics Data System (ADS)

    Prasad, Abhishek; Sanchez, Justin C.

    2012-04-01

    Long-term acquisition of high-quality neural recordings is a cornerstone of neuroprosthetic system design. Mitigating the experimental variability of chronically implanted arrays has been a formidable task because the sensor recording sites can be influenced by biotic and abiotic responses. Several studies have implicated changes in electrical interface impedance as a preliminary marker to infer electrode viability. Microelectrode impedance plays an important role in the monitoring of low amplitude and high-resolution extracellular neural signals. In this work, we seek to quantify long-term microelectrode array functionality and derive an impedance-based predictor for electrode functionality that correlates the recording site electrical properties with the functional neuronal recordings in vivo. High temporal resolution metrics of this type would allow one to assess, predict, and improve electrode performance in the future. In a large cohort of animals, we performed daily impedance measurements and neural signal recordings over long periods (up to 21 weeks) of time in rats using tungsten microwire arrays implanted into the somatosensory cortex. This study revealed that there was a time-varying trend in the modulation of impedance that was related to electrode performance. Single units were best detected from electrodes at time points when the electrode entered into the 40-150 KΩ impedance range. This impedance trend was modeled across the full cohort of animals to predict future electrode performance. The model was tested on data from all animals and was able to provide predictions of electrode performance chronically. Insight from this study can be combined with knowledge of electrode materials and histological analysis to provide a more comprehensive predictive model of electrode failure in the future.

  2. Long-term test-retest reliability of delayed reward discounting in adolescents.

    PubMed

    Anokhin, Andrey P; Golosheykin, Simon; Mulligan, Richard C

    2015-02-01

    Delay discounting (DD), a decline in subjective value of a reward with increasing temporal delay in receipt of that reward, is an established behavioral indicator of impulsivity. Preference for smaller-immediate over larger-delayed rewards has been implicated in the basic neurobehavioral mechanisms of risk for addictive disorders and related externalizing psychopathology. Establishing long-term stability of DD in adolescence is a necessary step towards its validation as an intermediate phenotype, or marker of risk, in neurobiological and genetic studies. Previous studies have demonstrated moderate to high test-retest reliability of DD, however, these studies utilized adult samples and examined relatively short retest intervals. Due to continuing development of brain and behavior, stability of temporal discounting behavior in adolescence may differ from that in adulthood. Here, two cohorts of adolescents aged 16 (n=126) and 18 (n=111) were administered a computerized test of DD and re-tested two years later. DD rate showed a modest but significant decrease with age, suggesting a reduction in overall impulsivity from middle to late adolescence. Significant test-retest correlations were observed in both cohorts (.67 and .76, respectively, p<.001) indicating longitudinal stability of individual differences in decision-making behavior during middle and late adolescence. This article is part of a Special Issue entitled: insert SI title. PMID:25447508

  3. Some Trends in Radioactive Waste Form Behavior Revealed in Long-Term Field Tests

    SciTech Connect

    Ojovan, M. I.; Ojovan, N. V.; Startceva, I. V.; Barinov, A. S.

    2002-02-25

    Results from long-term field tests with borosilicate glass, cement and bitumen waste forms containing actual intermediate-level radioactive waste are summarized and discussed in the paper. Leaching behavior of the waste forms was evaluated by monitoring the contamination of contacting water. Measured leach rates of the three waste-form materials were in a narrow range in shallow subsurface repositories, but varied in a wide range at an open testing site owing to weathering of bitumen and cement materials. The repositories were opened after 12-year testing for visual examination, sampling and analysis. All retrieved waste forms were in good physical condition. The study has not revealed any negative changes in the waste glass. Some ageing processes were detected in cement and bitumen waste forms, which can positively (bitumen) or negatively (cement) affect physical and containment properties of these waste materials. It has been established that a significant proportion of the radioactive inventory in the bitumen waste form became associated with the bitumen phase. Phase separation of this radioactive bitumen has shown, than the asphaltene fraction is responsible for the major part of the radioactivity retained by the bitumen.

  4. Long-term storage life of light source modules by temperature cycling accelerated life test

    NASA Astrophysics Data System (ADS)

    Ningning, Sun; Manqing, Tan; Ping, Li; Jian, Jiao; Xiaofeng, Guo; Wentao, Guo

    2014-05-01

    Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG.

  5. Long Term Materials Test Program. Quarterly report, July-September 1983

    SciTech Connect

    Not Available

    1984-04-01

    Corrosion and erosion/corrosion testing of gas turbine vane and blade base alloys and a variety of protective coating systems under the Long Term Materials Test program has surpassed 3400 hours. The PFBC facility at Malta, New York continues to show an exceptionally high degree of reliability and consistency in performance. Operating conditions include a 1650/sup 0/F bed temperature at 10 atmospheres pressures utilizing Pittsburgh No. 8 coal and a low alkali dolomite sulfur sorbent. After 2687 hours, unprotected nickel and cobalt base vane and blade alloys generally experienced corrosion rates of 1 to 2 mils/1000 hours at metal temperatures of 1100, 1300, and 1500/sup 0/F. Precious metal aluminide and MCrAlY coatings continue to show excellent corrosion resistance (<0.5 mils/1000 hrs) at 1500/sup 0/F, but are susceptible to varying degrees of pitting attack at 1100/sup 0/ and 1300/sup 0/F. Erosion/corrosion degradation rates at 800 to 900 fps., 1350/sup 0/F and less than 100 ppM dust loading ranged from 1 to 4 mils/1000 hours with corrosion predominately concentrated in areas of particle impaction indicating an erosion/corrosion synergism.

  6. Long term materials test program. Quarterly report, October-December 1983

    SciTech Connect

    Not Available

    1984-01-01

    The long-term exposure of gas turbine vane and blade base alloys and a variety of protective coating systems to the effluent from a pressurized fluidized bed coal combustor has reached 4398 hours. After 4053 hours, FeCrAlY overlay coatings and platinum/rhodium-aluminide pack diffusion coatings show excellent resistance to corrosion attack at 1500/sup 0/F. Cobalt-base coatings are somewhat more susceptible to hot corrosion, and the unprotected nickel and cobalt-base alloys are most susceptible to corrosion, although corrosion rates have decreased to less than 1 mil/1000 hours for all materials at 1500/sup 0/F; i.e., corrosion penetration data is evolving parabolically. The three-stage cyclone cleanup system became severely distorted after approximately 5600 hours total service life. Distortion of the cyclones contributed to an increased dust loading to the material test sections, 110 to 250 ppM versus normal loadings of 30 to 90 ppM, for a period of about 75 hours. This increase in dust loading caused severe erosion of the airfoils in the high-velocity test section. Metal recession ranged 4 to 18 mils of leading edge loss on the impulse airfoils, and 11 to 27 mils of leading edge loss on the reaction airfoils. A new three-stage cyclone system was installed and dust loadings now range from 15 to 45 ppM.

  7. Long-term materials test program. Quarterly report, January-March 1983

    SciTech Connect

    1984-03-01

    Exposure of gas turbine materials to a PFBC effluent under the Long-Term Materials Test Program has reached 1507 hours. Unprotected nickel and cobalt base blade and vane alloys show susceptibility to hot corrosion at 1500/sup 0/F (gas temperature), 1300/sup 0/F, and 1100/sup 0/F (air-cooled pins). Precious metal aluminide and M (Co,Fe) CrAlY overlay coatings continue to show good resistance to corrosion above 1450/sup 0/F, but are susceptible to varying degrees of pitting attack between 1050 and 1300/sup 0/F. Significant erosion/corrosion degradation of both base alloys and protective coatings/claddings has been observed on airfoil specimens exposed at 1350/sup 0/F, 800 to 900 fps and dust loadings less than 100 ppM for 1085 hours. Corrosion predominately occurred in areas of direct particle impaction; i.e., leading edge and pressure surface, indicating an erosion/corrosion synergism. At gas velocities of 1200 to 1400 fps, a platinum-aluminide coated IN-738 pin experienced a metal recession rate of 8 mils/1000-hours. The PFBC facility continues to show excellent operational reliability, accumulating over 1100 test hours this quarter. The only concern from an operations standpoint is the gradual thinning of the in-bed heat exchanger tubing at a rate of about 5 mils/100 hours off the diameter.

  8. Quality testing of autoclaved rodent drinking water during short-term and long-term storage.

    PubMed

    Peveler, Jessica L; Crisler, Robin; Hickman, Deb

    2015-06-01

    All animals need clean water to drink. At the authors' animal facility, drinking water for immunocompromised rodents is filtered by reverse osmosis, acidified during bottling and sterilized in an autoclave. Autoclaved water bottles can be stored in unopened autoclave bags for 7 d or in opened bags for 2 d; if not used during that time, they are emptied, cleaned, refilled and sterilized again. The authors wished to determine whether the storage period of 2-7 d was adequate and necessary to ensure the quality of drinking water. They tested water bottles for pH levels and for the presence of adenosine triphosphate as a measure of organic contamination during short-term and long-term storage. The pH of autoclaved drinking water generally remained stable during storage. Furthermore, no instances of organic contamination were detected in autoclaved water bottles stored for up to 22 d in unopened bags and only one instance was detected in bottles stored for up to 119 d in opened bags in a room with individually ventilated cages. On the basis of these findings, the acceptable storage period for autoclaved water bottles in opened bags at the authors' facility was extended to 21 d. PMID:25989554

  9. Long-term aging and loss-of-coolant accident (LOCA) testing of electrical cables

    SciTech Connect

    Nelson, C.F.; Gauthier, G.; Carlin, F.

    1996-10-01

    Experiments were performed to assess the aging degradation and loss-of-coolant accident (LOCA) behavior of electrical cables subjected to long-term aging exposures. Four different cable types were tested in both the U.S. and France: (1) U.S. 2 conductor with ethylene propylene rubber (EPR) insulation and a Hypalon jacket. (2) U.S. 3 conductor with cross-linked polyethylene (XLPE) insulation and a Hypalon jacket. (3) French 3 conductor with EPR insulation and a Hypalon jacket. (4) French coaxial with polyethylene (PE) insulation and a PE jacket. The data represent up to 5 years of simultaneous aging where the cables were exposed to identical aging radiation doses at either 40{degrees}C or 70{degrees}C; however, the dose rate used for the aging irradiation was varied over a wide range (2-100 Gy/hr). Aging was followed by exposure to simulated French LOCA conditions. Several mechanical, electrical, and physical-chemical condition monitoring techniques were used to investigate the degradation behavior of the cables. All the cables, except for the French PE cable, performed acceptably during the aging and LOCA simulations. In general, cable degradation at a given dose was highest for the lowest dose rate, and the amount of degradation decreased as the dose rate was increased.

  10. Connectivity structures local population dynamics: a long-term empirical test in a large metapopulation system.

    PubMed

    Castorani, Max C N; Reed, Daniel C; Alberto, Filipe; Bell, Tom W; Simons, Rachel D; Cavanaugh, Kyle C; Siegel, David A; Raimondi, Peter T

    2015-12-01

    Ecological theory predicts that demographic connectivity structures the dynamics of local populations within metapopulation systems, but empirical support has been constrained by major limitations in data and methodology. We tested this prediction for giant kelp Macrocystis pyrifera, a key habitat-forming species in temperate coastal ecosystems worldwide, in southern California, USA. We combined a long-term (22 years), large-scale (~500 km coastline), high-resolution census of abundance with novel patch delineation methods and an innovative connectivity measure incorporating oceanographic transport and source fecundity. Connectivity strongly predicted local dynamics (well-connected patches had lower probabilities of extinction and higher probabilities of colonization, leading to greater likelihoods of occupancy) but this relationship was mediated by patch size. Moreover, the relationship between connectivity and local population dynamics varied over time, possibly due to temporal variation in oceanographic transport processes. Surprisingly, connectivity had a smaller influence on colonization relative to extinction, possibly because local ecological factors differ greatly between extinct and extant patches. Our results provide the first comprehensive evidence that southern California giant kelp populations function as a metapopulation system, challenging the view that populations of this important foundation species are governed exclusively by self-replenishment. PMID:26909421

  11. Long-Term Reliability of SiGe/Si HBTs From Accelerated Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Bhattacharya, Pallab

    2001-01-01

    Accelerated lifetime tests were performed on double-mesa structure Si(0.7)Ge(0.3)/Si npn heterojunction bipolar transistors, grown by molecular beam epitaxy, in the temperature range of 175 C-275 C. The transistors (with 5x20 sq micron emitter area) have DC current gains approx. 40-50 and f(sub T) and f(sub max) of up to 22 GHz and 25 GHz, respectively. It is found that a gradual degradation in these devices is caused by the recombination enhanced impurity diffusion (REID) of boron atoms from the p-type base region and the associated formation of parasitic energy barriers to electron transport from the emitter to collector layers. This REED has been quantitatively modeled and explained, to the first order of approximation, and the agreement with the measured data is good. The mean time to failure (MTTF) of these devices at room temperature under 1.35 x 10(exp 4) A/sq cm current density operation is estimated from the extrapolation of the Arrhenius plots of device lifetime versus reciprocal temperature. The results of the reliability tests offer valuable feedback for SiGe heterostructure design in order to improve the long-term reliability of the devices and circuits made with them. Hot electron induced degradation of the base-emitter junction was also observed during the accelerated lifetime testing. In order to improve the HBT reliability endangered by the hot electrons, deuterium sintered techniques have been proposed. The preliminary results from this study show that a deuterium-sintered HBT is, indeed, more resistant to hot-electron induced base-emitter junction degradation.

  12. Long-term tracking of neutrally buoyant tracer particles in two-dimensional fluid flows

    NASA Astrophysics Data System (ADS)

    Pervez, M. S.; Solomon, T. H.

    1994-07-01

    An experimental technique has been developed to produce and to track neutrally buoyant particles in a two-dimensional fluid flow. The key aspect of the technique is the ability to track particles for extended intervals (over an hour), which is essential for quantitative studies of transport and mixing. The approach is composed of two stages. In the first stage, digital image processing hardware partially processes the images, reducing the data rate to 50 kbyte/s (typically) and allowing several hours of data to be stored on a conventional computer disk. In the second stage, programs extract particle trajectories from the reduced data. The approach is tested in an experiment on planetary-type flows in a rotating annulus. In an appendix, a technique is discussed for fabricating wax or crayon particles with arbitrary density.

  13. Low-flow frequency curves for selected long-term stream gaging stations in eastern United States

    USGS Publications Warehouse

    Hardison, Clayton H.; Martin, Robert O.R.

    1963-01-01

    Curves showing the magnitude and frequency of annual low flow at 85 streamgaging stations located in 17 States east and 5 States west of the Mississippi River have been smoothed and adjusted to one of four long-term periods. They are presented to show the similarity and dissimilarity of curves even in the same State and to provide background information for studies of the statistical properties of low-flow frequency curves and for studies of the relation between hydrologic environment and low flow. The results are presented as greatly reduced graphs to facilitate comparison and are summarized in tables from which expanded graphs can be plotted.

  14. Atomic oxygen ground-based accelerated tests of spacecraft materials and structures for long-term LEO missions

    NASA Astrophysics Data System (ADS)

    Chernik, Vladimir; Novikov, Lev; Smirnova, Tatyana; Shumov, Andrey

    Spacecraft materials are degradated during long-term low earth orbit (LEO) flight. The Internation Space Station (ISS) is planed to be prolonged the term of action up to 20-25 years. To specify so long life one requires a validation of spacecraft material behaviour conservation for the period. The LEO environment includes atomic oxygen (AO) destructive incident flow. The appropriate AO fluence is proposed to be as high as 10E22-10E23 atom O/sq cm. The simulative ground-based test is evident to be acceptable if its duration is not too long usually under several hundreds of hours. In that case the rate of the test acceleration exceeds 100-200. One way to accelerate test is to increase oxygen particles energy. We test materials under oxygen plasma beam, formed by a magnetoplasmadynamic accelerator, with the oxygen particle energy of 20 -30 eV. In this way we determine an AO effective fluence by a kapton equivalent technique. The beam varies from LEO incident flow by energy, flux and rates of the oxygen dissociation / ionization/ excitation. To evaluate the test adequacy we measured and compared with LEO data erosion yields of a number of polymer materials, applied on spacecraft external surfaces. There were: polyimide (kapton), polyamide (nylon), polyethylene, polyvinyl fluoride (tedlar), polysteren, polymethyl methacrylate, epoxy, polyethylene terephthalate (mylar), graphite. Their relative erosion yields, measured and normalized by polyimide in this way, practically coincide with the data of flight experiments on the ISS. The results ground to use our plasma mode for accelerated tests of spacecraft material durability for long-term LEO flights. We tested quite a number of polymer-based materials and structures usable on ISS and another LEO spacecrafts. The effective AO fluencies ran up to 3,5 10E22 atom O/sq cm corresponding to the ISS flight duration about 20 years. We studied material behaviors like mass and thickness losses, erosion yield, surface morphology

  15. Long term endurance test and contact degradation of CIGS solar cells

    NASA Astrophysics Data System (ADS)

    Ott, Thomas; Schönberger, Francillina; Walter, Thomas; Hariskos, Dimitrios; Kiowski, Oliver; Schäffler, Raymund

    2013-09-01

    CIGS is the most promising technology for thin-film solar cells with record efficiencies of 20.4 % on laboratory scale and 17.8 % aperture area efficiency on a 900 cm² module. Another important factor besides the cell efficiency is the reliability and long term stability of the manufactured modules, which can be assessed by accelerated ageing. In this contribution the accelerated ageing of CIGS mini modules has been investigated. Therefore, modules were dark annealed under dry heat conditions at different temperatures. During the endurance test a positive or negative bias was applied to the cells. In regular intervals the IV- and CV-characteristics were measured at room temperature. After an overall stress time of 3500 h the IV-characteristics were determined under different illumination conditions (intensity, spectral illumination). Our previous publications suggest a barrier at the back contact to explain the observed parameter drifts. This contribution is focused on the influence of different bias conditions during the endurance test on the generation of a back diode and on the change of the acceptor concentration. These parameter drifts have an impact on the open circuit voltage, fill factor and on the appearance of a cross over between dark and illuminated IV-characteristics. The interpretation of the observed parameter drifts was supported by SCAPS simulations based on the above mentioned back barrier model. As an outcome of the simulations signatures for the existence of a back barrier diode were established. IVmeasurements, temperature dependent Voc measurements and SunsVoc measurements are helpful means to detect such back diodes.

  16. Test of a motor theory of long-term auditory memory.

    PubMed

    Schulze, Katrin; Vargha-Khadem, Faraneh; Mishkin, Mortimer

    2012-05-01

    Monkeys can easily form lasting central representations of visual and tactile stimuli, yet they seem unable to do the same with sounds. Humans, by contrast, are highly proficient in auditory long-term memory (LTM). These mnemonic differences within and between species raise the question of whether the human ability is supported in some way by speech and language, e.g., through subvocal reproduction of speech sounds and by covert verbal labeling of environmental stimuli. If so, the explanation could be that storing rapidly fluctuating acoustic signals requires assistance from the motor system, which is uniquely organized to chain-link rapid sequences. To test this hypothesis, we compared the ability of normal participants to recognize lists of stimuli that can be easily reproduced, labeled, or both (pseudowords, nonverbal sounds, and words, respectively) versus their ability to recognize a list of stimuli that can be reproduced or labeled only with great difficulty (reversed words, i.e., words played backward). Recognition scores after 5-min delays filled with articulatory-suppression tasks were relatively high (75-80% correct) for all sound types except reversed words; the latter yielded scores that were not far above chance (58% correct), even though these stimuli were discriminated nearly perfectly when presented as reversed-word pairs at short intrapair intervals. The combined results provide preliminary support for the hypothesis that participation of the oromotor system may be essential for laying down the memory of speech sounds and, indeed, that speech and auditory memory may be so critically dependent on each other that they had to coevolve. PMID:22511719

  17. Test of a motor theory of long-term auditory memory

    PubMed Central

    Schulze, Katrin; Vargha-Khadem, Faraneh; Mishkin, Mortimer

    2012-01-01

    Monkeys can easily form lasting central representations of visual and tactile stimuli, yet they seem unable to do the same with sounds. Humans, by contrast, are highly proficient in auditory long-term memory (LTM). These mnemonic differences within and between species raise the question of whether the human ability is supported in some way by speech and language, e.g., through subvocal reproduction of speech sounds and by covert verbal labeling of environmental stimuli. If so, the explanation could be that storing rapidly fluctuating acoustic signals requires assistance from the motor system, which is uniquely organized to chain-link rapid sequences. To test this hypothesis, we compared the ability of normal participants to recognize lists of stimuli that can be easily reproduced, labeled, or both (pseudowords, nonverbal sounds, and words, respectively) versus their ability to recognize a list of stimuli that can be reproduced or labeled only with great difficulty (reversed words, i.e., words played backward). Recognition scores after 5-min delays filled with articulatory-suppression tasks were relatively high (75–80% correct) for all sound types except reversed words; the latter yielded scores that were not far above chance (58% correct), even though these stimuli were discriminated nearly perfectly when presented as reversed-word pairs at short intrapair intervals. The combined results provide preliminary support for the hypothesis that participation of the oromotor system may be essential for laying down the memory of speech sounds and, indeed, that speech and auditory memory may be so critically dependent on each other that they had to coevolve. PMID:22511719

  18. Long-term testing and evaluation of cathode components in a commercial aluminum cell

    SciTech Connect

    Gee, J.T.; Tucker, K.W; Joo, L.A.; Stewart, D.V.; Alcorn, T.; Tabereaux, A.

    1989-08-01

    Since 1886, essentially all primary aluminum has been produced in Hall-Heroult electrolytic cells which electrochemically reduce alumina to the metal in an energy/capital intensive process. Nearly five per cent of the electrical energy generated in the United States is consumed in this Hall-Heroult process, at the rate of 6--8 kwh/lb of aluminum produced. It has been in the aluminum industry's interest for the past several decades to utilize titanium diboride in some capacity as the cell cathode, either with conventional consumable carbon anodes or ultimately with nonconsumable, inert anodes. Eventual achievement of either or both of these goals will represent a technological breakthrough and make possible a significant reduction in the energy requirement to produce aluminum. The overall objective and achievement of this program was to better define the technical and economic viability of graphite-containing titanium diboride materials in low-cost shapes for use as cathodes in aluminum electrolytic cells as a precursor to subsequent demonstration and commercial application. Included are mathematical models for the prediction of cost-reducing cathode shapes, optimizing ratios of electrode areas, voltage reduction, and the effect on current efficiency from reduced anode-cathode distance. As part of the program, cathode shapes were produced using proprietary material processing technologies. Long-term commercial and medium-term pilot cell operations for data acquisition and cathode longevity determinations were completed, as were analyses of as-fabricated and as-tested cathodes, development of possible failure mechanisms, development of cathode holder/anode stops and an assessment of energy savings and technical/economic viability.

  19. Simulating soil C dynamics with EPIC: Model description and testing against long-term data

    SciTech Connect

    Izaurralde, R Cesar C.; Williams, Jimmy R.; Mcgill, William B.; Rosenberg, Norman J.; Quiroga Jakas, Maria C.

    2006-01-01

    Soil carbon sequestration (SCS) has emerged as a technology with significant potential to help stabilize atmospheric CO2 concentrations and thus reduce the threat of global warming. Methods and models are needed to evaluate and recommend SCS practices based on their effects on carbon dynamics and environmental quality. EPIC (Environment Policy Integrated Climate) is a widely used and tested model for simulating many agroecosystem processes including plant growth, crop yield, tillage, wind and water erosion, runoff, soil density, and leaching. Here we describe new C and N modules developed in EPIC built on concepts from the Century model to connect the simulation of soil C dynamics to crop management, tillage methods, and erosion processes. The added C and N routines interact directly with soil moisture, temperature, erosion, tillage, soil density, leaching, and translocation functions in EPIC. Equations were also added to describe the effects of soil texture on soil C stabilization. Lignin concentration is modeled as a sigmoidal function of plant age. EPIC was tested against data from a Conservation Reserve Program (CRP) 6-yr experiment at five sites in three U.S. Great Plains states and a 61-y long-term agronomic experiment in Canada. Mean Square Deviations (MSD) calculated for CRP sites were less than 0.01 kg C2 m2, except for one site where it reached 0.025 kg2 C2 m. MSD values in the 61-y experiment ranged between 0.047 and 0.077 kg C2 m2. In conclusion, the version of the EPIC model presented and tested here contains the necessary algorithms to simulate SCS and improve understanding of the interactions among soil erosion, C dynamics, and tillage. A strength of the model as tested is its ability to explain the variability in crop production, C inputs and SOC and N cycling over a wised range soil, cropping and climatic conditions over periods from 6 to 61 years. For example, at the Breton site over 61 years, EPIC accounted for 69% of the variability in grain

  20. Long-term explosive degassing and debris flow activity at West Mata submarine volcano

    NASA Astrophysics Data System (ADS)

    Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Caplan-Auerbach, J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T.-K.; Chadwick, W. W.

    2015-03-01

    West Mata is a 1200 m deep submarine volcano where explosive boninite eruptions were observed in 2009. The acoustic signatures from the volcano's summit eruptive vents Hades and Prometheus were recorded with an in situ (~25 m range) hydrophone during ROV dives in May 2009 and with local (~5 km range) moored hydrophones between December 2009 and August 2011. The sensors recorded low frequency (1-40 Hz), short duration explosions consistent with magma bubble bursts from Hades, and broadband, 1-5 min duration signals associated with episodes of fragmentation degassing from Prometheus. Long-term eruptive degassing signals, recorded through May 2010, preceded a several month period of declining activity. Degassing episodes were not recorded acoustically after early 2011, although quieter effusive eruption activity may have continued. Synchronous optical measurements of turbidity made between December 2009 and April 2010 indicate that turbidity maxima resulted from occasional south flank slope failures triggered by the collapse of accumulated debris during eruption intervals.

  1. Long-term agroecosystem research in the central Mississippi river basin: goodwater creek experimental watershed flow data.

    PubMed

    Baffaut, Claire; Sadler, E John; Ghidey, Fessehaie

    2015-01-01

    Flow monitoring in Goodwater Creek Experimental Watershed started in 1971 at three nested watersheds ranging from 12 to 73 km. Since then, runoff or stream flow has been measured at 14 plots, three fields, and 12 additional stream sites ranging from 0.0034 to 6067 km in the Central Mississippi River Basin. Long-term data sets are important to document the changes resulting from anthropogenic and natural drivers. The data set presented here documents discharge across a range of catchment sizes in an area known for its high runoff potential. It constitutes the flow database of the Central Mississippi River Basin site of the Long-Term Agricultural Research network. Like the other sites of this network, data are accessible through the STEWARDS web interface (). Here we (i) describe the data collection methods, (ii) document the data available at plot, field, and watershed scales, and (iii) provide the main characteristics of discharge. General characteristics of discharge per unit area for different cropping system management systems show that in this claypan soil setting, management and tillage of row crop systems do not affect surface flow during the growing season (April-October). Data from fields and stream sites show the dampening of peak flow values and lengthening of storm hydrographs caused by mixed land uses and longer times of concentration. Overall, stream flow accounts for a third of the precipitation, of which 80% is from surface runoff and 20% is from groundwater. PMID:25602317

  2. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands.

    PubMed

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming

    2016-08-01

    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future. PMID:27246456

  3. Tracing long-term vadose zone processes at the Nevada Test Site, USA

    PubMed Central

    Hunt, James R.; Tompson, Andrew F. B.

    2010-01-01

    The nuclear weapons testing programme of the USA has released radionuclides to the subsurface at the Nevada Test Site. One of these tests has been used to study the hydrological transport of radionuclides for over 25 years in groundwater and the deep unsaturated zone. Ten years after the weapon’s test, a 16 year groundwater pumping experiment was initiated to study the mobility of radionuclides from that test in an alluvial aquifer. The continuously pumped groundwater was released into an unlined ditch where some of the water infiltrated into the 200 m deep vadose zone. The pumped groundwater had well-characterized tritium activities that were utilized to trace water migration in the shallow and deep vadose zones. Within the near-surface vadose zone, tritium levels in the soil water are modelled by a simple one-dimensional, analytical wetting front model. In the case of the near-surface soils at the Cambric Ditch experimental site, water flow and salt accumulation appear to be dominated by rooted vegetation, a mechanism not included within the wetting front model. Simulation results from a two-dimensional vadose groundwater flow model illustrate the dominance of vertical flow in the vadose zone and the recharge of the aquifer with the pumped groundwater. The long-time series of hydrological data provides opportunities to understand contaminant transport processes better in the vadose zone with an appropriate level of modelling. PMID:21785525

  4. The design, fabrication, and testing of WETF high-quality, long-term-storage, secondary containment vessels

    SciTech Connect

    Kane J. Fisher

    2000-03-01

    Los Alamos National Laboratory's Weapons Engineering Tritium Facility (WETF) requires secondary containment vessels to store primary tritium containment vessels. The primary containment vessel provides the first boundary for tritium containment. The primary containment vessel is stored within a secondary containment vessel that provides the secondary boundary for tritium containment. WETF requires high-quality, long-term-storage, secondary tritium containment vessels that fit within a Mound-designed calorimeter. In order to qualify the WETF high-quality, long-term-storage, secondary containment vessels for use at WETF, steps have been taken to ensure the appropriate design, adequate testing, quality in fabrication, and acceptable documentation.

  5. Long-term memory: disruption by inhibitors of protein synthesis and cytoplasmic flow

    SciTech Connect

    Flood, J.F.; Landry, D.W.; Bennett, E.L.; Jarvik, M.E.

    1981-01-01

    Colchicine (60 ..mu..g/kg), an inhibitor of axoplasmic transport, administered subcutaneously to mice has no detectable effect on retention when given shortly after active avoidance training, nor did a pertaining injection of anisomycin (ANI) have an amnesic effect. However, when ANI was administered shortly prior to training and colchicine was administered after training, retention performance was impaired. The amnesic effect was dependent on the time at which colchicine was administered. The amnesic effect was also obtained when ANI was combined with either vinblastine (6 ..mu..g/kg) or podophyllotoxin (3 ..mu..g/kg), drugs that inhibit axoplasmic transport. Intracerebral injections of colchicine (60 ng to 60 pg) caused amnesia in subjects pretreated with ANI, but not in subjects pretreated with saline. Lumicolchicine, an isomer of colchicine, which has similar central nervous system effects but has a low binding affinity for microtubule protein, did not impair retention in ANI pretreated mice. It is suggested that axonal transport of recently synthesized protein is required for long-term memory storage.

  6. A test of our society: how and for whom we finance long-term care.

    PubMed

    Merrill, J

    1992-01-01

    Financing long-term care remains an issue of great national interest, but little action. This lack of action is due to a lack of consensus regarding both what we mean by long-term care and what roles the private and public sectors should play. Different solutions have been offered, some focusing on the public sector and others on the private. The reality is that financing the needed care will require participation of both sectors, as well as a redefinition of their roles that makes them complementary rather than competitive, as is now the case. This partnership can take many forms, but must, at a minimum, reflect an explicit societal commitment to what our population is entitled to with respect to long-term care; develop the infrastructure that meets the total--as opposed to only the medical--needs of the population; and make more efficient use of the resources that can be brought to bear on the problem. PMID:1612718

  7. Reversed portal flow: Clinical influence on the long-term outcomes in cirrhosis

    PubMed Central

    Kondo, Takayuki; Maruyama, Hitoshi; Sekimoto, Tadashi; Shimada, Taro; Takahashi, Masanori; Yokosuka, Osamu

    2015-01-01

    AIM: To elucidate the natural history and the longitudinal outcomes in cirrhotic patients with non-forward portal flow (NFPF). METHODS: The present retrospective study consisted of 222 cirrhotic patients (120 males and 102 females; age, 61.7 ± 11.1 years). The portal hemodynamics were evaluated at baseline and during the observation period using both pulsed and color Doppler ultrasonography. The diameter (mm), flow direction, mean flow velocity (cm/s), and mean flow volume (mL/min) were assessed at the portal trunk, the splenic vein, the superior mesenteric vein, and the collateral vessels. The average values from 2 to 4 measurements were used for the data analysis. The portal flow direction was defined as follows: forward portal flow (FPF) for continuous hepatopetal flow; bidirectional flow for to-and-fro flow; and reversed flow for continuous hepatofugal flow. The bidirectional flow and the reversed flow were classified as NFPF in this study. The clinical findings and prognosis were compared between the patients with FPF and those with NFPF. The median follow-up period was 40.9 mo (range, 0.3-156.5 mo). RESULTS: Twenty-four patients (10.8%) demonstrated NFPF, accompanied by lower albumin level, worse Child-Pugh scores, and model for end-stage liver disease scores. The portal hemodynamic features in the patients with NFPF were smaller diameter of the portal trunk; presence of short gastric vein, splenorenal shunt, or inferior mesenteric vein; and advanced collateral vessels (diameter > 8.7 mm, flow velocity > 10.2 cm/s, and flow volume > 310 mL/min). The cumulative incidence rates of NFPF were 6.5% at 1 year, 14.5% at 3 years, and 23.1% at 5 years. The collateral vessels characterized by flow velocity > 9.5 cm/s and those located at the splenic hilum were significant predictive factors for developing NFPF. The cumulative survival rate was significantly lower in the patients with NFPF (72.2% at 1 year, 38.5% at 3 years, 38.5% at 5 years) than in those with forward

  8. From Gaged to Ungaged- Predicting Long-term Environmental Flows, and Ecosystems Responses.

    NASA Astrophysics Data System (ADS)

    Sengupta, A.; Adams, S. K.; Stein, E. D.; Mazor, R.; Bledsoe, B. P.

    2015-12-01

    Modern management needs, such as water supply, quality, and ecosystem protection place numerous demands on instream flows. Many regions are interested in developing numeric flow criteria as a way of ensuring maintenance of flow patterns that protect biological resources while meeting other demands. Developing flow criteria requires the capacity to generate reliable time series of the daily flow at any stream reach of interest and to relate flow patterns to biological indicators of stream health. Most stream reaches are not gaged, and it is impractical to develop detailed models for all reaches where flow alteration needs to be evaluated. We present a novel mechanistic approach to efficiently predict flows and flow alteration at all ungaged stream locations within a region of interest. We used an "ensemble approach" whereby a series of regionally representative models were developed and calibrated. New sites of interest are assigned to one of the ensemble models based on similarity of catchment properties. For southern California, we selected 43 gaged sites representing the range of geomorphology, and watershed characteristics of streams in the region. For each gaged site, we developed a hydrologic model (HEC-HMS) to predict daily flows for a period representing dry, wet and normal precipitation. The final goal is to relate flow alterations to ecological responses, the models were calibrated to three separate performance metrics that reflect conditions important for instream biological communities- proportion of low flow days, flashiness and Nash Sutcliffe efficiency for overall model performance. We cross-validated the models using a "jack-knife" approach. Models were assigned to novel 840 bioassessment sites based on the results of a Random Forest model that identified catchment properties that most affected the runoff patterns. Daily flow data for existing and "reference conditions" was simulated for a 23-year period for current and reference (undeveloped

  9. Analysis on the Long Term Effect of Trial Test Road Constructed on Batu Pahat Soft Clay (BPSC) at Recess UTHM

    NASA Astrophysics Data System (ADS)

    Idrus, M. M. M.; Edayu, A. E.; Adnan, Z.; Ismail, B.

    2016-07-01

    The reinforcement used in soil for construction of roads on the soft clay is very important as it will determine the level of service of the road after it was built. Damage or defects on the road surface to be an indicator of the level of the road has dropped and shows the deformation of the road. For this research, an analysis has carried out on the long-term effect of trial test road constructed on Batu Pahat Soft Clay (BPSC) at RECESS UTHM. Through this research, the reinforcement using Rawell Geosynthetic Clay Liner (RGCL) was the best with the stability is 14964 N, a low flow is 2.69mm, stiffness modulus is 1766 MPa, the peak load is 739.4 N and a lower horizontal deformation which is 1.71 µm compared Woven Geotextile section and section without geotextile [1] [9]. In terms of deformation can be seen clearly from physical observations that section without geotextile suffered significant damage than others. Settlement of road can also be analyzed by a longitudinal section that plotted based on the result of leveling work. After that, settlements are more visible way on the right side of the road trial. Through lab tests conducted, it indicate that the coring samples obtained from sites of each section meets the specifications set by the Jabatan Kerja Raya (JKR) in terms of stability, flow and stiffness [1]. Through this study, a trial road built on soft soil can be used as a test site because of the uniqueness of these roads which has three different types of reinforcements.

  10. Developing a Framework for Testing Distributed Hydrologic Models at the Catchment Scale - Examples of Test Model Runs for Event Based and Long Term Simulations

    NASA Astrophysics Data System (ADS)

    Cristea, N. C.; Kampf, S. K.; Mirus, B. B.; Loague, K.; Burges, S. J.

    2008-12-01

    We develop a testing framework for distributed hydrologic models at the catchment scale using the hypothetical reality concept. The hypothetical reality, considered an error-free hydrologic response modeled after the 10.5-ha Tarrawarra catchment in Australia, is generated using the sophisticated Integrated Hydrology Model (InHM) representing fully coupled 3D variably saturated subsurface and 2D surface flow with finite-element discretization. The hypothetical realty consists in a data set composed of two subsets designed to test long-term and event-based behavior of the test model. The first subset, a long term data set, comprises an 11-year variable time step time series of hydrograph output and head and saturation levels at 55 observation nodes as well as daily snapshots of head and saturation levels at all nodes in the domain. The second subset, short term data set, has the same type of output, but the domain snapshots are at a much finer time scale, every half hour for the selected rain events. Both data sets were obtained with the same InHM configuration but different output time steps. We use MODHMS (HydroGeoLogic, Inc.), a MODFLOW-based code that solves Richards equation for the 3-D variably saturated subsurface flow and the diffuse wave approximation 2D overland flow with finite differences in a coupled approach as the test model. We present examples of model testing scenarios with variations in spatial discretization, initial conditions, and representation of hydrologic processes. Future work includes testing of model parameters and soil characteristics, with the test model running first without any calibration and then with calibration against the hypothetical reality.

  11. Analysis of long-term trends in flow from a Large Spring Complex in northern Florida

    USGS Publications Warehouse

    Grubbs, Jack W.

    2011-01-01

    Nonparametric regression analysis of historic flow and rainfall data was used to estimate declining flows in a river draining a large spring complex in northern Florida, USA. The analysis indicated that flow declined by an estimated 23 percent from 1900 to 2009. The rate of decline appeared to increase over time, from about 0.8 cubic foot per second per year during the period from 1930-1970, to about 1.1 cubic feet per second per year over the period from 1970-2009. The estimated decline for the period prior to 1980 is consistent with evidence indicating groundwater withdrawals to the east of the study area have diverted groundwater that formerly flowed toward the Ichetucknee River under predevelopment conditions.

  12. Long-term methanol vehicle test program. Final subcontract report, 1 November 1992--1 February 1995

    SciTech Connect

    Jones, J.C.; Maxwell, T.T.

    1995-09-01

    Work was sperformed to determine effects of methanol fuel on engine performance and exhaust emissions during long-term use in a 1988 Chevrolet Corsica. Engine wear, gasket performance, fuel economy, emissions level, oil consumption, and overall vehicle performance were monitored over 22,000 miles. Baselines were established at the beginning for comparison: engine was disassembled, bearing/ring clearances and cam profiles were measured. Higher flow rate fuel injectors from AC Rochester were installed and the computer system calibrated for M100 fuel. The vehicle durability test increased oil consumption by 26% under cold-start conditions, 9% under hot start. Oil consumption under hot start was higher than under cold start by as much as 56%; effect of component temperatures on oil viscosity appears to be the cause. It is recommended that oil consumption of a gasoline-fueled vehicle be measured in order to normalize the effect of methanol operation on oil consumption, and to study the effect of steady-state and transient conditions on oil consumption.

  13. Femoral head blood flow in long-term steroid therapy: study of rabbit model

    SciTech Connect

    Wang, G.J.; Hubbard, S.L.; Reger, S.I.; Miller, E.D.; Stamp, W.G.

    1983-12-01

    Using a rabbit model, previous studies showed steroid-induced hyperlipidemia with subsequent fatty embolization of the subchondral arteries and hypertrophy of the marrow fat cells, followed by elevation of femoral head pressure from the normal level of 25 cm to nearly 60 cm H2O after eight weeks of treatment. This has led us to believe that pressure changes lead to decreased blood flow in the femoral head. In our study of 22 New Zealand white adult rabbits, weighing an average of 4.0 kg, 14 received a weekly dose of 12.45 mg of methylprednisolone (Depo-Medrol), and eight served as control. Femoral head blood flow was established using the radioactive microsphere technique. Control and cortisone-treated rabbits had femoral head blood flow measured 6, 8 and 10 weeks after treatment. The average blood flow in the control femoral heads averaged 0.2039 +/- 0.076 ml/min/gm, with no difference in the left side and the right side. In the treated group, the average blood flow at ten weeks was 0.162 +/- 0.039 ml/min/gm on the right and 0.164 +/- 0.037 ml/min/gm on the left, which was significantly different. This is parallel to unpredictable clinical findings in human beings.

  14. Femoral head blood flow in long-term steroid therapy: study of rabbit model.

    PubMed

    Wang, G J; Hubbard, S L; Reger, S I; Miller, E D; Stamp, W G

    1983-12-01

    Using a rabbit model, previous studies showed steroid-induced hyperlipidemia with subsequent fatty embolization of the subchondral arteries and hypertrophy of the marrow fat cells, followed by elevation of femoral head pressure from the normal level of 25 cm to nearly 60 cm H2O after eight weeks of treatment. This has led us to believe that pressure changes lead to decreased blood flow in the femoral head. In our study of 22 New Zealand white adult rabbits, weighing an average of 4.0 kg, 14 received a weekly dose of 12.45 mg of methylprednisolone (Depo-Medrol), and eight served as control. Femoral head blood flow was established using the radioactive microsphere technique. Control and cortisone-treated rabbits had femoral head blood flow measured 6, 8 and 10 weeks after treatment. The average blood flow in the control femoral heads averaged 0.2039 +/- 0.076 ml/min/gm, with no difference in the left side and the right side. In the treated group, the average blood flow at ten weeks was 0.162 +/- 0.039 ml/min/gm on the right and 0.164 +/- 0.037 ml/min/gm on the left, which was significantly different. This is parallel to unpredictable clinical findings in human beings. PMID:6648615

  15. MODELING LONG-TERM NITRATE BASE-FLOW LOADING FROM TWO AGRICULTURAL WATERSHEDS

    EPA Science Inventory

    Nitrate contamination of ground water from agricultural practices may be contributing to the eutrophication of the Chesapeake Bay, degrading water quality and aquatic habitats. Groundwater flow and nitrate transport and fate are modeled, using MODFLOW and MT3D computer models, in...

  16. Greenhouse Gases in the South Atlantic: Testing and Automation of Instrumentation for Long-Term Monitoring

    NASA Astrophysics Data System (ADS)

    Lowry, D.; Fisher, R.; Sriskantharajah, S.; Lanoisellé, M.; Etchells, A.; Manning, A.; Nisbet, E.

    2009-04-01

    Understanding ocean uptake of atmospheric CO2 by the Southern Ocean is important for modelling of future global warming scenarios, particularly since it was recently proposed that this sink was reducing (Le Quéré, et al., 2007). To help our understanding of this problem a new project aims to flask sample air from 5 South Atlantic sites and set up continuous monitoring at the 2 most accessible of these: Ascension Island and the Falklands. Flask sample measurements will include CO2 and CH4 mixing ratios and the ^13C measurement of both of these gases using the rapid continuous flow trace gas analysis system at Royal Holloway, University of London (RHUL). Routine precisions are ±0.03 per mil and ±0.05 per mil for CO2 and CH4, respectively (Fisher et al., 2006). A time series of ^13C in CH4 was maintained for Ascension Island from 2000-2005 and a time series for methane isotopes commenced for the Falkland Islands in autumn 2007. To meet the continuous monitoring requirements of the new project, three Picarro G1301 CO2 / CH4 / H2O Cavity Ring Down Spectrometers (CRDS) were installed at RHUL in October 2008 for testing, calibration and the development of an automated air inlet system suitable for analysis of calibration gases at the remote sites. Initial testing included calibration with NOAA calibrated and target gases, validation of the Picarro-defined H2O-correction of CO2, and derivation of an H2O-correction for CH4. Continuing checks on the H2O correction are made by having 2 instruments side-by-side taking air from the same inlet, but one having a combined Nafion / Mg-perchlorate drying system that utilizes the analysis system exhaust gas for the reverse flow through the Nafion and maintains water-levels at 0.05% for more than 2 weeks. These instruments are connected to the same air inlet as a GC measuring CH4 mixing ratio and a LiCor 6252 measuring CO2 mixing ratio at 30-minute and 1-minute intervals respectively. The third CRDS instrument is connected to a

  17. Simulation of long-term debris flow sediment transport based on a slope stability and a debris flow routing model

    NASA Astrophysics Data System (ADS)

    Müller, T.; Hoffmann, T.

    2012-04-01

    Debris flows play a crucial role in the coupling of hillslope-sediment sources and channels in mountain environments. In most landscape evolution models (LEMs), the sediment transport by debris flows is (if at all) often represented by simple empirical rules. This generally results from the mismatch of the coarse resolution of the LEMs and the small scale impacts of debris flow processes. To extend the accuracy and predictive power of LEMs, either a higher resolution of LEMs in combination with process-based debris flow models or a better parametrisation of subpixel scale debris flow processes is necessary. Furthermore, the simulation of sediment transport by debris flows is complicated by their episodic nature and unknown factors controlling the frequency and magnitude of events. Here, we present first results using a slope stability model (SINMAP) and an event-based debris flow routing model (SCIDDICA-S4c) to simulate the effects of debris flows in LEMs. The model was implemented in the XULU modelling platform developed by the Department of Computer Science at the University of Bonn. The combination of the slope stability model and the event-based routing and mass balance model enables us to simulate the triggering and routing of debris flow material through the iteration of single events over several thousand years. Although a detailed calibration and validation remains to be done, the resulting debris flow-affected areas in a test elevation model correspond well with data gained from a geomorphological mapping of the corresponding area, justifying our approach. The increased computation speed allows to run high resolution LEM in convenient short time at relatively low cost. This should encourage the development of more detailed LEMs, in which process-based models should be incorporated.

  18. Improving Long-term Post-wildfire hydrologic simulations using ParFlow

    NASA Astrophysics Data System (ADS)

    Lopez, S. R.; Kinoshita, A. M.

    2015-12-01

    Wildfires alter the natural hydrologic processes within a watershed. After vegetation is burned, the combustion of organic material and debris settles into the soil creating a hydrophobic layer beneath the soil surface with varying degree of thickness and depth. Vegetation regrowth rates vary as a function of radiative exposure, burn severity, and precipitation patterns. Hydrologic models used by the Burned Area Emergency Response (BAER) teams use input data and model calibration constraints that are generally either one-dimensional, empirically-based models, or two-dimensional, conceptually-based models with lumped parameter distributions. These models estimate runoff measurements at the watershed outlet; however, do not provide a distributed hydrologic simulation at each point within the watershed. This work uses ParFlow, a three-dimensional, distributed hydrologic model to (1) correlate burn severity with hydrophobicity, (2) evaluate vegetation recovery rate on water components, and (3) improve flood prediction for managers to help with resource allocation and management operations in burned watersheds. ParFlow is applied to Devil Canyon (43 km2) in San Bernardino, California, which was 97% burned in the 2003 Old Fire. The model set-up uses a 30m-cell size resolution over a 6.7 km by 6.4 km lateral extent. The subsurface reaches 30 m and is assigned a variable cell thickness. Variable subsurface thickness allows users to explicitly consider the degree of recovery throughout the stages of regrowth. Burn severity maps from remotely sensed imagery are used to assign initial hydrophobic layer parameters and thickness. Vegetation regrowth is represented with satellite an Enhanced Vegetation Index. Pre and post-fire hydrologic response is evaluated using runoff measurements at the watershed outlet, and using water component (overland flow, lateral flow, baseflow) measurements.

  19. Startup and long term operation of enhanced biological phosphorus removal in continuous-flow reactor with granules.

    PubMed

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-07-01

    The startup and long term operation of enhanced biological phosphorus removal (EBPR) in a continuous-flow reactor (CFR) with granules were investigated in this study. Through reducing the settling time from 9min to 3min gradually, the startup of EBPR in a CFR with granules was successfully realized in 16days. Under continuous-flow operation, the granules with good phosphorus and COD removal performance were stably operated for more than 6months. And the granules were characterized with particle size of around 960μm, loose structure and good settling ability. During the startup phase, polysaccharides (PS) was secreted excessively by microorganisms to resist the influence from the variation of operational mode. Results of relative quantitative PCR indicated that granules dominated by polyphosphate-accumulating organisms (PAOs) were easier accumulated in the CFR because more excellent settling ability was needed in the system. PMID:27085149

  20. Full-scale demonstration of Low-NO{sub x} Cell{trademark} Burner retrofit: Long-term testing

    SciTech Connect

    Eckhart, C.F.; DeVault, R.F.; Kung, S.C.

    1994-03-01

    The Low-NO{sub x} Cell{trademark} Burner (LNCB) concept was developed by Babcock & Wilcox (B&W) to effectively reduce the NO{sub x} emissions from pulverized-coal-fired boilers equipped with cell burners. These boilers were built mostly in the mid to late 1960s. Small (6-million Btu/hr) and intermediate (100-million Btu/hr) prototype versions of the concept were developed jointly by B&W and the Electric Power Research Institute (EPRI) during the mid-to-late 1980s. The design of B&W LNCBs allows direct replacements of the originally installed cell burners without pressure-part modifications. During this US Department of Energy (DOE) Clean Coal III program, Dayton Power and Light Company (DP&L) served as the host utility using its J.M. Stuart Station Unit {number_sign}4 (JMSS 4) for the first full-scale LNCB demonstration. This unit has a rated output capacity of 605 MW{sub e}. After the LNCB retrofit and burner optimization contract phases in late 1991, JMSS 4 underwent a long- term (nine months) test period from July 1992 to March 1993. The objective of this test was to determine the overall performance of this boiler after the LNCB retrofit. The long-term test involved determinations of the boiler emission performance and evaluations of waterwall corrosion potential, as well as a study of the overall operability of the LNCB system. Specific tasks performed during this long-term test include: (1) laboratory corrosion study; (2) field corrosion panel study; (3) in-furnace gas species probing; and (4) boiler emissions performance study. This report summarizes the long- term test results.

  1. Long-term mechanical life testing of polymeric post insulators for distribution and a comparison to porcelain

    SciTech Connect

    Cherney, E.A. )

    1988-07-01

    The paper presents the results and analyses of long-term cantilever strength tests on polymeric line post insulators. The time-to-failure data for static cantilever loads are represented by the Weibull distribution. The life distribution, obtained from the maximum likelihood estimates of the accelerated failure times, fits an exponential model. An extrapolation of the life distribution to normal loads provides an estimate of the strength rating and mechanical equivalence to porcelain line post insulators.

  2. Methodology for predicting long-term fuel-cell performance from short-term testing. Final technical report

    SciTech Connect

    Patel, D.; Farooque, M.; Maru, H.; Ware, C.

    1981-08-01

    The objective of this program was to develop a methodology for predicting long-term fuel cell performance from short-term testing, utilizing a perturbation testing technique. The technique applies small changes of predetermined levels in a predetermined sequence to the operating variables such that the decay mechanisms are not altered. This technique was tested on the phosphoric acid fuel cell (PAFC), because this technology is approaching a mature stage. The initial series of perturbation tests appear to be reasonably successful and a methodology is now available for further refinements. The progress made during the study is detailed.

  3. Prospective analysis of long term control of mild hypertension on cerebral blood flow

    SciTech Connect

    Meyer, J.S.; Rogers, R.L.; Mortel, K.F.

    1985-11-01

    A group of 12 otherwise normal elderly volunteers (mean age = 69.8 years), were detected to have mild hypertension. Cerebral blood flow (CBF) values were measured using 133Xe inhalation method prior to initiating medical treatment and repeated at 6, 12, 24 and 36 months after BP was adequately controlled and restored to normal (below 150/90). Results indicate that CBF values increased markedly during follow-up intervals at 6, 12 and 24 months but not at 36 months. Hypertension is known to be a risk factor for stroke and 4 of the 12 subjects subsequently developed symptoms of cerebrovascular disease (stroke, multi-infarct dementia or transient ischemic attacks) despite control of hypertension. Analyses separating asymptomatic and symptomatic groups indicated that the eight asymptomatic patients continued to maintain increased CBF levels throughout the entire three year interval, whereas the 4 symptomatic patients developed declines in CBF which began, and progressively decreased below the initial pretreatment values, during the second and third years.

  4. Enhanced long-term nitrogen removal and its quantitative molecular mechanism in tidal flow constructed wetlands.

    PubMed

    Zhi, Wei; Yuan, Li; Ji, Guodong; He, Chunguang

    2015-04-01

    Tidal flow constructed wetlands (TF CWs) have recently been studied as a sustainable technology to achieve enhanced nitrogen removal; however, the underlying mechanisms responsible for removing ammonium (NH4(+)) and nitrate (NO3(-)) have not been compared and quantified at the molecular level (genes) in controlled TF CWs. In this study, two TF CWs T1 (treating NH4(+) wastewater) and T2 (treating NO3(-) wastewater) achieved high removal efficiencies for chemical oxygen demand (COD, 92 ± 2.7% and 95 ± 2.4%, respectively), NH4(+)/NO3(-) (76 ± 3.9% and 97 ± 2.2%, respectively), and total nitrogen (TN, 81 ± 3.5% and 93 ± 2.3%, respectively). Combined analyses revealed that the presence of simultaneous nitrification, anammox, and denitrification processes and the coupling of dissimilatory nitrate reduction to ammonium, ammonia oxidation, and anammox were the primary reason accounted for the robust treatment performance in T1 and T2, respectively. Results from stepwise regression analysis suggested that the NH4(+) removal rate in T1 was collectively controlled by amoA, nxrA, and anammox, while the NO3(-) removal rate in T2 was governed by nxrA and narG gene. PMID:25781063

  5. Long-term testing and properties of acrylic for the Daya Bay antineutrino detectors

    NASA Astrophysics Data System (ADS)

    Krohn, M.; Littlejohn, B. R.; Heeger, K. M.

    2012-08-01

    The Daya Bay reactor antineutrino experiment has recently measured the neutrino mixing parameter sin22θ13 by observing electron antineutrino disappearance over kilometer-scale baselines using six antineutrino detectors at near and far distances from reactor cores at the Daya Bay nuclear power complex. Liquid scintillator contained in transparent target vessels is used to detect electron antineutrinos via the inverse beta-decay reaction. The Daya Bay experiment will operate for about five years yielding a precision measurement of sin22θ13. We report on long-term studies of poly(methyl methacrylate) known as acrylic, which is the primary material used in the fabrication of the target vessels for the experiment's antineutrino detectors. In these studies, acrylic samples are subjected to gaseous and liquid environmental conditions similar to those experienced during construction, transport, and operation of the Daya Bay acrylic target vessels and detectors. Mechanical and optical stability of the acrylic as well as its interaction with detector liquids is reported.

  6. The Role of Debris Flows in Long-term Denudation and Landscape Evolution in the central Appalachians

    NASA Astrophysics Data System (ADS)

    Eaton, L. S.

    2004-12-01

    Four major storms spanning a 46 year period from 1949 to 1995 that triggered debris flows in the Virginia-West Virginia Appalachians provided new insights into the role of high-magnitude, low-frequency storm events in long-term denudation and landscape evolution in mountainous terrain. Storm denudation measured in five Blue Ridge Mountain drainage basins (mean=3.7 cm) was approximately an order of magnitude greater compared to four basins located in the mountains of the Valley and Ridge province (mean=0.2cm). This difference is probably the result of higher storm rainfall from the Blue Ridge storms. Long-term (103 yrs) denudation rates were estimated using several lines of evidence, including 1) studies of the volume of sediment deposited in, or offshore of, the Atlantic Coastal Plain; 2) findings of parallel rates of continental uplift and denudation; and 3) historic sediment-load data. Using these estimates and subtracting the denudation attributed to chemical load, the mechanical denudation rate of the central Blue Ridge is approximated as 2.4 cm/k.y. Whereas debris flows recur at a frequency of approximately one event each three years somewhere in the unglaciated terrain of the Appalachians, the return interval is much greater when only individual mountainous basins are considered. Radiocarbon dating of debris-flow deposits in mountainous first- and second-order river basins of the Blue Ridge indicates a debris-flow return interval of not more than 2000 to 4000 yr. These data on debris flow frequency, combined with measurements of storm-induced upland basin denudation, suggests that approximately half of the long-term denudation from mechanical load occurs episodically by debris-flows. Although floods of moderate magnitude are largely responsible for mobilizing sediment in low-gradient streams, the data suggest that high-magnitude, low-frequency events are the most significant component in delivering coarse-grained colluvium from mountainous hollows and

  7. Long-term flow/chemistry feedback in a porous medium with heterogenous permeability: Kinetic control of dissolution and precipitation

    SciTech Connect

    Bolton, E.W.; Lasaga, A.C.; Rye, D.M.

    1999-01-01

    The kinetics of dissolution and precipitation is of central importance to understanding the long-term evolution of fluid flows in crustal environments, with implications for problems as diverse as nuclear waste disposal and crustal evolution. The authors examine the dynamics of such evolution for several geologically relevant permeability distributions (models for en-echelon cracks, an isolated sloping fractured zone, and two sloping high-permeability zones that are close enough together to interact). Although the focus is on a simple quartz matrix system, generic features emerge from this study that can aid in the broader goal of understanding the long-term feedback between flow and chemistry, where dissolution and precipitation is under kinetic control. Examples of thermal convection in a porous medium with spatially variable permeability reveal features of central importance to water-rock interaction. After a transient phase, an accelerated rate of change of porosity may be used with care to decrease computational time, as an alternative to the quasi-stationary state approximation (Lichtner, 1988). Kinetic effects produce features not expected by traditional assumptions made on the basis of equilibrium, for example, that cooling fluids are oversaturated and heating fluids are undersaturated with respect to silicic acid equilibrium. Indeed, the authors observe regions of downwelling oversaturated fluid experiencing heating and regions of upwelling, yet cooling, undersaturated fluid. When oscillatory convection is present, the amplitudes of oscillation generally increase with time in near-surface environments, whereas amplitudes tend to decrease over long times near the heated lower boundary. The authors examine the scaling behavior of characteristic length scales, of terms in the solute equation, and of the typical deviation from equilibrium, each as a function of the kinetic rate parameters.

  8. Laboratory testing on the removal of the veterinary antibiotic doxycycline during long-term liquid pig manure and digestate storage.

    PubMed

    Widyasari-Mehta, Arum; Suwito, Hanna Resti Kartika Ayu; Kreuzig, Robert

    2016-04-01

    The veterinary antibiotic doxycycline (DOXY) is today frequently applied in conventional pig husbandry for the control of respiratory diseases. After the treatment, pigs excrete major amounts of DOXY as the unchanged active substance. Thus, DOXY residues were found in liquid manures and digestates of biogas plants at concentrations of mg kg(-1) dry weight. In order to assess the impact of field applications of contaminated manures and digestates on the entry of DOXY residues into arable and grassland soils, thorough information about the removal of DOXY during long-term storage of farm fertilizers is required. Since this aspect has been only less investigated for manures but not for digestates, first long-term storage simulation tests were performed at laboratory scale. Within the 170-d incubation periods under strictly anaerobic conditions, doxycycline was removed in liquid pig manure by 61% and in digestate by 76%. The calculated half-lives of 120 d and 91 d thus emphasized the persistence of doxycycline in both matrices. Due to the substance specific properties of DOXY, this removal was caused neither by mineralization, epimerization nor biotransformation. According to the high affinity of DOXY to manure and digestate solids, however, the formation of non-extractable residues has to be taken into account as the predominant concentration determining process. This was indicated by the sequential extraction procedure applied. Hence, these results confirmed that a full removal capacity for doxycycline cannot be reached through the long-term storage of farm fertilizers. PMID:26855219

  9. Evaluating long-term trends in mean- and high- river flows using a network of reference stations in Ireland

    NASA Astrophysics Data System (ADS)

    Wilby, R. L.; Murphy, C.; Harrigan, S.; Hall, J.

    2012-12-01

    This paper describes the development of a reference hydrometric network for Ireland established primarily for the detection of climate driven trends in mean and high river flows. Thirty-five stations were identified for inclusion in the network plus a further 8 from the UK Benchmark Network. Their average record length is 40 years with a minimum of 28 and maximum of 63 years. Time series were derived for eight river flow indices: annual and seasonal mean flows and the annual maximum 1-, 10- and 30-day flows. Mann Kendall and Theil Sen statistics were applied to all indices using fixed and variable start/end dates. Trends in the winter mean are found to be highly dependent on the chosen period of analysis with the longest records showing increased flows. Contrary to expectations (of regional climate change scenarios), increases are also evident for long-term summer mean flows. High flow metrics exhibit positive and persistent trends that are less affected by inter-annual variability and period of record. Overall, there is strong spatial coherence in these patterns of change, linked to temporal variations in precipitation. Our results highlight the dangers of using conventional fixed periods such as 1961-1990 for trend detection, recognising that there is always a trade-off between record length, density of the network, and geographic coverage. Furthermore, outliers at the beginning of the record can be an artefact of the original motivation for installing the gauging station(s). In this case, water resource concerns during a markedly dry period in the mid-1970s favour positive trends over subsequent decades. Future work will focus on detection times for climate change signals and the identification of sentinel sites for discerning early signs of anthropogenic climate change across Ireland. Broader lessons for monitoring and detection of anthropogenic climate change signals will also be distilled.

  10. Long-Term Testing of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2013 Progress Report

    SciTech Connect

    Gerber, Mark A.; Gray, Michel J.; Thompson, Becky L.

    2013-09-23

    The U.S. Department of Energy’s Pacific Northwest National Laboratory has been conducting research since 2005 to develop a catalyst for the conversion of synthesis gas (carbon monoxide and hydrogen) into mixed alcohols for use in liquid transportation fuels. Initially, research involved screening possible catalysts based on a review of the literature, because at that time, there were no commercial catalysts available. The screening effort resulted in a decision to focus on catalysts containing rhodium and manganese. Subsequent research identified iridium as a key promoter for this catalyst system. Since then, research has continued to improve rhodium/manganese/iridium-based catalysts, optimizing the relative and total concentrations of the three metals, examining baseline catalysts on alternative supports, and examining effects of additional promoters. Testing was continued in FY 2013 to evaluate the performance and long-term stability of the best catalysts tested to date. Three tests were conducted. A long-term test of over 2300 hr duration at a single set of operating conditions was conducted with the best carbon-supported catalyst. A second test of about 650 hr duration at a single set of operating conditions was performed for comparison using the same catalyst formulation on an alternative carbon support. A third test of about 680 hr duration at a single set of operating conditions was performed using the best silica-supported catalyst tested to date.

  11. Tests of US rock salt for long-term stability of CAES reservoirs

    SciTech Connect

    Gehle, R.M.; Thoms, R.L.

    1986-01-01

    This is a report on laboratory tests to assess the effects of compressed air energy storage (CAES) on rock salt within the US. The project included a conventional laboratory test phase, with triaxial test machines, and a bench-scale test phase performed in salt mines in southern Louisiana. Limited numerical modeling also was performed to serve as a guide in selecting test layouts and for interpreting test data.

  12. Long-Term Stability of Teacher Certification Test Objective Job Analysis Ratings.

    ERIC Educational Resources Information Center

    Silvestro, John R.; And Others

    Public school ratings of the importance of subject-matter test objectives associated with teacher certification tests were examined by means of a job-analysis survey conducted in 1986 and a similar survey conducted in 1993. It was predicted that there would be a high degree of change in the importance ratings assigned to these test objectives…

  13. O2 evolution and cyclic electron flow around photosystem I in long-term ground batch culture of Euglena gracilis

    NASA Astrophysics Data System (ADS)

    An, Yanjun; Wang, Suqin; Hao, Zongjie; Zhou, Yiyong; Liu, Yongding

    2014-12-01

    Based on the purpose of better exploring the function of green producers in the closed aquatic biological life support system, the condition of dynamic O2 evolution and performance of cyclic electron flow around photosystem I (CEF-PSI) in long-term ground batch culture of Euglena gracilis were studied, the relationship between linear electron flow (LEF) and CEF-PSI was revealed, the function of CEF-PSI was investigated. Excellent consistency in O2 evolution pattern was observed in cultures grown in both closed and open containers, O2 evolution was strictly suppressed in phase 1, but the rate of it increased significantly in phase 2. CEF-PSI was proposed to be active during the whole course of cultivation, even in the declining phase 3, it still operated at the extent of 47-55%. It is suggested that the relationship between LEF and CEF-PSI is not only competition but also reciprocity. CEF-PSI was proposed to contribute to the considerable growth in phase 1; it was also suggested to play an important protective role against photosystem II (PSII) photoinhibition at the greatly enhanced level (approximately 80-95%) on the 2nd day. Our results in this research suggest that E. gracilis had very particular photosynthetic characteristics, the strict O2 evolution suppression in the initial culture phase might be a special light acclimation behavior, and CEF-PSI could be an important mechanism involved in this kind of adaptation to the changeable light environment.

  14. A multi-organ chip co-culture of neurospheres and liver equivalents for long-term substance testing.

    PubMed

    Materne, Eva-Maria; Ramme, Anja Patricia; Terrasso, Ana Paula; Serra, Margarida; Alves, Paula Marques; Brito, Catarina; Sakharov, Dmitry A; Tonevitsky, Alexander G; Lauster, Roland; Marx, Uwe

    2015-07-10

    Current in vitro and animal tests for drug development are failing to emulate the systemic organ complexity of the human body and, therefore, often do not accurately predict drug toxicity, leading to high attrition rates in clinical studies (Paul et al., 2010). The phylogenetic distance between humans and laboratory animals is enormous, this affects the transferability of animal data on the efficacy of neuroprotective drugs. Therefore, many neuroprotective treatments that have shown promise in animals have not been successful when transferred to humans (Dragunow, 2008; Gibbons and Dragunow, 2010). We present a multi-organ chip capable of maintaining 3D tissues derived from various cell sources in a combined media circuit which bridges the gap in systemic and human tests. A steady state co-culture of human artificial liver microtissues and human neurospheres exposed to fluid flow over two weeks in the multi-organ chip has successfully proven its long-term performance. Daily lactate dehydrogenase activity measurements of the medium and immunofluorescence end-point staining proved the viability of the tissues and the maintenance of differentiated cellular phenotypes. Moreover, the lactate production and glucose consumption values of the tissues cultured indicated that a stable steady-state was achieved after 6 days of co-cultivation. The neurospheres remained differentiated neurons over the two-week cultivation in the multi-organ chip, proven by qPCR and immunofluorescence of the neuronal markers βIII-tubulin and microtubule-associated protein-2. Additionally, a two-week toxicity assay with a repeated substance exposure to the neurotoxic 2,5-hexanedione in two different concentrations induced high apoptosis within the neurospheres and liver microtissues, as shown by a strong increase of lactate dehydrogenase activity in the medium. The principal finding of the exposure of the co-culture to 2,5-hexanedione was that not only toxicity profiles of two different doses

  15. Voluntary Testing for HIV Antibodies among Clients in Long-Term Substance Treatment.

    ERIC Educational Resources Information Center

    Galea, Robert P.; And Others

    1988-01-01

    Describes voluntary testing for human immunodeficiency virus (HIV) in a residential substance abuse treatment program; highlights discussion group involving 5 clients who tested positive for HIV. Notes that clients in HIV groups dropped out of treatment at significantly lower percentages than clients in general, indicating HIV identification…

  16. Integrated Corrosion Facility for long-term testing of candidate materials for high-level radioactive waste containment

    SciTech Connect

    Estill, J.C.; Dalder, E.N.C.; Gdowski, G.E.; McCright, R.D.

    1994-10-01

    A long-term-testing facility, the Integrated Corrosion Facility (I.C.F.), is being developed to investigate the corrosion behavior of candidate construction materials for high-level-radioactive waste packages for the potential repository at Yucca Mountain, Nevada. Corrosion phenomena will be characterized in environments considered possible under various scenarios of water contact with the waste packages. The testing of the materials will be conducted both in the liquid and high humidity vapor phases at 60 and 90{degrees}C. Three classes of materials with different degrees of corrosion resistance will be investigated in order to encompass the various design configurations of waste packages. The facility is expected to be in operation for a minimum of five years, and operation could be extended to longer times if warranted. A sufficient number of specimens will be emplaced in the test environments so that some can be removed and characterized periodically. The corrosion phenomena to be characterized are general, localized, galvanic, and stress corrosion cracking. The long-term data obtained from this study will be used in corrosion mechanism modeling, performance assessment, and waste package design. Three classes of materials are under consideration. The corrosion resistant materials are high-nickel alloys and titanium alloys; the corrosion allowance materials are low-alloy and carbon steels; and the intermediate corrosion resistant materials are copper-nickel alloys.

  17. Is nonword repetition a test of phonological memory or long-term knowledge? It all depends on the nonwords.

    PubMed

    Gathercole, S E

    1995-01-01

    The extent to which children's performance on tests of nonword repetition is constrained by phonological working memory and long-term lexical knowledge was investigated in a longitudinal study of 70 children tested at 4 and 5 years of age. At each time of testing, measures of nonword repetition, memory span, and vocabulary knowledge were obtained. Reading ability was also assessed at 5 years. At both ages, repetition accuracy was greater for nonwords of high- rather than low-rated wordlikeness, and memory-span measures were more closely related to repetition accuracy for the low-wordlike than for the high-wordlike stimuli. It is argued that these findings indicate that nonword repetition for unwordlike stimuli is largely dependent on phonological memory, whereas repetition for wordlike items is also mediated by long-term lexical knowledge and is therefore less sensitive to phonological memory constraints. Reading achievement was selectively linked with earlier repetition scores for low-wordlike nonwords, suggesting a phonological memory contribution in the early stages of reading development. Vocabulary knowledge was associated with repetition accuracy for both low- and high-wordlike nonwords, consistent with the notion that lexical knowledge and nonword repetition share a reciprocal developmental relationship. PMID:7885268

  18. Non-destructive testing on aramid fibres for the long-term assessment of interventions on heritage structures

    NASA Astrophysics Data System (ADS)

    Ceravolo, R.; De Marchi, A.; Pinotti, E.; Surace, C.; Zanotti Fragonara, L.

    2015-07-01

    High strength fibre reinforced polymers (FRPs) are composite materials made of fibres such as carbon, aramid and/or glass, and a resin matrix. FRPs are commonly used for structural repair and strengthening interventions and exhibit high potential for applications to existing constructions, including heritage buildings. In regard to aramid fibres, uncertainties about the long-term behaviour of these materials have often made the designers reluctant to use them in structural engineering. The present study describes simple and non-destructive nonlinearity tests for assessing damage or degradation of structural properties in Kevlar fibres. This was obtained by using high precision measurements to detect small deviations in the dynamic response measured on fibres and ropes. The change in dynamic properties was then related to a damage produced by exposure of the sample to UV rays for a defined time period, which simulated long-term sun exposure. In order to investigate the sensitivity of such an approach to damage detection, non-linearity characterisation tests were conducted on aramid fibres in both damaged and undamaged states. With the purpose of carrying out dynamic tests on small fibre specimens, a dedicated instrumentation was designed and built in cooperation with the Metrology Laboratory of the Department of Electronics at the Politecnico di Torino.

  19. Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine.

    PubMed

    De Wijs-Meijler, Daphne P M; Stam, Kelly; van Duin, Richard W B; Verzijl, Annemarie; Reiss, Irwin K; Duncker, Dirk J; Merkus, Daphne

    2016-01-01

    This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise. Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling. After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage. The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals

  20. Low-flow, long-term air sampling under normal domestic activity to measure house dust mite and cockroach allergens.

    PubMed

    Park, Jung Won; Kim, Cheol Woo; Kang, Dae Bong; Lee, In Young; Choi, Soo Young; Yong, Tai-Soon; Shin, Dong Cheon; Kim, Kyu Earn; Hong, Chein-Soo

    2002-01-01

    Successful applications of air sampling for the quantification of exposure to indoor allergens have been reported, but its efficiency is still controversial. We evaluated whether the low-flow, long-term air sampling in normal domestic activity conditions can quantify the exposure of house dust mites (HDM) and cockroaches (CR) allergens or not. Airborne Der f 1 and Bla g 1 were captured with a personal air sampler in 25 bedrooms during normal domestic activity. Quantification of the major allergens in the reservoir dust and the extraction of the air sampler filters were done with two-site ELISA kits. Airborne Der f 1 was measured above the threshold level of detection in 15 houses (60%). Detection rate of airborne Der f 1 was significantly higher in those houses where D. farinae was microscopically found in the reservoir dusts (76.5% vs. 25%, chi 2 = 6.0, p = 0.014). Airborne Der f 1 was more frequently detected in the houses with higher Der f 1 (> or = 10 micrograms/g dust) in bedding reservoir dust than the other group (91% vs. 35.7%, chi 2 = 7.819, p = 0.005), and the median value of airborne Der f 1 was also significantly higher in that group (14.0 pg/m3 vs. below detection limit, p = 0.002). Airborne Der f 1 was significantly correlated with Der f 1 in bedding reservoir dust (r = 0.591, p < 0.01). Airborne Bla g 1 was measured with ELISA in 16 houses (64%), and it was more frequently detected in the houses where the CRs were captured by adhesive traps (91% vs. 57%, chi 2 = 3,484, p = 0.06). The median concentration of Bla g 1 in the filter was also higher in the houses with captured CRs (0.12 vs. 0.05 mU/m3, p = 0.06), but the level of Bla g 1 did not correlate with that of the bedding dusts or the floor dusts of kitchen. These results suggested that airborne HDM or CR allergens could be measured by low-flow, long-term air sampling, and that it might be one of appropriate modalities for evaluating personal exposure to HDM and CR allergens. PMID:12926189

  1. Early work load tests for evaluation of long-term prognosis of acute myocardial infarction.

    PubMed Central

    Granath, A; Södermark, T; Winge, T; Volpe, U; Zetterquist, S

    1977-01-01

    Exercise tests performed 3 and 9 weeks after acute myocardial infarction in 205 patients were found to give prognostic information on the survival during a follow-up period of 2 to 5 years. The appearance of tachycardia, major ventricular arrhythmias, or anginal complaints during these early exercise tests was thus accompanied by a significantly increased mortality during the observation period. Ventricular arrhythmias disclosed by exercise proved to be of higher prognostic significance than those recorded at rest on the same occasions. The usefulness of early exercise tests in the evaluation of the response to antiarrhythmic treatment after acute myocardial infarction as well as of the prognostic importance of the effects was documented in a smaller series of patients. PMID:884025

  2. Changing the Philosophy of Care in Long-Term Care: Testing of the Restorative Care Intervention

    ERIC Educational Resources Information Center

    Resnick, Barbara; Gruber-Baldini, Ann L.; Galik, Elizabeth; Pretzer-Aboff, Ingrid; Russ, Karin; Hebel, J. Richard; Zimmerman, Sheryl

    2009-01-01

    Purpose: The purpose of this study was to test the effectiveness of a 12-month restorative care (Res-Care) intervention on the beliefs related to Res-Care, knowledge of Res-Care, observed performance of Res-Care with residents, and job satisfaction among nursing assistants (NAs) in nursing home (NH) settings. Design and Methods: This was a…

  3. Test-Enhanced Learning in the Classroom: Long-Term Improvements from Quizzing

    ERIC Educational Resources Information Center

    Roediger, Henry L., III; Agarwal, Pooja K.; McDaniel, Mark A.; McDermott, Kathleen B.

    2011-01-01

    Three experiments examined whether quizzing promotes learning and retention of material from a social studies course with sixth grade students from a suburban middle school. The material used in the experiments was the course material students were to learn and some of the dependent measures were the actual tests on which students received grades.…

  4. Long term storage test of titanium material with liquid fluorine propellant

    NASA Technical Reports Server (NTRS)

    Denson, J. R.; English, W. D.; Roth, J.; Toy, A.

    1979-01-01

    The compatibility of 6AL-4V Ti with propellant grade GF2 and LF2 at 77 K for up to 3 years was investigated. Titanium double coupons, annealed or heat treated, with 16 or 64 RMS finishes, were immersed in F2 in individual Pyrex capsules and stored under LN2 for 29 and 39 months. Pre and post immersion tests were performed on the propellant and coupons. Chemical analysis of the propellant did not reveal any significant changes due to titanium corrosion. Gravimetric, visual, microscopic, and metallurgical examination with pitting analysis did not reveal gross corrosion of the titanium although pitting appears to be greater after 39 months exposure. The increase in pit size and number raises the possibility of unpredictable crack propagation instability. Fracture toughness tests are necessary to define this possibility.

  5. Long-term leaching test of organo-contaminated cement-clay pastes.

    PubMed

    Zampori, L; Stampino, P Gallo; Dotelli, G

    2009-10-30

    The aim of the present work is to investigate the effect of a prolonged leaching test (more than a year) on the microstructure of solidified cementitious wasteforms. A set of four different cement-based monoliths (Ap, Bp, Cp and Dp) was prepared, and for each series an uncontaminated sample was prepared as reference (A-D). An organoclay was added in all pastes as pre-sorbent material for the pollutant; a model liquid organic pollutant, 2-chloroaniline (2-CA), was added only in the contaminated ones and different types of admixtures, chosen among those typically employed in the concrete mix-design, were used. After the first 28 days of curing, all the monoliths, contaminated and uncontaminated, underwent a dynamic leach testing (DLT) for more than 1 year in deionized water. PMID:19524362

  6. Assessing photovoltaic module degradation and lifetime from long term environmental tests

    NASA Technical Reports Server (NTRS)

    Otth, D. H.; Ross, R. G., Jr.

    1983-01-01

    The photovoltaic module failure mechanisms related to temperature, humidity, and electrical bias are analyzed using the data collected over a period of 20 years from various sites in the U.S. The approach is based on measuring the rate dependence of the mechanisms on site stress levels, and then using the rate data to analytically estimate the field life by means of computer models of the site environment. A correlation is established between the accelerated constant-stress testing and the time-varying field exposures. Test results are presented for two failure mechanisms for a module design featuring polyvinyl butyral encapsulant for the temperature range of 85 to 100 C and 85-percent relative humidity.

  7. Long-term static testing of an FRP prototype highway structure

    NASA Astrophysics Data System (ADS)

    Lee, J.; Hollaway, L.; Thorne, A.; Head, P.

    In recent years it has become apparent that the labour and maintenance costs of highway structures fabricated from conventional constructional materials (i.e. steel and concrete) are rising, and therefore the whole life cost of these structures is being significantly affected. Highway structures manufactured from advanced composite materials provide a viable solution to reduce substantially both the labour and the maintenance costs, whilst providing structures that behave in accordance with the present British code of practice for highway structures. The principle objectives of the investigations were to undertake experimentally and to verify, where applicable, numerically the suitability of advanced fibre-reinforced polymer (FRP) composite materials manufactured in the form of box beams for use as highway structures. It was also important to research into any unique behaviour exhibited by the FRP structures while under test and to develop relevant theoretical models and formulae to characterize completely this behaviour. The composite box beam showed no signs of global deterioration and generally behaved as predicted; the short term stiffness of the beam measured at specific times during the test did not decrease to any extent. There was some local flexural cracking in the connectors at the position of the applied loads, but this can be eliminated by design. The creep and deflections of the beam at the end of the test were well within acceptable limits.

  8. Liquid Hydrogen Zero-Boiloff Testing and Analysis for Long-Term Orbital Storage

    NASA Astrophysics Data System (ADS)

    Hastings, L. J.; Hedayat, A.; Bryant, C. B.; Flachbart, R. H.

    2004-06-01

    Advancement of cryocooler and passive insulation technologies in recent years has improved the prospects for zero-boiloff (ZBO) storage of cryogenic fluids. The ZBO concept involves the use of a cryocooler/radiator system to balance storage system incoming and extracted energy such that zero boiloff (no venting) occurs. A large-scale demonstration of the ZBO concept was conducted using the Marshall Space Flight Center (MSFC) multipurpose hydrogen test bed (MHTB) along with a commercial cryocooler unit. The liquid hydrogen (LH2) was withdrawn from the tank, passed through the cryocooler heat exchanger, and then the chilled liquid was sprayed back into the tank through a spray bar. The spray bar recirculation system was designed to provide destratification independent of ullage and liquid positions in a zero-gravity environment. The insulated MHTB tank, combined with the vacuum chamber conditions, enabled orbital storage simulation. ZBO was demonstrated for fill levels of 95%, 50%, and 25%. At each fill level, a steady-state boiloff test was performed prior to operating the cryocooler to establish the baseline heat leak. Control system logic based on real-time thermal data and ullage pressure response was implemented to automatically provide a constant tank pressure. A comparison of test data and analytical results is presented in this paper.

  9. Long-term lethal toxicity test with the crustacean Artemia franciscana.

    PubMed

    Manfra, Loredana; Savorelli, Federica; Pisapia, Marco; Magaletti, Erika; Cicero, Anna Maria

    2012-01-01

    Our research activities target the use of biological methods for the evaluation of environmental quality, with particular reference to saltwater/brackish water and sediment. The choice of biological indicators must be based on reliable scientific knowledge and, possibly, on the availability of standardized procedures. In this article, we present a standardized protocol that used the marine crustacean Artemia to evaluate the toxicity of chemicals and/or of marine environmental matrices. Scientists propose that the brine shrimp (Artemia) is a suitable candidate for the development of a standard bioassay for worldwide utilization. A number of papers have been published on the toxic effects of various chemicals and toxicants on brine shrimp (Artemia). The major advantage of this crustacean for toxicity studies is the overall availability of the dry cysts; these can be immediately used in testing and difficult cultivation is not demanded. . Cyst-based toxicity assays are cheap, continuously available, simple and reliable and are thus an important answer to routine needs of toxicity screening, for industrial monitoring requirements or for regulatory purposes. The proposed method involves the mortality as an endpoint. The numbers of survivors were counted and percentage of deaths were calculated. Larvae were considered dead if they did not exhibit any internal or external movement during several seconds of observation. This procedure was standardized testing a reference substance (Sodium Dodecyl Sulfate); some results are reported in this work. This article accompanies a video that describes the performance of procedural toxicity testing, showing all the steps related to the protocol. PMID:22525984

  10. Long term testing of start-stop cycles on high temperature PEM fuel cell stack

    NASA Astrophysics Data System (ADS)

    Kannan, Arvind; Kabza, Alexander; Scholta, Joachim

    2015-03-01

    A PEM fuel cell with an operating temperature above 100 °C is desired for increasing the kinetics of reactions, reduced sensitivity to impurities of the fuel, as well as for the reduction of the requirements on thermal and water management systems. High Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFC) can effectively be combined with CHP systems to offer a simple system design and higher overall system efficiencies. For HT-PEMFC systems, the development of elaborated start/stop strategies is essential in mitigation of fuel cell degradation during these events. A 5 cell co-flow stack is assembled with BASF P1100W membrane electrode assembly (MEA) with an active area of 163.5 cm2. Continuous operation and more than 1500 start stop cycles have been performed in order to study the degradation effects of both continuous operation and of repeated start stops using a protective start-stop algorithm, which is designed to avoid the formation of aggressive cell potentials. The repeated use of this procedure led to a degradation of 26 μV/cycle at a current density of 0.25 A cm-2 and 11 μV/cycle at a current density of 0.03 A cm-2. At open circuit voltage (OCV), a higher degradation rate of 133 μV/cycle was observed.

  11. A field assessment of long-term laboratory sediment toxicity tests with the amphipod Hyalella azteca

    USGS Publications Warehouse

    Ingersoll, C.G.; Wang, N.; Hayward, J.M.R.; Jones, J.R.; Jones, S.B.; Ireland, D.S.

    2005-01-01

    Response of the amphipod Hyalella azteca exposed to contaminated sediments for 10 to 42 d in laboratory toxicity tests was compared to responses observed in controlled three-month invertebrate colonization exposures conducted in a pond. Sediments evaluated included a sediment spiked with dichlorodiphenyldichloroethane (DDD) or dilutions of a field sediment collected from the Grand Calumet River (GCR) in Indiana (USA) (contaminated with organic compounds and metals). Consistent effects were observed at the highest exposure concentrations (400 ??g DDD/goc [DDD concentrations normalized to grams of organic carbon (goc) in sedimentl or 4% GCR sediment) on survival, length, and reproduction of amphipods in the laboratory and on abundance of invertebrates colonizing sediments in the field. Effect concentrations for DDD observed for 10-d length and 42-d reproduction of amphipods (e.g., chronic value [ChV] of 66 ??g DDD/goc and 25% inhibition concentration [IC25] of 68 ??g DDD/goc for reproduction) were similar to the lowest effect concentrations for DDD measured on invertebrates colonizing sediment the field. Effect concentrations for GCR sediment on 28-d survival and length and 42-d reproduction and length of amphipods (i.e., ChVs of 0.20-0.66% GCR sediment) provided more conservative effect concentrations compared to 10-d survival or length of amphipods in the laboratory or the response of invertebrates colonizing sediment in the field (e.g., ChVs of 2.2% GCR sediment). Results of this study indicate that use of chronic laboratory toxicity tests with H. azteca and benthic colonization studies should be used to provide conservative estimates of impacts on benthic communities exposed to contaminated sediments. Bioaccumulation of DDD by oligochaetes colonizing the DDD-spiked sediment was similar to results of laboratory sediment tests previously conducted with the oligochaete Lumbriculus variegates, confirming that laboratory exposures can be used to estimate

  12. Long-term Lethal Toxicity Test with the Crustacean Artemia franciscana

    PubMed Central

    Manfra, Loredana; Savorelli, Federica; Pisapia, Marco; Magaletti, Erika; Cicero, Anna Maria

    2012-01-01

    Our research activities target the use of biological methods for the evaluation of environmental quality, with particular reference to saltwater/brackish water and sediment. The choice of biological indicators must be based on reliable scientific knowledge and, possibly, on the availability of standardized procedures. In this article, we present a standardized protocol that used the marine crustacean Artemia to evaluate the toxicity of chemicals and/or of marine environmental matrices. Scientists propose that the brine shrimp (Artemia) is a suitable candidate for the development of a standard bioassay for worldwide utilization. A number of papers have been published on the toxic effects of various chemicals and toxicants on brine shrimp (Artemia). The major advantage of this crustacean for toxicity studies is the overall availability of the dry cysts; these can be immediately used in testing and difficult cultivation is not demanded1,2. Cyst-based toxicity assays are cheap, continuously available, simple and reliable and are thus an important answer to routine needs of toxicity screening, for industrial monitoring requirements or for regulatory purposes3. The proposed method involves the mortality as an endpoint. The numbers of survivors were counted and percentage of deaths were calculated. Larvae were considered dead if they did not exhibit any internal or external movement during several seconds of observation4. This procedure was standardized testing a reference substance (Sodium Dodecyl Sulfate); some results are reported in this work. This article accompanies a video that describes the performance of procedural toxicity testing, showing all the steps related to the protocol. PMID:22525984

  13. Long-Term Care

    MedlinePlus

    ... this page please turn Javascript on. Long-Term Care What Is Long-Term Care? Long-term care involves a variety of services ... the Escape (Esc) button on your keyboard.) Most Care Provided at Home Long-term care is provided ...

  14. Long-term testing and evaluation of cathode components in a commercial aluminum cell

    SciTech Connect

    Church, K.D.; Morris, E.G.; Joo', L.A. ); Stewart, D.V.; Morgan, W.R.; Tabereaux, A. )

    1990-04-01

    The purpose of modeling thermal stresses in TiB{sub 2}-G cathode elements was to aide in the design of the final TiB{sub 2}-G cathode element shape to be used in an industrial reduction cell based on knowledge of thermal stress values and an estimate of the probability of element failure. Five finite element models of four TiB{sub 2}-G cathode element shapes were constructed (Figures 1-5) to model thermal stresses resulting from step changes in temperature of 25{degree}C--960{degree}C and 300{degree}C--960{degree}C. The models were developed to represent worst case'' conditions, that is, conditions representing the greatest anticipated values of thermal stress likely to be encountered. ANSYS was used to perform the thermal stress modeling. ANSYS is a general purpose finite element code available from Swanson Analysis Systems, Incorporated. Modeling thermal stress in ANSYS for a step change in temperature requires an initial transient thermal analysis followed by a structural analysis. After the geometry of each model was defined, material properties were specified, and heat transfer boundary conditions developed. The finite element models were constructed using convective heat transfer boundary conditions as a means of specifying heat flow into the models. Convection faces and convective heat transfer coefficients were defined at the TiB{sub 2}-G -- molten metal interfaces. A uniform starting temperature of either 25{degree}C or 300{degree}C was assigned and the models were solved for transient temperature distribution and thermally induced stress. LCHEM codes were utilized to model voltage distribution and current density in reduction cells utilizing TiB{sub 2}-G cathode elements. 4 refs., 119 figs., 9 tabs.

  15. Long-term outcomes of fractional flow reserve-guided vs. angiography-guided percutaneous coronary intervention in contemporary practice

    PubMed Central

    Li, Jing; Elrashidi, Muhamad Y.; Flammer, Andreas J.; Lennon, Ryan J.; Bell, Malcolm R.; Holmes, David R.; Bresnahan, John F.; Rihal, Charanjit S.; Lerman, Lilach O.; Lerman, Amir

    2013-01-01

    Aims Fractional flow reserve (FFR) is the reference standard for the assessment of the functional significance of coronary artery stenoses, but is underutilized in daily clinical practice. We aimed to study long-term outcomes of FFR-guided percutaneous coronary intervention (PCI) in the general clinical practice. Methods and results In this retrospective study, consecutive patients (n = 7358), referred for PCI at the Mayo Clinic between October 2002 and December 2009, were divided in two groups: those undergoing PCI without (PCI-only, n = 6268) or with FFR measurements (FFR-guided, n = 1090). The latter group was further classified as the FFR-Perform group (n = 369) if followed by PCI, and the FFR-Defer group (n = 721) if PCI was deferred. Clinical events were compared during a median follow-up of 50.9 months. The Kaplan–Meier fraction of major adverse cardiac events at 7 years was 57.0% in the PCI-only vs. 50.0% in the FFR-guided group (P = 0.016). Patients with FFR-guided interventions had a non-significantly lower rate of death or myocardial infarction compared with those with angiography-guided interventions [hazard ratio (HR): 0.85, 95% CI: 0.71–1.01, P = 0.06]; the FFR-guided deferred-PCI strategy was independently associated with reduced rate of myocardial infarction (HR: 0.46, 95% CI: 0.26–0.82, P = 0.008). After excluding patients with FFR of 0.75–0.80 and deferring PCI, the use of FFR was significantly associated with reduced rate of death or myocardial infarction (HR: 0.80, 95% CI: 0.66–0.96, P = 0.02). Conclusion In the contemporary practice, an FFR-guided treatment strategy is associated with a favourable long-term outcome. The current study supports the use of the FFR for decision-making in patients undergoing cardiac catheterization. PMID:23344979

  16. A new test for long-term spatial memory using an operant chamber in mice.

    PubMed

    Delcasso, Sebastien; Jeantet, Yannick; Cho, Yoon H

    2007-03-28

    As part of ongoing efforts to develop fully automated and standardized behavioral tasks to probe cognitive and mnemonic capabilities of mice, we have constructed a new rectangular operant chamber. The chamber contains numerous nose poke holes, distributed over three of its inner walls that are identifiable by their spatial locations. Using this apparatus, we have developed a 'spatial' memory task using a successive reversal discrimination paradigm. Mice learn to discriminate, by trial and error, the position of a single valid hole during a Presentation session wherein they obtained a maximum of 20 reinforcements or 15 min time elapsed. Following a delay interval, they were resubmitted to the same task (Test) using the same reinforced hole. Results indicated that C57BL/6 mice exhibited a significant improvement during the Test, the magnitude of the improvement (memory savings) being dependent on the length of retention intervals ranging from 5 min to 24h. In addition, discrimination performance was sensitive to scopolamine in a dose dependent manner. The simplicity in task set up and the minimal labor and space requirements make this task suitable for high throughput behavioral characterization of genetically modified mice. PMID:17223205

  17. An Update of the Nation's Long-Term Strategic Needs for NASA's Aeronautics Test Facilities

    NASA Technical Reports Server (NTRS)

    Anton, Philip S.; Raman, Raj; Osburg, Jan; Kallimani, James G.

    2009-01-01

    The National Aeronautics and Space Administration's (NASA's) major wind tunnel (WT), propulsion test (PT), and simulation facilities exist to serve NASA's and the nation's aeronautics needs. RAND Corporation researchers conducted a prior study of these facilities from 2002 to 2003, identifying (1) NASA's continuing ability to serve national needs, (2) which facilities appear strategically important from an engineering perspective given the vehicle classes the nation investigates and produces, and (3) management challenges and issues. This documented briefing (DB) is the final report from a new, one-year study (conducted from September 2006 through January 2008), partially updating the prior assessment. The study focuses on updating the list of facilities in the prior study that were deemed to be strategically important (again, from an engineering perspective) in serving those needs. This update also adds a new assessment of national needs for six major aeronautics simulators at NASA and lists those deemed strategically important.

  18. Neuropsychological Testing in Interventional Cardiology Staff after Long-Term Exposure to Ionizing Radiation.

    PubMed

    Marazziti, Donatella; Tomaiuolo, Francesco; Dell'Osso, Liliana; Demi, Virginia; Campana, Serena; Piccaluga, Emanuela; Guagliumi, Giulio; Conversano, Ciro; Baroni, Stefano; Andreassi, Maria Grazia; Picano, Eugenio

    2015-10-01

    This study aimed at comparing neuropsychological test scores in 83 cardiologists and nurses (exposed group, EG) working in the cardiac catheterization laboratory, and 83 control participants (non exposed group, nEG), to explore possible cognitive impairments. The neuropsychological assessment was carried out by means of a battery called "Esame Neuropsicologico Breve." EG participants showed significantly lower scores on the delayed recall, visual short-term memory, and semantic lexical access ability than the nEG ones. No dose response could be detected. EG participants showed lower memory and verbal fluency performances, as compared with nEG. These reduced skills suggest alterations of some left hemisphere structures that are more exposed to IR in interventional cardiology staff. On the basis of these findings, therefore, head protection would be a mandatory good practice to reduce effects of head exposure to ionizing radiation among invasive cardiology personnel (and among other exposed professionals). PMID:26400563

  19. Estimation of Recent and Long-Term Malaria Transmission in a Population by Antibody Testing to Multiple Plasmodium falciparum Antigens

    PubMed Central

    Ondigo, Bartholomew N.; Hodges, James S.; Ireland, Kathleen F.; Magak, Ng'wena G.; Lanar, David E.; Dutta, Sheetij; Narum, David L.; Park, Gregory S.; Ofulla, Ayub V.; John, Chandy C.

    2014-01-01

    Background. Tools that estimate recent and long-term malaria transmission in a population would be highly useful for malaria elimination programs. Methods. The prevalence of antibodies to 11 Plasmodium falciparum antigens was assessed by cytometric bead assay or enzyme-linked immunosorbent assay in 1000 people in a highland area of Kenya over 14 months, during a period of interrupted malaria transmission. Results. Antibodies differed by antigen in acquisition with age: rapid (>80% antibody positive by age 20 years, 5 antigens), moderate (>40% positive by age 20 years, 3 antigens), or slow (<40% positive by age 20 years, 3 antigens). Antibody seroreversion rates in the 14 months between samples decreased with age rapidly (7 antigens), slowly (3 antigens), or remained high at all ages (schizont extract). Estimated antibody half-lives in individuals >10 years of age were long (40 to >80 years) for 5 antigens, moderate (5–20 years) for 3 antigens, and short (<1 year) for 3 antigens. Conclusions. Antibodies to P. falciparum antigens in malaria-endemic areas vary by age, antigen, and time since last exposure to P. falciparum. Multiplex P. falciparum antibody testing could provide estimates of long-term and recent malaria transmission and potentially of a population's susceptibility to future clinical malaria. PMID:24737801

  20. Long term cultures of primary human hepatocytes as an alternative to drug testing in animals.

    PubMed

    Ullrich, Anett; Stolz, Donna B; Ellis, Ewa C; Strom, Stephen C; Michalopoulos, George K; Hengstler, Jan G; Runge, Dieter

    2009-01-01

    Due to species differences, primary human hepatocytes are still the in vitro system of choice to analyse liver specific processes and functions. Human hepatocytes were cultured for several weeks in a serum-free two-dimensional culture system, which was used to study the effects of acetaminophen (APAP) on hepatocellular functions and vitality. Non-invasive determinations of albumin, urea and lactate dehydrogenase concentrations in cell culture supernatants allowed continuous monitoring for at least two weeks. APAP was applied every 4 days for 24 h. Each application reduced urea production by 25% and albumin synthesis by approximately 70% without any effects on cellular viability. After removal of the substance, hepatocellular functions returned to control levels within one (urea) to three (albumin) days. The repetitive analyses of APAP-mediated effects on cellular metabolism led to identical results for up to five cycles. The drug also caused reversible and repetitive ultrastructural modifications, in particular an almost complete replacement of rough endoplasmic reticulum by smooth endoplasmic reticulum and a massive degradation of glycogen stores. The data demonstrate the suitability of the culture system to serve as a model for repetitive testing of drug-mediated changes on hepatocellular functions, thereby reducing animal studies during drug development. PMID:20383475

  1. The efficacy of hepatitis B vaccination program in upper Egypt: Flow cytometry and the evaluation of long term immunogenicity.

    PubMed

    Makhlouf, Nahed A; Farghaly, Ahlam M; Zaky, Saad; Rashed, Hebat-Alla G; Abu Faddan, Nagla H; Sayed, Douaa; El-Badawy, Omnia; Afifi, Noha; Hamza, Wafaa S; El-Sayed, Yousseria

    2016-09-01

    Anti-HBs levels wanes with time. Many studies discussed the B cell response to HBV vaccine. However, the data about memory T cell response are limited. To evaluate the efficacy of hepatitis B vaccine via evaluating anti-HBs levels and HBsAg specific memory T-lymphocytes through descriptive study. The study was conducted in a tertiary care setting. This study included 440 vaccinated persons during infancy. Group I: 6 to less than 10 years old; Group II: 10 to less than 14 years old; Group III: 14 to less than 17 years old; Group IV: 17 years old. The serum samples were screened for HBV markers. Cytokines secretion by HBsAg-specific memory CD45RO(+) CD4(+) T cells was measured after in vitro culture using flow cytometry. The mean titer of anti-HBs was higher in group I in comparison to others (P-value = 0.000 for each). IFN-γ and IL-4 secreted by memory CD4(+) T cells were positive in all with anti-HBs >100 mIU/ml, while positive in 87% and 75% of participants with anti-HBs <10 mIU/ml and positive in 73% and 32% of participants with absent anti-HBs. The percentage of cells secreting IFN-γ and those secreting IL-4 were higher among participants with serum anti-HBs >100 mIU/ml than those having <10 mIU/ml or absent (P < 0.001 for each). Anti-HBs positivity decreased with time since childhood vaccination. Breakthrough infections are rare in vaccinated persons. Hepatitis-B vaccine is efficient in controlling HBV infection. Flow cytometry is a useful tool to assess the long term persistence of T cell memory after childhood vaccination. J. Med. Virol. 88:1567-1575, 2016. © 2016 Wiley Periodicals, Inc. PMID:26910304

  2. Renal epithelia in long term gradient culture for biomaterial testing and tissue engineering.

    PubMed

    Minuth, Will W; Schumacher, Karl; Strehl, Raimund

    2005-01-01

    In the organism epithelia perform perfect barrier functions. Strong rheological and mechanical influences constitute the normal environment of this tissue throughout life. Most epithelia are exposed to different fluids at the luminal and basal sides. To obtain realistic information about tissue development in modern biomaterial testing and tissue engineering it is necessary to mimick the natural environment of epithelia. Cultured cells are brought in contact with an artificial extracellular matrix to determine whether proper development into a functional epithelium occurs. As under natural conditions the cultures have to withstand mechanical and fluid stress over a prolonged period of time in close contact to a selected biomaterial. However, development of tissue-specific features such as polarization, tightness and transport under in vitro conditions will only occur, if the biomaterial and the culture conditions support tissue development. Leakage, edge damage and pressure differences during culture have to be avoided so that the natural functions of the growing epithelium can develop. Our aim is to generate functional epithelia derived from renal explants containing stem cells, which are microsurgically isolated and placed into specific O-ring carriers for optimal handling. The cells develop in combination with a collagenous matrix from an embryonic into a functional collecting duct (rCD) epithelium. To achieve optimal culture conditions the tissue is placed in a gradient culture container. A typical environment can be simulated by superfusing different culture media at the luminal and basal sides. Within days epithelia growing inside the gradient container build up a physiological barrier, which is maintained during the whole culture period. The described method allows to investigate the influence of new biomaterials over prolonged periods of time. PMID:15623930

  3. Long-Term Cycle-Life Testing Of Large-Scale Lithium-Ion Cells For Space Applications

    NASA Astrophysics Data System (ADS)

    Naito, Hitoshi; Kawase, Makoto; Takagi, Kohei; Yamada, Chisa; Kibe, Koichi

    2011-10-01

    The specific advantages of lithium-ion technology in energy density and working voltage offer the possibility of huge reductions in battery mass, and hence contribute to lower launch costs and enable missions that have critical weight and/or volume margins. Recently, To facilitate the applications of lithium-ion battery in a spacecraft, we began conducting the long-term evaluation on 10-100 Ah-class lithium-ion cells by simulating satellites' operation in 1998. Thus far, we have verified about 10- and 20-year LEO and GEO satellite operations by real-time continuous testing. These results indicate good applicability of lithium-ion cells as long time power storage devices in a satellite. In this paper, we will provide a review of the latest cycle-life test results of these large-capacity lithium-ion cells.

  4. Long-term resource variation and group size: A large-sample field test of the Resource Dispersion Hypothesis

    PubMed Central

    Johnson, Dominic DP; Baker, Samantha; Morecroft, Michael D; Macdonald, David W

    2001-01-01

    Background The Resource Dispersion Hypothesis (RDH) proposes a mechanism for the passive formation of social groups where resources are dispersed, even in the absence of any benefits of group living per se. Despite supportive modelling, it lacks empirical testing. The RDH predicts that, rather than Territory Size (TS) increasing monotonically with Group Size (GS) to account for increasing metabolic needs, TS is constrained by the dispersion of resource patches, whereas GS is independently limited by their richness. We conducted multiple-year tests of these predictions using data from the long-term study of badgers Meles meles in Wytham Woods, England. The study has long failed to identify direct benefits from group living and, consequently, alternative explanations for their large group sizes have been sought. Results TS was not consistently related to resource dispersion, nor was GS consistently related to resource richness. Results differed according to data groupings and whether territories were mapped using minimum convex polygons or traditional methods. Habitats differed significantly in resource availability, but there was also evidence that food resources may be spatially aggregated within habitat types as well as between them. Conclusions This is, we believe, the largest ever test of the RDH and builds on the long-term project that initiated part of the thinking behind the hypothesis. Support for predictions were mixed and depended on year and the method used to map territory borders. We suggest that within-habitat patchiness, as well as model assumptions, should be further investigated for improved tests of the RDH in the future. PMID:11511326

  5. Analysis of the immune system of multiple myeloma patients achieving long-term disease control by multidimensional flow cytometry

    PubMed Central

    Pessoa de Magalhães, Roberto J.; Vidriales, María-Belén; Paiva, Bruno; Fernandez-Gimenez, Carlos; García-Sanz, Ramón; Mateos, Maria-Victoria; Gutierrez, Norma C.; Lecrevisse, Quentin; Blanco, Juan F; Hernández, Jose; de las Heras, Natalia; Martinez-Lopez, Joaquin; Roig, Monica; Costa, Elaine Sobral; Ocio, Enrique M.; Perez-Andres, Martin; Maiolino, Angelo; Nucci, Marcio; De La Rubia, Javier; Lahuerta, Juan-Jose; San-Miguel, Jesús F.; Orfao, Alberto

    2013-01-01

    Multiple myeloma remains largely incurable. However, a few patients experience more than 10 years of relapse-free survival and can be considered as operationally cured. Interestingly, long-term disease control in multiple myeloma is not restricted to patients with a complete response, since some patients revert to having a profile of monoclonal gammopathy of undetermined significance. We compared the distribution of multiple compartments of lymphocytes and dendritic cells in the bone marrow and peripheral blood of multiple myeloma patients with long-term disease control (n=28), patients with newly diagnosed monoclonal gammopathy of undetermined significance (n=23), patients with symptomatic multiple myeloma (n=23), and age-matched healthy adults (n=10). Similarly to the patients with monoclonal gammopathy of undetermined significance and symptomatic multiple myeloma, patients with long-term disease control showed an expansion of cytotoxic CD8+ T cells and natural killer cells. However, the numbers of bone marrow T-regulatory cells were lower in patients with long-term disease control than in those with symptomatic multiple myeloma. It is noteworthy that B cells were depleted in patients with monoclonal gammopathy of undetermined significance and in those with symptomatic multiple myeloma, but recovered in both the bone marrow and peripheral blood of patients with long-term disease control, due to an increase in normal bone marrow B-cell precursors and plasma cells, as well as pre-germinal center peripheral blood B cells. The number of bone marrow dendritic cells and tissue macrophages differed significantly between patients with long-term disease control and those with symptomatic multiple myeloma, with a trend to cell count recovering in the former group of patients towards levels similar to those found in healthy adults. In summary, our results indicate that multiple myeloma patients with long-term disease control have a constellation of unique immune changes

  6. Analysis of the immune system of multiple myeloma patients achieving long-term disease control by multidimensional flow cytometry.

    PubMed

    Pessoa de Magalhães, Roberto J; Vidriales, María-Belén; Paiva, Bruno; Fernandez-Gimenez, Carlos; García-Sanz, Ramón; Mateos, Maria-Victoria; Gutierrez, Norma C; Lecrevisse, Quentin; Blanco, Juan F; Hernández, Jose; de las Heras, Natalia; Martinez-Lopez, Joaquin; Roig, Monica; Costa, Elaine Sobral; Ocio, Enrique M; Perez-Andres, Martin; Maiolino, Angelo; Nucci, Marcio; De La Rubia, Javier; Lahuerta, Juan-Jose; San-Miguel, Jesús F; Orfao, Alberto

    2013-01-01

    Multiple myeloma remains largely incurable. However, a few patients experience more than 10 years of relapse-free survival and can be considered as operationally cured. Interestingly, long-term disease control in multiple myeloma is not restricted to patients with a complete response, since some patients revert to having a profile of monoclonal gammopathy of undetermined significance. We compared the distribution of multiple compartments of lymphocytes and dendritic cells in the bone marrow and peripheral blood of multiple myeloma patients with long-term disease control (n=28), patients with newly diagnosed monoclonal gammopathy of undetermined significance (n=23), patients with symptomatic multiple myeloma (n=23), and age-matched healthy adults (n=10). Similarly to the patients with monoclonal gammopathy of undetermined significance and symptomatic multiple myeloma, patients with long-term disease control showed an expansion of cytotoxic CD8(+) T cells and natural killer cells. However, the numbers of bone marrow T-regulatory cells were lower in patients with long-term disease control than in those with symptomatic multiple myeloma. It is noteworthy that B cells were depleted in patients with monoclonal gammopathy of undetermined significance and in those with symptomatic multiple myeloma, but recovered in both the bone marrow and peripheral blood of patients with long-term disease control, due to an increase in normal bone marrow B-cell precursors and plasma cells, as well as pre-germinal center peripheral blood B cells. The number of bone marrow dendritic cells and tissue macrophages differed significantly between patients with long-term disease control and those with symptomatic multiple myeloma, with a trend to cell count recovering in the former group of patients towards levels similar to those found in healthy adults. In summary, our results indicate that multiple myeloma patients with long-term disease control have a constellation of unique immune changes

  7. Long-term Testing Results for the 2008 Installation of LED Luminaires at the I-35 West Bridge in Minneapolis

    SciTech Connect

    Kinzey, Bruce R.; Davis, Robert G.

    2014-09-30

    This document reports the long-term testing results from an extended GATEWAY project that was first reported in “Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting at the I-35W Bridge, in Minneapolis, MN,” August 2009. That original report presented the results of lighting the newly reconstructed I 35W Bridge using LEDs in place of conventional high-pressure sodium (HPS) roadway luminaires, comparing energy use and illuminance levels with a simulated baseline condition. That installation was an early stage implementation of LED lighting and remains one of the oldest installations in continued operation today. This document provides an update of the LED system’s performance since its installation in September 2008.

  8. Short and long term outcomes of 200 patients supported by continuous-flow left ventricular assist devices

    PubMed Central

    Tsiouris, Athanasios; Paone, Gaetano; Nemeh, Hassan W; Borgi, Jamil; Williams, Celeste T; Lanfear, David E; Morgan, Jeffrey A

    2015-01-01

    AIM: To study the institutional experience over 8 years with 200 continuous-flow (CF) - left ventricular assist devices (LVAD). METHODS: We evaluated our institution’s LVAD database and analyzed all patients who received a CF LVAD as a bridge to transplant (BTT) or destination therapy from March 2006 until June 2014. We identified 200 patients, of which 179 were implanted with a HeartMate II device (Thoratec Corp., Pleasanton, CA) and 21 received a Heartware HVAD (HeartWare Inc., Framingham, MA). RESULTS: The mean age of our LVAD recipients was 59.3 years (range 17-81), 76% (152/200) were males, and 49% were implanted for the indication of BTT. The survival rate for our LVAD patients at 30 d, 6 mo, 12 mo, 2 years, 3 years, and 4 years was 94%, 86%, 78%, 71%, 62% and 45% respectively. The mean duration of LVAD support was 581 d (range 2-2595 d). Gastrointestinal bleeding (was the most common adverse event (43/200, 21%), followed by right ventricular failure (38/200, 19%), stroke (31/200, 15%), re exploration for bleeding (31/200, 15%), ventilator dependent respiratory failure (19/200, 9%) and pneumonia (15/200, 7%). Our driveline infection rate was 7%. Pump thrombosis occurred in 6% of patients. Device exchanged was needed in 6% of patients. On multivariate analysis, preoperative liver dysfunction, ventilator dependent respiratory failure, tracheostomy and right ventricular failure requiring right ventricular assist device support were significant predictors of post LVAD survival. CONCLUSION: Short and long term survival for patients on LVAD support are excellent, although outcomes still remain inferior compared to heart transplantation. The incidence of driveline infections, pump thrombosis and pump exchange have declined significantly in recent years. PMID:26635927

  9. Long-term occlusion results with SILK flow diversion in 28 aneurysms: Do recanalizations occur during follow-up?

    PubMed Central

    Skalej, Martin; Beuing, Oliver; Eckert, Bernd; Behme, Daniel; Weber, Werner

    2015-01-01

    Background and purpose The purpose of this article is to report on the long-term success rates of Silk flow-diverter (FD) treatment in a multicenter prospective study for the treatment of complex aneurysms. Methods Between May 2008 and January 2011, all consecutive patients featuring complex intracranial aneurysms eligible for FD treatment with the Silk in three neurovascular centers were included. Clinical and imaging data were assessed during hospitalization and follow-up. Results Five patients were initially asymptomatic, 20 patients showed various neurological symptoms. Twenty-eight FDs were implanted in 25 patients treating 28 aneurysms. The immediate procedure-related morbidity was 8% (two of 25), mortality 0%. One procedure-related death was observed during follow-up (in-stent thrombosis). Compared to the immediate result nearly two of three aneurysms improved during follow-up; all angiographically confirmed inflow changes took place within six months after treatment. Final anatomic outcome in 24 aneurysms of 22 patients comprised 14 (59%) with complete occlusion, seven (29%) with a neck remnant, two (8%) with residual filling <50%, none with residual filling >50% and one (4%) unchanged in comparison to its pretreatment status. Postinterventional recanalizations were seen in three of 13 (23%) aneurysms treated with FD alone; none were observed in 15 aneurysms treated with adjunctive coiling. Conclusion Anatomic presentation and location are key for successful FD treatment. The rate of successful occlusion increases during follow-up. Postinterventional monitoring for at least six months is paramount, as anatomic outcome is not reliably predictable and recanalizations may occur in initially completely occluded aneurysms. PMID:26015522

  10. Using earth-tide induced water pressure changes to measure in situ permeability: A comparison with long-term pumping tests

    NASA Astrophysics Data System (ADS)

    Allègre, Vincent; Brodsky, Emily E.; Xue, Lian; Nale, Stephanie M.; Parker, Beth L.; Cherry, John A.

    2016-04-01

    Good constraints on hydrogeological properties are an important first step in any quantitative model of groundwater flow. Field estimation of permeability is difficult as it varies over orders of magnitude in natural systems and is scale-dependent. Here we directly compare permeabilities inferred from tidal responses with conventional large-scale, long-term pumping tests at the same site. Tidally induced water pressure changes recorded in wells are used to infer permeability at ten locations in a densely fractured sandstone unit. Each location is either an open-hole well or a port in a multilevel monitoring well. Tidal response is compared at each location to the results of two conventional, long-term and large scale pumping tests performed at the same site. We obtained consistent values between the methods for a range of site-specific permeabilities varying from ˜10-15 m2 to 10-13 m2 for both open wells with large open intervals and multilevel monitoring well. We conclude that the tidal analysis is able to capture passive and accurate estimates of permeability.

  11. Study on the installation method for the long-term observatory based on the field test during Chikyu Expedition 319

    NASA Astrophysics Data System (ADS)

    Kitada, K.; Araki, E.; Kimura, T.; Saffer, D. M.; Byrne, T.; McNeill, L. C.; Toczko, S.; Eguchi, N. O.; Takahashi, K.

    2009-12-01

    In future IODP expeditions, a series of long-term borehole observatories that combine elements of CORKs (e.g., ODP Leg 196 in the Nankai Trough) and NEREID (ODP Leg 186 at Japan Trench), will be installed into the three holes along the NanTroSEIZE transect offshore the Kii Peninsula of southern Honshu, Japan (Sites C0002, C0009 and C0010). The three boreholes are located within and above regions of contrasting behavior of the megasplay fault zone and plate boundary (i.e., a site ~6-7 km above the “locked” seismogenic plate boundary [Site C0009], a site above the updip edge of the locked zone [Site C0002], and a shallow site in the megasplay fault zone and footwall where slip is presumed to be aseismic [Site C0010]). These observatories aim to monitor seismic activity, slow slip behavior, and possibly interseismic strain accumulation at the plate boundary and megasplay faults across a range of pressure, temperature, and kinematic conditions. Currently, the planned observation system for the boreholes consists of an array of sensors designed to monitor slow crustal deformation (e.g., strain, tilt, and pore pressure as a proxy for strain), seismic events including very low frequency earthquakes, hydrologic transients associated with strain events, ambient pore pressure, and temperature. In order to realize these long-term borehole observatories, one of the primary challenges is to install high- precision, sensitive sensors into the borehole without damaging them. In particular, strong vibration can damage sensors during the lowering on drill pipe through the water column, especially in areas of strong ocean currents such as the Nankai Trough. During IODP Expedition 319 from May - August 2009 , we conducted a simulation of the planned future borehole sensor installation at Site C0010 after casing operations, as part of the preparation for long-term borehole observatories in future NanTroSEIZE expeditions. This test had two main objectives: (1) to evaluate

  12. Long-term consequences of non-intentional flows of substances: Modelling non-intentional flows of lead in the Dutch economic system and evaluating their environmental consequences

    SciTech Connect

    Elshkaki, Ayman Voet, Ester van der; Holderbeke, Mirja van; Timmermans, Veerle

    2009-06-15

    Substances may enter the economy and the environment through both intentional and non-intentional flows. These non-intentional flows, including the occurrence of substances as pollutants in mixed primary resources (metal ores, phosphate ores and fossil fuels) and their presence in re-used waste streams from intentional use may have environmental and economic consequences in terms of pollution and resource availability. On the one hand, these non-intentional flows may cause pollution problems. On the other hand, these flows have the potential to be a secondary source of substances. This article aims to quantify and model the non-intentional flows of lead, to evaluate their long-term environmental consequences, and compare these consequences to those of the intentional flows of lead. To meet this goal, the model combines all the sources of non-intentional flows of lead within one model, which also includes the intentional flows. Application of the model shows that the non-intentional flows of lead related to waste streams associated with intentional use are decreasing over time, due to the increased attention given to waste management. However, as contaminants in mixed primary resources application, lead flows are increasing as demand for these applications is increasing.

  13. OECD MCCI project long-term 2-D molten core concrete interaction test design report, Rev. 0. September 30, 2002.

    SciTech Connect

    Farmer, M. T.; Kilsdonk, D. J.; Lomperski, S.; Aeschliman, R. W.; Basu, S.

    2011-05-23

    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following two technical objectives: (1) resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of the first program objective, the Small-Scale Water Ingression and Crust Strength (SSWICS) test series has been initiated to provide fundamental information on the ability of water to ingress into cracks and fissures that form in the debris during quench, thereby augmenting the otherwise conduction-limited heat transfer process. A test plan for Melt Eruption Separate Effects Tests (MESET) has also been developed to provide information on the extent of crust growth and melt eruptions as a function of gas sparging rate under well-controlled experiment conditions. In terms of the second program objective, the project Management Board (MB) has approved startup activities required to carry out

  14. Evaluation of the resilience of a full-scale down-flow hanging sponge reactor to long-term outages at a sewage treatment plant in India.

    PubMed

    Onodera, Takashi; Takayama, Daisuke; Ohashi, Akiyoshi; Yamaguchi, Takashi; Uemura, Shigeki; Harada, Hideki

    2016-10-01

    Resilience to process outages is an essential requirement for sustainable wastewater treatment systems in developing countries. In this study, we evaluated the ability of a full-scale down-flow hanging sponge (DHS) reactor to recover after a 10-day outage. The DHS tested in this study uses polyurethane sponge as packing material. This full-scale DHS reactor has been tested over a period of about 4 years in India with a flow rate of 500 m(3)/day. Water was not supplied to the DHS reactor that was subjected to the 10-day outage; however, the biomass did not dry out because the sponge was able to retain enough water. Soon after the reactor was restarted, a small quantity of biomass, amounting to only 0.1% of the total retained biomass, was eluted. The DHS effluent achieved satisfactory removal of suspended solids, chemical oxygen demand, and ammonium nitrogen within 90, 45, and 90 min, respectively. Conversely, fecal coliforms in the DHS effluent did not reach satisfactory levels within 540 min; instead, the normal levels of fecal coliforms were achieved within 3 days. Overall, the tests demonstrated that the DHS reactor was sufficiently robust to withstand long-term outages and achieved steady state soon after restart. This reinforces the suitability of this technology for developing countries. PMID:27450993

  15. Cardiac-like flow generator for long-term imaging of endothelial cell responses to circulatory pulsatile flow at microscale.

    PubMed

    Chen, Huaying; Cornwell, James; Zhang, Han; Lim, Tse; Resurreccion, Rena; Port, Timothy; Rosengarten, Gary; Nordon, Robert E

    2013-08-01

    In vitro models of circulatory hemodynamics are required to mimic the microcirculation for study of endothelial cell responses to pulsatile shear stress by live cell imaging. This study reports the design, fabrication and characterisation of a microfluidic device that generates cardiac-like flow in a continuous culture system with a circulatory volume of only 2-3 μL. The device mimics a single chamber heart, with the following cardiac phases: (1) closure of the ventricle inlet valve, (2) contraction of the ventricle (systole) followed by opening of the outlet valve and (3) relaxation of the ventricle (diastole) with opening of the inlet valve whilst the outlet valve remains closed. Periodic valve states and ventricular contractions were actuated by microprocessor controlled pneumatics. The time-dependent velocity-field was characterised by micro-particle image velocimetry (μ-PIV). μ-PIV observations were used to help tune electronic timing of valve states and ventricular contractions for synthesis of an arterial pulse waveform to study the effect of pulsatile shear stress on bovine artery endothelial cells (BAECs). BAECs elongated and aligned with the direction of shear stress after 48 h of exposure to a pulsatile waveform with a maximum shear stress of 0.42 Pa. The threshold for BAECs alignment and elongation under steady (non-pulsatile) flow reported by Kadohama et al. (2006) is 0.7-1.4 Pa. These cells respond to transient shear stress because the time average shear stress of the pulse waveform to generate this morphological response was only 0.09 Pa, well below the steady flow threshold. The microfluidic pulse generator can simulate circulatory hemodynamics for live cell imaging of shear-induced signalling pathways. PMID:23727941

  16. Impact of long-term ranitidine and pantoprazole on accuracy of [13C]urea breath test.

    PubMed

    Dulbecco, Pietro; Gambaro, Camilla; Bilardi, Claudio; Zentilin, Patrizia; Mele, Maria Raffaella; Mansi, Carlo; Biagini, Riccardo; Tessieri, Laura; Iiritano, Elena; Usai, Paolo; Vigneri, Sergio; Savarino, Vincenzo

    2003-02-01

    No previous study has analyzed the impact of long-term antisecretory drugs on the precision of [13C]urea breath test (UBT). We assessed the rate of UBT conversion from positive to negative results during 60-day therapy with standard doses of ranitidine and pantoprazole. For this purpose, we recruited 60 dyspeptic patients with H. pylori infection ascertained on the basis of the concomitant results of CLO-test, histology, and UBT. Our patients were randomly assigned to receive ranitidine 300 mg at night or pantoprazole 40 mg in the morning for 60 days. UBT was performed at baseline and on days 14, 30, and 60, while patients were still taking antisecretory drugs. Patients with false-negative UBT on day 60 repeated the test every 3 days until conversion. After overnight fasting, duplicate breath test samples were taken from each patient before and 30 min after ingestion of 75 mg [13C]urea dissolved in 150 ml of 0.033 mol/liter citric acid. Four patients dropped out of the study. Both drugs induced similar false-negative UBTs on day 14 of dosing (P = 0.5). Afterwards, the three false-negative UBTs in the ranitidine group again became positive during therapy and particularly on day 30 of dosing. Of the four false-negative UBTs in the pantoprazole group at day 60, one became positive after 3 and three after 9 days of therapy cessation. Our findings show that the long-term use of ranitidine and pantoprazole at standard doses has different effects on the results of UBT. In the pantoprazole group patients again became positive within 3-9 days after stopping 60-day therapy, whereas in the ranitidine group patients reverted to positive on day 30 of dosing while they were still on treatment and this was likely due to development of tolerance. Therefore, patients taking pantoprazole need at least a 10-day withdrawal before UBT testing, while those taking ranitidine for at least 30 days can undergo UBT without the necessity of a wash-out period. PMID:12643609

  17. Long-term testing of the zinc titanate for desulfurization of hot coal gas in a fluidized-bed reactor

    SciTech Connect

    Jain, S.C.; Gupta, R.; Gangwal, S.K.

    1993-12-31

    Research Triangle Institute (RTI) under contract to the US Department of Energy (DOE), Morgantown energy Technology Center has recently completed a long-term test consisting of 100 sulfidation-regeneration cycles on a zinc titanate material intended for use as a high-temperature, regenerable sorbent to desulfurize coal-derived gas. The primary motivation for this development is to generate a more economical, environmentally superior, and reliable process to purify the product gas of coal gasifiers for use in gas turbines and fuel cells. This zinc titanate formulation (designated as ZT-4 and containing Zn-to-Ti in a molar ratio of 1.5) exhibited the best overall performance in terms of chemical reactivity, sulfur capacity, regenerability, structural properties and, most importantly, the attrition resistance based on multicycle testing of a number of sorbent formulations in a bench scale fluidized-bed reactor. The conditions in the test were -- desulfurization temperature: 750C (1382F); pressure: 1.52 MPa (220 psia); coal gas: simulated Texaco entrained-bed oxygen-blown gasifier gas containing 12,000 ppmv of H{sub 2}S; superficial gas velocity: 15 cm/s (0.49 ft/s). The ZT-4 sorbent used in this test was prepared using a granulation technique and 500 g of the sorbent in the 100 to 300 microns particle diameter range were used in a 5.1-cm (2-inch) i.d. stainless steel reactor.

  18. Preferential flow paths in paraglacial catchments: first order controls on the long-term stability of 'biodiversity hotspots' in a changing climate

    NASA Astrophysics Data System (ADS)

    Grocott, Michael; Kettridge, Nick; Bradley, Chris; Milner, Alexander

    2016-04-01

    PFPs are a fundamental first order control upon the occurrence of 'biodiversity hotspots' within paraglacial floodplains, and highlights their role as an important conduit for hillslope-floodplain connectivity. Given the expected changes in the hydrological dynamics of paraglacial catchments this research raises questions about the long-term stability of GW-fed streams, and whether the increasing relative importance of groundwater sources (e.g. from colluvium) can sustain flow of GW-fed streams. In addition glacial retreat and associated long-term declines in sediment yields could have negative implications for the development and renewal of PFPs across paraglacial floodplains, which would be detrimental to the persistence of 'biodiversity hotspots'.

  19. HYPOXIA IN CHESAPEAKE BAY, 1950-2001: LONG-TERM CHANGE IN RELATION TO NUTRIENT LOADING AND RIVER FLOW

    EPA Science Inventory

    A 52-yr record of dissolved oxygen in Chesapeake Bay (1950 to 2001) and a record of nitrate (NO3-) loading by the Susquehanna River spanning a longer period (1903, 1945 to 2001) were assembled to describe the long-term pattern of hypoxia and anoxia in Chesapeake Bay an...

  20. Testing promotes long-term learning via stabilizing activation patterns in a large network of brain areas.

    PubMed

    Keresztes, Attila; Kaiser, Daniel; Kovács, Gyula; Racsmány, Mihály

    2014-11-01

    The testing effect refers to the phenomenon that repeated retrieval of memories promotes better long-term retention than repeated study. To investigate the neural correlates of the testing effect, we used event-related functional magnetic resonance imaging methods while participants performed a cued recall task. Prior to the neuroimaging experiment, participants learned Swahili-German word pairs, then half of the word pairs were repeatedly studied, whereas the other half were repeatedly tested. For half of the participants, the neuroimaging experiment was performed immediately after the learning phase; a 1-week retention interval was inserted for the other half of the participants. We found that a large network of areas identified in a separate 2-back functional localizer scan were active during the final recall of the word pair associations. Importantly, the learning strategy (retest or restudy) of the word pairs determined the manner in which the retention interval affected the activations within this network. Recall of previously restudied memories was accompanied by reduced activation within this network at long retention intervals, but no reduction was observed for previously retested memories. We suggest that retrieval promotes learning via stabilizing cue-related activation patterns in a network of areas usually associated with cognitive and attentional control functions. PMID:23796945

  1. Analytical electron microscopy examination of solid reaction products in long-term test of SRL 200 waste glasses

    SciTech Connect

    Buck, E.C.; Fortner, J.A.; Bates, J.K.; Feng, X.; Dietz, N.L.; Bradley, C.R.; Tani, B.S.

    1993-12-31

    Alteration phases, found on the leached surfaces and present as colloids in the leachates of 200-based frit (fully active and simulated) nuclear waste glass, reacted under static test conditions, at a surface area to leachate volume ratio of 20,000 m{sup {minus}1} for 15 days to 728 days, have been examined by analytical electron microscopy. The compositions of the secondary phases were determined using x-ray energy dispersive spectroscopy and electron energy loss spectroscopy, and structural analysis was accomplished by electron diffraction. Long-term samples of simulated glass, which had undergone an acceleration of reaction after 182 days, possessed a number of silicate secondary phases, including; smectite (iron silicate and potassium iron alumina-silicate, weeksite (uranium silicate), zeolite (calcium potassium alumino-silicate), tobermorite (calcium silicate), and a pure silica phase. However, uranium silicates and smectite have also been observed in tests, which have not undergone the acceleration of reaction, in both the leachate and leached layer, suggesting that these phases are not responsible for the acceleration of reaction.

  2. A test-retest dataset for assessing long-term reliability of brain morphology and resting-state brain activity.

    PubMed

    Huang, Lijie; Huang, Taicheng; Zhen, Zonglei; Liu, Jia

    2016-01-01

    We present a test-retest dataset for evaluation of long-term reliability of measures from structural and resting-state functional magnetic resonance imaging (sMRI and rfMRI) scans. The repeated scan dataset was collected from 61 healthy adults in two sessions using highly similar imaging parameters at an interval of 103-189 days. However, as the imaging parameters were not completely identical, the reliability estimated from this dataset shall reflect the lower bounds of the true reliability of sMRI/rfMRI measures. Furthermore, in conjunction with other test-retest datasets, our dataset may help explore the impact of different imaging parameters on reliability of sMRI/rfMRI measures, which is especially critical for assessing datasets collected from multiple centers. In addition, intelligence quotient (IQ) was measured for each participant using Raven's Advanced Progressive Matrices. The data can thus be used for purposes other than assessing reliability of sMRI/rfMRI alone. For example, data from each single session could be used to associate structural and functional measures of the brain with the IQ metrics to explore brain-IQ association. PMID:26978040

  3. A test-retest dataset for assessing long-term reliability of brain morphology and resting-state brain activity

    PubMed Central

    Huang, Lijie; Huang, Taicheng; Zhen, Zonglei; Liu, Jia

    2016-01-01

    We present a test-retest dataset for evaluation of long-term reliability of measures from structural and resting-state functional magnetic resonance imaging (sMRI and rfMRI) scans. The repeated scan dataset was collected from 61 healthy adults in two sessions using highly similar imaging parameters at an interval of 103–189 days. However, as the imaging parameters were not completely identical, the reliability estimated from this dataset shall reflect the lower bounds of the true reliability of sMRI/rfMRI measures. Furthermore, in conjunction with other test-retest datasets, our dataset may help explore the impact of different imaging parameters on reliability of sMRI/rfMRI measures, which is especially critical for assessing datasets collected from multiple centers. In addition, intelligence quotient (IQ) was measured for each participant using Raven’s Advanced Progressive Matrices. The data can thus be used for purposes other than assessing reliability of sMRI/rfMRI alone. For example, data from each single session could be used to associate structural and functional measures of the brain with the IQ metrics to explore brain-IQ association. PMID:26978040

  4. Testing the generalized complementary relationship of evaporation with continental-scale long-term water-balance data

    NASA Astrophysics Data System (ADS)

    Szilagyi, Jozsef; Crago, Richard; Qualls, Russell J.

    2016-09-01

    The original and revised versions of the generalized complementary relationship (GCR) of evaporation (ET) were tested with six-digit Hydrologic Unit Code (HUC6) level long-term (1981-2010) water-balance data (sample size of 334). The two versions of the GCR were calibrated with Parameter-Elevation Regressions on Independent Slopes Model (PRISM) mean annual precipitation (P) data and validated against water-balance ET (ETwb) as the difference of mean annual HUC6-averaged P and United States Geological Survey HUC6 runoff (Q) rates. The original GCR overestimates P in about 18% of the PRISM grid points covering the contiguous United States in contrast with 12% of the revised version. With HUC6-averaged data the original version has a bias of -25 mm yr-1 vs the revised version's -17 mm yr-1, and it tends to more significantly underestimate ETwb at high values than the revised one (slope of the best fit line is 0.78 vs 0.91). At the same time it slightly outperforms the revised version in terms of the linear correlation coefficient (0.94 vs 0.93) and the root-mean-square error (90 vs 92 mm yr-1).

  5. Long-term retention of a divided attention psycho-motor test combining choice reaction test and postural balance test: A preliminary study.

    PubMed

    Rossi, R; Pascolo, P B

    2015-09-01

    Driving in degraded psychophysical conditions, such as under the influence of alcohol or drugs but also in a state of fatigue or drowsiness, is a growing problem. The current roadside tests used for detecting drugs from drivers suffer various limitations, while impairment is subjective and does not necessarily correlate with drug metabolite concentration found in body fluids. This work is a validation step towards the study of feasibility of a novel test conceived to assess psychophysical conditions of individuals performing at-risk activities. Motor gestures, long-term retention and learning phase related to the protocol are analysed in unimpaired subjects. The protocol is a divided attention test, which combines a critical tracking test achieved with postural movements and a visual choice reaction test. Ten healthy subjects participated in a first set of trials and in a second set after about six months. Each session required the carrying out of the test for ten times in order to investigate learning effect and performance over repetitions. In the first set the subjects showed a learning trend up to the third trial, whilst in the second set of trials they showed motor retention. Nevertheless, the overall performance did not significantly improve. Gestures are probably retained due to the type of tasks and the way in which the instructions are conveyed to the subjects. Moreover, motor retention after a short training suggests that the protocol is easy to learn and understand. Implications for roadside test usage and comparison with current tests are also discussed. PMID:26070019

  6. Comparative test of ecological assessment methods of lowland streams based on long-term monitoring data of macrophytes.

    PubMed

    Wiegleb, Gerhard; Gebler, Daniel; van de Weyer, Klaus; Birk, Sebastian

    2016-01-15

    Ecological assessment of water courses is required by the European Water Framework Directive (WFD). Assessment by means of macrophytes is impeded by insufficient knowledge on the relations between assessment scores and the dynamics of environmental parameters. Data from a long-term observation of macrophyte dynamics over 21 years in two lowland rivers were used for testing the performance of six widely used assessment methods. Six sample sites situated in two lowland streams were selected. Four sites were classified as of moderate habitat quality and two sites as of poor habitat quality in the context of WFD. Assessment methods generally showed a poor performance in recognizing the ecological status of the annual observations. Status was more often over- than underestimated. Performance of methods differed among individual rivers and among river zones. Assessment scores mostly showed a steady decline, even though all sites obviously remained in the same habitat quality class throughout the observation period. Variation of most environmental factors was largely unrelated to assessment scores. Fluctuations of assessment scores were partly related to single natural disturbance events such as high discharge. Increased shading by marginal trees was reflected negatively by most assessment scores. Assessment scores were highly correlated with species richness and total abundance. The best overall performance was shown by the North-Rhine Westphalian (NRW) method. In contrast to single metric methods it can be adapted to individual properties of a reach in a flexible way. Macrophyte assessment based on the pressure-impact framework did not lead to a satisfying result in our case study. Improvement of species assessment scores and inclusion of functional properties such as growth form may help to overcome the present difficulties. PMID:26476066

  7. Development of testing and analysis methodology to assess the long term durability of polymeric composites at high temperatures

    NASA Technical Reports Server (NTRS)

    Johnson, W. Steven

    1990-01-01

    A workshop was held to help assess the state-of-the-art in evaluating the long term durability of polymeric matrix composites (PMCs) and to recommend future activities. Design and evaluation of PMCs at elevated temperatures were discussed. The workshop presentations, the findings of the workshop sessions are briefly summarized.

  8. Testing the Long-Term Efficacy of a Prevention Program for Improving Marital Conflict in Community Families

    ERIC Educational Resources Information Center

    Faircloth, W. Brad; Schermerhorn, Alice C.; Mitchell, Patricia M.; Cummings, Jennifer S.; Cummings, E. Mark

    2011-01-01

    Family-focused prevention programs for community samples have potentially broad, clinically relevant implications but few studies have examined whether any program benefits continue to be observed over the long term. Although benefits of a marital conflict focused parent education program, the Happy Couples and Happy Kids (i.e., HCHK) program,…

  9. Multiple pollutant removal using the condensing heat exchanger: Phase 1 final report, November 1995--June 1997. Addendum 2: Task 3 topical report -- Long term wear test

    SciTech Connect

    Kudlac, G.A.

    1998-06-01

    Long-term operation of a condensing heat exchanger under typical coal-fired flue gas conditions was investigated in Phase 1, Task 3 of the Multiple Pollutant Removal Using the Condensing Heat Exchanger test program. The specific goal of this task was to determine the amount of wear, if any, on the Teflon{reg_sign}-covered heat transfer tubes in a condensing heat exchanger. A pilot-scale single-stage condensing heat exchanger (CHX{reg_sign}) was operated under typical coal-fired flue gas conditions on a continuous basis for a period of approximately 10 months. Operating conditions and particulate loadings for the test unit were monitored, Teflon{reg_sign} film thickness measurements were conducted, and surface replications (which duplicate the surface finish at the microscopic level) were taken at various times during the test. Data from the test indicate that virtually no decrease in Teflon{reg_sign} thickness was observed for the coating on the first two rows of heat exchanger tubes, even at high inlet particulate loadings (400 mg/dscm [0.35 lb/10{sup 6} Btu]). Evidence of wear was present only at the microscopic level, and even then was very minor in severity. Operation at high inlet particulate loadings resulted in accumulated ash deposits within the heat exchanger. Installation of a modified (higher flow rate) wash nozzle manifold substantially reduced subsequent deposit formation.

  10. Long-term in vivo carcinogenicity test of potassium bromate, sodium hypochlorite, and sodium chlorite conducted in Japan

    SciTech Connect

    Kurokawa, Y.; Takayama, S.; Konishi, Y.; Hiasa, Y.; Asahina, S.; Takahashi, M.; Maekawa, A.; Hayashi, Y.

    1986-11-01

    Long-term in vivo carcinogenicity tests of potassium bromate (KBrO/sub 3/), sodium hypochlorite (NaClO) and sodium chlorite (NaClO/sub 2/) have been conducted in Japan from 1977 to 1985. In these investigations, groups of approximately 50 male and 50 female F344 rats or B6C3F1 mice were given solutions of the compounds as their drinking water ad libitum at two dose levels determined on the basis of preliminary 13-weeks tests. The carcinogenic potential of KBrO/sub 3/ was tested by administering doses of 500 or 250 ppm to rats for 110 weeks. Significantly elevated incidences of renal cell tumors in males and females and mesotheliomas of the peritoneum in males as compared to controls were observed. When female mice were given KBrO/sub 3/ at doses of 1000 or 500 ppm for 78 weeks, no significant differences in tumor incidences between experimental and control groups were apparent. The incidences of tumors in NaClO-treated and control animals of both sexes were not significantly different in both rat and mouse studies. No statistically significant differences were observed in the incidences of tumor formation between NaClO/sub 2/-treated and control groups of rats male mice, the combined incidences of hyperplastic nodules and hepatocellular carcinomas of the liver in a low-dose group, and adenomas and adenocarcinomas of the lung in a high-dose group, were marginally increased compared to controls. The authors concluded that KBrO/sub 2/ was carcinogenic in rats of both sexes. NaClO was not carcinogenic in either rats and or mice under the conditions of the present studies. Although NaClO/sub 2/ was shown to be noncarcinogenic in rats, the results for mice were evaluated as inconclusive. Also the results of two-stage mouse skin carcinogenesis using KBrO/sub 3/, NaClO, and NaClO/sub 2/ are presented.

  11. The long-term benefits of genotypic resistance testing in patients with extensive prior antiretroviral therapy: a model-based approach

    PubMed Central

    Yazdanpanah, Y; Vray, M; Meynard, J; Losina, E; Weinstein, MC; Morand-Joubert, L; Goldie, SJ; Hsu, HE; Walensky, RP; Dalban, C; Sax, PE; Girard, PM; Freedberg, KA

    2008-01-01

    Objectives Resistance testing in HIV disease may provide long-term benefits that are not evident from short-term data. Our objectives were to estimate the long-term effectiveness, cost and cost-effectiveness of genotype testing in patients with extensive antiretroviral exposure. Methods We used an HIV simulation model to estimate the long-term effectiveness and cost-effectiveness of genotype testing. Clinical data incorporated into the model were from NARVAL, a randomized trial of resistance testing in patients with extensive antiretroviral exposure, and other randomized trials. Each simulated patient was eligible for up to three sequential regimens of antiretroviral therapy (i.e. two additional regimens beyond the trial-based regimen) using drugs not available at the time of the study, such as lopinavir/ritonavir, darunavir/ritonavir and enfuvirtide. Results In the long term, projected undiscounted life expectancy increased from 132.2 months with clinical judgement alone to 147.9 months with genotype testing. Median survival was estimated at 11.9 years in the resistance testing arm vs 10.4 years in the clinical judgement alone arm. Because of increased survival, the projected lifetime discounted cost of genotype testing was greater than for clinical judgement alone (€313 900 vs €263100; US$399 000 vs US$334 400). Genotype testing cost €69 600 (US$88 500) per quality-adjusted life year gained compared with clinical judgement alone. Conclusions In patients with extensive prior antiretroviral exposure, genotype testing is likely to increase life expectancy in the long term as a result of the increased likelihood of receiving two active new drugs. Genotype testing is associated with cost-effectiveness comparable to that of strategies accepted in patients with advanced HIV disease, such as enfuvirtide use. PMID:17760736

  12. Phenotypic characteristics of three human non-Hodgkin lymphoma lines: flow cytometric analysis after long-term maintenance.

    PubMed Central

    Kopper, L; Bánkfalvi, A; Mihalik, R; Páloczi, K; Benczur, M; Lapis, K

    1988-01-01

    Three human non-Hodgkin lymphomas of B-cell origin have been maintained as xenografts in artificially immunosuppressed mice. The long-term maintenance (3-5 years) resulted in no significant change in the morphology, DNA-index or cell surface markers of the tumors. Immunophenotyping revealed many similarities in the morphologically distinct lines. Light chain (lambda) restriction appeared in two lines (HT 58 and 130), but in the third line (HT 117) the co-expression of both light chains indicated the origin from light chain 'uncommitted' B cells. HT 117 was also different, expressing high transferrin-receptor activity, although it proliferates with practically the same rate as the other two lines. This study confirms the value of the xenograft system to approaching many tumor-specific problems. Images Fig. 1 PMID:3224446

  13. A Nonlinear Dynamic Approach Reveals a Long-Term Stroke Effect on Cerebral Blood Flow Regulation at Multiple Time Scales

    PubMed Central

    Hu, Kun; Lo, Men-Tzung; Peng, Chung-Kang; Liu, Yanhui; Novak, Vera

    2012-01-01

    Cerebral autoregulation (CA) is an important vascular control mechanism responsible for relatively stable cerebral blood flow despite changes of systemic blood pressure (BP). Impaired CA may leave brain tissue unprotected against potentially harmful effects of BP fluctuations. It is generally accepted that CA is less effective or even inactive at frequencies >∼0.1 Hz. Without any physiological foundation, this concept is based on studies that quantified the coupling between BP and cerebral blood flow velocity (BFV) using transfer function analysis. This traditional analysis assumes stationary oscillations with constant amplitude and period, and may be unreliable or even invalid for analysis of nonstationary BP and BFV signals. In this study we propose a novel computational tool for CA assessment that is based on nonlinear dynamic theory without the assumption of stationary signals. Using this method, we studied BP and BFV recordings collected from 39 patients with chronic ischemic infarctions and 40 age-matched non-stroke subjects during baseline resting conditions. The active CA function in non-stroke subjects was associated with an advanced phase in BFV oscillations compared to BP oscillations at frequencies from ∼0.02 to 0.38 Hz. The phase shift was reduced in stroke patients even at > = 6 months after stroke, and the reduction was consistent at all tested frequencies and in both stroke and non-stroke hemispheres. These results provide strong evidence that CA may be active in a much wider frequency region than previously believed and that the altered multiscale CA in different vascular territories following stroke may have important clinical implications for post-stroke recovery. Moreover, the stroke effects on multiscale cerebral blood flow regulation could not be detected by transfer function analysis, suggesting that nonlinear approaches without the assumption of stationarity are more sensitive for the assessment of the coupling of nonstationary

  14. Long-Term Performance of Transuranic Waste Inadvertently Disposed in a Shallow Land Burial Trench at the Nevada Test Site

    SciTech Connect

    Gregory J. Shott; Vefa Yucel

    2009-07-16

    In 1986, 21 m3 of transuranic (TRU) waste was inadvertently disposed in a shallow land burial trench at the Area 5 Radioactive Waste Management Site on the Nevada Test Site. U.S. Department of Energy (DOE) TRU waste must be disposed in accordance with Title 40, Code of Federal Regulations (CFR), Part 191, Environmental Radiation Protection Standard for Management and Disposal of Spent Nuclear Fuel, High-Level, and Transuranic Radioactive Wastes. The Waste Isolation Pilot Plant is the only facility meeting these requirements. The National Research Council, however, has found that exhumation of buried TRU waste for disposal in a deep geologic repository may not be warranted when the effort, exposures, and expense of retrieval are not commensurate with the risk reduction achieved. The long-term risks of leaving the TRU waste in-place are evaluated in two probabilistic performance assessments. A composite analysis, assessing the dose from all disposed waste and interacting sources of residual contamination, estimates an annual total effective dose equivalent (TEDE) of 0.01 mSv, or 3 percent of the dose constraint. A 40 CFR 191 performance assessment also indicates there is reasonable assurance of meeting all requirements. The 40 CFR 191.15 annual mean TEDE for a member of the public is estimated to reach a maximum of 0.055 mSv at 10,000 years, or approximately 37 percent of the 0.15 mSv individual protection requirement. In both assessments greater than 99 percent of the dose is from co-disposed low-level waste. The simulated probability of the 40 CFR 191.13 cumulative release exceeding 1 and 10 times the release limit is estimated to be 0.0093 and less than 0.0001, respectively. Site characterization data and hydrologic process modeling support a conclusion of no groundwater pathway within 10,000 years. Monte Carlo uncertainty analysis indicates that there is reasonable assurance of meeting all regulatory requirements. Sensitivity analysis indicates that the results

  15. The Impact of Structure on Word Meaning and Fill-in-The-Blank Tests Procedures on Short-Term and Long-Term Retention of Vocabulary Items

    ERIC Educational Resources Information Center

    Fazeli, Seyed Hossein

    2009-01-01

    The purpose of research described in the current study to investigate the impact of structure knowing on two types of test, i.e. word-meaning test and fill-in-the-blank test, their correlation and procedures on both short-term and long-term retention of vocabulary items. The importance of the present study, to test the condition that learners are…

  16. Short and long-term tests of elastomers with hot hostile fluids. Environmental Compatibility Test Program final report

    SciTech Connect

    Friese, G.J.

    1982-12-30

    Equipment manufacturers and elastomer houses were called to find the best currently available high-temperature elastomers. Tensile specimens of 46 such compounds were immersion tested for five days in six 190C fluids of interest: isobutane, brine, ASTM No. 1 oil, ASTM No. 3 oil, Pacer DHT-185M synthetic oil, and Chevron Cylinder Grade 460X oil. The best eight were selected based upon the least change in mechanical properties. These eight were then simultaneously tested (a) by immersion in five 190C fluids for six months and (b) as 0-rings for 46 hours at 190C, 230C, and 265C (accelerated ageing) in three fluids and at a differential pressure of 21 MPa. Based upon these 0-ring tests, four compounds were selected for testing as 0-rings in three 204C fluids at 21 MPa differential pressure. The data were evaluated and conclusions were drawn. Conclusions and recommendations are provided. There was immersion testing of primarily L'Garde compounds in brine and CL3 mineral oil for 6 months at 190C. L'Garde had formulated several compounds specifically for 260C brine, and their applicability to a specific problem was assessed early in the program.

  17. A SERENDIPITOUS, LONG-TERM INFILTRATION EXPERIMENT: WATER AND RADIONUCLIDE CIRCULATION BENEATH THE CAMBRIC TRENCH AT THE NEVADA TEST SITE.

    SciTech Connect

    Maxwell, R; Tompson, A; Carle, S; Zavarin, M; Kollet, S

    2006-03-16

    Underground atomic weapons testing at the Nevada Test Site introduced numerous radionuclides that may be used to characterize subsurface hydrologic transport processes in arid climates. Beginning in 1975, groundwater adjacent to the CAMBRIC test, conducted beneath Frenchman Flat in 1965, was pumped steadily for 16 years to elicit experimental information on the migration of residual radioactivity through the saturated zone. Radionuclides in the pumping well effluent, including tritium, {sup 36}Cl and {sup 85}Kr, were extensively monitored prior to their discharge into an unlined ditch flowing toward a dry lake bed over a kilometer away. We have applied a large (6km x 6km x 1km) and highly resolved (4 m) variably saturated flow model to investigate infiltration into the 220-m vadose zone underlying the ditch as well as subsequent groundwater recharge and well recirculation processes. A Lagrangian particle-tracking model has been used to compute flow pathways and estimate radionuclide travel and residence times in various parts of the system based upon the flow model. Results are consistent with rising tritium levels observed in a monitoring well since 1991. They suggest that recirculation of the ditch effluent through the vadose zone, into groundwater, and back to the test cavity and pumping well are responsible for diluted, tritium-based groundwater age dates observed in 2000 at these locations, as well as for increased tailing effects observed in the pumping well elution curves. Altogether, the models and experimental observations provide an improved basis to understand both historical and future movements of test-related radionuclides in groundwater near CAMBRIC.

  18. Long-term in vivo carcinogenicity tests of potassium bromate, sodium hypochlorite, and sodium chlorite conducted in Japan.

    PubMed Central

    Kurokawa, Y; Takayama, S; Konishi, Y; Hiasa, Y; Asahina, S; Takahashi, M; Maekawa, A; Hayashi, Y

    1986-01-01

    Long-term in vivo carcinogenicity tests of potassium bromate (KBrO3), sodium hypochlorite (NaClO), and sodium chlorite (NaClO2) have been conducted in Japan from 1977 to 1985. In these investigations, groups of approximately 50 male and 50 female F344 rats or B6C3F1 mice were given solutions of the compounds as their drinking water ad libitum at two dose levels determined on the basis of preliminary 13-week tests. Control animals were given distilled water. The carcinogenic potential of KBrO3 was tested by administering doses of 500 or 250 ppm to rats for 110 weeks. Significantly elevated incidences of renal cell tumors in males and females and mesotheliomas of the peritoneum in males as compared to controls were observed. When female mice were given KBrO3 at doses of 1000 or 500 ppm for 78 weeks, no significant differences in tumor incidences between experimental and control groups were apparent. NaClO was administered to male and female rats, respectively, at doses of 1000 or 500 ppm and 2000 or 1000 ppm for 104 weeks. In mice, NaClO was given at doses of 1000 or 500 ppm to either sex for 103 weeks. The incidences of tumors in NaClO-treated and control animals of both sexes were not significantly different in both rat and mouse studies. NaClO2 was given to rats of both sexes at a dose of 600 or 300 ppm for 85 weeks. No statistically significant differences were observed in the incidences of tumor formation between NaClO2-treated and control groups of both sexes. NaClO2 was administered to mice at a concentration of 500 or 250 ppm for 85 weeks. In males, the combined incidences of hyperplastic nodules and hepatocellular carcinomas of the liver in a low-dose group, and adenomas and adenocarcinomas of the lung in a high-dose group, were marginally increased compared to controls (p less than 0.05). However, these incidences in treated males were within the range of values of historical control data in our program. We concluded that KBrO3 was carcinogenic in rats of

  19. Laser Doppler monitoring of alterations of blood-flow parameters in fish embryos in response to light irradiation: study of long-term and short-term reactions

    NASA Astrophysics Data System (ADS)

    Savchenko, Natalia B.; Priezzhev, Alexander V.; Revutsky, Pavel V.; Levenko, Borislav A.

    1997-05-01

    In this paper new experimental results on monitoring of alterations of blood flow parameters in growing fish embryos under laser and non-laser light irradiation are discussed. The measurements were performed by means of laser Doppler technique with high temporal and spatial resolution. Two parameters of blood flows were mostly measured: average velocity and frequency of velocity pulsations. These parameters were shown to be an adequate characteristics of nonstationary blood flows in fishes. The problem of noninvasivity of such experiments is discussed. For this purpose absorption spectra of fish embryos were measured. The quantitative response of blood flows to irradiation at different light wavelengths was recorded. Different species of fishes were used to compare the responses. Different effects were recorded which depend upon the doze and the wavelength of irradiation, and upon the stage of the embryo development at which the irradiation had taken place. Among those effects long-term and short-term reactions can be distinguished.

  20. Simulation of Flow and Long-Term Plutonium (Pu) Transport in the Vadose Zone at the Savannah River National Laboratory (SRNL)

    NASA Astrophysics Data System (ADS)

    Demirkanli, I.; Molz, F. J.; Kaplan, D. I.; Fjeld, R. A.; Serkiz, S. M.

    2006-05-01

    An improved understanding of flow and radionuclide transport in vadose zone sediments is fundamental to all types of future planning involving radioactive materials. One way to obtain such understanding is to perform long-term experimental studies of Pu transport in complex natural systems. With this in mind, a series of field experiments were initiated at the SRNL in the early 1980s. Lysimeters containing sources of different Pu oxidation states were placed in the shallow subsurface and left open to the natural environment for 2 to 11 years. At the end of the experiments, Pu activities were measured along vertical cores obtained from the lysimeters. Pu distributions were anomalous in nature, with transport from oxidized Pu sources being less than expected, and a small fraction of Pu from reduced sources moving more. Laboratory studies with lysimeter sediments suggested that surface-mediated, oxidation/reduction (redox) reactions could be responsible for the anomalous behavior, and this hypothesis is tested by performing both steady-state and transient Pu transport simulations that include retardation along with first-order redox reactions on mineral surfaces. Based on the simulations, we conclude that the surface-mediated, redox hypothesis is consistent with the observed downward Pu activity profiles in the experiments, and such profiles are captured well by a steady-state, net downward, flow model. (Discussion is presented as to why a steady model appears to work in a highly transient flow environment.) The redox model explains how Pu(V/VI) sources release activity that moves downward more slowly than expected based on adsorptive retardation alone, and how Pu(III/IV) sources result in a small fraction of activity that moves downward more rapidly than expected. The calibrated parameter values were robust and relatively well-defined throughout all four sets of simulations. Pu(V/VI) (i.e., oxidized Pu)retardation factors were about 15, and reduced Pu

  1. Significance and function of different spinal collateral compartments following thoracic aortic surgery: immediate versus long-term flow compensation.

    PubMed

    Meffert, Philipp; Bischoff, Moritz S; Brenner, Robert; Siepe, Matthias; Beyersdorf, Friedhelm; Kari, Fabian A

    2014-05-01

    Iatrogenic paraplegia has been accompanying cardiovascular surgery since its beginning. As a result, surgeons have been developing many theories about the exact mechanisms of this devastating complication. Thus, the impact of single arteries that contribute to the spinal perfusion is one of the most discussed subjects in modern surgery. The subsequent decision of reattachment or the permanent disconnection of these intercostal arteries divides the surgical community. On the one hand, the anatomical or vascular approach pleads for the immediate reimplantation to reconstruct the anatomical situation. On the other hand, the decision of the permanent disconnection aims at avoiding stealing phenomenon away from the spinal vascular network. This spinal collateral network can be described as consisting of three components-the intraspinal and two paraspinal compartments-that feed the nutrient arteries of the spinal cord. The exact functional impact of the different compartments of the collateral network remains poorly understood. In this review, the function of the intraspinal compartment in the context of collateral network principle as an immediate emergency backup system is described. The exact structure and architectural principles of the intraspinal compartment are described. The critical parameters with regard to the risk of postoperative spinal cord ischaemia are the number of anterior radiculomedullary arteries (ARMAs) and the distance between them in relation to the longitudinal extent of aortic disease. The paraspinal network as a sleeping reserve is proposed as the long-term backup system. This sleeping reserve has to be activated by arteriogenic stimuli. These are presented briefly, and prior findings regarding arteriogenesis are discussed in the light of the collateral network concept. Finally, the role of preoperative visualization of the ARMAs in order to evaluate the risk of postoperative paraplegia is emphasized. PMID:24078102

  2. Long-term agroecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed flow data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flow monitoring in Goodwater Creek Experimental Watershed started in 1971 at three nested watersheds ranging from 12 to 73 km2 in drainage area. Since then, flow has been measured at 14 plots, 3 fields, and 12 additional stream sites ranging from 0.0034 to 6067 km2 in the Central Mississippi River B...

  3. Long term water flow scenario in low-level waste disposal vaults, with particular regard to concrete structures in El Cabril, Cordoba, Spain

    NASA Astrophysics Data System (ADS)

    Zuloaga, P.; Andrade, C.; Saaltink, M. W.

    2006-11-01

    This paper deals with the main durability design objectives adopted for the Spanish Low-level waste disposal facility of El Cabril. The presentation summarizes the studies and models developed to represent the performance of the reinforced concrete vaults. Particular attention is paid to recent developments in modelling the water flow through the disposal system and its humidity saturation and their relation to the long term behaviour of the concrete barriers. It also describes the work being carried out to improve the existing models as a part of the required effort to maintain up to date the performance assessment of the facility.

  4. Long-term variations in the intensity of polar cap plasma flows inferred from SuperDARN

    NASA Astrophysics Data System (ADS)

    Koustov, A. V.; Fiori, R. A. D.; Abooali zadeh, Z.

    2015-11-01

    Multiyear (1995-2013) velocity data collected by the Super Dual Auroral Network (SuperDARN) HF radars are considered to investigate the diurnal, seasonal, and solar cycle variation of the polar cap plasma flow speed. By considering monthly data sets, we show that the flows are systematically faster in the dawn/prenoon sector. The effect is particularly strong for interplanetary magnetic field (IMF) Bz < 0, By > 0 and in summer months. For Bz < 0, the flow speed increases with intensification of the IMF transverse component Bt at a rate of 20-30 m/s/nT during near noon summer hours. The dependence is weaker for other seasons and away from noon. For IMF Bz > 0, the flow speed response to the increase in Bt is weak. Despite the general sensitivity of the flow speed to Bt intensity and season, the speed for specific IMF bins and seasons or the speed averaged over a year does not change much over the solar cycle. Overall, the velocity is reduced during years of lowest solar activity, but a progression of the effect throughout the solar cycle was not observed. Inferred diurnal and seasonal trends of the polar cap flow speed are generally consistent with variations in the occurrence of VHF echoes whose onset depends on the strength of the ionospheric electric field or equivalently the magnitude of the plasma flow speed.

  5. Unprotected sex following HIV testing among women in Uganda and Zimbabwe: short- and long-term comparisons with pre-test behaviour

    PubMed Central

    Turner, Abigail Norris; Miller, William C; Padian, Nancy S; Kaufman, Jay S; Behets, Frieda M; Chipato, Tsungai; Mmiro, Francis A; Salata, Robert A; Morrison, Charles S

    2009-01-01

    Background Despite widespread condom promotion for HIV prevention, prospective measurement of condom use before and after HIV testing is infrequent. Methods We analysed data from a prospective study of hormonal contraception and HIV acquisition among Zimbabwean and Ugandan women (1999–2004), in which HIV testing and counselling were performed approximately every 3 months. We used zero-inflated negative binomial (ZINB) models to examine the number and proportion of unprotected sex acts, comparing behaviour reported 2–6 months before HIV testing with behaviour reported both 2–6 months (short-term analysis) and 12–16 months (long-term analysis) after HIV testing. Results Short- and long-term analyses were similar, so we present only long-term findings from 151 HIV-infected and 650 uninfected participants. The proportion of HIV-infected women reporting any unprotected acts in a typical month declined from 74% (pre-infection behaviour) to 56% (12–16 months after HIV diagnosis). In multivariable models, HIV-infected women were twice as likely to report that all sex acts were protected by condoms after diagnosis compared with beforehand [adjusted odds ratio (aOR): 1.99, 95% confidence interval (CI): 1.12–3.53]; uninfected women were somewhat less likely to report that all acts were protected (aOR: 0.82, 95% CI: 0.64–1.04). HIV-infected women also reduced their number of unprotected acts by 38% (95% CI: −16 to −55%). However, their proportion of unprotected acts changed little (7% reduction, 95% CI: −18 to + 6%). Uninfected women reported little change in number or proportion of unprotected acts over the same time period. Conclusions HIV-infected women reduced the number, but not the proportion, of unprotected acts. HIV-negative women did not increase condom use after testing and counselling, but neither did they decrease condom use, suggesting that testing negative was not interpreted as endorsement of risky behaviour. PMID:19349481

  6. Test-Retest Reliability of 10 Hz Conditioning Electrical Stimulation Inducing Long-Term Potentiation (LTP)-Like Pain Amplification in Humans

    PubMed Central

    Xia, Weiwei; Mørch, Carsten Dahl; Andersen, Ole Kæseler

    2016-01-01

    Background 10 Hz conditioning electrical stimulation (CES) has been shown to induce long-term potentiation (LTP)-like pain amplification similar to traditional 100 Hz CES in healthy humans. The aim of this study was to assess the test-retest reliability and to estimate sample sizes required for future crossover and parallel study designs. Methods The 10 Hz paradigm (500 rectangular pulses lasting 50 s) was repeated on two separate days with one week interval in twenty volunteers. Perceptual intensities to single electrical stimulation (SES) at the conditioned skin site and to mechanical stimuli (pinprick and light stroking) in immediate vicinity to the conditioned skin site were recorded. Superficial blood flow (SBF) was assessed as indicator of neurogenic inflammation. All outcome measures were assessed with 10 min interval three times before and six times after the CES. The coefficient of variation and intra-class correlation coefficient were calculated within session and between sessions. Sample sizes were estimated for future crossover (Ncr) and parallel (Np) drug testing studies expected to detect a 30% decrease for the individual outcome measure following 10 Hz CES. Results Perceptual intensity ratings to light stroking (Ncr = 2, Np = 33) and pinprick stimulation (491 mN) (Ncr = 6, Np = 54) increased after CES and showed better reliability in crossover than parallel design. The SBF increased after CES, and then declined until reaching a plateau 20 minutes postCES. SBF showed acceptable reliability both in crossover and parallel designs (Ncr = 3, Np = 13). Pain ratings to SES were reliable, but with large estimated sample sizes (Ncr = 634, Np = 11310) due to the minor pain amplification. Conclusions The reliability of 10 Hz CES was acceptable in inducing LTP-like effects in the assessments of superficial blood flow, heterotopic mechanical hyperalgesia, and dysesthesia in terms of sample sizes for future crossover study designs. PMID:27529175

  7. Sediment mobilization deposits from episodic subsurface fluid flow - A new tool to reveal long-term earthquake records?

    NASA Astrophysics Data System (ADS)

    Reusch, Anna; Moernaut, Jasper; Anselmetti, Flavio S.; Strasser, Michael

    2016-04-01

    Subsurface fluid flow can be affected by earthquakes: increased spring activity, mud volcano eruptions, groundwater fluctuations, changes in geyser frequency and other forms of altered subsurface fluid flow have been documented during, after, or even prior to earthquakes. Recently discovered giant pockmarks on the bottom of Lake Neuchâtel, Switzerland, are the lake-floor expression of subsurface fluid flow. They discharge karstic groundwater from the Jura Mountains and experience episodically increased subsurface fluid flow documented by subsurface sediment mobilization deposits at the levees of the pockmarks. In this study, we present the spatio-temporal distribution of event deposits from phases of sediment expulsion and their time correlative multiple mass-transport deposits. We report striking evidence for five events of concurrent multiple subsurface sediment deposits and multiple mass-transport deposits since Late Glacial times, for which we propose past earthquakes as trigger. Comparison of this new event catalogue with historic earthquakes and other independent paleoseismic records suggests that initiation of sediment expulsion requires a minimum macroseismic intensity of VII. Thus, our study presents for the first time sedimentary deposits resulting from increased subsurface fluid flow as new paleoseismic proxy. Comparable processes must also be relevant for other mountain front ranges and coastal mountain ranges, where groundwater flow triggers subsurface sediment mobilization and discharges into lacustrine and marine settings.

  8. Validated Metrics of Quick Flow Improve Assessments of Streamflow Generation Processes at the Long-Term Sleepers River Research Site

    NASA Astrophysics Data System (ADS)

    Sebestyen, S. D.; Shanley, J. B.

    2015-12-01

    There are multiple approaches to quantify quick flow components of streamflow. Physical hydrograph separations of quick flow using recession analysis (RA) are objective, reproducible, and easily calculated for long-duration streamflow records (years to decades). However, this approach has rarely been validated to have a physical basis for interpretation. In contrast, isotopic hydrograph separation (IHS) and end member mixing analysis using multiple solutes (EMMA) have been used to identify flow components and flowpath routing through catchment soils. Nonetheless, these two approaches are limited by data from limited and isolated periods (hours to weeks) during which more-intensive grab samples were analyzed. These limitations oftentimes make IHS and EMMA difficult to generalize beyond brief windows of time. At the Sleepers River Research Watershed (SRRW) in northern Vermont, USA, we have data from multiple snowmelt events over a two decade period and from multiple nested catchments to assess relationships among RA, IHS, and EMMA. Quick flow separations were highly correlated among the three techniques, which shows links among metrics of quick flow, water sources, and flow path routing in a small (41 ha), forested catchment (W-9) The similarity in responses validates a physical interpretation for a particular RA approach (the Ekhardt recursive RA filter). This validation provides a new tool to estimate new water inputs and flowpath routing for more and longer periods when chemical or isotopic tracers may not have been measured. At three other SRRW catchments, we found similar strong correlations among the three techniques. Consistent responses across four catchments provide evidence to support other research at the SRRW that shows that runoff generation mechanisms are similar despite differences in catchment sizes and land covers.

  9. Exploring the impacts of multiple tidal constituents and varying river flow on long-term, large-scale estuarine morphodynamics by means of a 1-D model

    NASA Astrophysics Data System (ADS)

    Guo, Leicheng; Wegen, Mick; Wang, Zheng Bing; Roelvink, Dano; He, Qing

    2016-05-01

    Tidal asymmetry is an important mechanism generating tidal residual sediment transport (TRST) in tidal environments. So far, it is known that a number of tidal interactions (e.g., M2-M4 and M2-O1-K1) can induce tidal asymmetry and associated TRST; however, their variability and morphodynamic impacts are insufficiently explored. Inspired by the river and tidal forcing conditions in the Yangtze River Estuary, we explore the morphodynamic development of a 560 km long estuary under the boundary forcing conditions of varyingly combined tidal constituents and river discharges using a schematized 1-D morphodynamic model for long-term (millennial) simulations. We then employ an analytical scheme which integrates sediment transport as a function of flow velocities to decompose the contribution of different tidal interactions on TRST and to explain how the river and tidal interactions control TRST and associated morphodynamics. Model results display varying equilibrium bed profiles. Analytical results suggest that (1) a series of tidal interactions creates multiple tidal asymmetries and associated TRST, (2) river flow modulates tidal asymmetry nonlinearly in space, and (3) more tidal constituents at the sea boundary persistently enhance the seaward TRST through river-tide interactions. It is the combined effects of multiple tidal asymmetries and river-tide interactions that determine the net TRST and consequent morphodynamic development. It thus suggests that tidal harmonics of significant amplitudes need to be considered properly as boundary conditions for long-term, large-scale morphodynamic modeling.

  10. A Serendipitous, Long-Term Infiltration Experiment: Water and Tritium Circulation Beneath the CAMBRIC Ditch at the Nevada Test Site

    SciTech Connect

    Maxwell, R M; Tompson, A B; Kollet, S J

    2008-11-20

    Underground nuclear weapons testing at the Nevada Test Site introduced numerous radionuclides that may be used to characterize subsurface hydrologic transport processes in arid climates. A sixteen year pumping experiment designed to examine radionuclide migration away from the CAMBRIC nuclear test, conducted in groundwater beneath Frenchman Flat in 1965, gave rise to an unintended second experiment involving radionuclide infiltration through the vadose zone, as induced by seepage of pumping effluents beneath an unlined discharge trench. The combined experiments have been reanalyzed using a detailed, three-dimensional numerical model of transient, variably saturated flow and mass transport, tailored specifically for large scale and efficient calculations. Simulations have been used to estimate radionuclide travel and residence times in various parts of the system for comparison with observations in wells. Model predictions of mass transport were able to clearly demonstrate radionuclide recycling behavior between the ditch and pumping well previously suggested by isotopic age dating information; match travel time estimates for radionuclides moving between the ditch, the water table, and monitoring wells; and provide more realistic ways in which to interpret the pumping well elution curves. Collectively, the results illustrate the utility of integrating detailed numerical modeling with diverse observational data in developing accurate interpretations and forecasts of contaminant migration processes.

  11. A serendipitous, long-term infiltration experiment: water and tritium circulation beneath the CAMBRIC trench at the Nevada Test Site.

    PubMed

    Maxwell, Reed M; Tompson, Andrew F B; Kollet, Stefan

    2009-08-11

    Underground nuclear weapons testing at the Nevada Test Site introduced numerous radionuclides that may be used subsequently to characterize subsurface hydrologic transport processes in arid climates. In 1965, a unique, 16-year pumping experiment designed to examine radionuclide migration away from the CAMBRIC nuclear test, conducted in the saturated zone beneath Frenchman Flat, Nevada, USA, gave rise to an unintended second experiment involving radionuclide infiltration through the vadose zone, as induced by seepage of pumping effluents beneath an unlined discharge trench. The combined experiments have been reanalyzed using a detailed, three-dimensional numerical model of transient, variably saturated flow and mass transport in a heterogeneous subsurface, tailored specifically for large-scale and efficient calculations. Simulations have been used to estimate tritium travel and residence times in various parts of the system for comparison with observations in wells. Model predictions of mass transport were able to clearly demonstrate radionuclide recycling behavior between the trench and pumping well previously suggested by isotopic age dating information; match travel time estimates for radionuclides moving between the trench, the water table, and monitoring and pumping wells; and provide more realistic ways in which to interpret the pumping well elution curves. Collectively, the results illustrate the utility of integrating detailed numerical modeling with diverse observational data in developing more accurate interpretations of contaminant migration processes. PMID:19501933

  12. A serendipitous, long-term infiltration experiment: Water and tritium circulation beneath the CAMBRIC trench at the Nevada Test Site

    NASA Astrophysics Data System (ADS)

    Maxwell, Reed M.; Tompson, Andrew F. B.; Kollet, Stefan

    2009-08-01

    Underground nuclear weapons testing at the Nevada Test Site introduced numerous radionuclides that may be used subsequently to characterize subsurface hydrologic transport processes in arid climates. In 1965, a unique, 16-year pumping experiment designed to examine radionuclide migration away from the CAMBRIC nuclear test, conducted in the saturated zone beneath Frenchman Flat, Nevada, USA, gave rise to an unintended second experiment involving radionuclide infiltration through the vadose zone, as induced by seepage of pumping effluents beneath an unlined discharge trench. The combined experiments have been reanalyzed using a detailed, three-dimensional numerical model of transient, variably saturated flow and mass transport in a heterogeneous subsurface, tailored specifically for large-scale and efficient calculations. Simulations have been used to estimate tritium travel and residence times in various parts of the system for comparison with observations in wells. Model predictions of mass transport were able to clearly demonstrate radionuclide recycling behavior between the trench and pumping well previously suggested by isotopic age dating information; match travel time estimates for radionuclides moving between the trench, the water table, and monitoring and pumping wells; and provide more realistic ways in which to interpret the pumping well elution curves. Collectively, the results illustrate the utility of integrating detailed numerical modeling with diverse observational data in developing more accurate interpretations of contaminant migration processes.

  13. Drought-induced changes in flow regimes lead to long-term losses in mussel-provided ecosystem services.

    PubMed

    Vaughn, Caryn C; Atkinson, Carla L; Julian, Jason P

    2015-03-01

    Extreme hydro-meteorological events such as droughts are becoming more frequent, intense, and persistent. This is particularly true in the south central USA, where rapidly growing urban areas are running out of water and human-engineered water storage and management are leading to broad-scale changes in flow regimes. The Kiamichi River in southeastern Oklahoma, USA, has high fish and freshwater mussel biodiversity. However, water from this rural river is desired by multiple urban areas and other entities. Freshwater mussels are large, long-lived filter feeders that provide important ecosystem services. We ask how observed changes in mussel biomass and community composition resulting from drought-induced changes in flow regimes might lead to changes in river ecosystem services. We sampled mussel communities in this river over a 20-year period that included two severe droughts. We then used laboratory-derived physiological rates and river-wide estimates of species-specific mussel biomass to estimate three aggregate ecosystem services provided by mussels over this time period: biofiltration, nutrient recycling (nitrogen and phosphorus), and nutrient storage (nitrogen, phosphorus, and carbon). Mussel populations declined over 60%, and declines were directly linked to drought-induced changes in flow regimes. All ecosystem services declined over time and mirrored biomass losses. Mussel declines were exacerbated by human water management, which has increased the magnitude and frequency of hydrologic drought in downstream reaches of the river. Freshwater mussels are globally imperiled and declining around the world. Summed across multiple streams and rivers, mussel losses similar to those we document here could have considerable consequences for downstream water quality although lost biofiltration and nutrient retention. While we cannot control the frequency and severity of climatological droughts, water releases from reservoirs could be used to augment stream flows and

  14. Drought-induced changes in flow regimes lead to long-term losses in mussel-provided ecosystem services

    PubMed Central

    Vaughn, Caryn C; Atkinson, Carla L; Julian, Jason P

    2015-01-01

    Extreme hydro-meteorological events such as droughts are becoming more frequent, intense, and persistent. This is particularly true in the south central USA, where rapidly growing urban areas are running out of water and human-engineered water storage and management are leading to broad-scale changes in flow regimes. The Kiamichi River in southeastern Oklahoma, USA, has high fish and freshwater mussel biodiversity. However, water from this rural river is desired by multiple urban areas and other entities. Freshwater mussels are large, long-lived filter feeders that provide important ecosystem services. We ask how observed changes in mussel biomass and community composition resulting from drought-induced changes in flow regimes might lead to changes in river ecosystem services. We sampled mussel communities in this river over a 20-year period that included two severe droughts. We then used laboratory-derived physiological rates and river-wide estimates of species-specific mussel biomass to estimate three aggregate ecosystem services provided by mussels over this time period: biofiltration, nutrient recycling (nitrogen and phosphorus), and nutrient storage (nitrogen, phosphorus, and carbon). Mussel populations declined over 60%, and declines were directly linked to drought-induced changes in flow regimes. All ecosystem services declined over time and mirrored biomass losses. Mussel declines were exacerbated by human water management, which has increased the magnitude and frequency of hydrologic drought in downstream reaches of the river. Freshwater mussels are globally imperiled and declining around the world. Summed across multiple streams and rivers, mussel losses similar to those we document here could have considerable consequences for downstream water quality although lost biofiltration and nutrient retention. While we cannot control the frequency and severity of climatological droughts, water releases from reservoirs could be used to augment stream flows and

  15. Vascular flow reserve as a link between long-term blood pressure level and physical performance capacity in mammals.

    PubMed

    Poulsen, Christian B; Damkjær, Mads; Hald, Bjørn O; Wang, Tobias; Holstein-Rathlou, Niels-Henrik; Jacobsen, Jens Christian B

    2016-06-01

    Mean arterial pressure (MAP) is surprisingly similar across different species of mammals, and it is, in general, not known which factors determine the arterial pressure level. Mammals often have a pronounced capacity for sustained physical performance. This capacity depends on the vasculature having a flow reserve that comes into play as tissue metabolism increases. We hypothesize that microvascular properties allowing for a large vascular flow reserve is linked to the level of the arterial pressure.To study the interaction between network properties and network inlet pressure, we developed a generic and parsimonious computational model of a bifurcating microvascular network where diameter and growth of each vessel evolves in response to changes in biomechanical stresses. During a simulation, the network develops well-defined arterial and venous vessel characteristics. A change in endothelial function producing a high precapillary resistance and thus a high vascular flow reserve is associated with an increase in network inlet pressure. Assuming that network properties are independent of body mass, and that inlet pressure of the microvascular network is a proxy for arterial pressure, the study provides a conceptual explanation of why high performing animals tend to have a high MAP. PMID:27255360

  16. Bivalent response to long-term storage in liquid-preserved boar semen: a flow cytometric analysis.

    PubMed

    Henning, Heiko; Petrunkina, Anna M; Harrison, Robin A P; Waberski, Dagmar

    2012-07-01

    The fertility of liquid-preserved boar semen declines during storage at 17°C, insemination trials even indicating early losses in fertilizing ability within the first 24-48 h of storage. Standard semen parameters barely reflect these changes in semen quality, and new approaches for assessment of functional changes in stored spermatozoa are needed. Capacitation, the essential prefertilization step for spermatozoa in the female genital tract, is specifically induced in vitro by bicarbonate. Therefore, we have investigated changes in responsiveness of boar spermatozoa to bicarbonate during storage. Ejaculates of 14 boars were diluted in Beltsville thawing solution, cooled to 17°C and stored for 12, 24, 72, 120, and 168 h before investigation. At each time, basic semen quality was characterized by sperm motility and viability. Subsequently, washed subsamples were incubated in variants of an in vitro fertilization (IVF) medium and assessed for kinetic changes of viability (plasma membrane integrity) and intracellular calcium concentration using flow cytometry in combination with propidium iodide and Fluo-3. By this means, it was possible to determine specific effects of bicarbonate and calcium on sperm subpopulations over incubation time. During storage, standard semen parameters remained on a high level. However, flow cytometric analysis of sperm responses to capacitating and control media revealed two opposing effects of storage. There was a loss of response to bicarbonate in part of the live sperm population but an increasing degree of instability in the rest. Assessment of response to capacitating media by flow cytometry appears a markedly more sensitive way of monitoring sperm functionality during storage than the standard semen parameters of motility and viability. PMID:22573481

  17. New therapy, new challenges: The effects of long-term continuous flow left ventricular assist device on inflammation.

    PubMed

    Grosman-Rimon, Liza; Billia, Filio; Fuks, Avi; Jacobs, Ira; A McDonald, Michael; Cherney, David Z; Rao, Vivek

    2016-07-15

    Surgically implanted continuous flow left ventricular assist devices (CF-LVADs) are currently used in patients with end-stage heart failure (HF). However, CF-LVAD therapy introduces a new set of complications and adverse events in these patients. Major adverse events with the CF-LVAD include right heart failure, vascular dysfunction, stroke, hepatic failure, and multi-organ failure, complications that may have inflammation as a common etiology. Our aim was to review the current evidence showing a relationship between these adverse events and elevated levels of inflammatory biomarkers in CF-LVAD recipients. PMID:27131263

  18. The role of episodic fire-related debris flows on long-term (103-104) sediment yields in the Middle Fork Salmon River Watershed, in central Idaho

    NASA Astrophysics Data System (ADS)

    Riley, K. E.; Pierce, J. L.; Hopkins, A.

    2010-12-01

    Episodic fire-related debris flows contribute large amounts of sediment and large woody debris to streams. This study evaluates fire-related sedimentation from small steep tributaries of the Middle Fork Salmon River (MFSR) in central Idaho to evaluate the timing, frequency, and magnitude of episodic fire-related sedimentation on long-term (10 3-10 4) sediment yields. The MFSR lies within the Northern Rocky Mountains and encompasses a range of ecosystems including high elevation (~3,000 -1,700 m) subalpine pine and spruce forests, mid-elevation (2650 - 1130 m) montane Douglas-fir and ponderosa pine-dominated forests and low elevation (~ 1,800 - 900 m) sagebrush steppe. Recent debris flow events in tributaries of the MFSR appear to primarily result from increased surface runoff, rilling, and progressive sediment bulking following high severity fires. This study estimates: 1) the volume of sediment delivered by four recent (1997-2008) fire-related debris flow events using real time kinematic GPS surveys, and 2) the timing of Holocene fire-related debris flow events determined by 14C dating charcoal fragments preserved in buried burned soils and within fire-related deposits. Our measured volumes of the four recent debris flow events are compared to two empirically derived volume estimates based on remotely sensed spatial data (burn severity and slope), measured geometric data (longitudinal profile, cross sectional area, flow banking angle), and precipitation records. Preliminary stratigraphic profiles in incised alluvial fans suggest that a large percentage of alluvial fan thickness is composed of fire-related deposits suggesting fire-related hillslope erosion is a major process delivering sediment to alluvial fans and to the MFSR. Fire-related deposits from upper basins compose ~71% of total alluvial fan thickness, while fire-related deposits from lower basins make up 36% of alluvial fan thickness. However, lower basins are less densely vegetated with small diameter

  19. Long-term effects of triethylenemelamine exposure on mouse testis cells and sperm chromatin structure assayed by flow cytometry

    SciTech Connect

    Evenson, D.P.; Baer, R.K.; Jost, L.K. )

    1989-01-01

    The toxic and potentially mutagenic actions of triethylenemelamine (TEM) on mouse body and testis weights, testicular cell kinetics, sperm production, sperm head morphology, and sperm chromatin structure were assessed in two experiments. The first experiment examined effects of four dose levels of TEM, assayed 1, 4, or 10 wk after toxic exposure. In the second study, effects from five dosage levels were measured at 1, 4, and 10 wk, and the highest dosage level was evaluated over 44 wk. TEM produced an expected dose related loss of spermatogenic activity and subsequent recovery as determined by dual-parameter (DNA, RNA) flow cytometry (FCM) measurements of testicular cells. Both testicular weights and caudal sperm reserves remained generally below controls after 44 wk recovery following exposure to the highest dosage. Chromatin structure alterations, defined as increased susceptibility to DNA denaturation in situ, and sperm head morphology were highly correlated with dose and with each other. Sperm head morphology and sperm chromatic structure remained abnormal at 44 wk for the 1.0 mg/kg TEM dosage, suggesting that the abnormalities, present long after the initial toxic response, may be a result of mutation. This study demonstrates that flow cytometry provides a unique, rapid, and efficient means to measure effects of reproductive toxins and potential mutagens.

  20. Long term operation of continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    PubMed

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-09-01

    In this study, a continuous-flow system with enhanced biological phosphorus removal (EBPR) granules was operated at different COD concentrations (200, 300 and 400mgL(-)(1)) to investigate the effect of COD loading on this system. The results showed that when the COD concentration in influent was increased to 400mgL(-)(1), the anaerobic COD removal efficiency and total phosphorus removal efficiency reduced obviously and the settling ability of granules deteriorated due to the proliferation of filamentous bacteria. Moreover, high COD loading inhibited the EPS secretion and destroyed the stability of granules. Results of high-through pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading. The performance of system, settling ability of granules and proportion of PAOs gradually recovered to the initial level after the COD concentration was reduced to 200mgL(-)(1) on day 81. PMID:27295254

  1. Estimation of long-term Ca(2+) loss through outlet flow from an agricultural watershed and the influencing factors.

    PubMed

    Zhang, Wenzhao; Yin, Chunmei; Chen, Chunlan; Chen, Anlei; Xie, Xiaoli; Fu, Xingan; Hou, Haijun; Wei, Wenxue

    2016-06-01

    Soil Ca(2+) loss from agricultural lands through surface runoff can accelerate soil acidification and render soil degradation, but the characteristics of Ca(2+) loss and influencing factors in watershed scale are unclear. This study was carried out in a watershed with various land uses in a subtropical region of China. The outlet flow was automatically monitored every 5 min all year round, and the water samples were collected twice a year from 2001 to 2011. The concentrations of Ca(2+), Mg(2+), K(+), total nitrogen (TN), and total phosphorus (TP) of water samples were measured. The dynamic losses of the nutrients through the outlet flow were estimated, and the relationships between the nutrient losses and rainfall intensity as well as antecedent soil moisture were investigated. The results showed that great variations of nutrient concentrations and losses appeared during the investigation period. The average concentrations of Ca(2+), Mg(2+), K(+), TN, and TP were 0.43, 0.08, 0.10, 0.19, and 0.003 mmol L(-1), respectively. The average Ca(2+) loss reached 1493.79 mol ha(-1) year(-1) and was several times higher than for Mg(2+), K(+), and TN, about 140 times higher than for TP. Rainfall intensity had remarkable effects on Ca(2+) concentration (P < 0.01) and loss (P < 0.05) when it reached rainstorm level (50 mm day(-1)), while a quadratic relationship was observed between antecedent soil moisture and Ca(2+) concentration only when rainfall intensity was less than 50 mm day(-1). In a word, much greater amounts of Ca(2+) were lost from the watershed, and this may be one important contributor to the increasing acidification of acidic soils in subtropical regions. PMID:26898929

  2. Long-term effects of triethylenemelamine exposure on mouse testis cells and sperm chromatin structure assayed by flow cytometry.

    PubMed

    Evenson, D P; Baer, R K; Jost, L K

    1989-01-01

    The toxic and potentially mutagenic actions of triethylenemelamine (TEM) on mouse body and testis weights, testicular cell kinetics, sperm production, sperm head morphology, and sperm chromatin structure were assessed in two experiments. The first experiment examined effects of four dose levels of TEM, assayed 1, 4, and 10 wk after toxic exposure. In the second study, effects from five dosage levels were measured at 1, 4, and 10 wk, and the highest dosage level was evaluated over 44 wk. TEM produced an expected dose related loss of spermatogenic activity and subsequent recovery as determined by dual-parameter (DNA, RNA) flow cytometry (FCM) measurements of testicular cells. Both testicular weights and caudal sperm reserves remained generally below controls after 44 wk recovery following exposure to the highest (1.0 mg/kg daily x 5) dosage. Chromatin structure alterations, defined as increased susceptibility to DNA denaturation in situ, and sperm head morphology were highly correlated (.87-.93, P less than .001) with dose and with each other. Data obtained from the sperm chromatin structure essay (SCSA) on fresh sperm was highly correlated with measurements of aliquots of the same sample collected over 44 wk, frozen, and then measured on the same day. Sperm head morphology and sperm chromatin structure remained abnormal at 44 wk for the 1.0 mg/kg TEM dosage, suggesting that the abnormalities, present long after the initial toxic response, may be a result of mutation. This study demonstrates that flow cytometry provides a unique, rapid, and efficient means to measure effects of reproductive toxins and potential mutagens. PMID:2767059

  3. [Effects of Long-term Implementation of the Flow-Sediment Regulation Scheme on Grain and Clay Compositions of Inshore Sediments in the Yellow River Estuary].

    PubMed

    Wang, Miao-miao; Sun, Zhi-gao; Lu, Xiao-ning; Wang, Wei; Wang, Chuan-yuan

    2015-04-01

    Based on the laser particle size and X-ray diffraction (XRD) analysis, 28 sediment samples collected from the inshore region of the Yellow River estuary in October 2013 were determined to discuss the influence of long-term implementation of the flow-sediment regulation scheme (FSRS, initiated in 2002) on the distributions of grain size and clay components (smectite, illite, kaolinite and chlorite) in sediments. Results showed that, after the FSRS was implemented for more than 10 years, although the proportion of sand in inshore sediments of the Yellow River estuary was higher (average value, 23.5%) than those in sediments of the Bohai Sea and the Yellow River, silt was predominated (average value, 59.1%) and clay components were relatively low (average value, 17.4%). The clay components in sediments of the inshore region in the Yellow River estuary were close with those in the Yellow River. The situation was greatly changed due to the implementation of FSRS since 2002, and the clay components were in the order of illite > smectite > chlorite > kaolinite. This study also indicated that, compared to large-scale investigation in Bohai Sea, the local study on the inshore region of the Yellow River estuary was more favorable for revealing the effects of long-term implementation of the FSRS on sedimentation environment of the Yellow River estuary. PMID:26164898

  4. Using the Sonoran Desert test site to monitor the long-term radiometric stability of the Landsat TM/ETM+ and Terra MODIS sensors

    USGS Publications Warehouse

    Angal, A.; Xiong, X.; Choi, T.; Chander, G.; Wu, A.

    2009-01-01

    Pseudo-invariant ground targets have been extensively used to monitor the long-term radiometric calibration stability of remote sensing instruments. The NASA MODIS Characterization Support Team (MCST), in collaboration with members from the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center, has previously demonstrated the use of pseudo-invariant ground sites for the long-term stability monitoring of Terra MODIS and Landsat 7 ETM+ sensors. This paper focuses on the results derived from observations made over the Sonoran Desert. Additionally, Landsat 5 TM data over the Sonoran Desert site were used to evaluate the temporal stability of this site. Top-ofatmosphere (TOA) reflectances were computed for the closely matched TM, ETM+, and MODIS spectral bands over selected regions of interest. The impacts due to different viewing geometries, or the effect of test site Bi-directional Reflectance Distribution Function (BRDF), are also presented. ?? 2009 SPIE.

  5. Long-Term Results from Evaluation of Advanced New Construction Packages in Test Homes: Lake Elsinore, Californi

    SciTech Connect

    Stecher, D.; Brozyna, K.

    2013-08-01

    This report presents the long-term evaluation results from a hot-dry climate project that examines the room-to-room temperature conditions that exist in a high performance envelope, the performance of a simplified air distribution system, and a comparison of modeled energy performance with measured energy use. The project, a prototype house built by K. Hovnanian Homes’ Ontario Group, is located in Lake Elsinore, Riverside County, California, and achieves a 50% level of whole house source energy savings with respect to the Building America (BA) Benchmark Definition 2009 (Hendron and Engebrecht 2010). Temperature measurements in three rooms indicate that the temperature difference between the measured locations and the thermostat were within recommendations 90.3% of the time in heating mode and 99.3% of the time in cooling mode. The air distribution system is operating efficiently with average delivered temperatures adequate to facilitate proper heating and cooling and only minor average temperature differences observed between the system’s plenum and farthest register. Monitored energy use results for the house indicate that it is using less energy than predicted from modeling. A breakdown of energy use according to end use determined little agreement between comparable values.

  6. Study Design to Test the Hypothesis That Long-Term Space Travel Harms the Human and Animal Immune Systems

    NASA Technical Reports Server (NTRS)

    Shearer, William T.; Lugg, Desmond J.; Ochs, H. D.; Pierson, Duane L.; Reuben, James M.; Rosenblatt, Howard M.; Sams, Clarence; Smith, C. Wayne; Smith, E. Obrian; Smolen, James E.

    1999-01-01

    The potential threat of immunosuppression and abnormal inflammatory responses in long-term space travel, leading to unusual predilection for opportunistic infections, malignancy, and death, is of ma or concern to the National Aeronautics and Space Administration (NASA) Program. This application has been devised to seek answers to questions of altered immunity in space travel raised by previous investigations spanning 30-plus years. We propose to do this with the help of knowledge gained by the discovery of the molecular basis of many primary and secondary immunodeficiency diseases and by application of molecular and genetic technology not previously available. Two areas of immunity that previously received little attention in space travel research will be emphasized: specific antibody responses and non-specific inflammation and adhesion. Both of these areas of research will not only add to the growing body of information on the potential effects of space travel on the immune system, but be able to delineate any functional alterations in systems important for antigen presentation, specific immune memory, and cell:cell and cell:endothelium interactions. By more precisely defining molecular dysfunction of components of the immune system, it is hoped that targeted methods of prevention of immune damage in space could be devised.

  7. Long-Term Results from Evaluation of Advanced New Construction Packages in Test Homes: Lake Elsinore, California

    SciTech Connect

    Stecher, D.; Brozyna, K.

    2013-08-01

    This report presents the long-term evaluation results from a hot-dry climate project that examines the room-to-room temperature conditions that exist in a high performance envelope, the performance of a simplified air distribution system, and a comparison of modeled energy performance with measured energy use. The project, a prototype house built by K. Hovnanian Homes' Ontario Group, is located in Lake Elsinore, Riverside County, California, and achieves a 50% level of whole house source energy savings with respect to the Building America (BA) Benchmark Definition 2009 (Hendron and Engebrecht 2010). Temperature measurements in three rooms indicate that the temperature difference between the measured locations and the thermostat were within recommendations 90.3% of the time in heating mode and 99.3% of the time in cooling mode. The air distribution system is operating efficiently with average delivered temperatures adequate to facilitate proper heating and cooling and only minor average temperature differences observed between the system's plenum and farthest register. Monitored energy use results for the house indicate that it is using less energy than predicted from modeling. A breakdown of energy use according to end use determined little agreement between comparable values.

  8. New perspectives and advanced approaches on effectively processing Big InSAR data: from long term ERS archives to new Sentinel-1 massive data flow

    NASA Astrophysics Data System (ADS)

    Casu, Francesco; De Luca, Claudio; Elefante, Stefano; Lanari, Riccardo; Manunta, Michele; Zinno, Ivana

    2015-04-01

    Advanced differential Synthetic Aperture Radar (SAR) Interferometry (InSAR) usually identifies a set of algorithms, tools and methodologies for the generation of Earth's surface deformation maps and time series computed from a sequence of multi-temporal differential SAR interferograms. Such techniques found their success on the large availability of SAR data archives acquired over time by several satellite systems. Indeed, the current radar Earth Observation (EO) scenario takes advantage of the widely diffused long-term C-band ESA (e.g. ERS-1, ERS-2 and ENVISAT) and Canadian (RADARSAT-1/2) SAR data archives, which have been acquired during the last 20 years, as well as of data sequences provided by the X-band generation SAR sensors, such as the COSMO-SkyMed (CSK) and TerraSAR-X (TSX) constellations. Moreover, a massive and ever increasing data flow will be further supplied by the recently launched (April 2014) Copernicus (European Union) SENTINEL-1A SAR satellite, which will also be paired during 2016 with the SENTINEL-1B twin system that will allow halving the constellation revisit time (from 12 to 6 days). In this context, the massive exploitation of these Big InSAR Data archives for the generation of advanced products will open new research perspectives to understand Earth's surface deformation dynamics at global scale. However, to reach this ambitious goal, Big InSAR Data has to be effectively exploited to generate accurate advanced products in short time frames. Therefore the need of new InSAR processing approaches, efficient algorithms and high performance computing facilities represents the basis for fully benefiting from such a Big Data. In this work we first present the recently proposed Parallel Small BAseline Subset (P-SBAS) InSAR algorithm that has been designed to process big volumes of InSAR data in short times and unsupervised manner by exploiting High Performance Computing (HPC) facilities. Then, we show how the P-SBAS approach is well suitable for

  9. CAREER: Hydrothermal vent flow and temperature fluctuations: exploring long-term variability through an integrated research and education program

    NASA Astrophysics Data System (ADS)

    Di Iorio, D.

    2011-12-01

    An acoustic scintillation system was built in partnership with ASL Environmental Sciences (Sidney BC Canada), which provided a unique opportunity for two engineering undergraduate students to live and work abroad. The acoustic instrumentation was tested in coastal waters and then deployed to study deep-sea hydrothermal plume dynamics. Undergraduate students were involved in the deployment of instrumentation and the development of processing software to give vertical velocities and temperature fluctuations from a vigorous hydrothermal vent. A graduate student thesis has yielded insights into the vertical and azimuthal dependence of entrainment and into plume bending and rise height. Teachers and Ocean Science Bowl students also participated in research cruises describing physical oceanography of estuaries, coastal waters, and deep-sea hydrothermal vents and participated in data collection, processing and analysis. Teachers used the knowledge they gained to develop creative educational curricula at their schools, to present their experiences at national conferences and to publish an article in the National Science Teachers Association - The Science Journal. One of the teachers was recently recognized with the Presidential Award for Excellence in Mathematics and Science Teaching. Working with the ocean bowl team at Oconee County High School has led to top ten placements in the national championships in 2005 (fourth place) and 2006 (sixth place). In order to increase quantitative methods in an undergraduate class, students acquire data from an ocean observatory and analyze the data for specific quantities of interest. One such project led to the calculation of the upper ocean heat content for the Greenland Sea using 7 years of Argo profiles, which showed a 0.04oC/year trend. These results were then published in JGR.

  10. Evaluation of precipitates used in strainer head loss testing : Part III. Long-term aluminum hydroxide precipitation tests in borated water.

    SciTech Connect

    Bahn, C. B.; Kasza, K. E.; Shack, W. J.; Natesan, K.; Klein, P.

    2011-05-01

    Long-term aluminum (Al) hydroxide precipitation tests were conducted in slightly alkaline solutions containing 2500 ppm boron. The solution temperature was cycled to obtain a temperature history more representative of emergency core cooling system temperatures after a loss-of-coolant accident. The observed Al precipitation boundary was close to predicted results for amorphous precipitates, which are higher than the solubility expected for crystalline forms. Bench-scale and loop head loss test results under various conditions were successfully combined into single map in a temperature - 'pH + p[Al]{sub T}' domain, which yielded two bounding lines for Al hydroxide solubility in borated alkaline water that depend on whether or not loop head loss tests with Al alloy coupons are included. Precipitates were observed to form either as fine, cloudy suspensions, which showed very little tendency to settle, or as flocculated precipitates. The flocculation tendency of the precipitates can be qualitatively explained by a colloid stability theory or a phase diagram for protein solutions.

  11. The interactive effects of a gradual temperature decrease and long-term food deprivation on cardiac and hepatic blood flows in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Petersen, L H; Dzialowski, E; Huggett, D B

    2011-11-01

    The aim of the present study was to determine the extent to which the fish liver is perfused with blood. Transonic® flow probes were therefore implanted around the ventral aorta and hepatic vein(s) to record baseline blood flows in rainbow trout (Oncorhynchus mykiss) previously held under two different feeding regimes (food-deprived or fed to satiation, 8-12 weeks). Fish from both groups were exposed to a gradual temperature decrease (12°C to 5°C) and physical disturbance. Cardiac output (Q), stroke volume (Sv) and hepatic venous blood flow (HVBF) were significantly reduced in food-deprived trout at 12°C. Heart rate was not significantly affected by nutritional status, but was significantly reduced when temperature was decreased to 5°C. Physically disturbing each fish at 12°C and 5°C showed that the performance capacity of the heart was not affected by food deprivation as the capacity to increase Q and Sv was not reduced in the food-deprived group. Overall this study showed that food deprivation in rainbow trout reduced cardiac and hepatic blood flows. However, long-term food deprivation did not affect the capacity of the heart to acutely increase performance. PMID:21601001

  12. Rapid stress-testing vs. long-term aging: a case study of 980-nm emitting single-spatial mode lasers

    NASA Astrophysics Data System (ADS)

    Tomm, Jens W.; Hempel, Martin; Venables, David; Rossin, Victor; Zucker, Erik; Elsaesser, Thomas

    2016-03-01

    The degradation behaviors of 980-nm emitting nominally identical single-spatial mode lasers are studied during continuous wave long-term operation and during single-pulse stress tests. Both tests activate internal catastrophic optical damage as sudden degradation mechanism limiting the device lifetime. In case of high power stress-testing, the mechanism that initializes this effect is a spatial widening of the optical mode, resulting in increased absorption outside the waveguide. A similar disturbance to the optical mode is caused by defects that are generated during long-term operation. Thus two very different aging regimes eventually result in the same degradation scenario. We find that single-pulse stress-testing allows for activation of several degradation mechanisms in a device one after the other. Moreover, it becomes possible to distinguish between effects induced by gradual degradation and such that are independent on operation time. Thus stress-testing is considered a complementary tool, which might pave the way towards more economic device testing.

  13. The Role of Test Expectancy in the Build-Up of Proactive Interference in Long-Term Memory

    ERIC Educational Resources Information Center

    Weinstein, Yana; Gilmore, Adrian W.; Szpunar, Karl K.; McDermott, Kathleen B.

    2014-01-01

    We examined the hypothesis that interpolated testing in a multiple list paradigm protects against proactive interference by sustaining test expectancy during encoding. In both experiments, recall on the last of 5 word lists was compared between 4 conditions: a tested group who had taken tests on all previous lists, an untested group who had not…

  14. Interlaboratory Evaluation of Hyalella Azteca and Chironomus Tentans Short-term and Long-term Sediment Toxicity Tests

    EPA Science Inventory

    This paper presents the results of interlaboratory toxicity tests on sediment toxicity methods for use in routine testing and this data has been presented in an EPA report and this is a summary of that data.

  15. Test Methodology Development for Experimental Structural Assessment of ASC Planar Spring Material for Long-Term Durability

    NASA Technical Reports Server (NTRS)

    Yun, Gunjin; Abdullah, A. B. M.; Binienda, Wieslaw; Krause, David L.; Kalluri, Sreeramesh

    2014-01-01

    A vibration-based testing methodology has been developed that will assess fatigue behavior of the metallic material of construction for the Advanced Stirling Convertor displacer (planar) spring component. To minimize the testing duration, the test setup is designed for base-excitation of a multiplespecimen arrangement, driven in a high-frequency resonant mode; this allows completion of fatigue testing in an accelerated period. A high performance electro-dynamic exciter (shaker) is used to generate harmonic oscillation of cantilever beam specimens, which are clasped on the shaker armature with specially-designed clamp fixtures. The shaker operates in closed-loop control with dynamic specimen response feedback provided by a scanning laser vibrometer. A test coordinator function synchronizes the shaker controller and the laser vibrometer to complete the closed-loop scheme. The test coordinator also monitors structural health of the test specimens throughout the test period, recognizing any change in specimen dynamic behavior. As this may be due to fatigue crack initiation, the test coordinator terminates test progression and then acquires test data in an orderly manner. Design of the specimen and fixture geometry was completed by finite element analysis such that peak stress does not occur at the clamping fixture attachment points. Experimental stress evaluation was conducted to verify the specimen stress predictions. A successful application of the experimental methodology was demonstrated by validation tests with carbon steel specimens subjected to fully-reversed bending stress; high-cycle fatigue failures were induced in such specimens using higher-than-prototypical stresses

  16. Scheduling viability tests for seeds in long-term storage based on a Bayesian Multi-Level Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genebank managers conduct viability tests on stored seeds so they can replace lots that have viability near a critical threshold, such as 50 or 85% germination. Currently, these tests are typically scheduled at uniform intervals; testing every 5 years is common. A manager needs to balance the cost...

  17. [The Brumory test, an incidental long-term memory task designed for foreign, non-French-speaking people with low educational level].

    PubMed

    Vanderaspoilden, V; Nury, D; Frisque, J; Peigneux, P

    2015-12-01

    Cognitive assessment among foreign patients is a growing need for several reasons: foreign patients have a different culture, they have an insufficient command of the language of the consulting center, and the available cognitive tools are largely unsuitable. For these reasons, we developed a non-verbal test of long-term memory called the Brumory test. This test is based on incident encoding of 48 colored images followed by retrieval by recognition. We compared the performance of indigenous participants with that of immigrant participants (mainly from Morocco). Immigrant participants did not speak French properly and had a low educational level. The results indicate no significant difference in memory performance between the two groups of participants. Moreover, the instructions were easily understood by immigrant participants, despite the fact they do not master French. We conclude that the Brumory test is an appropriate test to assess memory among foreign non-French-speaking patients people with low educational level. PMID:26584740

  18. Effect of long-term exposure of 2.4 GHz radiofrequency radiation emitted from Wi-Fi equipment on testes functions.

    PubMed

    Dasdag, Suleyman; Taş, Muzaffer; Akdag, Mehmet Zulkuf; Yegin, Korkut

    2015-03-01

    The aim of this study was to investigate long-term effects of radiofrequency radiation (RFR) emitted from a Wireless Fidelity (Wi-Fi) system on testes. The study was carried out on 16 Wistar Albino adult male rats by dividing them into two groups such as sham (n: 8) and exposure (n: 8). Rats in the exposure group were exposed to 2.4 GHz RFR radiation for 24 h/d during 12 months (1 year). The same procedure was applied to the rats in the sham control group except the Wi-Fi system was turned off. Immediately after the last exposure, rats were sacrificed and reproductive organs were removed. Motility (%), concentration (×10(6)/mL), tail defects (%), head defects (%) and total morphologic defects (%) of sperms and weight of testes (g), left epididymis (g), prostate (g), seminal vesicles (g) were determined. Seminiferous tubules diameter (μm) and tunica albuginea thickness (μm) were also measured. However, the results were evaluated by using Johnsen's score. Head defects increased in the exposure group (p < 0.05) while weight of the epididymis and seminal vesicles, seminiferous tubules diameter and tunica albuginea thickness were decreased in the exposure group (p < 0.01, p < 0.001, p < 0.0001). However, other alterations of other parameters were not found significant (p > 0.05). In conclusion, we observed that long-term exposure of 2.4 GHz RF emitted from Wi-Fi (2420 μW/kg, 1 g average) affects some of the reproductive parameters of male rats. We suggest Wi-Fi users to avoid long-term exposure of RF emissions from Wi-Fi equipment. PMID:24460421

  19. Long Term Performance Retention Test Using High Power COTS NiCd and NiMH Cells

    NASA Technical Reports Server (NTRS)

    Hall, Dan; Darcy, Eric; Strangways, Brad; Nelson, Tim

    2003-01-01

    This slide presentation reviews the tests and results for performance retention of high powered commercial off the shelf (COTS) NiCd, and NiMH cells. Electromechanical actuators for space flight requires short duration high power batteries. The concern is that NiCd battery designs demonstrate an unfavorable power degradation after long periods of inactivity. Cycling can recover some of the decay, but this reduces the readiness that these batteries must have. Two 5-cell SubC stick test batteries ere chosen using NiCd and NiMH were tested and then the differences for charge maintenance were compared.

  20. Techniques for control of long-term reliability of complex integrated circuits. I - Reliability assurance by test vehicle qualification.

    NASA Technical Reports Server (NTRS)

    Van Vonno, N. W.

    1972-01-01

    Development of an alternate approach to the conventional methods of reliability assurance for large-scale integrated circuits. The product treated is a large-scale T squared L array designed for space applications. The concept used is that of qualification of product by evaluation of the basic processing used in fabricating the product, providing an insight into its potential reliability. Test vehicles are described which enable evaluation of device characteristics, surface condition, and various parameters of the two-level metallization system used. Evaluation of these test vehicles is performed on a lot qualification basis, with the lot consisting of one wafer. Assembled test vehicles are evaluated by high temperature stress at 300 C for short time durations. Stressing at these temperatures provides a rapid method of evaluation and permits a go/no go decision to be made on the wafer lot in a timely fashion.

  1. Final report: Long Term Test of a Gear-Type Pump for the Am/Cm Project

    SciTech Connect

    Duignan, M.R.

    1998-04-01

    At the request of the Immobilization Technology section, the Experimental Thermal Fluids group carried out a test to determine the operational characteristics of a gear-type pump. This pump was under consideration as a replacement for the air-lift melter feed pumping system of the Americium and Curium Project.

  2. Long term out-of-pile thermocouple tests in conditions representative for nuclear gas-cooled high temperature reactors

    SciTech Connect

    Laurie, M.; Fourrez, S.; Fuetterer, M. A.; Lapetite, J. M.

    2011-07-01

    During irradiation tests at high temperature, failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. To understand and remedy this problem, out-of-pile tests were performed with thermocouples in carburizing atmospheres which can be assumed to be at least locally representative for High Temperature Reactors. The objective was to screen those thermocouples which would consecutively be used under irradiation. Two such screening tests have been performed with a set of thermocouples embedded in graphite (mainly conventional Type N thermocouples and thermocouples with innovative sheaths) in a dedicated furnace with helium flushing. Performance indicators such as thermal drift, insulation and loop resistance were monitored and compared to those from conventional Type N thermocouples. Several parameters were investigated: niobium sleeves, bending, thickness, sheath composition, temperature as well as the chemical environment. After the tests, Scanning Electron Microscopy (SEM) examinations were performed to analyze possible local damage in wires and in the sheath. The present paper describes the two experiments, summarizes results and outlines further work, in particular to further analyze the findings and to select suitable thermocouples for qualification under irradiation. (authors)

  3. Extending periodic eddy covariance latent heat fluxes through tree sap-flow measurements to estimate long-term total evaporation in a peat swamp forest

    NASA Astrophysics Data System (ADS)

    Clulow, A. D.; Everson, C. S.; Mengistu, M. G.; Price, J. S.; Nickless, A.; Jewitt, G. P. W.

    2015-05-01

    A combination of measurement and modelling was used to find a pragmatic solution to estimate the annual total evaporation from the rare and indigenous Nkazana Peat Swamp Forest (PSF) on the east coast of Southern Africa to improve the water balance estimates within the area. Actual total evaporation (ETa) was measured during three window periods (between 7 and 9 days each) using an eddy covariance (EC) system on a telescopic mast above the forest canopy. Sap flows of an understory tree and an emergent tree were measured using a low-maintenance heat pulse velocity system for an entire hydrological year (October 2009 to September 2010). An empirical model was derived, describing the relationship between ETa from the Nkazana PSF and sap-flow measurements. These overlapped during two of the window periods (R2 = 0.92 and 0.90), providing hourly estimates of ETa from the Nkazana PSF for a year, totalling 1125 mm (while rainfall was 650 mm). In building the empirical model, it was found that to include the understory tree sap flow provided no benefit to the model performance. In addition, the relationship between the emergent tree sap flow with ETa between the two field campaigns was consistent and could be represented by a single empirical model (R2 = 0.90; RMSE = 0.08 mm h-1). During the window periods of EC measurement, no single meteorological variable was found to describe the Nkazana PSF ETa satisfactorily. However, in terms of evaporation models, the hourly FAO Penman-Monteith reference evaporation (ETo) best described ETa during the August 2009 (R2 = 0.75), November 2009 (R2 = 0.85) and March 2010 (R2 = 0.76) field campaigns, compared to the Priestley-Taylor potential evaporation (ETp) model (R2 = 0.54, 0.74 and 0.62 during the respective field campaigns). From the extended record of ETa (derived in this study from sap flow) and ETo, a monthly crop factor (Kc) was derived for the Nkazana PSF, providing a method of estimating long-term swamp forest water-use from

  4. Potential for Local Fertilization: A Benthocosm Test of Long-Term and Short-Term Effects of Mussel Excretion on the Plankton

    PubMed Central

    Granados, Monica; Duffy, Sean; Robert, Pauline; Péquin, Bérangère; Mohit, Vani; McKindsey, Christopher W.; Archambault, Philippe; Myrand, Bruno; Lovejoy, Connie; Tremblay, Réjean; Plourde, Stéphane; Fussmann, Gregor F.

    2016-01-01

    Mussel aquaculture has expanded worldwide and it is important to assess its impact on the water column and the planktonic food web to determine the sustainability of farming practices. Mussel farming may affect the planktonic food web indirectly by excreting bioavailable nutrients in the water column (a short-term effect) or by increasing nutrient effluxes from biodeposit-enriched sediments (a long-term effect). We tested both of these indirect effects in a lagoon by using plankton-enclosing benthocosms that were placed on the bottom of a shallow lagoon either inside of a mussel farm or at reference sites with no history of aquaculture. At each site, half of the benthocosms were enriched with seawater that had held mussels (excretion treatment), the other half received non-enriched seawater as a control treatment. We monitored nutrients ([PO43-] and [NH4+]), dissolved oxygen and plankton components (bacteria, the phytoplankton and the zooplankton) over 5 days. We found a significant relationship between long-term accumulation of mussel biodeposits in sediments, water-column nutrient concentrations and plankton growth. Effects of mussel excretion were not detected, too weak to be significant given the spatial and temporal variability observed in the lagoon. Effects of mussels on the water column are thus likely to be coupled to benthic processes in such semi-enclosed water bodies. PMID:27249793

  5. Potential for Local Fertilization: A Benthocosm Test of Long-Term and Short-Term Effects of Mussel Excretion on the Plankton.

    PubMed

    Cherif, Mehdi; Granados, Monica; Duffy, Sean; Robert, Pauline; Péquin, Bérangère; Mohit, Vani; McKindsey, Christopher W; Archambault, Philippe; Myrand, Bruno; Lovejoy, Connie; Tremblay, Réjean; Plourde, Stéphane; Fussmann, Gregor F

    2016-01-01

    Mussel aquaculture has expanded worldwide and it is important to assess its impact on the water column and the planktonic food web to determine the sustainability of farming practices. Mussel farming may affect the planktonic food web indirectly by excreting bioavailable nutrients in the water column (a short-term effect) or by increasing nutrient effluxes from biodeposit-enriched sediments (a long-term effect). We tested both of these indirect effects in a lagoon by using plankton-enclosing benthocosms that were placed on the bottom of a shallow lagoon either inside of a mussel farm or at reference sites with no history of aquaculture. At each site, half of the benthocosms were enriched with seawater that had held mussels (excretion treatment), the other half received non-enriched seawater as a control treatment. We monitored nutrients ([PO43-] and [NH4+]), dissolved oxygen and plankton components (bacteria, the phytoplankton and the zooplankton) over 5 days. We found a significant relationship between long-term accumulation of mussel biodeposits in sediments, water-column nutrient concentrations and plankton growth. Effects of mussel excretion were not detected, too weak to be significant given the spatial and temporal variability observed in the lagoon. Effects of mussels on the water column are thus likely to be coupled to benthic processes in such semi-enclosed water bodies. PMID:27249793

  6. Evidence of Two Component Accretion Flows as revealed by time lag properties: Results of Long-Term RXTE/ASM Data Analysis

    NASA Astrophysics Data System (ADS)

    Ghosh, Arindam; Chakrabarti, Sandip Kumar

    2016-07-01

    Long-term RXTE/ASM X-ray data of several Galactic black hole candidates (BHCs) are analyzed. The results of this analysis show the existence of two component accretion flow (TCAF) in both low-mass and high-mass X-ray binaries (LMXBs & HMXBs). Large disks with long viscous timescales in the accreting matter with high angular momentum are prevalent in LMXBs due to processes like Roche lobe overflow, while small disks with little viscous delays are observed in HMXBs, primarily because of wind accretion. Two parameters are defined as photon indices, independent of the choice of a BHC, in order to find correlation between the two components, namely, the Keplerian disk component and the sub-Keplerian component, thereby estimating the time lag between two aforesaid timescales. Fluxes of hard and soft photons are observed to be anti-correlated with respect to these photon indices. The time lags give us an idea of the viscosity in the Keplerian component.

  7. In Vitro Testing of an Implantable Wireless Telemetry System for Long-Term Electromyography Recordings in Large Animals.

    PubMed

    Kneisz, Lukas; Unger, Ewald; Lanmüller, Hermann; Mayr, Winfried

    2015-10-01

    Multichannel bio-signal recording in undisturbed in vivo conditions is a frequent demand in experimental work for development of methodology and associated equipment for functional electrical stimulation (FES) application, limb prosthesis, and diagnostic tools in contemporary rehabilitation efforts. Intramuscular electromyogram (EMG) recordings can provide comprehensive insight in complex interactions of agonistic and antagonistic muscles during movement tasks and in contrast act as reliable control signals for both neuroprosthesis and mechanical prosthesis. We fabricated a fully implantable device, which is capable of recording electromyography signals from inside a body and transmit these signals wirelessly to an external receiver. The developed analog front end uses only two electrodes per channel, provides a gain of 60 dB, and incorporates a band pass filter with lower cut-off frequency of 4 Hz and upper cut-off frequency of 480 Hz. The bidirectional wireless data link, which operates in the 2.4 GHz Industrial, Scientific and Medical band, is designed for transmission distances of 10 m using an application data rate of 1 kSps for each of the two channels. Performed in vitro tests with the devices coated in epoxy resin and inserted into a phantom with tissue-equivalent characteristics confirmed the functionality of our concept and the measurement results are consistent with those from preceding simulations. PMID:26471141

  8. Biodiversity-ecosystem functioning relationships in long-term time series and palaeoecological records: deep sea as a test bed.

    PubMed

    Yasuhara, Moriaki; Doi, Hideyuki; Wei, Chih-Lin; Danovaro, Roberto; Myhre, Sarah E

    2016-05-19

    The link between biodiversity and ecosystem functioning (BEF) over long temporal scales is poorly understood. Here, we investigate biological monitoring and palaeoecological records on decadal, centennial and millennial time scales from a BEF framework by using deep sea, soft-sediment environments as a test bed. Results generally show positive BEF relationships, in agreement with BEF studies based on present-day spatial analyses and short-term manipulative experiments. However, the deep-sea BEF relationship is much noisier across longer time scales compared with modern observational studies. We also demonstrate with palaeoecological time-series data that a larger species pool does not enhance ecosystem stability through time, whereas higher abundance as an indicator of higher ecosystem functioning may enhance ecosystem stability. These results suggest that BEF relationships are potentially time scale-dependent. Environmental impacts on biodiversity and ecosystem functioning may be much stronger than biodiversity impacts on ecosystem functioning at long, decadal-millennial, time scales. Longer time scale perspectives, including palaeoecological and ecosystem monitoring data, are critical for predicting future BEF relationships on a rapidly changing planet. PMID:27114583

  9. Functional Sensory-Motor Performance Following Long Term Space Flight: The First Results of "Field Test" Experiment

    NASA Technical Reports Server (NTRS)

    Tomilovskaya, E. S.; Rukavishnikov, I. V.; Kofman, I. S.; Kitov, V. V.; Grishin, A. P.; Yu, N.; Lysova.; Cerisano, J. M.; Kozlovskaya, I. B.; Reschke, M. F.

    2014-01-01

    quantifying the coordination and timing of relatively simple basic movements - transition from seated and prone positions to standing, walking, stepping over obstacles, tandem walking, muscle compliance, as well as characteristics of postural sway and orthostatic tolerance. Testing for changes in these parameters have been initiated in the medical tent at the landing site. The first set of experiments showed that during the first hour after landing, cosmonauts and astronauts were able to execute (although slower and with more effort than preflight) simple movements such as egress from a seated or prone position and also to remain standing for 3.5 minutes without exhibiting pronounced cardiovascular changes. More challenging tests, however, demonstrated a prominent reduction in coordination - the obstacle task, for example, was performed at much slower speed and with a marked overestimation of the obstacle height and tandem walking was greatly degraded suggesting significant changes in proprioception, brainstem and vestibular function. There is some speculation that the neural changes, either from the bottom-up or top down may be long lasting; requiring compensatory responses that will modify or mask the adverse responses we have observed. Furthermore, these compensatory responses may actually be beneficial, helping achieve a more rapid adaptation to both weightlessness and a return to earth.

  10. Analysis of long-term mechanical grooming on large-scale test panels coated with an antifouling and a fouling-release coating.

    PubMed

    Hearin, John; Hunsucker, Kelli Z; Swain, Geoffrey; Stephens, Abraham; Gardner, Harrison; Lieberman, Kody; Harper, Michael

    2015-01-01

    Long-term grooming tests were conducted on two large-scale test panels, one coated with a fluorosilicone fouling-release (FR) coating, and one coated with a copper based ablative antifouling (AF) coating. Mechanical grooming was performed weekly or bi-weekly using a hand operated, electrically powered, rotating brush tool. The results indicate that weekly grooming was effective at removing loose or heavy biofilm settlement from both coatings, but could not prevent the permanent establishment of low-profile tenacious biofilms. Weekly grooming was very effective at preventing macrofouling establishment on the AF coating. The effectiveness of weekly grooming at preventing macrofouling establishment on the FR coating varied seasonally. The results suggest that frequent mechanical grooming is a viable method to reduce the fouling rating of ships' hulls with minimal impact to the coating. Frequent grooming could offer significant fuel savings while reducing hull cleaning frequencies and dry dock maintenance requirements. PMID:26359541