Science.gov

Sample records for boron-dilution transient tests

  1. On the Application of CFD Modeling for the Prediction of the Degree of Mixing in a PWR During a Boron Dilution Transient

    SciTech Connect

    Lycklama, Jan-Aiso; Hoehne, Thomas

    2006-07-01

    In a Pressurized Water Reactor, negative reactivity is present in the core by means of Boric acid as a soluble neutron absorber in the coolant water. During a so-called Boron Dilution Transient (BDT), a de-borated slug of coolant water is transported from the cold leg into the reactor vessel, and the borated coolant water is diluted by mixing with this un-borated water. The resulting decrease in the boron concentration leads to an insertion of positive reactivity in the core, which may lead to a reactivity excursion. The associated power peak may damage the fuel rods. The mixing of borated and un-borated water in downcomer and lower plenum is an important process, because it mitigates the degree of reactivity insertion. In the present study the application of Computational Fluid Dynamics (CFD) for the prediction of this mixing of un-borated with borated water in the RPV has been assessed. The analyses have been compared with the measurement data from the Rossendorf coolant mixing model (ROCOM) experiment. The ROCOM test facility represents the primary cooling system of a KONVOI type of PWR (1300 MW{sub el}). In spite of the complicated spatial, temporal, and geometrical aspects of the flow in the RPV, the agreement between the calculated and the experimental data is good. The CFD model tends to slightly under predict the degree of mixing in the RPV resulting in a slight under-prediction of the boron concentration at the core. (authors)

  2. Analysis of boron dilution in a four-loop PWR

    SciTech Connect

    Sun, J.G.; Sha, W.T.

    1995-12-31

    Thermal mixing and boron dilution in a pressurized water reactor were analyzed with COMMIX codes. The reactor system was the four loop Zion reactor. Two boron dilution scenarios were analyzed. In the first scenario, the plant is in cold shutdown and the reactor coolant system has just been filled after maintenance on the steam generators. To flush the air out of the steam generator tubes, a reactor coolant pump (RCP) is started, with the water in the pump suction line devoid of boron and at the same temperature as the coolant in the system. In the second scenario, the plant is at hot standby and the reactor coolant system has been heated up to operating temperature after a long outage. It is assumed that an RCP is started, with the pump suction line filled with cold unborated water, forcing a slug of diluted coolant down the downcomer and subsequently through the reactor core. The subsequent transient thermal mixing and boron dilution that would occur in the reactor system is simulated for these two scenarios. The reactivity insertion rate and the total reactivity are evaluated.

  3. Igniter heater EMI transient test

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    Testing to evaluate Redesigned Solid Rocket Motor igniter heater electromagnetic interference (EMI) effects on the Safe and Arm (S and A) device was completed. It was suspected that EMI generated by the igniter heater and it's associated electromechanical relay could cause a premature firing of the NASA Standard Initiators (NSIs) inside the S and A. The maximum voltage induced into the NSI fire lines was 1/4 of the NASA specified no-fire limit of one volt (SKB 26100066). As a result, the igniter heaters are not expected to have any adverse EMI effects on the NSIs. The results did show, however, that power switching causes occasional high transients within the igniter heater power cable. These transients could affect the sensitive equipment inside the forward skirt. It is therefore recommended that the electromechanical igniter heater relays be replaced with zero crossing solid state relays. If the solid state relays are installed, it is also recommended that they be tested for EMI transient effects.

  4. Transient Pressure Test Article Test Program

    NASA Technical Reports Server (NTRS)

    Vibbart, Charles M.

    1989-01-01

    The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

  5. Stability Test for Transient-Temperature Calculations

    NASA Technical Reports Server (NTRS)

    Campbell, W.

    1984-01-01

    Graphical test helps assure numerical stability of calculations of transient temperature or diffusion in composite medium. Rectangular grid forms basis of two-dimensional finite-difference model for heat conduction or other diffusion like phenomena. Model enables calculation of transient heat transfer among up to four different materials that meet at grid point.

  6. Mixing phenomena of interest to boron dilution during small break LOCAs in PWRs. Revision 7/95

    SciTech Connect

    Nourbakhsh, H.P.; Cheng, Z.

    1995-07-01

    This paper presents the results of a study of mixing phenomena related to boron dilution during small break loss of coolant accidents (LOCAs) in pressurized water reactors (PWRs). Boron free condensate can accumulate in the cold leg loop seals when the reactor is operating in a reflux/boiler-condenser mode. A problem may occur when subsequent change in flow conditions such as loop seal clearing or re-establishment of natural circulation flow drive the diluted water in the loop seals into the reactor core without sufficient mixing with the highly borated water in the reactor downcomer and lower plenum. The resulting low boron concentration coolant entering the core may cause a power excursion leading to fuel failure. The mixing processes associated with a slow moving stream of diluted water through the loop seal to the core are examined in this paper. Bounding calculations for boron concentration of coolant entering the core during a small break LOCA in a typical Westinghouse-designed four-loop plant are also presented.

  7. Future Transient Testing of Advanced Fuels

    SciTech Connect

    Jon Carmack

    2009-09-01

    The transient in-reactor fuels testing workshop was held on May 4–5, 2009 at Idaho National Laboratory. The purpose of this meeting was to provide a forum where technical experts in transient testing of nuclear fuels could meet directly with technical instrumentation experts and nuclear fuel modeling and simulation experts to discuss needed advancements in transient testing to support a basic understanding of nuclear fuel behavior under off-normal conditions. The workshop was attended by representatives from Commissariat à l'Énergie Atomique CEA, Japanese Atomic Energy Agency (JAEA), Department of Energy (DOE), AREVA, General Electric – Global Nuclear Fuels (GE-GNF), Westinghouse, Electric Power Research Institute (EPRI), universities, and several DOE national laboratories. Transient testing of fuels and materials generates information required for advanced fuels in future nuclear power plants. Future nuclear power plants will rely heavily on advanced computer modeling and simulation that describes fuel behavior under off-normal conditions. TREAT is an ideal facility for this testing because of its flexibility, proven operation and material condition. The opportunity exists to develop advanced instrumentation and data collection that can support modeling and simulation needs much better than was possible in the past. In order to take advantage of these opportunities, test programs must be carefully designed to yield basic information to support modeling before conducting integral performance tests. An early start of TREAT and operation at low power would provide significant dividends in training, development of instrumentation, and checkout of reactor systems. Early start of TREAT (2015) is needed to support the requirements of potential users of TREAT and include the testing of full length fuel irradiated in the FFTF reactor. The capabilities provided by TREAT are needed for the development of nuclear power and the following benefits will be realized by the

  8. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Transient test cycle generation. 86... Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto... question must be used. The generation of the maximum torque curve is described in § 86.1332. (3) The...

  9. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Transient test cycle generation. 86... Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto... question must be used. The generation of the maximum torque curve is described in § 86.1332. (3) The...

  10. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Transient test cycle generation. 86... Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto... question must be used. The generation of the maximum torque curve is described in § 86.1332. (3) The...

  11. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86... Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto... question must be used. The generation of the maximum torque curve is described in § 86.1332. (3) The...

  12. Transient Molecular Transfer During Vacuum Testing

    NASA Technical Reports Server (NTRS)

    Perry, Radford L.

    2011-01-01

    A common question in contamination budgeting involves the loss of collected volatiles during ambient I&T activity under vacuum and the resultant cross-contamination from outgassing. (1) How much of the material collected under ambient conditions evaporates under vacuum? (2) Why do pristine surfaces sometimes show increased molecular contamination after vacuum bakeout? (3) How much of the collected molecular contamination is transient (i.e. migratory) and how much is permanent? Measuring the transient deposition may be accomplished using a thermally passive QCM

  13. Thermal-Transient Testing Of Turbine Blades

    NASA Technical Reports Server (NTRS)

    Wagner, William R.; Pidcoke, Louis H.

    1990-01-01

    Testing apparatus applies pulses of heat to turbine blade to determine resistance to thermal fatigue. Uses nonintrusive inductive heating and records distribution of temperature on blade with infrared video camera. Allows precise control of heating and cooling. Designed for testing blades used in advanced high-pressure, high-temperature turbines.

  14. 40 CFR 86.1333 - Transient test cycle generation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I((f) (1...) in these listings. (1) To unnormalize rpm, use the following equations: (i) For diesel engines... Otto-cycle engines: ER28AP14.007 Where: Max Test Speed = the maximum test speed as calculated in 40...

  15. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  16. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  17. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  18. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate... cycles. The heavy-duty transient engine cycles for Otto-cycle and diesel engines are listed in appendix I... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  19. Alternatives Analysis for the Resumption of Transient Testing Program

    SciTech Connect

    Lee Nelson

    2013-11-01

    An alternatives analysis was performed for resumption of transient testing. The analysis considered eleven alternatives – including both US international facilities. A screening process was used to identify two viable alternatives from the original eleven. In addition, the alternatives analysis includes a no action alternative as required by the National Environmental Policy Act (NEPA). The alternatives considered in this analysis included: 1. Restart the Transient Reactor Test Facility (TREAT) 2. Modify the Annular Core Research Reactor (ACRR) which includes construction of a new hot cell and installation of a new hodoscope. 3. No Action

  20. Plasma-Catalysis During Temperature Transient Testing

    SciTech Connect

    Hoard, John

    2001-08-05

    A combination of catalysts is used together with nonthermal plasma in simulated diesel exhaust, while the gas temperature is varied. The catalysts both store and convert pollutants. As a result, pollutant concentrations during temperature ramps are different than those at steady state conditions. The data are presented for plasma followed by BaY, alumina, and Pt catalysts in simulated exhaust. When temperature ramps from high to low, apparent NOx conversion is quite high. However, when temperature is ramped from low to high, lower apparent conversions are seen. In a typical test cycle, average NOx conversion between 100 and 400 C is 60%. Peak conversion during the down ramp is over 90%, and minimum conversion during the up ramp is 30%. The composition of the effluent gas also varies during the temperature cycle. Intermediates such as methyl nitrate and hydrogen cyanide are not present following the combination of catalysts.

  1. A Technique for Transient Thermal Testing of Thick Structures

    NASA Technical Reports Server (NTRS)

    Horn, Thomas J.; Richards, W. Lance; Gong, Leslie

    1997-01-01

    A new open-loop heat flux control technique has been developed to conduct transient thermal testing of thick, thermally-conductive aerospace structures. This technique uses calibration of the radiant heater system power level as a function of heat flux, predicted aerodynamic heat flux, and the properties of an instrumented test article. An iterative process was used to generate open-loop heater power profiles prior to each transient thermal test. Differences between the measured and predicted surface temperatures were used to refine the heater power level command profiles through the iteration process. This iteration process has reduced the effects of environmental and test system design factors, which are normally compensated for by closed-loop temperature control, to acceptable levels. The final revised heater power profiles resulted in measured temperature time histories which deviated less than 25 F from the predicted surface temperatures.

  2. Intelligent transient transitions detection of LRE test bed

    NASA Astrophysics Data System (ADS)

    Zhu, Fengyu; Shen, Zhengguang; Wang, Qi

    2013-01-01

    Health Monitoring Systems is an implementation of monitoring strategies for complex systems whereby avoiding catastrophic failure, extending life and leading to improved asset management. A Health Monitoring Systems generally encompasses intelligence at many levels and sub-systems including sensors, actuators, devices, etc. In this paper, a smart sensor is studied, which is use to detect transient transitions of liquid-propellant rocket engines test bed. In consideration of dramatic changes of variable condition, wavelet decomposition is used to work real time in areas. Contrast to traditional Fourier transform method, the major advantage of adding wavelet analysis is the ability to detect transient transitions as well as obtaining the frequency content using a much smaller data set. Historically, transient transitions were only detected by offline analysis of the data. The methods proposed in this paper provide an opportunity to detect transient transitions automatically as well as many additional data anomalies, and provide improved data-correction and sensor health diagnostic abilities. The developed algorithms have been tested on actual rocket test data.

  3. Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)

    SciTech Connect

    Bradley K. Heath

    2014-03-01

    This work supports the restart of transient testing in the United States using the Department of Energy’s Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show that fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuel’s cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISON’s results. BISON’s models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.

  4. Pressure transient testing at Cerro Prieto Geothermal Field

    SciTech Connect

    Rivera, J.R.; Samaniego, F.V.; Schroeder, R.C.

    1980-01-01

    Because of the inherent problems in applying pressure build-up tests to wells producing two-phase fluids, it was decided to use variable flow tests of short duration known as two-rates tests. In these tests of variation in the well flow rates can be used to intepret the transient pressure response in order to determine reservoir parameters such as permeability, well-bore damage and mean reservoir pressure in the well drainage area. Some examples will illustrate the application of this technique. 11 refs.

  5. Analysis of Transient Pressure Tests for Olkaria Exploration Wells

    SciTech Connect

    Haukwa, Charles B.

    1987-01-20

    Analysis of transient pressure tests for Olkaria West wells shows that both infinite acting and double porosity models can be used to analyze the well behaviour and infer reservoir properties from fall-off steps of long enough duration, in wells where no significant thermal recovery occurs. The double porosity model gives better estimates of reservoir properties than the infinite acting model, for long fall-off steps in wells intercepting fractures. Semilog methods give fairly good estimates of reservoir transmissivity for the long fall-off steps but are highly inaccurate when used independently, especially for the short fall-off steps conducted in most of the wells. Double porosity models can also be used for recovery test analyses where two phase transients are not significant. 6 refs., 11 figs., 8 tabs.

  6. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... transient testing? 1039.510 Section 1039.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure emissions by testing the engine on a dynamometer with one of the following transient duty cycles to...

  7. Transient well testing in two-phase geothermal reservoirs

    SciTech Connect

    Aydelotte, S.R.

    1980-03-01

    A study of well test analysis techniques in two-phase geothermal reservoirs has been conducted using a three-dimensional, two-phase, wellbore and reservoir simulation model. Well tests from Cerro Prieto and the Hawaiian Geothermal project have been history matched. Using these well tests as a base, the influence of reservoir permeability, porosity, thickness, and heat capacity, along with flow rate and fracturing were studied. Single and two-phase transient well test equations were used to analyze these tests with poor results due to rapidly changing fluid properties and inability to calculate the flowing steam saturation in the reservoir. The injection of cold water into the reservoir does give good data from which formation properties can be calculated.

  8. Large transient fault current test of an electrical roll ring

    NASA Technical Reports Server (NTRS)

    Yenni, Edward J.; Birchenough, Arthur G.

    1992-01-01

    The space station uses precision rotary gimbals to provide for sun tracking of its photoelectric arrays. Electrical power, command signals and data are transferred across the gimbals by roll rings. Roll rings have been shown to be capable of highly efficient electrical transmission and long life, through tests conducted at the NASA Lewis Research Center and Honeywell's Satellite and Space Systems Division in Phoenix, AZ. Large potential fault currents inherent to the power system's DC distribution architecture, have brought about the need to evaluate the effects of large transient fault currents on roll rings. A test recently conducted at Lewis subjected a roll ring to a simulated worst case space station electrical fault. The system model used to obtain the fault profile is described, along with details of the reduced order circuit that was used to simulate the fault. Test results comparing roll ring performance before and after the fault are also presented.

  9. Fast reactor safety testing in Transient Reactor Test (TREAT) in the 1980s

    SciTech Connect

    Wright, A.E. ); Dutt, D.S. ); Harrison, L.J. )

    1990-01-01

    Several series of fast reactor safety tests were performed in TREAT during the 1980s. These focused on the transient behavior of full-length oxide fuels (US reference, UK reference, and US advanced design) and on modern metallic fuels. Most of the tests addressed fuel behavior under transient overpower or loss-of-flow conditions. The test series were the PFR/TREAT tests; the RFT, TS, CDT, and RX series on oxide fuels; and the M series on metallic fuels. These are described in terms of their principal results and relevance to analyses and safety evaluation. 4 refs., 3 tabs.

  10. Modeling transient streaming potentials in falling-head permeameter tests.

    PubMed

    Malama, Bwalya; Revil, André

    2014-01-01

    We present transient streaming potential data collected during falling-head permeameter tests performed on samples of two sands with different physical and chemical properties. The objective of the work is to estimate hydraulic conductivity (K) and the electrokinetic coupling coefficient (Cl ) of the sand samples. A semi-empirical model based on the falling-head permeameter flow model and electrokinetic coupling is used to analyze the streaming potential data and to estimate K and Cl . The values of K estimated from head data are used to validate the streaming potential method. Estimates of K from streaming potential data closely match those obtained from the associated head data, with less than 10% deviation. The electrokinetic coupling coefficient was estimated from streaming potential vs. (1) time and (2) head data for both sands. The results indicate that, within limits of experimental error, the values of Cl estimated by the two methods are essentially the same. The results of this work demonstrate that a temporal record of the streaming potential response in falling-head permeameter tests can be used to estimate both K and Cl . They further indicate the potential for using transient streaming potential data as a proxy for hydraulic head in hydrogeology applications.

  11. Transient rotor dynamic rub phenomena - Theory and test

    NASA Technical Reports Server (NTRS)

    Kascak, A. F.; Montaque, G.; Palazzolo, A. B.

    1987-01-01

    This paper develops an implicit integration scheme for transient rotor dynamic rub prediction and includes a correlation study with actual test results. A Nordsieck-like numerical integration scheme is applied directly to the second-order equations of motion. The assumption that forces and torques on the rotor are functions of the position and velocity at the point of application and its nearest neighbor is made in order to make the computational time proportional to the number of elements in the rotor dynamics model rather than the cube of the number. The test rig consists of a turbine driven, flexible shaft supported by squeeze film dampers. The blade loss event occurs due to collision of a balance bolt on one of the disks with a high speed plunger. The rotor is seen to spiral outward and contact against a stationary assemblage of seal shoes.

  12. Multi-axis transient vibration testing of space objects: Test philosophy, test facility, and control strategy

    NASA Technical Reports Server (NTRS)

    Lachenmayr, Georg

    1992-01-01

    IABG has been using various servohydraulic test facilities for many years for the reproduction of service loads and environmental loads on all kinds of test objects. For more than 15 years, a multi-axis vibration test facility has been under service, originally designed for earthquake simulation but being upgraded to the demands of space testing. First tests with the DFS/STM showed good reproduction accuracy and demonstrated the feasibility of transient vibration testing of space objects on a multi-axis hydraulic shaker. An approach to structural qualification is possible by using this test philosophy. It will be outlined and its obvious advantages over the state-of-the-art single-axis test will be demonstrated by example results. The new test technique has some special requirements to the test facility exceeding those of earthquake testing. Most important is the high reproduction accuracy demanded for a sophisticated control system. The state-of-the-art approach of analog closed-loop control circuits for each actuator combined with a static decoupling network and an off-line iterative waveform control is not able to meet all the demands. Therefore, the future over-all control system is implemented as hierarchical full digital closed-loop system on a highly parallel transputer network. The innermost layer is the digital actuator controller, the second one is the MDOF-control of the table movement. The outermost layer would be the off-line iterative waveform control, which is dedicated only to deal with the interaction of test table and test object or non-linear effects. The outline of the system will be presented.

  13. Spatial weighting functions: transient hydraulic tests and heterogeneous media.

    PubMed

    Molz, Fred J; Guan, Jianyong; Wang, Jinjun

    2005-01-01

    To improve understanding of property measurements in heterogeneous media, an energy-based weighting function concept is developed. In (assumed) homogeneous media, the instrument spatial weighting function (ISWF) depends only on the energy dissipation distribution set up by the measurement procedure and it reduces to simply inverse sample volume (uniform weighting) for 1-D parallel flow case (ideal permeameter). For 1-D transient flow in homogeneous media, such as with slug tests, the ISWF varies with position and time, with 95% of the total weighting contained within 115 well radii, even late in the test. In the heterogeneous case, the determination of the ISWF is connected to the problem of determining an equivalent hydraulic conductivity (K), where the criterion for equivalence is based on equal energy dissipation rate rather than equal volume discharge. The discharge-based equivalent K (K(E)) and the energy-based equivalent K in heterogeneous media (K(eh)) are not equal in general, with K(eh) typically above the nodal arithmetic mean K. The possibly more fundamental problem is that as one makes K measurements in heterogeneous media at different locations or on different cores of heterogeneous materials, the ISWF will be heterogeneity dependent, implying that the averaging process resulting in the equivalent K value also varies with position. If the testing procedure is transient, then the averaging process varies with time. This suggests a fundamental ambiguity in the interpretation of hydraulic conductivity measurements in heterogeneous media that may impact how we approach modeling and prediction in a practical sense (Molz 2003). Further research is suggested.

  14. Transient Testing of Nuclear Fuels and Materials in United States

    SciTech Connect

    Daniel M. Wachs

    2012-12-01

    The US Department of Energy (DOE) has been engaged in an effort to develop and qualify next generation LWR fuel with enhanced performance and safety and reduced waste generation since 2010. This program, which has emphasized collaboration between the DOE, U.S. national laboratories and nuclear industry, was refocused from enhanced performance to enhanced accident tolerance following the events at Fukushima in 2011. Accident tolerant fuels have been specifically described as fuels that, in comparison with standard UO2-Zircaloy, can tolerate loss of active cooling in the reactor core for a considerably longer time period (depending on the LWR system and accident scenario) while maintaining or improving the fuel performance during normal operations, operational transients, as well as design-basis and beyond design-basis events. The program maintains an ambitious goal to insert a lead test assembly (LTA) of the new design into a commercial power reactor by 2022 .

  15. Results from transient tests and spherical valve closure tests, Raccoon Mountain Pumped-Storage Plant

    SciTech Connect

    March, P.A.

    1984-09-01

    Tests were conducted at the Raccoon Mountain Pumped-Storage Plant to obtain data on hydraulic system characteristics during transient-state operation, to compare measured values for system pressures and surge levels with design values, to provide information for review of hydaulic transient computations, and to provide confirmation that the spherical valves are capable of shutting off plant flow under emergency conditions. The tests included single-unit load rejection, single-unit pump power loss, multi-unit emergency shutdown from generating, multi-unit emergency shutdown from pumping, and spherical valve closure.

  16. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... compare with the established criteria as specified in 40 CFR 1065.514 to confirm that the test is valid... transient testing? 1039.510 Section 1039.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure...

  17. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR 1065.514 to confirm that the test is valid. ... transient testing? 1039.510 Section 1039.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure...

  18. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR 1065.514 to confirm that the test is valid. ... transient testing? 1039.510 Section 1039.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure...

  19. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... established criteria as specified in 40 CFR 1065.514 to confirm that the test is valid. ... transient testing? 1039.510 Section 1039.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure...

  20. Transient productivity index for numerical well test simulations

    SciTech Connect

    Blanc, G.; Ding, D.Y.; Ene, A.

    1997-08-01

    The most difficult aspect of numerical simulation of well tests is the treatment of the Bottom Hole Flowing (BHF) Pressure. In full field simulations, this pressure is derived from the Well-block Pressure (WBP) using a numerical productivity index which accounts for the grid size and permeability, and for the well completion. This productivity index is calculated assuming a pseudo-steady state flow regime in the vicinity of the well and is therefore constant during the well production period. Such a pseudo-steady state assumption is no longer valid for the early time of a well test simulation as long as the pressure perturbation has not reached several grid-blocks around the well. This paper offers two different solutions to this problem: (1) The first one is based on the derivation of a Numerical Transient Productivity Index (NTPI) to be applied to Cartesian grids; (2) The second one is based on the use of a Corrected Transmissibility and Accumulation Term (CTAT) in the flow equation. The representation of the pressure behavior given by both solutions is far more accurate than the conventional one as shown by several validation examples which are presented in the following pages.

  1. Barometric pressure transient testing applications at the Nevada Test Site: formation permeability analysis. Final report

    SciTech Connect

    Hanson, J.M.

    1984-12-01

    The report evaluates previous investigations of the gas permeability of the rock surrounding emplacement holes at the Nevada Test Site. The discussion sets the framework from which the present uncertainty in gas permeability can be overcome. The usefulness of the barometric pressure testing method has been established. Flow models were used to evaluate barometric pressure transients taken at NTS holes U2fe, U19ac and U20ai. 31 refs., 103 figs., 18 tabs. (ACR)

  2. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 2 2013-07-01 2013-07-01 false Transient Test Driving Cycle E Appendix... Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by the... determine a valid test. (II) Driving cycle. The following table shows the time speed relationship for...

  3. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 2 2014-07-01 2014-07-01 false Transient Test Driving Cycle E Appendix... Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by the... determine a valid test. (II) Driving cycle. The following table shows the time speed relationship for...

  4. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 2 2012-07-01 2012-07-01 false Transient Test Driving Cycle E Appendix... Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by the... determine a valid test. (II) Driving cycle. The following table shows the time speed relationship for...

  5. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm... 40 Protection of Environment 34 2013-07-01 2013-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the...

  6. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the...

  7. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm... 40 Protection of Environment 33 2014-07-01 2014-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the...

  8. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm... 40 Protection of Environment 34 2012-07-01 2012-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the...

  9. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm... 40 Protection of Environment 33 2011-07-01 2011-07-01 false What transient duty cycles apply for... Procedures § 1048.510 What transient duty cycles apply for laboratory testing? (a) Starting with the...

  10. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... E to Subpart S of Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR.../Maintenance Program Requirements Pt. 51, Subpt. S, App. E Appendix E to Subpart S of Part 51—Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by...

  11. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... E to Subpart S of Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR.../Maintenance Program Requirements Pt. 51, Subpt. S, App. E Appendix E to Subpart S of Part 51—Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by...

  12. RELAP5 Prediction of Transient Tests in the RD-14 Test Facility

    SciTech Connect

    Lee, Sukho; Kim, Manwoong; Kim, Hho-Jung; Lee, John C.

    2005-09-15

    Although the RELAP5 computer code has been developed for best-estimate transient simulation of a pressurized water reactor and its associated systems, it could not assess the thermal-hydraulic behavior of a Canada deuterium uranium (CANDU) reactor adequately. However, some studies have been initiated to explore the applicability for simulating a large-break loss-of-coolant accident in CANDU reactors. In the present study, the small-reactor inlet header break test and the steam generator secondary-side depressurization test conducted in the RD-14 test facility were simulated with the RELAP5/MOD3.2.2 code to examine its extended capability for all the postulated transients and accidents in CANDU reactors. The results were compared with experimental data and those of the CATHENA code performed by Atomic Energy of Canada Limited.In the RELAP5 analyses, the heated sections in the facility were simulated as a multichannel with five pipe models, which have identical flow areas and hydraulic elevations, as well as a single-pipe model.The results of the small-reactor inlet header break and the steam generator secondary-side depressurization simulations predicted experimental data reasonably well. However, some discrepancies in the depressurization of the primary heat transport system after the header break and consequent time delay of the major phenomena were observed in the simulation of the small-reactor inlet header break test.

  13. Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test.

    PubMed

    Sheng, Chunchen; Hu, Peng; Cheng, Xiaofang

    2016-06-01

    Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m(2) with high accuracy and the response time of less than 10 s.

  14. Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test.

    PubMed

    Sheng, Chunchen; Hu, Peng; Cheng, Xiaofang

    2016-06-01

    Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m(2) with high accuracy and the response time of less than 10 s. PMID:27370482

  15. Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test

    NASA Astrophysics Data System (ADS)

    Sheng, Chunchen; Hu, Peng; Cheng, Xiaofang

    2016-06-01

    Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m2 with high accuracy and the response time of less than 10 s.

  16. TS-1 and TS-2 transient overpower tests on FFTF fuel

    SciTech Connect

    Pitner, A.L.; Ferrell, P.C.; Culley, G.E.; Weber, E.T.

    1985-10-03

    The TS-1 and TS-2 TREAT transient experiments subjected a low burnup (2 MWd/kg) and a medium burnup (58 MWd/kg), respectively, FFTF irradiated fuel pin to unprotected 5 cents/s overpower transient conditions. The fuel pin failure response was similar in the two tests, which demonstrated a large margin to failure (P/P/sub 0/ > 3) and a favorable upper level failure location. Thus, for these transient conditions, burnup effects on transient performance appeared to be minimal in the range tested. Pin disruption in the medium burnup TS-2 test was more severe due to the higher fission gas pressurization, but failure occurred at only a 5% lower power level than for the low burnup TS-1 fuel pin. Both tests exhibited axial extrusion of molten fuel to the region above the fuel column several seconds before pin failure, demonstrating a potentially beneficial inherent safety mechanism to delay failure and mitigate accident consequences.

  17. Data acquisition and interpretation of horizontal well pressure-transient tests

    SciTech Connect

    Lichtenberger, G.J. )

    1994-02-01

    For both vertical and horizontal wells, pressure-transient testing is a powerful tool for evaluating in-situ reservoir and wellbore parameters that describe the production characteristics of a well. Although many operators use horizontal well technology, many engineers consider pressure-transient testing of horizontal wells impractical and too complex. Experience has shown, however, that with adequate test planning, based on the concept of low regimes and focused on optimizing test conditions, horizontal well testing can be as successful as vertical well testing. Using the concept of flow regimes and drawing on analogies with vertical wells, this paper reviews the pressure-transient behavior of horizontal wells. Practical guidelines are given for planning, executing, and interpreting horizontal well tests. The application of various interpretation techniques is illustrated with field examples.

  18. [Testing Research of Transient Temperature Distribution for the Barrel Surface by Speckle Pattern Interferometry].

    PubMed

    Lang, Wen-jie; Chen, Guo-guang; Tian, Xiao-li; Xin, Chang-fan

    2016-02-01

    There are some problems in the traditional transient temperature test equipment. The thermal inertia is great, and can only be a single point of detection. To be able to achieve real-time monitoring for transient temperature distribution change of the gun body surface, the test system for transient temperature distribution was designed based on Speckle Pattern Interferometry (SPI) and spectroscopy. In the system, transient temperature change of the barrel led to slight deformation, and it was converted into speckle interference fringes by SPI technology. Spectral distribution function was obtained by the interference fringes by the Fourier transform, so the information of interference fringe deformation was incorporated into the frequency domain. The data of temperature distribution can be inverted on any sampling time by spectral distribution function. In experiments, the ZX-FB1 fiber optic thermometer was used to test transient temperature on a single point as the standard value. The center wavelength of the laser was 555 nm, and the speckle pattern interference fringes were collected by area array CCD. Image Recognition-Speckle Pattern Interferometry (IR-SPI) and Fourier Transform-Speckle Pattern Interferometry (FT-SPI) were used in experiments, the calculation of transient temperature was completed through two methods. Experimental results are that both methods can achieve transient temperature detection. But the FT-SPI is higher in terms of accuracy, and it can effectively overcome the gross error caused by the surface defects, paint wear and other similar problems. PMID:27209730

  19. [Testing Research of Transient Temperature Distribution for the Barrel Surface by Speckle Pattern Interferometry].

    PubMed

    Lang, Wen-jie; Chen, Guo-guang; Tian, Xiao-li; Xin, Chang-fan

    2016-02-01

    There are some problems in the traditional transient temperature test equipment. The thermal inertia is great, and can only be a single point of detection. To be able to achieve real-time monitoring for transient temperature distribution change of the gun body surface, the test system for transient temperature distribution was designed based on Speckle Pattern Interferometry (SPI) and spectroscopy. In the system, transient temperature change of the barrel led to slight deformation, and it was converted into speckle interference fringes by SPI technology. Spectral distribution function was obtained by the interference fringes by the Fourier transform, so the information of interference fringe deformation was incorporated into the frequency domain. The data of temperature distribution can be inverted on any sampling time by spectral distribution function. In experiments, the ZX-FB1 fiber optic thermometer was used to test transient temperature on a single point as the standard value. The center wavelength of the laser was 555 nm, and the speckle pattern interference fringes were collected by area array CCD. Image Recognition-Speckle Pattern Interferometry (IR-SPI) and Fourier Transform-Speckle Pattern Interferometry (FT-SPI) were used in experiments, the calculation of transient temperature was completed through two methods. Experimental results are that both methods can achieve transient temperature detection. But the FT-SPI is higher in terms of accuracy, and it can effectively overcome the gross error caused by the surface defects, paint wear and other similar problems.

  20. Computerized thermal transient test console. [for nondestructive inspection of electroexplosive devices

    NASA Technical Reports Server (NTRS)

    Menichelli, V. J.

    1976-01-01

    A system for nondestructively testing electroexplosive devices by the thermal transient test technique is described. The signal, which is generated by pulsing the electroexplosive device bridgewire is reduced to digital form. The data is then interpreted by an appropriate program and the essential electrothermal parameters are resolved. The system is fast, eliminates arbitrary interpretation of the analog, and lends itself to production testing.

  1. Adaptive identification and interpretation of pressure transient tests of horizontal wells: challenges and perspectives

    NASA Astrophysics Data System (ADS)

    Sergeev, V. L.; Van Hoang, Dong

    2016-09-01

    The paper deals with a topical issue of defining oil reservoir properties during transient tests of horizontal wells equipped with information-measuring systems and reducing well downtime. The aim is to consider challenges and perspectives of developing models and algorithms for adaptive identification and interpretation of transient tests in horizontal wells with pressure buildup curve analysis. The models and algorithms should allow analyzing flow behavior, defining oil reservoir properties and determining well test completion time, as well as reducing well downtime. The present paper is based on the previous theoretical and practical findings in the spheres of transient well testing, systems analysis, system identification, function optimization and linear algebra. Field data and results of transient well tests with pressure buildup curve analysis have also been considered. The suggested models and algorithms for adaptive interpretation of transient tests conducted in horizontal wells with resulting pressure buildup curve make it possible to analyze flow behavior, as well as define the reservoir properties and determine well test completion time. The algorithms for adaptive interpretation are based on the integrated system of radial flow PBC models with time- dependent variables, account of additional a priori information and estimates of radial flow permeability. Optimization problems are solved with the case study of PBC interpretation for five horizontal wells of the Verkhnechonsk field.

  2. Final Report for TREAT Transient Overpower Tests R9 and R12 -- Part 2

    SciTech Connect

    Koopman, R. N.; Murphy, W. F.; Fink, C. L.; Kramer, N. A.; Stewart, R. R.

    1980-04-01

    Tests R9 and R12 were the first in-pile simulations of a 50c/s transient overpower (TOP) hypothetical core-disruptive accident (HCDA) as expected in the Fast Test Reactor (FTR). The tests employed prototypic thermal-hydraulic inlet and initial conditions, and used full-length FTR, fresh fuel pins. The initial conditions and power histories of tl1e two tests were prescribed alike to a point after the initial dbruptive pin failures. Test R9, the first of the two, provided data on the unterminated transient and was used to tailor the termination of test R12. Test R9 was allowed to continue on the overpower transient to the full energy capability of the Transient Test Reactor (TREAT) facility. This ensured failure of the test-bundle, but resulted in overpowering the test well beyond the predicted FTR response to the 50c/s HCDA TOP. Test R12, with the benefit of R9 transient data, was designed to scram TREAT just after the initial disruptive pin failures. Thereby, the response of test R12 was as close as possible to the actual FTR response to this HCDA as could be simulated in TREAT. Both R9 and R12 had objectives to examine the transient fuel motion due to the 50c/s TOP. Additional objectives were for R9 to examine fuel sweepout and for R12 to determine post-fuel relocation test section coolability. The results of the experiments demonstrated sweepout downstream of the active fuel zone: R9 - 50% and R12 - 5% of the total fuel inventory. Due to the excess input energy in test R9, the coolant channel was totally blocked in the region of the upper reflectors. Termination of the transient after the initial disruptive fuel pin failures in R12 resulted in less fuel motion, but allowed the coolant flow to return to 100% of full flow and quickly cool the test section. The termination of the R12 transient was accomplished by a flow meter signal feedback to the TREAT control computer. The test results indicate that: 1. The sweepout of fuel was dispersive and a coolable geometry

  3. A chassis test procedure to mimic the heavy-duty engine transient emissions certification test.

    PubMed

    Clark, N N; McKain, D L

    2001-03-01

    In-use emissions from vehicles using heavy-duty diesel engines can be significantly higher than the levels obtained during engine certification. These higher levels may be caused by a combination of degradation of engine components, poor engine maintenance, degradation or failure of emissions after-treatment devices, and engine and emissions system tampering. A direct comparison of in-use vehicle emissions with engine certification levels, however, is not possible without removing an engine from the vehicle in order to perform engine dynamometer emissions testing. The goal of this research was to develop a chassis test procedure that mimics the engine performance, and as such the expected emissions levels, from the engine certification emissions test prescribed in the U.S. Code of Federal Regulations. Emissions measurements were taken from two engines during testing on an engine dynamometer using the transient heavy-duty Federal Test Procedure (FTP). Additionally, each engine was installed in an appropriate vehicle, and emissions measurements were taken using a chassis dynamometer while employing a vehicle driving schedule intended to match closely the instantaneous torque and speed schedule of the engine FTP. Engine and chassis testing was performed with the engines in stock (unmodified) condition as well as in several modes to simulate either tampered or poorly maintained conditions. The use of a chassis test as a predictive tool for determining whether an engine in a vehicle would pass the engine certification test has proven to be worthwhile. Analysis of the data shows that identification of chassis-mounted engines with NOx emissions above certification levels is possible by employing engine-specific correction factors. In the case of PM emissions, significant data scatter allowed only the identification of gross PM emitters. Engine tampering and poor maintenance can raise PM and NOx emissions, and these increases can be correctly identified by a chassis test

  4. Transient getter scheme for the Tokamak Fusion Test Reactor

    SciTech Connect

    Cecchi, J.L.; Cohen, S.A.; Sredniawski, J.J.

    1980-01-01

    The ability of the Tokamak Fusion Test Reactor (TFTR) to attain the largest fusion power gain depends critically on minimizing plasma contamination and controlling the densities of the reacting deuterium and tritium. Experiments on a number of tokamaks have demonstrated that gettering over an appreciable surface area (greater than or equal to 10%) of the vacuum vessel greatly facilitates both of these objectives. One particular problem in implementing a surface pumping system in TFTR, however, is a restriction on the maximum allowable tritium content of the getter. This restriction could require regeneration of the absorbed tritium after as few as 50 machine pulses. We have developed a scheme utilizing SAES Zr/Al getter modules which obviates the need for such frequent interruptions of machine operation by taking advantage of the pulsed operation of TFTR. With the Zr/Al getter at temperatures between 500/sup 0/C to 600/sup 0/C it is possible to achieve a quasi-steady state in the tritium loading where the quantity of tritium desorbed between pulses is equal to the quantity which is absorbed during a pulse. Since frequent thermal cycling is not required, this scheme also reduces the possibility of Zr/Al getter material fatigue.

  5. Transient changes in thyroid functions tests after zoledronic acid infusion.

    PubMed

    Karga, Helen; Giagourta, Irene; Papaioannou, Garyphallia; Katsichti, Paraskevi; Pardalakis, Argyris; Kassi, Georgia; Zagoreou, Apostolia; Triantaphyllopoulou, Maria; Zerva, Cherry

    2011-01-01

    Zoledronic acid (ZA) induces an acute phase response in association with elevation of serum cytokines, which possibly alter the 3 types of iodothyronine deiodinase activity. We therefore studied the possible alteration in thyroid function tests by ZA. We investigated the acute changes in serum thyroid hormones, TSH, cortisol, white blood cells, CRP, interleukin-6 (IL-6) and tumor necrosis factor (TNF-α), before (0) and 1, 2 and 3 days after iv infusion of 5 mg ZA in 24 asymptomatic postmenopausal women with osteoporosis (ZA group) in comparison with a placebo group. In the majority of patients the ZA infusion was associated with acute phase response and fever within 24h after infusion which became attenuated on day three. Concurrently with increase in serum cortisol, CRP, IL-6 and TNF-α, on day 1 and 2, total serum T3 (TT3), free T3 (fT3), total T4 (TT4) and fT4 decreased with a nadir on day 2 in association with an increase in the fT4/fT3 ratio and reverse T3 (rT3) levels. All thyroid function changes returned to the baseline levels on day 3, with cytokines still at higher levels, although lower than those on day 2. Serum TSH remained essentially unchanged throughout the study. The changes in thyroid hormones were at least in part explained by the increased TNF-α, but not by IL-6. ZA induces short term changes in thyroid hormones, characteristic of nonthyroidal illness syndrome (NTIS), in association with an increase in TNF-α and IL-6.

  6. Method of Generating Transient Equivalent Sink and Test Target Temperatures for Swift BAT

    NASA Technical Reports Server (NTRS)

    Choi, Michael K.

    2004-01-01

    The NASA Swift mission has a 600-km altitude and a 22 degrees maximum inclination. The sun angle varies from 45 degrees to 180 degrees in normal operation. As a result, environmental heat fluxes absorbed by the Burst Alert Telescope (BAT) radiator and loop heat pipe (LHP) compensation chambers (CCs) vary transiently. Therefore the equivalent sink temperatures for the radiator and CCs varies transiently. In thermal performance verification testing in vacuum, the radiator and CCs radiated heat to sink targets. This paper presents an analytical technique for generating orbit transient equivalent sink temperatures and a technique for generating transient sink target temperatures for the radiator and LHP CCs. Using these techniques, transient target temperatures for the radiator and LHP CCs were generated for three thermal environmental cases: worst hot case, worst cold case, and cooldown and warmup between worst hot case in sunlight and worst cold case in the eclipse, and three different heat transport values: 128 W, 255 W, and 382 W. The 128 W case assumed that the two LHPs transport 255 W equally to the radiator. The 255 W case assumed that one LHP fails so that the remaining LHP transports all the waste heat from the detector array to the radiator. The 382 W case assumed that one LHP fails so that the remaining LHP transports all the waste heat from the detector array to the radiator, and has a 50% design margin. All these transient target temperatures were successfully implemented in the engineering test unit (ETU) LHP and flight LHP thermal performance verification tests in vacuum.

  7. Transient excitation and mechanical admittance test techniques for prediction of payload vibration environments

    NASA Technical Reports Server (NTRS)

    Kana, D. D.; Vargas, L. M.

    1977-01-01

    Transient excitation forces were applied separately to simple beam-and-mass launch vehicle and payload models to develop complex admittance functions for the interface and other appropriate points on the structures. These measured admittances were then analytically combined by a matrix representation to obtain a description of the coupled system dynamic characteristics. Response of the payload model to excitation of the launch vehicle model was predicted and compared with results measured on the combined models. These results are also compared with results of earlier work in which a similar procedure was employed except that steady-state sinusoidal excitation techniques were included. It is found that the method employing transient tests produces results that are better overall than the steady state methods. Furthermore, the transient method requires far less time to implement, and provides far better resolution in the data. However, the data acquisition and handling problem is more complex for this method. It is concluded that the transient test and admittance matrix prediction method can be a valuable tool for development of payload vibration tests.

  8. HEDL W-1 SLSF experiment LOPI transient and boiling test results. [LMFBR

    SciTech Connect

    Henderson, J.M.; Wood, S.A.; Rothrock, R.B.

    1980-01-01

    The W-1 Sodium Loop Safety Facility (SLSF) experiment was designed to study the heat release characteristics of fast reactor fuel pins under Loss-of-Piping-Integrity (LOPI) accident conditions and determine stable sodium boiling initiation and recovery limits in a prototypic fuel pin bundle array. The results of the experiment address major second level of assurance (LOA-2) safety issues and provide increased insight and understanding of phenomena that would inherently terminate hypothesized accidents with only limited core damage. The irradiation phase of the experiment, consisting of thirteen individual transients, was performed between May 27 and July 20, 1979. The final transient produced approximately two seconds of coolant boiling, cladding dryout, and incipient fuel pin failure. The facility and test hardware performed as designed, allowing completion of all planned tests and achievement of all test objectives.

  9. Pressure transient tests on geothermal wells in the Dogger aquifer, Paris Basin

    NASA Astrophysics Data System (ADS)

    giuglaris, elodie; hamm, virginie

    2014-05-01

    In this work, we propose a new interpretation of pressure transient tests conducted in more than sixty wells targeting the Dogger formation in the Paris basin. The most part of these wells were drilled during the eighties over a very short period of time in an urban area. The transient tests were only recorded during a pressure buildup and show that contrary to what has long been assumed the Dogger aquifer behavior is not homogeneous. The interpretation of the obtained data was mainly done with Horner's method, independently for each well, and assuming generally that the aquifer is homogeneous. Available data from pressure transient tests are limited because of the precision of the tools used, and because pressure buildup was only recorded during eight to twelve hours. The objective was to determine the average transmissivity and the skin factor in order to obtain the productivity of the wells. We gather all available data, including those obtained on the thirteen recent wells, and propose a new interpretation in terms of aquifer model. We use the pressure derivative method developed in the nineties for oil reservoirs which allows a better visualization of the model and of the heterogeneity of the aquifer. Most of the well tests have a derivative pressure curve with a slope equal to zero, that does not change after the well bore effects, confirming that the aquifer is relatively homogenous. However on a dozen of wells, data from pressure transient tests display singular behaviors that can be related to a double porosity or double permeability model for some wells and to a composite model for others. These observations question the validity of a homogeneous model for the Dogger aquifer in the Paris basin and the currently used parameters for the thermal and hydrodynamic predictive model of geothermal exploitation. Finally, this work increases our understanding of the Dogger aquifer in the Paris basin and will allow the optimization of the ongoing hydraulic tests and

  10. Proper Image Subtraction—Optimal Transient Detection, Photometry, and Hypothesis Testing

    NASA Astrophysics Data System (ADS)

    Zackay, Barak; Ofek, Eran O.; Gal-Yam, Avishay

    2016-10-01

    Transient detection and flux measurement via image subtraction stand at the base of time domain astronomy. Due to the varying seeing conditions, the image subtraction process is non-trivial, and existing solutions suffer from a variety of problems. Starting from basic statistical principles, we develop the optimal statistic for transient detection, flux measurement, and any image-difference hypothesis testing. We derive a closed-form statistic that: (1) is mathematically proven to be the optimal transient detection statistic in the limit of background-dominated noise, (2) is numerically stable, (3) for accurately registered, adequately sampled images, does not leave subtraction or deconvolution artifacts, (4) allows automatic transient detection to the theoretical sensitivity limit by providing credible detection significance, (5) has uncorrelated white noise, (6) is a sufficient statistic for any further statistical test on the difference image, and, in particular, allows us to distinguish particle hits and other image artifacts from real transients, (7) is symmetric to the exchange of the new and reference images, (8) is at least an order of magnitude faster to compute than some popular methods, and (9) is straightforward to implement. Furthermore, we present extensions of this method that make it resilient to registration errors, color-refraction errors, and any noise source that can be modeled. In addition, we show that the optimal way to prepare a reference image is the proper image coaddition presented in Zackay & Ofek. We demonstrate this method on simulated data and real observations from the PTF data release 2. We provide an implementation of this algorithm in MATLAB and Python.

  11. THEORETICAL ANALYSIS OF THE TRANSIENT PRESSURE RESPONSE FROM A CONSTANT FLOW RATE HYDRAULIC CONDUCTIVITY TEST.

    USGS Publications Warehouse

    Morin, Roger H.; Olsen, Harold W.

    1987-01-01

    Incorporating a flow pump into a conventional triaxial laboratory system allows fluid to be supplied to or withdrawn from the base of a sediment sample at small and constant rates. An initial transient record of hydraulic head versus time is observed which eventually stabilizes to a constant steady state gradient across the sample; values of hydraulic conductivity can subsequently be determined from Darcy's law. In this paper, analytical methods are presented for determining values of specific storage and hydraulic conductivity from the initial transient phase of such a constant flow rate test. These methods are based on a diffusion equation involving pore pressure and are analogous to those used to describe the soil consolidation process and also to interpret aquifer properties from pumping tests.

  12. Compilation of Quality Assurance Documentation for Analyses Performed for the Resumption of Transient Testing Environmental Assessment

    SciTech Connect

    Annette L. Schafer; A. Jeffrey Sondrup

    2013-11-01

    This is a companion document to the analyses performed in support of the environmental assessment for the Resumption of Transient Fuels and Materials Testing. It is provided to allow transparency of the supporting calculations. It provides computer code input and output. The basis for the calculations is documented separately in INL (2013) and is referenced, as appropriate. Spreadsheets used to manipulate the code output are not provided.

  13. Testing and analysis of structural integrity of electrosleeved tubes under severe accident transients

    SciTech Connect

    Majumdar, S.

    1999-12-10

    The structural integrity of flawed steam generator tubing with Electrosleeves{trademark} under simulated severe accident transients was analyzed by analytical models that used available material properties data and results from high-temperature tests conducted on Electrosleeved tubes. The Electrosleeve material is almost pure Ni and derives its strength and other useful properties from its nanocrystalline microstructure, which is stable at reactor operating temperatures. However, it undergoes rapid grain growth, at the high temperatures expected during severe accidents, resulting in a loss of strength and a corresponding decrease in flow stress. The magnitude of this decrease depends on the time-temperature history during the accident. Failure tests were conducted at ANL and FTI on internally pressurized Electrosleeved tubes with 80% and 100% throughwall machined axial notches in tie parent tubes that were subjected to simulated severe accident temperature transients. The test results, together with the analytical model, were used to estimate the unaged flow stress curve of the Electrosleeved material at high temperatures. Failure temperatures for Electrosleeved tubes with throughwall and part-throughwall axial cracks of various lengths in the parent tubes were calculated for a postulated severe accident transient.

  14. Testing the ontogenetic base for the transient model of inflorescence development

    PubMed Central

    Bull-Hereñu, Kester; Claßen-Bockhoff, Regine

    2013-01-01

    Backgrounds and Aims Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the ‘transient model’ successful in explaining some types of inflorescence architectures based on two main principles: the decline of the so called ‘vegetativeness’ (veg) factor and the transient nature of apical meristems in developing inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in inflorescence development. Methods To test the ontogenetic base of veg decline and the transient character of apical meristems the ontogeny of meristematic size in developing inflorescences was investigated under scanning electron microscopy. Early and late inflorescence meristems were measured and compared during inflorescence development in 13 eudicot species from 11 families. Key Results The initial size of the inflorescence meristem in closed inflorescences correlates with the number of nodes in the mature inflorescence. Conjunct compound inflorescences (panicles) show a constant decrease of meristematic size from early to late inflorescence meristems, while disjunct compound inflorescences present an enlargement by merging from early inflorescence meristems to late inflorescence meristems, implying a qualitative change of the apical meristems during ontogeny. Conclusions Partial confirmation was found for the transient model for inflorescence architecture in the ontogeny: the initial size of the apical meristem in closed inflorescences is consistent with the postulated veg decline mechanism regulating the size of the inflorescence. However, the observed biphasic kinetics of the development of the apical meristem in compound racemes offers the primary explanation for their disjunct morphology, contrary to the putative exclusive transient mechanism in lateral axes as expected by the model. PMID:23425784

  15. Nonlinear transient wave excitation as a new tool in model testing

    SciTech Connect

    Clauss, G.F.; Kuehnlein, W.L.

    1996-12-31

    Short extension transient waves with tailor-made spectra are extremely efficient for model testing. For small water elevations a linear description of the wave field is satisfactory. With higher transient wave trains, however, the linear description becomes increasingly inaccurate, and a new numerical technique must be developed. Such a new method is based on the fact that short and high wave groups with strong nonlinear characteristics evolve from long and low wave groups, which are characterized by linear principles. As the total energy of the transient wave is invariant during its metamorphosis, the initial linear Fourier spectrum is selected as the backbone of wave information or as the primordial cell from which all nonlinearities are hatched. Based on the initial Fourier spectrum which is the core of the wave information operator the shape variation of the linear transient wave train during propagation is calculated. At selected positions the nonlinear expansion is accomplished by solving the mutually dependent particle motion equations in time domain. The proposed new method uses a numerical nonlinear description of transient wave trains as a function of time or space for any fixed or moving reference point. At its primordial state it is based on a linear superposition of wave information which is complemented by an expanded velocity potential to calculate nonlinear surface elevations, particle motions, velocities, and accelerations. After the nonlinear wave trains converge and pass the concentration point only to diverge and fade away as long, low and linear wave groups, the primordial linear Fourier spectrum can be found again at the end of the development. This step can be used to monitor the transformation. Wave energy spectra and the shape of the wave train can be designed with special regard to the proposed task. Based on these data the entire wave field can be determined.

  16. Transient Pressure Test Article (TPTA) 1.1 and 1.1A, volume 1

    NASA Technical Reports Server (NTRS)

    Rebells, Clarence A.

    1988-01-01

    This final test report presents the results obtained during the static hot firing and cold-gas high Q tests of the first Transient Pressure Test Article (TPTA) 1.1. The TPTA consisted of field test joints A and B, which were the original RSRM J-insulation configuration, with a metal capture feature. It also consisted of a flight configuration nozzle-to-case test joint (Joint D) with shorter vent slots. Fluorocarbon O-rings were used in all the test joints. The purpose of the TPTA tests is to evaluate and characterize the RSMR field and nozzle-to-case joints under the influence of ignition and strut loads during liftoff anf high Q. All objectives of the cold-gas high Q (TPTA 1.1A) test were met and all measurements were close to predicted values. During the static hot-firing test (TPTA 1.1), the motor was inadvertently plugged by the quench injector plug, making it a more severe test, although no strut loads were applied. The motor was depressurized after approximately 11 min using an auxiliary system, and no anomalies were noted. In the static hot-firing test, pressure was incident on the insulation and the test joint gaps were within the predicted range. During the static hot-firing test, no strut loads were applied because the loading system malfunctioned. For this test, all measurements were within range of similar tests performed without strut loads.

  17. Transient Thermal Testing and Analysis of a Thermally Insulating Structural Sandwich Panel

    NASA Technical Reports Server (NTRS)

    Blosser, Max L.; Daryabeigi, Kamran; Bird, Richard K.; Knutson, Jeffrey R.

    2015-01-01

    A core configuration was devised for a thermally insulating structural sandwich panel. Two titanium prototype panels were constructed to illustrate the proposed sandwich panel geometry. The core of one of the titanium panels was filled with Saffil(trademark) alumina fibrous insulation and the panel was tested in a series of transient thermal tests. Finite element analysis was used to predict the thermal response of the panel using one- and two-dimensional models. Excellent agreement was obtained between predicted and measured temperature histories.

  18. Evaluation of naturally fractured gas shale production utilizing multiwell transient tests: A field study

    SciTech Connect

    Chen, C.C.; Alam, J.; Blanton, T.L.; Vozniak, J.P.

    1984-05-01

    A series of multiple well transient tests were conducted in a Devonian shale gas field in Meigs County, Ohio. Production parameters were quantified and it was determined that the reservoir is highly anisotropic, which is a significant factor in calculating half-fracture length from pressure transient data. Three stimulation treatments, including conventional explosive shooting, nitrogen foam frac, and high energy gas frac (HEGF), were compared on the basis of overall effectiveness and performance. Based on the evaluation of results, the nitrogen foam frac provided the most improved productivity. The study provided new type curves and analytical solutions for the mathematical representation of naturally fractured reservoirs and confirmed that the shale reservoir in Meigs County can be modeled as a dual porosity system using pseudosteady-state gas transfer from the matrix to the fracture system.

  19. Evaluation of the Transient Hydrologic Source Term for the Cambric Underground Nuclear Test at Frenchman Flat, Nevada test Site

    SciTech Connect

    Carle, S F; Maxwell, R M; Pawloski, G A; Shumaker, D E; Tompson, A B; Zavarin, M

    2006-12-12

    The objective of Phase II HST work is to develop a better understanding of the evolution of the HST for 1,000 years at the CAMBRIC underground nuclear test site in Frenchman Flat at the NTS. This work provides a better understanding of activities as they actually occurred, incorporates improvements based on recent data acquisition, and provides a basis to use the CAMBRIC site for model validation and monitoring activities as required by the UGTA Project. CAMBRIC was the only test in Frenchman Flat detonated under the water table and best represents a fully saturated environment. These simulations are part of a broad Phase II Frenchman Flat Corrective Action Unit (CAU) flow and transport modeling effort being conducted by the Department of Energy (DOE) Underground Test Area (UGTA) Project. HST simulations provide, either directly or indirectly, the source term used in the CAU model to calculate a contaminant boundary. Work described in this report augments Phase I HST calculations at CAMBRIC conducted by Tompson et al. (1999) and Pawloski et al. (2001). Phase II HST calculations have been organized to calculate source terms under two scenarios: (1) A representation of the transient flow and radionuclide release behavior at the CAMBRIC site that is more specific than Tompson et al. (1999). This model reflects the influence of the background hydraulic gradient, residual test heat, pumping experiment, and ditch recharge, and takes into account improved data sources and modeling approaches developed since the previous efforts. Collectively, this approach will be referred to as the transient CAMBRIC source term. This report describes the development of the transient CAMBRIC HST. (2) A generic release model made under steady-state flow conditions, in the absence of any transient effects, at the same site with the same radiologic source term. This model is for use in the development of simpler release models for the other nine underground test sites in the Frenchman Flat

  20. Predicting the Reliability of Brittle Material Structures Subjected to Transient Proof Test and Service Loading

    NASA Astrophysics Data System (ADS)

    Nemeth, Noel N.; Jadaan, Osama M.; Palfi, Tamas; Baker, Eric H.

    Brittle materials today are being used, or considered, for a wide variety of high tech applications that operate in harsh environments, including static and rotating turbine parts, thermal protection systems, dental prosthetics, fuel cells, oxygen transport membranes, radomes, and MEMS. Designing brittle material components to sustain repeated load without fracturing while using the minimum amount of material requires the use of a probabilistic design methodology. The NASA CARES/Life 1 (Ceramic Analysis and Reliability Evaluation of Structure/Life) code provides a general-purpose analysis tool that predicts the probability of failure of a ceramic component as a function of its time in service. This capability includes predicting the time-dependent failure probability of ceramic components against catastrophic rupture when subjected to transient thermomechanical loads (including cyclic loads). The developed methodology allows for changes in material response that can occur with temperature or time (i.e. changing fatigue and Weibull parameters with temperature or time). For this article an overview of the transient reliability methodology and how this methodology is extended to account for proof testing is described. The CARES/Life code has been modified to have the ability to interface with commercially available finite element analysis (FEA) codes executed for transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

  1. Preliminary Analysis of the Transient Reactor Test Facility (TREAT) with PROTEUS

    SciTech Connect

    Connaway, H. M.; Lee, C. H.

    2015-11-30

    The neutron transport code PROTEUS has been used to perform preliminary simulations of the Transient Reactor Test Facility (TREAT). TREAT is an experimental reactor designed for the testing of nuclear fuels and other materials under transient conditions. It operated from 1959 to 1994, when it was placed on non-operational standby. The restart of TREAT to support the U.S. Department of Energy’s resumption of transient testing is currently underway. Both single assembly and assembly-homogenized full core models have been evaluated. Simulations were performed using a historic set of WIMS-ANL-generated cross-sections as well as a new set of Serpent-generated cross-sections. To support this work, further analyses were also performed using additional codes in order to investigate particular aspects of TREAT modeling. DIF3D and the Monte-Carlo codes MCNP and Serpent were utilized in these studies. MCNP and Serpent were used to evaluate the effect of geometry homogenization on the simulation results and to support code-to-code comparisons. New meshes for the PROTEUS simulations were created using the CUBIT toolkit, with additional meshes generated via conversion of selected DIF3D models to support code-to-code verifications. All current analyses have focused on code-to-code verifications, with additional verification and validation studies planned. The analysis of TREAT with PROTEUS-SN is an ongoing project. This report documents the studies that have been performed thus far, and highlights key challenges to address in future work.

  2. Parameter estimation and tests of General Relativity with GW transients in Advanced LIGO

    NASA Astrophysics Data System (ADS)

    Vitale, Salvatore

    2016-03-01

    The Advanced LIGO observatories have successfully completed their first observation run. Data were collected from September 2015 to January 2016, with a sensitivity a few times better than initial instruments in the hundreds of Hertz band. Bayesian parameter estimation and model selection algorithms can be used to estimate the astrophysical parameters of gravitational-wave sources, as well as to perform tests of General Relativity in its strong-field dynamical regime. In this talk we will describe the methods devised to characterize transient gravitational wave sources and their applications in the advanced gravitational-wave detector era.

  3. Large transient fault current test of an electrical roll ring. [for Space Station Freedom

    NASA Technical Reports Server (NTRS)

    Yenni, Edward J.; Birchenough, Arthur G.

    1991-01-01

    The Space Station Freedom uses precision rotary gimbals to provide for sun tracking of its photoelectric arrays. Electrical power, command signals, and data are transferred across the gimbals by roll rings. Roll rings have been shown to be capable of highly efficient electrical transmission and long life, through tests conducted at the NASA Lewis Research Center and Honeywell's Satellite and Space Systems Division in Phoenix, AZ. Large potential fault currents inherent to the power system's DC distribution architecture have brought about the need to evaluate the effects of large transient fault currents on roll rings. A test recently conducted at Lewis subjected a roll ring to a simulated worst case space station electrical fault. The system model used to obtain the fault profile is described, along with details of the reduced order circuit that was used to simulate the fault. Test results comparing roll ring performance before and after the fault are also presented.

  4. Theoretical Evaluation of the Transient Response of Constant Head and Constant Flow-Rate Permeability Tests

    USGS Publications Warehouse

    Zhang, M.; Takahashi, M.; Morin, R.H.; Esaki, T.

    1998-01-01

    A theoretical analysis is presented that compares the response characteristics of the constant head and the constant flowrate (flow pump) laboratory techniques for quantifying the hydraulic properties of geologic materials having permeabilities less than 10-10 m/s. Rigorous analytical solutions that describe the transient distributions of hydraulic gradient within a specimen are developed, and equations are derived for each method. Expressions simulating the inflow and outflow rates across the specimen boundaries during a constant-head permeability test are also presented. These solutions illustrate the advantages and disadvantages of each method, including insights into measurement accuracy and the validity of using Darcy's law under certain conditions. The resulting observations offer practical considerations in the selection of an appropriate laboratory test method for the reliable measurement of permeability in low-permeability geologic materials.

  5. Use of ruthenium dyes for subnanosecond detector fidelity testing in real time transient absorption

    SciTech Connect

    Byrdin, Martin; Thiagarajan, Viruthachalam; Villette, Sandrine; Espagne, Agathe; Brettel, Klaus

    2009-04-15

    Transient absorption spectroscopy is a powerful tool for the study of photoreactions on time scales from femtoseconds to seconds. Typically, reactions slower than {approx}1 ns are recorded by the ''classical'' technique; the reaction is triggered by an excitation flash, and absorption changes accompanying the reaction are recorded in real time using a continuous monitoring light beam and a detection system with sufficiently fast response. The pico- and femtosecond region can be accessed by the more recent ''pump-probe'' technique, which circumvents the difficulties of real time detection on a subnanosecond time scale. This is paid for by accumulation of an excessively large number of shots to sample the reaction kinetics. Hence, it is of interest to extend the classical real time technique as far as possible to the subnanosecond range. In order to identify and minimize detection artifacts common on a subnanosecond scale, like overshoot, ringing, and signal reflections, rigorous testing is required of how the detection system responds to fast changes of the monitoring light intensity. Here, we introduce a novel method to create standard signals for detector fidelity testing on a time scale from a few picoseconds to tens of nanoseconds. The signals result from polarized measurements of absorption changes upon excitation of ruthenium complexes {l_brace}[Ru(bpy){sub 3}]{sup 2+} and a less symmetric derivative{r_brace} by a short laser flash. Two types of signals can be created depending on the polarization of the monitoring light with respect to that of the excitation flash: a fast steplike bleaching at magic angle and a monoexponentially decaying bleaching for parallel polarizations. The lifetime of the decay can be easily varied via temperature and viscosity of the solvent. The method is applied to test the performance of a newly developed real time transient absorption setup with 300 ps time resolution and high sensitivity.

  6. Reactivity Initiated Accident Simulation to Inform Transient Testing of Candidate Advanced Cladding

    SciTech Connect

    Brown, Nicholas R; Wysocki, Aaron J; Terrani, Kurt A

    2016-01-01

    Abstract. Advanced cladding materials with potentially enhanced accident tolerance will yield different light water reactor performance and safety characteristics than the present zirconium-based cladding alloys. These differences are due to different cladding material properties and responses to the transient, and to some extent, reactor physics, thermal, and hydraulic characteristics. Some of the differences in reactors physics characteristics will be driven by the fundamental properties (e.g., absorption in iron for an iron-based cladding) and others will be driven by design modifications necessitated by the candidate cladding materials (e.g., a larger fuel pellet to compensate for parasitic absorption). Potential changes in thermal hydraulic limits after transition from the current zirconium-based cladding to the advanced materials will also affect the transient response of the integral fuel. This paper leverages three-dimensional reactor core simulation capabilities to inform on appropriate experimental test conditions for candidate advanced cladding materials in a control rod ejection event. These test conditions are using three-dimensional nodal kinetics simulations of a reactivity initiated accident (RIA) in a representative state-of-the-art pressurized water reactor with both nuclear-grade iron-chromium-aluminum (FeCrAl) and silicon carbide based (SiC-SiC) cladding materials. The effort yields boundary conditions for experimental mechanical tests, specifically peak cladding strain during the power pulse following the rod ejection. The impact of candidate cladding materials on the reactor kinetics behavior of RIA progression versus reference zirconium cladding is predominantly due to differences in: (1) fuel mass/volume/specific power density, (2) spectral effects due to parasitic neutron absorption, (3) control rod worth due to hardened (or softened) spectrum, and (4) initial conditions due to power peaking and neutron transport cross sections in the

  7. Improving referrals for tilt table testing in patients with transient loss of consciousness.

    PubMed

    Thornton, Luke; Rahunathan, Nithusa; Verma, Narain; Wong, Kenneth

    2016-01-01

    Tilt table testing has been used for over twenty years in the investigation of patients with transient loss of consciousness. The European Society of Cardiology (ESC) recently recommended new guidance regarding indications for tilt table testing. We conducted an educational intervention and produced a new referral proforma that referring clinicians are expected to fill in for all patients referred for tilt table testing. At baseline, 76% (n=84) of referrals for tilt table testing were made in accordance to ESC guidance. Following a simple educational intervention, 100% (n=6) were in line with ESC guidance. After the introduction of the referral proforma, 92% (n=12) of referrals followed ESC guidance. At final data collection, 100% (n=11) of referrals followed ESC guidance. In conclusion, a simple educational intervention and the use of a referral proforma in this quality improvement project have made a sustained difference in improving the appropriateness of referrals for tilt table testing. This has the potential to optimise the efficient use of resources and improve patient care through avoiding unnecessary investigation.

  8. Improving referrals for tilt table testing in patients with transient loss of consciousness

    PubMed Central

    Thornton, Luke; Rahunathan, Nithusa; Verma, Narain; Wong, Kenneth

    2016-01-01

    Tilt table testing has been used for over twenty years in the investigation of patients with transient loss of consciousness. The European Society of Cardiology (ESC) recently recommended new guidance regarding indications for tilt table testing. We conducted an educational intervention and produced a new referral proforma that referring clinicians are expected to fill in for all patients referred for tilt table testing. At baseline, 76% (n=84) of referrals for tilt table testing were made in accordance to ESC guidance. Following a simple educational intervention, 100% (n=6) were in line with ESC guidance. After the introduction of the referral proforma, 92% (n=12) of referrals followed ESC guidance. At final data collection, 100% (n=11) of referrals followed ESC guidance. In conclusion, a simple educational intervention and the use of a referral proforma in this quality improvement project have made a sustained difference in improving the appropriateness of referrals for tilt table testing. This has the potential to optimise the efficient use of resources and improve patient care through avoiding unnecessary investigation. PMID:27096093

  9. Transient Plume Model Testing Using LADEE Spacecraft Attitude Control System Operations

    SciTech Connect

    Woronowicz, M. S.

    2011-05-20

    The Lunar Atmosphere Dust Environment Explorer (LADEE) spacecraft is being designed for a mission featuring low altitude orbits of the Moon to take relevant ambient measurements before that environment becomes altered by future exploration activities. Instruments include a neutral mass spectrometer capable of measuring ambient species density levels below 100 molecules/cm{sup 3}. Coincidentally, with a favorable combination of spacecraft orientations, it is also possible to measure plume gases from LADEE attitude control system thruster operations as they are reflected from the daytime lunar surface and subsequently intercepted by the spacecraft as it orbits overhead. Under such circumstances, it may be possible to test a variety of properties and assumptions associated with various transient plume models or to infer certain aspects regarding lunar surface properties.

  10. Measuring the Optical Performance of Evacuated Receivers via an Outdoor Thermal Transient Test: Preprint

    SciTech Connect

    Kutscher, C.; Burkholder, F.; Netter, J.

    2011-08-01

    Modern parabolic trough solar collectors operated at high temperatures to provide the heat input to Rankine steam power cycles employ evacuated receiver tubes along the collector focal line. High performance is achieved via the use of a selective surface with a high absorptance for incoming short-wave solar radiation and a low emittance for outgoing long-wave infrared radiation, as well as the use of a hard vacuum to essentially eliminate convective and conductive heat losses. This paper describes a new method that determines receiver overall optical efficiency by exposing a fluid-filled, pre-cooled receiver to one sun outdoors and measuring the slope of the temperature curve at the point where the receiver temperature passes the glass envelope temperature (that is, the point at which there is no heat gain or loss from the absorber). This transient test method offers the potential advantages of simplicity, high accuracy, and the use of the actual solar spectrum.

  11. Heat and Mass Transfer Analysis of Dehumidifiers Using Adiabatic Transient Tests

    SciTech Connect

    Maclaine-Cross, I. L.; Pesaran, A. A.

    1986-04-01

    Adiabatic step transient data were obtained for two dehumidifier test matrices, using parallel plates with crushed silica gel and staggered parallel strips coated with microbead silica gel. The data were analyzed using the statistical moments method and combined heat and mass transfer analogy theory. The analysis showed that the average overall Nusselt number in both matrices was about 40% to 50% lower than laminar flow predictions. The average overall Nusselt number for the microbead staggered matrix was about 85% larger than that of the crushed silica-gel parallel-plate matrix. The Nusselt number/friction factor Reynolds number ratio (Nu/fRe) of the microbead, staggered parallel-strip matrix was about 28% larger than that of the crushed silica-gel parallel-plate matrix. These results were explained by the presence of a stagnant gas film. The results showed that compact, high-performance, rotary dehumidifiers for desiccant cooling systems are possible and economical.

  12. Transient Plume Model Testing Using LADEE Spacecraft Attitude Control System Operations

    NASA Technical Reports Server (NTRS)

    Woronowicz, M. S.

    2010-01-01

    The Lunar Atmosphere Dust Environment Explorer (LADEE) spacecraft is being designed for a mission featuring low altitude orbits of the Moon to take relevant ambient measurements before that environment becomes altered by future exploration activities. Instruments include a neutral mass spectrometer capable of measuring ambient species density levels below 100 molecules/cu cm. Coincidentally, with a favorable combination of spacecraft orientations, it is also possible to measure plume gases from LADEE attitude control system thruster operations as they are reflected from the daytime lunar surface and subsequently intercepted by the spacecraft as it orbits overhead. Under such circumstances, it may be possible to test a variety of properties and assumptions associated with various transient plume models or to infer certain aspects regarding lunar surface properties.

  13. Barometric pressure transient testing applications at the Nevada Test Site. Nuclear chimney analysis. Final report

    SciTech Connect

    Hanson, J.M.

    1985-12-01

    Investigations of barometric pressure testing of NTS nuclear chimneys were reviewed. This review includes the models used in the interpretation, methods of analysis, and results. Analytic and semi-analytic models were presented and applied to both historical data and new data taken for this current project. An interpretation technique based on non-linear least squares methods was used to analyze this data in terms of historic and more recent chimney models. Finally, a detailed discussion of radioactive gas transport due to surface barometric pressure fluctuations was presented. This mechanism of transport, referred to as ''barometric pumping,'' is presented in terms of conditions likely to be encountered at the NTS. The report concludes with a discussion of the current understanding of gas flow properties in the alluvial and volcanic areas of the NTS, and suggestions for future efforts directed toward increasing this understanding are presented.

  14. Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program

    SciTech Connect

    Annette L. Schafer; Lloyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner

    2013-11-01

    Environmental and health impacts are presented for activities associated with transient testing of nuclear fuel and material using two candidate test reactors. Transient testing involves irradiation of nuclear fuel or materials for short time-periods under high neutron flux rates. The transient testing process includes transportation of nuclear fuel or materials inside a robust shipping cask to a hot cell, removal from the shipping cask, pre-irradiation examination of the nuclear materials, assembly of an experiment assembly, transportation of the experiment assembly to the test reactor, irradiation in the test reactor, transport back to the hot cell, and post-irradiation examination of the nuclear fuel or material. The potential for environmental or health consequences during the transportation, examination, and irradiation actions are assessed for normal operations, off-normal (accident) scenarios, and transportation. Impacts to the environment (air, soil, and groundwater), are assessed during each phase of the transient testing process. This report documents the evaluation of potential consequences to the general public. This document supports the Environmental Assessment (EA) required by the U.S. National Environmental Policy Act (NEPA) (42 USC Subsection 4321 et seq.).

  15. Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program

    SciTech Connect

    Annette L. Schafer; LLoyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner

    2014-02-01

    This document contains the analysis details and summary of analyses conducted to evaluate the environmental impacts for the Resumption of Transient Fuel and Materials Testing Program. It provides an assessment of the impacts for the two action alternatives being evaluated in the environmental assessment. These alternatives are (1) resumption of transient testing using the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) and (2) conducting transient testing using the Annular Core Research Reactor (ACRR) at Sandia National Laboratory in New Mexico (SNL/NM). Analyses are provided for radiologic emissions, other air emissions, soil contamination, and groundwater contamination that could occur (1) during normal operations, (2) as a result of accidents in one of the facilities, and (3) during transport. It does not include an assessment of the biotic, cultural resources, waste generation, or other impacts that could result from the resumption of transient testing. Analyses were conducted by technical professionals at INL and SNL/NM as noted throughout this report. The analyses are based on bounding radionuclide inventories, with the same inventories used for test materials by both alternatives and different inventories for the TREAT Reactor and ACRR. An upper value on the number of tests was assumed, with a test frequency determined by the realistic turn-around times required between experiments. The estimates provided for impacts during normal operations are based on historical emission rates and projected usage rates; therefore, they are bounding. Estimated doses for members of the public, collocated workers, and facility workers that could be incurred as a result of an accident are very conservative. They do not credit safety systems or administrative procedures (such as evacuation plans or use of personal protective equipment) that could be used to limit worker doses. Doses estimated for transportation are conservative and are based on

  16. Single-Event Transient Testing of the Crane Aerospace and Electronics SMHF2812D Dual DC-DC Converter

    NASA Technical Reports Server (NTRS)

    Casey, Megan

    2015-01-01

    The purpose of this testing was to characterize the Crane Aerospace & Electronics (Crane) Interpoint SMHF2812D for single-event transient (SET) susceptibility. These data shall be used for flight lot evaluation, as well as qualification by similarity of the SMHF family of converters, all of which use the same active components.

  17. Cosmic Transients Test Einstein's Equivalence Principle out to GeV Energies

    NASA Astrophysics Data System (ADS)

    Gao, He; Wu, Xue-Feng; Mészáros, Peter

    2015-09-01

    The Einstein Equivalence Principle (EEP) can be probed with astrophysical sources emitting simultaneously different types of neutral particles, or particles with varying energies, by testing their time of flight through the same gravitational field. Here we use the time delays between correlated photons from cosmological transients to constrain the accuracy of the EEP. We take data from two gamma-ray bursts as an example and, as a lower limit to the theoretical time delays between different energies, we use delays arising from only the gravitational field of our own galaxy. We then show that the parameterized post-Newtonian parameter γ is the same for photons over energy ranges between eV and MeV and between MeV and GeV to a part in 10-7, which is at least one order of magnitude better than previous limits. Combining this bound on the wavelength dependence of γ with the absolute bound | γ -1| \\lt 0.3% from light-deflection measurements at optical (eV) wavelengths, we thus extend this absolute bound on γ to GeV energies.

  18. Transient and Steady-state Tests of the Space Power Research Engine with Resistive and Motor Loads

    NASA Technical Reports Server (NTRS)

    Rauch, Jeffrey S.; Kankam, M. David

    1995-01-01

    The NASA Lewis Research Center (LeRC) has been testing free-piston Stirling engine/linear alternators (FPSE/LA) to develop advanced power convertors for space-based electrical power generation. Tests reported herein were performed to evaluate the interaction and transient behavior of FPSE/LA-based power systems with typical user loads. Both resistive and small induction motor loads were tested with the space power research engine (SPRE) power system. Tests showed that the control system could maintain constant long term voltage and stable periodic operation over a large range of engine operating parameters and loads. Modest resistive load changes were shown to cause relatively large voltage and, therefore, piston and displacer amplitude excursions. Starting a typical small induction motor was shown to cause large and, in some cases, deleterious voltage transients. The tests identified the need for more effective controls, if FPSE/LAs are to be used for stand-alone power systems. The tests also generated a large body of transient dynamic data useful for analysis code validation.

  19. Evaluation of the Non-Transient Hydrologic Source Term from the CAMBRIC Underground Nuclear Test in Frenchman Flat, Nevada Test Site

    SciTech Connect

    Tompson, A B; Maxwell, R M; Carle, S F; Zavarin, M; Pawloski, G A; Shumaker, D E

    2005-08-05

    Hydrologic Source Term (HST) calculations completed in 1998 at the CAMBRIC underground nuclear test site were LLNL's first attempt to simulate a hydrologic source term at the NTS by linking groundwater flow and transport modeling with geochemical modeling (Tompson et al., 1999). Significant effort was applied to develop a framework that modeled in detail the flow regime and captured all appropriate chemical processes that occurred over time. However, portions of the calculations were simplified because of data limitations and a perceived need for generalization of the results. For example: (1) Transient effects arising from a 16 years of pumping at the site for a radionuclide migration study were not incorporated. (2) Radionuclide fluxes across the water table, as derived from infiltration from a ditch to which pumping effluent was discharged, were not addressed. (3) Hydrothermal effects arising from residual heat of the test were not considered. (4) Background data on the ambient groundwater flow direction were uncertain and not represented. (5) Unclassified information on the Radiologic Source Term (RST) inventory, as tabulated recently by Bowen et al. (2001), was unavailable; instead, only a limited set of derived data were available (see Tompson et al., 1999). (6) Only a small number of radionuclides and geochemical reactions were incorporated in the work. (7) Data and interpretation of the RNM-2S multiple well aquifer test (MWAT) were not available. As a result, the current Transient CAMBRIC Hydrologic Source Term project was initiated as part of a broader Phase 2 Frenchman Flat CAU flow and transport modeling effort. The source term will be calculated under two scenarios: (1) A more specific representation of the transient flow and radionuclide release behavior at the site, reflecting the influence of the background hydraulic gradient, residual test heat, pumping experiment, and ditch recharge, and taking into account improved data sources and modeling

  20. Transient Hypothyroidism after Radioiodine for Graves’ Disease: Challenges in Interpreting Thyroid Function Tests

    PubMed Central

    Sheehan, Michael T.; Doi, Suhail A.R.

    2016-01-01

    Graves’ disease is the most common cause of hyperthyroidism and is often managed with radioactive iodine (RAI) therapy. With current dosing schemes, the vast majority of patients develop permanent post-RAI hypothyroidism and are placed on life-long levothyroxine therapy. This hypothyroidism typically occurs within the first 3 to 6 months after RAI therapy is administered. Indeed, patients are typically told to expect life-long thyroid hormone replacement therapy to be required within this timeframe and many providers expect this post-RAI hypothyroidism to be complete and permanent. There is, however, a small subset of patients in whom a transient post-RAI hypothyroidism develops which, initially, presents exactly as the typical permanent hypothyroidism. In some cases the transient hypothyroidism leads to a period of euthyroidism of variable duration eventually progressing to permanent hypothyroidism. In others, persistent hyperthyroidism requires a second dose of RAI. Failure to appreciate and recognize the possibility of transient post-RAI hypothyroidism can delay optimal and appropriate treatment of the patient. We herein describe five cases of transient post-RAI hypothyroidism which highlight this unusual sequence of events. Increased awareness of this possible outcome after RAI for Graves’ disease will help in the timely management of patients. PMID:26864507

  1. Transient Hypothyroidism after Radioiodine for Graves' Disease: Challenges in Interpreting Thyroid Function Tests.

    PubMed

    Sheehan, Michael T; Doi, Suhail A R

    2016-03-01

    Graves' disease is the most common cause of hyperthyroidism and is often managed with radioactive iodine (RAI) therapy. With current dosing schemes, the vast majority of patients develop permanent post-RAI hypothyroidism and are placed on life-long levothyroxine therapy. This hypothyroidism typically occurs within the first 3 to 6 months after RAI therapy is administered. Indeed, patients are typically told to expect life-long thyroid hormone replacement therapy to be required within this timeframe and many providers expect this post-RAI hypothyroidism to be complete and permanent. There is, however, a small subset of patients in whom a transient post-RAI hypothyroidism develops which, initially, presents exactly as the typical permanent hypothyroidism. In some cases the transient hypothyroidism leads to a period of euthyroidism of variable duration eventually progressing to permanent hypothyroidism. In others, persistent hyperthyroidism requires a second dose of RAI. Failure to appreciate and recognize the possibility of transient post-RAI hypothyroidism can delay optimal and appropriate treatment of the patient. We herein describe five cases of transient post-RAI hypothyroidism which highlight this unusual sequence of events. Increased awareness of this possible outcome after RAI for Graves' disease will help in the timely management of patients. PMID:26864507

  2. Global nuclear energy partnership fuels transient testing at the Sandia National Laboratories nuclear facilities : planning and facility infrastructure options.

    SciTech Connect

    Kelly, John E.; Wright, Steven Alan; Tikare, Veena; MacLean, Heather J.; Parma, Edward J., Jr.; Peters, Curtis D.; Vernon, Milton E.; Pickard, Paul S.

    2007-10-01

    The Global Nuclear Energy Partnership fuels development program is currently developing metallic, oxide, and nitride fuel forms as candidate fuels for an Advanced Burner Reactor. The Advance Burner Reactor is being designed to fission actinides efficiently, thereby reducing the long-term storage requirements for spent fuel repositories. Small fuel samples are being fabricated and evaluated with different transuranic loadings and with extensive burnup using the Advanced Test Reactor. During the next several years, numerous fuel samples will be fabricated, evaluated, and tested, with the eventual goal of developing a transmuter fuel database that supports the down selection to the most suitable fuel type. To provide a comparative database of safety margins for the range of potential transmuter fuels, this report describes a plan to conduct a set of early transient tests in the Annular Core Research Reactor at Sandia National Laboratories. The Annular Core Research Reactor is uniquely qualified to perform these types of tests because of its wide range of operating capabilities and large dry central cavity which extents through the center of the core. The goal of the fuels testing program is to demonstrate that the design and fabrication processes are of sufficient quality that the fuel will not fail at its design limit--up to a specified burnup, power density, and operating temperature. Transient testing is required to determine the fuel pin failure thresholds and to demonstrate that adequate fuel failure margins exist during the postulated design basis accidents.

  3. Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program

    SciTech Connect

    Garbett, K; Mendler, O J; Gardner, G C; Garnsey, R; Young, M Y

    1987-03-01

    In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faults and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.

  4. Transient Plume Model Testing Using LADEE Spacecraft Attitude Control System Operations

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael

    2011-01-01

    We have learned it is conceivable that the Neutral Mass Spectrometer on board the Lunarr Atmosphere Dust Environment Explorer (LADEE) could measure gases from surface-reflected Attitude Control System (ACS) thruster plume. At minimum altitude, the measurement would be maximized, and gravitational influence minimized ("short" time-of-flight (TOF) situation) Could use to verify aspects of thruster plume modeling Model the transient disturbance to NMS measurements due to ACS gases reflected from lunar surface Observe evolution of various model characteristics as measured by NMS Species magnitudes, TOF measurements, angular distribution, species separation effects

  5. Cultural Resource Investigations for the Resumption of Transient Testing of Nuclear Fuels and Material at the Idaho National Laboratory

    SciTech Connect

    Brenda R. Pace; Julie B. Williams

    2013-11-01

    The U. S. Department of Energy (DOE) has a need to test nuclear fuels under conditions that subject them to short bursts of intense, high-power radiation called ‘transient testing’ in order to gain important information necessary for licensing new nuclear fuels for use in U.S. nuclear power plants, for developing information to help improve current nuclear power plant performance and sustainability, for improving the affordability of new generation reactors, for developing recyclable nuclear fuels, and for developing fuels that inhibit any repurposing into nuclear weapons. To meet this mission need, DOE is considering alternatives for re-use and modification of existing nuclear reactor facilities to support a renewed transient testing program. One alternative under consideration involves restarting the Transient Reactor Test (TREAT) reactor located at the Materials and Fuels Complex (MFC) on the Idaho National Laboratory (INL) site in southeastern Idaho. This report summarizes cultural resource investigations conducted by the INL Cultural Resource Management Office in 2013 to support environmental review of activities associated with restarting the TREAT reactor at the INL. These investigations were completed in order to identify and assess the significance of cultural resources within areas of potential effect associated with the proposed action and determine if the TREAT alternative would affect significant cultural resources or historic properties that are eligible for nomination to the National Register of Historic Places. No archaeological resources were identified in the direct area of potential effects for the project, but four of the buildings proposed for modifications are evaluated as historic properties, potentially eligible for nomination to the National Register of Historic Places. This includes the TREAT reactor (building #), control building (building #), guardhouse (building #), and warehouse (building #). The proposed re-use of these historic

  6. Implementation and Testing of the First Prompt for Electromagnetic Counterparts to Gravitational Wave Transients

    NASA Technical Reports Server (NTRS)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Ajith, P.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Blackburn, L.; Camp, J. B.; Cannizzo, J.; Gehrels, N.

    2011-01-01

    A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec 17 2009 to Jan 8 2010 and Sep 2 to Oct 20 2010), a low-latency analysis pipeline was used to identify GW-event candidates and to reconstruct-maps of possible sky locations. A catalog of nearby galaxies and Milky Way globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline s ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with 50% or better probability with a few pointings of wide-field telescopes.

  7. Implementation and Testing of the First Prompt Search for Gravitational Wave Transients with Electromagnetic Counterparts

    NASA Technical Reports Server (NTRS)

    Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Ajith, P.; Allen, B.; Allen, G. S.; Ceron, E. Amador; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Blackburn, L.

    2012-01-01

    Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. A first program initiating EM follow-ups to possible transient GW events has been developed and exercised by the LIGO and Virgo community in association with several partners. In this paper, we describe and evaluate the methods used to promptly identify and localize GW event candidates and to request images of targeted sky locations. Methods. During two observing periods (Dec. 17, 2009 to Jan. 8, 2010 and Sep. 2 to Oct. 20, 2010), a low-latency analysis pipeline was used to identify GW event candidates and to reconstruct maps of possible sky locations. A catalog of nearby galaxies and MilkyWay globular clusters was used to select the most promising sky positions to be imaged, and this directional information was delivered to EM observatories with time lags of about thirty minutes. A Monte Carlo simulation has been used to evaluate the low-latency GW pipeline's ability to reconstruct source positions correctly. Results. For signals near the detection threshold, our low-latency algorithms often localized simulated GW burst signals to tens of square degrees, while neutron star/neutron star inspirals and neutron star/black hole inspirals were localized to a few hundred square degrees. Localization precision improves for moderately stronger signals. The correct sky location of signals well above threshold and originating from nearby galaxies may be observed with 50% or better probability with a few pointings of wide-field telescopes.

  8. Barometric pressure transient testing: Analysis methods and solution uniqueness: Final report

    SciTech Connect

    Hanson, J.M.

    1987-10-01

    Analysis of barometric pressure transients has been shown to be a useful tool in identifying the permeability structure in porous and permeable subsurface formations. The basic approach used in this technique requires monitoring surface barometric pressure fluctuations and the subsurface response to the surface pressure variation at one or more sensor locations over a period of time. These data are then used in conjunction with a given model of the subsurface to extract best estimates of one or more of the model parameters. A number of non-ideal conditions may affect solution uniqueness. These include the existence of noise on the data, sparse subsurface instrumentation, using an incorrect hole-formation model to interpret the data, and the frequency content of the recorded barometric pressure data. All of the work directed toward describing solution uniqueness and parameter uncertainty is presented. Other topics include refinement of several existing formation models, addressing the possibility of extracting an impulse response function from the measured data so that some kind of ''type-curve'' analysis can be applied, and the usefulness of carrying out the analysis in the frequency-domain. 5 refs., 21 figs., 10 tabs.

  9. Dynamic acousto-elastic test using continuous probe wave and transient vibration to investigate material nonlinearity.

    PubMed

    Eiras, J N; Vu, Q A; Lott, M; Payá, J; Garnier, V; Payan, C

    2016-07-01

    This study demonstrates the feasibility of the dynamic acousto-elastic effect of a continuous high frequency wave for investigating the material nonlinearity upon transient vibration. The approach is demonstrated on a concrete sample measuring 15×15×60cm(3). Two ultrasonic transducers (emitter and receiver) are placed at its middle span. A continuous high frequency wave of 500kHz propagates through the material and is modulated with a hammer blow. The position of the hammer blow on the sample is configured to promote the first bending mode of vibration. The use of a continuous wave allows discrete time extraction of the nonlinear behavior by a short-time Fourier transform approach, through the simultaneous comparison of a reference non-modulated signal and an impact-modulated signal. The hammer blow results in phase shifts and variations of signal amplitude between reference and perturbed signals, which are driven by the resonant frequency of the sample. Finally, a comprehensive analysis of the relaxation mechanisms (modulus and attenuation recovery) is conducted to untangle the coupled fast and slow hysteretic effects. PMID:27018754

  10. Role of Transient Mobility on Submonolayer Island Growth: Extensions and Testing

    NASA Astrophysics Data System (ADS)

    Morales Cifuentes, Josue; Einstein, Theodore; Pimpinelli, Alberto

    In studies of epitaxial growth a major goal is assessing the smallest stable cluster (i + 1 monomers, with i the critical nucleus size), by analyzing the capture zone distribution (CZD) or the scaling of incident flux F to the density of stable islands N (N ~Fα , with α the growth exponent). As noted in the previous talk, the GWD has well described the data in several experiments, including submonolayer para-hexaphenyl (6P) on amorphous mica (i ~ 3). Different scaling (Fα) for 6P at (small) large F is attributed to (DLA) ALA dynamics, i.e. i = (5) 7 +/- 2. Our recent theoretical work considered monomers propagating ballistically before thermalizing or attaching to islands, leading to scaling, non-monotonic crossover, and activation energies that account for the data and reconciling the values of i. We present applications to other experimental systems: 6P on SiO2 and pentacene (5A) on amorphous mica. We describe useful simplifying approximations, and preliminary kinetic Monte Carlo simulations including transient effects on growth. Work at UMD supported by NSF CHE 13-05892.

  11. Results of the latest transient well pressure tests at Cerro Prieto

    SciTech Connect

    Abril G, A.; Vargas G, C.

    1981-01-01

    The equipment used in the interference and two-rate flow tests carried out at the Cerro Prieto geothermal field during 1980 are described. The results of two interference tests are presented, one between wells M-110 and M-104, and the other between wells M-7 and Q-757. The data was interpreted using type curve matching analysis. Results of two-rate flow tests carried out in wells M-102 and M-7 are also discussed. A technique for making two-rate flow tests is proposed. This approach, which attempts to avoid the uncertainty of present flow-rate measurements, makes use of devices for direct measurements of separated water and steam. Conclusions based on the above interpretations and recommendations for future tests are presented.

  12. The Mirrortron experiment: A proof of principle test for a method of generating high transient potentials

    SciTech Connect

    Douglass, S.R.

    1993-09-01

    The Mirrortron is a concept in which heavy ions are accelerated by a large local transient space potential that is produced in a hot electron plasma. The purpose of this experiment is to begin a proof of principle experiment to investigate the feasibility of producing this space potential and its associated electric field. If a large magnetic field is suddenly generated in a hot electron plasma with a loss-cone distribution, then potentials on the order of the electron temperature are expected. This potential lasts a few tens of nanoseconds. The investigation begins with a theoretical analysis of this phenomenon giving the space potential as a function of the applied magnetic field. The theory is further extended to cases of relativistic electron distributions. This is then followed by design work on a mirror confinement system for hot electrons. In this experiment a 50--100 keV electron temperature plasma is created with electron cyclotron resonance heating using two frequencies of relatively low microwave power. The microwaves are coupled to resonant frequencies of the vacuum chamber. The volume averaged plasma density is measured to be in the 10{sup 9} cm{sup {minus}3} range. A strap coil and a flat Blumlein transmission line pulse generator were developed to produce a 150 gauss field within 70 ns. The strap coil was placed at the midplane of the mirror field, where the field is 700 gauss. Based on theoretical estimates and computer simulations a 20 kV potential is expected. Measurement of this potential is derived from the modulation of the current of a monoenergetic electron beam after it passes through the high potential region. The variation in the beam energy allows bunching to occur in transit to the detector.

  13. Geological Hypothesis Testing and Investigations of Coupling with Transient Electromagnetics (TEM)

    NASA Astrophysics Data System (ADS)

    Adams, A. C.; Moeller, M. M.; Snyder, E.; Workman, E. J.; Urquhart, S.; Bedrosian, P.; Pellerin, L.

    2014-12-01

    Transient electromagnetic (TEM) data were acquired in Borrego Canyon within the Santo Domingo Basin of the Rio Grande Rift, central New Mexico, during the 2014 Summer of Applied Geophysical Experience (SAGE) field program. TEM surveys were carried out in several regions both to investigate geologic structure and to illustrate the effects of coupling to anthropogenic structures. To determine an optimal survey configuration, 50, 100 and 200 m square transmitter loops were deployed; estimates of depth-of-investigation and logistical considerations determined that 50 m loops were sufficient for production-style measurements. A resistive (100s of ohm-m) layer was identified at a depth of 25-75 m at several locations, and interpreted as dismembered parts of one or more concealed volcanic flows, an interpretation consistent with Tertiary volcanic flows that cap the Santa Anna Mesa immediately to the south. TEM soundings were also made across an inferred fault to investigate whether fault offset is accompanied by lateral changes in electrical resistivity. Soundings within several hundred meters of the inferred fault strand were identical, indicating no resistivity contrast across the fault, and possibly an absence of recent activity. An old windmill and water tank, long-abandoned, offered an excellent laboratory to study the effect of coupling to metallic anthropogenic structures. The character of the measured data strongly suggests the water tank is in electrical contact with the earth (galvanic coupling), and an induced response was persistent to more than 1 second after current turn-off. Coupling effects could be identified at least 150 meters from the tank. Understanding the mechanism behind such coupling and the ability to identify coupled data are critical skills, as one-dimensional modeling of data is affected by such coupling producing artificial conductive layers at depth.

  14. The collection and analysis of transient test data using the mobile instrumentation data acquisition system (MIDAS)

    SciTech Connect

    Uncapher, W.L.; Arviso, M.

    1995-12-31

    Packages designed to transport radioactive materials are required to survive exposure to environments defined in Code of Federal Regulations. Cask designers can investigate package designs through structural and thermal testing of full-scale packages, components, or representative models. The acquisition of reliable response data from instrumentation measurement devices is an essential part of this testing activity. Sandia National Laboratories, under the sponsorship of the US Department of Energy (DOE), has developed the Mobile Instrumentation Data Acquisition System (MIDAS) dedicated to the collection and processing of structural and thermal data from regulatory tests.

  15. Numerical study of the SSME nozzle flow fields during transient operations: A comparison of the animated results with test

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Dumas, Catherine

    1993-01-01

    A computational fluid dynamics (CFD) model has been applied to study the transient flow phenomena of the nozzle and exhaust plume of the Space Shuttle Main Engine (SSME), fired at sea level. The CFD model is a time accurate, pressure based, reactive flow solver. A six-species hydrogen/oxygen equilibrium chemistry is used to describe the chemical-thermodynamics. An adaptive upwinding scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the temporal solution. Both engine start-up and shut-down processes were simulated. The elapse time is approximately five seconds for both cases. The computed results were animated and compared with the test. The images for the animation were created with PLOT3D and FAST and then animated with ABEKAS. The hysteresis effects, and the issues of free-shock separation, restricted-shock separation and the end-effects were addressed.

  16. Testing IH Instrumentation: Analysis of 1996-1998 Tank Ventilation Data in Terms of Characterizing a Transient Release

    SciTech Connect

    Droppo, James G.

    2004-07-01

    An analysis is conducted of the 1996-1998 Hanford tank ventilation studies of average ventilation rates to help define characteristics of shorter term releases. This effort is being conducted as part of the design of tests of Industrial Hygiene’s (IH) instrumentation ability to detect transient airborne plumes from tanks using current deployment strategies for tank operations. This analysis has improved our understanding of the variability of hourly average tank ventilation processes. However, the analysis was unable to discern the relative importance of emissions due to continuous releases and short-duration bursts of material. The key findings are as follows: 1. The ventilation of relatively well-sealed, passively ventilated tanks appears to be driven by a combination of pressure, buoyancy, and wind influences. The results of a best-fit analysis conducted with a single data set provide information on the hourly emission variability that IH instrumentation will need to detect. 2. Tank ventilation rates and tank emission rates are not the same. The studies found that the measured infiltration rates for a single tank are often a complex function of air exchanges between tanks and air exchanges with outdoor air. This situation greatly limits the usefulness of the ventilation data in defining vapor emission rates. 3. There is no evidence in the data to discern if the routine tank vapor releases occur over a short time (i.e., a puff) or over an extended time (i.e., continuous releases). Based on this analysis of the tank ventilation studies, it is also noted that 1) the hourly averaged emission peaks from the relatively well-sealed passively-vented tanks (such as U-103) are not a simple function of one meteorological parameter – but the peaks often are the result of the coincidence of temporal maximums in pressure, temperature, and wind influences and 2) a mechanistic combination modeling approach and/or field studies may be necessary to understand the short

  17. Numerical and field tests of hydraulic transients at Piva power plant

    NASA Astrophysics Data System (ADS)

    Giljen, Z.

    2014-03-01

    In 2009, a sophisticated field investigation was undertaken and later, in 2011, numerical tests were completed, on all three turbine units at the Piva hydroelectric power plant. These tests were made in order to assist in making decisions about the necessary scope of the reconstruction and modernisation of the Piva hydroelectric power plant, a plant originally constructed in the mid-1970s. More specifically, the investigation included several hydraulic conditions including both the start-up and stopping of each unit, load rejection under governor control from different initial powers, as well as emergency shut-down. Numerical results were obtained using the method of characteristics in a representation that included the full flow system and the characteristics of each associated Francis turbine. The impact of load rejection and emergency shut-down on the penstock pressure and turbine speed changes are reported and numerical and experimental results are compared, showing close agreement.

  18. Use of derivate for detecting linear impermeable barriers by transient pressure test

    SciTech Connect

    Ascencio, F.; Molinar R.

    1988-01-01

    The goal of this paper is to show a numerical method for evaluate distance at an impermeable barrier, using buildup and drawdown pressure test analysis. This technical needs of derivatives evaluation in transition zone defined between two classics semilog straight lines with slopes “m” and “2m” that are present in these systems. Complementary to this study the authors propose type curves for application in alternatives analysis. An illustrative example is showed using the proposed method.

  19. Transient thermal analysis and mechanical strength testing of pulsed laser welded ribbons to feedthru joints

    NASA Astrophysics Data System (ADS)

    Lin, Yaomin; Jiang, Guangqiang

    2012-03-01

    In this work, a laser welding process for attaching conducting ribbons to a miniaturized feedthru is introduced. A pulsed 1064nm Nd:YAG laser was used as an example in this study. A numerical simulation by means of finite element method (FEM) for the prediction of temperatures in the feedthru assembly is presented. The approach used was intended to solve the energy balance equation with appropriate initial and boundary conditions. A laser weld joint strength test was conducted using a Mechanical Strength Tester. The influence of processing parameters, such as laser power and pulse duration, on the temperature distribution and the weld joint strength are investigated and discussed.

  20. Single-Event Transient Testing of Low Dropout PNP Series Linear Voltage Regulators

    NASA Technical Reports Server (NTRS)

    Adell, Philippe; Allen, Gregory

    2013-01-01

    As demand for high-speed, on-board, digital-processing integrated circuits on spacecraft increases (field-programmable gate arrays and digital signal processors in particular), the need for the next generation point-of-load (POL) regulator becomes a prominent design issue. Shrinking process nodes have resulted in core rails dropping to values close to 1.0 V, drastically reducing margin to standard switching converters or regulators that power digital ICs. The goal of this task is to perform SET characterization of several commercial POL converters, and provide a discussion of the impact of these results to state-of-the-art digital processing IC through laser and heavy ion testing

  1. Transient elastodynamic model for beam defect interaction: application to non-destructive testing

    PubMed

    Raillon; Lecoeur-Taibi

    2000-03-01

    Modeling tools have been developed at the French Atomic Energy Commission (CEA) for the simulation of ultrasonic non-destructive testing inspections. In this paper the model for the prediction of echoes arising from defects within a piece (Mephisto) is presented and some examples are given and compared with experimental results. The model for computing wave defect interaction is based on Kirchhoff's approximation, and uses the principle of reciprocity and a mode-by-mode (between the transducer and the defect) calculation of the echoes. It accounts for possible mode conversions. These approximations and other approximations for the radiated field incident on the defect allow us to obtain a formulation of the echo received at the transducer, which is able to be computed rapidly.

  2. Transient forces generated by projectiles on variable quality mouthguards monitored by instrumented impact testing

    PubMed Central

    Warnet, L; Greasley, A

    2001-01-01

    Objectives—(a) To determine the force-time trace that occurs when a spring mounted simulated upper jaw is impacted; (b) to examine if mouthguards of variable quality have significant influence on such force-time traces; (c) to attempt to relate physical events to the profile of the force-time traces recorded. Methods—A simulated jaw, consisting of ceramic teeth inserted into a hard rubber arch reinforced with a composite jawbone, was fitted with various mouthguards as part of a previous round robin study. A clinical assessment distinguished good, bad, and poor mouthguards, and these were each fitted to the jaw, which was then submitted to instrumental impact tests under conditions expected to produce tooth fractures. The force-time trace was recorded for such impact events. Results—The spring mounting method caused two distinct peaks in the force-time trace. The initial one was related to inertia effects and showed an increase in magnitude with impactor velocity as expected. The second peak showed features that were related to the differences in the mouthguards selected. Conclusions—The use of a force washer within a conical ended impactor enabled force-time traces to be recorded during the impact of a spring mounted simulated jaw fitted with mouthguards of variable quality. The spring mounting system causes an initial inertial peak followed by a second peak once the spring mount has fully compressed. Good fitting guards, which keep most teeth intact, result in high stiffness targets that in turn generate high reaction forces in the impactor. If the spring mounting is omitted, the two peaks are combined to give even higher reaction forces. The force-time trace offers some potential for assessing both overall mouthguard performance and individual events during the impact sequence. Mouthguards with good retention to the jaw remained attached during the impact event and helped to preserve the structural integrity of the target. This in turn developed high

  3. Acoustic Data Processing and Transient Signal Analysis for the Hybrid Wing Body 14- by 22-Foot Subsonic Wind Tunnel Test

    NASA Technical Reports Server (NTRS)

    Bahr, Christopher J.; Brooks, Thomas F.; Humphreys, William M.; Spalt, Taylor B.; Stead, Daniel J.

    2014-01-01

    An advanced vehicle concept, the HWB N2A-EXTE aircraft design, was tested in NASA Langley's 14- by 22-Foot Subsonic Wind Tunnel to study its acoustic characteristics for var- ious propulsion system installation and airframe con gurations. A signi cant upgrade to existing data processing systems was implemented, with a focus on portability and a re- duction in turnaround time. These requirements were met by updating codes originally written for a cluster environment and transferring them to a local workstation while en- abling GPU computing. Post-test, additional processing of the time series was required to remove transient hydrodynamic gusts from some of the microphone time series. A novel automated procedure was developed to analyze and reject contaminated blocks of data, under the assumption that the desired acoustic signal of interest was a band-limited sta- tionary random process, and of lower variance than the hydrodynamic contamination. The procedure is shown to successfully identify and remove contaminated blocks of data and retain the desired acoustic signal. Additional corrections to the data, mainly background subtraction, shear layer refraction calculations, atmospheric attenuation and microphone directivity corrections, were all necessary for initial analysis and noise assessments. These were implemented for the post-processing of spectral data, and are shown to behave as expected.

  4. Neutronics, steady-state, and transient analyses for the Poland MARIA reactor for irradiation testing of LEU lead test fuel assemblies from CERCA : ANL independent verification results.

    SciTech Connect

    Garner, P. L.; Hanan, N. A.

    2011-06-07

    The MARIA reactor at the Institute of Atomic Energy (IAE) in Swierk (30 km SE of Warsaw) in the Republic of Poland is considering conversion from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel assemblies (FA). The FA design in MARIA is rather unique; a suitable LEU FA has never been designed or tested. IAE has contracted with CERCA (the fuel supply portion of AREVA in France) to supply 2 lead test assemblies (LTA). The LTAs will be irradiated in MARIA to burnup level of at least 40% for both LTAs and to 60% for one LTA. IAE may decide to purchase additional LEU FAs for a full core conversion after the test irradiation. The Reactor Safety Committee within IAE and the National Atomic Energy Agency in Poland (PAA) must approve the LTA irradiation process. The approval will be based, in part, on IAE submitting revisions to portions of the Safety Analysis Report (SAR) which are affected by the insertion of the LTAs. (A similar process will be required for the full core conversion to LEU fuel.) The analysis required was established during working meetings between Argonne National Laboratory (ANL) and IAE staff during August 2006, subsequent email correspondence, and subsequent staff visits. The analysis needs to consider the current high-enriched uranium (HEU) core and 4 core configurations containing 1 and 2 LEU LTAs in various core positions. Calculations have been performed at ANL in support of the LTA irradiation. These calculations are summarized in this report and include criticality, burn-up, neutronics parameters, steady-state thermal hydraulics, and postulated transients. These calculations have been performed at the request of the IAE staff, who are performing similar calculations to be used in their SAR amendment submittal to the PAA. The ANL analysis has been performed independently from that being performed by IAE and should only be used as one step in the verification process.

  5. Particle Tracking-Based Strategies For Simulating Transport in a Transient Groundwater Flow Field at Yucca Flat, Nevada Test Site, USA

    NASA Astrophysics Data System (ADS)

    Keating, E. H.; Srinivasan, G.; Kang, Q.; Li, C.; Dash, Z.; Kwicklis, E. M.

    2009-12-01

    Developing probabilistic-based calculations of contaminant concentrations over the next 1000 years at Yucca Flat, Nevada Test site, require tremendous computational effort in this highly complex hydrogeologic surface environment. The sources of contamination, underground nuclear tests conducted between 1951 and 1992, not only released radionuclides to the subsurface but also created abrupt, significant changes in rock properties and caused large transients in the measured hydraulic gradients. To efficiently model contaminant migration from these sources we use a particle-based approach within a transient flow field. Here, we present results using two methods; first, an explicit representation of time-varying sources using large numbers of particles introduced at source-specific rates over time, each representing a unique mass of solute. This method provides good results, but is computationally expensive since sensitivity to uncertainty in source term and transport parameters can only be explored with discrete process-model runs. The second method employs a convolution method (PLUMECALC) which can efficiently consider a large number of variations in the source terms and in certain transport parameters with a single process-model run. Implementation of this second approach required extension of the existing methodology to conditions of transient flow. We find very good comparison between the two methods on small test problems and excellent computational advantages when applying the convolution method in the NTS application

  6. Initial Neutronics Analyses for HEU to LEU Fuel Conversion of the Transient Reactor Test Facility (TREAT) at the Idaho National Laboratory

    SciTech Connect

    Kontogeorgakos, D.; Derstine, K.; Wright, A.; Bauer, T.; Stevens, J.

    2013-06-01

    The purpose of the TREAT reactor is to generate large transient neutron pulses in test samples without over-heating the core to simulate fuel assembly accident conditions. The power transients in the present HEU core are inherently self-limiting such that the core prevents itself from overheating even in the event of a reactivity insertion accident. The objective of this study was to support the assessment of the feasibility of the TREAT core conversion based on the present reactor performance metrics and the technical specifications of the HEU core. The LEU fuel assembly studied had the same overall design, materials (UO2 particles finely dispersed in graphite) and impurities content as the HEU fuel assembly. The Monte Carlo N–Particle code (MCNP) and the point kinetics code TREKIN were used in the analyses.

  7. Testing the necessity of transient spikes in the drivers for creating a storm-time ring current

    NASA Astrophysics Data System (ADS)

    Liemohn, M. W.; Ilie, R.; Ridley, A. J.; Kozyra, J. U.; Thomsen, M. F.; Borovsky, J. E.

    2007-12-01

    The role of transient spikes in upstream solar wind parameters and near-Earth plasma sheet parameters is investigated through a series of numerical simulations. During magnetic storms, the near-Earth plasma sheet density (as observed at geosynchronous altitude) is often enhanced relative to its normal, quiescent level. In addition to a baseline increase of the density of up to a few per cubic centimeter lasting several hours, there are usually short-lived (a few to tens of minutes) increases on top of this (up to double the baseline). In addition, the solar wind parameters also often have numerous short-lived spikes and fluctuations within it. The question then arises of the relative contribution of these transient spikes in the drivers to the storm-time ring current intensity. To address this issue, a series of simulations are conducted using the Hot Electron and Ion Drift Integrator (HEIDI) model (formerly the Michigan version of RAM). Various running averages of the upstream solar wind conditions and geosynchronous orbit nightside boundary conditions are used to drive HEIDI. It is found that the spikes are simply adding a linear contribution to the ring current intensity over the baseline (averaged) input levels, and that any nonlinear influences occur beyond the HEIDI simulation domain (i.e., at high latitudes or in the tail). That is, the spikes do not last long enough to develop nonlinear influences on the ring current's total energy content. The HEIDI results are compared against global magnetospheric modeling results using averaged input parameters into the Space Weather Modeling Framework (SWMF), which show a nonlinear response to transient spikes.

  8. Effect of transient liquid phase (TLP) bonding on the ductility of a Ni-base single crystal superalloy in a stress rupture test

    SciTech Connect

    Liu, J.D. Jin, T.; Zhao, N.R.; Wang, Z.H.; Sun, X.F.; Guan, H.R.; Hu, Z.Q.

    2008-01-15

    A Ni-base single crystal superalloy was transient liquid phase (TLP) bonded using a Ni-Cr-B amorphous foil at 1230 deg. C for 8 h. Stress rupture tests of the TLP joint and a matrix sample were carried out at 982 deg. C/248 MPa and 1010 deg. C/248 MPa. The microstructures and fracture surfaces were studied using scanning electron microscopy (SEM). Transmission electron microscopy (TEM) investigations were performed after creep rupture testing to examine the deformation substructures. The results show that the stress rupture ductility of TLP joints is significantly decreased compared to the matrix sample. This reduction of the ductility of TLP joints can be attributed to solid solution strengthening by boron atoms, subgrain boundaries formed in the bonding zone and the concentration of creep cavities formed during the last stage of the stress rupture test.

  9. Outbreak of Transient Conversions of the QuantiFERON-TB Gold In-Tube Test in Laboratory Health Care Worker Screenings

    PubMed Central

    Peracchi, Marta; Zorzi, Diego; Fiorio, Silvia; Fallico, Loredana; Palù, Giorgio

    2012-01-01

    Gamma interferon release assays were recently introduced in health care worker (HCWs) screenings for tuberculosis surveillance. In longitudinal surveys, conversions and reversions are seen, and yet whether these changes are unspecific or are an expression of new infections and microbial clearance remains unclear. In order to further elucidate these changes, we analyzed an outbreak of 15 transient conversions in 53 HCWs who operate in the same laboratory and handle specimens potentially containing Mycobacterium tuberculosis who underwent screening by the QuantiFERON-TB Gold In-Tube (QFT-GIT) test between 11 May and 30 June 2010: 15/46 (33%) negative HCWs showed a conversion and then reverted after 7 to 107 days. To validate these results, an evaluation of methodological procedures and test reliability, as well as an analysis of results obtained during the same period and processed by the same laboratory, was carried out. For the latter purpose, QFT-GIT results determined for 78 ward HCWs who underwent screening during the same period and were employed in departments with at least 3 infectious tuberculosis patients per year or had cared for an infectious patient without airborne precautions were analyzed with the following results: 6/63 (9%) HCWs with negative results in 3 different departments showed transient conversion (P = 0.002; odds ratio, 4.60; 95% confidence interval, 1.62 to 13.04). A retrospective survey of in-house biosafety practices led to determination of a single exposure factor within the laboratory. These data emphasize the validity of the hypothesis that a transient conversion demonstrates the presence of a real tubercular infection and could be an important indicator for occupational biosafety concerns. They also confirm that subjects with recent conversion should be retested before chest radiography and chemotherapy is offered. PMID:22518010

  10. LUNAR OUTGASSING, TRANSIENT PHENOMENA, AND THE RETURN TO THE MOON. II. PREDICTIONS AND TESTS FOR OUTGASSING/REGOLITH INTERACTIONS

    SciTech Connect

    Crotts, Arlin P. S.; Hummels, Cameron

    2009-12-20

    We follow Paper I with predictions of how gas leaking through the lunar surface could influence the regolith, as might be observed via optical transient lunar phenomena (TLPs) and related effects. We touch on several processes, but concentrate on low and high flow rate extremes, which are perhaps the most likely. We model explosive outgassing for the smallest gas overpressure at the regolith base that releases the regolith plug above it. This disturbance's timescale and affected area are consistent with observed TLPs; we also discuss other effects. For slow flow, escape through the regolith is prolonged by low diffusivity. Water, found recently in deep magma samples, is unique among candidate volatiles, capable of freezing between the regolith base and surface, especially near the lunar poles. For major outgassing sites, we consider the possible accumulation of water ice. Over geological time, ice accumulation can evolve downward through the regolith. Depending on gases additional to water, regolith diffusivity might be suppressed chemically, blocking seepage and forcing the ice zone to expand to larger areas, up to km{sup 2} scales, again, particularly at high latitudes. We propose an empirical path forward, wherein current and forthcoming technologies provide controlled, sensitive probes of outgassing. The optical transient/outgassing connection, addressed via Earth-based remote sensing, suggests imaging and/or spectroscopy, but aspects of lunar outgassing might be more covert, as indicated above. TLPs betray some outgassing, but does outgassing necessarily produce TLPs? We also suggest more intrusive techniques from radar to in situ probes. Understanding lunar volatiles seems promising in terms of resource exploitation for human exploration of the Moon and beyond, and offers interesting scientific goals in its own right. Many of these approaches should be practiced in a pristine lunar atmosphere, before significant confusing signals likely to be produced upon

  11. The LOFAR Transients Pipeline

    NASA Astrophysics Data System (ADS)

    Swinbank, John D.; Staley, Tim D.; Molenaar, Gijs J.; Rol, Evert; Rowlinson, Antonia; Scheers, Bart; Spreeuw, Hanno; Bell, Martin E.; Broderick, Jess W.; Carbone, Dario; Garsden, Hugh; van der Horst, Alexander J.; Law, Casey J.; Wise, Michael; Breton, Rene P.; Cendes, Yvette; Corbel, Stéphane; Eislöffel, Jochen; Falcke, Heino; Fender, Rob; Grießmeier, Jean-Mathias; Hessels, Jason W. T.; Stappers, Benjamin W.; Stewart, Adam J.; Wijers, Ralph A. M. J.; Wijnands, Rudy; Zarka, Philippe

    2015-06-01

    Current and future astronomical survey facilities provide a remarkably rich opportunity for transient astronomy, combining unprecedented fields of view with high sensitivity and the ability to access previously unexplored wavelength regimes. This is particularly true of LOFAR, a recently-commissioned, low-frequency radio interferometer, based in the Netherlands and with stations across Europe. The identification of and response to transients is one of LOFAR's key science goals. However, the large data volumes which LOFAR produces, combined with the scientific requirement for rapid response, make automation essential. To support this, we have developed the LOFAR Transients Pipeline, or TraP. The TraP ingests multi-frequency image data from LOFAR or other instruments and searches it for transients and variables, providing automatic alerts of significant detections and populating a lightcurve database for further analysis by astronomers. Here, we discuss the scientific goals of the TraP and how it has been designed to meet them. We describe its implementation, including both the algorithms adopted to maximize performance as well as the development methodology used to ensure it is robust and reliable, particularly in the presence of artefacts typical of radio astronomy imaging. Finally, we report on a series of tests of the pipeline carried out using simulated LOFAR observations with a known population of transients.

  12. Characterizing SI Engine Transient Fuel Consumption in ALPHA

    EPA Science Inventory

    Examine typical transient engine operation encountered over the EPA's vehicle and engine testing drive cycles to characterize that transient fuel usage, and then describe the changes made to ALPHA to better model transient engine operation.

  13. Statistical searches for microlensing events in large, non-uniformly sampled time-domain surveys: A test using palomar transient factory data

    SciTech Connect

    Price-Whelan, Adrian M.; Agüeros, Marcel A.; Fournier, Amanda P.; Street, Rachel; Ofek, Eran O.; Covey, Kevin R.; Levitan, David; Sesar, Branimir; Laher, Russ R.; Surace, Jason

    2014-01-20

    Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its ∼20,000 deg{sup 2} footprint. While the median 7.26 deg{sup 2} PTF field has been imaged ∼40 times in the R band, ∼2300 deg{sup 2} have been observed >100 times. We use PTF data to study the trade off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a selection method using this statistic and apply it to data from fields with >10 R-band observations, 1.1 × 10{sup 9} light curves, uncovering three candidate microlensing events. We lack simultaneous, multi-color photometry to confirm these as microlensing events. However, their number is consistent with predictions for the event rate in the PTF footprint over the survey's three years of operations, as estimated from near-field microlensing models. This work can help constrain all-sky event rate predictions and tests microlensing signal recovery in large data sets, which will be useful to future time-domain surveys, such as that planned with the Large Synoptic Survey Telescope.

  14. Statistical Searches for Microlensing Events in Large, Non-uniformly Sampled Time-Domain Surveys: A Test Using Palomar Transient Factory Data

    NASA Astrophysics Data System (ADS)

    Price-Whelan, Adrian M.; Agüeros, Marcel A.; Fournier, Amanda P.; Street, Rachel; Ofek, Eran O.; Covey, Kevin R.; Levitan, David; Laher, Russ R.; Sesar, Branimir; Surace, Jason

    2014-01-01

    Many photometric time-domain surveys are driven by specific goals, such as searches for supernovae or transiting exoplanets, which set the cadence with which fields are re-imaged. In the case of the Palomar Transient Factory (PTF), several sub-surveys are conducted in parallel, leading to non-uniform sampling over its ~20,000 deg2 footprint. While the median 7.26 deg2 PTF field has been imaged ~40 times in the R band, ~2300 deg2 have been observed >100 times. We use PTF data to study the trade off between searching for microlensing events in a survey whose footprint is much larger than that of typical microlensing searches, but with far-from-optimal time sampling. To examine the probability that microlensing events can be recovered in these data, we test statistics used on uniformly sampled data to identify variables and transients. We find that the von Neumann ratio performs best for identifying simulated microlensing events in our data. We develop a selection method using this statistic and apply it to data from fields with >10 R-band observations, 1.1 × 109 light curves, uncovering three candidate microlensing events. We lack simultaneous, multi-color photometry to confirm these as microlensing events. However, their number is consistent with predictions for the event rate in the PTF footprint over the survey's three years of operations, as estimated from near-field microlensing models. This work can help constrain all-sky event rate predictions and tests microlensing signal recovery in large data sets, which will be useful to future time-domain surveys, such as that planned with the Large Synoptic Survey Telescope.

  15. Fluid Structure Interaction in a Cold Flow Test and Transient CFD Analysis of Out-of-Round Nozzles

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph; Brown, Andrew; McDaniels, David; Wang, Ten-See

    2010-01-01

    This viewgraph presentation describes two nozzle fluid flow interactions. They include: 1) Cold flow nozzle tests with fluid-structure interaction at nozzle separated flow; and 2) CFD analysis for nozzle flow and side loads of nozzle extensions with various out-of-round cases.

  16. RELAP5/MOD3 Analysis of Transient Steam-Generator Behavior During Turbine Trip Test of a Prototype Fast Breeder Reactor MONJU

    SciTech Connect

    Yoshihisa Shindo; Hiroshi Endo; Tomoko Ishizu; Kazuo Haga

    2006-07-01

    In order to develop a thermal-hydraulic model of the steam-generator (SG) to simulate transient phenomena in the sodium cooled fast breeder reactor (FBR) MONJU, Japan Nuclear Energy Safety Organization (JNES) verified the SG model using the RELAP5/MOD3 code against the results of the turbine trip test at a 40% power load of MONJU. The modeling by using RELAP5 was considered to explain the significant observed behaviors of the pressure and the temperature of the EV steam outlet, and the temperature of water supply distributing piping till 600 seconds after the turbine trip. The analysis results of these behaviors showed good agreement with the test results based on results of parameter study as the blow efficiency (release coef.) and heat transferred from the helical coil region to the down-comer (temperature heating down-comer tubes). It was found that the RELAP5/MOD3 code with a two-fluids model can predict well the physical situation: the gas-phase of steam generated by the decompression boiling moves upward in the down-comer tubes accompanied by the enthalpy increase of the water supply chambers; and that the pressure change of a 'shoulder' like shape is induced by the mass balance between the steam mass generated in the down-comer tubes and the steam mass blown from the SG. The applicability of RELAP5/MOD3 to SG modeling was confirmed by simulating the actual FBR system. (authors)

  17. Impact of typical steady-state conditions and transient conditions on flow ripple and its test accuracy for axial piston pump

    NASA Astrophysics Data System (ADS)

    Xu, Bing; Hu, Min; Zhang, Junhui

    2015-09-01

    The current research about the flow ripple of axial piston pump mainly focuses on the effect of the structure of parts on the flow ripple. Therein, the structure of parts are usually designed and optimized at rated working conditions. However, the pump usually has to work in large-scale and time-variant working conditions. Therefore, the flow ripple characteristics of pump and analysis for its test accuracy with respect to variant steady-state conditions and transient conditions in a wide range of operating parameters are focused in this paper. First, a simulation model has been constructed, which takes the kinematics of oil film within friction pairs into account for higher accuracy. Afterwards, a test bed which adopts Secondary Source Method is built to verify the model. The simulation and tests results show that the angular position of the piston, corresponding to the position where the peak flow ripple is produced, varies with the different pressure. The pulsating amplitude and pulsation rate of flow ripple increase with the rise of pressure and the variation rate of pressure. For the pump working at a constant speed, the flow pulsation rate decreases dramatically with the increasing speed when the speed is less than 27.78% of the maximum speed, subsequently presents a small decrease tendency with the speed further increasing. With the rise of the variation rate of speed, the pulsating amplitude and pulsation rate of flow ripple increase. As the swash plate angle augments, the pulsating amplitude of flow ripple increases, nevertheless the flow pulsation rate decreases. In contrast with the effect of the variation of pressure, the test accuracy of flow ripple is more sensitive to the variation of speed. It makes the test accuracy above 96.20% available for the pulsating amplitude of pressure deviating within a range of ±6% from the mean pressure. However, with a variation of speed deviating within a range of ±2% from the mean speed, the attainable test

  18. Transient characteristics of rocket turbopumps

    NASA Astrophysics Data System (ADS)

    Shimura, Takashi; Watanabe, Mitsuo

    Transient characteristics of high-speed, high-pressure cryogenic turbopumps for rocket engines were examined experimentally by starting and stopping several rocket turbopumps rapidly by gas turbine drive. Aspects of transient characteristics studied were instantaneous pump head coefficient and pump efficiency, cavitation growth in the inducer during rapid acceleration, effects of the starting mode related to the propulsion system mission, and transient behavior of a self-balancing type axial thrust balancing system. Based on the test results, the feasibility of definite starting modes for the LE-5 turbopump was confirmed and the self-balancing type axial thrust balancing system for the LE-7 LOX turbopump was completed.

  19. Reducing carbonyl emissions from a heavy-duty diesel engine at US transient cycle test by use of paraffinic/biodiesel blends

    NASA Astrophysics Data System (ADS)

    Yuan, Chung-Shin; Lin, Yuan-Chung; Tsai, Cheng-Hsien; Wu, Chia-Chieh; Lin, Yu-Sheng

    2009-12-01

    Formaldehyde and acetaldehyde are toxic carcinogens so their reductions in diesel-engine emissions are desirable. This study investigated emissions of carbonyl compounds (CBCs) from an HDDE (heavy-duty diesel engine) at US transient cycle test, using five test fuels: premium diesel fuel (D100), P100 (100% palm-biodiesel), P20 (20% palm-biodiesel + 80% premium diesel fuel), PF80P20 (80% paraffinic fuel + 20% palm-biodiesel), and PF95P05 (95% paraffinic fuel + 5% palm-biodiesel). Experimental results indicate that formaldehyde was the major carbonyl in the exhaust, accounting for 70.1-76.2% of total CBC concentrations for all test fuels. In comparison with D100 (172 mg BHP -1 h -1), the reductions of formaldehyde and acetaldehyde emission factor for P100, P20, PF80P20, and PF95P05 were (-16.8%, -61.8%), (-10.0%, -39.0%), (21.3%, 1.10%), and (31.1%, 19.5%), respectively. Using P100 and P20 instead of D100 in the HDDE increased CBC concentrations by 14.5% and 3.28%, respectively, but using PF80P20 and PF95P05 significantly reduced CBC concentrations by 30.3% and 23.7%, respectively. Using P100 and P20 instead of D100 (2867 ton yr -1) in the HDDE increased CBC emissions by 240 and 224 ton yr -1, respectively, but using PF80P20, and PF95P05 instead of D100 in the HDDE decreased CBC emissions by 711 and 899 ton yr -1, respectively. The above results indicate that the wide usage of paraffinic-palmbiodiesel blends as alternative fuels could protect the environment.

  20. Transient enthalpy probe development

    NASA Astrophysics Data System (ADS)

    Bennett, Brian K.

    A reliable diagnostic probe has been developed to measure the local enthalpy in high-pressure, arc heated test streams that simulate atmospheric reentry conditions. The probe employs the double sonic-throat technique and is designed for the sweep (transient) mode to survive the severe heating environment. Tests in the high-pressure arc heater facilities show that, under certain conditions, the enthalpy probe measurements are in good agreement with enthalpy profiles inferred from heat flux measurements using the theory of Fay and Riddell (1958).

  1. A Transient Numerical Simulation of Perched Ground-Water Flow at the Test Reactor Area, Idaho National Engineering and Environmental Laboratory, Idaho, 1952-94

    SciTech Connect

    B. R. Orr

    1999-11-01

    Studies of flow through the unsaturated zone and perched ground-water zones above the Snake River Plain aquifer are part of the overall assessment of ground-water flow and determination of the fate and transport of contaminants in the subsurface at the Idaho National Engineering and Environmental Laboratory (INEEL). These studies include definition of the hydrologic controls on the formation of perched ground-water zones and description of the transport and fate of wastewater constituents as they moved through the unsaturated zone. The definition of hydrologic controls requires stratigraphic correlation of basalt flows and sedimentary interbeds within the saturated zone, analysis of hydraulic properties of unsaturated-zone rocks, numerical modeling of the formation of perched ground-water zones, and batch and column experiments to determine rock-water geochemical processes. This report describes the development of a transient numerical simulation that was used to evaluate a conceptual model of flow through perched ground-water zones beneath wastewater infiltration ponds at the Test Reactor Area (TRA).

  2. Evaluating quantitative 3-D image analysis as a design tool for low enriched uranium fuel compacts for the transient reactor test facility: A preliminary study

    DOE PAGES

    Kane, J. J.; van Rooyen, I. J.; Craft, A. E.; Roney, T. J.; Morrell, S. R.

    2016-02-05

    In this study, 3-D image analysis when combined with a non-destructive examination technique such as X-ray computed tomography (CT) provides a highly quantitative tool for the investigation of a material’s structure. In this investigation 3-D image analysis and X-ray CT were combined to analyze the microstructure of a preliminary subsized fuel compact for the Transient Reactor Test Facility’s low enriched uranium conversion program to assess the feasibility of the combined techniques for use in the optimization of the fuel compact fabrication process. The quantitative image analysis focused on determining the size and spatial distribution of the surrogate fuel particles andmore » the size, shape, and orientation of voids within the compact. Additionally, the maximum effect of microstructural features on heat transfer through the carbonaceous matrix of the preliminary compact was estimated. The surrogate fuel particles occupied 0.8% of the compact by volume with a log-normal distribution of particle sizes with a mean diameter of 39 μm and a standard deviation of 16 μm. Roughly 39% of the particles had a diameter greater than the specified maximum particle size of 44 μm suggesting that the particles agglomerate during fabrication. The local volume fraction of particles also varies significantly within the compact although uniformities appear to be evenly dispersed throughout the analysed volume. The voids produced during fabrication were on average plate-like in nature with their major axis oriented perpendicular to the compaction direction of the compact. Finally, the microstructure, mainly the large preferentially oriented voids, may cause a small degree of anisotropy in the thermal diffusivity within the compact. α∥/α⊥, the ratio of thermal diffusivities parallel to and perpendicular to the compaction direction are expected to be no less than 0.95 with an upper bound of 1.« less

  3. Transient neonatal tyrosinaemia.

    PubMed

    Rice, D N; Houston, I B; Lyon, I C; Macarthur, B A; Mullins, P R; Veale, A M; Guthrie, R

    1989-01-01

    Children who had presented with transient neonatal tyrosinaemia (TNT) were compared with a group of unaffected controls at 7-9 years of age. A comprehensive psychometric assessment revealed significant differences between the groups in adaptive behaviour, psycholinguistic abilities, and speed of learning. In nearly all components of the tests used, higher levels of TNT were associated with lower levels of performance. This study demonstrates that TNT, a condition commonly regarded as benign in the short term, has long-term effects which may be detrimental to the child in school.

  4. Detecting aseismic transients using seismicity

    NASA Astrophysics Data System (ADS)

    Reverso, T.; Marsan, D.; Helmstetter, A.

    2013-12-01

    Aseismic deformation transients occur in different tectonic context. In subduction zones, aseismic slip events are of paramount importance for understanding earthquake hazard, and for estimating the potential for future mega-thrust events. Aseismic slip is however difficult to detect except for the largest cases using GPS data. Here, we propose a systematic detection of aseismic deformation transients based on seismicity data alone. We search for transient increases in background seismicity rate, that would indicate the presence of an aseismic event. To that purpose, we make use of an ETAS model in space and time, to distinguish earthquakes due to background processes from aftershocks. We optimize the model parameters, and test the sensitivity of the results with changes in parameters. Given the 'best' model, we measure the statistical significance of the departure of the local (in time and space) background rate with the 'normal' background rate. Significant departure then indicates the need to temporary increase the background rate in order to explain the observed earthquake occurrences. We thus can single out such episodes of aseismic transients, and characterize their duration and spatial extent. Applying this method to the Aleutian subduction zone reveals several instances of aseismic deformation transients, at various spatial and temporal scales. We further investigate how these transients are organized along the subduction interface, and in time.

  5. Transient tachypnea - newborn

    MedlinePlus

    TTN; Wet lungs - newborns; Retained fetal lung fluid; Transient RDS; Prolonged transition; Neonatal - transient tachypnea ... As the baby grows in the womb, the lungs make a special fluid. This fluid fills the ...

  6. Transient drainage summary report

    SciTech Connect

    1996-09-01

    This report summarizes the history of transient drainage issues on the Uranium Mill Tailings Remedial Action (UMTRA) Project. It defines and describes the UMTRA Project disposal cell transient drainage process and chronicles UMTRA Project treatment of the transient drainage phenomenon. Section 4.0 includes a conceptual cross section of each UMTRA Project disposal site and summarizes design and construction information, the ground water protection strategy, and the potential for transient drainage.

  7. Transient Ischemic Attack

    MedlinePlus

    Transient Ischemic Attack TIA , or transient ischemic attack, is a "mini stroke" that occurs when a blood clot blocks an artery for a short time. The only ... TIA is that with TIA the blockage is transient (temporary). TIA symptoms occur rapidly and last a ...

  8. Transient congenital hypothyroidism

    PubMed Central

    Bhavani, Nisha

    2011-01-01

    Transient thyroid function abnormalities in the new born which revert back to normal after varying periods of time are mostly identified in the neonatal screening tests for thyroid and are becoming more common because of the survival of many more premature infants. It can be due to factors primarily affecting the thyroid-like iodine deficiency or excess, maternal thyroid-stimulating hormone receptor (TSHR) antibodies, maternal use of antithyroid drugs, DUOX 2 (dual oxidase 2) mutations, and prematurity or those that affect the pituitary-like untreated maternal hyperthyroidism, prematurity, and drugs. Most of these require only observation, whereas some, such as those due to maternal TSHR antibodies may last for upto three-to-six months and may necessitate treatment. Isolated hyperthyrotropinemia (normal Tetraiodothyronine (T4) and high Thyroid Stimulating hormone (TSH)) may persist as subclinical hypothyroidism in childhood. Transient hypothyroxinemia (low T4 and normal TSH) is very common in premature babies. The recognition of these conditions will obviate the risks associated with unnecessary thyroxine supplementation in childhood and parental concerns of a life long illness in their offspring. PMID:21966647

  9. Perturbations for transient acceleration

    SciTech Connect

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried; Hipólito-Ricaldi, Wiliam S. E-mail: hipolito@ceunes.ufes.br

    2012-04-01

    According to the standard ΛCDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  10. Model refinement using transient response

    SciTech Connect

    Dohrmann, C.R.; Carne, T.G.

    1997-12-01

    A method is presented for estimating uncertain or unknown parameters in a mathematical model using measurements of transient response. The method is based on a least squares formulation in which the differences between the model and test-based responses are minimized. An application of the method is presented for a nonlinear structural dynamic system. The method is also applied to a model of the Department of Energy armored tractor trailer. For the subject problem, the transient response was generated by driving the vehicle over a bump of prescribed shape and size. Results from the analysis and inspection of the test data revealed that a linear model of the vehicle`s suspension is not adequate to accurately predict the response caused by the bump.

  11. Perception of acoustic transients

    NASA Astrophysics Data System (ADS)

    Howard, J. H., Jr.

    1984-01-01

    The research investigates the role of knowledge based or top-down processing in the perception of nonlinguistic, transient signals. The experiments address issues in transient pattern classification, target observation, attentional focusing, auditory induction, and computer based performance aids. The theoretical significance and naval relevance of the research is considered.

  12. Transient epileptic amnesia: a concise review.

    PubMed

    Asadi-Pooya, Ali A

    2014-02-01

    Transient epileptic amnesia (TEA) is a distinctive syndrome and comprises episodic transient amnesia with an epileptic basis, without impairment of other aspects of cognitive function. Additional interictal memory deficits are common in TEA. An epileptic origin, after other etiologies have been excluded, should be considered and carefully investigated in patients complaining of isolated memory disturbances, particularly with recurrent short-lasting amnesic attacks. In all suspected cases of epilepsy, a detailed clinical history is of paramount importance, but ancillary tests including EEG and MRI could be very helpful. Transient epileptic amnesia is typically a benign and treatable condition. Future studies should investigate the exact mechanism(s) of this unique syndrome.

  13. Temperature in a J47-25 Turbojet-engine Combustor and Turbine Sections During Steady-state and Transient Operation in a Sea-level Test Stand

    NASA Technical Reports Server (NTRS)

    Morse, C R; Johnston, J R

    1955-01-01

    In order to determine the conditions of engine operation causing the most severe thermal stresses in the hot parts of a turbojet engine, a J47-25 engine was instrumented with thermocouples and operated to obtain engine material temperatures under steady-state and transient conditions. Temperatures measured during rated take-off conditions of nozzle guide vanes downstream of a single combustor differed on the order of 400 degrees F depending on the relation of the blades position to the highest temperature zone of the burner. Under the same operation conditions, measured midspan temperatures in a nozzle guide vane in the highest temperature zone of a combustor wake ranged from approximately 1670 degrees F at leading and trailing edges to 1340 degrees F at midchord on the convex side of the blade. The maximum measured nozzle-guide-vane temperature of 1920degrees at the trailing edge occurred during a rapid acceleration from idle to rated take-off speed following which the tail-pipe gas temperature exceeded maximum allowable temperature by 125 degrees F.

  14. Transient Wave Envelope Elements for Wave Problems

    NASA Astrophysics Data System (ADS)

    Astley, R. J.

    1996-04-01

    A novel family of infinite wave envelope elements is described which can be used in conjunction with conventional finite elements to model the transient wave equation in unbounded regions. The elements are obtained by applying an inverse Fourier transformation to a mapped wave envelope formulation in the frequency domain. The discrete transient equations obtained in this way can be applied to two-dimensional and three-dimensional problems without restriction, being valid over a full range of excitation frequencies. The effectiveness and accuracy of the method is demonstrated in application to simple test cases which involve the calculation of transient sound fields generated by pulsating spheres and cylinders excited from rest in an unbounded region. Test solutions are compared to analytic solutions and to finite element solutions obtained by using large computational grids which extend beyond the region influenced by the transient disturbance.

  15. [Transient abnormal Q-waves].

    PubMed

    Godballe, C; Hoeck, H C; Sørensen, J A

    1990-01-01

    We present a case of transient abnormal Q-waves (TAQ) and a review of the literature. TAQ are defined as abnormal Q-waves, which disappear within ten days. They are most often seen in patients with ischemic heart disease (IHD) but are also seen in other conditions. Brief episodes of myocardial ischemia giving rise to reversible biochemical and ultrastructural myocardial changes, resulting in transient ECG changes, provide an accepted theory for the pathogenesis of TAO. Investigations have shown that the occurrence of exercise-induced TAQ may be a symptom of IHD. It is impossible to distinguish TAQ from Q-waves induced by myocardial infarction. Appearance of TAQ during exercise-testing frequently indicates IHD. PMID:2301045

  16. High-energy transients.

    PubMed

    Gehrels, Neil; Cannizzo, John K

    2013-06-13

    We present an overview of high-energy transients in astrophysics, highlighting important advances over the past 50 years. We begin with early discoveries of γ-ray transients, and then delve into physical details associated with a variety of phenomena. We discuss some of the unexpected transients found by Fermi and Swift, many of which are not easily classifiable or in some way challenge conventional wisdom. These objects are important insofar as they underscore the necessity of future, more detailed studies. PMID:23630376

  17. Transient nucleation in glasses

    NASA Technical Reports Server (NTRS)

    Kelton, K. F.

    1991-01-01

    Nucleation rates in condensed systems are frequently not at their steady state values. Such time dependent (or transient) nucleation is most clearly observed in devitrification studies of metallic and silicate glasses. The origin of transient nucleation and its role in the formation and stability of desired phases and microstructures are discussed. Numerical models of nucleation in isothermal and nonisothermal situations, based on the coupled differential equations describing cluster evolution within the classical theory, are presented. The importance of transient nucleation in glass formation and crystallization is discussed.

  18. [Transient epileptic amnesia].

    PubMed

    Muramatsu, Kazuhiro; Yoshizaki, Takahito

    2016-03-01

    Transient amnesia is one of common clinical phenomenon of epilepsy that are encountered by physicians. The amnestic attacks are often associated with persistent memory disturbances. Epilepsy is common among the elderly, with amnesia as a common symptom and convulsions relatively uncommon. Therefore, amnesia due to epilepsy can easily be misdiagnosed as dementia. The term 'transient epileptic amnesia (TEA)' was introduced in the early 1990s by Kapur, who highlighted that amnestic attacks caused by epilepsy can be similar to those occurring in 'transient global amnesia', but are distinguished by features brevity and recurrence. In 1998, Zeman et al. proposed diagnostic criteria for TEA.

  19. Gamma ray transients

    NASA Technical Reports Server (NTRS)

    Cline, Thomas L.

    1987-01-01

    The discovery of cosmic gamma ray bursts was made with systems designed at Los Alamos Laboratory for the detection of nuclear explosions beyond the atmosphere. HELIOS-2 was the first gamma ray burst instrument launched; its initial results in 1976, seemed to deepen the mystery around gamma ray transients. Interplanetary spacecraft data were reviewed in terms of explaining the behavior and source of the transients.

  20. Primary progressive aphasia and transient global amnesia

    PubMed Central

    Graff-Radford, Jonathan; Josephs, Keith A.

    2014-01-01

    Objective To report three patients with history of transient global amnesia who developed primary progressive aphasia. Patients Three patients presenting to the Neurology clinic with language complaints Setting Tertiary care center Results We describe three patients with a history of transient global amnesia who were subsequently diagnosed with primary progressive aphasia. All patients had recurrent attacks of transient global amnesia. The diagnoses of primary progressive aphasia were supported by speech pathology evaluations, neuropsychometric testing and imaging findings. PET scans, for example, revealed left posterior frontal hypometabolism in one patient, predominately left temporal-parietal hypometabolism in another while single-photon emission computed tomography demonstrated decreased perfusion in the anterior left temporal and frontal lobe in the third. Conclusions There may be a relationship between recurrent transient global amnesia and the development of primary progressive aphasia. PMID:22410450

  1. Distinction between persistent and transient infection in a bovine viral diarrhoea (BVD) control programme: appropriate interpretation of real-time RT-PCR and antigen-ELISA test results.

    PubMed

    Hanon, J-B; Van der Stede, Y; Antonissen, A; Mullender, C; Tignon, M; van den Berg, T; Caij, B

    2014-04-01

    Control of bovine viral diarrhoea (BVD) in Belgium is currently implemented on a voluntary basis at herd level and mainly relies on detection and culling of persistently infected (PI) animals. The present field study was conducted during the winter of 2010/2011 to assess the performances of diagnostic assays used in the testing scheme for BVD as proposed by the two Belgian regional laboratories. Individual blood samples were collected from 4972 animals, and individual samples from the same herd were pooled (maximum of 30 individual samples per pool) and screened for the presence of Bovine Viral Diarrhoea Virus (BVDV)-specific RNA using a commercial real-time RT-PCR test (ADIAGENE). Individual samples from positive pools were then tested in parallel with the same RT-PCR test and with an antigen-capture ELISA test (IDEXX) to detect viremic animals. This study demonstrated that individual results differed according to the type of assay used (P < 0.001): 140 animals (2.8%) were positive by RT-PCR and 72 (1.4%) by antigen-ELISA. A second blood sample was taken 40 days later from 74 PCR positive animals to detect persistent viremia: 17 (23%) of these were still PCR positive and considered to be PI and the 57 that no longer tested positive were assumed to be transiently infected (TI) animals. All PI animals were positive also by antigen-ELISA at both time points. Among TI animals, 10 (16%) were positive by antigen-ELISA at the first but none at the second sampling. A highly significant difference in cycle threshold (Ct ) values obtained by RT-PCR was observed between PI and TI animals. ROC analysis was performed to establish thresholds to confirm with high probability that an animal is PI, based on the result of RT-PCR test performed on a single individual blood sample.

  2. [THERAPY OF TRANSIENT LACTASE INSUFFICIENCY OF CHILDREN IN PECTORAL AGE].

    PubMed

    Marushko, Yu V; Iovitsa, T V

    2015-01-01

    Thus, we have discovered that the children of the first half-year of life have different degrees of severity of transient lactase insufficiency basing on the results of hydrogen respiratory test. It was set that the starting dose of enzyme lactase must depend on the degree of severity of displays of transient lactase insufficiency, taking into account the indexes of hydrogen respiratory test.

  3. Transient eddy current flow metering

    NASA Astrophysics Data System (ADS)

    Forbriger, J.; Stefani, F.

    2015-10-01

    Measuring local velocities or entire flow rates in liquid metals or semiconductor melts is a notorious problem in many industrial applications, including metal casting and silicon crystal growth. We present a new variant of an old technique which relies on the continuous tracking of a flow-advected transient eddy current that is induced by a pulsed external magnetic field. This calibration-free method is validated by applying it to the velocity of a spinning disk made of aluminum. First tests at a rig with a flow of liquid GaInSn are also presented.

  4. Regulatory Analysis of Reactivity Transients

    SciTech Connect

    Beyer, Carl E.; Clifford, Paul M.; Geelhood, Kenneth J.; Voglewede, John C.

    2009-08-01

    This paper will describe modifications made to the FRAPCON-3 and FRAPTRAN fuel performance codes and models that impact reactivity initiated accident (RIA) analyses. The modified models include an upper bound empirical and best estimate release models for fast transients, and a revised fuel failure model that accounts for ductile and brittle failure. Because experimental data exists for discrete test conditions, the codes and models are used to interpolate and to some extent, to extrapolate these test conditions. An upper bound empirical model for release is used to establish new recommended release fractions for long-lived and short lived (radioactive) isotopes for RIA events in Regulatory Guide 1.183. A best estimate release model is used in FRAPTRAN 1.4 based on grain boundary gas concentrations from FRAPCON-3.4 to predict release for RIA events. Code and model predictions will be compared to failure and release data from RIA tests to demonstrate accuracy.

  5. Calibration of acoustic transients.

    PubMed

    Burkard, Robert

    2006-05-26

    This article reviews the appropriate stimulus parameters (click duration, toneburst envelope) that should be used when eliciting auditory brainstem responses from mice. Equipment specifications required to calibrate these acoustic transients are discussed. Several methods of calibrating the level of acoustic transients are presented, including the measurement of peak equivalent sound pressure level (peSPL) and peak sound pressure level (pSPL). It is hoped that those who collect auditory brainstem response thresholds in mice will begin to use standardized methods of acoustic calibration, so that hearing thresholds across mouse strains obtained in different laboratories can more readily be compared.

  6. The Transient Universe

    NASA Astrophysics Data System (ADS)

    Shappee, Benjamin John

    When one looks at the night sky, one usually gets the impression of a static and constant universe. Quite apart from appearances, the sky is teeming with violent, variable, and transient events that shape our universe. These capricious objects are not only penetrating probes into physical conditions too extreme for earthbound laboratories, but they are also useful tools to measure the universe. In this dissertation, I investigate the observational and theoretical properties of three classes of transient/variable objects: thermonuclear supernovae, Cepheid variable stars, and active galactic nuclei.

  7. Transient combustion in hybrid rockets

    NASA Astrophysics Data System (ADS)

    Karabeyoglu, Mustafa Arif

    1998-09-01

    Hybrid rockets regained interest recently as an alternative chemical propulsion system due to their advantages over the solid and liquid systems that are currently in use. Development efforts on hybrids revealed two important problem areas: (1) low frequency instabilities and (2) slow transient response. Both of these are closely related to the transient behavior which is a poorly understood aspect of hybrid operation. This thesis is mainly involved with a theoretical study of transient combustion in hybrid rockets. We follow the methodology of identifying and modeling the subsystems of the motor such as the thermal lags in the solid, boundary layer combustion and chamber gasdynamics from a dynamic point of view. We begin with the thermal lag in the solid which yield the regression rate for any given wall heat flux variation. Interesting phenomena such as overshooting during throttling and the amplification and phase lead regions in the frequency domain are discovered. Later we develop a quasi-steady transient hybrid combustion model supported with time delays for the boundary layer processes. This is integrated with the thermal lag system to obtain the thermal combustion (TC) coupled response. The TC coupled system with positive delays generated low frequency instabilities. The scaling of the instabilities are in good agreement with actual motor test data. Finally, we formulate a gasdynamic model for the hybrid chamber which successfully resolves the filling/emptying and longitudinal acoustic behavior of the motor. The TC coupled system is later integrated to the gasdynamic model to obtain the overall response (TCG coupled system) of gaseous oxidizer motors with stiff feed systems. Low frequency instabilities were also encountered for the TCG coupled system. Apart from the transient investigations, the regression rate behavior of liquefying hybrid propellants such as solid cryogenic materials are also studied. The theory is based on the possibility of enhancement

  8. Classification of Transient Phenomena in Distribution System using wavelet Transform

    NASA Astrophysics Data System (ADS)

    Sedighi, Alireza

    2014-05-01

    An efficient procedure for classification of transient phenomena in distribution systems is proposed in this paper. The proposed method has been applied to classify some transient phenomena such as inrush current, load switching, capacitor switching and single phase to ground fault. The new scheme is based on wavelet transform algorithm. All of the events for feature extraction and test are simulated using Electro Magnetic Transient Program (EMTP). Results show high accuracy of proposed method.

  9. Laser-induced transient grating setup with continuously tunable period

    SciTech Connect

    Vega-Flick, A.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Khanolkar, A.; Abi Ghanem, M.; Boechler, N.; Alvarado-Gil, J. J.

    2015-12-15

    We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

  10. Transient neonatal zinc deficiency.

    PubMed

    Krieger, I; Alpern, B E; Cunnane, S C

    1986-06-01

    We report an infant who developed clinical manifestations of zinc deficiency during the first month of life although the diet was adequate for zinc and no other causes could be ascertained. The diagnosis was confirmed by low plasma-zinc concentrations and a positive response to zinc treatment. The fatty acid profile of plasma phospholipids was typical of zinc deficiency (ie, arachidonic acid was markedly decreased). The transient nature of this disorder was evident when no relapse occurred after cessation of zinc therapy and plasma-zinc and arachidonic acid concentrations remained normal. Several explanations for the development of transient neonatal zinc deficiency are offered. The observation demonstrates that occasional infants may have requirements for zinc that are beyond the intakes of the conventional RDA. PMID:3717070

  11. Reactor System Transient Code.

    1999-07-14

    RELAP3B describes the behavior of water-cooled nuclear reactors during postulated accidents or power transients, such as large reactivity excursions, coolant losses or pump failures. The program calculates flows, mass and energy inventories, pressures, temperatures, and steam qualities along with variables associated with reactor power, reactor heat transfer, or control systems. Its versatility allows one to describe simple hydraulic systems as well as complex reactor systems.

  12. Bright Transients discovered by PSST

    NASA Astrophysics Data System (ADS)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-04-01

    Seven bright transients have been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  13. Bright Transients discovered by PSST

    NASA Astrophysics Data System (ADS)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-03-01

    Seven bright transients have been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  14. Bright Transients discovered by PSST

    NASA Astrophysics Data System (ADS)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Young, D. R.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    Six bright transients have been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  15. Two Transients discovered by PSST

    NASA Astrophysics Data System (ADS)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Young, D. R.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    Two transients have been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  16. Advanced PFBC transient analysis

    SciTech Connect

    White, J.S.; Bonk, D.L.

    1997-05-01

    Transient modeling and analysis of advanced Pressurized Fluidized Bed Combustion (PFBC) systems is a research area that is currently under investigation by the US Department of Energy`s Federal Energy Technology Center (FETC). The object of the effort is to identify key operating parameters that affect plant performance and then quantify the basic response of major sub-systems to changes in operating conditions. PC-TRAX{trademark}, a commercially available dynamic software program, was chosen and applied in this modeling and analysis effort. This paper describes the development of a series of TRAX-based transient models of advanced PFBC power plants. These power plants burn coal or other suitable fuel in a PFBC, and the high temperature flue gas supports low-Btu fuel gas or natural gas combustion in a gas turbine topping combustor. When it is utilized, the low-Btu fuel gas is produced in a bubbling bed carbonizer. High temperature, high pressure combustion products exiting the topping combustor are expanded in a modified gas turbine to generate electrical power. Waste heat from the system is used to raise and superheat steam for a reheat steam turbine bottoming cycle that generates additional electrical power. Basic control/instrumentation models were developed and modeled in PC-TRAX and used to investigate off-design plant performance. System performance for various transient conditions and control philosophies was studied.

  17. ON DETECTING TRANSIENT PHENOMENA

    SciTech Connect

    Belanger, G.

    2013-08-10

    Transient phenomena are interesting and potentially highly revealing of details about the processes under observation and study that could otherwise go unnoticed. It is therefore important to maximize the sensitivity of the method used to identify such events. In this article, we present a general procedure based on the use of the likelihood function for identifying transients which is particularly suited for real-time applications because it requires no grouping or pre-processing of the data. The method makes use of all the information that is available in the data throughout the statistical decision-making process, and is suitable for a wide range of applications. Here we consider those most common in astrophysics, which involve searching for transient sources, events or features in images, time series, energy spectra, and power spectra, and demonstrate the use of the method in the case of a weak X-ray flare in a time series and a short-lived quasi-periodic oscillation in a power spectrum. We derive a fit statistic that is ideal for fitting arbitrarily shaped models to a power density distribution, which is of general interest in all applications involving periodogram analysis.

  18. Comparison of Single-Event Transients Induced in an Operational Amplifier (LM124) by Pulsed Laser Light and a Broad Beam of Heavy Ions

    NASA Technical Reports Server (NTRS)

    Buchner, Steve; McMorrow, Dale; Poivey, Christian; Howard, James, Jr.; Pease, Rom; Savage, Mark; Boulghassoul, Younis; Massengill, Lloyd

    2003-01-01

    A comparison of transients from heavy-ion and pulsed-laser testing shows good agreement for many different voltage configurations. The agreement is illustrated by comparing directly individual transients and plots of transient amplitude versus width.

  19. Transient triggering of near and distant earthquakes

    USGS Publications Warehouse

    Gomberg, J.; Blanpied, M.L.; Beeler, N.M.

    1997-01-01

    We demonstrate qualitatively that frictional instability theory provides a context for understanding how earthquakes may be triggered by transient loads associated with seismic waves from near and distance earthquakes. We assume that earthquake triggering is a stick-slip process and test two hypotheses about the effect of transients on the timing of instabilities using a simple spring-slider model and a rate- and state-dependent friction constitutive law. A critical triggering threshold is implicit in such a model formulation. Our first hypothesis is that transient loads lead to clock advances; i.e., transients hasten the time of earthquakes that would have happened eventually due to constant background loading alone. Modeling results demonstrate that transient loads do lead to clock advances and that the triggered instabilities may occur after the transient has ceased (i.e., triggering may be delayed). These simple "clock-advance" models predict complex relationships between the triggering delay, the clock advance, and the transient characteristics. The triggering delay and the degree of clock advance both depend nonlinearly on when in the earthquake cycle the transient load is applied. This implies that the stress required to bring about failure does not depend linearly on loading time, even when the fault is loaded at a constant rate. The timing of instability also depends nonlinearly on the transient loading rate, faster rates more rapidly hastening instability. This implies that higher-frequency and/or longer-duration seismic waves should increase the amount of clock advance. These modeling results and simple calculations suggest that near (tens of kilometers) small/moderate earthquakes and remote (thousands of kilometers) earthquakes with magnitudes 2 to 3 units larger may be equally effective at triggering seismicity. Our second hypothesis is that some triggered seismicity represents earthquakes that would not have happened without the transient load (i

  20. Workshop on Radio Transients

    NASA Astrophysics Data System (ADS)

    Croft, Steve; Gaensler, Bryan

    2012-04-01

    abstract-type="normal">SummaryWe are entering a new era in the study of variable and transient radio sources. This workshop discussed the instruments and the strategies employed to study those sources, how they are identified and classified, how results from different surveys can be compared, and how radio observations tie in with those at other wavelengths. The emphasis was on learning what common ground there is between the plethora of on-going projects, how methods and code can be shared, and how best practices regarding survey strategy could be adopted. The workshop featured the four topics below. Each topic commenced with a fairly brief introductory talk, which then developed into discussion. By way of preparation, participants had been invited to upload and discuss one slide per topic to a wiki ahead of the workshop. 1. Telescopes, instrumentation and survey strategy. New radio facilities and on-going projects (including upgrades) are both studying the variability of the radio sky, and searching for transients. The discussion first centred on the status of those facilities, and on projects with a time-domain focus, both ongoing and planned, before turning to factors driving choices of instrumentation, such as phased array versus single pixel feeds, the field of view, spatial and time resolution, frequency and bandwidth, depth, area, and cadence of the surveys. 2. Detection, pipelines, and classification. The workshop debated (a) the factors that influence decisions to study variability in the (u,v) plane, in images, or in catalogues, (b) whether, and how much, pipeline code could potentially be shared between one project and another, and which software packages are best for different approaches, (c) how data are stored and later accessed, and (d) how transients and variables are defined and classified. 3. Statistics, interpretation, and synthesis. It then discussed how (i) the choice of facility and strategy and (ii) detection and classification schemes

  1. Thermal transient anemometer

    DOEpatents

    Bailey, James L.; Vresk, Josip

    1989-01-01

    A thermal transient anemometer having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe.

  2. Thermal transient anemometer

    DOEpatents

    Bailey, J.L.; Vresk, J.

    1989-07-18

    A thermal transient anemometer is disclosed having a thermocouple probe which is utilized to measure the change in temperature over a period of time to provide a measure of fluid flow velocity. The thermocouple probe is located in the fluid flow path and pulsed to heat or cool the probe. The cooling of the heated probe or the heating of the cooled probe from the fluid flow over a period of time is measured to determine the fluid flow velocity. The probe is desired to be locally heated near the tip to increase the efficiency of devices incorporating the probe. 12 figs.

  3. The Rapid Transient Surveyor

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Tonry, John; Wright, Shelley; Tully, R. Brent; Lu, Jessica R.; Takamiya, Marianne Y.; Hunter, Lisa

    2016-01-01

    The next decade of astronomy will be dominated by large area surveys (see the detailed discussion in the Astro-2010 Decadal survey and NRC's recent OIR System Report). Ground-based optical transient surveys, e.g., LSST, ZTF and ATLAS and space-based exoplanet, supernova, and lensing surveys such as TESS and WFIRST will join the Gaia all-sky astrometric survey in producing a flood of data that will enable leaps in our understanding of the universe. There is a critical need for further characterization of these discoveries through high angular resolution images, deeper images, spectra, or observations at different cadences or periods than the main surveys. Such follow-up characterization must be well matched to the particular surveys, and requires sufficient additional observing resources and time to cover the extensive number of targets.We describe plans for the Rapid Transient Surveyor (RTS), a permanently mounted, rapid-response, high-cadence facility for follow-up characterization of transient objects on the U. of Hawai'i 2.2-m telescope on Maunakea. RTS will comprise an improved robotic laser adaptive optics system, based on the prototype Robo-AO system (formerly at the Palomar 1.5-m and now at the Kitt Peak 2.2-m telescope), with simultaneous visible and near-infrared imagers as well as a near-infrared integral field spectrograph (R~100, λ = 850 - 1830 nm, 0.15″ spaxels, 8.7″×6.0″ FoV). RTS will achieve an acuity of ~0.07″ in visible wavelengths and < 0.16″ in the near infrared leading to an increase of the infrared point-source sensitivity against the sky background by a factor of ~9, crucial for efficient near-infrared spectroscopy.RTS will allow us to map the dark matter distribution in the z < 0.1 local universe with ten times better accuracy and precision than previous experiments. ATLAS will discover several thousand SNIae per year, measuring SNIa peak brightness, and decline rates, while RTS will measure reddening by dust, confirm SN type and

  4. Steady and transient regimes in hydropower plants

    NASA Astrophysics Data System (ADS)

    Gajic, A.

    2013-12-01

    Hydropower plant that has been in operation for about 30 years has to be reconstructed. They have already installed 12 Kaplan turbines, the largest in the world at that time. The existing CAM relationship was determined based on hydraulic model tests and checked by efficiency on-site tests. It was also tested based on turbine bearing vibrations. In order to discover vibrations and long cracks on stay vanes detailed on-site measurements were performed. Influence of the modification of the trailing edges on the dynamic stresses of the stay vanes is also shown. In order to improve power output transient regimes were analyzed, both experimentally and numerically. Reversible hydropower plant, a pioneer in Europe since it was the first Pump storage power plant constructed with the highest head pump-turbines in the world. Analyses of transient regimes discover some problems with S-shaped characteristics coupled with non-symmetrical penstock.

  5. Transient Microphonic Effects In Superconducting Cavities

    SciTech Connect

    Thomas Powers; G. Davis; Lawrence King

    2005-07-10

    A number of experiments were performed on an installed and operational 5-cell CEBAF cavity to determine the minimum time required to reestablish stable gradient after a cavity window arc trip. Once it was determined that gradient could be reestablished within 10 ms by applying constant power RF signal in and a voltage controlled Oscillator-phase locked loop based system (VCO-PLL), a second experiment was performed to determine if stable gradient could be reestablished using a fixed frequency RF system with a simple gradient based closed loop control system. During this test, instabilities were observed in the cavity forward power signal, which were determined to be microphonic in nature. These microphonic effects were quantified using a cavity resonance monitor and a VCO{_}PLL RF system. Two types of microphonic effects were observed depending on the type of arc event. If the arc occurred in the vacuum space between the warm and cold windows, the transient frequency shift was about 75 Hz peak-to-peak. If the arc occurred on the cavity side of the cold window the transient frequency shift was about 400 Hz peak-to-peak. The background microphonics level for the tested cavity was approximately 30 Hz peak-to-peak. Experimental results, analysis of the resultant klystron power transients, the decay time of the transients, and the implications with respect to fast reset algorithms will be presented.

  6. Characterizing Nanoscale Transient Communication.

    PubMed

    Chen, Yifan; Anwar, Putri Santi; Huang, Limin; Asvial, Muhamad

    2016-04-01

    We consider the novel paradigm of nanoscale transient communication (NTC), where certain components of the small-scale communication link are physically transient. As such, the transmitter and the receiver may change their properties over a prescribed lifespan due to their time-varying structures. The NTC systems may find important applications in the biomedical, environmental, and military fields, where system degradability allows for benign integration into life and environment. In this paper, we analyze the NTC systems from the channel-modeling and capacity-analysis perspectives and focus on the stochastically meaningful slow transience scenario, where the coherence time of degeneration Td is much longer than the coding delay Tc. We first develop novel and parsimonious models to characterize the NTC channels, where three types of physical layers are considered: electromagnetism-based terahertz (THz) communication, diffusion-based molecular communication (DMC), and nanobots-assisted touchable communication (TouchCom). We then revisit the classical performance measure of ϵ-outage channel capacity and take a fresh look at its formulations in the NTC context. Next, we present the notion of capacity degeneration profile (CDP), which describes the reduction of channel capacity with respect to the degeneration time. Finally, we provide numerical examples to demonstrate the features of CDP. To the best of our knowledge, the current work represents a first attempt to systematically evaluate the quality of nanoscale communication systems deteriorating with time.

  7. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

    NASA Astrophysics Data System (ADS)

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

    2016-03-01

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on

  8. Cable coupling lightning transient qualification

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    Simulated lightning strike testing of instrumentation cabling on the redesigned solid rocket motor was performed. Testing consisted of subjecting the lightning evaluation test article to simulated lightning strikes and evaluating the effects of instrumentation cable transients on cables within the system tunnel. The maximum short-circuit current induced onto a United Space Boosters, Inc., operational flight cable within the systems tunnel was 92 A, and the maximum induced open-circuit voltage was 316 V. These levels were extrapolated to the worst-case (200 kA) condition of NASA specification NSTS 07636 and were also scaled to full-scale redesigned solid rocket motor dimensions. Testing showed that voltage coupling to cables within the systems tunnel can be reduced 40 to 90 dB and that current coupling to cables within the systems tunnel can be reduced 30 to 70 dB with the use of braided metallic sock shields around cables that are external to the systems tunnel. Testing also showed that current and voltage levels induced onto cables within the systems tunnel are partially dependant on the cables' relative locations within the systems tunnel. Results of current injections to the systems tunnel indicate that the dominant coupling mode on cables within the systems tunnel is not from instrumentation cables but from coupling through the systems tunnel cover seam apertures. It is recommended that methods of improving the electrical bonding between individual sections of the systems tunnel covers be evaluated. Further testing to better characterize redesigned solid rocket motor cable coupling effects as an aid in developing methods to reduce coupling levels, particularly with respect to cable placement within the systems tunnel, is also recommended.

  9. [THERAPY OF TRANSIENT LACTASE INSUFFICIENCY OF CHILDREN IN PECTORAL AGE].

    PubMed

    Marushko, Yu V; Iovitsa, T V

    2015-01-01

    Thus, we have discovered that the children of the first half-year of life have different degrees of severity of transient lactase insufficiency basing on the results of hydrogen respiratory test. It was set that the starting dose of enzyme lactase must depend on the degree of severity of displays of transient lactase insufficiency, taking into account the indexes of hydrogen respiratory test. PMID:26118050

  10. Nordic Symposium on Analysis of Electromagnetic Transient Phenomena Using EMTP, part 2

    NASA Astrophysics Data System (ADS)

    Jokinen, Tapani

    The Electromagnetic Transients Program (EMTP) is a computer program used to simulate electromagnetic, electromechanical, and control system transients on multiphase electric power systems. Section headings in this volume include the following: Case Studies for Electromagnetic Transients; Transformers - Section 6 from EMTP Theory Book, Second Edition; What Is Needed In Transformer Representations; and Transformer Inrush Current, Test Case 1.

  11. The joy of transient chaos

    SciTech Connect

    Tél, Tamás

    2015-09-15

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  12. The joy of transient chaos

    NASA Astrophysics Data System (ADS)

    Tél, Tamás

    2015-09-01

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  13. The Zwicky Transient Facility

    NASA Astrophysics Data System (ADS)

    Kulkarni, Shrinivas R.

    2016-01-01

    The Zwicky Transient Facility (ZTF) has been designed with a singular focus: a systematic exploration of the night sky at a magnitude level well suited for spectral classification and follow up with the existing class of 4-m to 10-m class telescopes. ZTF is the successor to the Palomar Transient Factory (PTF). The discovery engine for ZTF is a 47 square degree camera (realized through 16 e2V monolithic CCDs) that fills the entire focal plane of the 48-inch Oschin telescope of the Palomar Observatory. Single 30-s epoch sensitivity is about 20.5 in g and R bands. The Infarared Processing & Analysis Center (IPAC) is the data center for ZTF. ZTF is a public-private partnership with equal contributions from a consortium of world-wide partners and an NSF MSIP grant. Forty percent of ZTF time is set aside for two major community surveys: a 3-day cadence survey of high latitudes (to mimic LSST) and a time domain survey of the entire Northern Galactic plane. We expect first light in February 2017 and begin a 3-year survey starting summer of 2017. The first year will be spent on building up deep reference images of the sky (a must for transient surveys). During the second year IPAC will deliver near archival quality photometric products within 12 hours of observations. By comparison to reference images photometric alerts will be sent out. Year 3 will see the near real-time release of image differencing products. A Community Science Advisory Committee (CSAC), chaired by S. Ridgway (NOAO), has been set up to both advise the PI and to ensure that the US community's interests are well served. Astronomers interested in getting a head start on ZTF may wish to peruse the data releases from PTF. Young people (or young at heart) may wish to attend the annual summer school on PTF/ZTF (August, Caltech campus). The Principal Investigator (PI) for the project is S. Kulkarni and the Project Scientist is Eric Bellm.For further details please consult http://www.ptf.caltech.edu/ztf

  14. Transient complex peroxisomal interactions

    PubMed Central

    Bonekamp, Nina A.; Schrader, Michael

    2012-01-01

    Mitochondria and peroxisomes are ubiquitous subcellular organelles that fulfill essential metabolic functions, rendering them indispensable for human development and health. Both are highly dynamic organelles that can undergo remarkable changes in morphology and number to accomplish cellular needs. While mitochondrial dynamics are also regulated by frequent fusion events, the fusion of mature peroxisomes in mammalian cells remained a matter of debate. In our recent study, we clarified systematically that there is no complete fusion of mature peroxisomes analogous to mitochondria. Moreover, in contrast to key division components such as DLP1, Fis1 or Mff, mitochondrial fusion proteins were not localized to peroxisomes. However, we discovered and characterized novel transient, complex interactions between individual peroxisomes which may contribute to the homogenization of the often heterogeneous peroxisomal compartment, e.g., by distribution of metabolites, signals or other “molecular information” via interperoxisomal contact sites. PMID:23336019

  15. Transient infrared transmission spectroscopy

    SciTech Connect

    Jones, R.W.; McClelland, J.F. )

    1990-10-15

    Transient infrared transmission spectroscopy is a new method that can acquire analytically useful transmission spectra from moving, optically thick solids. No sample preparation is required. The spectra are of sufficient quality for accurate quantitative compositional analysis. The method works by the creation of a thin, short-lived, chilled layer at the sample surface. Blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the chilled layer, so the transmission spectrum of the layer is superimposed on the observed thermal emission. Spectra of polycarbonate, beeswax, and copolymers of methyl and butyl methacrylate are presented. Compositional analysis of the methacrylate copolymers with a standard error or prediction of only 0.87 mol % is demonstrated.

  16. Transient infrared transmission spectroscopy.

    PubMed

    Jones, R W; McClelland, J F

    1990-10-15

    Transient infrared transmission spectroscopy is a new method that can acquire analytically useful transmission spectra from moving, optically thick solids. No sample preparation is required. The spectra are of sufficient quality for accurate quantitative compositional analysis. The method works by the creation of a thin, short-lived, chilled layer at the sample surface. Blackbody-like thermal emission from the bulk of the sample is selectively absorbed as it passes through the chilled layer, so the transmission spectrum of the layer is superimposed on the observed thermal emission. Spectra of polycarbonate, beeswax, and copolymers of methyl and butyl methacrylate are presented. Compositional analysis of the methacrylate copolymers with a standard error of prediction of only 0.87 mol % is demonstrated.

  17. Blade loss transient dynamic analysis of turbomachinery

    NASA Technical Reports Server (NTRS)

    Stallone, M. J.; Gallardo, V.; Storace, A. F.; Bach, L. J.; Black, G.; Gaffney, E. F.

    1982-01-01

    This paper reports on work completed to develop an analytical method for predicting the transient non-linear response of a complete aircraft engine system due to the loss of a fan blade, and to validate the analysis by comparing the results against actual blade loss test data. The solution, which is based on the component element method, accounts for rotor-to-casing rubs, high damping and rapid deceleration rates associated with the blade loss event. A comparison of test results and predicted response show good agreement except for an initial overshoot spike not observed in test. The method is effective for analysis of large systems.

  18. Continuation of surge life of transient voltage suppressor

    NASA Technical Reports Server (NTRS)

    Clark, O. M.

    1977-01-01

    Efforts expended in testing, analyzing and the development of a meaningful definition of the mean number of peak pulses before failure (mp2bf) levels of a family of transient voltage suppressor devices were documented. Tests were done to determine the ability of the transient suppressor to effectively and reliably protect against severe short term, millisecond range, and transient voltages of the types resulting from inductive load switching and induced lightning. Existing pulse testing instrumentation was utilized, interfaced to an automatic sequencing test rack accommodating up to 50 devices. Tests were performed in step stress increments of 25% beginning at 25% and extending thru 100% rated I(pp) for each voltage category. The four voltage types test were the 6.8V, 33V, 91V, and 190V. Engineering efforts addressed the problem of improving the reliability of the 190V types.

  19. Summer 1993 Transient Student Report.

    ERIC Educational Resources Information Center

    Kent State Univ., Warren, OH. Office of Institutional Research.

    A study was conducted by the Trumbull Campus (TC) of Kent State University, in Ohio, to determine the motivations, objectives, and level of satisfaction of transient students, or students pursuing a degree at another institution but enrolled in courses at TC. Surveys were mailed to 50 transient students enrolled in summer 1993, with completed…

  20. Transient catalytic combustor model

    NASA Technical Reports Server (NTRS)

    Tien, J. S.

    1981-01-01

    A quasi-steady gas phase and thermally thin substrate model is used to analyze the transient behavior of catalytic monolith combustors in fuel lean operation. The combustor response delay is due to the substrate thermal inertia. Fast response is favored by thin substrate, short catalytic bed length, high combustor inlet and final temperatures, and small gas channel diameters. The calculated gas and substrate temperature time history at different axial positions provides an understanding of how the catalytic combustor responds to an upstream condition change. The computed results also suggest that the gas residence times in the catalytic bed in the after bed space are correlatable with the nondimensional combustor response time. The model also performs steady state combustion calculations; and the computed steady state emission characteristics show agreement with available experimental data in the range of parameters covered. A catalytic combustor design for automotive gas turbine engine which has reasonably fast response ( 1 second) and can satisfy the emission goals in an acceptable total combustor length is possible.

  1. Transient dynamics of a flexible rotor with squeeze film dampers

    NASA Technical Reports Server (NTRS)

    Buono, D. F.; Schlitzer, L. D.; Hall, R. G., III; Hibner, D. H.

    1978-01-01

    A series of simulated blade loss tests are reported on a test rotor designed to operate above its second bending critical speed. A series of analyses were performed which predicted the transient behavior of the test rig for each of the blade loss tests. The scope of the program included the investigation of transient rotor dynamics of a flexible rotor system, similar to modern flexible jet engine rotors, both with and without squeeze film dampers. The results substantiate the effectiveness of squeeze film dampers and document the ability of available analytical methods to predict their effectiveness and behavior.

  2. Model for transient creep of southeastern New Mexico rock salt

    SciTech Connect

    Herrmann, W; Wawersik, W R; Lauson, H S

    1980-11-01

    In a previous analysis, existing experimental data pertaining to creep tests on rock salt from the Salado formation of S.E. New Mexico were fitted to an exponential transient creep law. While very early time portions of creep strain histories were not fitted very well for tests at low temperatures and stresses, initial creep rates in particular generally being underestimated, the exponential creep law has the property that the transient creep strain approaches a finite limit with time, and is therefore desirable from a creep modelling point of view. In this report, an analysis of transient creep is made. It is found that exponential transient creep can be related to steady-state creep through a universal creep curve. The resultant description is convenient for creep analyses where very early time behavior is not important.

  3. Tool and method for the theremal transient evaluation of packages

    NASA Astrophysics Data System (ADS)

    Szekely, Vladimir; Rencz, Marta; Courtois, Bernard

    1999-10-01

    This paper presents a new concept for the thermal transient measurement of IC packages. The TTMK thermal transient test kit described here consists of a test chip, a dedicated software running on a PC and a special cable connecting the PC to the IC package which encapsulates the test chip. The function of the thermal transient test equipment is realized partly by the test chip itself and partly by the measuring software. The software performs both the control of the measurements and the evaluation of the results. The output of the evaluation software may be a compact model network or the structure function describing the properties of the heat conduction path. The use of the TTMK kit and the capabilities of the evaluation software are presented in this paper.

  4. Aeroelastic Modeling of a Nozzle Startup Transient

    NASA Technical Reports Server (NTRS)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  5. Transient studies of G-induced capillary dryout and rewet

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1995-01-01

    A transient, one-dimensional numerical code is developed to model the liquid motion in an axial groove with square cross section. Axial variation in liquid level, shear stress and heat transfer between the groove wall and the liquid, evaporation and transient body forces are accounted for in the model. Dryout and rewet of the groove are allowed; the front location is determined numerically using conservation of mass and linear extrapolation. Several numerical test results are presented and discussed.

  6. Transient failure behavior of HT9

    SciTech Connect

    Huang, F.H.

    1994-07-01

    Alloy HT9 has-been chosen as candidate materials for fast and fusion reactor applications because the.material exhibits excellent resistance to void swelling. However, ferritic alloys are known to undergo a ductile-brittle transition as the test temperature is decreased. This inherent problem has limited their applications to reactor component materials subjected to low neutron exposures. Despite the ductile-brittle transition problem, results show that the materials exhibit superior resistance to fracture under very high neutron fluences at irradiation temperatures above 380C. Results also show that the transient behavior for HT9 cladding specimens taken from the fuel column region and cladding taken from outside the fuel column or unirradiated cladding are the same. HT9 cladding maintained its transient strength with irradiation to a fluence of 9 {times} 10{sup 22} n/cm{sup 2} (E > 0.1 MeV).

  7. Transient upsets in microprocessor controllers

    NASA Technical Reports Server (NTRS)

    Glaser, R. E.; Masson, G. M.

    1981-01-01

    The modeling and analysis of transient faults in microprocessor based controllers are discussed. Such controllers typically consist of a microprocessor, read only memory storing and application program, random access memory for data storage, and input/output devices for external communications. The effects of transient faults on the performance of the controller are reviewed. An instruction level perspective of performance is taken which is the basis of a useful high level program state description of the microprocessor controller. A transition matrix is defined which determines the controller's response to transient fault arrivals.

  8. Transient overvoltages on cable sheaths

    NASA Astrophysics Data System (ADS)

    Dabringhaus, H. G.

    1983-08-01

    Transient overvoltage on the sheaths of high voltage cables with single point sheath earthing or cross bonding of the cable sheaths involve danger for the cable and the joints. The investigations of transient overvoltages in the case of a switching operation on a 110 kV single core oil filled cable with single sided sheath earthing are reported. A comparison between measured transient voltage variations and those calculated with the help of a traveling wave analyzer program shows very good agreement. The investigations showed that with single point sheath earthing, the unearthed sheath end ought to be protected against overvoltages.

  9. Endotoxin Deactivation by Transient Acidification

    PubMed Central

    Ribeiro, Melina M.; Xu, Xiumin; Klein, Dagmar; Kenyon, Norma S; Ricordi, Camillo; Felipe, Maria Sueli S.; Pastori, Ricardo L.

    2015-01-01

    Recombinant proteins are an important tool for research and therapeutic applications. Therapeutic proteins have been delivered to several cell types and tissues and might be used to improve the outcome of the cell transplantation. Recombinant proteins are propagated in bacteria, which will contaminate them with the lypopolysacharide-endotoxin found in the outer bacterial membrane. Endotoxin could interfere with in vitro biological assays and is the major pathological factor, which must be removed or inactivated before in vivo administration. Here we describe a one-step protocol in which the endotoxin activity on recombinant proteins is remarkably reduced by transient exposure to acidic conditions. Maximum endotoxin deactivation occurs at acidic pH below their respective isoelectric point (pI). This method does not require additional protein purification or separation of the protein from the endotoxin fraction. The endotoxin level was measured both in vitro and in vivo. For in vitro assessment we have utilized Limulus Amebocyte Lysate method for in vivo the pyrogenic test. We have tested the above-mentioned method with 5 different recombinant proteins including a monoclonal antibody clone 5c8 against CD154 produced by hybridomas. More than 99% of endotoxin was deactivated in all of the proteins, the recovery of the protein after deactivation varied between maximum 72.9 and minimum 46.8%. The anti CD154 clone 5c8 activity remained unchanged as verified by the measurement of binding capability to activated lymphocytes. Furthermore, the effectiveness of this method was not significantly altered by urea, commonly used in protein purification. This procedure provides a simple and cost-efficient way to reduce the endotoxin activity in antibodies and recombinant proteins. PMID:20412635

  10. Transient ischemic attack

    MedlinePlus

    ... the symptoms: You will likely have a head CT scan or brain MRI . A stroke may show changes on these tests, but TIAs will not. You may have an angiogram , CT angiogram, or MR angiogram to see which blood ...

  11. Transient nucleation in condensed systems

    NASA Technical Reports Server (NTRS)

    Kelton, K. F.; Greer, A. L.; Thompson, C. V.

    1983-01-01

    Using classical nucleation theory we consider transient nucleation occurring in a one-component, condensed system under isothermal conditions. We obtain an exact closed-form expression for the time dependent cluster populations. In addition, a more versatile approach is developed: a numerical simulation technique which models directly the reactions by which clusters are produced. This simulation demonstrates the evolution of cluster populations and nucleation rate in the transient regime. Results from the simulation are verified by comparison with exact analytical solutions for the steady state. Experimental methods for measuring transient nucleation are assessed, and it is demonstrated that the observed behavior depends on the method used. The effect of preexisting cluster distributions is studied. Previous analytical and numerical treatments of transient nucleation are compared to the solutions obtained from the simulation. The simple expressions of Kashchiev are shown to give good descriptions of the nucleation behavior.

  12. The Palomar Transient Factory: System Overview, Performance, and First Results

    NASA Astrophysics Data System (ADS)

    Law, Nicholas M.; Kulkarni, Shrinivas R.; Dekany, Richard G.; Ofek, Eran O.; Quimby, Robert M.; Nugent, Peter E.; Surace, Jason; Grillmair, Carl C.; Bloom, Joshua S.; Kasliwal, Mansi M.; Bildsten, Lars; Brown, Tim; Cenko, S. Bradley; Ciardi, David; Croner, Ernest; Djorgovski, S. George; van Eyken, Julian; Filippenko, Alexei V.; Fox, Derek B.; Gal-Yam, Avishay; Hale, David; Hamam, Nouhad; Helou, George; Henning, John; Howell, D. Andrew; Jacobsen, Janet; Laher, Russ; Mattingly, Sean; McKenna, Dan; Pickles, Andrew; Poznanski, Dovi; Rahmer, Gustavo; Rau, Arne; Rosing, Wayne; Shara, Michael; Smith, Roger; Starr, Dan; Sullivan, Mark; Velur, Viswa; Walters, Richard; Zolkower, Jeff

    2009-12-01

    The Palomar Transient Factory (PTF) is a fully-automated, wide-field survey aimed at a systematic exploration of the optical transient sky. The transient survey is performed using a new 8.1 square degree camera installed on the 48 inch Samuel Oschin telescope at Palomar Observatory; colors and light curves for detected transients are obtained with the automated Palomar 60 inch telescope. PTF uses 80% of the 1.2 m and 50% of the 1.5 m telescope time. With an exposure of 60 s the survey reaches a depth of mg' ≈ 21.3 and mR ≈ 20.6 (5σ, median seeing). Four major experiments are planned for the five-year project: (1) a 5 day cadence supernova search; (2) a rapid transient search with cadences between 90 s and 1 day (3) a search for eclipsing binaries and transiting planets in Orion; and (4) a 3π sr deep H-alpha survey. PTF provides automatic, real-time transient classification and follow-up, as well as a database including every source detected in each frame. This paper summarizes the PTF project, including several months of on-sky performance tests of the new survey camera, the observing plans, and the data reduction strategy. We conclude by detailing the first 51 PTF optical transient detections, found in commissioning data.

  13. Capture-recapture survival models taking account of transients

    USGS Publications Warehouse

    Pradel, R.; Hines, J.E.; Lebreton, J.D.; Nichols, J.D.

    1997-01-01

    The presence of transient animals, common enough in natural populations, invalidates the estimation of survival by traditional capture- recapture (CR) models designed for the study of residents only. Also, the study of transit is interesting in itself. We thus develop here a class of CR models to describe the presence of transients. In order to assess the merits of this approach we examme the bias of the traditional survival estimators in the presence of transients in relation to the power of different tests for detecting transients. We also compare the relative efficiency of an ad hoc approach to dealing with transients that leaves out the first observation of each animal. We then study a real example using lazuli bunting (Passerina amoena) and, in conclusion, discuss the design of an experiment aiming at the estimation of transience. In practice, the presence of transients is easily detected whenever the risk of bias is high. The ad hoc approach, which yields unbiased estimates for residents only, is satisfactory in a time-dependent context but poorly efficient when parameters are constant. The example shows that intermediate situations between strict 'residence' and strict 'transience' may exist in certain studies. Yet, most of the time, if the study design takes into account the expected length of stay of a transient, it should be possible to efficiently separate the two categories of animals.

  14. Differential Diagnosis of Transient Amnesia

    PubMed Central

    Croft, P. B.; Heathfield, K. W. G.; Swash, M.

    1973-01-01

    In a group of 39 consecutive patients attending neurological clinics with transient amnesia patients with transient global amnesia formed the largest group; others suffered from epilepsy, migraine, temporal lobe encephalitis, or psychogenic fugues. In most cases the clinical features suggested the aetiology, but an electroencephalogram recorded as soon after the attack as possible may help in distinguishing amnesia due to temporal lobe epilepsy. PMID:4758521

  15. Transient Tsunamis in Lakes

    NASA Astrophysics Data System (ADS)

    Couston, L.; Mei, C.; Alam, M.

    2013-12-01

    A large number of lakes are surrounded by steep and unstable mountains with slopes prone to failure. As a result, landslides are likely to occur and impact water sitting in closed reservoirs. These rare geological phenomena pose serious threats to dam reservoirs and nearshore facilities because they can generate unexpectedly large tsunami waves. In fact, the tallest wave experienced by contemporary humans occurred because of a landslide in the narrow bay of Lituya in 1958, and five years later, a deadly landslide tsunami overtopped Lake Vajont's dam, flooding and damaging villages along the lakefront and in the Piave valley. If unstable slopes and potential slides are detected ahead of time, inundation maps can be drawn to help people know the risks, and mitigate the destructive power of the ensuing waves. These maps give the maximum wave runup height along the lake's vertical and sloping boundaries, and can be obtained by numerical simulations. Keeping track of the moving shorelines along beaches is challenging in classical Eulerian formulations because the horizontal extent of the fluid domain can change over time. As a result, assuming a solid slide and nonbreaking waves, here we develop a nonlinear shallow-water model equation in the Lagrangian framework to address the problem of transient landslide-tsunamis. In this manner, the shorelines' three-dimensional motion is part of the solution. The model equation is hyperbolic and can be solved numerically by finite differences. Here, a 4th order Runge-Kutta method and a compact finite-difference scheme are implemented to integrate in time and spatially discretize the forced shallow-water equation in Lagrangian coordinates. The formulation is applied to different lake and slide geometries to better understand the effects of the lake's finite lengths and slide's forcing mechanism on the generated wavefield. Specifically, for a slide moving down a plane beach, we show that edge-waves trapped by the shoreline and free

  16. Transient Heat Transfer in TCAP Coils

    SciTech Connect

    Steimke, J.L.

    1999-03-09

    The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would have been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0" tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed, quickly

  17. Transient Heat Transfer in TCAP Coils

    SciTech Connect

    Steimke, J.L.

    1999-03-09

    The Thermal Cycling Absorption Process (TCAP) is used to separate isotopes of hydrogen. TCAP involves passing a stream of mixed hydrogen isotopes through palladium deposited on kieselguhr (Pd/k) while cycling the temperature of the Pd/k. Kieselguhr is a silica mineral also called diatomite. To aid in the design of a full scale facility, the Thermal Fluids Laboratory was used by the Chemical and Hydrogen Technology Section to compare the heat transfer properties of three different configurations of stainless steel coils containing kieselguhr and helium. Testing of coils containing Pd/k and hydrogen isotopes would have been more prototypical but would have been too expensive. Three stainless steel coils filled with kieselguhr were tested; one made from 2.0 inch diameter tubing, one made from 2.0 inch diameter tubing with foam copper embedded in the kieselguhr and one made from 1.25 inch diameter tubing. It was known prior to testing that increasing the tubing diameter from 1.25 inch to 2.0 inch would slow the rate of temperature change. The primary purpose of the testing was to measure to what extent the presence of copper foam in a 2.0 tubing coil would compensate for the effect of larger diameter. Each coil was connected to a pressure gage and the coil was evacuated and backfilled with helium gas. Helium was used instead of a mixture of hydrogen isotopes for reasons of safety. Each coil was quickly immersed in a stirred bath of ethylene glycol at a temperature of approximately 100 degrees Celsius. The coil pressure increased, reflecting the increase in average temperature of its contents. The pressure transient was recored as a function of time after immersion. Because of the actual process will use Pd/k instead of kieselguhr, additional tests were run to determine the differences in thermal properties between the two materials. The method was to position a thermocouple at the center of a hollow sphere and pack the sphere with Pd/k. The sphere was sealed, quickly

  18. Single Event Transients in Linear Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Buchner, Stephen; McMorrow, Dale

    2005-01-01

    On November 5, 2001, a processor reset occurred on board the Microwave Anisotropy Probe (MAP), a NASA mission to measure the anisotropy of the microwave radiation left over from the Big Bang. The reset caused the spacecraft to enter a safehold mode from which it took several days to recover. Were that to happen regularly, the entire mission would be compromised, so it was important to find the cause of the reset and, if possible, to mitigate it. NASA assembled a team of engineers that included experts in radiation effects to tackle the problem. The first clue was the observation that the processor reset occurred during a solar event characterized by large increases in the proton and heavy ion fluxes emitted by the sun. To the radiation effects engineers on the team, this strongly suggested that particle radiation might be the culprit, particularly when it was discovered that the reset circuit contained three voltage comparators (LM139). Previous testing revealed that large voltage transients, or glitches appeared at the output of the LM139 when it was exposed to a beam of heavy ions [NI96]. The function of the reset circuit was to monitor the supply voltage and to issue a reset command to the processor should the voltage fall below a reference of 2.5 V [PO02]. Eventually, the team of engineers concluded that ionizing particle radiation from the solar event produced a negative voltage transient on the output of one of the LM139s sufficiently large to reset the processor on MAP. Fortunately, as of the end of 2004, only two such resets have occurred. The reset on MAP was not the first malfunction on a spacecraft attributed to a transient. That occurred shortly after the launch of NASA s TOPEX/Poseidon satellite in 1992. It was suspected, and later confirmed, that an anomaly in the Earth Sensor was caused by a transient in an operational amplifier (OP-15) [KO93]. Over the next few years, problems on TDRS, CASSINI, [PR02] SOHO [HA99,HA01] and TERRA were also attributed

  19. The Transient Radio Sky

    NASA Astrophysics Data System (ADS)

    Keane, E. F.

    2010-11-01

    The high time-resolution radio sky represents unexplored astronomical territory where the discovery potential is high. In this thesis I have studied the transient radio sky, focusing on millisecond scales. As such, this work is concerned primarily with neutron stars, the mostpopulous member of the radio transient parameter space. In particular, I have studied the well known radio pulsars and the recently identified group of neutron stars which show erratic radio emission, known as RRATs, which show radio bursts every few minutes to every few hours. When RRATs burst onto the scene in 2006, it was thought that they represented a previously unknown, distinct class of sporadically emitting sources. The difficulty in their identification implies a large underlying population, perhaps larger than the radio pulsars. The first question investigated in this thesis was whether the large projected population of RRATs posed a problem, i.e. could the observed supernova rate account for so many sources. In addition to pulsars and RRATs, the various other known neutron star manifestations were considered, leading to the conclusion that distinct populations would result in a `birthrate problem'. Evolution between the classes could solve this problem -- the RRATs are not a distinct population ofneutron stars.Alternatively, perhaps the large projected population of RRATs is an overestimate. To obtain an improved estimate, the best approach is to find more sources. The Parkes Multi-beam Pulsar Survey, wherein the RRATs were initially identified, offered an opportunity to do just this. Abouthalf of the RRATs showing bursts during the survey were thought to have been missed, due to the deleterious effects of impulsive terrestrial interference signals. To remove these unwanted signals, so that we could identify the previously shrouded RRATs, we developed newinterference mitigation software and processing techniques. Having done this, the survey was completely re-processed, resulting in

  20. Coupling analysis of transient cardiovascular dynamics.

    PubMed

    Müller, Andreas; Riedl, Maik; Penzel, Thomas; Bonnemeier, Hendrik; Kurths, Jürgen; Wessel, Niels

    2013-04-01

    The analysis of effects from coupling in and between systems is important in data-driven investigations as practiced in many scientific fields. It allows deeper insights into the mechanisms of interaction emerging among individual smaller systems when forming complex systems as in the human circulatory system. For systems featuring various regimes, usually only the epochs before and after a transition between different regimes are analyzed, although relevant information might be hidden within these transitions. Transient behavior of cardiovascular variables may emerge, on the one hand, from the recovery of the system after a severe disturbance or, on the other hand, from adaptive behavior throughout changes of states. It contains important information about the processes involved and the relations between state variables such as heart rate, blood pressure, and respiration. Therefore, we apply an ensemble approach to extend the method of symbolic coupling traces to time-variant coupling analysis. These new ensemble symbolic coupling traces are capable of determining coupling direction, strength, and time offset τ from transient dynamics in multivariate cardiovascular data. We use this method to analyze data recorded during an orthostatic test to reveal a transient structure that cannot be detected by classic methods.

  1. Experimental Investigation of Transient Sublimator Performance

    NASA Technical Reports Server (NTRS)

    Sheth, Rubik B.; Stephan, Ryan A.; Leimkuehler, Thomas O.

    2012-01-01

    Sublimators have been used as heat rejection devices for a variety of space applications including the Apollo Lunar Module and the Extravehicular Mobility Unit (EMU). Sublimators typically operate with steady-state feedwater utilization at or near 100%. However, sublimators are currently being considered for operations in a cyclical topping mode, which represents a new mode of operation for sublimators. Sublimators can be used as a supplemental heat rejection device during mission phases where the environmental temperature or heat rejection requirement changes rapidly. This scenario may occur during low lunar orbit, low earth orbit, or other planetary orbits. In these mission phases, the need for supplemental heat rejection will vary between zero and some fraction of the overall heat load. In particular, supplemental heat rejection is required for the portion of the orbit where the radiative sink temperature exceeds the system setpoint temperature. This paper will describe the effects of these transient starts and stops on the feedwater utilization during various feedwater timing scenarios. Experimental data from various scenarios is analyzed to investigate feedwater consumption efficiency under the cyclical conditions. Start up utilization tests were conducted to better understand the transient performance. This paper also provides recommendations for future sublimator design and transient operation.

  2. Photonic Nonlinear Transient Computing with Multiple-Delay Wavelength Dynamics

    NASA Astrophysics Data System (ADS)

    Martinenghi, Romain; Rybalko, Sergei; Jacquot, Maxime; Chembo, Yanne K.; Larger, Laurent

    2012-06-01

    We report on the experimental demonstration of a hybrid optoelectronic neuromorphic computer based on a complex nonlinear wavelength dynamics including multiple delayed feedbacks with randomly defined weights. This neuromorphic approach is based on a new paradigm of a brain-inspired computational unit, intrinsically differing from Turing machines. This recent paradigm consists in expanding the input information to be processed into a higher dimensional phase space, through the nonlinear transient response of a complex dynamics excited by the input information. The computed output is then extracted via a linear separation of the transient trajectory in the complex phase space. The hyperplane separation is derived from a learning phase consisting of the resolution of a regression problem. The processing capability originates from the nonlinear transient, resulting in nonlinear transient computing. The computational performance is successfully evaluated on a standard benchmark test, namely, a spoken digit recognition task.

  3. Radiation-Induced Transient Effects in Near Infrared Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Reed, Robert A.; Pickel, J.; Marshall, P.; Waczynski, A.; McMurray, R.; Gee, G.; Polidan, E.; Johnson, S.; McKeivey, M.; Ennico, K.; Johnson, R.

    2004-01-01

    This viewgraph presentation describes a test simulate the transient effects of cosmic ray impacts on near infrared focal plane arrays. The objectives of the test are to: 1) Characterize proton single events as function of energy and angle of incidence; 2) Measure charge spread (crosstalk) to adjacent pixels; 3) Assess transient recovery time.

  4. A transient overpower experiment in EBR-II

    SciTech Connect

    Herzog, J.P.; Tsai, H.; Dean, E.M.; Aoyama, T.; Yamamoto, K.

    1994-03-01

    The TOPI-IE test was a transient overpower test on irradiate mixed-oxide fuel pins in the Experimental Breeder Reactor-II (EBR-II). The test, the fifth in a series, was part of a cooperative program between the US Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan to conduct operational transient testing on mixed-oxide fuel pins in the metal-fueled EBR-II. The principle objective of the TOPI-1E test was to assess breaching margins for irradiated mixed-oxide fuel pins over the Plant Protection System (PPS) thresholds during a slow, extended overpower transient. This paper describes the effect of the TOPI-1E experiment on reactor components and the impact of the experiment on the long-term operability of the reactor. The paper discusses the role that SASSYS played in the pre-test safety analysis of the experiment. The ability of SASSYS to model transient overpower events is detailed by comparisons of data from the experiment with computed reactor variables from a SASSYS post-test simulation of the experiment.

  5. Transient Faults in Computer Systems

    NASA Technical Reports Server (NTRS)

    Masson, Gerald M.

    1993-01-01

    A powerful technique particularly appropriate for the detection of errors caused by transient faults in computer systems was developed. The technique can be implemented in either software or hardware; the research conducted thus far primarily considered software implementations. The error detection technique developed has the distinct advantage of having provably complete coverage of all errors caused by transient faults that affect the output produced by the execution of a program. In other words, the technique does not have to be tuned to a particular error model to enhance error coverage. Also, the correctness of the technique can be formally verified. The technique uses time and software redundancy. The foundation for an effective, low-overhead, software-based certification trail approach to real-time error detection resulting from transient fault phenomena was developed.

  6. Transient voltage oscillations in coils

    SciTech Connect

    Chowdhuri, P.

    1985-01-01

    Magnet coils may be excited into internal voltage oscillations by transient voltages. Such oscillations may electrically stress the magnet's dielectric components to many times its normal stress. This may precipitate a dielectric failure, and the attendant prolonged loss of service and costly repair work. Therefore, it is important to know the natural frequencies of oscillations of a magnet during the design stage, and to determine whether the expected switching transient voltages can excite the magnet into high-voltage internal oscillations. The series capacitance of a winding significantly affects its natural frequencies. However, the series capacitance is difficult to calculate, because it may comprise complex capacitance network, consisting of intra- and inter-coil turn-to-turn capacitances of the coil sections. A method of calculating the series capacitance of a winding is proposed. This method is rigorous but simple to execute. The time-varying transient voltages along the winding are also calculated.

  7. Cohabitation Duration and Transient Domesticity.

    PubMed

    Golub, Andrew; Reid, Megan; Strickler, Jennifer; Dunlap, Eloise

    2013-01-01

    Research finds that many impoverished urban Black adults engage in a pattern of partnering and family formation involving a succession of short cohabitations yielding children, a paradigm referred to as transient domesticity. Researchers have identified socioeconomic status, cultural adaptations, and urbanicity as explanations for aspects of this pattern. We used longitudinal data from the 2001 Survey of Income and Program Participation to analyze variation in cohabitation and marriage duration by race/ethnicity, income, and urban residence. Proportional hazards regression indicated that separation risk is greater among couples that are cohabiting, below 200% of the federal poverty line, and Black but is not greater among urban dwellers. This provides empirical demographic evidence to support the emerging theory of transient domesticity and suggests that both socioeconomic status and race explain this pattern. We discuss the implications of these findings for understanding transient domesticity and make recommendations for using the Survey of Income and Program Participation to further study this family formation paradigm.

  8. Program for the Analysis of Reactor Transients

    2002-01-29

    This program is designed for use in predicting the course of and consequence of nondestructive accidents in research and test reactor cores. It is intended primarily for the analysis of plate type research and test reactors and has been subjected to extensive comparisons with the SPERT I and SPERT II experiments. These comparisons were quite favorable for a wide range of transients up to and including melting of the clad. Favorable comparisons have also beenmore » made for TRIGA reactor pulses in pin geometry. The PARET/ANL code has been used by the RERTR (Reduced Enrichment Research and Test Reactor) Program for the safety evaluation of many of the candidate reactors for reduced enrichment.« less

  9. Studies of Transient Meteor Activity

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter M. M.

    2002-01-01

    Meteoroids bombard Earth's atmosphere daily, but occasionally meteor rates increase to unusual high levels when Earth crosses the relatively fresh ejecta of comets. These transient events in meteor activity provide clues about the whereabouts of Earth-threatening long-period comets, the mechanisms of large-grain dust ejection from comets, and the particle composition and size distribution of the cometary ejecta. Observations of these transient events provide important insight in natural processes that determine the large grain dust environment of comets, in natural phenomena that were prevalent during the time of the origin of life, and in processes that determine the hazard of civilizations to large impacts and of man-made satellites to the periodic blizzard of small meteoroids. In this proposal, three tasks form a coherent program aimed at elucidating various aspects of meteor outbursts, with special reference to planetary astronomy and astrobiology. Task 1 was a ground-based effort to observe periods of transient meteor activity. This includes: (1) stereoscopic imaging of meteors during transient meteor events for measurements of particle size distribution, meteoroid orbital dispersions and fluxes; and (2) technical support for Global-MS-Net, a network of amateur-operated automatic counting stations for meteor reflections from commercial VHF radio and TV broadcasting stations, keeping a 24h vigil on the level of meteor activity for the detection of new meteor streams. Task 2 consisted of ground-based and satellite born spectroscopic observations of meteors and meteor trains during transient meteor events for measurements of elemental composition, the presence of organic matter in the meteoroids, and products generated by the interaction of the meteoroid with the atmosphere. Task 3 was an airborne effort to explore the 2000 Leonid meteor outbursts, which are anticipated to be the most significant of transient meteor activity events in the remainder of the

  10. Transient classification and novae ejecta

    NASA Astrophysics Data System (ADS)

    Williams, Robert

    2016-07-01

    A third parameter, in addition to luminosity and rate of brightness decline, derived from the spectra of transients is suggested as a means of more accurately classifying objects in outburst. Principal component analysis of the spectra of transients is suggested as the best way to determine the third parameter. A model is suggested for novae ejecta that is based on the ballistic ejection of an ensemble of clouds having a wide range of sizes. Short term brightness fluctuations of novae, the formation of dust, and the production of X-ray emission follow naturally from such a picture of the evolving clouds.

  11. Modeling a Transient Catalytic Combustor

    NASA Technical Reports Server (NTRS)

    Tien, J. S.

    1985-01-01

    Transient model of monolith catalytic combustor presented in report done under NASA/DOE contract. Model assumes quasi-steady gas phase and thermally "thin" solid. In gas-phase treatment, several quasi-global chemical reactions assumed capable of describing CO and unburnt hydrocarbon emissions in fuel-lean operations. In steady-state computation presented, influence of selected operating and design parameters on minimum combustor length studied. When fast transient responses required, both steady and unsteady studies made to achieve meaningful compromise in design.

  12. Lifetime Reliability Prediction of Ceramic Structures Under Transient Thermomechanical Loads

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Jadaan, Osama J.; Gyekenyesi, John P.

    2005-01-01

    An analytical methodology is developed to predict the probability of survival (reliability) of ceramic components subjected to harsh thermomechanical loads that can vary with time (transient reliability analysis). This capability enables more accurate prediction of ceramic component integrity against fracture in situations such as turbine startup and shutdown, operational vibrations, atmospheric reentry, or other rapid heating or cooling situations (thermal shock). The transient reliability analysis methodology developed herein incorporates the following features: fast-fracture transient analysis (reliability analysis without slow crack growth, SCG); transient analysis with SCG (reliability analysis with time-dependent damage due to SCG); a computationally efficient algorithm to compute the reliability for components subjected to repeated transient loading (block loading); cyclic fatigue modeling using a combined SCG and Walker fatigue law; proof testing for transient loads; and Weibull and fatigue parameters that are allowed to vary with temperature or time. Component-to-component variation in strength (stochastic strength response) is accounted for with the Weibull distribution, and either the principle of independent action or the Batdorf theory is used to predict the effect of multiaxial stresses on reliability. The reliability analysis can be performed either as a function of the component surface (for surface-distributed flaws) or component volume (for volume-distributed flaws). The transient reliability analysis capability has been added to the NASA CARES/ Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. CARES/Life was also updated to interface with commercially available finite element analysis software, such as ANSYS, when used to model the effects of transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

  13. Detection of Fast Transients with Radio Interferometric Arrays

    NASA Astrophysics Data System (ADS)

    Bhat, N. D. R.; Chengalur, J. N.; Cox, P. J.; Gupta, Y.; Prasad, J.; Roy, J.; Bailes, M.; Burke-Spolaor, S.; Kudale, S. S.; van Straten, W.

    2013-05-01

    Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg2 of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  14. DETECTION OF FAST TRANSIENTS WITH RADIO INTERFEROMETRIC ARRAYS

    SciTech Connect

    Bhat, N. D. R.; Chengalur, J. N.; Gupta, Y.; Prasad, J.; Roy, J.; Kudale, S. S.; Cox, P. J.; Bailes, M.; Burke-Spolaor, S.; Van Straten, W.

    2013-05-01

    Next-generation radio arrays, including the Square Kilometre Array (SKA) and its pathfinders, will open up new avenues for exciting transient science at radio wavelengths. Their innovative designs, comprising a large number of small elements, pose several challenges in digital processing and optimal observing strategies. The Giant Metre-wave Radio Telescope (GMRT) presents an excellent test-bed for developing and validating suitable observing modes and strategies for transient experiments with future arrays. Here we describe the first phase of the ongoing development of a transient detection system for GMRT that is planned to eventually function in a commensal mode with other observing programs. It capitalizes on the GMRT's interferometric and sub-array capabilities, and the versatility of a new software backend. We outline considerations in the plan and design of transient exploration programs with interferometric arrays, and describe a pilot survey that was undertaken to aid in the development of algorithms and associated analysis software. This survey was conducted at 325 and 610 MHz, and covered 360 deg{sup 2} of the sky with short dwell times. It provides large volumes of real data that can be used to test the efficacies of various algorithms and observing strategies applicable for transient detection. We present examples that illustrate the methodologies of detecting short-duration transients, including the use of sub-arrays for higher resilience to spurious events of terrestrial origin, localization of candidate events via imaging, and the use of a phased array for improved signal detection and confirmation. In addition to demonstrating applications of interferometric arrays for fast transient exploration, our efforts mark important steps in the roadmap toward SKA-era science.

  15. Sustained Perceptual Deficits from Transient Sensory Deprivation

    PubMed Central

    Sanes, Dan H.

    2015-01-01

    Sensory pathways display heightened plasticity during development, yet the perceptual consequences of early experience are generally assessed in adulthood. This approach does not allow one to identify transient perceptual changes that may be linked to the central plasticity observed in juvenile animals. Here, we determined whether a brief period of bilateral auditory deprivation affects sound perception in developing and adult gerbils. Animals were reared with bilateral earplugs, either from postnatal day 11 (P11) to postnatal day 23 (P23) (a manipulation previously found to disrupt gerbil cortical properties), or from P23-P35. Fifteen days after earplug removal and restoration of normal thresholds, animals were tested on their ability to detect the presence of amplitude modulation (AM), a temporal cue that supports vocal communication. Animals reared with earplugs from P11-P23 displayed elevated AM detection thresholds, compared with age-matched controls. In contrast, an identical period of earplug rearing at a later age (P23-P35) did not impair auditory perception. Although the AM thresholds of earplug-reared juveniles improved during a week of repeated testing, a subset of juveniles continued to display a perceptual deficit. Furthermore, although the perceptual deficits induced by transient earplug rearing had resolved for most animals by adulthood, a subset of adults displayed impaired performance. Control experiments indicated that earplugging did not disrupt the integrity of the auditory periphery. Together, our results suggest that P11-P23 encompasses a critical period during which sensory deprivation disrupts central mechanisms that support auditory perceptual skills. SIGNIFICANCE STATEMENT Sensory systems are particularly malleable during development. This heightened degree of plasticity is beneficial because it enables the acquisition of complex skills, such as music or language. However, this plasticity comes with a cost: nervous system development

  16. Verification and validation of COBRA-SFS transient analysis capability

    SciTech Connect

    Rector, D.R.; Michener, T.E.; Cuta, J.M.

    1998-05-01

    This report provides documentation of the verification and validation testing of the transient capability in the COBRA-SFS code, and is organized into three main sections. The primary documentation of the code was published in September 1995, with the release of COBRA-SFS, Cycle 2. The validation and verification supporting the release and licensing of COBRA-SFS was based solely on steady-state applications, even though the appropriate transient terms have been included in the conservation equations from the first cycle. Section 2.0, COBRA-SFS Code Description, presents a capsule description of the code, and a summary of the conservation equations solved to obtain the flow and temperature fields within a cask or assembly model. This section repeats in abbreviated form the code description presented in the primary documentation (Michener et al. 1995), and is meant to serve as a quick reference, rather than independent documentation of all code features and capabilities. Section 3.0, Transient Capability Verification, presents a set of comparisons between code calculations and analytical solutions for selected heat transfer and fluid flow problems. Section 4.0, Transient Capability Validation, presents comparisons between code calculations and experimental data obtained in spent fuel storage cask tests. Based on the comparisons presented in Sections 2.0 and 3.0, conclusions and recommendations for application of COBRA-SFS to transient analysis are presented in Section 5.0.

  17. Large liquid rocket engine transient performance simulation system

    NASA Technical Reports Server (NTRS)

    Mason, J. R.; Southwick, R. D.

    1991-01-01

    A simulation system, ROCETS, was designed and developed to allow cost-effective computer predictions of liquid rocket engine transient performance. The system allows a user to generate a simulation of any rocket engine configuration using component modules stored in a library through high-level input commands. The system library currently contains 24 component modules, 57 sub-modules and maps, and 33 system routines and utilities. FORTRAN models from other sources can be operated in the system upon inclusion of interface information on comment cards. Operation of the simulation is simplified for the user by run, execution, and output processors. The simulation system makes available steady-state trim balance, transient operation, and linear partial generation. The system utilizes a modern equation solver for efficient operation of the simulations. Transient integration methods include integral and differential forms for the trapezoidal, first order Gear, and second order Gear corrector equations. A detailed technology test bed engine (TTBE) model was generated to be used as the acceptance test of the simulation system. The general level of model detail was that reflected in the Space Shuttle Main Engine DTM. The model successfully obtained steady-state balance in main stage operation and simulated throttle transients, including engine starts and shutdown. A NASA FORTRAN control model was obtained, ROCETS interface installed in comment cards, and operated with the TTBE model in closed-loop transient mode.

  18. Simulated transient behavior of HT9 cladding

    SciTech Connect

    Cannon, N.S.; Huang, F.H.; Hamilton, M.L.

    1988-09-01

    Simulated transient tests were performed on sections of HT9 fast- reactor fuel pin cladding irradiated to a fast fluence of nearly 16 /times/ 10/sup 22/ n/cm/sup 2/ at temperatures ranging from 370 to 620/degree/C. After removing fuel, these specimens were internally pressurized and heated at one of several constant rates (0.56, 5.6, or 110/degree/C/s) until specimen failure occurred. A slight reduction of strength was observed in irradiated cladding, particularly at 110/degree/C/s, when compared with transient results from unirradiated HT9 control specimens; however, this strength reduction did not correlate with either fluence or irradiation temperature. A small reduction of ductility was also observed for irradiated cladding failing at temperatures above 800/degree/C at the lower heating rates (0.56 or 5.6/degree/C/s); irradiated cladding was generally more ductile at 110/degree/C/s than unirradiated HT9 cladding. The HT9 cladding results were compared with similar transient data obtained previously from 20% Cold-Worked Type 316 Stainless Steel (316 SS) cladding. In the unirradiated state, this austenitic cladding is stronger and less ductile than HT9 cladding. However, the 316 SS cladding undergoes a significant loss of strength and ductility during irradiation when in contact with oxide fuel, by a mechanism labeled the fuel adjacency effect (FAE). The FAE is believed to be liquid metal embrittlement from fission products. The HT9 fuel pin cladding remained as strong or stronger than the 316 SS cladding when irradiated in contact with fuel, showing no evidence of the FAE up to the high fluences reported here. The ductility of the irradiated HT9 fuel pin cladding remained significantly greater than that of irradiated 316 SS cladding. 14 refs., 11 figs., 1 tab.

  19. Transient analysis of a capillary pumped loop heat pipe

    NASA Technical Reports Server (NTRS)

    Kiper, A. M.; Feric, G.; Anjum, M. I.; Swanson, T. D.

    1990-01-01

    A bench-top Capillary Pumped Loop (CPL) test system has been developed and tested to investigate the transient mode operation of this system by applying a step power input to the evaporators. Tests were conducted at several power input and evaporator inlet subcooling combinations. In addition, a lumped-heat-capacity model of the CPL test system has been presented which is used for predicting qualitatively the transient operation characteristics. Good agreement has been obtained between the predicted and the measured temperature variations. A simple evaporator inlet subcooler model has also been developed to study effects of inlet subcooling on the steady-state evaporator wall temperature. Results were compared with the test data collected.

  20. Impaired picture recognition in transient epileptic amnesia.

    PubMed

    Dewar, Michaela; Hoefeijzers, Serge; Zeman, Adam; Butler, Christopher; Della Sala, Sergio

    2015-01-01

    Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Transient epileptic amnesia is often associated with the rapid decline in recall of new information over hours to days (accelerated long-term forgetting - 'ALF'). It remains unknown how recognition memory is affected in TEA over time. Here, we report a systematic study of picture recognition in patients with TEA over the course of one week. Sixteen patients with TEA and 16 matched controls were presented with 300 photos of everyday life scenes. Yes/no picture recognition was tested 5min, 2.5h, 7.5h, 24h, and 1week after picture presentation using a subset of target pictures as well as similar and different foils. Picture recognition was impaired in the patient group at all test times, including the 5-minute test, but it declined normally over the course of 1week. This impairment was associated predominantly with an increased false alarm rate, especially for similar foils. High performance on a control test indicates that this impairment was not associated with perceptual or discrimination deficits. Our findings suggest that, at least in some TEA patients with ALF in verbal recall, picture recognition does not decline more rapidly than in controls over 1week. However, our findings of an early picture recognition deficit suggest that new visual memories are impoverished after minutes in TEA. This could be the result of deficient encoding or impaired early consolidation. The early picture recognition deficit observed could reflect either the early stages of the process that leads to ALF or a separable deficit of anterograde memory in TEA. Lastly, our study suggests that at least some patients with TEA are prone to falsely recognizing new everyday visual information that they have not in fact seen previously. This deficit, alongside their ALF in free recall, likely affects everyday memory performance.

  1. Impaired picture recognition in transient epileptic amnesia.

    PubMed

    Dewar, Michaela; Hoefeijzers, Serge; Zeman, Adam; Butler, Christopher; Della Sala, Sergio

    2015-01-01

    Transient epileptic amnesia (TEA) is an epileptic syndrome characterized by recurrent, brief episodes of amnesia. Transient epileptic amnesia is often associated with the rapid decline in recall of new information over hours to days (accelerated long-term forgetting - 'ALF'). It remains unknown how recognition memory is affected in TEA over time. Here, we report a systematic study of picture recognition in patients with TEA over the course of one week. Sixteen patients with TEA and 16 matched controls were presented with 300 photos of everyday life scenes. Yes/no picture recognition was tested 5min, 2.5h, 7.5h, 24h, and 1week after picture presentation using a subset of target pictures as well as similar and different foils. Picture recognition was impaired in the patient group at all test times, including the 5-minute test, but it declined normally over the course of 1week. This impairment was associated predominantly with an increased false alarm rate, especially for similar foils. High performance on a control test indicates that this impairment was not associated with perceptual or discrimination deficits. Our findings suggest that, at least in some TEA patients with ALF in verbal recall, picture recognition does not decline more rapidly than in controls over 1week. However, our findings of an early picture recognition deficit suggest that new visual memories are impoverished after minutes in TEA. This could be the result of deficient encoding or impaired early consolidation. The early picture recognition deficit observed could reflect either the early stages of the process that leads to ALF or a separable deficit of anterograde memory in TEA. Lastly, our study suggests that at least some patients with TEA are prone to falsely recognizing new everyday visual information that they have not in fact seen previously. This deficit, alongside their ALF in free recall, likely affects everyday memory performance. PMID:25506793

  2. Exploring the Optical Transient Sky with the Palomar Transient Factory

    NASA Astrophysics Data System (ADS)

    Rau, Arne; Kulkarni, Shrinivas R.; Law, Nicholas M.; Bloom, Joshua S.; Ciardi, David; Djorgovski, George S.; Fox, Derek B.; Gal-Yam, Avishay; Grillmair, Carl C.; Kasliwal, Mansi M.; Nugent, Peter E.; Ofek, Eran O.; Quimby, Robert M.; Reach, William T.; Shara, Michael; Bildsten, Lars; Cenko, S. Bradley; Drake, Andrew J.; Filippenko, Alexei V.; Helfand, David J.; Helou, George; Howell, D. Andrew; Poznanski, Dovi; Sullivan, Mark

    2009-12-01

    The Palomar Transient Factory (PTF) is a wide-field experiment designed to investigate the optical transient and variable sky on time scales from minutes to years. PTF uses the CFH12k mosaic camera, with a field of view of 7.9 deg2 and a plate scale of 1'' pixel-1, mounted on the Palomar Observatory 48 inch Samuel Oschin Telescope. The PTF operation strategy is devised to probe the existing gaps in the transient phase space and to search for theoretically predicted, but not yet detected, phenomena, such as fallback supernovae, macronovae, .Ia supernovae, and the orphan afterglows of gamma-ray bursts. PTF will also discover many new members of known source classes, from cataclysmic variables in their various avatars to supernovae and active galactic nuclei, and will provide important insights into understanding galactic dynamics (through RR Lyrae stars) and the solar system (asteroids and near-Earth objects). The lessons that can be learned from PTF will be essential for the preparation of future large synoptic sky surveys like the Large Synoptic Survey Telescope. In this article we present the scientific motivation for PTF and describe in detail the goals and expectations for this experiment.

  3. A throat-bypass stability-bleed system using relief valves to increase the transient stability of a mixed-compression inlet. [YF-12 aircraft inlet tests in the Lewis 10 by 10 ft supersonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Neiner, G. H.; Dustin, M. O.; Cole, G. L.

    1979-01-01

    A stability-bleed system was installed in a YF-12 flight inlet that was subjected to internal and external airflow disturbances in the NASA Lewis 10 by 10 foot supersonic wind tunnel. The purpose of the system is to allow higher inlet performance while maintaining a substantial tolerance (without unstart) to internal and external disturbances. At Mach numbers of 2.47 and 2.76, the inlet tolerance to decreases in diffuser-exit corrected airflow was increased by approximately 10 percent of the operating-point airflow. The stability-bleed system complemented the terminal-shock-control system of the inlet and did not show interaction problems. For disturbances which caused a combined decrease in Mach number and increase in angle of attack, the system with valves operative kept the inlet started 4 to 28 times longer than with the valves inoperative. Hence, the stability system provides additional time for the inlet control system to react and prevent unstart. This was observed for initial Mach numbers of 2.55 and 2.68. For slow increase in angle of attack at Mach 2.47 and 2.76, the system kept the inlet started beyond the steady-state unstart angle. However, the maximum transient angles of attack without unstart could not be determined because wind-tunnel mechanical-stop limits for angle of attack were reached.

  4. Spectroscopic Classifications of Optical Transients with SOAR

    NASA Astrophysics Data System (ADS)

    Hounsell, R. A.; Miller, J. A.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2016-06-01

    We report the following classifications of optical transients from spectroscopic observations with the Goodman spectrograph on the SOAR 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST).

  5. TINY HICCUPS TO TITANIC EXPLOSIONS: Tackling Transients in Anomalous X-ray Pulsars

    NASA Astrophysics Data System (ADS)

    Kaspi, Victoria

    2007-09-01

    Recently discovered transient events in Anomalous X-ray Pulsars (AXPs) may be a Rosetta Stone for understanding the persistent emission from magnetars. They also may hold the key to quantifying the number of magnetars in the Galaxy. Here we request Chandra TOO time to observe any AXP following a rare transient event, including a major outburst or a long-duration flare. Specifically, the requested observations will determine the pulsed fraction and spectral evolution of a transient AXP event as the source relaxes back to quiescence, in order to quantitatively test the "twisted magnetosphere" model for magnetars, and establish the basic phenomenology of transient AXP events.

  6. Tiny Hiccups To Titanic Explosions: Tackling Transients in Anomalous X-ray Pulsars

    NASA Astrophysics Data System (ADS)

    Kaspi, Victoria

    2006-09-01

    Recently discovered transient events in Anomalous X-ray Pulsars (AXPs) may be a Rosetta Stone for understanding the persistent emission from magnetars. They also may hold the key to quantifying the number of magnetars in the Galaxy. Here we request Chandra TOO time to observe any AXP following a rare transient event, including a major outburst or a long-duration flare. Specifically, the requested observations will determine the pulsed fraction and spectral evolution of a transient AXP event as the source relaxes back to quiescence, in order to quantitatively test the "twisted magnetosphere" model for magnetars, and establish the basic phenomenology of transient AXP events.

  7. TINY HICCUPS TO TITANIC EXPLOSIONS: Tackling Transients in Anomalous X-ray Pulsars

    NASA Astrophysics Data System (ADS)

    Kaspi, Victoria

    2005-09-01

    Recently discovered transient events in Anomalous X-ray Pulsars (AXPs) may be a Rosetta Stone for understanding the persistent emission from magnetars. They also may hold the key to quantifying the number of magnetars in the Galaxy. Here we request Chandra TOO time to observe any AXP following a rare transient event, including a major outburst or a long-duration flare. Specifically, the requested observations will determine the pulsed fraction and spectral evolution of a transient AXP event as the source relaxes back to quiescence, in order to quantitatively test the "twisted magnetosphere" model for magnetars, and establish the basic phenomenology of transient AXP events.

  8. Transient Relay Function of Midline Thalamic Nuclei during Long-Term Memory Consolidation in Humans

    ERIC Educational Resources Information Center

    Thielen, Jan-Willem; Takashima, Atsuko; Rutters, Femke; Tendolkar, Indira; Fernández, Guillén

    2015-01-01

    To test the hypothesis that thalamic midline nuclei play a transient role in memory consolidation, we reanalyzed a prospective functional MRI study, contrasting recent and progressively more remote memory retrieval. We revealed a transient thalamic connectivity increase with the hippocampus, the medial prefrontal cortex (mPFC), and a…

  9. Superresolution microscopy with transient binding.

    PubMed

    Molle, Julia; Raab, Mario; Holzmeister, Susanne; Schmitt-Monreal, Daniel; Grohmann, Dina; He, Zhike; Tinnefeld, Philip

    2016-06-01

    For single-molecule localization based superresolution, the concentration of fluorescent labels has to be thinned out. This is commonly achieved by photophysically or photochemically deactivating subsets of molecules. Alternatively, apparent switching of molecules can be achieved by transient binding of fluorescent labels. Here, a diffusing dye yields bright fluorescent spots when binding to the structure of interest. As the binding interaction is weak, the labeling is reversible and the dye ligand construct diffuses back into solution. This approach of achieving superresolution by transient binding (STB) is reviewed in this manuscript. Different realizations of STB are discussed and compared to other localization-based superresolution modalities. We propose the development of labeling strategies that will make STB a highly versatile tool for superresolution microscopy at highest resolution. PMID:26773299

  10. Superresolution microscopy with transient binding.

    PubMed

    Molle, Julia; Raab, Mario; Holzmeister, Susanne; Schmitt-Monreal, Daniel; Grohmann, Dina; He, Zhike; Tinnefeld, Philip

    2016-06-01

    For single-molecule localization based superresolution, the concentration of fluorescent labels has to be thinned out. This is commonly achieved by photophysically or photochemically deactivating subsets of molecules. Alternatively, apparent switching of molecules can be achieved by transient binding of fluorescent labels. Here, a diffusing dye yields bright fluorescent spots when binding to the structure of interest. As the binding interaction is weak, the labeling is reversible and the dye ligand construct diffuses back into solution. This approach of achieving superresolution by transient binding (STB) is reviewed in this manuscript. Different realizations of STB are discussed and compared to other localization-based superresolution modalities. We propose the development of labeling strategies that will make STB a highly versatile tool for superresolution microscopy at highest resolution.

  11. Transient Ablation of Teflon Hemispheres

    NASA Technical Reports Server (NTRS)

    Arai, Norio; Karashima, Kei-ichi; Sato, Kiyoshi

    1997-01-01

    For high-speed entry of space vehicles into atmospheric environments, ablation is a practical method for alleviating severe aerodynamic heating. Several studies have been undertaken on steady or quasi-steady ablation. However, ablation is a very complicated phenomenon in which a nonequilibrium chemical process is associated with an aerodynamic process that involves changes in body shape with time. Therefore, it seems realistic to consider that ablation is an unsteady phenomenon. In the design of an ablative heat-shield system, since the ultimate purpose of the heat shield is to keep the internal temperature of the space vehicle at a safe level during entry, the transient heat conduction characteristics of the ablator may be critical in the selection of the material and its thickness. This note presents an experimental study of transient ablation of Teflon, with particular emphasis on the change in body shape, the instantaneous internal temperature distribution, and the effect of thermal expansion on ablation rate.

  12. Pressure transient in liquid lines

    SciTech Connect

    Sun, J.G.; Wang, X.Q.

    1995-07-01

    The pressure surge that results from a step change of flow in liquid pipelines, commonly known as water hammer, was analyzed by an eigenfunction method. A differential-integral Pressure wave equation and a linearized velocity equation were derived from the equations of mass and momentum conservation. Waveform distortion due to viscous dissipation and pipe-wall elastic expansion is characterized by a dimensionless transmission number K. The pressure surge condition, which is mathematically singular, was used in the solution procedure. The exact solutions from numerical calculation of the differential-integral equation provide a complete Pressure transient in the pipe. The problems are also calculated With the general-purpose computer code COMMIX, which solves the exact mass conservation equation and Navier-Stokes equations. These solutions were compared with published experimental results, and agreement was good. The effect of turbulence on the pressure transient is discussed in the light of COMMIX calculational results.

  13. Transient simulation of absorption machines

    NASA Astrophysics Data System (ADS)

    Anand, D. K.; Allen, R. W.; Kumar, B.

    A model for a water-cooled Lithium-Bromide/water absorption chiller is presented. Its transient response both during the start-up phase and during the shut-off period is predicted. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steady-state value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation.

  14. Nonlinear Diffusion and Transient Osmosis

    NASA Astrophysics Data System (ADS)

    Akira, Igarashi; Lamberto, Rondoni; Antonio, Botrugno; Marco, Pizzi

    2011-08-01

    We investigate both analytically and numerically the concentration dynamics of a solution in two containers connected by a narrow and short channel, in which diffusion obeys a porous medium equation. We also consider the variation of the pressure in the containers due to the flow of matter in the channel. In particular, we identify a phenomenon, which depends on the transport of matter across nano-porous membranes, which we call “transient osmosis". We find that nonlinear diffusion of the porous medium equation type allows numerous different osmotic-like phenomena, which are not present in the case of ordinary Fickian diffusion. Experimental results suggest one possible candidate for transiently osmotic processes.

  15. EPROM erasure in transient and total dose gamma environments

    NASA Astrophysics Data System (ADS)

    Linderman, P. B.; Okuma, J.

    1982-12-01

    Four versions of 32Kbit EPROMs from three manufacturers were exposed to transient gamma and total dose radiation environments. At a maximum tested transient level of 3.9 x 10 to the 9th rad(Si)/sec, the devices were found to be resistant to erasure. Failures from the total dose exposures occurred at different levels for the four device types. The most susceptible part type failed between 3200 and 4500 rad(Si). The most resistant type failed between 9500 and 11000 rad(Si). These variations in total dose failure threshold are attributed to the floating gate oxide thickness differences between the four versions of this EPROM.

  16. EPROM erasure in transient and total dose gamma environments

    SciTech Connect

    Linderman, P.B.; Kuma, J.O.

    1982-12-01

    Four versions of 32K bit EPROMs from three manufacturers were exposed to transient gamma and total dose radiation environments. At a maximum tested transient level of 3.9X10/sup 9/ rad (Si)/sec, the devices were found to be resistant to erasure. Failures from the total dose exposures occurred at different levels for the four device types. The most susceptible part type failed between 3200 and 4500 rad(Si). The most resistant type failed between 9500 and 11000 rad(Si). These variations in total dose failure threshold are attributed to the floating gate oxide thickness differences between the four versions of this EPROM.

  17. Transient stability assessment by pattern recognition in the frequency domain

    SciTech Connect

    Ostojic, D.R. ); Heydt, G.T. . School of Electrical Engineering)

    1991-02-01

    This paper presents pattern recognition methodology which utilizes spectral monitoring of electromechanical oscillations to assess the transient stability of interconnected power systems. The proposed frequency domain approach permits definitive recognition of unstable dynamic modes. This is used to design an adaptive linear classifier which, in the developmental implementation virtually eliminates both false dismissals, and false alarms. The result is an accurate and reliable decision-making system which performs transient stability monitoring and assessment in real-time. Production computer code has not yet been implemented, but it is expected that the cited performance in developmental tests will be duplicated.

  18. Vertical axis wind turbine drive train transient dynamics

    NASA Technical Reports Server (NTRS)

    Clauss, D. B.; Carne, T. G.

    1982-01-01

    Start up of a vertical axis wind turbine causes transient torque oscillations in the drive train with peak torques which may be over two and one half times the rated torque of the turbine. A computer code, based on a lumped parameter model of the drive train, was developed and tested for the low cost 17 meter turbine; the results show excellent agreement with field data. The code was used to predict the effect of a slip clutch on transient torque oscillations. It was demonstrated that a slip clutch located between the motor and brake can reduce peak torques by thirty eight percent.

  19. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-09-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  20. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-06-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  1. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-08-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  2. Nonlinear transient simulation of transformers

    SciTech Connect

    Pierrat, L.; Tran-Quoc, T. |; Montmeat, A.

    1995-12-31

    In this paper, a nonlinear model of transformer which takes into account both the saturation and the hysteresis is proposed. In order to simulate transient phenomena in transformers, a system of equations is presented. The digital simulation of the energization and de-energization of a three-phase distribution transformer is studied. Ferroresonant phenomena in iron core transformers supplied through capacitive links are presented. Finally, the influence of MOV arresters on overvoltage reduction is investigated.

  3. ATLAS discoveries of optical transients

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-10-01

    We report the following transients found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  4. TREAT Transient Analysis Benchmarking for the HEU Core

    SciTech Connect

    Kontogeorgakos, D. C.; Connaway, H. M.; Wright, A. E.

    2014-05-01

    This work was performed to support the feasibility study on the potential conversion of the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory from the use of high enriched uranium (HEU) fuel to the use of low enriched uranium (LEU) fuel. The analyses were performed by the GTRI Reactor Conversion staff at the Argonne National Laboratory (ANL). The objective of this study was to benchmark the transient calculations against temperature-limited transients performed in the final operating HEU TREAT core configuration. The MCNP code was used to evaluate steady-state neutronics behavior, and the point kinetics code TREKIN was used to determine core power and energy during transients. The first part of the benchmarking process was to calculate with MCNP all the neutronic parameters required by TREKIN to simulate the transients: the transient rod-bank worth, the prompt neutron generation lifetime, the temperature reactivity feedback as a function of total core energy, and the core-average temperature and peak temperature as a functions of total core energy. The results of these calculations were compared against measurements or against reported values as documented in the available TREAT reports. The heating of the fuel was simulated as an adiabatic process. The reported values were extracted from ANL reports, intra-laboratory memos and experiment logsheets and in some cases it was not clear if the values were based on measurements, on calculations or a combination of both. Therefore, it was decided to use the term “reported” values when referring to such data. The methods and results from the HEU core transient analyses will be used for the potential LEU core configurations to predict the converted (LEU) core’s performance.

  5. Possible Nearby Transient discovered by PSST

    NASA Astrophysics Data System (ADS)

    Wright, D.; Smith, K. W.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-01-01

    A transient, which is a possible nearby supernova, has been discovered as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  6. Transient ponderomotive effects in superconducting cavities

    SciTech Connect

    Kirk Davis; Thomas Powers

    2005-07-10

    A number of experiments were performed on an installed and operational 5-cell CEBAF cavity to determine the minimum time required to re-establish stable gradient after a cavity window arc trip. Once it was determined that gradient could be re-established within 10 ms by applying constant power RF signal in a voltage controlled Oscillator-phase locked loop based system (VCO-PLL), a second experiment was performed to determine if stable gradient could be re-established using a fixed frequency RF system with a simple gradient based closed loop control system. During this test, fluctuations were observed in the cavity forward power signal, the source of which was later determined to be pondero-motive in nature. These ponderomotive induced vibrations were quantified using a cavity resonance monitor and a VCO-PLL RF system. Experimental results, analysis of the resultant klystron power transients, the decay time of the transients, and the implications with respect to fast reset algorithms will be presented.

  7. Nonlinear transient analysis of joint dominated structures

    NASA Technical Reports Server (NTRS)

    Chapman, J. M.; Shaw, F. H.; Russell, W. C.

    1987-01-01

    A residual force technique is presented that can perform the transient analyses of large, flexible, and joint dominated structures. The technique permits substantial size reduction in the number of degrees of freedom describing the nonlinear structural models and can account for such nonlinear joint phenomena as free-play and hysteresis. In general, joints can have arbitrary force-state map representations but these are used in the form of residual force maps. One essential feature of the technique is to replace the arbitrary force-state maps describing the nonlinear joints with residual force maps describing the truss links. The main advantage of this replacement is that the incrementally small relative displacements and velocities across a joint are not monitored directly thereby avoiding numerical difficulties. Instead, very small and 'soft' residual forces are defined giving a numerically attractive form for the equations of motion and thereby permitting numerically stable integration algorithms. The technique was successfully applied to the transient analyses of a large 58 bay, 60 meter truss having nonlinear joints. A method to perform link testing is also presented.

  8. Transient-mode multipactor discharge

    NASA Astrophysics Data System (ADS)

    Graves, T. P.; Spektor, R.; Stout, P.; Axley, A.

    2009-08-01

    Multipactor discharge is a resonant condition in which electrons impact material surfaces in phase with an alternating rf or microwave electric field. A growing and/or sustained discharge requires the electrode secondary electron coefficient, δ(Ee), to be greater than unity at the impacting electron energy (Ee). E1, the minimum energy for δ =1, is highly dependent on electrode surface preparation and conditioning, and contaminated surfaces will generally experience a lower E1 than the same clean or "conditioned" surface. A transient mode of multipactor discharge can exist when the multipactor electron energy distribution occurs near E1. The transient nature of such a discharge is shown to result from dynamic changes in E1 due to multipactor conditioning and surface contamination. Experimental data depict transient-mode multipactor (TMM) discharges at a range of rf voltages and chamber pressures for both copper and aluminum electrodes. TMM was detected using a biased current probe, and these events were undetectable by third harmonic diagnostics at chamber pressures below 1×10-3 torr. Discharge parameters such as charge density, period, and duty cycle are shown to be related to both the rf voltage and the chamber pressure. Monte Carlo simulation results support the experimental findings, showing an exponential decrease in the resonant electron population with increasing E1.

  9. Transient Response in LMFBR System.

    1999-04-26

    SSC-L (the Super System Code) calculates the thermohydraulic response of loop-type liquid metal fast breeder reactor (LMFBR) systems during operational, incidental, and accidental transients, especially natural circulation events. Modules simulated and parameters calculated include: core flow rates and temperatures, loop flow rates and temperatures, pump performance, and heat exchanger operation. Additionally, SSC-L accounts for all plant protection and plant control systems. Although the primary emphasis is on transients for safety analysis, SSC-L can be usedmore » for many other applications, such as scoping analysis for plant design and specification of various components. Any number of user-specified loops, pipes, and nodes are permitted. Both single- and two-phase thermal-hydraulics are used in a multi-channel core representation. Inter-assembly flow redistribution is accounted for using a detailed fuel pin model. The heat transport system geometry is user-specified. SSC-L provides steady-state and transient options and a restart capability. Input is free format in a modular structure that makes use of abstract data management techniques.« less

  10. Spectral signatures of penumbral transients

    SciTech Connect

    Reardon, K.; Tritschler, A.

    2013-12-20

    In this work we investigate the properties of penumbral transients observed in the upper photospheric and chromospheric region above a sunspot penumbra using two-dimensional spectroscopic observations of the Ca II 854.21 nm line with a 5 s cadence. In our 30 minutes of observations, we identify several penumbral-micro jets (PMJs) with cotemporal observations from Dunn Solar Telescope/IBIS and Hinode/SOT. We find that the line profiles of these PMJ events show emission in the two wings of the line (±0.05 nm), but little modification of the line core. These are reminiscent of the line profiles of Ellerman bombs observed in plage and network regions. Furthermore, we find evidence that some PMJ events have a precursor phase starting 1 minute prior to the main brightening that might indicate initial heating of the plasma prior to an acoustic or bow shock event. With the IBIS data, we also find several other types of transient brightenings with timescales of less than 1 minute that are not clearly seen in the Hinode/SOT data. The spectral profiles and other characteristics of these events are significantly different from those of PMJs. The different appearances of all these transients are an indicator of the general complexity of the chromospheric magnetic field and underscore the highly dynamic behavior above sunspots. It also highlights the care that is needed in interpreting broadband filter images of chromospheric lines, which may conceal very different spectral profiles, and the underlying physical mechanisms at work.

  11. Analysis of the transient compressible vapor flow in heat pipe

    NASA Technical Reports Server (NTRS)

    Jang, Jong Hoon; Faghri, Amir; Chang, Won Soon

    1989-01-01

    The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds and high mass flow rates are successfully predicted. The one-dimensional model also describes the vapor flow dynamics in cylindrical heat pipes at high temperatures.

  12. Diffuse dispersive delay and the time convolution/attenuation of transients

    NASA Technical Reports Server (NTRS)

    Bittner, Burt J.

    1991-01-01

    Test data and analytic evaluations are presented to show that relatively poor 100 KHz shielding of 12 Db can effectively provide an electromagnetic pulse transient reduction of 100 Db. More importantly, several techniques are shown for lightning surge attenuation as an alternative to crowbar, spark gap, or power zener type clipping which simply reflects the surge. A time delay test method is shown which allows CW testing, along with a convolution program to define transient shielding effectivity where the Fourier phase characteristics of the transient are known or can be broadly estimated.

  13. Transient Characterization of Type B Particles in a Transport Riser

    SciTech Connect

    Shadle, L.J.; Monazam, E.R.; Mei, J.S.

    2007-01-01

    Simple and rapid dynamic tests were used to evaluate fluid dynamic behavior of granular materials in the transport regime. Particles with densities ranging from 189 to 2,500 kg/m3 and Sauter mean size from 61 to 812 μm were tested in a 0.305 m diameter, 15.5 m height circulating fluidized bed (CFB) riser. The transient tests involved the abrupt stoppage of solids flow for each granular material over a wide range gas flow rates. The riser emptying time was linearly related to the Froude number in each of three different operating regimes. The flow structure along the height of the riser followed a distinct pattern as tracked through incremental pressures. These results are discussed to better understand the transformations that take place when operating over various regimes. During the transients the particle size distribution was measured. The effects of pressure, particle size, and density on test performance are also presented.

  14. Benchmarking Of Improved DPAC Transient Deflagration Analysis Code

    SciTech Connect

    Laurinat, James E.; Hensel, Steve J.

    2013-03-21

    The transient deflagration code DPAC (Deflagration Pressure Analysis Code) has been upgraded for use in modeling hydrogen deflagration transients. The upgraded code is benchmarked using data from vented hydrogen deflagration tests conducted at the HYDRO-SC Test Facility at the University of Pisa. DPAC originally was written to calculate peak deflagration pressures for deflagrations in radioactive waste storage tanks and process facilities at the Savannah River Site. Upgrades include the addition of a laminar flame speed correlation for hydrogen deflagrations and a mechanistic model for turbulent flame propagation, incorporation of inertial effects during venting, and inclusion of the effect of water vapor condensation on vessel walls. In addition, DPAC has been coupled with CEA, a NASA combustion chemistry code. The deflagration tests are modeled as end-to-end deflagrations. The improved DPAC code successfully predicts both the peak pressures during the deflagration tests and the times at which the pressure peaks.

  15. Transient creep and semibrittle behavior of crystalline rocks

    USGS Publications Warehouse

    Carter, N.L.; Kirby, S.H.

    1978-01-01

    We review transient creep and semibrittle behavior of crystalline solids. The results are expected to be pertinent to crystalline rocks undergoing deformation in the depth range 5 to 20 km, corresponding to depths of focus of many major earthquakes. Transient creep data for crystalline rocks at elevated temperatures are analyzed but are poorly understood because of lack of information on the deformation processes which, at low to moderate pressure, are likely to be semibrittle in nature. Activation energies for transient creep at high effective confining pressure are much higher than those found for atmospheric pressure tests in which thermally-activated microfracturing probably dominates the creep rate. Empirical transient creep equations are extrapolated at 200?? to 600??C, stresses from 0.1 to 1.0 kbar, to times ranging from 3.17??102 to 3.17??108 years. At the higher temperatures, appreciable transient creep strains may take place but the physical significance of the results is in question because the flow mechanisms have not been determined. The purpose of this paper is to stimulate careful research on this important topic. ?? 1978 Birkha??user Verlag.

  16. Transient and steady-state selection in the striatal microcircuit.

    PubMed

    Tomkins, Adam; Vasilaki, Eleni; Beste, Christian; Gurney, Kevin; Humphries, Mark D

    2013-01-01

    Although the basal ganglia have been widely studied and implicated in signal processing and action selection, little information is known about the active role the striatal microcircuit plays in action selection in the basal ganglia-thalamo-cortical loops. To address this knowledge gap we use a large scale three dimensional spiking model of the striatum, combined with a rate coded model of the basal ganglia-thalamo-cortical loop, to asses the computational role the striatum plays in action selection. We identify a robust transient phenomena generated by the striatal microcircuit, which temporarily enhances the difference between two competing cortical inputs. We show that this transient is sufficient to modulate decision making in the basal ganglia-thalamo-cortical circuit. We also find that the transient selection originates from a novel adaptation effect in single striatal projection neurons, which is amenable to experimental testing. Finally, we compared transient selection with models implementing classical steady-state selection. We challenged both forms of model to account for recent reports of paradoxically enhanced response selection in Huntington's disease patients. We found that steady-state selection was uniformly impaired under all simulated Huntington's conditions, but transient selection was enhanced given a sufficient Huntington's-like increase in NMDA receptor sensitivity. Thus our models provide an intriguing hypothesis for the mechanisms underlying the paradoxical cognitive improvements in manifest Huntington's patients. PMID:24478684

  17. Transient and steady-state selection in the striatal microcircuit.

    PubMed

    Tomkins, Adam; Vasilaki, Eleni; Beste, Christian; Gurney, Kevin; Humphries, Mark D

    2013-01-01

    Although the basal ganglia have been widely studied and implicated in signal processing and action selection, little information is known about the active role the striatal microcircuit plays in action selection in the basal ganglia-thalamo-cortical loops. To address this knowledge gap we use a large scale three dimensional spiking model of the striatum, combined with a rate coded model of the basal ganglia-thalamo-cortical loop, to asses the computational role the striatum plays in action selection. We identify a robust transient phenomena generated by the striatal microcircuit, which temporarily enhances the difference between two competing cortical inputs. We show that this transient is sufficient to modulate decision making in the basal ganglia-thalamo-cortical circuit. We also find that the transient selection originates from a novel adaptation effect in single striatal projection neurons, which is amenable to experimental testing. Finally, we compared transient selection with models implementing classical steady-state selection. We challenged both forms of model to account for recent reports of paradoxically enhanced response selection in Huntington's disease patients. We found that steady-state selection was uniformly impaired under all simulated Huntington's conditions, but transient selection was enhanced given a sufficient Huntington's-like increase in NMDA receptor sensitivity. Thus our models provide an intriguing hypothesis for the mechanisms underlying the paradoxical cognitive improvements in manifest Huntington's patients.

  18. Update on the evaluation of transient vision loss.

    PubMed

    Pula, John H; Kwan, Katherine; Yuen, Carlen A; Kattah, Jorge C

    2016-01-01

    Transient vision loss may indicate underlying vascular disease, including carotid occlusion and thromboembolism, or it may have a more benign etiology, such as migraine or vasospasm. This review focuses on the differential diagnosis and workup of patients presenting with transient vision loss, focusing on several key areas: the relationship to thromboembolic vascular disease, hypercoagulable testing, retinal migraine, and bilateral vision loss. The objective is to provide the ophthalmologist with information on how to best manage these patients. Thromboembolic etiologies for transient vision loss are sometimes managed with medications, but when carotid surgery is indicated, earlier intervention may prevent future stroke. This need for early treatment places the ophthalmologist in the important role of expediting the management process. Hospital admission is recommended in patients presenting with transient symptoms within 72 hours who meet certain high-risk criteria. When the cause is giant cell arteritis, ocular ischemic syndrome, or a cardioembolic source, early management of the underlying condition is equally important. For nonthromboembolic causes of transient vision loss such as retinal migraine or retinal vasospasm, the ophthalmologist can provide reassurance as well as potentially give medications to decrease the frequency of vision loss episodes. PMID:26929593

  19. Update on the evaluation of transient vision loss.

    PubMed

    Pula, John H; Kwan, Katherine; Yuen, Carlen A; Kattah, Jorge C

    2016-01-01

    Transient vision loss may indicate underlying vascular disease, including carotid occlusion and thromboembolism, or it may have a more benign etiology, such as migraine or vasospasm. This review focuses on the differential diagnosis and workup of patients presenting with transient vision loss, focusing on several key areas: the relationship to thromboembolic vascular disease, hypercoagulable testing, retinal migraine, and bilateral vision loss. The objective is to provide the ophthalmologist with information on how to best manage these patients. Thromboembolic etiologies for transient vision loss are sometimes managed with medications, but when carotid surgery is indicated, earlier intervention may prevent future stroke. This need for early treatment places the ophthalmologist in the important role of expediting the management process. Hospital admission is recommended in patients presenting with transient symptoms within 72 hours who meet certain high-risk criteria. When the cause is giant cell arteritis, ocular ischemic syndrome, or a cardioembolic source, early management of the underlying condition is equally important. For nonthromboembolic causes of transient vision loss such as retinal migraine or retinal vasospasm, the ophthalmologist can provide reassurance as well as potentially give medications to decrease the frequency of vision loss episodes.

  20. Update on the evaluation of transient vision loss

    PubMed Central

    Pula, John H; Kwan, Katherine; Yuen, Carlen A; Kattah, Jorge C

    2016-01-01

    Transient vision loss may indicate underlying vascular disease, including carotid occlusion and thromboembolism, or it may have a more benign etiology, such as migraine or vasospasm. This review focuses on the differential diagnosis and workup of patients presenting with transient vision loss, focusing on several key areas: the relationship to thromboembolic vascular disease, hypercoagulable testing, retinal migraine, and bilateral vision loss. The objective is to provide the ophthalmologist with information on how to best manage these patients. Thromboembolic etiologies for transient vision loss are sometimes managed with medications, but when carotid surgery is indicated, earlier intervention may prevent future stroke. This need for early treatment places the ophthalmologist in the important role of expediting the management process. Hospital admission is recommended in patients presenting with transient symptoms within 72 hours who meet certain high-risk criteria. When the cause is giant cell arteritis, ocular ischemic syndrome, or a cardioembolic source, early management of the underlying condition is equally important. For nonthromboembolic causes of transient vision loss such as retinal migraine or retinal vasospasm, the ophthalmologist can provide reassurance as well as potentially give medications to decrease the frequency of vision loss episodes. PMID:26929593

  1. Transient Eddy Current Response Due to a Conductive Cylindrical Rod

    NASA Astrophysics Data System (ADS)

    Fu, Fangwei; Bowler, J. R.

    2007-03-01

    Transient eddy current test systems have been developed for the inspection of aircraft structures and for oil and gas pipelines. This work is supported by theoretical developments in which transient fields and time domain signals are determined for the geometry of interest. However most of the models to date have been aimed at structures that are planar, relatively little attention being paid to the corresponding problems in cylindrical geometries. In order to rectify this deficiency, we have examined theoretically the transient probe signal response due to a cylindrical conductive rod excited by an encircling coil. The transient fields can be calculated from a Fourier transform of the frequency domain solutions for infinite rods or tubes but, as with planar structures, we have found that it is better to use series solutions in the time domain since these provide more accurate and flexible representations of transient fields. Two types of series are used; one which converges faster at short times and one which converges faster at longer times. Calculations using these series show that they are in mutual agreement and agree with results computed using the fast Fourier transform.

  2. Analysis and RHBD technique of single event transients in PLLs

    NASA Astrophysics Data System (ADS)

    Zhiwei, Han; Liang, Wang; Suge, Yue; Bing, Han; Shougang, Du

    2015-11-01

    Single-event transient susceptibility of phase-locked loops has been investigated. The charge pump is the most sensitive component of the PLL to SET, and it is hard to mitigate this effect at the transistor level. A test circuit was designed on a 65 nm process using a new system-level radiation-hardening-by-design technique. Heavy-ion testing was used to evaluate the radiation hardness. Analyses and discussion of the feasibility of this method are also presented.

  3. A transient laboratory method for determining the hydraulic properties of 'tight' rocks-I. Theory

    USGS Publications Warehouse

    Hsieh, P.A.; Tracy, J.V.; Neuzil, C.E.; Bredehoeft, J.D.; Silliman, S.E.

    1981-01-01

    Transient pulse testing has been employed increasingly in the laboratory to measure the hydraulic properties of rock samples with low permeability. Several investigators have proposed a mathematical model in terms of an initial-boundary value problem to describe fluid flow in a transient pulse test. However, the solution of this problem has not been available. In analyzing data from the transient pulse test, previous investigators have either employed analytical solutions that are derived with the use of additional, restrictive assumptions, or have resorted to numerical methods. In Part I of this paper, a general, analytical solution for the transient pulse test is presented. This solution is graphically illustrated by plots of dimensionless variables for several cases of interest. The solution is shown to contain, as limiting cases, the more restrictive analytical solutions that the previous investigators have derived. A method of computing both the permeability and specific storage of the test sample from experimental data will be presented in Part II. ?? 1981.

  4. FibroScan® and transient elastography.

    PubMed

    Kemp, William; Roberts, Stuart

    2013-07-01

    The use of non-invasive tests to stage the severity of liver disease (ie. scarring) is now well established in the management of patients with chronic liver disease. This is because assessment of liver scarring provides prognostic information and assists in establishing treatment priorities. One such technique, transient elastography (TE), is a simple, safe and efficient way to estimate liver scarring. FibroScan® (EchoSens, Paris) is the most popular non-invasive device used to assess liver 'hardness' (or stiffness) via TE in Australia. When performed in the appropriate clinical setting, TE provides a reliable method of detecting cirrhosis and excluding significant fibrosis, particularly when the results are supported by clinical and laboratory data.

  5. Deep level transient spectroscopy in resistive layers

    SciTech Connect

    Hunt, C.E.; Ng, Kim . Dept. of Electrical and Computer Engineering)

    1989-06-01

    This work investigates the application of the Deep Level Transient Spectroscopy (DLTS) technique to resistive semiconductor thin films, such as Silicon-On-Insulator (SOI) and thin layer of GaAs formed on semi-insulating material. Schottky diodes made on these materials were used in this study. The effect of the series resistance inherent in these types of thin-film test structures on the interpretation of data obtained from the measurement apparatus is discussed. It is observed that inverted DLTS signals occur in these structures because of the high series resistance. It is shown that ignoring this effect can lead to erroneous values of the activation energy and the density of traps. 2 refs.

  6. Transient-induced climate drift

    SciTech Connect

    Johansson, A.; Reinhold, B.; Saha, S. )

    1993-05-01

    The climate drift of various quantities associated with deep, planetary-scale, equilibrated, transient Rossby waves are estimated for the Southern Hemisphere extratropical summer as revealed by the DERF II (Dynamical Extended Range Forecasting) dataset. It is found that the vertical structures of these waves systematically become too baroclinic during the course of integration. There are two time scales associated with this climate drift. There is one very short time scale, estimated to be of the order of one day, when the waves become more barotropic. It is followed by a period when the wave baroclinicity monotonically increases, and after roughly 10 days the model structures appear to have reached their statistically equilibrated state. In the meantime, the kinetic energy of the transient waves decreases substantially to roughly half the observed value. After this initial drop, however, the transient kinetic energy increases again, and it is not clear if an equilibrium value has been reached after 30 days, which is the limit of the DERF II dataset. This third time scale is not found in the quantities directly associated with the vertical structures per se, but it is hypothesized to be a consequence of these errors. A theory is utilized that in a simplified way takes into account the processes that determine the vertical structure of baroclinic waves as well as their robustness as a means of understanding the processes leading to these errors. The implications from this theory are that the formulation and magnitude of the dissipative and diffusive processes in the model are the most likely problem, but there are other possibilities. 37 refs., 10 figs.

  7. Transient thermal convection in microgravity

    NASA Technical Reports Server (NTRS)

    Dressler, R. F.

    1981-01-01

    The unsteady two-dimensional thermal convection in a cylinder due to a transient acceleration solved for a step-function excitation. From this, the solution was obtained for an arbitrary time-dependent acceleration. The solutions are valied for sufficiently low Rayleigh numbers and therefore, relevant to microgravity fields. As an example, two graphs are presented for he convection resulting from the movement of an astronaut inside the Shuttle. The analysis can be applied to obtain any other convective flows such as those caused by g-jitter or variable rotation of the Shuttle.

  8. Observations of Solar Radio Transients

    NASA Astrophysics Data System (ADS)

    Paige, Giorla

    2011-05-01

    A low frequency radio telescope has been recently been constructed on the campus of the The College of New Jersey (TCNJ) and has begun conducting observations at 20MHz as part of NASA'a Radio Jove program. This instrument is capable of observations of solar radio emission including strong prompt radio emission associated with solar burst events. We will discuss solar observations conducted with this instrument as well as an effort to conduct coincident observations with the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  9. Transient Wellbore Fluid Flow Model

    1982-04-06

    WELBORE is a code to solve transient, one-dimensional two-phase or single-phase non-isothermal fluid flow in a wellbore. The primary thermodynamic variables used in solving the equations are the pressure and specific energy. An equation of state subroutine provides the density, quality, and temperature. The heat loss out of the wellbore is calculated by solving a radial diffusion equation for the temperature changes outside the bore. The calculation is done at each node point in themore » wellbore.« less

  10. Transient dynamics and the destabilizing effects of prey heterogeneity.

    PubMed

    Steiner, Christopher F; Klausmeier, Christopher A; Litchman, Elena

    2012-03-01

    The presence of prey heterogeneity and weakly interacting prey species is frequently viewed as a stabilizer of predator-prey dynamics, countering the destabilizing effects of enrichment and reducing the amplitude of population cycles. However, prior model explorations have largely focused on long-term, dynamic attractors rather than transient dynamics. Recent theoretical work shows that the presence of prey that are defended from predation can have strongly divergent effects on dynamics depending on time scale: prey heterogeneity can counteract the destabilizing effects of enrichment on predator-prey dynamics at long time scales but strongly destabilize systems during transient phases by creating long periods of low predator/prey abundance and increasing extinction probability (an effect that is amplified with increasing enrichment). We tested these general predictions using a planktonic system composed of a zooplankton predator and multiple algal prey. We first parameterized a model of our system to generate predictions and tested these experimentally. Our results qualitatively supported several model predictions. During transient phases, presence of defended algal prey increased predator extinctions at low and high enrichment levels compared to systems with only a single edible prey. This destabilizing effect was moderated at higher dilution rates, as predicted by our model. When examining dynamics beyond initial oscillations, presence of the defended prey increased predator-prey temporal variability at high nutrient enrichment but had no effect at low nutrient levels. Our results highlight the importance of considering transient dynamics when assessing the role of stabilizing factors on the dynamics of food webs.

  11. Transient Modeling of Hybrid Rocket Low Frequency Instabilities

    NASA Technical Reports Server (NTRS)

    Karabeyoglu, M. Arif; DeZilwa, Shane; Cantwell, Brian; Zilliac, Greg

    2003-01-01

    A comprehensive dynamic model of a hybrid rocket has been developed in order to understand and predict the transient behavior including instabilities. A linearized version of the transient model predicted the low-frequency chamber pressure oscillations that are commonly observed in hybrids. The source of the instabilities is based on a complex coupling of thermal transients in the solid fuel, wall heat transfer blocking due to fuel regression rate and the transients in the boundary layer that forms on the fuel surface. The oscillation frequencies predicted by the linearized theory are in very good agreement with 43 motor test results obtained from the hybrid propulsion literature. The motor test results used in the comparison cover a very wide spectrum of parameters including: 1) four separate research and development programs, 2) three different oxidizers (LOX, GOX, N2O), 3) a wide range of motor dimensions (i.e. from 5 inch diameter to 72 inch diameter) and operating conditions and 4) several fuel formulations. A simple universal scaling formula for the frequency of the primary oscillation mode is suggested.

  12. Transient effects in Herschel/PACS spectroscopy

    NASA Astrophysics Data System (ADS)

    Fadda, Dario; Jacobson, Jeffery D.; Appleton, Philip N.

    2016-10-01

    Context. The Ge:Ga detectors used in the PACS spectrograph onboard the Herschel space telescope react to changes of the incident flux with a certain delay. This generates transient effects on the resulting signal which can be important and last for up to an hour. Aims: The paper presents a study of the effects of transients on the detected signal and proposes methods to mitigate them especially in the case of the unchopped mode. Methods: Since transients can arise from a variety of causes, we classified them in three main categories: transients caused by sudden variations of the continuum due to the observational mode used; transients caused by cosmic ray impacts on the detectors; transients caused by a continuous smooth variation of the continuum during a wavelength scan. We propose a method to disentangle these effects and treat them separately. In particular, we show that a linear combination of three exponential functions is needed to fit the response variation of the detectors during a transient. An algorithm to detect, fit, and correct transient effects is presented. Results: The solution proposed to correct the signal for the effects of transients substantially improves the quality of the final reduction with respect to the standard methods used for archival reduction in the cases where transient effects are most pronounced. Conclusions: The programs developed to implement the corrections are offered through two new interactive data reduction pipelines in the latest releases of the Herschel Interactive Processing Environment.

  13. A transient, quadratic nodal method for triangular-Z geometry

    SciTech Connect

    DeLorey, T.F.

    1993-06-01

    Many systematically-derived nodal methods have been developed for Cartesian geometry due to the extensive interest in Light Water Reactors. These methods typically model the transverse-integrated flux as either an analytic or low order polynomial function of position within the node. Recently, quadratic nodal methods have been developed for R-Z and hexagonal geometry. A static and transient quadratic nodal method is developed for triangular-Z geometry. This development is particularly challenging because the quadratic expansion in each node must be performed between the node faces and the triangular points. As a consequence, in the 2-D plane, the flux and current at the points of the triangles must be treated. Quadratic nodal equations are solved using a non-linear iteration scheme, which utilizes the corrected, mesh-centered finite difference equations, and forces these equations to match the quadratic equations by computing discontinuity factors during the solution. Transient nodal equations are solved using the improved quasi-static method, which has been shown to be a very efficient solution method for transient problems. Several static problems are used to compare the quadratic nodal method to the Coarse Mesh Finite Difference (CMFD) method. The quadratic method is shown to give more accurate node-averaged fluxes. However, it appears that the method has difficulty predicting node leakages near reactor boundaries and severe material interfaces. The consequence is that the eigenvalue may be poorly predicted for certain reactor configurations. The transient methods are tested using a simple analytic test problem, a heterogeneous heavy water reactor benchmark problem, and three thermal hydraulic test problems. Results indicate that the transient methods have been implemented correctly.

  14. Transient simulation of absorption machines

    NASA Astrophysics Data System (ADS)

    Anand, D. K.; Allen, R. W.; Kumar, B.

    1982-08-01

    This paper presents a model for a water-cooled Lithium-Bromide/water absorption chiller and predicts its transient response both during the start-up phase and during the shutoff period. The simulation model incorporates such influencing factors as the thermodynamic properties of the working fluid, the absorbent, the heat-transfer configuration of different components of the chiller and related physical data. The time constants of different components are controlled by a set of key parameters that have been identified in this study. The results show a variable but at times significant amount of time delay before the chiller capacity gets close to its steady-state value. The model is intended to provide an insight into the mechanism of build-up to steady-state performance. By recognizing the significant factors contributing to transient degradation, steps can be taken to reduce such degradation. The evaluation of the residual capacity in the shut-off period will yield more realistic estimates of chiller COP for a chiller satisfying dynamic space cooling load.

  15. PRISMATIC CORE COUPLED TRANSIENT BENCHMARK

    SciTech Connect

    J. Ortensi; M.A. Pope; G. Strydom; R.S. Sen; M.D. DeHart; H.D. Gougar; C. Ellis; A. Baxter; V. Seker; T.J. Downar; K. Vierow; K. Ivanov

    2011-06-01

    The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise.

  16. Special issue on transient plasmas

    NASA Astrophysics Data System (ADS)

    Bailey, James; Hoarty, David; Mancini, Roberto; Yoneda, Hitoki

    2015-11-01

    This special issue of Journal of Physics B: Atomic, Molecular and Optical Physics is dedicated to the "spectroscopy of transient plasmas" covering plasma conditions produced by a range of pulsed laboratory sources including short and long pulse lasers, pulsed power devices, and free electron lasers (FELs). The full range of plasma spectroscopy up to high energy bremsstrahlung radiation, including line broadening analysis for application to data recorded with the ChemCam instrument on the Mars Science Laboratory rover Curiosity, is covered. This issue is timely as advances in optical lasers and x-ray FELs (XFEL) are enabling transient plasma to be probed at higher energies and shorter durations than ever before. New XFEL facilities being commissioned in Europe and Asia are adding to those operating in the US and Japan and the ELI high power laser project in Europe, due to open this year, will provide short pulse lasers of unprecedented power. This special issue represents a snapshot of the theoretical and experimental research in dense plasmas, electron kinetics, laser-induced breakdown spectroscopy of low temperature plasmas, inertial confinement fusion and non-equilibrium atomic physics using spectroscopy to diagnose plasmas produced by optical lasers, XFELs and pulsed-power machines.

  17. Postseismic relaxation and transient creep

    USGS Publications Warehouse

    Savage, J.C.; Svarc, J.L.; Yu, S.-B.

    2005-01-01

    Postseismic deformation has been observed in the epicentral area following the 1992 Landers (M = 7.3), 1999 Chi-Chi (M = 7.6), 1999 Hector Mine (M = 7.1), 2002 Denali (M = 7.9), 2003 San Simeon (M = 6.5), and 2004 Parkfield (M = 6.0) earthquakes. The observations consist of repeated GPS measurements of the position of one monument relative to another (separation ???100 km). The early observations (t < 0.1 year) are well fit by the function a' + c'log(t), where t is the time after the earthquake and a' and c' are constants chosen to fit the data. Because a log(t) time dependence is characteristic of transient (primary) creep, the early postseismic response may be governed by transient creep as Benioff proposed in 1951. That inference is provisional as the stress conditions prevailing in postseismic relaxation are not identical to the constant stress condition in creep experiments. The observed logarithmic time dependence includes no characteristic time that might aid in identifying the micromechanical cause.

  18. UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE

    SciTech Connect

    Sanders, N. E.; Soderberg, A. M.; Betancourt, M.

    2015-02-10

    Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST.

  19. Detection of transient and persistent feline leukaemia virus infections.

    PubMed

    Jarrett, O; Golder, M C; Stewart, M F

    1982-03-01

    A study was made of cats persistently or transiently viraemic with feline leukaemia virus (FeLV) following experimental oronasal infection. Cats of two ages were exposed to the virus. One group was infected when eight weeks old in the expectation that most of the cats would become persistently viraemic, and the second group when 16 weeks old, so that some would show signs of a transient infection and then recover. The periods following infection when virus was detectable in the blood and in the oropharynx were determined for each group. Three methods for detecting viraemia were compared: virus isolation, immunofluorescence on blood smears and an enzyme-linked immunosorbent assay (ELISA). There was good overall agreement among the three tests in detecting virus-positive cats. Virus was found sooner after infection by virus isolation than by the other methods, and virus appeared in the blood slightly sooner in cats which developed persistent viraemia than in transiently viraemic cats. Infectious FeLV was isolated from the oropharynx of all of the persistently viraemic cats, in most cases simultaneously with virus in the plasma. Virus was also isolated from the mouth of most transiently viraemic cats. Under field conditions such transient excretion of virus lasting only a few days would rarely be detected in a single sampling. This might explain how FeLV is maintained in free range urban cats in the absence of a large number of cats with persistent active FeLV infection. For routine diagnosis, immunofluorescence would appear to offer the best chance of differentiating transient and persistent infections by FeLV.

  20. Measurement of calcium transients and slow calcium current in myotubes

    PubMed Central

    1994-01-01

    The purpose of this study was to characterize excitation-contraction (e- c) coupling in myotubes for comparison with e-c coupling of adult skeletal muscle. The whole cell configuration of the patch clamp technique was used in conjunction with the calcium indicator dye Fluo-3 to study the calcium transients and slow calcium currents elicited by voltage clamp pulses in cultured myotubes obtained from neonatal mice. Cells were held at -80 mV and stimulated with 15-20 ms test depolarizations preceded and followed by voltage steps designed to isolate the slow calcium current. The slow calcium current had a threshold for activation of about 0 mV; the peak amplitude of the current reached a maximum at 30 to 40 mV a and then declined for still stronger depolarizations. The calcium transient had a threshold of about -10 mV, and its amplitude increased as a sigmoidal function of test potential and did not decrease again even for test depolarizations sufficiently strong (> or = 50 mV) that the amplitude of the slow calcium current became very small. Thus, the slow calcium current in myotubes appears to have a negligible role in the process of depolarization-induced release of intracellular calcium and this process in myotubes is essentially like that in adult skeletal muscle. After repolarization, however, the decay of the calcium transient in myotubes was very slow (hundreds of ms) compared to adult muscle, particularly after strong depolarizations that triggered larger calcium transients. Moreover, when cells were repolarized after strong depolarizations, the transient typically continued to increase slowly for up to several tens of ms before the onset of decay. This continued increase after repolarization was abolished by the addition of 5 mM BAPTA to the patch pipette although the rapid depolarization-induced release was not, suggesting that the slow increase might be a regenerative response triggered by the depolarization-induced release of calcium. The addition of

  1. Linking transient storage parameters to exchange mechanisms and reach characteristics

    NASA Astrophysics Data System (ADS)

    Morén, Ida; Wörman, Anders; Riml, Joakim

    2015-04-01

    A traditional way of investigating transient storage zones in streams and rivers comprises the performance of tracer tests. The information gained from the tests however, is in many ways limited by the geomorphological and hydraulic local conditions under which the test was performed. Consequently, there is a need for more general information about how reach characteristics and combined exchange mechanisms affect transient storage retention that can be expressed by scaling factors between physical, measurable parameters and the integrated total retention in a reach. A large number of tracer tests have been performed in a wide variety of reaches around the world and in this project we are taking advantage of already collected data as well as new tracer test performed within the study, to quantitatively evaluate how different geomorphic and hydraulic conditions affect the retention of solutes in rivers. By advancing existing physically based models on the local-scale with the combinations of exchange mechanisms we theoretically describe the relative magnitude of exchange mechanisms, and combinations of these, under specific hydraulic conditions and show how exchange parameters associated with different mechanisms are correlated physically. Both hyporheic transient storage zones (HTS) and surface transient storage zones (STS) are considered. Combined vertical exchange with the HTS can be evaluated by superimposing the velocity fields associated with stream features of different size described mathematically by harmonic functions, while exchange with other zones can be treated as independent and after evaluating the relative importance of the associated exchange parameters it can be added to the vertical exchange to obtain the total integrated retention. Based on the tracer tests, each tested reach is characterised in terms of its geomorphologic and hydraulic features and related statistically to reach-scale parameters evaluated from the tests with a longitudinal

  2. Spectroscopic Classifications of Optical Transients with SOAR

    NASA Astrophysics Data System (ADS)

    Foley, R. J.; Hounsell, R. A.; Downing, S.; Pan, Y.-C.; Scolnic, D.; Jha, S. W.; Rest, A.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2015-07-01

    We report the following classifications of optical transients from spectroscopic observations with the Goodman spectrograph (wavelength range 3100 - 7100) on the Southern Astrophysical Research (SOAR) telescope.

  3. A Case of Transient Global Amnesia

    PubMed Central

    Mccroskey, Aidan L.; Deyerle, Branden A.

    2016-01-01

    Transient global amnesia is a clinical syndrome characterized by the sudden onset of anterograde amnesia, accompanied by repetitive questioning, sometimes with a retrograde component, lasting up to 24 hours, without compromise of other neurologic function. Neuroimaging after an acutetransient global amnesia event often shows transient perturbation of specific hippocampal circuits that are involved in memory processing. Critical clinical distinctions, such as between transient global amnesia and other forms of transient amnesic episodes, as well as important clues to the underlying pathophysiologies are herein reviewed. Finally, we discuss the role of hippocampal insufficiency in the neurobiology of delusions. PMID:27354927

  4. Transients with the Fermi GBM

    NASA Astrophysics Data System (ADS)

    Hui, Michelle; Fermi GBM Team

    2016-03-01

    The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky monitoring instrument sensitive to energies from 8 keV to 40 MeV. Its primary science objective is observing gamma-ray bursts (GRBs) in support of the Large Area Telescope, which are both part of the Fermi Gamma-ray Space Telescope. Over the past 7 years of operation, the GBM has detected over 240 GRBs per year and provided timely GCN notices for follow-up observations. In addition to GRBs, Galactic transients, solar flares, and terrestrial gamma-ray flashes have also been observed. With several instruments coming online recently, such as the gravitational wave detectors Advanced LIGO/Virgo and the very high energy surveying instrument HAWC, now is an opportune time for multi-messenger collaboration in counterpart search of gravitational waves and GRBs.

  5. Transient Dendritic Solidification Experiment (TDSE)

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Transient Dendritic Solidification Expepriment (TDSE) is being developed as a candidate for flight aboard the International Space Station. TDSE will study the growth of dendrites (treelike crystalline structures) in a transparent material (succinonitrile or SCN) that mimics the behavior of widely used iron-based metals. Basic work by three Space Shuttle missions of the Isothermal Dendritic Growth Expepriment (IDGE) is yielding new insights into virtually all industrially relevant metal and alloy forming operations. The TDSE is similar to IDGE, but will maintain a constant temperature while varying pressure on the dendrites. Shown here is an exploded view of major elements of TDSE. A similar view is available with labels. The principal investigator is Matthew Koss of College of the Holy Cross in Worcester, MA. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  6. Transient Dendritic Solidification Experiment (TDSE)

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Transient Dendritic Solidification Experiment (TDSE) is being developed as a candidate for flight aboard the International Space Station. TDSE will study the growth of dendrites (treelike crystalline structures) in a transparent material (succinonitrile or SCN) that mimics the behavior or widely used iron-based metals. Basic work by three Space Shuttle missions of the Isothermal Dendritic Growth Experiment (IDGE) is yielding new insights into virtually all industrially relevant metal and alloy forming operations. The TDSE is similar to IDGE, but will maintain a constant temperature while varying pressure on the dendrites. Shown here is an exploded view of major elements of the TDSE. A similar view is availble without labels. The principal investigator is Matthew Koss of College of the Holy Cross in Worcester, MA. Photo credit: NASA/Marshall Space Flight Center (MSFC)

  7. Adaptation to transient postural perturbations

    NASA Technical Reports Server (NTRS)

    Andres, Robert O.

    1992-01-01

    This research was first proposed in May, 1986, to focus on some of the problems encountered in the analysis of postural responses gathered from crewmembers. The ultimate driving force behind this line of research was the desire to treat, predict, or explain 'Space Adaptation Syndrome' (SAS) and hence circumvent any adverse effects of space motion sickness on crewmember performance. The aim of this project was to develop an easily implemented analysis of the transient responses to platform translation that can be elicited with a protocol designed to force sensorimotor reorganization, utilizing statistically reliable criterion measures. This report will present: (1) a summary of the activity that took place in each of the three funded years of the project; (2) discussion of experimental results and their implications for future research; and (3) a list of presentations and publications resulting from this project.

  8. X33 Transient Liftoff Analysis

    NASA Technical Reports Server (NTRS)

    Peck, Jeff; Brunty, Joseph

    2000-01-01

    The successful design of a launch vehicle requires the careful characterization of the various loads the structure will experience over its lifetime. Many of the most demanding load environments occur during the launch/ascent phase of a mission, typically defined as the point of engine start through engine cut off. One of the critical events during the launch phase is the liftoff event. This event imparts high loads on the vehicle due to transient events such as thrust build-up and vehicle release. This paper describes the theory and procedures used to calculate structural loads due to the liftoff event for the Lockheed-Martin X33 technology demonstrator vehicle. These procedures were developed at NASA's Marshall Space Flight Center and verified previously on other advanced launch system concepts and the Space Shuttle system.

  9. SSME turbopump technology improvements via transient rotordynamic analysis

    NASA Technical Reports Server (NTRS)

    Childs, D. W.

    1975-01-01

    The rotordynamic behavior of the high pressure oxygen turbopump and high pressure fuel pump was analyzed for the Space Shuttle Main Engine. The identification of potential rotordynamic problem areas which might arise during operation of these units prior to their testing was accomplished. Alternative procedures for correcting potential rotordynamic problems should they occur were investigated. An adequate analytic and physical understanding of the turbopump rotordynamics was developed to improve the probability of a correct diagnosis of rotordynamic problems from test data. Transient rotordynamic models were developed for both turbopumps. The transient models model the hydrodynamic forces of the turbopump seals. A linear stability analysis was performed for the turbopump rotordynamics models, which included gyroscopic effects, seal forces, speed-dependent bearing characteristics, and internal rotor damping. Results are presented and discussed.

  10. Retinal mesopic adaptation model for brightness perception under transient glare.

    PubMed

    Barrionuevo, Pablo Alejandro; Colombo, Elisa Margarita; Issolio, Luis Alberto

    2013-06-01

    A glare source in the visual field modifies the brightness of a test patch surrounded by a mesopic background. In this study, we investigated the effect of two levels of transient glare on brightness perception for several combinations of mesopic reference test luminances (Lts) and background luminances (Lbs). While brightness perception was affected by Lb, there were no appreciable effects for changes in the Lt. The highest brightness reduction was found for Lbs in the low mesopic range. Considering the main proposal that brightness can be inferred from contrast and the Lb sets the mesopic luminance adaptation, we hypothesized that contrast gain and retinal adaptation mechanisms would act when a transient glare source was present in the visual field. A physiology-based model that adequately fitted the present and previous results was developed.

  11. Transient apical breakdown following subluxation injury: a case report.

    PubMed

    Boyd, K S

    1995-02-01

    Transient apical breakdown has been reported to occur in cases in which a periapical radiolucency develops and resolves without treatment following luxation injury. Diagnostic errors are inevitable if periapical breakdown is used as the sole criterion or as an overriding criterion in the decision to initiate root canal treatment. A clinical case report is presented in which transient apical breakdown occurred after a subluxation injury. The threshold to sensitivity tests increased yet sensitivity remained positive with the appearance of the periapical radiolucency. The decision was made not to initiate root canal treatment in spite of the radiographic appearance periapically. At the 10-month recall the tooth remained responsive to sensitivity tests and the apical radiolucency had disappeared.

  12. Cool and Luminous Transients from Mass-Losing Binary Stars

    NASA Astrophysics Data System (ADS)

    Pejcha, Ondrej; Metzger, Brian D.; Tomida, Kengo

    2016-01-01

    We study transients produced by equatorial disk-like outflows from catastrophically mass-losing binary stars with an asymptotic velocity and energy deposition rate near the inner edge which are proportional to the binary escape velocity. As a test case, we present the first smoothed-particle radiation-hydrodynamics calculations of the mass loss from the outer Lagrange point with realistic equation of state and opacities. The mass-losing binary outflows produce luminosities reaching up to 106 L⊙ and the effective temperatures are between 500 and 6000 K, which is compatible with those of many of the class of recently-discovered red transients such as V838 Mon and V1309 Sco. Dust readily forms in the outflow, potentially in a catastrophic global cooling transition. The appearance of the transient is viewing angle-dependent due to vastly different optical depths parallel and perpendicular to the binary plane. We predict a correlation between the peak luminosity and the outflow velocity, which is roughly obeyed by the known red transients.

  13. Interferometric Radio Transient Reconstruction in Compressed Sensing Framework

    NASA Astrophysics Data System (ADS)

    Jiang, M.; Girard, J. N.; Starck, J.-L.; Corbel, S.; Tasse, C.

    2015-12-01

    Imaging by aperture synthesis from interferometric data is a well-known, but strong ill-posed inverse problem. Strong and faint radio sources can be imaged unambiguously using time and frequency integration to gather more Fourier samples of the sky. , However, these imagers assumes a steady sky and the complexity of the problem increases when transients radio sources are also present in the data. Hopefully, in the context of transient imaging, the spatial and temporal information are separable which enable extension of an imager fit for a steady sky. We introduce independent spatial and temporal wavelet dictionaries to sparsely represent the transient in both spatial domain and temporal domain. These dictionaries intervenes in a new reconstruction method developed in the Compressed Sensing (CS) framework and using a primal-dual splitting algorithm. According to the preliminary tests in different noise regimes, this new ``Time-agile'' (or 2D-1D) method seems to be efficient in detecting and reconstructing the transients temporal dependence.

  14. A space-based radio frequency transient event classifier

    SciTech Connect

    Moore, K.R.; Blain, C.P.; Caffrey, M.P.; Franz, R.C.; Henneke, K.M.; Jones, R.G.

    1998-03-01

    The Department of Energy is currently investigating economical and reliable techniques for space-based nuclear weapon treaty verification. Nuclear weapon detonations produce RF transients that are signatures of illegal nuclear weapons tests. However, there are many other sources of RF signals, both natural and man-made. Direct digitization of RF signals requires rates of 300 MSamples per second and produces 10{sup 13} samples per day of data to analyze. it is impractical to store and downlink all digitized RF data from such a satellite without a prohibitively expensive increase in the number and capacities of ground stations. Reliable and robust data processing and information extraction must be performed onboard the spacecraft in order to reduce downlinked data to a reasonable volume. The FORTE (Fast On-Orbit Recording of Transient Events) satellite records RF transients in space. These transients will be classified onboard the spacecraft with an Event Classifier specialized hardware that performs signal preprocessing and neural network classification. The authors describe the Event Classifier requirements, scientific constraints, design and implementation.

  15. Analysis of electrical transients created by lightning

    NASA Technical Reports Server (NTRS)

    Nanevicz, J. E.; Vance, E. F.

    1980-01-01

    A series of flight tests was conducted using a specially-instrumented NASA Learjet to study the electrical transients created on an aircraft by nearby lightning. The instrumentation included provisions for the time-domain and frequency-domain recording of the electrical signals induced in sensors located both on the exterior and on the interior of the aircraft. The design and calibration of the sensors and associated measuring systems is described together with the results of the flight test measurements. The results indicate that the concept of providing instrumentation to follow the lightning signal from propagation field, to aircraft skin current, to current on interior wiring is basically sound. The results of the measurement indicate that the high frequency signals associated with lightning stroke precursor activity are important in generating electromagnetic noise on the interior of the aircraft. Indeed, the signals produced by the precursors are often of higher amplitude and of longer duration that the pulse produced by the main return stroke.

  16. Transient Study of a Cryogenic Hydrogen Filling System

    NASA Technical Reports Server (NTRS)

    Schleier, Howard

    1991-01-01

    An investigation was made of producing a workable model for the transient analysis of a cryogenic hydrogen filling system. A series of programs and subprograms defining the momentum, mass, and energy balances and the physical properties, transport properties, and their interactions were devised.The program was modified for a simple theoretical test fluid. Exhaustive runs and modifications were made and at this point no stability was achieved except in trivial cases.

  17. A hybrid transfinite element approach for nonlinear transient thermal analysis

    NASA Technical Reports Server (NTRS)

    Tamma, Kumar K.; Railkar, Sudhir B.

    1987-01-01

    A new computational approach for transient nonlinear thermal analysis of structures is proposed. It is a hybrid approach which combines the modeling versatility of contemporary finite elements in conjunction with transform methods and classical Bubnov-Galerkin schemes. The present study is limited to nonlinearities due to temperature-dependent thermophysical properties. Numerical test cases attest to the basic capabilities and therein validate the transfinite element approach by means of comparisons with conventional finite element schemes and/or available solutions.

  18. Nodal integral method for transient heat conduction in a cylinder

    SciTech Connect

    Esser, P.D. )

    1993-01-01

    The accuracy and efficiency of nodal solution methods are well established for neutron diffusion in a variety of geometries, as well as for heat transfer and fluid flow in rectangular coordinates. This paper describes the development of a nodal integral method to solve the transient heat conduction equation in cylindrical geometry. Results for a test problem with an analytical solution indicate that the nodal solution provides higher accuracy than a conventional implicit finite difference scheme, while maintaining similar stability characteristics.

  19. Analog-digital simulation of transient-induced logic errors and upset susceptibility of an advanced control system

    NASA Technical Reports Server (NTRS)

    Carreno, Victor A.; Choi, G.; Iyer, R. K.

    1990-01-01

    A simulation study is described which predicts the susceptibility of an advanced control system to electrical transients resulting in logic errors, latched errors, error propagation, and digital upset. The system is based on a custom-designed microprocessor and it incorporates fault-tolerant techniques. The system under test and the method to perform the transient injection experiment are described. Results for 2100 transient injections are analyzed and classified according to charge level, type of error, and location of injection.

  20. Analysis of tracer and thermal transients during reinjection

    SciTech Connect

    Kocabas, I.

    1989-10-01

    This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.

  1. Incipient Transient Detection in Reactor Systems: Experimental and Theoretical Investigation

    SciTech Connect

    Lefteri H. Tsoukalas; S.T. Revankar; X Wang; R. Sattuluri

    2005-09-27

    The main goal of this research was to develop a method for detecting reactor system transients at the earliest possible time through a comprehensive experimental, testing and benchmarking program. This approach holds strong promise for developing new diagnostic technologies that are non-intrusive, generic and highly portable across different systems. It will help in the design of new generation nuclear power reactors, which utilize passive safety systems with a reliable and non-intrusive multiphase flow diagnostic system to monitor the function of the passive safety systems. The main objective of this research was to develop an improved fuzzy logic based detection method based on a comprehensive experimental testing program to detect reactor transients at the earliest possible time, practically at their birth moment. A fuzzy logic and neural network based transient identification methodology and implemented in a computer code called PROTREN was considered in this research and was compared with SPRT (Sequentially Probability Ratio Testing) decision and Bayesian inference. The project involved experiment, theoretical modeling and a thermal-hydraulic code assessment. It involved graduate and undergraduate students participation providing them with exposure and training in advanced reactor concepts and safety systems. In this final report, main tasks performed during the project period are summarized and the selected results are presented. Detailed descriptions for the tasks and the results are presented in previous yearly reports (Revankar et al 2003 and Revankar et al 2004).

  2. Transient global amnesia: an extensive case report.

    PubMed Central

    Gordon, B; Marin, O S

    1979-01-01

    A case of transient global amnesia was studied in detail. Of note was a temporally extensive, although quite patchy, retrograde amnesia during the event for information recallable at other times. While a consolidation block can explain the anterograde amnesia in transient global amnesia, the profound retrograde amnesia requires an additional block in the retrieval of old, established memories. PMID:469566

  3. Transient thermal stress recovery for structural models

    NASA Technical Reports Server (NTRS)

    Walls, William

    1992-01-01

    A method for computing transient thermal stress vectors from temperature vectors is described. The three step procedure involves the use of NASTRAN to generate an influence coefficient matrix which relates temperatures to stresses in the structural model. The transient thermal stresses are then recovered and sorted for maximum and minimum values. Verification data for the procedure is also provided.

  4. Transient repression of the lac operon.

    PubMed

    Tyler, B; Loomis, W F; Magasanik, B

    1967-12-01

    Severe transient repression of constitutive or induced beta-galactosidase synthesis occurs upon the addition of glucose to cells of Escherichia coli growing on glycerol, succinic acid, or lactic acid. Only mutants particularily well adapted to growth on glucose exhibit this phenomenon when transferred to a glucose-containing medium. No change in ribonucleic acid (RNA) metabolism was observed during transient repression. We could show that transient repression is pleiotropic, affecting all products of the lac operon. It occurs in a mutant insensitive to catabolite repression. It is established much more rapidly than catabolite repression, and is elicited by glucose analogues that are phosphorylated but not further catabolized by the cell. Thus, transient repression is not a consequence of the exclusion of inducer from the cell, does not require catabolism of the added compound, and does not involve a gross change in RNA metabolism. We conclude that transient repression is distinct from catabolite repression. PMID:4864411

  5. Synchronizing noisy nonidentical oscillators by transient uncoupling

    NASA Astrophysics Data System (ADS)

    Tandon, Aditya; Schröder, Malte; Mannattil, Manu; Timme, Marc; Chakraborty, Sagar

    2016-09-01

    Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed "generalized synchronization." Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the units stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.

  6. Transient Eddies in the UCLA GCM

    NASA Technical Reports Server (NTRS)

    White, G. H.

    1985-01-01

    The simulation of transient eddies in the nine level UCLA general circulation model (GCM) was examined and compared to observations, with emphasis on the Northern Hemisphere winter. Qualitatively, the UCLA GCM reproduces many features of the observed circulation and the relationship between the time mean flow and transient eddies; however, the magnitudes of transient eddies in the UCLA GCM, particularly at frequencies lower than those associated with baroclinic instability, appear to be much less than those observed. The pattern of low level transient eddy heat fluxes were similar to observations and acted to dissipate the low level seasonal mean temperature field. The simulated transient eddy kinetic energy at 300 mb is given for eddies of all time scales shorter than a season.

  7. Galactic transients from the OGLE survey

    NASA Astrophysics Data System (ADS)

    Mroz, Przemek

    2016-07-01

    For many years, there were not any systematic, large-scale surveys for transients in the Milky Way and the Magellanic Clouds. This gap is being filled by discoveries from the OGLE survey, which has been regularly monitoring the densest sky regions (the Galactic bulge and disk, the Magellanic System) for over twenty years. The OGLE collection of Galactic transients contains several dozen classical novae and over a thousand other cataclysmic variables. I will tell how to select transients from billions of sources observed by the OGLE every night. I will show how the properties of classical novae depend on the underlying stellar population (and the star formation history). I will also discuss the preliminary results of the search for transients in the Milky Way disk from the OGLE-IV Galaxy Variability Survey. Finally, I will show some transients of yet unknown origin and present the OGLE-IV real time monitoring systems.

  8. Current status of the Explosive Transient Camera. [automated sky survey instument sensitive to optical transients

    NASA Technical Reports Server (NTRS)

    Vanderspek, Roland; Doty, John P.; Ricker, George R.

    1992-01-01

    The current configuration and performance of the Explosive Transient Camera (ETC), a wide-field sky monitor capable of detecting short-timescale optical transients, are briefly reviewed, as are plans for future improvements. The primary objective of the ETC is to detect an optical transient that is spatially and temporally coincident with a gamma-ray burster. However, the ETC is sensitive to all sources of short-timescale optical transients and will conduct a systematic survey of the night sky for all optical transients. Results of preliminary observations of the night sky conducted since January 1991 are summarized, and long-term variability searches with the ETC are discussed.

  9. Cool and luminous transients from mass-losing binary stars

    NASA Astrophysics Data System (ADS)

    Pejcha, Ondřej; Metzger, Brian D.; Tomida, Kengo

    2016-02-01

    We study transients produced by equatorial disc-like outflows from catastrophically mass-losing binary stars with an asymptotic velocity and energy deposition rate near the inner edge which are proportional to the binary escape velocity vesc. As a test case, we present the first smoothed-particle radiation-hydrodynamics calculations of the mass loss from the outer Lagrange point with realistic equation of state and opacities. The resulting spiral stream becomes unbound for binary mass ratios 0.06 ≲ q ≲ 0.8. For synchronous binaries with non-degenerate components, the spiral-stream arms merge at a radius of ˜10a, where a is the binary semi-major axis, and the accompanying shock thermalizes about 10 per cent of the kinetic power of the outflow. The mass-losing binary outflows produce luminosities reaching up to ˜106 L⊙ and effective temperatures spanning 500 ≲ Teff ≲ 6000 K, which is compatible with many of the class of recently discovered red transients such as V838 Mon and V1309 Sco. Dust readily forms in the outflow, potentially in a catastrophic global cooling transition. The appearance of the transient is viewing angle-dependent due to vastly different optical depths parallel and perpendicular to the binary plane. We predict a correlation between the peak luminosity and the outflow velocity, which is roughly obeyed by the known red transients. Outflows from mass-losing binaries can produce luminous (105 L⊙) and cool (Teff ≲ 1500 K) transients lasting a year or longer, as has potentially been detected by Spitzer surveys of nearby galaxies.

  10. Investigation of the transient aerodynamic phenomena associated with passing manoeuvres

    NASA Astrophysics Data System (ADS)

    Noger, C.; Regardin, C.; Széchényi, E.

    2005-11-01

    Passing manoeuvres and crosswind can have significant effects on the stability of road vehicles. The transient aerodynamics, which interacts with suspension, steering geometry and driver reaction is not well understood. When two vehicles overtake or cross, they mutually influence the flow field around each other, and under certain conditions, can generate severe gust loads that act as additional forces on both vehicles. The transient forces acting on them are a function of the longitudinal and transverse spacings and of the relative velocity between the two vehicles. Wind tunnel experiments have been conducted in one of the automotive wind tunnels of the Institut Aérotechnique of Saint-Cyr l’École to simulate the transient overtaking process between two models of a simple generic automobile shape. The tests were designed to study the effects of various parameters such as the longitudinal and transverse spacing, the relative velocity and the crosswind on the aerodynamic forces and moments generated on the overtaken and overtaking vehicles. Test results characterize the transient aerodynamic side force as well as the yawing moment coefficients in terms of these parameters. Measurements of the drag force coefficient as well as the static pressure distribution around the overtaken vehicle complete the understanding. The main results indicate the aerodynamic coefficients of the overtaken vehicle to be velocity independent within the limit of the test parameters, while unsteady aerodynamic effects appear in the case of an overtaking vehicle. The mutual interference effects between the vehicles vary as a linear function of the transverse spacing and the crosswind does not really generate any new unsteady behaviour.

  11. Transient shocks beyond the heliopause

    SciTech Connect

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    2015-09-30

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may be interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.

  12. Transient shocks beyond the heliopause

    DOE PAGES

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    2015-09-30

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may bemore » interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.« less

  13. POET: POlarimeters for Energetic Transients

    NASA Technical Reports Server (NTRS)

    Hill, J. E.; McConnell, M. L.; Bloser, P.; Legere, J.; Macri, J.; Ryan, J.; Barthelmy, S.; Angelini, L.; Sakamoto, T.; Black, J. K.; Hartmann, D. H.; Kaaret, P.; Zhang, B.; Ioka, K.; Nakamura, T.; Toma, K.; Yamazaki, R.; Wu, X.

    2008-01-01

    POET (Polarimeters for Energetic Transients) is a Small Explorer mission concept proposed to NASA in January 2008. The principal scientific goal of POET is to measure GRB polarization between 2 and 500 keV. The payload consists of two wide FoV instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2-15 keV and a high energy polarimeter (Gamma-Ray Polarimeter Experiment - GRAPE) that will measure polarization in the 60-500 keV energy range. Spectra will be measured from 2 keV up to 1 MeV. The POET spacecraft provides a zenith-pointed platform for maximizing the exposure to deep space. Spacecraft rotation will provide a means of effectively dealing with systematics in the polarization response. POET will provide sufficient sensitivity and sky coverage to measure statistically significant polarization for up to 100 GRBs in a two-year mission. Polarization data will also be obtained for solar flares, pulsars and other sources of astronomical interest.

  14. Transient liquid phase ceramic bonding

    DOEpatents

    Glaeser, Andreas M.

    1994-01-01

    Ceramics are joined to themselves or to metals using a transient liquid phase method employing three layers, one of which is a refractory metal, ceramic or alloy. The refractory layer is placed between two metal layers, each of which has a lower melting point than the refractory layer. The three layers are pressed between the two articles to be bonded to form an assembly. The assembly is heated to a bonding temperature at which the refractory layer remains solid, but the two metal layers melt to form a liquid. The refractory layer reacts with the surrounding liquid and a single solid bonding layer is eventually formed. The layers may be designed to react completely with each other and form refractory intermetallic bonding layers. Impurities incorporated into the refractory metal may react with the metal layers to form refractory compounds. Another method for joining ceramic articles employs a ceramic interlayer sandwiched between two metal layers. In alternative embodiments, the metal layers may include sublayers. A method is also provided for joining two ceramic articles using a single interlayer. An alternate bonding method provides a refractory-metal oxide interlayer placed adjacent to a strong oxide former. Aluminum or aluminum alloys are joined together using metal interlayers.

  15. Monitoring of Transient Lunar Phenomena

    NASA Astrophysics Data System (ADS)

    Barker, Timothy; Farber, Ryan; Ahrendts, Gary

    2014-06-01

    Transient Lunar Phenomena (TLP’s) are described as short-lived changes in the brightness of areas on the face of the Moon. TLP research is characterized by the inability to substantiate, reproduce, and verify findings. Our current research includes the analysis of lunar images taken with two Santa Barbara Instrument Group (SBIG) ST8-E CCD cameras mounted on two 0.36m Celestron telescopes. On one telescope, we are using a sodium filter, and on the other an H-alpha filter, imaging approximately one-third of the lunar surface. We are focusing on two regions: Hyginus and Ina. Ina is of particular interest because it shows evidence of recent activity (Schultz, P., Staid, M., Pieters, C. Nature, Volume 444, Issue 7116, pp. 184-186, 2006). A total of over 50,000 images have been obtained over approximately 35 nights and visually analyzed to search for changes. As of March, 2014, no evidence of TLPs has been found. We are currently developing a Matlab program to do image analysis to detect TLPs that might not be apparent by visual inspection alone.

  16. Transient shocks beyond the heliopause

    NASA Astrophysics Data System (ADS)

    Fermo, R. L.; Pogorelov, N. V.; Burlaga, L. F.

    2015-09-01

    The heliopause is a rich, dynamic surface affected by the time-dependent solar wind. Stream interactions due to coronal mass ejections (CMEs), corotating interaction regions (CIRs), and other transient phenomena are known to merge producing global merged interaction regions (GMIRs). Numerical simulations of the solar wind interaction with the local interstellar medium (LISM) show that GMIRs, as well other time-dependent structures in the solar wind, may produce compression/rarefaction waves and shocks in the LISM behind the heliopause. These shocks may initiate wave activity observed by the Voyager spacecraft. The magnetometer onboard Voyager 1 indeed observed a few structures that may be interpreted as shocks. We present numerical simulations of such shocks in the year of 2000, when both Voyager spacecraft were in the supersonic solar wind region, and in 2012, when Voyager 1 observed traveling shocks. In the former case, Voyager observations themselves provide time- dependent boundary conditions in the solar wind. In the latter case, we use OMNI data at 1 AU to analyze the plasma and magnetic field behavior after Voyager 1 crossed the heliospheric boundary. Numerical results are compared with spacecraft observations.

  17. Experimental study of transient liquid motion in orbiting spacecraft

    NASA Technical Reports Server (NTRS)

    Berry, R. L.; Tegart, J. R.

    1975-01-01

    The results are presented of a twofold study of transient liquid motion such as that which will be experienced during orbital maneuvers by space tug. A test program was conducted in a low-g test facility involving twenty-two drops. Biaxial, low-g accelerations were applied to an instrumented, model propellant tank during free-fall testing, and forces exerted during liquid reorientation were measured and recorded. Photographic records of the liquid reorientation were also made. The test data were used to verify a mechanical analog which portrays the liquid as a point mass moving on an ellipsoidal constraint surface. The mechanical analog was coded into a FORTRAN IV digital computer program: LAMPS, Large AMPlitude Slosh. Test/analytical correlation indicates that the mechanical analog is capable of predicting the overall force trends measured during testing.

  18. Experimental research on transient radiation effects in microprocessors based on SPARC-V8 architecture

    NASA Astrophysics Data System (ADS)

    Yuanfu, Zhao; Hongchao, Zheng; Long, Fan; Suge, Yue; Maoxin, Chen; Shougang, Du

    2015-11-01

    An experimental system is developed for the transient radiation effects testing of an anti-radiation hardened processor. Based on this system, the transient radiation effects in a microprocessor based on SPARC-V8 architecture was investigated. The dose-rate-soft-error index parameters of the processor were determined according to the test results, as were the influences on the function and timing parameters of the processor. The power supply balance is affected, which caused the system to reset and be the main source of soft errors. The results showed the circuit recovery time is primarily determined by the internal PLL, while the core power and the output-low-IO ports are more sensitive to the transient dose rate effect. The power-integrity-hardened design is proposed to mitigate the transient radiation effect.

  19. Beam-Switch Transient Effects in the RF Path of the ICAPA Receive Phased Array Antenna

    NASA Technical Reports Server (NTRS)

    Sands, O. Scott

    2003-01-01

    When the beam of a Phased Array Antenna (PAA) is switched from one pointing direction to another, transient effects in the RF path of the antenna are observed. Testing described in the report has revealed implementation-specific transient effects in the RF channel that are associated with digital clocking pulses that occur with transfer of data from the Beam Steering Controller (BSC) to the digital electronics of the PAA under test. The testing described here provides an initial assessment of the beam-switch phenomena by digitally acquiring time series of the RF communications channel, under CW excitation, during the period of time that the beam switch transient occurs. Effects are analyzed using time-frequency distributions and instantaneous frequency estimation techniques. The results of tests conducted with CW excitation supports further Bit-Error-Rate (BER) testing of the PAA communication channel.

  20. Apparatus Characterizes Transient Voltages in Real Time

    NASA Technical Reports Server (NTRS)

    Medelius, Pedro

    2005-01-01

    The figure shows a prototype of a relatively inexpensive electronic monitoring apparatus that measures and records selected parameters of lightning-induced transient voltages on communication and power cables. The selected parameters, listed below, are those most relevant to the ability of lightning-induced transients to damage electronic equipment. This apparatus bridges a gap between some traditional transient-voltage recorders that record complete waveforms and other traditional transient-voltage recorders that record only peak values: By recording the most relevant parameters and only those parameters this apparatus yields more useful information than does a traditional peak-value (only) recorder while imposing much smaller data-storage and data-transmission burdens than does a traditional complete-waveform recorder. Also, relative to a complete-waveform recorder, this apparatus is more reliable and can be built at lower cost because it contains fewer electronic components. The transients generated by sources other than lightning tend to have frequency components well below 1 MHz. Most commercial transient recorders can detect and record such transients, but cannot respond rapidly enough for recording lightning-induced transient voltage peaks, which can rise from 10 to 90 percent of maximum amplitude in a fraction of a microsecond. Moreover, commercial transient recorders cannot rearm themselves rapidly enough to respond to the multiple transients that occur within milliseconds of each other on some lightning strikes. One transient recorder, designed for Kennedy Space Center earlier [ Fast Transient-Voltage Recorder (KSC- 11991), NASA Tech Briefs, Vol. 23, No. 10, page 6a (October 1999)], is capable of sampling transient voltages at peak values up to 50 V in four channels at a rate of 20 MHz. That recorder contains a trigger circuit that continuously compares the amplitudes of the signals on four channels to a preset triggering threshold. When a trigger signal

  1. Passive transient transfer of peanut allergy by liver transplantation.

    PubMed

    Dewachter, P; Vézinet, C; Nicaise-Roland, P; Chollet-Martin, S; Eyraud, D; Creusvaux, H; Vaillant, J C; Mouton-Faivre, C

    2011-07-01

    We report a case of transient symptomatic transferred IgE-mediated peanut allergy after elective blood-group compatible liver transplantation. We show that the allergy was transient and therefore passive, authorizing further uneventful peanut consumption. Skin tests with commercial peanut extract and native peanut were performed in the recipient. Circulating specific IgE against peanut and recombinant peanut allergens (rArah1, rArah2, rArah3) was measured in stored serum samples collected from the recipient between 6 months before and 8 months after liver transplantation. Specific IgE levels in the donor were measured at the time of multiorgan donation. In the recipient, diagnosis of IgE-mediated peanut anaphylaxis was based on the clinical history and detection of specific IgE against peanut and recombinant major peanut allergens (rArah1, rArah2 and rArah3). Skin tests were negative and specific IgE undetectable 6 months after the clinical reaction. Oral peanut challenge was negative excluding persistent peanut allergy. This case confirms that IgE-mediated peanut allergy can be transferred by liver transplantation and shows that it may be transient and therefore passively acquired.

  2. Transient critical heat flux and blowdown heat-transfer studies

    SciTech Connect

    Leung, J.C.

    1980-05-01

    Objective of this study is to give a best-estimate prediction of transient critical heat flux (CHF) during reactor transients and hypothetical accidents. To accomplish this task, a predictional method has been developed. Basically it involves the thermal-hydraulic calculation of the heated core with boundary conditions supplied from experimental measurements. CHF predictions were based on the instantaneous ''local-conditions'' hypothesis, and eight correlations (consisting of round-tube, rod-bundle, and transient correlations) were tested against most recent blowdown heat-transfer test data obtained in major US facilities. The prediction results are summarized in a table in which both CISE and Biasi correlations are found to be capable of predicting the early CHF of approx. 1 s. The Griffith-Zuber correlation is credited for its prediction of the delay CHF that occurs in a more tranquil state with slowly decaying mass velocity. In many instances, the early CHF can be well correlated by the x = 1.0 criterion; this is certainly indicative of an annular-flow dryout-type crisis. The delay CHF occurred at near or above 80% void fraction, and the success of the modified Zuber pool-boiling correlation suggests that this CHF is caused by flooding and pool-boiling type hydrodynamic crisis.

  3. Determination of Coal Permeability Using Pressure Transient Methods

    SciTech Connect

    McLendon, T.R.; Siriwardane, H.; Haljasmaa, I.V.; Bromhal, G.S.; Soong, Y.; Irdi, G.A.

    2007-05-01

    Coalbed methane is a significant natural resource in the Appalachian region. It is believed that coalbed methane production can be enhanced by injection of carbon dioxide into coalbeds. However, the influence of carbon dioxide injection on coal permeability is not yet well understood. Competitive sorption of carbon dioxide and methane gases onto coal is a known process. Laboratory experiments and limited field experience indicate that coal will swell during sorption of a gas and shrink during desorption of a gas. The swelling and shrinkage may change the permeability of the coal. In this study, the permeability of coal was determined by using carbon dioxide as the flowing fluid. Coal samples with different dimensions were prepared for laboratory permeability tests. Carbon dioxide was injected into the coal and the permeability was determined by using pressure transient methods. The confining pressure was variedto cover a wide range of depths. The permeability was also determined as a function of exposure time of carbon dioxide while the confining stress was kept constant. CT scans were taken before and after the introduction of carbon dioxide. Results show that the porosity and permeability of the coal matrix was very low. The paper presents experimental data and theoretical aspects of the flow of carbon dioxide through a coal sample during pressure transient tests. The suitability of the pressure transient methods for determining permeability of coal during carbon dioxide injection is discussed in the paper.

  4. Passive transient transfer of peanut allergy by liver transplantation.

    PubMed

    Dewachter, P; Vézinet, C; Nicaise-Roland, P; Chollet-Martin, S; Eyraud, D; Creusvaux, H; Vaillant, J C; Mouton-Faivre, C

    2011-07-01

    We report a case of transient symptomatic transferred IgE-mediated peanut allergy after elective blood-group compatible liver transplantation. We show that the allergy was transient and therefore passive, authorizing further uneventful peanut consumption. Skin tests with commercial peanut extract and native peanut were performed in the recipient. Circulating specific IgE against peanut and recombinant peanut allergens (rArah1, rArah2, rArah3) was measured in stored serum samples collected from the recipient between 6 months before and 8 months after liver transplantation. Specific IgE levels in the donor were measured at the time of multiorgan donation. In the recipient, diagnosis of IgE-mediated peanut anaphylaxis was based on the clinical history and detection of specific IgE against peanut and recombinant major peanut allergens (rArah1, rArah2 and rArah3). Skin tests were negative and specific IgE undetectable 6 months after the clinical reaction. Oral peanut challenge was negative excluding persistent peanut allergy. This case confirms that IgE-mediated peanut allergy can be transferred by liver transplantation and shows that it may be transient and therefore passively acquired. PMID:21668638

  5. Inferring directional interactions from transient signals with symbolic transfer entropy

    NASA Astrophysics Data System (ADS)

    Martini, Marcel; Kranz, Thorsten A.; Wagner, Tobias; Lehnertz, Klaus

    2011-01-01

    We extend the concept of symbolic transfer entropy to enable the time-resolved investigation of directional relationships between coupled dynamical systems from short and transient noisy time series. For our approach, we consider an observed ensemble of a sufficiently large number of time series as multiple realizations of a process. We derive an index that quantifies the preferred direction of transient interactions and assess its significance using a surrogate-based testing scheme. Analyzing time series from noisy chaotic systems, we demonstrate numerically the applicability and limitations of our approach. Our findings obtained from an analysis of event-related brain activities underline the importance of our method to improve understanding of gross neural interactions underlying cognitive processes.

  6. Mixed time integration methods for transient thermal analysis of structures

    NASA Technical Reports Server (NTRS)

    Liu, W. K.

    1982-01-01

    The computational methods used to predict and optimize the thermal structural behavior of aerospace vehicle structures are reviewed. In general, two classes of algorithms, implicit and explicit, are used in transient thermal analysis of structures. Each of these two methods has its own merits. Due to the different time scales of the mechanical and thermal responses, the selection of a time integration method can be a different yet critical factor in the efficient solution of such problems. Therefore mixed time integration methods for transient thermal analysis of structures are being developed. The computer implementation aspects and numerical evaluation of these mixed time implicit-explicit algorithms in thermal analysis of structures are presented. A computationally useful method of estimating the critical time step for linear quadrilateral element is also given. Numerical tests confirm the stability criterion and accuracy characteristics of the methods. The superiority of these mixed time methods to the fully implicit method or the fully explicit method is also demonstrated.

  7. Transient Region Coverage in the Propulsion IVHM Technology Experiment

    NASA Technical Reports Server (NTRS)

    Balaban, Edward; Sweet, Adam; Bajwa, Anupa; Maul, William; Fulton, Chris; Chicatelli, amy

    2004-01-01

    Over the last several years researchers at NASA Glenn and Ames Research Centers have developed a real-time fault detection and isolation system for propulsion subsystems of future space vehicles. The Propulsion IVHM Technology Experiment (PITEX), as it is called follows the model-based diagnostic methodology and employs Livingstone, developed at NASA Ames, as its reasoning engine. The system has been tested on,flight-like hardware through a series of nominal and fault scenarios. These scenarios have been developed using a highly detailed simulation of the X-34 flight demonstrator main propulsion system and include realistic failures involving valves, regulators, microswitches, and sensors. This paper focuses on one of the recent research and development efforts under PITEX - to provide more complete transient region coverage. It describes the development of the transient monitors, the corresponding modeling methodology, and the interface software responsible for coordinating the flow of information between the quantitative monitors and the qualitative, discrete representation Livingstone.

  8. Measurement of local high-level, transient surface heat flux

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.

    1988-01-01

    This study is part of a continuing investigation to develop methods for measuring local transient surface heat flux. A method is presented for simultaneous measurements of dual heat fluxes at a surface location by considering the heat flux as a separate function of heat stored and heat conducted within a heat flux gage. Surface heat flux information is obtained from transient temperature measurements taken at points within the gage. Heat flux was determined over a range of 4 to 22 MW/sq m. It was concluded that the method is feasible. Possible applications are for heat flux measurements on the turbine blade surfaces of space shuttle main engine turbopumps and on the component surfaces of rocket and advanced gas turbine engines and for testing sensors in heat flux gage calibrators.

  9. Phenomenological model for transient deformation based on state variables

    SciTech Connect

    Jackson, M S; Cho, C W; Alexopoulos, P; Mughrabi, H; Li, C Y

    1980-01-01

    The state variable theory of Hart, while providing a unified description of plasticity-dominated deformation, exhibits deficiencies when it is applied to transient deformation phenomena at stresses below yield. It appears that the description of stored anelastic strain is oversimplified. Consideration of a simple physical picture based on continuum dislocation pileups suggests that the neglect of weak barriers to dislocation motion is the source of these inadequacies. An appropriately modified description incorporating such barriers then allows the construction of a macroscopic model including transient effects. Although the flow relations for the microplastic element required in the new theory are not known, tentative assignments may be made for such functions. The model then exhibits qualitatively correct behavior when tensile, loading-unloading, reverse loading, and load relaxation tests are simulated. Experimental procedures are described for determining the unknown parameters and functions in the new model.

  10. Transients in a circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Baskakov, A. P.; Munts, V. A.; Pavlyuk, E. Yu.

    2013-11-01

    Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained.

  11. Tracking Steady Light Sources Amid Luminous Transients

    NASA Technical Reports Server (NTRS)

    Kissh, Frank; Fowski, Walter; Miklus, Kenneth; Abreu, Rene; Bolin, Kenneth; Flynn, David

    1994-01-01

    The Transient Event Rejection for Acquisition and Tracking (TERAT) algorithm governs operation of image-data-acquisition and -processing system. TERAT processes digitized image data to acquire (that is, identify) candidate steady source of light, validate candidate source, and track validated source, all in presence of real or apparent luminous transients represented in image data. Source of light tracked could be star or distant luminous beacon. Transients caused by impacts of ionizing radiation on imaging array of photodetectors or by unsteady light sources not meant to be tracked. TERAT functions with limited data-processing resources. TERAT algorithm currently operational on NASA's TOPEX mission.

  12. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

    Reagan, M. K.; Bowman, W. J.

    1993-01-01

    This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

  13. Fermi-LAT Observations of Galactic Transients

    NASA Technical Reports Server (NTRS)

    Hays, Elizabeth

    2011-01-01

    This slide presentation reviews the observations of Galactic transients by the Large Area Telescope (LAT) on the Fermi Gamma Ray Space Telescope. The LAT is producing spectacular results for the GeV transient sky, some of which are shown and reviewed. Some of the results in the GeV range that are discussed in this presentation are: (1) New blazars and unidentified transients (2) the jet of the Cygnus X-3 microquasar (3) gamma rays from V407 Cygni nova (4) Fast high-energy gamma-ray flares from the Crab Nebula

  14. Transient period process control for continuous manufacturing

    SciTech Connect

    Nembhard, H.B.; Birge, J.R.

    1994-12-31

    We develop a multiple objective nonlinear control model to optimize decision variables for correlated process characteristics during a transient phase. Given a continuous manufacturing process we show how to use the model to improve operations from startup to the end of the transient period (when steady-state is reached). We also show how to identify the end of the transient period and compare performance using the model during steady-state to traditional SPC techniques that assume the process is in statistical control.

  15. Transient aphasias after left hemisphere resective surgery

    PubMed Central

    Wilson, Stephen M.; Lam, Daniel; Babiak, Miranda; Perry, David; Shih, Tina; Hess, Christopher P.; Berger, Mitchel S.; Chang, Edward F.

    2015-01-01

    Object Transient aphasias are often observed in the first few days in patients who undergo surgical resection in the language-dominant hemisphere. The aims of this prospective study were to characterize the incidence and nature of these aphasias, and to determine whether there are relationships between location of the surgical site and deficits in specific language domains. Methods 110 patients undergoing resection to the language-dominant hemisphere participated in the study. Patients’ language was evaluated prior to surgery, 2-3 days post-surgery, and 1 month post-surgery using the Western Aphasia Battery and the Boston Naming Test. Voxel-based lesion-symptom mapping was used to identify relationships between the location of the surgical site assessed by MRI, and deficits in fluency, information content, comprehension, repetition, and naming. Results 71% of patients were classified as aphasic based on the Western Aphasia Battery 2-3 days post-surgery, with deficits observed in each of the language domains examined. Fluency deficits were associated with resection of the precentral gyrus and adjacent inferior frontal cortex. Reduced information content of spoken output was associated with resection of the ventral precentral gyrus and posterior inferior frontal gyrus (pars opercularis). Repetition deficits were associated with resection of the posterior superior temporal gyrus. Naming deficits were associated with resection of ventral temporal cortex, with mid temporal and posterior temporal damage more predictive of naming deficits than anterior temporal damage. By 1 month post-surgery, nearly all language deficits were resolved, and no language measure except for naming differed significantly from pre-surgical levels. Conclusions These findings show that transient aphasias are very common after left hemisphere resective surgery, and that the precise nature of the aphasia depends on the specific location of the surgical site. This patient cohort provides a unique

  16. Transient resonances in the inspirals

    NASA Astrophysics Data System (ADS)

    Hinderer, Tanja; Flanagan, Eanna

    2009-05-01

    We show that the two body problem in general relativity in the highly relativistic regime has a qualitatively new feature: the occurence of transient resonances. The resonances occur when the ratio of polar and radial orbital frequencies, which is slowly evolving under the influence of gravitational radiation reaction, passes through a low order rational number. The resonances make the orbit more sensitive to changes in the initial data (though not quite chaotic), and are genuine non-perturbative effects that are not seen at any order in the standard post-Newtonian expansion used for two body systems at large separation. Our results directly apply to an important potential source of gravitational waves, namely the gradual inspiral of compact objects into much more massive black holes. Exploiting observations of these gravitational waves to map the spacetime geometry of black holes is contingent upon accurate theoretical models (templates) of the binary dynamics. At present, only the leading order in the mass ratio gravitational waveforms can be computed. Corrections to the waveform's phase due to resonance effects scale as the square root of the inverse of the mass ratio and are characterized by sudden jumps in the time derivatives of the phase. We numerically estimate the net size of these corrections and find indications that the phase error is of order a few cycles for mass ratios ˜10^- 3 but will be significant (of order tens of cycles) for mass ratios ˜10-6. Computations of these corrections will require the computation of pieces of the forcing terms in the equations of motion which are currently unknown.

  17. MICA Observations of Coronal Transients

    NASA Astrophysics Data System (ADS)

    Stenborg, G.; Schwenn, R.; Srivastava, N.

    1999-10-01

    Dynamical processes are well known to occur in the inner solar atmosphere, many of them giving origin to spectacular eruptions known as coronal mass ejections. The projected velocity of propagation of these events ranges from less than 100 km/sec to greater than 1200 km/sec. In order to study the initial evolution of the faster processes it is necessary to image the inner corona at a very high cadence. Although ground-based observations of the corona are strongly affected by sky conditions they allow imaging at a high temporal resolution as compared to coronagraphic observations from space. In the recently inaugurated German-Argentinean Solar-Observatory at El Leoncito, San Juan, Argentina, a mirror coronagraph (MICA) daily images the inner solar corona with high temporal and spatial resolution in two spectral ranges: the well known green (~1.8 MK) and red (~1.0 MK) coronal lines at 5303 A and 6374 A respectively. It is essentially similar in design to LASCO-C1 on board SOHO, its field-of-view ranging from 1.05 to 2.0 solar radii from the sun center. Thus, it is ideally suited to observe the hot material and reveal the fast processes that occur in the coronal plasma. In the last year MICA has recorded several fast and not so fast green line transients at a high temporal resolution. In this work we will present observations of a few such events. This study would allow us to have a better understanding of the conditions that trigger the coronal mass ejections and their propagation in the inner solar corona.

  18. Transient platoon aerodynamics and bluff body flows

    NASA Astrophysics Data System (ADS)

    Tsuei, Lun

    There are two components of this experimental work: transient vehicle platoon aerodynamics and bluff-body flows. The transient aerodynamic effects in a four-vehicle platoon during passing maneuvers and in-line oscillations are investigated. A vehicle model is moved longitudinally parallel to a four-car platoon to simulate passing maneuvers. The drag and side forces experienced by each platoon member are measured using strain gauge balances. The resulting data are presented as dimensionless coefficients. It is shown that each car in the platoon experiences a repulsive side force when the passing vehicle is in the neighborhood of its rear half. The side force reverses its direction and becomes an attractive force when the passing vehicle moves to the neighborhood of its front half. The drag force experienced by each platoon member is increased when the passing vehicle is in its proximity. The effects of the lateral spacing and relative velocity between the platoon and the passing vehicle, as well as the shape of the passing vehicle, are also investigated. Similar trends are observed in simulations of both a vehicle passing a platoon and a platoon overtaking a vehicle. During the in-line oscillation experiments, one of the four platoon members is forced to undergo longitudinal periodic motions. The drag force experienced by each platoon member is determined simultaneously during the oscillations. The effects of the location of the oscillating vehicle, the shape of the vehicles and the displacement and velocity amplitudes of the oscillation are examined. The results from the transient conditions are compared to those from the steady tests in the same setup. In the case of a four-car platoon, the drag variations experienced by the vehicles adjacent to the oscillating vehicle are discussed using a cavity model. It is found that when the oscillating car moves forward and approaches its upstream neighbor, itself and its downstream neighbor experiences an increased drag

  19. Peach Bottom Turbine Trip Simulations with RETRAN Using INER/TPC BWR Transient Analysis Method

    SciTech Connect

    Kao Lainsu; Chiang, Show-Chyuan

    2005-03-15

    The work described in this paper is benchmark calculations of pressurization transient turbine trip tests performed at the Peach Bottom boiling water reactor (BWR). It is part of an overall effort in providing qualification basis for the INER/TPC BWR transient analysis method developed for the Kuosheng and Chinshan plants. The method primarily utilizes an advanced system thermal hydraulics code, RETRAN02/MOD5, for transient safety analyses. Since pressurization transients would result in a strong coupling effect between core neutronic and system thermal hydraulics responses, the INER/TPC method employs the one-dimensional kinetic model in RETRAN with a cross-section data library generated by the Studsvik-CMS code package for the transient calculations. The Peach Bottom Turbine Trip (PBTT) tests, including TT1, TT2, and TT3, have been successfully performed in the plant and assigned as standards commonly for licensing method qualifications for years. It is an essential requirement for licensing purposes to verify integral capabilities and accuracies of the codes and models of the INER/TPC method in simulating such pressurization transients. Specific Peach Bottom plant models, including both neutronics and thermal hydraulics, are developed using modeling approaches and experiences generally adopted in the INER/TPC method. Important model assumptions in RETRAN for the PBTT test simulations are described in this paper. Simulation calculations are performed with best-estimated initial and boundary conditions obtained from plant test measurements. The calculation results presented in this paper demonstrate that the INER/TPC method is capable of calculating accurately the core and system transient behaviors of the tests. Excellent agreement, both in trends and magnitudes between the RETRAN calculation results and the PBTT measurements, shows reliable qualifications of the codes/users/models involved in the method. The RETRAN calculated peak neutron fluxes of the PBTT

  20. Transient topographical amnesia: a case report.

    PubMed

    Mazzoni, M; Del Torto, E; Vista, M; Moretti, P

    1993-12-01

    We describe the case of a 56 year old female, with history of migraine since adolescence, who experienced two episodes of transient topographical disorientation in the absence of intellectual deterioration or evident focal cerebral lesions.

  1. Transient thermal analysis of fluid systems

    NASA Technical Reports Server (NTRS)

    Chandler, G. D.; Trust, R. D.

    1977-01-01

    Computer program performs transient thermal analysis of any 2-node to 200-node-thermal network, which transports heat by fluid flow convection. Program can be modified to add conduction along tubes and radiation.

  2. Transient Phenomena: Opportunities for New Discoveries

    NASA Technical Reports Server (NTRS)

    Lazio, T. Joseph W.

    2010-01-01

    Known classes of radio wavelength transients range from the nearby (stellar flares and radio pulsars) to the distant Universe (gamma-ray burst afterglows). Hypothesized classes of radio transients include analogs of known objects, such as extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies, to the exotic, such as prompt emission from gamma-ray bursts, evaporating black holes and transmitters from other civilizations. Time domain astronomy has been recognized internationally as a means of addressing key scientific questions in astronomy and physics, and pathfinders and Precursors to the Square Kilometre Array (SKA) are beginning to offer a combination of wider fields of view and more wavelength agility than has been possible in the past. These improvements will continue when the SKA itself becomes operational. I illustrate the range of transient phenomena and discuss how the detection and study of radio transients will improve immensely.

  3. Transient transfection of purified Babesia bovis merozoites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transient transfection of intraerythrocytic Babesia bovis parasites has been previously reported. In this study, we describe the development and optimization of methods for transfection of purified B. bovis merozoites using either nucleofection (Amaxa) or conventional electroporation (Gene Pulser II...

  4. Concurrent algorithms for transient FE analysis

    NASA Technical Reports Server (NTRS)

    Ortiz, M.; Nour-Omid, B.

    1989-01-01

    Information on concurrent algorithms for transient finite element analysis is given in viewgraph form. Information is given on concurrent dynamic algorithms, interprocessor communication, the performance of the BAR problem on the 32 Processor Hypercube, computational efficiency and accuracy analysis.

  5. Transient Evoked and Distortion Product Otoacoustic Emissions in a Group of Neonates

    PubMed Central

    Silva, Giovanna Cesar; Delecrode, Camila Ribas; Kemp, Adriana Tahara; Martins, Fabiana; Cardoso, Ana Claudia Vieira

    2015-01-01

    Introduction The most commonly used method in neonatal hearing screening programs is transient evoked otoacoustic emissions in the first stage of the process. There are few studies comparing transient evoked otoacoustic emissions with distortion product, but some authors have investigated the issue. Objective To correlate the results of transient evoked and distortion product otoacoustic emissions in a Brazilian maternity hospital. Methods This is a cross-sectional, comparative, and prospective study. The study included 579 newborns, ranging from 6 to 54 days of age, born in a low-risk maternity hospital and assessed for hearing loss. All neonates underwent hearing screening by transient evoked and distortion product otoacoustic emissions. The results were analyzed using the Spearman correlation test to relate the two procedures. Results The pass index on transient evoked otoacoustic emissions was 95% and on distortion product otoacoustic emissions was 91%. The comparison of the two procedures showed that 91% of neonates passed on both procedures, 4.5% passed only on transient evoked otoacoustic emissions, 0.5% passed only on distortion product otoacoustic emissions, and 4% failed on both procedures. The inferential analysis showed a significant strong positive relationship between the two procedures. Conclusion The failure rate was higher in distortion product otoacoustic emissions when compared with transient evoked; however, there was correlation between the results of the procedures. PMID:26157501

  6. Transient Evoked and Distortion Product Otoacoustic Emissions in a Group of Neonates.

    PubMed

    Silva, Giovanna Cesar; Delecrode, Camila Ribas; Kemp, Adriana Tahara; Martins, Fabiana; Cardoso, Ana Claudia Vieira

    2015-07-01

    Introduction The most commonly used method in neonatal hearing screening programs is transient evoked otoacoustic emissions in the first stage of the process. There are few studies comparing transient evoked otoacoustic emissions with distortion product, but some authors have investigated the issue. Objective To correlate the results of transient evoked and distortion product otoacoustic emissions in a Brazilian maternity hospital. Methods This is a cross-sectional, comparative, and prospective study. The study included 579 newborns, ranging from 6 to 54 days of age, born in a low-risk maternity hospital and assessed for hearing loss. All neonates underwent hearing screening by transient evoked and distortion product otoacoustic emissions. The results were analyzed using the Spearman correlation test to relate the two procedures. Results The pass index on transient evoked otoacoustic emissions was 95% and on distortion product otoacoustic emissions was 91%. The comparison of the two procedures showed that 91% of neonates passed on both procedures, 4.5% passed only on transient evoked otoacoustic emissions, 0.5% passed only on distortion product otoacoustic emissions, and 4% failed on both procedures. The inferential analysis showed a significant strong positive relationship between the two procedures. Conclusion The failure rate was higher in distortion product otoacoustic emissions when compared with transient evoked; however, there was correlation between the results of the procedures. PMID:26157501

  7. Detection of Radio Transients from Supernovae

    NASA Astrophysics Data System (ADS)

    Schmitt, Christian

    2011-05-01

    A core-collapse supernova (SN) would produce an expanding shell of charged particles which interact with the surrounding magnetic field of the progenitor star producing a transient radio pulse. Approximately one supernova event per century is expected in a galaxy. The radio waves emitted are detectable by a new generation of low-frequency radio telescope arrays. We present details of an ongoing search for such events by the Eight-meter-wavelength Transient Array (ETA) and the Long Wavelength Array (LWA).

  8. Transient ischemic attack presenting in an elderly patient with transient ophthalmic manifestations.

    PubMed

    Jain, Sparshi; Saxena, Tishu; Singh, Sweta; Singh, Nidhi

    2016-01-01

    Transient ischemic attack (TIA) is a transient neurological deficit of cerebrovascular origin without infarction which may last only for a short period and can have varying presentations. We report a case of 58-year-old male with presenting features of sudden onset transient vertical diplopia and transient rotatory nystagmus which self-resolved within 12 h. Patient had no history of any systemic illness. On investigating, hematological investigations and neuroimaging could not explain these sudden and transient findings. A TIA could possibly explain these sudden and transient ocular findings in our patient. This case report aims to highlight the importance of TIA for ophthalmologists. We must not ignore these findings as these could be warning signs of an impending stroke which may or may not be detected on neuroimaging. Thus, early recognition, primary prevention strategies, and timely intervention are needed.

  9. Heat pipe testing program test plan

    SciTech Connect

    Bienert, W.B.

    1980-03-14

    A test plan is given which describes the tests to be conducted on several typical solar receiver heat pipes. The hardware to be used, test fixtures and rationale of the test program are discussed. The program objective is to perform life testing under simulated receiver conditions, and to conduct performance tests with selected heat pipes to further map their performance, particularly with regard to their transient behavior. Performance requirements are defined. Test fixtures designed for the program are described in detail, and their capabilities for simulating the receiver conditions and their limitations are discussed. The heat pipe design is given. (LEW)

  10. Transient Receptor Potential Channel Polymorphisms Are Associated with the Somatosensory Function in Neuropathic Pain Patients

    PubMed Central

    Baron, Ralf; Maier, Christoph; Tölle, Thomas R.; Treede, Rolf-Detlef; Berthele, Achim; Faltraco, Frank; Flor, Herta; Gierthmühlen, Janne; Haenisch, Sierk; Huge, Volker; Magerl, Walter; Maihöfner, Christian; Richter, Helmut; Rolke, Roman; Scherens, Andrea; Üçeyler, Nurcan; Ufer, Mike; Wasner, Gunnar; Zhu, Jihong; Cascorbi, Ingolf

    2011-01-01

    Transient receptor potential channels are important mediators of thermal and mechanical stimuli and play an important role in neuropathic pain. The contribution of hereditary variants in the genes of transient receptor potential channels to neuropathic pain is unknown. We investigated the frequency of transient receptor potential ankyrin 1, transient receptor potential melastin 8 and transient receptor potential vanilloid 1 single nucleotide polymorphisms and their impact on somatosensory abnormalities in neuropathic pain patients. Within the German Research Network on Neuropathic Pain (Deutscher Forscbungsverbund Neuropathischer Schmerz) 371 neuropathic pain patients were phenotypically characterized using standardized quantitative sensory testing. Pyrosequencing was employed to determine a total of eleven single nucleotide polymorphisms in transient receptor potential channel genes of the neuropathic pain patients and a cohort of 253 German healthy volunteers. Associations of quantitative sensory testing parameters and single nucleotide polymorphisms between and within groups and subgroups, based on sensory phenotypes, were analyzed. Single nucleotide polymorphisms frequencies did not differ between both the cohorts. However, in neuropathic pain patients transient receptor potential ankyrin 1 710G>A (rs920829, E179K) was associated with the presence of paradoxical heat sensation (p = 0.03), and transient receptor potential vanilloid 1 1911A>G (rs8065080, I585V) with cold hypoalgesia (p = 0.0035). Two main subgroups characterized by preserved (1) and impaired (2) sensory function were identified. In subgroup 1 transient receptor potential vanilloid 1 1911A>G led to significantly less heat hyperalgesia, pinprick hyperalgesia and mechanical hypaesthesia (p = 0.006, p = 0.005 and p<0.001) and transient receptor potential vanilloid 1 1103C>G (rs222747, M315I) to cold hypaesthesia (p = 0.002), but there was absence of associations in subgroup 2. In

  11. An excitable gene regulatory circuit induces transient cellular differentiation

    NASA Astrophysics Data System (ADS)

    Süel, Gürol M.; Garcia-Ojalvo, Jordi; Liberman, Louisa M.; Elowitz, Michael B.

    2006-03-01

    Certain types of cellular differentiation are probabilistic and transient. In such systems individual cells can switch to an alternative state and, after some time, switch back again. In Bacillus subtilis, competence is an example of such a transiently differentiated state associated with the capability for DNA uptake from the environment. Individual genes and proteins underlying differentiation into the competent state have been identified, but it has been unclear how these genes interact dynamically in individual cells to control both spontaneous entry into competence and return to vegetative growth. Here we show that this behaviour can be understood in terms of excitability in the underlying genetic circuit. Using quantitative fluorescence time-lapse microscopy, we directly observed the activities of multiple circuit components simultaneously in individual cells, and analysed the resulting data in terms of a mathematical model. We find that an excitable core module containing positive and negative feedback loops can explain both entry into, and exit from, the competent state. We further tested this model by analysing initiation in sister cells, and by re-engineering the gene circuit to specifically block exit. Excitable dynamics driven by noise naturally generate stochastic and transient responses, thereby providing an ideal mechanism for competence regulation.

  12. FRINK - A Code to Evaluate Space Reactor Transients

    SciTech Connect

    Poston, David I.; Marcille, Thomas F.; Dixon, David D.; Amiri, Benjamin W.

    2007-01-30

    One of the biggest needs for space reactor design and development is detailed system modeling. Most proposed space fission systems are very different from previously operated fission power systems, and extensive testing and modeling will be required to demonstrate integrated system performance. There are also some aspects of space reactors that make them unique from most terrestrial application, and require different modeling approaches. The Fission Reactor Integrated Nuclear Kinetics (FRINK) code was developed to evaluate simplified space reactor transients (note: the term ''space reactor'' inherently includes planetary and lunar surface reactors). FRINK is an integrated point kinetic/thermal-hydraulic transient analysis FORTRAN code - ''integrated'' refers to the simultaneous solution of the thermal and neutronic equations. In its current state FRINK is a very simple system model, perhaps better referred to as a reactor model. The ''system'' only extends to the primary loop power removal boundary condition; however this allows the simulation of simplified transients (e.g. loss of primary heat sink, loss of flow, large reactivity insertion, etc.), which are most important in bounding early system conceptual design. FRINK could then be added to a complete system model later in the design and development process as system design matures.

  13. Transient Storage Parameterization of Wetland-dominated Stream Reaches

    NASA Astrophysics Data System (ADS)

    Wilderotter, S. M.; Lightbody, A.; Kalnejais, L. H.; Wollheim, W. M.

    2014-12-01

    Current understanding of the importance of transient storage in fluvial wetlands is limited. Wetlands that have higher connectivity to the main stream channel are important because they have the potential to retain more nitrogen within the river system than wetlands that receive little direct stream discharge. In this study, we investigated how stream water accesses adjacent fluvial wetlands in New England coastal watersheds to improve parameterization in network-scale models. Break through curves of Rhodamine WT were collected for eight wetlands in the Ipswich and Parker (MA) and Lamprey River (NH) watersheds, USA. The curves were inverse modeled using STAMMT-L to optimize the connectivity and size parameters for each reach. Two approaches were tested, a single dominant storage zone and a range of storage zones represented using a power-law distribution of storage zone connectivity. Multiple linear regression analyses were conducted to relate transient storage parameters to stream discharge, area, length-to-width ratio, and reach slope. Resulting regressions will enable more accurate parameterization of surface water transient storage in network-scale models.

  14. Fission product transport and behavior during two postulated loss of flow transients in the air

    SciTech Connect

    Adams, J.P.; Carboneau, M.L.

    1991-12-31

    This document discusses fission product behavior during two postulated loss-of-flow accidents (leading to high- and low-pressure core degradation, respectively) in the Advanced Test Reactor (ATR). These transients are designated ATR Transient LCPI5 (high-pressure) and LPP9 (low-pressure). Normally, transients of this nature would be easily mitigated using existing safety systems and procedures. In these analyses, failure of these safety systems was assumed so that core degradation and fission product release could be analyzed. A probabilistic risk assessment indicated that the probability of occurrence for these two transients is of the order of 10{sup {minus}5 }and 10{sup {minus}7} per reactor year for LCP15 and LPP9, respectively.

  15. Fission product transport and behavior during two postulated loss of flow transients in the air

    SciTech Connect

    Adams, J.P.; Carboneau, M.L.

    1991-01-01

    This document discusses fission product behavior during two postulated loss-of-flow accidents (leading to high- and low-pressure core degradation, respectively) in the Advanced Test Reactor (ATR). These transients are designated ATR Transient LCPI5 (high-pressure) and LPP9 (low-pressure). Normally, transients of this nature would be easily mitigated using existing safety systems and procedures. In these analyses, failure of these safety systems was assumed so that core degradation and fission product release could be analyzed. A probabilistic risk assessment indicated that the probability of occurrence for these two transients is of the order of 10{sup {minus}5 }and 10{sup {minus}7} per reactor year for LCP15 and LPP9, respectively.

  16. Model Fidelity Study of Dynamic Transient Loads in a Wind Turbine Gearbox: Preprint

    SciTech Connect

    Guo, Y.; Keller, J.; Moan, T.; Xing, Y.

    2013-04-01

    Transient events cause high loads in the drivetrain components so measuring and calculating these loads can improve confidence in drivetrain design. This paper studies the Gearbox Reliability Collaborative 750kW wind turbine gearbox response during transient events using a combined experimental and modeling approach. The transient events include emergency shut-downs and start-ups measured during a field testing period in 2009. The drivetrain model is established in the multibody simulation tool Simpack. A detailed study of modeling fidelity required for accurate load prediction is performed and results are compared against measured loads. A high fidelity model that includes shaft and housing flexibility and accurate bearing stiffnesses is important for the higher-speed stage bearing loads. Each of the transient events has different modeling requirements.

  17. The agile alert system for gamma-ray transients

    SciTech Connect

    Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Fioretti, V.; Chen, A. W.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Santolamazza, P.; Fanari, G.; Giommi, P.; Pellizzoni, A.; and others

    2014-01-20

    In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.

  18. Multiple-Beam Detection of Fast Transient Radio Sources

    NASA Technical Reports Server (NTRS)

    Thompson, David R.; Wagstaff, Kiri L.; Majid, Walid A.

    2011-01-01

    A method has been designed for using multiple independent stations to discriminate fast transient radio sources from local anomalies, such as antenna noise or radio frequency interference (RFI). This can improve the sensitivity of incoherent detection for geographically separated stations such as the very long baseline array (VLBA), the future square kilometer array (SKA), or any other coincident observations by multiple separated receivers. The transients are short, broadband pulses of radio energy, often just a few milliseconds long, emitted by a variety of exotic astronomical phenomena. They generally represent rare, high-energy events making them of great scientific value. For RFI-robust adaptive detection of transients, using multiple stations, a family of algorithms has been developed. The technique exploits the fact that the separated stations constitute statistically independent samples of the target. This can be used to adaptively ignore RFI events for superior sensitivity. If the antenna signals are independent and identically distributed (IID), then RFI events are simply outlier data points that can be removed through robust estimation such as a trimmed or Winsorized estimator. The alternative "trimmed" estimator is considered, which excises the strongest n signals from the list of short-beamed intensities. Because local RFI is independent at each antenna, this interference is unlikely to occur at many antennas on the same step. Trimming the strongest signals provides robustness to RFI that can theoretically outperform even the detection performance of the same number of antennas at a single site. This algorithm requires sorting the signals at each time step and dispersion measure, an operation that is computationally tractable for existing array sizes. An alternative uses the various stations to form an ensemble estimate of the conditional density function (CDF) evaluated at each time step. Both methods outperform standard detection strategies on a test

  19. The AGILE Alert System for Gamma-Ray Transients

    NASA Astrophysics Data System (ADS)

    Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Tavani, M.; Parmiggiani, N.; Fioretti, V.; Chen, A. W.; Vercellone, S.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Santolamazza, P.; Fanari, G.; Giommi, P.; Beneventano, D.; Argan, A.; Trois, A.; Scalise, E.; Longo, F.; Pellizzoni, A.; Pucella, G.; Colafrancesco, S.; Conforti, V.; Tempesta, P.; Cerone, M.; Sabatini, P.; Annoni, G.; Valentini, G.; Salotti, L.

    2014-01-01

    In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.

  20. Transient Cognitive Dynamics, Metastability, and Decision Making

    PubMed Central

    Rabinovich, Mikhail I.; Huerta, Ramón; Varona, Pablo; Afraimovich, Valentin S.

    2008-01-01

    The idea that cognitive activity can be understood using nonlinear dynamics has been intensively discussed at length for the last 15 years. One of the popular points of view is that metastable states play a key role in the execution of cognitive functions. Experimental and modeling studies suggest that most of these functions are the result of transient activity of large-scale brain networks in the presence of noise. Such transients may consist of a sequential switching between different metastable cognitive states. The main problem faced when using dynamical theory to describe transient cognitive processes is the fundamental contradiction between reproducibility and flexibility of transient behavior. In this paper, we propose a theoretical description of transient cognitive dynamics based on the interaction of functionally dependent metastable cognitive states. The mathematical image of such transient activity is a stable heteroclinic channel, i.e., a set of trajectories in the vicinity of a heteroclinic skeleton that consists of saddles and unstable separatrices that connect their surroundings. We suggest a basic mathematical model, a strongly dissipative dynamical system, and formulate the conditions for the robustness and reproducibility of cognitive transients that satisfy the competing requirements for stability and flexibility. Based on this approach, we describe here an effective solution for the problem of sequential decision making, represented as a fixed time game: a player takes sequential actions in a changing noisy environment so as to maximize a cumulative reward. As we predict and verify in computer simulations, noise plays an important role in optimizing the gain. PMID:18452000

  1. Four RNA families with functional transient structures

    PubMed Central

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5′ flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5′ UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM

  2. Four RNA families with functional transient structures.

    PubMed

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5' flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5' UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All

  3. Transient natural convection in heated inclined tubes

    SciTech Connect

    McEligot, D.M. . Oceanic Div.); Denbow, D.A. ); Murphy, H.D. )

    1990-05-01

    To simulate natural convection flow patterns in directionally drilled wellbores, experiments and analyses were conducted for a circular tube with length-to-diameter (L/D) ratio of 36 at angles of 0{degree}, 20{degree}, and 35{degree} from the vertical. The tube was heated at the bottom and cooled at the top, and the insulation was adjusted so that approximately one- to two-thirds of the power dissipated was transferred through the tube wall to the surroundings. An aqueous solution of polyvinyl alcohol was employed as the working fluid in order to obtain low Rayleigh numbers corresponding to conditions in geothermal wellbores. Results were primarily qualitative but were useful in providing insight into the phenomena occurring. Steady-state temperature distributions were measured for the three orientations and for several heating rates to demonstrate the effects of tube angle and Rayleigh number. transient measurements of the temperature distribution were obtained during cooling from a higher temperature without a heat source to calibrate the heat losses. With the electrical heat source, temporal data were taken during heating to examine the approach to steady state. Quasi-steady flow conditions were approached rapidly, but the overall time constant of the apparatus was of the order of one-third of a day. Predictions with the three-dimensional TEMPEST code were first tested by comparison with simple conduction analyses. Comparison with actual data showed good agreement of the predicted temperature levels for the maximum inclination, 35{degree}, and slightly poorer agreement for the other limit, a vertical tube. Trends of temperature level and Nusselt number with heating rate or Rayleigh number were reasonable, but the predicted variation of the end Nusselt number versus inclination was in the opposite direction from the experiment. 75 refs., 20 figs., 8 tabs.

  4. Novel application-oriented transient fuel model of a port fuel injection S. I. engine

    NASA Astrophysics Data System (ADS)

    Wang, Cunlei; Zhang, Jianlong; Yin, Chengliang

    2014-03-01

    Most researches on transient fuel control of port fuel injection S.I. engine are carried out from the perspective of advanced mathematical theories. When it comes to practical control, there exist many limitations although they are more intelligent. In order to overcome the fuel wetting effect of PFI engine, the application-oriented transient fuel control is studied by analyzing the key parameters which are closely related with the engine transient characteristics. Both validity and simplicity are taken into consideration. Based on the fuel wall-wetting theory and popular fuel compensation strategy, short-term transient fuel(STF) and long-term transient fuel(LTF), as well as their individual decay approaches, are introduced. STF is to compensate the drastic fuel film loss caused by sudden throttle change, while the function of LTF is to compensate the fuel film loss by manifold air pressure( p) fluctuation. Each of them has their respective pros and cons. The engine fuel mass and air mass are also calculated for air-fuel ratio(AFR) according to ideal gas state equation and empirical equations. The vehicle acceleration test is designed for model validation. The engine experiences several mild and heavy accelerations corresponding to the gear change during vehicle acceleration. STF and LTF control are triggered reliably. The engine transient fuel control simulation adopts the same inputs as the test to ensure consistency. The logged test data are used to check the model output. The results show that the maximum fuel pulse width(FPW) error reaches 2 ms, and it only occurs under engine heavy acceleration condition. The average FPW error is 0.57 ms. The results of simulation and test are close overall, which indicates the accuracy of steady and transient fuel. The proposed research provides an efficient approach not only suitable for practical engineering application, but also for AFR prediction, fuel consumption calculation, and further studies on emission control.

  5. Transient simulation of molten salt central receiver

    NASA Astrophysics Data System (ADS)

    Doupis, Dimitri; Wang, Chuan; Carcorze-Soto, Jorge; Chen, Yen-Ming; Maggi, Andrea; Losito, Matteo; Clark, Michael

    2016-05-01

    Alstom is developing concentrated solar power (CSP) utilizing 60/40wt% NaNO3-KNO3 molten salt as the working fluid in a tower receiver for the global renewable energy market. In the CSP power generation cycle, receivers undergo a daily cyclic operation due to the transient nature of solar energy. Development of robust and efficient start-up and shut-down procedures is critical to avoiding component failures due to mechanical fatigue resulting from thermal transients, thus maintaining the performance and availability of the CSP plant. The Molten Salt Central Receiver (MSCR) is subject to thermal transients during normal daily operation, a cycle that includes warmup, filling, operation, draining, and shutdown. This paper describes a study to leverage dynamic simulation and finite element analysis (FEA) in development of start-up, shutdown, and transient operation concepts for the MSCR. The results of the FEA also verify the robustness of the MSCR design to the thermal transients anticipated during the operation of the plant.

  6. Transient particle emission measurement with optical techniques

    NASA Astrophysics Data System (ADS)

    Bermúdez, Vicente; Luján, José M.; Serrano, José R.; Pla, Benjamín

    2008-06-01

    Particulate matter is responsible for some respiratory and cardiovascular diseases. In addition, it is one of the most important pollutants of high-speed direct injection (HSDI) passenger car engines. Current legislation requires particulate dilution tunnels for particulate matter measuring. However for development work, dilution tunnels are expensive and sometimes not useful since they are not able to quantify real-time particulate emissions during transient operation. In this study, the use of a continuous measurement opacimeter and a fast response HFID is proven to be a good alternative to obtain instantaneous particle mass emissions during transient operation (due to particulate matter consisting mainly of soot and SOF). Some methods and correlations available from literature, but developed for steady conditions, are evaluated during transient operation by comparing with mini-tunnel measurements during the entire MVEG-A transient cycle. A new correlation was also derived from this evaluation. Results for soot and SOF (obtained from the new correlation proposed) are compared with soot and SOF captured with particulate filters, which have been separated by means of an SOF extraction method. Finally, as an example of ECU design strategies using these sort of correlations, the EGR valve opening is optimized during transient operation. The optimization is performed while simultaneously taking into account instantaneous fuel consumption, particulate emissions (calculated with the proposed correlation) and other regulated engine pollutants.

  7. Laser-induced stress transients: aqueous pores of membranes

    NASA Astrophysics Data System (ADS)

    Flotte, Thomas J.; Lee, Shun; Zhang, Hong; McAuliffe, Daniel J., Sr.; Taitelbaum, Jeremy; Doukas, Apostolos G.

    1996-05-01

    Lasers can be used to enhance the delivery of a number of molecules. The model that best fits our data is for the formation of aqueous pores. These pores are present for up to 80 seconds. Our experiments have shown that laser-induced stress transients can be utilized as a vector for intracellular delivery of molecules that may or may not normally cross the cell membrane. These two conditions have been tested with Photofrin and DNA. This technology may have applications in cell and molecular biology, cancer therapy, gene therapy, and others.

  8. Development of the Burst and Transient Source Experiment (BATSE)

    NASA Technical Reports Server (NTRS)

    Horack, J. M.

    1991-01-01

    The Burst and Transient Source Experiment (BATSE), one of four instruments on the Gamma Ray Observatory, consists of eight identical detector modules mounted on the corners of the spacecraft. Developed at MSFC, BATSE is the most sensitive gamma ray burst detector flown to date. Details of the assembly and test phase of the flight hardware development are presented. Results and descriptions of calibrations performed at MSFC, TRW, and KSC are documented extensively. With the presentation of each calibration results, the reader is provided with the means to access raw calibration data for further review or analysis.

  9. Transient sinus node dysfunction with acute hepatitis of unknown etiology.

    PubMed

    Al-Fagih, Ahmed R; Al-Ghamdi, Saleh A; Dagriri, Khaled G; Al-Malki, Ahmed S

    2010-05-01

    We reported a case of a 72-year-old male, known diabetic on insulin, referred because of complete atrioventricular block. He was found to have acute hepatitis during which he developed transient atrial arrhythmia, and sinus node dysfunction. His cardiac symptoms disappeared completely after hepatitis improvement. All of his cardiac investigations were normal including electrocardiogram, echocardiography and thalium stress test. At 3 and 6 months follow up, his Holter monitoring did not show any further arrhythmia, and he denied any further episodes of palpitation or pre-syncope. We reviewed the literature regarding the relationship between hepatitis and atrial arrhythmia. PMID:20464052

  10. Transient thermal analysis as measurement method for IC package structural integrity

    NASA Astrophysics Data System (ADS)

    Hanß, Alexander; Schmid, Maximilian; Liu, E.; Elger, Gordon

    2015-06-01

    Practices of IC package reliability testing are reviewed briefly, and the application of transient thermal analysis is examined in great depth. For the design of light sources based on light emitting diode (LED) efficient and accurate reliability testing is required to realize the potential lifetimes of 105 h. Transient thermal analysis is a standard method to determine the transient thermal impedance of semiconductor devices, e.g. power electronics and LEDs. The temperature of the semiconductor junctions is assessed by time-resolved measurement of their forward voltage (Vf). The thermal path in the IC package is resolved by the transient technique in the time domain. This enables analyzing the structural integrity of the semiconductor package. However, to evaluate thermal resistance, one must also measure the dissipated energy of the device (i.e., the thermal load) and the k-factor. This is time consuming, and measurement errors reduce the accuracy. To overcome these limitations, an innovative approach, the relative thermal resistance method, was developed to reduce the measurement effort, increase accuracy and enable automatic data evaluation. This new way of evaluating data simplifies the thermal transient analysis by eliminating measurement of the k-factor and thermal load, i.e. measurement of the lumen flux for LEDs, by normalizing the transient Vf data. This is especially advantageous for reliability testing where changes in the thermal path, like cracks and delaminations, can be determined without measuring the k-factor and thermal load. Different failure modes can be separated in the time domain. The sensitivity of the method is demonstrated by its application to high-power white InGaN LEDs. For detailed analysis and identification of the failure mode of the LED packages, the transient signals are simulated by time-resolved finite element (FE) simulations. Using the new approach, the transient thermal analysis is enhanced to a powerful tool for reliability

  11. Transient Landscapes: Recorders of History and Engines of Discovery (Invited)

    NASA Astrophysics Data System (ADS)

    Whipple, K. X.

    2010-12-01

    picture. Transients acting over timescales ranging from ~10 kyr to ~10 Myr have been studied in recent years. Field observations and theoretical analyses, however, reveal complications that produce sometimes significant deviations from the simple model of a discrete change in channel steepness at an abrupt knickpoint. Knickpoints can be “leaky”, with landscape response in fact zipping ahead of the main knickpoint in many if not most cases. Initially transport-limited conditions, stripping of alluvial armor upstream of knickpoints, and erosional response to flow acceleration over waterfalls all contribute to landscape response upstream of major knickpoints. Downstream of knickpoints steepening of channel profiles occurs ahead of commensurate increases in the sediment load carried by streams. Accordingly, channels can become tool-starved and may respond by over-steepening, narrowing, and develop discrete bedrock steps and waterfalls. In extreme cases (very rapid incision) tributary streams may not be able to keep pace with the trunk stream and fluvial hanging valleys can develop, delaying tributary response and extending the duration of transients. These characteristics, among others, make transient landscapes excellent natural laboratories for testing and refining landscape evolution models in addition to their capacity to inform us about past conditions.

  12. Space Environmental Testing at GSFC

    NASA Technical Reports Server (NTRS)

    Kauder, Lonny R.

    2009-01-01

    This paper presents an overview of space environmental testing at NASA Goddard Space Flight Center. The contents include: 1) Solar Absorptance measurements; 2) Emittance measurements; 3) Transient Calorimetric Technique; 4) Electrostatic charge testing; 5) UV degradation testing; 6) Solar Wind Facility; and 7) Solar Wind testing.

  13. A Quantitative Study of the Characteristics of Transient and Non-Transient Students in Nevada Elementary Schools

    ERIC Educational Resources Information Center

    Parr, Andrew Joseph

    2010-01-01

    The purpose of this research was to determine whether transient or mobile students attain lower levels of academic achievement than non-transient students and to identify the characteristics distinguishing transient from non-transient students. The study analyzed the assessment results, student characteristics, and school factors for approximately…

  14. Chemotaxis Control of Transient Cell Aggregation

    PubMed Central

    2015-01-01

    Chemotaxis affords motile cells the ability to rapidly respond to environmental challenges by navigating cells to niches favoring growth. Such a property results from the activities of dedicated signal transduction systems on the motility apparatus, such as flagella, type IV pili, and gliding machineries. Once cells have reached a niche with favorable conditions, they often stop moving and aggregate into complex communities termed biofilms. An intermediate and reversible stage that precedes commitment to permanent adhesion often includes transient cell-cell contacts between motile cells. Chemotaxis signaling has been implicated in modulating the transient aggregation of motile cells. Evidence further indicates that chemotaxis-dependent transient cell aggregation events are behavioral responses to changes in metabolic cues that temporarily prohibit permanent attachment by maintaining motility and chemotaxis. This minireview discusses a few examples illustrating the role of chemotaxis signaling in the initiation of cell-cell contacts in bacteria moving via flagella, pili, or gliding. PMID:26216846

  15. Chemotaxis Control of Transient Cell Aggregation.

    PubMed

    Alexandre, Gladys

    2015-10-01

    Chemotaxis affords motile cells the ability to rapidly respond to environmental challenges by navigating cells to niches favoring growth. Such a property results from the activities of dedicated signal transduction systems on the motility apparatus, such as flagella, type IV pili, and gliding machineries. Once cells have reached a niche with favorable conditions, they often stop moving and aggregate into complex communities termed biofilms. An intermediate and reversible stage that precedes commitment to permanent adhesion often includes transient cell-cell contacts between motile cells. Chemotaxis signaling has been implicated in modulating the transient aggregation of motile cells. Evidence further indicates that chemotaxis-dependent transient cell aggregation events are behavioral responses to changes in metabolic cues that temporarily prohibit permanent attachment by maintaining motility and chemotaxis. This minireview discusses a few examples illustrating the role of chemotaxis signaling in the initiation of cell-cell contacts in bacteria moving via flagella, pili, or gliding.

  16. WIDGET: Ultra Bright Optical Transients Search

    NASA Astrophysics Data System (ADS)

    Urata, Y.; Lin, H.-M.; Tashiro, M.; Widget Team

    2010-12-01

    The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for a fully automated, ultra-wide-field survey aimed at detecting the prompt optical emission associated with Gamma-ray Bursts (GRB). WIDGET surveys the HETE-2 and Swift/BAT pointing directions covering a total field of view of 62x62 degree every 10 seconds using an unfiltered system. This monitoring survey allows exploration of the optical emission before the gamma-ray trigger. At the same time, WIDGET is the quite unique instrument to explore ultra-bright optical transients with high time resolution. Combination with the MAXI survey, WIDGET has higher potential to make simultaneous discoveries of optical counterparts for high energy transients. We developed the serendipitous transient finding pipeline. We report the preliminary results.

  17. Transient expression technologies: past, present, and future.

    PubMed

    Geisse, Sabine; Voedisch, Bernd

    2012-01-01

    The first protocols describing transient gene expression in mammalian cells for the rapid generation of recombinant proteins emerged more than 10 years ago as an alternative to the establishment of stable, often amplified clonal cell lines, and relieved somewhat the bias against mammalian cell systems as being too complicated, labor intensive, and tedious to serve as a source for tool proteins in industrial research and academia. Over the past decade, these attempts have been refined and optimized, giving rise to expression protocols applicable in every lab in dependence on available tools, equipment, and envisaged outcome. This chapter summarizes the development of transient expression technologies over the past decade up to its current status and provides an outlook into what may be the future of transient technology development.

  18. Transient misfolding dominates multidomain protein folding

    PubMed Central

    Borgia, Alessandro; Kemplen, Katherine R.; Borgia, Madeleine B.; Soranno, Andrea; Shammas, Sarah; Wunderlich, Bengt; Nettels, Daniel; Best, Robert B.; Clarke, Jane; Schuler, Benjamin

    2015-01-01

    Neighbouring domains of multidomain proteins with homologous tandem repeats have divergent sequences, probably as a result of evolutionary pressure to avoid misfolding and aggregation, particularly at the high cellular protein concentrations. Here we combine microfluidic-mixing single-molecule kinetics, ensemble experiments and molecular simulations to investigate how misfolding between the immunoglobulin-like domains of titin is prevented. Surprisingly, we find that during refolding of tandem repeats, independent of sequence identity, more than half of all molecules transiently form a wide range of misfolded conformations. Simulations suggest that a large fraction of these misfolds resemble an intramolecular amyloid-like state reported in computational studies. However, for naturally occurring neighbours with low sequence identity, these transient misfolds disappear much more rapidly than for identical neighbours. We thus propose that evolutionary sequence divergence between domains is required to suppress the population of long-lived, potentially harmful misfolded states, whereas large populations of transient misfolded states appear to be tolerated. PMID:26572969

  19. Earthquake triggering by transient and static deformations

    USGS Publications Warehouse

    Gomberg, J.; Beeler, N.M.; Blanpied, M.L.; Bodin, P.

    1998-01-01

    Observational evidence for both static and transient near-field and far-field triggered seismicity are explained in terms of a frictional instability model, based on a single degree of freedom spring-slider system and rate- and state-dependent frictional constitutive equations. In this study a triggered earthquake is one whose failure time has been advanced by ??t (clock advance) due to a stress perturbation. Triggering stress perturbations considered include square-wave transients and step functions, analogous to seismic waves and coseismic static stress changes, respectively. Perturbations are superimposed on a constant background stressing rate which represents the tectonic stressing rate. The normal stress is assumed to be constant. Approximate, closed-form solutions of the rate-and-state equations are derived for these triggering and background loads, building on the work of Dieterich [1992, 1994]. These solutions can be used to simulate the effects of static and transient stresses as a function of amplitude, onset time t0, and in the case of square waves, duration. The accuracies of the approximate closed-form solutions are also evaluated with respect to the full numerical solution and t0. The approximate solutions underpredict the full solutions, although the difference decreases as t0, approaches the end of the earthquake cycle. The relationship between ??t and t0 differs for transient and static loads: a static stress step imposed late in the cycle causes less clock advance than an equal step imposed earlier, whereas a later applied transient causes greater clock advance than an equal one imposed earlier. For equal ??t, transient amplitudes must be greater than static loads by factors of several tens to hundreds depending on t0. We show that the rate-and-state model requires that the total slip at failure is a constant, regardless of the loading history. Thus a static load applied early in the cycle, or a transient applied at any time, reduces the stress

  20. A CCD integrated circuit for transient recorders

    NASA Technical Reports Server (NTRS)

    Balch, J. W.; Mcconaghy, C. F.

    1976-01-01

    A 50 MHz CCD integrated circuit is described that was developed for use in transient analog signal recorders to sample and time expand transient signals. The integrated circuit achieves an effective 200 MHz sample rate by using four 32 stage peristaltic CCDs to sample the transient signal four times each clock period. Dual frequency, 4 phi clocking is used to sample and time expand the sampled data. The output signals of the four CCDs are multiplexed on chip into a single low frequency output data line. When operated with 50 MHz/165 KHz 4 phi clocks, this circuit has a 200 MHz sample rate, a record length of 640 nanoseconds, a time expansion factor of 303, and overall signal to noise ratio of 40:1. The signal to noise ratio is limited by fixed pattern noise of the four CCDs.

  1. Numerical simulation of transient hypervelocity flow in an expansion tube

    NASA Technical Reports Server (NTRS)

    Jacobs, P. A.

    1992-01-01

    Several numerical simulations of the transient flow of helium in an expansion tube are presented in an effort to identify some of the basic mechanisms which cause the noisy test flows seen in experiments. The calculations were performed with an axisymmetric Navier-Stokes code based on a finite volume formulation and upwinding techniques. Although laminar flow and ideal bursting of the diaphragms was assumed, the simulations showed some of the important features seen in experiments. In particular, the discontinuity in tube diameter of the primary diaphragm station introduced a transverse perturbation to the expanding driver gas and this perturbation was seen to propagate into the test gas under some flow conditions. The disturbances seen in the test flow can be characterized as either small amplitude, low frequency noise possibly introduced during shock compression or large amplitude, high frequency noise associated with the passage of the reflected head of the unsteady expansion.

  2. Investigation of natural circulation instability and transients in passively safe novel modular reactor

    NASA Astrophysics Data System (ADS)

    Shi, Shanbin

    The Purdue Novel Modular Reactor (NMR) is a new type small modular reactor (SMR) that belongs to the design of boiling water reactor (BWR). Specifically, the NMR is one third the height and area of a conventional BWR reactor pressure vessel (RPV) with an electric output of 50 MWe. The fuel cycle length of the NMR-50 is extended up to 10 years due to optimized neutronics design. The NMR-50 is designed with double passive engineering safety system. However, natural circulation BWRs (NCBWR) could experience certain operational difficulties due to flow instabilities that occur at low pressure and low power conditions. Static instabilities (i.e. flow excursion (Ledinegg) instability and flow pattern transition instability) and dynamic instabilities (i.e. density wave instability and flashing/condensation instability) pose a significant challenge in two-phase natural circulation systems. In order to experimentally study the natural circulation flow instability, a proper scaling methodology is needed to build a reduced-size test facility. The scaling analysis of the NMR uses a three-level scaling method, which was developed and applied for the design of the Purdue Multi-dimensional Integral Test Assembly (PUMA). Scaling criteria is derived from dimensionless field equations and constitutive equations. The scaling process is validated by the RELAP5 analysis for both steady state and startup transients. A new well-scaled natural circulation test facility is designed and constructed based on the scaling analysis of the NMR-50. The experimental facility is installed with different equipment to measure various thermal-hydraulic parameters such as pressure, temperature, mass flow rate and void fraction. Characterization tests are performed before the startup transient tests and quasi-steady tests to determine the loop flow resistance. The controlling system and data acquisition system are programmed with LabVIEW to realize the real-time control and data storage. The thermal

  3. Transient thermal camouflage and heat signature control

    NASA Astrophysics Data System (ADS)

    Yang, Tian-Zhi; Su, Yishu; Xu, Weikai; Yang, Xiao-Dong

    2016-09-01

    Thermal metamaterials have been proposed to manipulate heat flux as a new way to cloak or camouflage objects in the infrared world. To date, however, thermal metamaterials only operate in the steady-state and exhibit detectable, transient heat signatures. In this letter, the theoretical basis for a thermal camouflaging technique with controlled transient diffusion is presented. This technique renders an object invisible in real time. More importantly, the thermal camouflaging device instantaneously generates a pre-designed heat signature and behaves as a perfect thermal illusion device. A metamaterial coating with homogeneous and isotropic thermal conductivity, density, and volumetric heat capacity was fabricated and very good camouflaging performance was achieved.

  4. Transient astronomy with the Gaia satellite.

    PubMed

    Hodgkin, Simon T; Wyrzykowski, Łukasz; Blagorodnova, Nadejda; Koposov, Sergey

    2013-06-13

    Gaia is a cornerstone European Space Agency astrometry space mission and a successor to the Hipparcos mission. Gaia will observe the whole sky for 5 years, providing a serendipitous opportunity for the discovery of large numbers of transient and anomalous events, e.g. supernovae, novae and microlensing events, gamma-ray burst afterglows, fallback supernovae, as well as theoretical or unexpected phenomena. In this paper, we discuss our preparations to use Gaia to search for transients at optical wavelengths, and briefly describe the early detection, classification and prompt publication of anomalous sources. PMID:23630374

  5. Transient Rayleigh scattering from single semiconductor nanowires

    SciTech Connect

    Montazeri, Mohammad; Jackson, Howard E.; Smith, Leigh M.; Yarrison-Rice, Jan M.; Kang, Jung-Hyun; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati

    2013-12-04

    Transient Rayleigh scattering spectroscopy is a new pump-probe technique to study the dynamics and cooling of photo-excited carriers in single semiconductor nanowires. By studying the evolution of the transient Rayleigh spectrum in time after excitation, one can measure the time evolution of the density and temperature of photo-excited electron-hole plasma (EHP) as they equilibrate with lattice. This provides detailed information of dynamics and cooling of carriers including linear and bimolecular recombination properties, carrier transport characteristics, and the energy-loss rate of hot electron-hole plasma through the emission of LO and acoustic phonons.

  6. Modeling system for conducted transient analysis

    SciTech Connect

    Mahoney, T.L.

    1983-01-01

    A computer simulation system has been developed which facilitates the analysis of electrical/electronic systems. Sponsored by the Naval Air Systems Command to investigate power interface transient problems, the program is called the Navy Power Systems Simulator. The simulator is used as a system engineering tool which generates and processes models of virtually any electrical network. It is simple to use and capable of automatically producing a complex system's steady state or transient output response. An engineering friendly computer interface has been achieved by the extensive use of interactive graphics and menu-driven prompting.

  7. Iterative phase retrieval strategy of transient events.

    PubMed

    Ng, Tuck Wah; Chua, Adrian Sau Ling

    2012-01-20

    Important nuances of a process or processes in action can be obtained from the phase retrieval of diffraction patterns for analysis of transient events. A significant limitation associated with the iterative approach is that predictive input functions are needed and can result in situations of nonconvergence. In dealing with a transient event recorded as a series of Fourier magnitude patterns, such a hit-and-miss characteristic, on the surface, appears computationally daunting. We report and demonstrate a strategy here that effectively minimizes this by using a prior retrieved frame as the predictive function for the current retrieval process. PMID:22270666

  8. Experimental verification of transient nonlinear acoustical holography.

    PubMed

    Jing, Yun; Cannata, Jonathan; Wang, Tianren

    2013-05-01

    This paper presents an experimental study on nonlinear transient acoustical holography. The validity and effectiveness of a recently proposed nonlinear transient acoustical holography algorithm is evaluated in the presence of noise. The acoustic field measured on a post-focal plane of a high-intensity focused transducer is backward projected to reconstruct the pressure distributions on the focal and a pre-focal plane, which are shown to be in good agreement with the measurement. In contrast, the conventional linear holography produces erroneous results in this case where the nonlinearity involved is strong. Forward acoustic field projection was also carried out to further verify the algorithm. PMID:23654362

  9. LMR Transient Calculation Code System (version 5).

    1993-09-01

    Version: 00 The Liquid Metal Reactor (LMR) may undergo an unscrammed Transient Over-Power (TOP) or a Loss of Heat Sink (LOHS) type of accident involving power, temperature, and reactivity changes. The LTC (LMR Transient Calculation) Program calculates the time dependent reactor temperatures, reactivities, and power of the LMR after the initiation of the accident. A printout of the results including the input table of data is offered after the program run. No graphics are usedmore » in the program and the LTC.EXE (Quick Basic compiled) can make use of a math co-processor if available (GW Basic doesn't).« less

  10. Experimental verification of transient nonlinear acoustical holography.

    PubMed

    Jing, Yun; Cannata, Jonathan; Wang, Tianren

    2013-05-01

    This paper presents an experimental study on nonlinear transient acoustical holography. The validity and effectiveness of a recently proposed nonlinear transient acoustical holography algorithm is evaluated in the presence of noise. The acoustic field measured on a post-focal plane of a high-intensity focused transducer is backward projected to reconstruct the pressure distributions on the focal and a pre-focal plane, which are shown to be in good agreement with the measurement. In contrast, the conventional linear holography produces erroneous results in this case where the nonlinearity involved is strong. Forward acoustic field projection was also carried out to further verify the algorithm.

  11. Transient astronomy with the Gaia satellite.

    PubMed

    Hodgkin, Simon T; Wyrzykowski, Łukasz; Blagorodnova, Nadejda; Koposov, Sergey

    2013-06-13

    Gaia is a cornerstone European Space Agency astrometry space mission and a successor to the Hipparcos mission. Gaia will observe the whole sky for 5 years, providing a serendipitous opportunity for the discovery of large numbers of transient and anomalous events, e.g. supernovae, novae and microlensing events, gamma-ray burst afterglows, fallback supernovae, as well as theoretical or unexpected phenomena. In this paper, we discuss our preparations to use Gaia to search for transients at optical wavelengths, and briefly describe the early detection, classification and prompt publication of anomalous sources.

  12. Transient aspects of stream interface signatures

    SciTech Connect

    Crooker, N.U.; Shodhan, S.; Forsyth, R.J.; Burton, M.E.; Gosling, J.T.; Fitzenreiter, R.J.; Lepping, R.P.

    1999-06-01

    Although stream interfaces are steady-state, corotating boundaries between slow and fast solar wind, their signatures are sometimes associated with transient features. Here the authors illustrate two modes of association: interfaces trailing interplanetary coronal mass ejections (ICMEs) at 1 AU and interfaces within ICMEs in the range 4--5 AU. The former are readily understood as boundaries between transient slow wind and steady-state fast wind, where the ICMEs add variability to the interface signatures. The latter are puzzling and may be related to evolution of interfaces.

  13. Biocatalytic Pathway Selection in Transient Tripeptide Nanostructures.

    PubMed

    Pappas, Charalampos G; Sasselli, Ivan R; Ulijn, Rein V

    2015-07-01

    Structural adaption in living systems is achieved by competing catalytic pathways that drive assembly and disassembly of molecular components under the influence of chemical fuels. We report on a simple mimic of such a system that displays transient, sequence-dependent formation of supramolecular nanostructures based on biocatalytic formation and hydrolysis of self-assembling tripeptides. The systems are catalyzed by α-chymotrypsin and driven by hydrolysis of dipeptide aspartyl-phenylalanine-methyl ester (the sweetener aspartame, DF-OMe). We observed switch-like pathway selection, with the kinetics and consequent lifetime of transient nanostructures controlled by the peptide sequence. In direct competition, kinetic (rather than thermodynamic) component selection is observed.

  14. Workshop targets development of geodetic transient detection methods: 2009 SCEC Annual Meeting: Workshop on transient anomalous strain detection; Palm Springs, California, 12-13 September 2009

    USGS Publications Warehouse

    Murray-Moraleda, Jessica R.; Lohman, Rowena

    2010-01-01

    The Southern California Earthquake Center (SCEC) is a community of researchers at institutions worldwide working to improve understanding of earthquakes and mitigate earthquake risk. One of SCEC's priority objectives is to “develop a geodetic network processing system that will detect anomalous strain transients.” Given the growing number of continuously recording geodetic networks consisting of hundreds of stations, an automated means for systematically searching data for transient signals, especially in near real time, is critical for network operations, hazard monitoring, and event response. The SCEC Transient Detection Test Exercise began in 2008 to foster an active community of researchers working on this problem, explore promising methods, and combine effective approaches in novel ways. A workshop was held in California to assess what has been learned thus far and discuss areas of focus as the project moves forward.

  15. Transient Elastography in Clinical Detection of Liver Cirrhosis: A Systematic Review and Meta-analysis

    PubMed Central

    Geng, Xiao-Xia; Huang, Ren-Gang; Lin, Jian-Mei; Jiang, Nan; Yang, Xing-Xiang

    2016-01-01

    Background/Aims: Transient elastography is a noninvasive method for measuring liver fibrosis. This meta-analysis assesses the diagnostic performance of transient elastography of detecting liver cirrhosis in patients with liver disease. Patients and Methods: We searched MEDLINE, Cochrane, EMBASE databases until Jan 31, 2015, using the following search terms: elastography and liver cirrhosis. Included studies assessed patients with a diagnosis of liver cirrhosis, with an index test of transient elastography, and with the reference standard being a histopathological exam by liver biopsy. Sensitivity analysis and assessment of risk of bias and publication bias were performed. Results: Fifty-seven studies were included in the meta-analysis with a total of 10,504 patients. The pooled estimate for the sensitivity of transient elastography for detecting liver fibrosis was 81% and the specificity was 88%. The imputed diagnostic odds ratio (DOR) was 26.08 and the area under the receiver-operating characteristic (AUROC) curve was 0.931. Conclusion: Our findings indicate that transient elastography shows good sensitivity, specificity and a high accuracy for detecting liver cirrhosis. Transient elastography can be used as an additional method for the clinical diagnosis of liver fibrosis and cirrhosis. PMID:27488324

  16. A point implicit time integration technique for slow transient flow problems

    SciTech Connect

    Kadioglu, Samet Y.; Berry, Ray A.; Martineau, Richard C.

    2015-05-01

    We introduce a point implicit time integration technique for slow transient flow problems. The method treats the solution variables of interest (that can be located at cell centers, cell edges, or cell nodes) implicitly and the rest of the information related to same or other variables are handled explicitly. The method does not require implicit iteration; instead it time advances the solutions in a similar spirit to explicit methods, except it involves a few additional function(s) evaluation steps. Moreover, the method is unconditionally stable, as a fully implicit method would be. This new approach exhibits the simplicity of implementation of explicit methods and the stability of implicit methods. It is specifically designed for slow transient flow problems of long duration wherein one would like to perform time integrations with very large time steps. Because the method can be time inaccurate for fast transient problems, particularly with larger time steps, an appropriate solution strategy for a problem that evolves from a fast to a slow transient would be to integrate the fast transient with an explicit or semi-implicit technique and then switch to this point implicit method as soon as the time variation slows sufficiently. We have solved several test problems that result from scalar or systems of flow equations. Our findings indicate the new method can integrate slow transient problems very efficiently; and its implementation is very robust.

  17. Transient analysis of acoustically derived pressure and rate data

    SciTech Connect

    Kabir, C.S.; Kuchuk, F.J.; Hasan, A.R.

    1988-09-01

    A pressure-buildup test conducted on a sucker-rod pumping well is often by long-duration wellbore storage. In fact, this distortion could be so severe that even a week's shut-in period may not allow a semilog analysis. A longer shut-in period becomes economically discouraging because of lost production. Low energy and low transmissivity in the reservoir, coupled with increased fluid compressibility, contribute to this long-duration storage phenomenon. One way of reducing the storage effect clearly lies in the simultaneous analysis of downhole pressure and flow rate, estimated from casinghead pressure and rising annular liquid-level measurement made by acoustic well sounding (AWS). Ascertaining the quality of the indirectly measured pressure and rate data constitutes one of the objectives of this study. Several methods exist to translate the AWS measurement to downhole pressure and rate data for the subsequent transient analysis. The authors show that even an empirical hydrodynamic correlation provides satisfactory transient-pressure/flow-rate data for convolution and deconvolution analyses for moderate pumping-liquid columns. When long annular liquid columns are encountered, translating the AWS measurement with a mechanistically based hydrodynamic model appears to be a prudent approach. Interpretation of several transient tests show that automated convolved-type-curve or history matching of field data is a powerful tool for reservoir-parameter (total mobility, skin, fracture half-length, and storage coefficient) estimation. A simple algorithm for computing the Laplace transform of the wellbore pressure for an infinite-conductivity vertically fractured well in an infinite reservoir is developed in this work for a rapid, iterative-type computation used in automated convolved-type-curve analysis.

  18. TRANSIENT HEAT TRANSFER MODEL FOR SRS WASTE TANK OPERATIONS

    SciTech Connect

    Lee, S; Richard Dimenna, R

    2007-03-27

    A transient heat balance model was developed to assess the impact of a Submersible Mixer Pump (SMP) on waste temperature during the process of waste mixing and removal for the Type-I Savannah River Site (SRS) tanks. The model results will be mainly used to determine the SMP design impacts on the waste tank temperature during operations and to develop a specification for a new SMP design to replace existing long-shaft mixer pumps used during waste removal. The model will also be used to provide input to the operation planning. This planning will be used as input to pump run duration in order to maintain temperature requirements within the tank during SMP operation. The analysis model took a parametric approach. A series of the modeling analyses was performed to examine how submersible mixer pumps affect tank temperature during waste removal operation in the Type-I tank. The model domain included radioactive decay heat load, two SMP's, and one Submersible Transfer Pump (STP) as heat source terms. The present model was benchmarked against the test data obtained by the tank measurement to examine the quantitative thermal response of the tank and to establish the reference conditions of the operating variables under no SMP operation. The results showed that the model predictions agreed with the test data of the waste temperatures within about 10%. Transient modeling calculations for two potential scenarios of sludge mixing and removal operations have been made to estimate transient waste temperatures within a Type-I waste tank. When two 200-HP submersible mixers and 12 active cooling coils are continuously operated in 100-in tank level and 40 C initial temperature for 40 days since the initiation of mixing operation, waste temperature rises about 9 C in 48 hours at a maximum. Sensitivity studies for the key operating variables were performed. The sensitivity results showed that the chromate cooling coil system provided the primary cooling mechanism to remove process

  19. Risk factors of transient ischemic attack: An overview

    PubMed Central

    Khare, Supreet

    2016-01-01

    Transient ischemic attack (TIA) is a transient episode of neurologic dysfunction caused due to loss of blood flow to the brain or spinal cord without acute infarction. Depending on the area of the brain involved, symptoms of TIA vary widely from patient to patient. Since the blockage period in TIA is very short-lived, there is no permanent damage. Risk factors for TIA include family history of stroke or TIA, age above 55 years or older, higher risk of TIA in males than females, high blood pressure, diabetes mellitus, and tobacco smoking. Genetics, race, and imbalance in lipid profile are other risk factors of TIA. TIA is usually diagnosed after taking a thorough history and a physical examination. Several radiological tests such as computed tomography and magnetic resonance imaging are useful in the evaluation of patients who have had a TIA. Ultrasound of the neck and an echocardiogram of the heart are other tests useful in the diagnosis and evaluation of the attack. The treatment following acute recovery from a TIA depends on the underlying cause. Patients who have more than 70% stenosis of the carotid artery, removal of atherosclerotic plaque is usually done by carotid endarterectomy surgery. One-third of the people with TIA can later have recurrent TIAs and one-third can have a stroke because of permanent nerve cell loss. Having a TIA is a risk factor for eventually having a stroke. Educating the patients and inculcating lifestyle modifications in them are initial steps to minimize the prevalence of transient ischemic attack. PMID:27134474

  20. Risk factors of transient ischemic attack: An overview.

    PubMed

    Khare, Supreet

    2016-01-01

    Transient ischemic attack (TIA) is a transient episode of neurologic dysfunction caused due to loss of blood flow to the brain or spinal cord without acute infarction. Depending on the area of the brain involved, symptoms of TIA vary widely from patient to patient. Since the blockage period in TIA is very short-lived, there is no permanent damage. Risk factors for TIA include family history of stroke or TIA, age above 55 years or older, higher risk of TIA in males than females, high blood pressure, diabetes mellitus, and tobacco smoking. Genetics, race, and imbalance in lipid profile are other risk factors of TIA. TIA is usually diagnosed after taking a thorough history and a physical examination. Several radiological tests such as computed tomography and magnetic resonance imaging are useful in the evaluation of patients who have had a TIA. Ultrasound of the neck and an echocardiogram of the heart are other tests useful in the diagnosis and evaluation of the attack. The treatment following acute recovery from a TIA depends on the underlying cause. Patients who have more than 70% stenosis of the carotid artery, removal of atherosclerotic plaque is usually done by carotid endarterectomy surgery. One-third of the people with TIA can later have recurrent TIAs and one-third can have a stroke because of permanent nerve cell loss. Having a TIA is a risk factor for eventually having a stroke. Educating the patients and inculcating lifestyle modifications in them are initial steps to minimize the prevalence of transient ischemic attack.

  1. Analyses of Transient and Tertiary Small Punch Creep Deformation of 316LN Stainless Steel

    NASA Astrophysics Data System (ADS)

    Ganesh Kumar, J.; Ganesan, V.; Laha, K.

    2016-09-01

    Creep deformation behavior of 316LN stainless steel (SS) under small punch creep (SPC) and uniaxial creep test has been assessed and compared at 923 K (650 °C). The transient and tertiary creep deformation behaviors have been analyzed according to the equation proposed for SPC deflection, δ = δ0 + δ_{{T}} \\cdot (1 - {{e}}^{ - κ \\cdot t} ) + dot{δ }_{{s}} t + δ3 {{e}}^{{[ {φ ( {t - t_{{r}} } )} ]}} on the basis of Dobes and Cadek equation for uniaxial creep strain. Trends in the variations of (i) rate of exhaustion of transient creep ( κ) with steady-state deflection rate ( dot{δ }_{{s}} ) (ii) ` κ' with time to attain steady-state deflection rate, and (iii) initial creep deflection rate with steady-state deflection rate implied that transient SPC deformation obeyed first-order reaction rate theory. The rate of exhaustion of transient creep ( r') values that were determined from uniaxial creep tests were correlated with those obtained from SPC tests. Master curves representing transient creep deformation in both SPC and uniaxial creep tests have been derived and their near coincidence brings unique equivalence between both the test techniques. The relationships between (i) rate of acceleration of tertiary creep ( φ) and steady-state deflection rate, (ii) ` φ' and time spent in tertiary stage, and (iii) final creep deflection rate and steady-state deflection rate revealed that first-order reaction rate theory governed SPC deformation throughout the tertiary region also. Interrelationship between the transient, secondary, and tertiary creep parameters indicated that the same mechanism prevailed throughout the SPC deformation.

  2. Evaluation of Start Transient Oscillations with the J-2X Engine Gas Generator Assembly

    NASA Technical Reports Server (NTRS)

    Hulka, J. R.; Morgan, C. J.; Casiano, M. J.

    2015-01-01

    During development of the gas generator for the liquid oxygen/liquid hydrogen propellant J-2X rocket engine, distinctive and oftentimes high-amplitude pressure oscillations and hardware vibrations occurred during the start transient of nearly every workhorse gas generator assembly test, as well as during many tests of engine system hardware. These oscillations appeared whether the steady-state conditions exhibited stable behavior or not. They occurred similarly with three different injector types, and with every combustion chamber configuration tested, including chamber lengths ranging over a 5:1 range, several different nozzle types, and with or without a side branch line simulating a turbine spin start gas supply line. Generally, two sets of oscillations occurred, one earlier in the start transient and at higher frequencies, and the other almost immediately following and at lower frequencies. Multiple dynamic pressure measurements in the workhorse combustion chambers indicated that the oscillations were associated with longitudinal acoustic modes of the combustion chambers, with the earlier and higher frequency oscillation usually related to the second longitudinal acoustic mode and the later and lower frequency oscillation usually related to the first longitudinal acoustic mode. Given that several early development gas generator assemblies exhibited unstable behavior at frequencies near the first longitudinal acoustic modes of longer combustion chambers, the start transient oscillations are presumed to provide additional insight into the nature of the combustion instability mechanisms. Aspects of the steadystate oscillations and combustion instabilities from development and engine system test programs have been reported extensively in the three previous JANNAF Liquid Propulsion Subcommittee meetings (see references below). This paper describes the hardware configurations, start transient sequence operations, and transient and dynamic test data during the start

  3. Concentrating solar collector-performance tests

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Report summarizes test results from evaluation of concentrating solar collector thermal performance, from transient behavior, and incident-of-angle behavior. Tests were conducted using National Bureau of Standards recommedations and specifications.

  4. Comparison of pressure transient response in intensely and sparsely fractured reservoirs

    SciTech Connect

    Johns, R.T.

    1989-04-01

    A comprehensive analytical model is presented to study the pressure transient behavior of a naturally fractured reservoir with a continuous matrix block size distribution. Geologically realistic probability density functions of matrix block size are used to represent reservoirs of varying fracture intensity and uniformity. Transient interporosity flow is assumed and interporosity skin is incorporated. Drawdown and interference pressure transient tests are investigated. The results show distinctions in the pressure response from intensely and sparsely fractured reservoirs in the absence of interporosity skin. Also, uniformly and nonuniformly fractured reservoirs exhibit distinct responses, irrespective of the degree of fracture intensity. The pressure response in a nonuniformly fractured reservoir with large block size variability, approaches a nonfractured (homogeneous) reservoir response. Type curves are developed to estimate matrix block size variability and the degree of fracture intensity from drawdown and interference well tests.

  5. Mitigation of thermal transients by tube bundle inlet plenum design. [LMFBR

    SciTech Connect

    Oras, J.J.; Kasza, K.E.

    1984-06-01

    A multiphase program aimed at investigating the importance of thermal buoyancy to LMFBR steam-generator and heat-exchanger thermal hydraulics under low-flow transient conditions is being conducted in the Argonne Mixing Components Test Facility (MCTF) on a 60/sup 0/ sector shell-side flow model of the Westinghouse straight-tube steam generator being developed under the US/DOE large-component development program. A series of shell-side constant-flow thermal-downramp transient tests have been conducted focusing on the phenomenon of thermal-buoyancy-induced-flow channeling. In addition, it was discovered that a shell-inlet flow-distribution plenum can play a significant role in mitigating the severity of a thermal transient entering a steam generator or heat exchanger.

  6. Simulation of thermal-transient-induced-pipe-flow stratification using COMMIX-2

    SciTech Connect

    Shah, V.L.; Domanus, H.M.; Miao, C.C.; Schmitt, R.C.; Sha, W.T.

    1982-01-01

    At low-flow (high Richardson number) in a piping system with thermal transient, thermal-buoyancy-induced secondary flows exist. Three-dimensional computer codes are, therefore, necessary to model correctly the non-axisymmetric, thermally stratified flow through a piping system. This paper presents the results of the numerical simulation of thermal-hydraulic behavior in a pipe during a thermal transient. The particular transient considered was the experimental test No. PIPE2, and carried out at the Mixing Components Test Facility (MCTF). The numerical simulation was performed using COMMIX-2. COMMIX-2 is a computer code for steady/unsteady, three-dimensional, two-phase thermal-hydraulic analysis of reactor components under normal and off-normal operating conditions. The results of simulation are compared with the experimental measurements and they are in reasonable agreement with experimental data.

  7. A transient, Hex-Z nodal code corrected by discontinuity factors. Volume 1: The transient nodal code; Final report

    SciTech Connect

    Shatilla, Y.A.M.; Henry, A.F.

    1993-12-31

    This document constitutes Volume 1 of the Final Report of a three-year study supported by the special Research Grant Program for Nuclear Energy Research set up by the US Department of Energy. The original motivation for the work was to provide a fast and accurate computer program for the analysis of transients in heavy water or graphite-moderated reactors being considered as candidates for the New Production Reactor. Thus, part of the funding was by way of pass-through money from the Savannah River Laboratory. With this intent in mind, a three-dimensional (Hex-Z), general-energy-group transient, nodal code was created, programmed, and tested. In order to improve accuracy, correction terms, called {open_quotes}discontinuity factors,{close_quotes} were incorporated into the nodal equations. Ideal values of these factors force the nodal equations to provide node-integrated reaction rates and leakage rates across nodal surfaces that match exactly those edited from a more exact reference calculation. Since the exact reference solution is needed to compute the ideal discontinuity factors, the fact that they result in exact nodal equations would be of little practical interest were it not that approximate discontinuity factors, found at a greatly reduced cost, often yield very accurate results. For example, for light-water reactors, discontinuity factors found from two-dimensional, fine-mesh, multigroup transport solutions for two-dimensional cuts of a fuel assembly provide very accurate predictions of three-dimensional, full-core power distributions. The present document (volume 1) deals primarily with the specification, programming and testing of the three-dimensional, Hex-Z computer program. The program solves both the static (eigenvalue) and transient, general-energy-group, nodal equations corrected by user-supplied discontinuity factors.

  8. Transient Dynamic Mechanical Analysis of Resilin-based Elastomeric Hydrogels

    NASA Astrophysics Data System (ADS)

    Li, Linqing; Kiick, Kristi

    2014-04-01

    The outstanding high-frequency properties of emerging resilin-like polypeptides (RLPs) have motivated their development for vocal fold tissue regeneration and other applications. Recombinant RLP hydrogels show efficient gelation, tunable mechanical properties, and display excellent extensibility, but little has been reported about their transient mechanical properties. In this manuscript, we describe the transient mechanical behavior of new RLP hydrogels investigated via both sinusoidal oscillatory shear deformation and uniaxial tensile testing. Oscillatory stress relaxation and creep experiments confirm that RLP-based hydrogels display significantly reduced stress relaxation and improved strain recovery compared to PEG-based control hydrogels. Uniaxial tensile testing confirms the negligible hysteresis, reversible elasticity and superior resilience (up to 98%) of hydrated RLP hydrogels, with Young’s modulus values that compare favorably with those previously reported for resilin and that mimic the tensile properties of the vocal fold ligament at low strain (< 15%). These studies expand our understanding of the properties of these RLP materials under a variety of conditions, and confirm the unique applicability, for mechanically demanding tissue engineering applications, of a range of RLP hydrogels.

  9. Thermal transient thermographic NDT and E of composites

    NASA Astrophysics Data System (ADS)

    Avdelidis, Nicolas P.; Almond, Darryl P.; Dobbinson, A.; Hawtin, B.; Ibarra-Castanedo, Clemente; Maldague, Xavier P.

    2004-04-01

    The necessity for more efficient and cost effective aircraft has led in the development of innovative testing and evaluation techniques. Smart and cost effective methods for evaluating the integrity of aircraft structures are necessary to both reduce manufacturing costs and out of service time of aircraft due to maintenance. Nowadays, thermal non-destructive testing and evaluation (NDT & E) techniques are frequently used in the effective assessment of composites. Such techniques are non-contact; the investigated material is heated or cooled by an external stimulus source (flash lamps, air gun, etc) and the resulting thermal transient at the surface is monitored using an infrared - thermal camera. This paper presents certain applications of thermal transient techniques relating to the investigation of composites. Different features or defects were studied: (i) notches, delaminations and fibre optics under multi-ply composite patching (bonded with FM73 adhesive film to the surface of Al 2024-T3), (ii) drilling induced defects on multi-ply laminates of HEXCEL AS4/8552 carbon fibre composites and (iii) impact damage on carbon fibre reinforced plastic (CFRP) panels and honeycomb sandwich structures (bonded with AF-163-2U.03 adhesive film). The approaches used in this study, provided first-rate results in all cases.

  10. Multibeam Gpu Transient Pipeline for the Medicina BEST-2 Array

    NASA Astrophysics Data System (ADS)

    Magro, A.; Hickish, J.; Adami, K. Z.

    2013-09-01

    Radio transient discovery using next generation radio telescopes will pose several digital signal processing and data transfer challenges, requiring specialized high-performance backends. Several accelerator technologies are being considered as prototyping platforms, including Graphics Processing Units (GPUs). In this paper we present a real-time pipeline prototype capable of processing multiple beams concurrently, performing Radio Frequency Interference (RFI) rejection through thresholding, correcting for the delay in signal arrival times across the frequency band using brute-force dedispersion, event detection and clustering, and finally candidate filtering, with the capability of persisting data buffers containing interesting signals to disk. This setup was deployed at the BEST-2 SKA pathfinder in Medicina, Italy, where several benchmarks and test observations of astrophysical transients were conducted. These tests show that on the deployed hardware eight 20 MHz beams can be processed simultaneously for 640 Dispersion Measure (DM) values. Furthermore, the clustering and candidate filtering algorithms employed prove to be good candidates for online event detection techniques. The number of beams which can be processed increases proportionally to the number of servers deployed and number of GPUs, making it a viable architecture for current and future radio telescopes.

  11. Transient dynamic mechanical properties of resilin-based elastomeric hydrogels

    PubMed Central

    Li, Linqing; Kiick, Kristi L.

    2014-01-01

    The outstanding high-frequency properties of emerging resilin-like polypeptides (RLPs) have motivated their development for vocal fold tissue regeneration and other applications. Recombinant RLP hydrogels show efficient gelation, tunable mechanical properties, and display excellent extensibility, but little has been reported about their transient mechanical properties. In this manuscript, we describe the transient mechanical behavior of new RLP hydrogels investigated via both sinusoidal oscillatory shear deformation and uniaxial tensile testing. Oscillatory stress relaxation and creep experiments confirm that RLP-based hydrogels display significantly reduced stress relaxation and improved strain recovery compared to PEG-based control hydrogels. Uniaxial tensile testing confirms the negligible hysteresis, reversible elasticity and superior resilience (up to 98%) of hydrated RLP hydrogels, with Young's modulus values that compare favorably with those previously reported for resilin and that mimic the tensile properties of the vocal fold ligament at low strain (<15%). These studies expand our understanding of the properties of these RLP materials under a variety of conditions, and confirm the unique applicability, for mechanically demanding tissue engineering applications, of a range of RLP hydrogels. PMID:24809044

  12. Transient inhibitory seizures mimicking crescendo TIAs.

    PubMed

    Lee, H; Lerner, A

    1990-01-01

    Somatic inhibitory seizures are thought to occur rarely. We describe a patient with somatic inhibitory seizures who initially presented with a clinical picture of crescendo transient ischemic attacks. He did not improve with anticoagulation, but the episodes ceased promptly after the administration of an anticonvulsant.

  13. Intermittent/transient faults in digital systems

    NASA Technical Reports Server (NTRS)

    Masson, G. M.; Glazer, R. E.

    1982-01-01

    Containment set techniques are applied to 8085 microprocessor controllers so as to transform a typical control system into a slightly modified version, shown to be crashproof: after the departure of the intermittent/transient fault, return to one proper control algorithm is assured, assuming no permanent faults occur.

  14. Laser spectroscopy and dynamics of transient species

    SciTech Connect

    Clouthier, D.J.

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  15. Thermally triggered degradation of transient electronic devices.

    PubMed

    Park, Chan Woo; Kang, Seung-Kyun; Hernandez, Hector Lopez; Kaitz, Joshua A; Wie, Dae Seung; Shin, Jiho; Lee, Olivia P; Sottos, Nancy R; Moore, Jeffrey S; Rogers, John A; White, Scott R

    2015-07-01

    Thermally triggered transient electronics using wax-encapsulated acid, which enable rapid device destruction via acidic degradation of the metal electronic components are reported. Using a cyclic poly(phthalaldehyde) (cPPA) substrate affords a more rapid destruction of the device due to acidic depolymerization of cPPA.

  16. Video Storytelling in a Transient, Volunteer Organization

    ERIC Educational Resources Information Center

    Katzeff, Cecilia; Ware, Vanessa

    2007-01-01

    To make sense of and learn about work environments, people actively construct their own knowledge and share stories of their experience. Telling stories is particularly challenging in a transient organization where people are hired on a voluntary, temporary basis. Such is the case of a nonprofit music festival organization in Sweden, which is…

  17. Structure determination of transient transcription complexes.

    PubMed

    Cramer, Patrick

    2016-08-15

    The determination of detailed 3D structures of large and transient multicomponent complexes remains challenging. Here I describe the approaches that were used and developed by our laboratory to achieve structure solution of eukaryotic transcription complexes. I hope this collection serves as a resource for structural biologists seeking solutions for difficult structure determination projects. PMID:27528766

  18. Interpreting signals from astrophysical transient experiments

    PubMed Central

    O’Brien, Paul T.; Smartt, Stephen J.

    2013-01-01

    Time-domain astronomy has come of age with astronomers now able to monitor the sky at high cadence, both across the electromagnetic spectrum and using neutrinos and gravitational waves. The advent of new observing facilities permits new science, but the ever-increasing throughput of facilities demands efficient communication of coincident detections and better subsequent coordination among the scientific community so as to turn detections into scientific discoveries. To discuss the revolution occurring in our ability to monitor the Universe and the challenges it brings, on 25–26 April 2012, a group of scientists from observational and theoretical teams studying transients met with representatives of the major international transient observing facilities at the Kavli Royal Society International Centre, UK. This immediately followed the Royal Society Discussion Meeting ‘New windows on transients across the Universe’ held in London. Here, we present a summary of the Kavli meeting at which the participants discussed the science goals common to the transient astronomy community and analysed how to better meet the challenges ahead as ever more powerful observational facilities come on stream. PMID:23630383

  19. Neurodevelopmental outcome of transient neonatal intracerebral echodensities.

    PubMed

    Appleton, R E; Lee, R E; Hey, E N

    1990-01-01

    The later neurodevelopmental progress of 15 babies who had neonatal periventricular echodensities or flares in the absence of any intraventricular bleeding or subsequent cystic degeneration was studied. At follow up four infants had neurological abnormalities, including spastic diplegia (n = 2). These findings suggest that transient flares may represent mild periventricular leucomalacia with consequent mild neurological dysfunction. PMID:2407199

  20. Detecting aseismic strain transients from seismicity data

    USGS Publications Warehouse

    Llenos, A.L.; McGuire, J.J.

    2011-01-01

    Aseismic deformation transients such as fluid flow, magma migration, and slow slip can trigger changes in seismicity rate. We present a method that can detect these seismicity rate variations and utilize these anomalies to constrain the underlying variations in stressing rate. Because ordinary aftershock sequences often obscure changes in the background seismicity caused by aseismic processes, we combine the stochastic Epidemic Type Aftershock Sequence model that describes aftershock sequences well and the physically based rate- and state-dependent friction seismicity model into a single seismicity rate model that models both aftershock activity and changes in background seismicity rate. We implement this model into a data assimilation algorithm that inverts seismicity catalogs to estimate space-time variations in stressing rate. We evaluate the method using a synthetic catalog, and then apply it to a catalog of M???1.5 events that occurred in the Salton Trough from 1990 to 2009. We validate our stressing rate estimates by comparing them to estimates from a geodetically derived slip model for a large creep event on the Obsidian Buttes fault. The results demonstrate that our approach can identify large aseismic deformation transients in a multidecade long earthquake catalog and roughly constrain the absolute magnitude of the stressing rate transients. Our method can therefore provide a way to detect aseismic transients in regions where geodetic resolution in space or time is poor. Copyright 2011 by the American Geophysical Union.

  1. Interpreting signals from astrophysical transient experiments.

    PubMed

    O'Brien, Paul T; Smartt, Stephen J

    2013-06-13

    Time-domain astronomy has come of age with astronomers now able to monitor the sky at high cadence, both across the electromagnetic spectrum and using neutrinos and gravitational waves. The advent of new observing facilities permits new science, but the ever-increasing throughput of facilities demands efficient communication of coincident detections and better subsequent coordination among the scientific community so as to turn detections into scientific discoveries. To discuss the revolution occurring in our ability to monitor the Universe and the challenges it brings, on 25-26 April 2012, a group of scientists from observational and theoretical teams studying transients met with representatives of the major international transient observing facilities at the Kavli Royal Society International Centre, UK. This immediately followed the Royal Society Discussion Meeting 'New windows on transients across the Universe' held in London. Here, we present a summary of the Kavli meeting at which the participants discussed the science goals common to the transient astronomy community and analysed how to better meet the challenges ahead as ever more powerful observational facilities come on stream. PMID:23630383

  2. Inhomogeneous Forcing and Transient Climate Sensitivity

    NASA Technical Reports Server (NTRS)

    Shindell, Drew T.

    2014-01-01

    Understanding climate sensitivity is critical to projecting climate change in response to a given forcing scenario. Recent analyses have suggested that transient climate sensitivity is at the low end of the present model range taking into account the reduced warming rates during the past 10-15 years during which forcing has increased markedly. In contrast, comparisons of modelled feedback processes with observations indicate that the most realistic models have higher sensitivities. Here I analyse results from recent climate modelling intercomparison projects to demonstrate that transient climate sensitivity to historical aerosols and ozone is substantially greater than the transient climate sensitivity to CO2. This enhanced sensitivity is primarily caused by more of the forcing being located at Northern Hemisphere middle to high latitudes where it triggers more rapid land responses and stronger feedbacks. I find that accounting for this enhancement largely reconciles the two sets of results, and I conclude that the lowest end of the range of transient climate response to CO2 in present models and assessments (less than 1.3 C) is very unlikely.

  3. Transient (lightning) protection for electronic measurement devices

    SciTech Connect

    Black, L.L.

    1995-12-01

    Electronic measurement devices have become a major part of the oil and gas business today. All of these devices operate on an electrical voltage. Any voltage introduced into the system that is beyond the predetermined tolerance will cause degradation of performance or in some cases failure of the device. The extent of the damage depends upon the dielectric strength of the circuit in question and upon the available energy. As electronic measurement devices are further developed to incorporate more solid state circuitry and operate at lower voltage levels the more susceptible they become to transients. Along with transient protection, the user must also be concerned with intrinsic safety requirements of the device to be protected. The devices and techniques used to protect the equipment from transients do not, in all cases, guarantee the user certification for use in hazardous environments. As a note of reference, some of the techniques listed in this paper as examples would not be allowed in hazardous areas without the addition of other devices to further isolate or clamp the available energy to a safe level. In other words, as the industry moves forward to improve the overall accuracy of the measurement system and adds data availability via communication networks, the transient protection scheme must become more sophisticated.

  4. Circuit controls transients in SCR inverters

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1964-01-01

    Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.

  5. Transient Non Lin Deformation in Fractured Rock

    1998-10-14

    MATLOC is a nonlinear, transient, two-dimensional (planer and axisymmetric), thermal stress, finite-element code designed to determine the deformation within a fractured rock mass. The mass is modeled as a nonlinear anistropic elastic material which can exhibit stress-dependent bi-linear locking behavior.

  6. Transient Elastography for Assessment of Liver Fibrosis and Steatosis: An Evidence-Based Analysis

    PubMed Central

    Brener, S

    2015-01-01

    Background Liver fibrosis is a sign of advanced liver disease and is often an indication for treatment. The current standard for diagnosing liver fibrosis and steatosis is biopsy, but noninvasive alternatives are available; one of the most common is transient elastography (FibroScan). Objectives The objective of this analysis was to assess the diagnostic accuracy and clinical utility of transient elastography alone for liver fibrosis and with controlled attenuation parameter (CAP) for steatosis in patients with hepatitis C virus, hepatitis B virus, nonalcoholic fatty liver disease, alcoholic liver disease, or cholestatic diseases. The analysis also aimed to compare the diagnostic accuracy of transient elastography with two alternative noninvasive technologies: FibroTest and acoustic force radiation impulse (ARFI). Data Sources Ovid MEDLINE, Ovid MEDLINE In-Process, Ovid Embase, and all EBM databases were searched for all studies published prior to October 2, 2014. Review Methods An overview of reviews was conducted using a systematic search and assessment approach. The results of the included systematic reviews were summarized, analyzed, and reported for outcomes related to diagnostic accuracy and clinical utility as a measure of impact on diagnoses, therapeutic decisions, and patient outcomes. Results Fourteen systematic reviews were included, summarizing more than 150 studies. The reviews demonstrated that transient elastography (with or without CAP) has good diagnostic accuracy compared to biopsy for the assessment of liver fibrosis and steatosis. Acoustic force radiation impulse and FibroTest were not superior to transient elastography. Limitations None of the included systematic reviews reported on the clinical utility of transient elastography. Conclusions Transient elastography (with or without CAP) offers a noninvasive alternative to biopsy for the assessment of liver fibrosis and steatosis, given its comparable diagnostic accuracy. PMID:26664664

  7. The Zwicky transient facility observing system

    NASA Astrophysics Data System (ADS)

    Smith, Roger M.; Dekany, Richard G.; Bebek, Christopher; Bellm, Eric; Bui, Khanh; Cromer, John; Gardner, Paul; Hoff, Matthew; Kaye, Stephen; Kulkarni, Shrinivas; Lambert, Andrew; Levi, Michael; Reiley, Dan

    2014-07-01

    The Zwicky Transient Facility (ZTF) is a synoptic optical survey for high-cadence time-domain astronomy. Building upon the experience and infrastructure of the highly successful Palomar Transient Factory (PTF) team, ZTF will survey more than an order of magnitude faster than PTF in sky area and volume in order to identify rare, rapidly varying optical sources. These sources will include a trove of supernovae, exotic explosive transients, unusual stellar variables, compact binaries, active galactic nuclei, and asteroids. The single-visit depth of 20.4 mag is well matched to spectroscopic follow-up observations, while the co-added images will provide wide sky coverage 1.5 - 2 mag deeper than SDSS. The ZTF survey will cover the entire Northern Sky and revisit fields on timescales of a few hours, providing hundreds of visits per field each year, an unprecedented cadence, as required to detect fast transients and variability. This high-cadence survey is enabled by an observing system based on a new camera having 47 deg2 field of view - a factor of 6.5 greater than the existing PTF camera - equipped with fast readout electronics, a large, fast exposure shutter, faster telescope and dome drives, and various measures to optimize delivered image quality. Our project has already received an initial procurement of e2v wafer-scale CCDs and we are currently fabricating the camera cryostat. International partners and the NSF committed funds in June 2014 so construction can proceed as planned to commence engineering commissioning in 2016 and begin operations in 2017. Public release will allow broad utilization of these data by the US astronomical community. ZTF will also promote the development of transient and variable science methods in preparation for the seminal first light of LSST.

  8. Diagnosing transient ionization in dynamic events

    NASA Astrophysics Data System (ADS)

    Doyle, J. G.; Giunta, A.; Madjarska, M. S.; Summers, H.; O'Mullane, M.; Singh, A.

    2013-09-01

    Aims: The present study aims to provide a diagnostic line ratio that will enable the observer to determine whether a plasma is in a state of transient ionization. Methods: We use the Atomic Data and Analysis Structure (ADAS) to calculate line contribution functions for two lines, Si iv 1394 Å and O iv 1401 Å, formed in the solar transition region. The generalized collisional-radiative theory is used. It includes all radiative and electron collisional processes, except for photon-induced processes. State-resolved direct ionization and recombination to and from the next ionization stage are also taken into account. Results: For dynamic bursts with a decay time of a few seconds, the Si iv 1394 Å line can be enhanced by a factor of 2-4 in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature due to transient ionization compared to ionization equilibrium conditions. On the other hand, the O iv 1401 Å does not show such any enhancement. Thus the ratio of these two lines, which can be observed with the Interface Region Imaging Spectrograph, can be used as a diagnostic of transient ionization. Conclusions: We show that simultaneous high-cadence observations of two lines formed in the solar transition region may be used as a direct diagnostic of whether the observed plasma is in transient ionization. The ratio of these two lines can change by a factor of four in a few seconds owing to transient ionization alone.

  9. Organization of extratropical transients during El Nino

    SciTech Connect

    Hoerling, M.P. ); Ting, Mingfang )

    1994-05-01

    Four observed El Nino-Southern Oscillation (ENSO) events are studied to determine the mechanisms responsible for the anomalous extratropical atmospheric circulation during northern winter. A parallel analysis of a GCM's response to El Nino is performed in order to assess if similar mechanisms are operative in the model atmosphere. The observed stationary wave anomalies over the Pacific/North American (PNA) region are found to be similar during the four winters despite appreciable differences in sea surface temperatures. The anomalous transient vorticity fluxes are remarkably robust over the North Pacific during each even, with an eastward extension of the climatological storm track leading to strong cyclonic forcing near 40[degrees]N, 150[degrees]W. This forcing is in phase with the seasonal mean Aleutian trough anomaly suggesting the important of eddy-mean flow interaction. By comparison, the intersample variability of the GCM response over the PNA region is found to exceed the observed inter-El Nino variability. This stems primarily from a large variability in the model's anomalous transients over the North Pacific. Further analysis reveals that extratropical vorticity transients are the primary mechanism maintaining the stationary wave anomalies over the PNA region during all four observed ENSO winters. In the case of the GCM, the organization of transient eddies is ill defined over the North Pacific, a behavior indicative of model error. A physical model is proposed to explain the robustness of the tropical controlling influence of the extratropical transients in nature. A simple equatorial Pacific heat source directly forces a tropical anticyclone whose phase relative to the climatological tropical anticyclone leads to an eastward extension of the subtropical jet stream. This mechanism appears to be equally effective for a heat source located either in the central or eastern Pacific basin. 36 refs., 14 figs.

  10. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics.

    PubMed

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L

    2016-04-14

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g(-1) is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. PMID:26984120

  11. Numerical simulation of transient hypervelocity flow in an expansion tube

    NASA Technical Reports Server (NTRS)

    Jacobs, P. A.

    1992-01-01

    Several numerical simulations of the transient flow of helium in an expansion tube are presented. The aim of the exercise is to provide further information on the operational problems of the NASA Langley expansion tube. The calculations were performed with an axisymmetric Navier-Stokes code based on a finite-volume formulation and upwinding techniques. Although laminar flow and ideal bursting of the diaphragms was assumed, the simulations showed some of the important features seen in the experiments. In particular, the discontinuity in the tube diameter at the primary diaphragm station introduced a transverse perturbation to the expanding driver gas, and this perturbation was seen to propagate into the test gas under some flow conditions. The disturbances seen in the test flow can be characterized as either 'small-amplitude' noise possibly introduced during shock compression or 'large-amplitude' noise associated with the passage of the reflected head of the unsteady expansion.

  12. Individual differences in sensitivity to transient electrocutaneous stimulation

    SciTech Connect

    Larkin, W.D.; Reilly, J.P.; Kittler, L.B.

    1986-05-01

    124 subjects were tested in a procedure designed to measure sensitivity to transient currents applied cutaneously, and to assess individual characteristics accounting for sensitivity differences. College students (one male and one female group), female office workers, and male maintenance workers (electricians, carpenters, plumber, and sheet metal workers) were tested. Perception and annoyance thresholds were determined for capacitive discharged stimuli to the fingertip and forearm. Nonsensory data were taken for each individual in an attempt to account for individual sensitivity differences (occupation, sex, age, height, weight, skin temperature, finger and forearm diameter, skin hardness, customary physical activity level, and prior degree of experience with electric shock). Of these, body size was the only significant correlate of electrical sensitivity. Apparent correlations with sex and occupation were found to be artifacts of the body size relationship. A regression equation relating sensitivity to body weight is presented.

  13. Angular response calibration of the burst and transient source experiment

    NASA Technical Reports Server (NTRS)

    Lestrade, John Patrick

    1988-01-01

    The Gamma Ray Observatory includes four experiments designed to observe the gamma-ray universe. Laboratory measurements to test the response the Burst and Transient Source Experiment (BATSE) modules to gamma-ray sources that are non-axial were recently completed. The results of these observations are necessary for the correct interpretation of BATSE data obtained after it is put in Earth orbit. The launch is planned for March, 1900. Preliminary analyses of these test data show the presence of a radial dependence to the detector's light collection efficiency. It is proposed to evaluate the importance of this radial response, analyze future experimental data to derive the actual functional dependence on radius, and calculate the net effect on the output spectrum as a function of the angle of incidence.

  14. Plant data comparisons for Comanche Peak 50% load rejection transient

    SciTech Connect

    Boatwright, W.J.; Choe, W.G.; Hiltbrand, D.W.; Devore, C.V.

    1994-12-31

    The RETRAN-02 codes is used for the transient and accident analysis. Benchmarks have been performed in order to qualify the Comanche Pear Steam electric station (CPSES) RETRAN-02 model, particularly the protection and control systems , reactivity feedback, noding, and primary-to-secondary heat transfer modeling. The 50% load rejection test was performed as part of the initial start-up test sequence for CPSES-1. The results of this analysis demonstrate that the RETRAN-02 model of CPSES-1 allows for quite good predictions of (1) the primary-to-secondary heat transfer rate; (2) the core power response, including the reactivity feedback effects due to changes in moderator and fuel temperatures and control rod position; and (3) the rod control model, which correctly simulates actual plant response in which the control rods are inserted and withdrawn in response to temperature and power error signals.

  15. Ventilatory response to transient hypoxia in O2 divers.

    PubMed

    Melamed, Y; Kerem, D

    1988-05-01

    This study addresses the question of whether repeated acute exposure to hyperbaric oxygen, such as encountered in O2 diving, affects the peripheral oxygen chemosensors. Groups of nondivers, active O2 divers, and ex-O2 divers, as well as active air scuba divers, were given 1 or both of 2 tests that measure the ventilatory response to transient hypoxia. Results showed that all groups of divers have a mean response similar to or higher than that of nondivers as well as that of normal subjects, as reported in the literature. A repeat test on 10 diving candidates before and after 200 h of accrued O2 diving also did not show an impairment in the hypoxic ventilatory response. Oxygen diving within the established depth and time limits does not seem to cause cumulative damage to the peripheral O2 chemosensors.

  16. Exploring the transient sky: from surveys to simulations

    NASA Astrophysics Data System (ADS)

    Carbone, Dario

    2016-01-01

    The transient sky is very important to study the dynamics of the Universe on human timescales. Transient sources are seen in every band of the electromagnetic spectrum, from low radio frequencies to gamma-ray energies, and produced by nearby flare stars to cosmological gamma-ray bursts.We have performed a transient survey of four different fields with the LOw Frequency Array (LOFAR) at 150 MHz. LOFAR is a new generation radio interferometer which is observing at very low radio frequencies, a so far relatively unexplored frequency domain for transient searches. No credible transients were detected in our survey, but we were able to set stringent upper limits on the transient surface density using three new statistical methods. We also calculated the transient surface density as a function of the timescale of the transients, and established that the upper limits we can set vary up to two orders of magnitude for different timescales.We have explored the complex relation between flux density, timescale and transient surface density, and developed a simulation method to calculate the transient rate as a function of both the flux and the duration of transients for different shapes of their lightcurves and for a given observing strategy. This method is independent of the nature of transient sources, and the instrument or the frequency of the observations. Therefore, this provides a tool for transient surveys carried out by current and future observatories across the electromagnetic spectrum.

  17. Transient Events in Archival VLA Observations of the Galactic Center

    NASA Astrophysics Data System (ADS)

    Chiti, Anirudh; Chatterjee, S.; Wharton, R.; Cordes, J. M.; Lazio, J.; Kaplan, D. L.; Bower, G. C.; Croft, S.

    2014-01-01

    A number of different classes of stars, sub-stellar objects, and stellar remnants exhibit variability at radio wavelengths on time scales ranging from sub-seconds to hours. The direction toward the Galactic center not only has the highest stellar densities in the Galaxy, but also appears to have a range of interstellar scattering properties that may aid in the detection of new, radio-selected transient events. We have examined all archival VLA observations of the Galactic center field from 1985 to 2005 at 5 GHz and 8.4 GHz for a total of 214 hours of integration time, spanning 99 observations at 5 GHz with a typical area of 4.41E-4 square degrees and 116 observations at 8.4 GHz with a typical area of 8E-4 square degrees. We used a pipeline to search for transient events down to the shortest time scales allowed by the data (typically 10 seconds) by generating model-subtracted visibility data for each observation and then imaging the residual visibilities over short time intervals to search for outlier events. We present one radio transient event and at least 7 other promising candidates with significances ranging from 5.6 to 10.2 sigma that have passed all our tests, and discuss the possible source classes for these candidates and the event rate implications. We acknowledge support from the National Science Foundation for this work. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  18. Computational reconstitution of spine calcium transients from individual proteins

    PubMed Central

    Bartol, Thomas M.; Keller, Daniel X.; Kinney, Justin P.; Bajaj, Chandrajit L.; Harris, Kristen M.; Sejnowski, Terrence J.; Kennedy, Mary B.

    2015-01-01

    We have built a stochastic model in the program MCell that simulates Ca2+ transients in spines from the principal molecular components believed to control Ca2+ entry and exit. Proteins, with their kinetic models, are located within two segments of dendrites containing 88 intact spines, centered in a fully reconstructed 6 × 6 × 5 μm3 cube of hippocampal neuropil. Protein components include AMPA- and NMDA-type glutamate receptors, L- and R-type voltage-dependent Ca2+ channels, Na+/Ca2+ exchangers, plasma membrane Ca2+ ATPases, smooth endoplasmic reticulum Ca2+ ATPases, immobile Ca2+ buffers, and calbindin. Kinetic models for each protein were taken from published studies of the isolated proteins in vitro. For simulation of electrical stimuli, the time course of voltage changes in the dendritic spine was generated with the desired stimulus in the program NEURON. Voltage-dependent parameters were then continuously re-adjusted during simulations in MCell to reproduce the effects of the stimulus. Nine parameters of the model were optimized within realistic experimental limits by a process that compared results of simulations to published data. We find that simulations in the optimized model reproduce the timing and amplitude of Ca2+ transients measured experimentally in intact neurons. Thus, we demonstrate that the characteristics of individual isolated proteins determined in vitro can accurately reproduce the dynamics of experimentally measured Ca2+ transients in spines. The model will provide a test bed for exploring the roles of additional proteins that regulate Ca2+ influx into spines and for studying the behavior of protein targets in the spine that are regulated by Ca2+ influx. PMID:26500546

  19. Dynamic and Transient Performance of Turbofan/Turboshaft Convertible Engine With Variable Inlet Guide Vanes

    NASA Technical Reports Server (NTRS)

    McArdle, Jack G.; Barth, Richard L.; Wenzel, Leon M.; Biesiadny, Thomas J.

    1996-01-01

    A convertible engine called the CEST TF34, using the variable inlet guide vane method of power change, was tested on an outdoor stand at the NASA Lewis Research Center with a waterbrake dynamometer for the shaft load. A new digital electronic system, in conjunction with a modified standard TF34 hydromechanical fuel control, kept engine operation stable and safely within limits. All planned testing was completed successfully. Steady-state performance and acoustic characteristics were reported previously and are referenced. This report presents results of transient and dynamic tests. The transient tests measured engine response to several rapid changes in thrust and torque commands at constant fan (shaft) speed. Limited results from dynamic tests using the pseudorandom binary noise technique are also presented. Performance of the waterbrake dynamometer is discussed in an appendix.

  20. Spent fuel behavior under abnormal thermal transients during dry storage

    SciTech Connect

    Stahl, D.; Landow, M.P.; Burian, R.J.; Pasupathi, V.

    1986-01-01

    This study was performed to determine the effects of abnormally high temperatures on spent fuel behavior. Prior to testing, calculations using the CIRFI3 code were used to determine the steady-state fuel and cask component temperatures. The TRUMP code was used to determine transient heating rates under postulated abnormal events during which convection cooling of the cask surfaces was obstructed by a debris bed covering the cask. The peak rate of temperature rise during the first 6 h was calculated to be about 15/sup 0/C/h, followed by a rate of about 1/sup 0/C/h. A Turkey Point spent fuel rod segment was heated to approx. 800/sup 0/C. The segment deformed uniformly with an average strain of 17% at failure and a local strain of 60%. Pretest characterization of the spent fuel consisted of visual examination, profilometry, eddy-current examination, gamma scanning, fission gas collection, void volume measurement, fission gas analysis, hydrogen analysis of the cladding, burnup analysis, cladding metallography, and fuel ceramography. Post-test characterization showed that the failure was a pinhole cladding breach. The results of the tests showed that spent fuel temperatures in excess of 700/sup 0/C are required to produce a cladding breach in fuel rods pressurized to 500 psing (3.45 MPa) under postulated abnormal thermal transient cask conditions. The pinhole cladding breach that developed would be too small to compromise the confinement of spent fuel particles during an abnormal event or after normal cooling conditions are restored. This behavior is similar to that found in other slow ramp tests with irradiated and nonirradiated rod sections and nonirradiated whole rods under conditions that bracketed postulated abnormal heating rates. This similarity is attributed to annealing of the irradiation-strengthened Zircaloy cladding during heating. In both cases, the failure was a benign, ductile pinhole rupture.

  1. Ensemble Classifier Strategy Based on Transient Feature Fusion in Electronic Nose

    NASA Astrophysics Data System (ADS)

    Bagheri, Mohammad Ali; Montazer, Gholam Ali

    2011-09-01

    In this paper, we test the performance of several ensembles of classifiers and each base learner has been trained on different types of extracted features. Experimental results show the potential benefits introduced by the usage of simple ensemble classification systems for the integration of different types of transient features.

  2. Integrated Compartment Method appication to the transient heat transfer in gas-cooled reactor

    SciTech Connect

    Chen, N.C.J.; Yeh, G.T.

    1983-01-01

    Integrated Compartment Method (ICM), an effective numerical integration algorithm, was developed to solve the transient heat conduction coupled with convection. Application of the ICM to the mathematical model simulating a graphite test structure heated in an annular flow stream of hot helium has been successfully demonstrated. However, the model validation can not be performed until experimental data become available.

  3. Transient simulation of LOX/LH2 rocket engine, LE-7

    NASA Astrophysics Data System (ADS)

    Kanmuri, Akio; Wakamatsu, Yoshio; Kanda, Takeshi; Torii, Yoshihiro; Nagao, Ryuuji; Kitakura, Kazuhisa; Okada, Masashi; Imoto, Takayuki; Saito, Takashi; Hasegawa, Keiichi

    A start transient simulation calculation program was developed for the LE-7 LOX/LH2 rocket engine based on the quasi-steady model. Comparisons between simulation and test results are reported which show that simulation improvements and engine parameter adjustments are required. A brief description of the engine system is given.

  4. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Miller, J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-04-01

    We report the following classifications of optical transients from spectroscopic observations with the KOSMOS on the Mayall telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST).

  5. SPIRITS Discoveries of New Infrared Transients and Variables

    NASA Astrophysics Data System (ADS)

    Jencson, J. E.; Kasliwal, M. M.; Tinyanont, S.; Cao, Y.; Prince, T.; Lau, R. M.; Perley, D.; Masci, F.; Helou, G.; Armus, L.; Surace, J.; Dyk, S. D. Van; Cody, A.; Boyer, M. L.; Khan, R.; Bond, H. E.; Monson, A.; Bally, J.; Levesque, E.; Williams, R.; Whitelock, P. A.; Mohamed, S.; Gehrz, R. D.; Amodeo, S.; Shenoy, D.; Carlon, R.; Cass, A.; Corgan, D.; Dykhoff, D.; Faella, J.; Gburek, T.; Smith, N.; Cantiello, M.; Langer, N.; Ofek, E.; Johansson, J.; Parthasarathy, M.; Fox, O.; Hsiao, E.; Phillips, M.; Morrell, N.; Gonzalez, C.; Contreras, C.

    2016-04-01

    We report several recently discovered mid-infrared transients/strong variables found in the course of the Spitzer InfraRed Intensive Transients Survey (SPIRITS), using Spitzer Early Release Data (ATel #6644, #7929, #8688).

  6. Diagnostic Considerations in Patients Presenting with Transient Vision Loss.

    PubMed

    Jun, Bokkwan

    2016-01-01

    A complete history is essential for determining whether the underlying etiology of transient vision loss is from an ischemic or a nonischemic condition that originates in the eye or elsewhere. Ischemic transient vision loss constitutes a transient ischemic attack and requires a full work-up for ischemic stroke. If carotid artery stenosis is found, early intervention may improve the clinical outcome. This article highlights the diagnostic considerations in the evaluation of patients with transient vision loss. PMID:27039494

  7. Transient One-dimensional Pipe Flow Analyzer

    1986-04-08

    TOPAZ-SNLL, the Transient One- dimensional Pipe flow AnalyZer code, is a user-friendly computer program for modeling the heat transfer, fluid mechanics, and thermodynamics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. Although the flow conservation equations are assumed to be one-dimensional and transient, multidimensional features of internal fluid flow and heat transfer may be accounted for using the available quasi-steady flow correlations (e.g., Moody friction factor correlation and variousmore » form loss and heat transfer correlations). Users may also model the effects of moving system boundaries such as pistons, diaphragms, and bladders. The features of fully compressible flow are modeled, including the propagation of shocks and rarefaction waves, as well as the establishment of multiple choke points along the flow path.« less

  8. Biocatalytic Pathway Selection in Transient Tripeptide Nanostructures.

    PubMed

    Pappas, Charalampos G; Sasselli, Ivan R; Ulijn, Rein V

    2015-07-01

    Structural adaption in living systems is achieved by competing catalytic pathways that drive assembly and disassembly of molecular components under the influence of chemical fuels. We report on a simple mimic of such a system that displays transient, sequence-dependent formation of supramolecular nanostructures based on biocatalytic formation and hydrolysis of self-assembling tripeptides. The systems are catalyzed by α-chymotrypsin and driven by hydrolysis of dipeptide aspartyl-phenylalanine-methyl ester (the sweetener aspartame, DF-OMe). We observed switch-like pathway selection, with the kinetics and consequent lifetime of transient nanostructures controlled by the peptide sequence. In direct competition, kinetic (rather than thermodynamic) component selection is observed. PMID:26014441

  9. Transient sexual precocity and ovarian cysts.

    PubMed Central

    Lyon, A J; De Bruyn, R; Grant, D B

    1985-01-01

    Nine girls presenting under the age of 7 years with unsustained sexual precocity are described. Large ovarian cysts were detected by ultrasound in three and laparotomy in one. In two girls the symptoms resolved after surgical removal of the cyst; the other seven had spontaneous remission of symptoms, but in two of these transient breast development and bleeding recurred: further ovarian cyst formation was found in one of these patients. Endocrine studies performed before resolution of the cysts showed raised plasma oestradiol concentrations (64 to 440 pmol/l) in three girls and no appreciable rise in plasma luteinising hormone after gonadotrophin releasing hormone stimulation in two. We conclude that ovarian cyst formation with spontaneous resolution may cause transient sexual precocity in girls, and that ultrasound examination is an effective means of diagnosing and following these patients. Images Figure p820-b PMID:3901933

  10. Zero-gravity transient thermal mixing simulation

    NASA Technical Reports Server (NTRS)

    Lands, J. F., Jr.; Ried, R. C., Jr.

    1971-01-01

    The experimental program described is an outgrowth of independent investigations into alternate redesign concepts for the Apollo SM cryogenic oxygen storage system. The experiments were continued, after the redesign was established, to provide physical insight into transient thermal mixing in zero-gravity and to aid in the characterization of the system performance in flight. Zero-gravity heat transfer and fluid mixing were simulated experimentally through an analogy between unsteady heat conduction and species diffusion. To further support numerical analyses of the cryogenic oxygen storage system, the experimental investigation was extended to include a cubical tank geometry, representative of existing numerical models. In general, the transient flow patterns in the cubical tank are far more complex than those of the spherical tank and the extent of fluid mixing is significantly greater but less repeatable.

  11. On Transients in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.

    2011-01-01

    In detached Bridgman growth, a gap exists between the growing crystal and the crucible wall. According to crystal shape stability theory, only specific gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. The transient shapes are calculated assuming that the growth angle is constant. Anisotropy and dynamic contact angle effects are considered. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. However, heat transfer will influence the crystal-melt interface shape. The local angles and the crystal-melt-vapor triple junction are analyzed and the applicability of the Herring formula is discussed. A potential microgravity experiment is proposed which would enhance our understanding of the detached growth dynamic stability problem.

  12. Transient Growth in Internal Solitary Waves

    NASA Astrophysics Data System (ADS)

    Helfrich, Karl; Passaggia, Pierre-Yves; White, Brian

    2015-11-01

    Internal solitary waves of large amplitude are common in the atmosphere and ocean and play an important role in mixing and transport. While these waves can propagate over long distances, observations suggest they are susceptible to a range of instabilities, which promote breakdown, overturning, and mixing. To gain insight into these instabilities, we consider the optimal transient growth of a family of solitary waves, which are solutions to the Dubreil-Jacotin-Long (DJL) equation for increasing phase speed and varying background stratification. Optimal initial disturbances are computed by means of direct-adjoint iterations of the Navier-Stokes system in the Boussinesq approximation. The most amplified disturbances resemble Kelvin-Helmholtz instabilities and are localized near the bottom of the wave, where the Richardson number is minimum, and are maximized for short time horizons. The optimal transient growth of these perturbations is shown to increase with the phase speed. Implications for breakdown and mixing will be discussed.

  13. A physically transient form of silicon electronics.

    PubMed

    Hwang, Suk-Won; Tao, Hu; Kim, Dae-Hyeong; Cheng, Huanyu; Song, Jun-Kyul; Rill, Elliott; Brenckle, Mark A; Panilaitis, Bruce; Won, Sang Min; Kim, Yun-Soung; Song, Young Min; Yu, Ki Jun; Ameen, Abid; Li, Rui; Su, Yewang; Yang, Miaomiao; Kaplan, David L; Zakin, Mitchell R; Slepian, Marvin J; Huang, Yonggang; Omenetto, Fiorenzo G; Rogers, John A

    2012-09-28

    A remarkable feature of modern silicon electronics is its ability to remain physically invariant, almost indefinitely for practical purposes. Although this characteristic is a hallmark of applications of integrated circuits that exist today, there might be opportunities for systems that offer the opposite behavior, such as implantable devices that function for medically useful time frames but then completely disappear via resorption by the body. We report a set of materials, manufacturing schemes, device components, and theoretical design tools for a silicon-based complementary metal oxide semiconductor (CMOS) technology that has this type of transient behavior, together with integrated sensors, actuators, power supply systems, and wireless control strategies. An implantable transient device that acts as a programmable nonantibiotic bacteriocide provides a system-level example.

  14. Deflagration transient study of the CIF incinerator

    SciTech Connect

    Hang, T.

    2000-01-03

    The Consolidated Incineration Facility (CIF) treats solid and liquid RCRA hazardous and mixed wastes generated at the Savannah River Site (SRS). The transient responses of the CIF system to a deflagration, caused by an accidental charge of a modest quantity of solvent (e.g. toluene) into the rotary kiln, were a major safety concern. Using a dynamic computer model, a study was conducted to analyze the transient system responses to the rapid temperature and pressure surge in the kiln. The objective of the study was to determined the maximum pressure, temperature, and gas flow rate in each CIF component (rotary kiln, secondary combustion chamber, quencher, scrubber/cyclone, mist eliminator, reheaters, HEPAs, and ID fans). The resulting data provided a basis for the subsequent structural analysis. This paper will describe the CIF deflagration study in some detail, and present the results of the simulation scenarios.

  15. Transient phenomena in rotary-kiln incineration

    SciTech Connect

    Linak, W.P.; Kilgroe, J.D.; McSorley, J.A.; Wendt, J.O.L.; Dunn, J.E.

    1989-01-01

    This paper describes results of an ongoing experimental investigation at the U.S. EPA into the waste properties and kiln parameters that determine both the instantaneous intensity and the total magnitude of transient puffs leaving the kiln. (NOTE: The batch introduction of waste-filled drums or containers into practical rotary-kiln incinerators can lead to transient overcharging conditions which, for brevity, are here denoted as 'puffs.') The experimental apparatus utilized was a 73-kW laboratory rotary-kiln simulator. Surrogate solid wastes (plastic rods) and surrogate liquid wastes (on corncob sorbent in cardboard containers) were investigated. A statistically designed parametric study was used to determine the extent to which waste and kiln variables (e.g., charge mass, charge surface area, charge composition, kiln temperature, and kiln rotation speed) affected the intensity (hydrocarbon peak height) and magnitude (hydrocarbon peak area) of puffs.

  16. Spectral Kurtosis statistics of transient signals

    NASA Astrophysics Data System (ADS)

    Nita, G. M.

    2016-05-01

    We obtain analytical approximations for the expectation and variance of the Spectral Kurtosis estimator in the case of Gaussian and coherent transient time domain signals mixed with a quasi-stationary Gaussian background, which are suitable for practical estimations of their signal-to-noise ratio and duty-cycle relative to the instrumental integration time. We validate these analytical approximations by means of numerical simulations and demonstrate that such estimates are affected by statistical uncertainties that, for a suitable choice of the integration time, may not exceed a few per cent. Based on these analytical results, we suggest a multiscale Spectral Kurtosis spectrometer design optimized for real-time detection of transient signals, automatic discrimination based on their statistical signature, and measurement of their properties.

  17. Characterization of highly transient EUV emitting discharges

    NASA Astrophysics Data System (ADS)

    van der Mullen, Joost; Kieft, Erik; Broks, Bart

    2006-07-01

    The method of disturbed Bilateral Relations (dBR) is used to characterize highly transient plasmas that are used for the generation of Extreme Ultra Violet (EUV), i.e. radiation with a wavelength around 13.5 nm. This dBR method relates equilibrium disturbing to equilibrium restoring processes and follows the degree of equilibrium departure from the global down to the elementary plasma-level. The study gives global values of the electron density and electron temperature. Moreover, it gives a method to construct the atomic state distribution function (ASDF). This ASDF, which is responsible for the spectrum generated by the discharge, is found to be far from equilibrium. There are two reasons for this: first, systems with high charge numbers radiate strongly, second the highly transient behaviour makes that the distribution over the various ionization stages lags behind the temperature evolution.

  18. Transient One-dimensional Pipe Flow Analyzer

    SciTech Connect

    1986-04-08

    TOPAZ-SNLL, the Transient One- dimensional Pipe flow AnalyZer code, is a user-friendly computer program for modeling the heat transfer, fluid mechanics, and thermodynamics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. Although the flow conservation equations are assumed to be one-dimensional and transient, multidimensional features of internal fluid flow and heat transfer may be accounted for using the available quasi-steady flow correlations (e.g., Moody friction factor correlation and various form loss and heat transfer correlations). Users may also model the effects of moving system boundaries such as pistons, diaphragms, and bladders. The features of fully compressible flow are modeled, including the propagation of shocks and rarefaction waves, as well as the establishment of multiple choke points along the flow path.

  19. Transient expression assays in tobacco protoplasts.

    PubMed

    Vanden Bossche, Robin; Demedts, Brecht; Vanderhaeghen, Rudy; Goossens, Alain

    2013-01-01

    The sequence information generated through genome and transcriptome analysis from plant tissues has reached unprecedented sizes. Sequence homology-based annotations may provide hints for the possible function and roles of particular plant genes, but the functional annotation remains nonexistent or incomplete for many of them. To discover gene functions, transient expression assays are a valuable tool because they can be done more rapidly and at a higher scale than generating stably transformed tissues. Here, we describe a transient expression assay in protoplasts derived from suspension cells of tobacco (Nicotiana tabacum) for the study of the transactivation capacities of transcription factors. To enhance throughput and reproducibility, this method can be automated, allowing medium-throughput screening of interactions between large compendia of potential transcription factors and gene promoters.

  20. Transient behavior in the Lorenz model

    NASA Astrophysics Data System (ADS)

    Kravtsov, S.; Sugiyama, N.; Tsonis, A. A.

    2014-12-01

    Dynamical systems like the one described by the three-variable Lorenz model may serve as metaphors for complexity in nature. When natural systems are perturbed by external forcing factors, they tend to relax back to their equilibrium conditions after the forcing has shut off. Here we investigate the behavior of such transients in the Lorenz model by studying its trajectories initialized far away from the asymptotic attractor. Perhaps somewhat surprisingly, these transient trajectories exhibit complex routes and, among other things, sensitivity to initial conditions akin to that of the asymptotic behavior on the attractor. Thus, similar extreme events may lead to widely different variations before the perturbed system returns back to its statistical equilibrium.

  1. Time Transient Effects in Heterogeneous Permselective Systems

    NASA Astrophysics Data System (ADS)

    Green, Yoav; Park, Sinwook; Yossifon, Gilad

    2015-03-01

    The passage of an electric current through a permselective medium (membranes/nanochannels) under an applied electric field is characterized by the formation of ionic concentration gradients which result in regions of depleted and enriched ionic concentration at opposite ends of the medium, i.e. concentration polarization (CP). In this work, we study the time-transient behavior of the concentration and electric potential distributions in a realistic two dimensional and three layered system (i.e. microchannel-permselective medium-microchannel device). We provide an analytical solution for the concentration under the simplifying assumptions of local-electroneutrality, ideal permselectivity and negligible convection while the electric potential is solved numerically. It is shown that time transient effects occur over the diffusive time scale until steady-state is achieved. The numerical steady state solution is compared with previous analytical results and good quantitative behavior is observed.

  2. Transient Diabetes Insipidus Following Cardiopulmonary Bypass.

    PubMed

    Ekim, Meral; Ekim, Hasan; Yilmaz, Yunus Keser; Bolat, Ali

    2015-04-01

    Diabetes insipidus (DI) results from inadequate output of Antidiuretic Hormone (ADH) from the pituitary gland (central DI) or the inability of the kidney tubules to respond to ADH (nephrogenic DI). ADH is an octapeptide produced in the supraoptic and paraventricular nuclei of the hypothalamus and stored in the posterior lobe of the pituitary gland. Cardiopulmonary Bypass (CPB) has been shown to cause a six-fold increased circulating ADH levels 12 hours after surgery. However, in some cases, ADH release may be transiently suppressed due to cardioplegia (cardiac standstill) or CPB leading to DI. We present the postoperative course of a 60-year-old man who developed transient DI after CPB. He was successfully treated by applying nasal desmopressin therapy. Relevant biochemical parameters should be monitored closely in patients who produce excessive urine after open heart surgery.

  3. Transient phenomena in compressor stations during surge

    SciTech Connect

    Botros, K.K. )

    1994-01-01

    Transient phenomena are generally inherent in the operation of compressor stations: These are either fast or slow transients. A model describing the governing equation for the gas dynamics, control system, compressor and turbine shaft inertias has been developed. The effect of these inertias is manifested by an example of a compressor station operating near the surge control line. Another example deals with a station that has a cooler placed in the recycle path. This alters the rate at which the compressor shaft decelerates upon shutdown and may cause backward spinning depending on the relative magnitude of the shaft inertia with respect to the cooler volume. Backward spinning of compressor shaft has detrimental effects on dry seals and is undesirable. It was found that by keeping the recycle value closed upon shutdown, the rate of shaft deceleration will be reduced.

  4. Investigations on heavy ion induced Single-Event Transients (SETs) in highly-scaled FinFETs

    NASA Astrophysics Data System (ADS)

    Gaillardin, M.; Raine, M.; Paillet, P.; Adell, P. C.; Girard, S.; Duhamel, O.; Andrieu, F.; Barraud, S.; Faynot, O.

    2015-12-01

    We investigate Single-Event Transients (SET) in different designs of multiple-gate devices made of FinFETs with various geometries. Heavy ion experimental results are explained by using a thorough charge collection analysis of fast transients measured on dedicated test structures. Multi-level simulations are performed to get new insights into the charge collection mechanisms in multiple-gate devices. Implications for multiple-gate device design hardening are finally discussed.

  5. Transient and persistent photosensitivity due to musk ambrette. Clinical and photobiological studies.

    PubMed

    Ramsay, C A

    1984-10-01

    Musk ambrette caused contact photosensitivity in five patients. One patient showed transient light reactivity and four showed persistent light reactivity. Tests with artificial radiation were performed on normal skin without musk ambrette being added. All patients reacted abnormally to UV-B and three to UV-A. In particular the patient with transient light reactivity showed abnormal responses to UV-B and UV-A. The patients were not always aware of the role of sunlight in the development of their eruption and the clinical features were not always typical of a photodermatitis.

  6. Creation of a transient vapor nanogap between two fluidic reservoirs for single molecule manipulation

    NASA Astrophysics Data System (ADS)

    Polonsky, Stanislav; Balagurusamy, Venkat S. K.; Ott, John A.

    2014-08-01

    We introduce a new experimental technique for manipulating a segment of a charged macromolecule inside a transient nanogap between two fluidic reservoirs. This technique uses an FPGA-driven nanopositioner to control the coupling of a nanopipette with the liquid surface of a fluidic cell. We present results on creating a transient nanogap, triggered by a translocation of double-stranded DNA between a nanopipette and a fluidic cell, and measure the probability to find the molecule near the tip of the nanopipette after closing the gap. The developed platform will enable testing of our recent theoretical predictions for the behavior of charged macromolecule in a nanogap between two fluidic reservoirs.

  7. Transient Torque Technique for Viscosity and Electrical Conductivity Determination of Semiconducting Liquids

    NASA Technical Reports Server (NTRS)

    Li, C.; Scripa, R. N.; Ban, H.; Lin, B.; Su, C.-H.; Lehoczky, S. L.; Feth, S.; Zhu, S.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    A novel apparatus based on transient torque technique is constructed in MSFC/NASA. The apparatus uses a 125um diameter quartz fiber as torsion wire. A high sensitive angular detector is implemented to measure the deflection angle of the crucible containing the liquid. A rotating magnetic field (RMF) is used to induce a rotating flow of a conducting or semiconducting melts. By measuring the magnitude and transient behavior of the induced deflection angle, the electrical conductivity and viscosity of the melt can be measured simultaneously. High purity elements namely Hg, Ga, Zn and Te are tested at room temperature and high temperature up to 900 C.

  8. Nonlinear transient analysis via energy minimization

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.; Knight, N. F., Jr.

    1978-01-01

    The formulation basis for nonlinear transient analysis of finite element models of structures using energy minimization is provided. Geometric and material nonlinearities are included. The development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. The results indicate the effectiveness of the technique as a viable tool for this purpose.

  9. A new mechanism for lunar transient phenomena

    SciTech Connect

    Zito, R.R. )

    1989-12-01

    Lunar transient phenomena, which are changes in lunar surface brightness observed over the course of four centuries, are presently characterized by a novel mechanism in which electrodynamic effects associated with rock fracturing could account for the sporadic optical pulses noted near specific lunar features. It is suggested that only mild seismic activity, or perhaps thermal cracking, may be required for the activation of the proposed mechanism. 22 refs.

  10. Sprites, elf transients, and positive ground strokes

    SciTech Connect

    Boccippio, D.J.; Boldi, R.; Williams, E.R.

    1995-08-25

    In two summertime mesoscale convective systems (MCSs), mesospheric optical sprite phenomena were often coincident with both large-amplitude positive cloud-to-ground lightning and transient Schumann resonance excitations of the entire Earth-ionosphere cavity. These observations, together with earlier studies of MCS electrification, suggest that sprites are triggered when the rapid removal of large quantities of positive charge from an areally extensive charge layer stresses the mesosphere to dielectric breakdown. 46 refs., 7 figs., 1 tab.

  11. Monitoring transients in low inductance circuits

    DOEpatents

    Guilford, R.P.; Rosborough, J.R.

    1985-10-21

    The instant invention relates to methods of and apparatus for monitoring transients in low inductance circuits and to a probe utilized to practice said method and apparatus. More particularly, the instant invention relates to methods of and apparatus for monitoring low inductance circuits, wherein the low inductance circuits include a pair of flat cable transmission lines. The instant invention is further directed to a probe for use in monitoring pairs of flat cable transmission lines.

  12. ATLAS discovery of an optical transient

    NASA Astrophysics Data System (ADS)

    Tonry, J.; Denneau, L.; Stalder, B.; Heinze, A.; Sherstyuk, A.; Rest, A.; Smith, K. W.; Smartt, S. J.

    2016-08-01

    We report the following transient found by the ATLAS survey (see Tonry et al. ATel #8680). ATLAS is a twin 0.5m telescope system on Haleakala and Mauna Loa. The first unit is operational on Haleakala is robotically surveying the sky. Two filters are used, cyan and orange (denoted c and o, all mags in AB system), more information is on http://www.fallingstar.com.

  13. Reactivity Transients in Nuclear Research Reactors

    SciTech Connect

    2015-01-01

    Version 01 AIREMOD-RR is a point kinetics code which can simulate fast transients in nuclear research reactor cores. It can also be used for theoretical reactor dynamics studies. It is used for research reactor kinetic analysis and provides a point neutron kinetic capability. The thermal hydraulic behavior is governed by a one-dimensional heat balance equation. The calculations are restricted to a single equivalent unit cell which consists of fuel, clad and coolant.

  14. Validity of Darcy's law under transient conditions

    USGS Publications Warehouse

    Mongan, C.E.

    1985-01-01

    Darcy 's Law, which describes fluid flow through porous materials, was developed for steady flow conditions. The validity of applying this law to transient flows has been mathematically verified for most ground-water flow conditions. The verification was accomplished through application of Hankel transforms to linearized Navier-Stokes equations which described flow in a small diameter cylindrical tube. The tube was chosen to represent a single pore in a porous medium. (USGS)

  15. Tracking transient temperatures with liquid crystals

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.; Facemire, B. R.

    1975-01-01

    The theoretical basis of the use of the liquid crystal technique to obtain transient thermal data is discussed. Results of calibrations of liquid crystal temperature sensors are given. The effects of crystal aging, lighting effects, observer bias, etc., on accuracy are discussed. The sensitivity of liquid crystal tapes as sensors of dynamic temperature changes is quite high. The accuracy of the technique is determined primarily by the type of calibration apparatus used.

  16. Contributions of In-Situ Stress Transient Redistribution to Blasting Excavation Damage Zone of Deep Tunnels

    NASA Astrophysics Data System (ADS)

    Yan, Peng; Lu, Wen-bo; Chen, Ming; Hu, Ying-guo; Zhou, Chuang-bing; Wu, Xin-xia

    2015-03-01

    With the background of construction of the headrace tunnels with the deepest buried depth in China at present, by means of carefully acoustic velocity detection and analysis of Excavation Damage Zone (EDZ), the contributions to damage zones made by the effect of in situ stress transient redistribution are studied and compared with the extent of damage caused by the explosive load. Also, the numerical simulation was adopted to verify detecting the results. It turned out that the in situ stress transient redistribution during blasting has great influence on the development of EDZ of deep tunnels. The blasting excavation-induced damage zone of deep tunnels can be divided into the inner damage zone and the outer damage zone from the excavation surface into surrounding rocks. Although this damage zone dividing method is similar to the work of Martino and Chandler (2004), the consideration of developing a mechanism of the inner damage zone, especially the contribution of in situ stress transient redistribution, is totally different. The inner damage zone, which accounts for 29-57 % of the total damage zone, is mainly caused by explosive load and in situ stress transient adjustment, while the outer damage zone can be mostly attributed to the static redistribution of in situ stress. Field tests and numerical simulation indicate that the in situ stress transient redistribution effect during blasting contributes about 16-51 % to the inner damage zone in the 2# headrace tunnel of Jinping II Hydropower Station. For general cases, it can be concluded that the in situ stress transient redistribution is one of the main contributors of an excavation damage zone, and damage caused by in situ stress transient redistribution effect may exceed the damage caused by explosion load and become the main inducing factor for damage with the rise of in situ stress levels.

  17. PSST discovery of a faint transient in NGC 6012

    NASA Astrophysics Data System (ADS)

    Smith, K. W.; Wright, D.; Smartt, S. J.; Young, D. R.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-06-01

    A transient object has been discovered near NGC 6012 as part of the Pan-STARRS Survey for Transients (PSST). Information on all objects discovered by the Pan-STARRS Survey for Transients is available at http://star.pst.qub.ac.uk/ps1threepi/ (see Huber et al. ATel #7153).

  18. Mixed time integration methods for transient thermal analysis of structures

    NASA Technical Reports Server (NTRS)

    Liu, W. K.

    1983-01-01

    The computational methods used to predict and optimize the thermal-structural behavior of aerospace vehicle structures are reviewed. In general, two classes of algorithms, implicit and explicit, are used in transient thermal analysis of structures. Each of these two methods has its own merits. Due to the different time scales of the mechanical and thermal responses, the selection of a time integration method can be a difficult yet critical factor in the efficient solution of such problems. Therefore mixed time integration methods for transient thermal analysis of structures are being developed. The computer implementation aspects and numerical evaluation of these mixed time implicit-explicit algorithms in thermal analysis of structures are presented. A computationally-useful method of estimating the critical time step for linear quadrilateral element is also given. Numerical tests confirm the stability criterion and accuracy characteristics of the methods. The superiority of these mixed time methods to the fully implicit method or the fully explicit method is also demonstrated.

  19. Transient Detonation Processes in a Plastic Bonded Explosive

    NASA Astrophysics Data System (ADS)

    Thomas, Keith A.; Martin, Eric S.; Kennedy, James E.; Garcia, Ismael A.; Foster, Joseph C.

    2002-07-01

    Experiments involving the transfer of detonation from small booster charges of PBXN-5 (95% HMX and 5% Viton A) into larger charges of various plastic-bonded explosives (PBXs) have produced some surprising results and have stimulated investigation into the factors governing observed responses. To understand these results, we conducted a series of tests with different miniature detonator-booster configurations using laser velocimetry to quantify the pressure pulse that is transmitted from the PBXN-5 booster. Models were used to determine the ideal explosive behavior for comparison with the measured results. The differences are interpreted as being due to transient behavior and late-time energy release from the booster charge. We characterize these behaviors as evidence of microdetonics, where we define microdetonics as the study of less-than-CJ detonation performance due to curvature and/or transient behavior. This provides useful insights into the fundamentals of the detonation process that can feed into advanced modeling approaches such as Detonation Shock Dynamics (DSD).

  20. V-FASTR: THE VLBA FAST RADIO TRANSIENTS EXPERIMENT

    SciTech Connect

    Wayth, Randall B.; Tingay, Steven J.; Brisken, Walter F.; Deller, Adam T.; Majid, Walid A.; Thompson, David R.; Wagstaff, Kiri L.

    2011-07-10

    Recent discoveries of dispersed, non-periodic impulsive radio signals with single-dish radio telescopes have sparked significant interest in exploring the relatively uncharted space of fast transient radio signals. Here we describe V-FASTR, an experiment to perform a blind search for fast transient radio signals using the Very Long Baseline Array (VLBA). The experiment runs entirely in a commensal mode, alongside normal VLBA observations and operations. It is made possible by the features and flexibility of the DiFX software correlator that is used to process VLBA data. Using the VLBA for this type of experiment offers significant advantages over single-dish experiments, including a larger field of view, the ability to easily distinguish local radio-frequency interference from real signals, and the possibility to localize detected events on the sky to milliarcsecond accuracy. We describe our software pipeline, which accepts short integration ({approx} ms) spectrometer data from each antenna in real time during correlation and performs an incoherent dedispersion separately for each antenna, over a range of trial dispersion measures. The dedispersed data are processed by a sophisticated detector and candidate events are recorded. At the end of the correlation, small snippets of the raw data at the time of the events are stored for further analysis. We present the results of our event detection pipeline from some test observations of the pulsars B0329+54 and B0531+21 (the Crab pulsar).