WorldWideScience

Sample records for htsma-actuated surge control

  1. Time to Surge Concept and Surge Control for Acceleration Performance

    OpenAIRE

    Leufvén, Oskar; Eriksson, Lars

    2008-01-01

    Surge is a dangerous instability that can occur in compressors. It is avoided using a valve that reduces the compressor pressure. The control of this valve is important for the compressor safety but it also has a direct influence on the acceleration performance. Compressor surge control is investigated by first studying the surge phenomenon in detail. Experimental data from a dynamic compressor flow test bench and surge cycles measured on an engine is used to tune and validate a model capable...

  2. CONTROL SYSTEM SURGE OF CENTRIFUGAL COMPRESSORS

    Directory of Open Access Journals (Sweden)

    M. V. Tsabenko

    2016-07-01

    Full Text Available The article investigates the anti-surge protection systems and mathematical modeling of systems of gas compressor units on the basis of centrifugal compressors with anti-surge valve or baypass, and a mixed protection system. The review of existing systems, surge protection of gas compressor units, which revealed a number of shortcomings when using antisurge valve or baypass system. The proposed mixed system of surge protection with simultaneous use of surge valve and baypass system. The proposed sequence of the mixed system of surge protection. The above block diagram of an electromechanical system centrifugal compressor – anti-surge valve - direct current motor with an automatic control system. Obtained by use of transient surge valve baypass and mixed anti-surge system. These conclusions underline the relevance of the research and energy efficiency centrifugal compressor anti-surge protection system.

  3. Active surge control for variable speed axial compressors.

    Science.gov (United States)

    Lin, Shu; Yang, Chunjie; Wu, Ping; Song, Zhihuan

    2014-09-01

    This paper discusses active surge control in variable speed axial compressors. A compression system equipped with a variable area throttle is investigated. Based on a given compressor model, a fuzzy logic controller is designed for surge control and a proportional speed controller is used for speed control. The fuzzy controller uses measurements of the change of pressure rise as well as the change of mass flow to determine the throttle opening. The presented approach does not require the knowledge of system equilibrium or the surge line. Numerical simulations show promising results. The proposed fuzzy logic controller performs better than a backstepping controller and is capable to suppress surge at different operating points. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Modeling and control of surge and rotating stall in compressors

    Energy Technology Data Exchange (ETDEWEB)

    Gravdahl, Jan Tommy

    1998-12-31

    Compressors are used in power generation and a variety of other applications. This thesis contains new results in the field of modeling and control of rotating stall and surge in compressors. A close coupled valve is included in the Moore-Greitzer compression system model and controllers for both surge and rotating stall is derived using backstepping. Disturbances, constant and time varying, are then taken into account, and non-linear controllers are derived. Stability results are given. Then, passivity is used to derive a simple surge control law for the closed coupled valve. This propositional control law is shown to stabilize the system even in the presence of time varying disturbances in mass flow and pressure. A novel model for an axial compression system with non-constant compressor speed is derived by extending the Moore-Greitzer model. Rotating stall and surge is studied in connection with acceleration of the compressor. Finally, a model for a centrifugal compression system with time varying compressor speed is derived. The variable speed compressor characteristic is derived based on energy losses in the compressor components. Active control of surge in connection with varying speed is studied. Semi-global exponential stability of the compression system with both surge and speed control is proven. 103 refs., 38 figs., 5 tabs.

  5. 40 CFR 63.170 - Standards: Surge control vessels and bottoms receivers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Surge control vessels and... Standards: Surge control vessels and bottoms receivers. Each surge control vessel or bottoms receiver that... surge control vessel or bottoms receiver back to the process or to a control device that complies with...

  6. 40 CFR 61.242-9 - Standards: Surge control vessels and bottoms receivers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standards: Surge control vessels and... Emission Standard for Equipment Leaks (Fugitive Emission Sources) § 61.242-9 Standards: Surge control vessels and bottoms receivers. Each surge control vessel or bottoms receiver that is not routed back to...

  7. Efficacy of Cruise Control in controlling postocclusion surge with Legacy and Millennium venturi phacoemulsification machines.

    Science.gov (United States)

    Wade, Matthew; Isom, Ryan; Georgescu, Dan; Olson, Randall J

    2007-06-01

    To determine the efficacy of the Cruise Control surge-limiting device (Staar Surgical) with phacoemulsification machines known to have high levels of surge. John A. Moran Eye Center Clinical Laboratories. In an in vitro study, postocclusion anterior chamber depth changes were measured in fresh phakic human eye-bank eyes using the Alcon Legacy and Bausch & Lomb Millennium venturi machines in conjunction with the Staar Cruise Control device. Both machines were tested with 19-gauge non-Aspiration Bypass System tips at high-surge settings (500 mm Hg vacuum pressure, 75 cm bottle height, 40 mL/min flow rate for the Legacy) and low-surge settings (400 mm Hg vacuum pressure, 125 cm bottle height, 40 mL/min flow rate for the Legacy). Adjusted parameters of flow, vacuum, and irrigation were used based on previous studies to create identical conditions for each device tested. The effect of the Cruise Control device on aspiration rates was also tested with both machines at the low-surge settings. At the high setting with the addition of Cruise Control, surge decreased significantly with the Legacy but was too large to measure with the Millennium venturi. At the low setting with the addition of Cruise Control, surge decreased significantly with both machines. Surge with the Millennium decreased from more than 1.0 mm to a mean of 0.21 mm +/- 0.02 (SD) (PCruise Control and the greatest percentage decrease in the surge and aspiration rates as a result of the addition of Cruise Control. In the Legacy machine, the Cruise Control device had a statistically and clinically significant effect. Cruise Control had a large effect on fluidics as well as surge amplitude with the Millennium machine. The greater the flow or greater the initial surge, the greater the impact of the Cruise Control device.

  8. Control of the LH surge mechanism in the female pig.

    Science.gov (United States)

    Elsaesser, F; Parvizi, N; Foxcroft, G R

    1992-12-01

    The functionality of the oestrogen-positive feedback mechanism is the basis for the preovulatory LH surge and thus for regular cyclic activity in the sow. The LH surge mechanism (LH SM) gradually matures as a function of age, immature gilts display delayed, low amplitude LH surges in response to oestradiol benzoate (OB). The maturation of the LH SM apparently is ovarian oestrogen-dependent. Continuous ovarian secretions, probably oestrogens, also appear to be necessary for the final peripubertal maturation of the LH SM and to maintain the functionality of this mechanism in the sexually mature gilt. Superphysiological levels of oestrogens are, however, detrimental to the development of the LH SM. Failure of various infusions of the opioid antagonist naloxone during the surge period to enhance the magnitude of OB-induced LH surges in immature gilts does not support the idea, that central opioidergic systems are of major importance in preventing mature LH surge response at this age. However, opioids could be involved in the termination of the LH surge. Experiments using the opioid agonist morphine and the antagonist naloxone to demonstrate that opioids are involved in the generation of the LH surge in the mature gilt have so far provided equivocal data. Studies using pulsatile infusions of LHRH or of a potent LHRH-agonist during the surge period in OB-treated immature gilts, in which endogenous LHRH release was blocked by methallibure, suggest that oestradiol fails to generate mature LH surges because the gonadotrophs of the immature gilt are unable to respond to enhanced LHRH secretion during the surge period in an adult-like manner. During early lactation the LH SM cannot be activated by OB, while during late lactation a partial recovery of the LH SM occurs. Minor breed differences exist in the functionality of the LH SM during lactation between LW sows and highly fertile Chinese Meishan sows, in which lactational anoestrus is not obligatory.

  9. Control of Surge in Centrifugal Compressors by Active Magnetic Bearings Theory and Implementation

    CERN Document Server

    Yoon, Se Young; Allaire, Paul E

    2013-01-01

    Control of Surge in Centrifugal Compressors by Active Magnetic Bearings sets out the fundamentals of integrating the active magnetic bearing (AMB) rotor suspension technology in compressor systems, and describes how this relatively new bearing technology can be employed in the active control of compressor surge. The authors provide a self-contained and comprehensive review of rotordynamics and the fundamentals of the AMB technology. The active stabilization of compressor surge employing AMBs in a machine is fully explored, from the modeling of the instability and the design of feedback controllers, to the implementation and experimental testing of the control algorithms in a specially-constructed, industrial-size centrifugal compression system. The results of these tests demonstrate the great potential of the new surge control method developed in this text. This book will be useful for engineers in industries that involve turbocompressors and magnetic bearings, as well as for researchers and graduate students...

  10. Hypothalamic control of the male neonatal testosterone surge

    Science.gov (United States)

    Clarkson, Jenny; Herbison, Allan E.

    2016-01-01

    Sex differences in brain neuroanatomy and neurophysiology underpin considerable physiological and behavioural differences between females and males. Sexual differentiation of the brain is regulated by testosterone secreted by the testes predominantly during embryogenesis in humans and the neonatal period in rodents. Despite huge advances in understanding how testosterone, and its metabolite oestradiol, sexually differentiate the brain, little is known about the mechanism that actually generates the male-specific neonatal testosterone surge. This review examines the evidence for the role of the hypothalamus, and particularly the gonadotropin-releasing hormone (GnRH) neurons, in generating the neonatal testosterone surge in rodents and primates. Kisspeptin–GPR54 signalling is well established as a potent and critical regulator of GnRH neuron activity during puberty and adulthood, and we argue here for an equally important role at birth in driving the male-specific neonatal testosterone surge in rodents. The presence of a male-specific population of preoptic area kisspeptin neurons that appear transiently in the perinatal period provide one possible source of kisspeptin drive to neonatal GnRH neurons in the mouse. PMID:26833836

  11. Experimental Study on Active Control of Surge in a Centrifugal Compression System

    Directory of Open Access Journals (Sweden)

    Nie Chaoqun

    2000-01-01

    Full Text Available An experimental study has been carried out on the active control of surge in a centrifugal compression system. With a computerized on-line control scheme, the surge phenomenon is suppressed and the stable operating range of the system is extended. In order to design the active control scheme and choose the desired parameters of the control system inputs, special emphases have been placed on the development of surge inception and the nonlinear interaction between the system and the actuator. By use of the method designed in the present work, the results of active control onsurge have been demonstrated for the different B parameters, different prescribed criteria and different control frequencies.

  12. INCREASED FLEXIBILITY OF TURBO-COMPRESSORS IN NATURAL GAS TRANSMISSION THROUGH DIRECT SURGE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Robert J. McKee; Shane P. Siebenaler; Danny M. Deffenbaugh

    2005-02-25

    The objective of this Direct Surge Control project was to develop a new internal method to avoid surge of pipeline compressors. This method will safely expand the range and flexibility of compressor operations, while minimizing wasteful recycle flow at the lower end of the operating envelope. The approach is to sense the onset of surge with a probe that directly measures re-circulation at the impeller inlet. The signals from the probe are used by a controller to allow operation at low flow conditions without resorting to a predictive method requiring excessive margin to activate a recycle valve. The sensor developed and demonstrated during this project was a simple, rugged, and sensitive drag probe. Experiments conducted in a laboratory compressor clearly showed the effectiveness of the technique. Subsequent field demonstrations indicated that the increase in range without the need to recycle flow was on the order of 19% to 25%. The cost benefit of applying the direct surge control technology appears to be as much as $120 per hour per compressor for operation without the current level of recycle flow. This could amount to approximately $85 million per year for the U.S. Natural Gas Transmission industry, if direct surge control systems are applied to most pipeline centrifugal compressors.

  13. Improvement of Performance Range of Centrifugal Compressors Gas by Surge Line Modification Using Active Controller Based on Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Pezhman Mohammadi

    2012-04-01

    Full Text Available In this work, surge of prevention is a critical problem in oil and gas industries, particularly when return gas flow or gas flow reduces in transportation of gas pipelines. This paper is illustrated new results about surge control of centrifugal compressors .surge phenomenon is flow unsteady state in compressors which causes damages seriously in compressor construction. Furthermore, it also demonstrates in comparison with anti surge control ،active surge control expands stability range.Active surge control which based on fuzzy logic،is the main idea that used in this investigation. Using fuzzy controller causes an improvement in compressor's condition and increase performance range of the compressor, in addition to prevention of any instability in compressor. The simulation results is also satisfactory.

  14. Cold basal conditions during surges control flow of fringing Arctic ice caps in Greenland

    Science.gov (United States)

    Cook, Samuel; Christoffersen, Poul; Todd, Joe; Palmer, Steven

    2017-04-01

    Fringing ice caps separated from larger ice sheets are rarely studied, yet they are an important part of earth's cryosphere, which has become the largest source of global sea-level rise. Understanding marginal ice caps is crucial for being able to predict sea-level change as they are responsible for up to 20% of Greenland's mass loss for 2003-2008. Studies of fringing ice caps can furthermore provide useful insights into processes operating on glaciers that surge. Surging has been the focus of much recent glaciological work, especially with reference to thermal evolution of polythermal glaciers in High Mountain Asia and the High Arctic. This has shown that the classic divide between hydrologically-controlled surges ('hard-bed') in Alaska and thermally-regulated ('soft-bed') surges elsewhere is less stark than previously assumed. Studying marginal ice caps can therefore be valuable in several ways. The largest fringing ice cap in Greenland is Flade Isblink. Previous work has established that this ice cap is showing a range of dynamic behaviour, including subglacial lake drainage and varied patterns of mass-balance change. In particular, a substantial surge, assumed to be caused by a version of the thermally-regulated mechanism, occurred between 1996 and 2000, making the ice cap a useful case study for investigating this process. Here we investigate the surge on Flade Isblink using the open-source, Full-Stokes model Elmer/Ice to invert for basal conditions and englacial temperatures using the adjoint method. We specifically study steady-state conditions representative of the active surge phase in 2000, and the subsequent quiescent phase, using patterns of surface velocity observed in 2000, 2005, 2008 and 2015. Under constant geometry, temperature and geothermal heat, it is shown that surging increases basal freezing rates by over 60% across an area that is twice as large as the area over which the bed freezes in the quiescent phase. The process responsible for this

  15. On Active Surge Control of Compression Systems via Characteristic Linearization and Model Nonlinearity Cancellation

    Directory of Open Access Journals (Sweden)

    Yohannes S.M. Simamora

    2014-09-01

    Full Text Available A simple approach of active surge control of compression systems is presented. Specifically, nonlinear components of the pressure ratio and rotating speed states of the Moore-Greitzer model are transferred into the input vectors. Subsequently, the compressor characteristic is linearized into two modes, which describe the stable region and the unstable region respectively. As a result, the system’s state and input matrices both appear linear, to which linear realization and analysis are applicable. A linear quadratic regulator plus integrator is then chosen as closed-loop controller. By simulation it was shown that the modified model and characteristics can describe surge behavior, while the closed-loop controller can stabilize the system in the unstable operating region. The last-mentioned was achieved when massflow was 5.38 per cent less than the surge point.

  16. Karakoram glacier surge dynamics: KARAKORAM GLACIER SURGE DYNAMICS

    National Research Council Canada - National Science Library

    Quincey, D. J; Braun, M; Glasser, N. F; Bishop, M. P; Hewitt, K; Luckman, A

    2011-01-01

      Recent Karakoram glacier surges are thermally controlled Previous non-surge glaciers are showing surge-type activity Thermal conditions may be changing across the Karakoram regionally We examine...

  17. Control of the Estradiol-Induced Prolactin Surge by the Suprachiasmatic Nucleus

    NARCIS (Netherlands)

    Palm, Inge F.; van der Beek, Eline M.; Swarts, Hans J. M.; van der Vliet, Jan; Wiegant, Victor M.; Buijs, Ruud M.; Kalsbeek, Andries

    2001-01-01

    In the present study we investigated how the suprachiasmatic nucleus (SCN) controls the E(2)-induced PRL surge in female rats. First, the role of vasopressin (VP), a SCN transmitter present in medial preoptic area (MPO) projections and rhythmically released by SCN neurons, as a circadian signal for

  18. A baseline expert control system for marine gas turbine compressor surge

    OpenAIRE

    Davitt, James A.

    1989-01-01

    Approved for public release; distribution is unlimited United States Navy gas turbine ships are in need of casualty control system updating to reduce demanding conditions on engineering watch standers, to increase equipment longevity, and reduce operating costs. This thesis presents a baseline computer-based expert system controller concept developed for the critical casualty control problem of gas turbine compressor surge. The controller design rests on the building-block components of re...

  19. 40 CFR Table 2 to Subpart H of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Surge Control Vessels and Bottoms Receivers at Existing Sources 2 Table 2 to Subpart H of Part 63 Protection of Environment ENVIRONMENTAL... Equipment Leaks Pt. 63, Subpt. H, Table 2 Table 2 to Subpart H of Part 63—Surge Control Vessels and Bottoms...

  20. 40 CFR Table 1 to Subpart V of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Surge Control Vessels and Bottoms Receivers at Existing Sources 1 Table 1 to Subpart V of Part 61 Protection of Environment ENVIRONMENTAL... 1 Table 1 to Subpart V of Part 61—Surge Control Vessels and Bottoms Receivers at Existing Sources...

  1. 40 CFR Table 2 to Subpart V of... - Surge Control Vessels and Bottoms Receivers at New Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Surge Control Vessels and Bottoms Receivers at New Sources 2 Table 2 to Subpart V of Part 61 Protection of Environment ENVIRONMENTAL... 2 Table 2 to Subpart V of Part 61—Surge Control Vessels and Bottoms Receivers at New Sources Vessel...

  2. 40 CFR Table 3 to Subpart H of... - Surge Control Vessels and Bottoms Receivers at New Sources

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Surge Control Vessels and Bottoms Receivers at New Sources 3 Table 3 to Subpart H of Part 63 Protection of Environment ENVIRONMENTAL... Equipment Leaks Pt. 63, Subpt. H, Table 3 Table 3 to Subpart H of Part 63—Surge Control Vessels and Bottoms...

  3. Optimal Control of a Surge-Mode WEC in Random Waves

    Energy Technology Data Exchange (ETDEWEB)

    Chertok, Allan [Resolute Marine Energy, Inc., Boston, MA (United States); Ceberio, Olivier [Resolute Marine Energy, Inc., Boston, MA (United States); Staby, Bill [Resolute Marine Energy, Inc., Boston, MA (United States); Previsic, Mirko [Re Vision Consulting, Sacramento, CA (United States); Scruggs, Jeffrey [Univ. of Michigan, Ann Arbor, MI (United States); Van de Ven, James [Univ. of Minnesota, Minneapolis, MN (United States)

    2016-08-30

    The objective of this project was to develop one or more real-time feedback and feed-forward (MPC) control algorithms for an Oscillating Surge Wave Converter (OSWC) developed by RME called SurgeWEC™ that leverages recent innovations in wave energy converter (WEC) control theory to maximize power production in random wave environments. The control algorithms synthesized innovations in dynamic programming and nonlinear wave dynamics using anticipatory wave sensors and localized sensor measurements; e.g. position and velocity of the WEC Power Take Off (PTO), with predictive wave forecasting data. The result was an advanced control system that uses feedback or feed-forward data from an array of sensor channels comprised of both localized and deployed sensors fused into a single decision process that optimally compensates for uncertainties in the system dynamics, wave forecasts, and sensor measurement errors.

  4. Surge block method for controlling well clogging and sampling sediment during bioremediation.

    Science.gov (United States)

    Wu, Wei-Min; Watson, David B; Luo, Jian; Carley, Jack; Mehlhorn, Tonia; Kitanidis, Peter K; Jardine, Phlip M; Criddle, Craig S

    2013-11-01

    A surge block treatment method (i.e. inserting a solid rod plunger with a flat seal that closely fits the casing interior into a well and stocking it up and down) was performed for the rehabilitation of wells clogged with biomass and for the collection of time series sediment samples during in situ bioremediation tests for U(VI) immobilization at a the U.S. Department of Energy site in Oak Ridge, TN. The clogging caused by biomass growth had been controlled by using routine surge block treatment for 18 times over a nearly four year test period. The treatment frequency was dependent of the dosage of electron donor injection and microbial community developed in the subsurface. Hydraulic tests showed that the apparent aquifer transmissivity at a clogged well with an inner diameter (ID) of 10.16 cm was increased by 8-13 times after the rehabilitation, indicating the effectiveness of the rehabilitation. Simultaneously with the rehabilitation, the surge block method was successfully used for collecting time series sediment samples composed of fine particles (clay and silt) from wells with ID 1.9-10.16 cm for the analysis of mineralogical and geochemical composition and microbial community during the same period. Our results demonstrated that the surge block method provided a cost-effective approach for both well rehabilitation and frequent solid sampling at the same location. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Surge Block Method for Controlling Well Clogging and Sampling Sediment during Bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wei-min [Stanford University; Watson, David B [ORNL; Luo, Jian [Stanford University; Carley, Jack M [ORNL; Mehlhorn, Tonia L [ORNL; Kitanidis, Peter K. [Stanford University; Jardine, Philip [University of Tennessee, Knoxville (UTK); Criddle, Craig [Stanford University

    2013-01-01

    A surge block treatment method (i.e. inserting a solid rod plunger with a flat seal that closely fits the casing interior into a well and stocking it up and down) was performed for the rehabilitation of wells clogged with biomass and for the collection of time series sediment samples during in situ bioremediation tests for U(VI) immobilization at a the U.S. Department of Energy site in Oak Ridge, TN. The clogging caused by biomass growth had been controlled by using routine surge block treatment for18 times over a nearly four year test period. The treatment frequency was dependent of the dosage of electron donor injection and microbial community developed in the subsurface. Hydraulic tests showed that the apparent aquifer transmissivity at a clogged well with an inner diameter (ID) of 10.16 cm was increased by 8 13 times after the rehabilitation, indicating the effectiveness of the rehabilitation. Simultaneously with the rehabilitation, the surge block method was successfully used for collecting time series sediment samples composed of fine particles (clay and silt) from wells with ID 1.9 10.16 cm for the analysis of mineralogical and geochemical composition and microbial community during the same period. Our results demonstrated that the surge block method provided a cost-effective approach for both well rehabilitation and frequent solid sampling at the same location.

  6. Modeling the Origin and Possible Control of the Wealth Inequality Surge.

    Science.gov (United States)

    Berman, Yonatan; Shapira, Yoash; Ben-Jacob, Eshel

    2015-01-01

    The rapid increase of wealth inequality in the past few decades is a most disturbing social and economic issue of our time. In order to control, and even reverse that surge, its origin and underlying mechanisms should be revealed. One of the challenges in studying these mechanisms is to incorporate realistic individual dynamics in the population level in a self-consistent manner. Our theoretical approach meets the challenge by using interacting multi-agent master-equations to model the dynamics of wealth inequality. The model is solved using stochastic multi-agent iterated maps. Taking into account growth rate, return on capital, private savings and economic mobility, we were able to capture the historical dynamics of wealth inequality in the United States during the course of the 20th century. We show that the fraction of capital income in the national income and the fraction of private savings are the critical factors that govern the wealth inequality dynamics. In addition, we found that economic mobility plays a crucial role in wealth accumulation. Notably, we found that the major decrease in private savings since the 1980s could be associated primarily with the recent surge in wealth inequality and if nothing changes in this respect we predict further increase in wealth inequality in the future. However, the 2007-08 financial crisis brought an opportunity to restrain the wealth inequality surge by increasing private savings. If this trend continues, it may lead to prevention, and even reversing, of the ongoing inequality surge.

  7. Modeling the Origin and Possible Control of the Wealth Inequality Surge.

    Directory of Open Access Journals (Sweden)

    Yonatan Berman

    Full Text Available The rapid increase of wealth inequality in the past few decades is a most disturbing social and economic issue of our time. In order to control, and even reverse that surge, its origin and underlying mechanisms should be revealed. One of the challenges in studying these mechanisms is to incorporate realistic individual dynamics in the population level in a self-consistent manner. Our theoretical approach meets the challenge by using interacting multi-agent master-equations to model the dynamics of wealth inequality. The model is solved using stochastic multi-agent iterated maps. Taking into account growth rate, return on capital, private savings and economic mobility, we were able to capture the historical dynamics of wealth inequality in the United States during the course of the 20th century. We show that the fraction of capital income in the national income and the fraction of private savings are the critical factors that govern the wealth inequality dynamics. In addition, we found that economic mobility plays a crucial role in wealth accumulation. Notably, we found that the major decrease in private savings since the 1980s could be associated primarily with the recent surge in wealth inequality and if nothing changes in this respect we predict further increase in wealth inequality in the future. However, the 2007-08 financial crisis brought an opportunity to restrain the wealth inequality surge by increasing private savings. If this trend continues, it may lead to prevention, and even reversing, of the ongoing inequality surge.

  8. PIV investigation of the flow induced by a passive surge control method in a radial compressor

    Energy Technology Data Exchange (ETDEWEB)

    Guillou, Erwann; Gancedo, Matthieu; Gutmark, Ephraim [University of Cincinnati, Department of Aerospace Engineering, Cincinnati, OH (United States); Mohamed, Ashraf [Honeywell Turbo Technologies, Greater Los Angeles, CA (United States)

    2012-09-15

    Due to recent emission regulations, the use of turbochargers for force induction of internal combustion engines has increased. Actually, the trend in diesel engines is to downsize the engine by use of turbochargers that operate at higher pressure ratios. Unfortunately, increasing the impeller rotational speed of turbocharger radial compressors tends to reduce their range of operation, which is limited at low mass flow rate by the occurrence of surge. In order to extend the operability of turbochargers, compressor housings can be equipped with a passive surge control device such as a ''ported shroud.'' This specific casing treatment has been demonstrated to enhance the surge margin with minor negative impact on the compressor efficiency. However, the actual working mechanisms of the system remain not well understood. Hence, in order to optimize the design of the ported shroud, it is crucial to identify the dynamic flow changes induced by the implementation of the device to control instabilities. From the full dynamic survey of the compressor performance characteristics obtained with and without ported shroud, specific points of operation were selected to carry out planar flow visualization. At normal working, both standard and stereoscopic particle imaging velocimetry (PIV) measurements were performed to evaluate instantaneous and mean velocity flow fields at the inlet of the compressor. At incipient and full surge, phase-locked PIV measurements were added. As a result, satisfying characterization of the compressor instabilities was provided at different operational speeds. Combining transient pressure data and PIV measurements, the time evolution of the complex flow patterns occurring at surge was reconstructed and a better insight into the bypass mechanism was achieved. (orig.)

  9. PIV investigation of the flow induced by a passive surge control method in a radial compressor

    Science.gov (United States)

    Guillou, Erwann; Gancedo, Matthieu; Gutmark, Ephraim; Mohamed, Ashraf

    2012-09-01

    Due to recent emission regulations, the use of turbochargers for force induction of internal combustion engines has increased. Actually, the trend in diesel engines is to downsize the engine by use of turbochargers that operate at higher pressure ratios. Unfortunately, increasing the impeller rotational speed of turbocharger radial compressors tends to reduce their range of operation, which is limited at low mass flow rate by the occurrence of surge. In order to extend the operability of turbochargers, compressor housings can be equipped with a passive surge control device such as a "ported shroud." This specific casing treatment has been demonstrated to enhance the surge margin with minor negative impact on the compressor efficiency. However, the actual working mechanisms of the system remain not well understood. Hence, in order to optimize the design of the ported shroud, it is crucial to identify the dynamic flow changes induced by the implementation of the device to control instabilities. From the full dynamic survey of the compressor performance characteristics obtained with and without ported shroud, specific points of operation were selected to carry out planar flow visualization. At normal working, both standard and stereoscopic particle imaging velocimetry (PIV) measurements were performed to evaluate instantaneous and mean velocity flow fields at the inlet of the compressor. At incipient and full surge, phase-locked PIV measurements were added. As a result, satisfying characterization of the compressor instabilities was provided at different operational speeds. Combining transient pressure data and PIV measurements, the time evolution of the complex flow patterns occurring at surge was reconstructed and a better insight into the bypass mechanism was achieved.

  10. Controlled initial surge despite high drug fraction and high solubility.

    Science.gov (United States)

    Sarkar Das, Srilekha; Lucas, Anne D; Carlin, Alan S; Zheng, Jiwen; Patwardhan, Dinesh V; Saylor, David M

    2017-02-01

    Potential connections between release profiles and solvent evaporation rates alongside polymer chemistry were elucidated for the release of tetracycline hydrochloride from two different poly (d, l-lactide-co-glycolide) (PLGA) film matrices containing high drug fractions (50%, 30%, and 15%), and prepared at two distinct solvent evaporation rates. At highest tetracycline concentrations (50%), (i) the early release rates were ≤0.5 μg/min in all cases; (ii) release was linear from systems fabricated with lower lactic content and slower solvent evaporation rate and bimodal from systems fabricated with higher lactic content and faster evaporation rate; (iii) surface fractions covered by the drug were similar at both evaporation rates for 85:15 PLGA but very different for 50:50 PLGA, leading to unexpectedly reduced early release from 50:50 PLGA than from 85:15 PLGA when both the matrices were fabricated using a slower evaporation rate. These features remained unaffected in case of low drug concentration. Results suggested that during the formation of the drug-polymer microstructure, the combined effect of polymer chemistry and solvent evaporation rate sets apart the surface characteristics and the initial release profiles of systems containing high drug fraction, and an appropriate combination of these parameters may be utilized to control the early stage of drug release.

  11. Flow Characterization and Dynamic Analysis of a Radial Compressor with Passive Method of Surge Control

    Science.gov (United States)

    Guillou, Erwann

    Due to recent emission regulations, the use of turbochargers for force induction of internal combustion engines has increased. Actually, the trend in diesel engines is to downsize the engine by use of turbochargers that operate at higher pressure ratio. Unfortunately, increasing the rotational speed tends to reduce the turbocharger radial compressor range of operation which is limited at low mass flow rate by the occurrence of surge. In order to extent the operability of turbochargers, compressor housings can be equipped with a passive surge control device also known as ported shroud. This specific casing treatment has been demonstrated to enhance surge margin with minor negative impact on the compressor efficiency. However, the actual working mechanisms of the bypass system remain not well understood. In order to optimize the design of the ported shroud, it is then crucial to identify the dynamic flow changes induced by the implementation of the device to control instabilities. Experimental methods were used to assess the development of instabilities from stable, stall and eventually surge regimes of a ported shroud centrifugal compressor. Systematic comparison was conducted with the same compressor design without ported shroud. Hence, the full pressure dynamic survey of both compressors' performance characteristics converged toward two different and probably interrelated driving mechanisms to the development and/or propagation of unsteadiness within each compressor. One related the pressure disturbances at the compressor inlet, and notably the more apparent development of perturbations in the non-ported compressor impeller, whereas the other was attributed to the pressure distortions induced by the presence of the tongue in the asymmetric design of the compressor volute. Specific points of operation were selected to carry out planar flow measurements. At normal working, both standard and stereoscopic particle imaging velocimetry (PIV) measurements were performed

  12. Plant control to avoid surge development in the case of a pipe rupture in a direct cycle HTGR

    Energy Technology Data Exchange (ETDEWEB)

    Tauveron, Nicolas [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, 17 rue des Martyrs, 38100 Grenoble (France)], E-mail: nicolas.tauveron@cea.fr

    2008-11-15

    This work concerns the design and safety analysis of a direct cycle gas cooled reactor and is concentrated on surge occurrence, development, consequences, and control in case of a pipe rupture. To describe these phenomena, a specific turbomachine model is used. The dynamic behaviour of the compressor and different anti-surge configurations are tested. The tendencies (role of actuators, sensors, gain, bandwidth, plenum size) are in a good agreement with bibliographical data. The application to transient simulations of gas cooled nuclear reactors (hypothetical 10-in. break accident) shows that deep surge has to be avoided to protect compressor, heat exchangers and other pipes, whenever possible. The effects of using the bypass line are pointed out. Different strategies for instrumentation and control deployment are studied and different levels of efficiency are obtained. The complete avoidance of any surge oscillation would require the use of multiple very fast valves with a dedicated control command.

  13. Dispositional self-control: relationships with aerobic capacity and morning surge in blood pressure.

    Science.gov (United States)

    May, Ross W; Seibert, Gregory S; Sanchez-Gonzalez, Marcos A; Fitzgerald, Michael C; Fincham, Frank D

    2017-01-01

    The psychological, behavioral and psychosocial implications of self-control are well established, but relatively little is known about its implications for physical health. This study examined the association between self-control and two important indicators of cardiovascular risk: morning blood pressure surge (MBPS) and maximum oxygen consumption (VO 2max ). Undergraduate students (N = 78) completed a measure of dispositional self-control (Brief Self-Control Scale), participated in a 24-h ambulatory assessment of heart rate (HR) and blood pressure (BP), and completed the YMCA Cycle Ergometer Submaximal Test. Regression analyzes yielded a significant positive relationship between self-control and VO 2max . Results also indicated a significant negative association between self-control and MBPS, independent of average 24-h blood pressure and VO 2max scores. These findings expand our understanding of the relationship between dispositional self-control and MBPS. Study limitations and directions for future research are discussed.

  14. Monitoring of surge tanks in hydroelectric power plants using fuzzy control; Ueberwachung von Wasserschloessern in Wasserkraftwerken mit Fuzzy-Control

    Energy Technology Data Exchange (ETDEWEB)

    Lin, J.C.

    2000-07-01

    Surge tanks are used to reduce pressure variations caused by fluid transients in high-head hydroelectric power plants. Occasionally load increases have to be limited to prevent the surge tank from draining due to excessive demands of flow. A control concept based on fuzzy logic was developed for governing the load changes of hydroelectric power plants. In order to achieve an optimal control behaviour and simultaneously to avoid the draining of surge tanks, the speed of load increases is automatically adjusted by a fuzzy conclusion depending on the height and the gradient of the water level in the surge tank, the reservoir level and the sum of load increases. The hydroelectric power plant Achensee of Tiroler Wasserkraftwerke AG in Austria is taken as an example to demonstrate the characteristics of the control concept. In comparison with a conventional control concept, the operation of load increases using the fuzzy concept proves to be more flexible and unrestricted. (orig.) [German] Ein Wasserschloss dient zur Verminderung von Druckschwankungen im Wasserfuehrungssystem von Hochdruckanlagen. Gelegentlich muss man die Lastaufnahme so beschraenken, dass das Wasserschloss nicht durch uebermaessige Wasserentnahme leerlaeuft. Fuer die Leistungsregelung eines Wasserkraftwerks wurde ein Konzept entwickelt, das auf der Fuzzy-Control in Verbindung mit der klassischen Regelung beruht. Um ein optimales Regelverhalten zu erhalten und gleichzeitig das Leerlaufen des Wasserschlosses zu vermeiden, wird die Geschwindigkeit der Lastaufnahme in Abhaengigkeit von der Hoehenkote und dem Gradienten des Wasserschlosspegels, dem Pegel des Oberwassers und der Groesse der geforderten Lasterhoehung automatisch eingestellt. Die Untersuchung erfolgt am Beispiel des Achenseekraftwerkes der Tiroler Wasserkraftwerke AG, Oesterreich. Im Vergleich mit einer konventionellen Regelung ergibt sich mit dem Fuzzy-Konzept eine flexiblere und freizuegigere Lastaufnahme. (orig.)

  15. Controlled Ovarian Hyperstimulation with Intrauterine Insemination Is More Successful After r-hCG Administration Than Spontaneous LH Surge.

    Science.gov (United States)

    Taerk, Evan; Hughes, Edward; Greenberg, Cassandra; Neal, Michael; Amin, Shilpa; Faghih, Mehrnoosh; Karnis, Megan

    2017-01-01

    The purpose of this study was to evaluate whether clinical pregnancy rate is affected by timing intrauterine insemination (IUI) according to serum LH surge, r-hCG trigger, or a combination of LH surge and r-hCG trigger in controlled ovarian hyperstimulation (COH) cycles for patients with a variety of infertility etiologies. The last 365 consecutive COH-IUI cycles performed at ONE Fertility Burlington in 2014 were reviewed and categorized according to method of IUI timing. Associations between categorical variables were analyzed using a combination of Chi-square and Fisher's Exact tests, and between continuous variables using independent sample t-tests and logistic regression to a level of significance of psurge: 18.2% vs. 5.8%, p=0.012. Patients in whom r-hCG was administered concomitantly with a serum LH surge had a higher clinical pregnancy than the r-hCG trigger group (30.8% vs. 18.2%, p=0.004) and LH surge group (30.8% vs. 5.8%, psurge group (21.7% vs. 2.1%, p=0.01). In subfertile couples undergoing COH-IUI, r-hCG administration was associated with an increased clinical pregnancy rate compared with spontaneous serum LH surge. When r-hCG was administered concomitantly with a serum LH surge, this benefit was amplified. The effect appears to be of particular importance in r-FSH-medicated cycles.

  16. Short loop feedback control of the estrogen-induced luteinizing hormone surge in pigs.

    Science.gov (United States)

    Ziecik, A J; Britt, J H; Esbenshade, K L

    1988-04-01

    This study examines whether hCG will block the estradiol-induced LH surge in ovariectomized gilts. Twenty post-puberal cross-bred gilts were ovariectomized at 6-7 months of age. Approximately 2 months later, the experiment was conducted, and all gilts were given estradiol benzoate (EB; 10 micrograms/kg, im) at 0 h. Controls (n = 6) received im saline 24 and 48 h after EB. Two groups of gilts received 2000 IU hCG im, at 24 h (hCG24; n = 5) or 48 h (hCG48; n = 5) after EB. The fourth group (n = 4) received hCG at 48 h and was then given iv a LHRH agonist (des-Gly10, [D-Ala6]LHRH ethylamide) in 100-ng boluses hourly from 54-96 h after EB. Blood samples for determination of LH and FSH were collected every 6 h from 0-96 h. In controls, EB alone suppressed LH from 3.9 +/- 1.9 ng/ml at 0 h to 1.0 +/- 0.2 during 6-48 h (negative feedback), but LH then increased to 4.5 +/- 0.5 between 54 and 96 h (positive feedback), with the peak of the surge (6.7 +/- 1.6) occurring at 72 h. Treatment with hCG did not alter LH during the negative feedback phase (1.1 +/- 0.1 and 1.0 +/- 0.1 for hCG24 and hCG48, respectively). However, there was no LH surge in gilts given hCG at 24 or 48 h (2.4 +/- 0.2 and 2.2 +/- 0.1 form 54-96 h; P less than 0.05). Hourly injections of the LHRH agonist evoked a surge in LH (8.3 +/- 1.3) and maintained elevated LH (4.5 +/- 0.6) between 54 and 96 h, similar (P greater than 0.05) to values for controls. Generally, FSH in gilts given hCG followed the same pattern as LH secretion during the negative feedback stage; however, due to randomization, means for the period from 0-48 h for gilts treated with hCG 24 or 48 h after EB were lower (P less than 0.05) than for controls or gilts given LHRH agonist (62.2 +/- 2.8 and 63.0 +/- 2.7 vs. 79.3 +/- 3.2 and 93.3 +/- 4.2 ng/ml, respectively). During the positive feedback phase (54-96 h), FSH was lower in gilts given hCG (hCG24, 63.4 +/- 2.3; hCG48, 67.3 +/- 2.0) than in controls (86.0 +/- 4.0), but in gilts given LHRH

  17. Active Flow Control in a Radial Vaned Diffuser for Surge Margin Improvement: A Multislot Suction Strategy

    Directory of Open Access Journals (Sweden)

    Aurélien Marsan

    2017-01-01

    Full Text Available This work is the final step of a research project that aims at evaluating the possibility of delaying the surge of a centrifugal compressor stage using a boundary-layer suction technique. It is based on Reynolds-Averaged Navier-Stokes numerical simulations. Boundary-layer suction is applied within the radial vaned diffuser. Previous work has shown the necessity to take into account the unsteady behavior of the flow when designing the active flow control technique. In this paper, a multislot strategy is designed according to the characteristics of the unsteady pressure field. Its implementation results in a significant increase of the stable operating range predicted by the unsteady RANS numerical model. A hub-corner separation still exists further downstream in the diffuser passage but does not compromise the stability of the compressor stage.

  18. A circuit scheme to control current surge for RFID-NVM pumps

    Energy Technology Data Exchange (ETDEWEB)

    Li Ming; Kang Jinfeng; Wang Yangyuan [Institute of Microelectronics, Peking University, Beijing 100871 (China); Yang Liwu, E-mail: prettynecess@163.co [Semiconductor Manufacturing International Corporation, Shanghai 201203 (China)

    2010-02-15

    This paper presents a new circuit scheme to control the current surge in the boosting phase of an radio frequency idenfication-nonvolative memory pump. By introducing a circuit block consisting of a current reference and a current mirror, the new circuit scheme can keep the period-average current of the pump constantly below the desired level, for example, 2.5 {mu}A. Therefore, it can prevent the rectified supply of the RFID tag IC from collapsing in the boosting phase of the pump. The presented scheme could effectively reduce the voltage drop on the rectified supply from more than 50% to even zero, but could cost less area. Moreover, an analytical expression to calculate the boosting time of a pump in the new scheme is developed. (semiconductor integrated circuits)

  19. Preliminary Analysis of an Oscillating Surge Wave Energy Converter with Controlled Geometry: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan; Lawson, Michael; Yu, Yi-Hsiang; Wright, Alan

    2015-09-09

    The aim of this paper is to present a novel wave energy converter device concept that is being developed at the National Renewable Energy Laboratory. The proposed concept combines an oscillating surge wave energy converter with active control surfaces. These active control surfaces allow for the device geometry to be altered, which leads to changes in the hydrodynamic properties. The device geometry will be controlled on a sea state time scale and combined with wave-to-wave power-take-off control to maximize power capture, increase capacity factor, and reduce design loads. The paper begins with a traditional linear frequency domain analysis of the device performance. Performance sensitivity to foil pitch angle, the number of activated foils, and foil cross section geometry is presented to illustrate the current design decisions; however, it is understood from previous studies that modeling of current oscillating wave energy converter designs requires the consideration of nonlinear hydrodynamics and viscous drag forces. In response, a nonlinear model is presented that highlights the shortcomings of the linear frequency domain analysis and increases the precision in predicted performance.

  20. Piece-wise mixed integer programming for optimal sizing of surge control devices in water distribution systems

    Science.gov (United States)

    Skulovich, Olya; Bent, Russell; Judi, David; Perelman, Lina Sela; Ostfeld, Avi

    2015-06-01

    Despite their potential catastrophic impact, transients are often ignored or presented ad hoc when designing water distribution systems. To address this problem, we introduce a new piece-wise function fitting model that is integrated with mixed integer programming to optimally place and size surge tanks for transient control. The key features of the algorithm are a model-driven discretization of the search space, a linear approximation nonsmooth system response surface to transients, and a mixed integer linear programming optimization. Results indicate that high quality solutions can be obtained within a reasonable number of function evaluations and demonstrate the computational effectiveness of the approach through two case studies. The work investigates one type of surge control devices (closed surge tank) for a specified set of transient events. The performance of the algorithm relies on the assumption that there exists a smooth relationship between the objective function and tank size. Results indicate the potential of the approach for the optimal surge control design in water systems.

  1. Damage to ITS, traffic control and roadway lighting equipment from transient surge and lightning strikes.

    Science.gov (United States)

    2016-11-01

    The goal of this project was to collect the knowledge needed for the FDOT to either confirm or : improve the adequacy of the FDOTs existing minimum standards for lightning/surge protection, : including devices used and installation procedures. The...

  2. A Simple Graphical Method for Quantification of Disaster Management Surge Capacity Using Computer Simulation and Process-control Tools.

    Science.gov (United States)

    Franc, Jeffrey Michael; Ingrassia, Pier Luigi; Verde, Manuela; Colombo, Davide; Della Corte, Francesco

    2015-02-01

    Surge capacity, or the ability to manage an extraordinary volume of patients, is fundamental for hospital management of mass-casualty incidents. However, quantification of surge capacity is difficult and no universal standard for its measurement has emerged, nor has a standardized statistical method been advocated. As mass-casualty incidents are rare, simulation may represent a viable alternative to measure surge capacity. Hypothesis/Problem The objective of the current study was to develop a statistical method for the quantification of surge capacity using a combination of computer simulation and simple process-control statistical tools. Length-of-stay (LOS) and patient volume (PV) were used as metrics. The use of this method was then demonstrated on a subsequent computer simulation of an emergency department (ED) response to a mass-casualty incident. In the derivation phase, 357 participants in five countries performed 62 computer simulations of an ED response to a mass-casualty incident. Benchmarks for ED response were derived from these simulations, including LOS and PV metrics for triage, bed assignment, physician assessment, and disposition. In the application phase, 13 students of the European Master in Disaster Medicine (EMDM) program completed the same simulation scenario, and the results were compared to the standards obtained in the derivation phase. Patient-volume metrics included number of patients to be triaged, assigned to rooms, assessed by a physician, and disposed. Length-of-stay metrics included median time to triage, room assignment, physician assessment, and disposition. Simple graphical methods were used to compare the application phase group to the derived benchmarks using process-control statistical tools. The group in the application phase failed to meet the indicated standard for LOS from admission to disposition decision. This study demonstrates how simulation software can be used to derive values for objective benchmarks of ED surge

  3. Application of Fuzzy-Logic Controller and Neural Networks Controller in Gas Turbine Speed Control and Overheating Control and Surge Control on Transient Performance

    Science.gov (United States)

    Torghabeh, A. A.; Tousi, A. M.

    2007-08-01

    This paper presents Fuzzy Logic and Neural Networks approach to Gas Turbine Fuel schedules. Modeling of non-linear system using feed forward artificial Neural Networks using data generated by a simulated gas turbine program is introduced. Two artificial Neural Networks are used , depicting the non-linear relationship between gas generator speed and fuel flow, and turbine inlet temperature and fuel flow respectively . Off-line fast simulations are used for engine controller design for turbojet engine based on repeated simulation. The Mamdani and Sugeno models are used to expression the Fuzzy system . The linguistic Fuzzy rules and membership functions are presents and a Fuzzy controller will be proposed to provide an Open-Loop control for the gas turbine engine during acceleration and deceleration . MATLAB Simulink was used to apply the Fuzzy Logic and Neural Networks analysis. Both systems were able to approximate functions characterizing the acceleration and deceleration schedules . Surge and Flame-out avoidance during acceleration and deceleration phases are then checked . Turbine Inlet Temperature also checked and controls by Neural Networks controller. This Fuzzy Logic and Neural Network Controllers output results are validated and evaluated by GSP software . The validation results are used to evaluate the generalization ability of these artificial Neural Networks and Fuzzy Logic controllers.

  4. Storm surge variational assimilation model

    Directory of Open Access Journals (Sweden)

    Shi-li HUANG

    2010-06-01

    Full Text Available To eliminate errors caused by uncertainty of parameters and further improve capability of storm surge forecasting, the variational data assimilation method is applied to the storm surge model based on unstructured grid with high spatial resolution. The method can effectively improve the forecasting accuracy of storm surge induced by typhoon through controlling wind drag force coefficient parameter. The model is first theoretically validated with synthetic data. Then, the real storm surge process induced by the TC 0515 typhoon is forecasted by the variational data assimilation model, and results show the feasibility of practical application.

  5. Nonlinear dynamic analysis and robust controller design for Francis hydraulic turbine regulating system with a straight-tube surge tank

    Science.gov (United States)

    Liang, Ji; Yuan, Xiaohui; Yuan, Yanbin; Chen, Zhihuan; Li, Yuanzheng

    2017-02-01

    The safety and stability of hydraulic turbine regulating system (HTRS) in hydropower plants become increasingly important since the rapid development and the broad application of hydro energy technology. In this paper, a novel mathematical model of Francis hydraulic turbine regulating system with a straight-tube surge tank based on a few state-space equations is introduced to study the dynamic behaviors of the HTRS system, where the existence of possible unstable oscillations of this model is studied extensively and presented in the forms of the bifurcation diagram, time waveform plot, phase trajectories, and power spectrum. To eliminate these undesirable behaviors, a specified fuzzy sliding mode controller is designed. In this hybrid controller, the sliding mode control law makes full use of the proposed model to guarantee the robust control in the presence of system uncertainties, while the fuzzy system is applied to approximate the proper gains of the switching control in sliding mode technique to reduce the chattering effect, and particle swarm optimization is developed to search the optimal gains of the controller. Numerical simulations are presented to verify the effectiveness of the designed controller, and the results show that the performances of the nonlinear HTRS system assisted with the proposed controller is much better than that with the commonly used optimal PID controller.

  6. Circadian Control of the Estrogenic Circuits Regulating GnRH Secretion and the Preovulatory Luteinizing Hormone Surge

    Directory of Open Access Journals (Sweden)

    Lance J Kriegsfeld

    2012-05-01

    Full Text Available Female reproduction requires the precise temporal organization of interacting, estradiol-sensitive neural circuits that converge to optimally drive hypothalamo-pituitary-gonadal (HPG axis functioning. In mammals, the master circadian pacemaker in the suprachaismatic nucleus (SCN of the anterior hypothalamus coordinates reproductively-relevant neuroendocrine events necessary to maximize reproductive success. Likewise, in species where periods of fertility are brief, circadian oversight of reproductive function ensures that estradiol-dependent increases in sexual motivation coincide with ovulation. Across species, including humans, disruptions to circadian timing (e.g., through rotating shift work, night shift work, poor sleep hygiene lead to pronounced deficits in ovulation and fecundity. Despite the well-established roles for the circadian system in female reproductive functioning, the specific neural circuits and neurochemical mediators underlying these interactions are not fully understood. Most work to date has focused on the direct and indirect communication from the SCN to the GnRH system in control of the preovulatory LH surge. However, the same clock genes underlying circadian rhythms at the cellular level in SCN cells are also common to target cell populations of the SCN, including the GnRH neuronal network. Exploring the means by which the master clock synergizes with subordinate clocks in GnRH cells and its upstream modulatory systems represents an exciting opportunity to further understand the role of endogenous timing systems in female reproduction. Herein we provide an overview of the state of knowledge regarding interactions between the circadian timing system and estradiol-sensitive neural circuits driving GnRH secretion and the preovulatory LH surge.

  7. Validation of a surge model by full scale testing

    NARCIS (Netherlands)

    Slot, H.J.; Meulendijks, D.; Smeulers, J.P.M.

    2009-01-01

    Surge of turbo compressors can cause large stepwise changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. Surge is usually avoided by an anti surge controller (ASC). However, in spite of the ASC surge cycles may

  8. Validation of a surge model by full scale testing

    NARCIS (Netherlands)

    Smeulers, J.P.M.; Slot, H.J.; Meulendijks, D.

    2011-01-01

    Surge of turbo compressors can cause large stepwise changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. Surge is usually avoided by an anti surge controller (ASC). However, in spite of the ASC surge cycles may

  9. Association between glycemic control and morning blood surge with vascular endothelial dysfunction in type 2 diabetes mellitus patients

    Directory of Open Access Journals (Sweden)

    Rama Kumari Nuthalapati

    2016-01-01

    Full Text Available Objective: Morning blood pressure surge (MBPS is an independent predictor of cardiovascular events. However, little is known about the association between glycemic control and MBPS, and its effect on vascular injury in patients with type 2 diabetes mellitus (T2DM. The current study examined the association between glycemic control and MBPS and the involvement of MBPS in the development of vascular dysfunction in T2DM patients. Materials and Methods: One hundred and twenty-two consecutive T2DM outpatients from the Department of Cardiology and Endocrinology were enrolled in this study. We did MBPS in T2DM patients, 85 (male (69.7% patients and 37 (female patients (30.3%; mean age 60.1 ± 9.39; (n = 122 using 24 h ambulatory blood pressure monitoring and assessed vascular function by brachial artery flow-mediated dilation (FMD and nitroglycerin-mediated dilation (NMD. Results: The correlation between MBPS and various clinical variables were examined by single regression analysis in all subjects. MBPS showed significant and positive correlation with pulse rate (P = 0.01, fasting blood sugar (P = 0.002, and postprandial blood sugar (P = 0.05. To further confirm the association of insulin resistance (IR with MBPS in T2DM patients, we examined the correlation between homeostasis model assessment-IR (HOMA-IR, an established marker of IR and MBPS in diabetic (DM patients who were not taking insulin no significant association with MBPS in T2DM patients (P = 0.41, angiotensin-converting enzyme/angiotensin receptor blocker (P = 0.07. We examined the relationship between MBPS and vascular injury by measuring endothelium-dependent FMD and endothelium-independent NMD in T2DM patients. Among the various traditional risk factors for atherosclerosis such as DM duration (P = 0.04, platelet reactivity (P = 0.04 and morning surge (P = 0.002 emerged as significant factors. HOMA-IR was a negative correlation with FMD. Conclusions: The current study demonstrated that

  10. Prognostic Value of Nondipping and Morning Surge in Elderly Treated Hypertensive Patients With Controlled Ambulatory Blood Pressure.

    Science.gov (United States)

    Pierdomenico, Sante D; Pierdomenico, Anna M; Coccina, Francesca; Lapenna, Domenico; Porreca, Ettore

    2017-02-01

    The independent prognostic significance of nondipping and morning surge (MS) of blood pressure (BP) in treated hypertensive patients with controlled ambulatory BP is not yet clear. We investigated the association between the aforesaid ambulatory BP parameters and cardiovascular risk in elderly treated hypertensive patients with normal achieved ambulatory BP. The occurrence of a composite end-point (stroke, coronary events, heart failure, and peripheral revascularization) was evaluated in 391 elderly treated hypertensive patients (age range 60-90 years) with controlled ambulatory BP (both daytime BP 23 mm Hg) and nondippers. During the follow-up (9.3 ± 4.6 years, range 0.5-20 years), 76 events occurred. The event-rate was 2.09 per 100 patient-years. After adjustment for age, gender, left ventricular (LV) hypertrophy, asymptomatic LV systolic dysfunction at baseline and left atrial enlargement, dippers with high MS (hazard ratio 2.45, 95% confidence interval 1.27-4.73, P = 0.007) and nondippers (hazard ratio 2.04, 95% confidence interval 1.18-3.53, P = 0.01) were at higher cardiovascular risk than dippers with normal MS. In elderly treated hypertensive patients with normal achieved ambulatory BP, dippers with high MS and nondippers are at increased cardiovascular risk. © American Journal of Hypertension, Ltd 2016. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Pressure surge attenuator

    Science.gov (United States)

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  12. Circadian control of kisspeptin and a gated GnRH response mediate the preovulatory luteinizing hormone surge

    DEFF Research Database (Denmark)

    Williams, Wilbur P; Jarjisian, Stephan G; Mikkelsen, Jens D

    2011-01-01

    In spontaneously ovulating rodents, the preovulatory LH surge is initiated on the day of proestrus by a timed, stimulatory signal originating from the circadian clock in the suprachiasmatic nucleus (SCN). The present studies explored whether kisspeptin is part of the essential neural circuit link...

  13. [Western area surge for controlling Ebola hemorrhagic fever outbreak in Sierra Leone and evaluation of its effect].

    Science.gov (United States)

    Chen, Yong; Wu, Dan; Zhang, Wenyi; Chen, Zeliang; Chang, Guohui; Tian, Shuguang; Yang, Ruifu; Liu, Chao

    2015-10-01

    To investigate the Western Area Surge (WAS) program in the Ebola outbreak of Sierra Leone, and to analyze its implementing effect. The subject of this study was 3,813 laboratory confirmed Ebola hemorrhagic fever (EHF) cases reported in Sierra Leone from November 19, 2014 through January 27, 2015, a period before and after the implementation of the WAS program. To analyze and make conclusions according to the working experience of China Mobile Laboratory Reponses Team in the fight of Ebola outbreak, using WHO published EHF case definition to make diagnosis and compare the number of bed numbers, confirmed EHF cases, samples tested, and positive rates before and after implementation of WAS program. From the implementation of WAS program on 17th December 2014 to half a month later, the total numbers of Ebola holding and treatment centers increased from 640 to 960, six additional laboratories were established. On January, 2015, another two laboratories from America and The Netherlands were established. The numbers of samples tested one month before and after WAS program were 7,891 and 9,783, respectively, with an increase of 24.0 percent, while the positive rate of Ebola virus decreased from 22.2% (1,752/7,891) to 11.0% (1,077/9,783). The positive rate of blood samples decreased from 39.6% (248/626) in the month before WAS program to 27.4% (131/478) (χ2=17.93, P<0.001) in the mother after WAS program, the positive rate of blood samples 22.7% (103/454) to 10% (62/609) (χ2=31.03, P<0.001), accordingly. After 3 weeks of WAS program, in addition to Western Area, another four hotspots in Sierra Leone had also reported a significant decrease of the numbers of confirmed EVD cases. Forty-two days after implementation of WAS program, the daily number of laboratory confirmed EHF cases decreased from 63 to 10. WAS program played a vital role in controlling the EHF outbreak rapidly in Sierra Leone. It could also provide guidance for the control similar large infectious diseases

  14. Validation of a surge model by full scale testing

    NARCIS (Netherlands)

    Smeulers, J.P.M.; Gonzalez Díez, N.; Slot, H.J.

    2012-01-01

    Surge of turbo compressors can cause large almost step like changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. In spite of an anti-surge controller (ASC), at extreme events surge cycles may occur. In order to

  15. 3D-FE Modeling of 316 SS under Strain-Controlled Fatigue Loading and CFD Simulation of PWR Surge Line

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish [Argonne National Lab. (ANL), Argonne, IL (United States); Barua, Bipul [Argonne National Lab. (ANL), Argonne, IL (United States); Listwan, Joseph [Argonne National Lab. (ANL), Argonne, IL (United States); Majumdar, Saurin [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, Ken [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-03-01

    In financial year 2017, we are focusing on developing a mechanistic fatigue model of surge line pipes for pressurized water reactors (PWRs). To that end, we plan to perform the following tasks: (1) conduct stress- and strain-controlled fatigue testing of surge-line base metal such as 316 stainless steel (SS) under constant, variable, and random fatigue loading, (2) develop cyclic plasticity material models of 316 SS, (3) develop one-dimensional (1D) analytical or closed-form model to validate the material models and to understand the mechanics associated with 316 SS cyclic hardening and/or softening, (4) develop three-dimensional (3D) finite element (FE) models with implementation of evolutionary cyclic plasticity, and (5) develop computational fluid dynamics (CFD) model for thermal stratification, thermal-mechanical stress, and fatigue of example reactor components, such as a PWR surge line under plant heat-up, cool-down, and normal operation with/without grid-load-following. This semi-annual progress report presents the work completed on the above tasks for a 316 SS laboratory-scale specimen subjected to strain-controlled cyclic loading with constant, variable, and random amplitude. This is the first time that the accurate 3D-FE modeling of the specimen for its entire fatigue life, including the hardening and softening behavior, has been achieved. We anticipate that this work will pave the way for the development of a fully mechanistic-computer model that can be used for fatigue evaluation of safety-critical metallic components, which are traditionally evaluated by heavy reliance on time-consuming and costly test-based approaches. This basic research will not only help the nuclear reactor industry for fatigue evaluation of reactor components in a cost effective and less time-consuming way, but will also help other safety-related industries, such as aerospace, which is heavily dependent on test-based approaches, where a single full-scale fatigue test can cost

  16. Storm surge climatology report

    OpenAIRE

    Horsburgh, Kevin; Williams, Joanne; Cussack, Caroline

    2017-01-01

    Any increase in flood frequency or severity due to sea level rise or changes in storminess would adversely impact society. It is crucial to understand the physical drivers of extreme storm surges to have confidence in the datasets used for extreme sea level statistics. We will refine and improve methods to the estimation of extreme sea levels around Europe and more widely. We will do so by developing a comprehensive world picture of storm surge distribution (including extremes) for both tropi...

  17. Storm Surge Predictability

    Science.gov (United States)

    Morss, R. E.; Fossell, K.; Ahijevych, D.; Davis, C. A.; Snyder, C.

    2016-12-01

    Storm surge is one of the most dangerous hazards of hurricanes; it results in devastating flooding and billions of dollars in damage to coastal regions and is one of the primary hurricane threats for loss of life. As such it is of great interest to better understand the probability of significant storm surge occurrence and the potential extent of impact at longer lead times to give emergency managers adequate time to plan for necessary evacuation and protective measures. This work aims to quantify the practical predictability of storm surge at various lead times and the sensitivity of the storm surge to storm parameters such as track, strength, size, and translation speed. This study also draws a distinction between inundation of a fixed region and inundation following the storm landfall location as the track varies. The latter is not usually considered, but is important for identifying particularly dangerous scenarios within the envelope of possible realizations. We quantify the predictability of storm surge from both the local and storm-following perspectives. The ADCIRC model is used to produce an ensemble of storm surge simulations. The ensemble is generated in an idealized context where the model is driven by best track data and perturbations from the best track (e.g. storm track, maximum wind, storm speed, and storm size). Inundation metrics are computed for both storm-following inundation and location-based inundation to better understand the predictive nature. While the magnitude of maximum inundation at a point is often emphasized in storm surge prediction studies, this study focuses on integrated metrics such as inundation volume and spatial extent of inundation along the coast and inland. Results will be presented from simulations of Hurricane Ike, Hurricane Charley, and a hypothetical storm that combines the size and intensity of Hurricane Charley over the track of Hurricane Ike, to demonstrate the sensitivity of inundation to a certain storm of certain

  18. Control Effect of a Large Geological Discontinuity on the Seismic Response and Stability of Underground Rock Caverns: A Case Study of the Baihetan #1 Surge Chamber

    Science.gov (United States)

    Cui, Zhen; Sheng, Qian; Leng, Xianlun

    2016-06-01

    In this paper, the seismic stability of the #1 surge chamber of the Baihetan hydropower plant, which is influenced by a large dominating geological discontinuity [the interlayer shear weakness zone (ISWZ) C2)], is studied. An advanced, nonlinear, continuously yielding (CY) model was adopted to describe the complex mechanical properties of ISWZ C2. This model considers a power function type, normal stress dependent behavior and the progressive damage that occurred during shear tests. The applicability of the CY model is proved via a comparison with field test results and the theoretical solution. Verification work was conducted in 3DEC code to show that the 3DEC software is suitable for implementing this model. Three ground motion waveforms were utilized to conduct a seismic analysis of the #1 surge chamber after a special response spectrum matching process. The seismic analysis confirmed the control effect of ISWZ C2 on the seismic stability of the cavern. The majority of the cavern's seismic displacement consists of elastic body movement, while the plastic deformation is relatively limited. Further, most of the deformations were caused by the contact deformation of C2. For the contact deformation of C2, the magnitude of permanent shear deformation is larger than that of the normal deformation. The magnitude of permanent shear deformation is more notable along the strike direction of C2, and the permanent normal displacement n of C2 mainly occurs along the dip direction of C2. Finally, the seismic stability of the cavern is assessed via the overload method. The seismic safety factor of the cavern is approximately 2-3.

  19. Deep FIFO Surge Buffer

    Science.gov (United States)

    Temple, Gerald; Siegel, Marc; Amitai, Zwie

    1991-01-01

    First-in/first-out (FIFO) temporarily stores short surges of data generated by data-acquisition system at excessively high rate and releases data at lower rate suitable for processing by computer. Size and complexity reduced while capacity enhanced by use of newly developed, sophisticated integrated circuits and by "byte-folding" scheme doubling effective depth and data rate.

  20. Positive feedback stabilization of centrifugal compressor surge

    NARCIS (Netherlands)

    Willems, Frank; Heemels, W.P.M.H.; de Jager, Bram; Stoorvogel, Antonie Arij

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  1. Demand surge following earthquakes

    Science.gov (United States)

    Olsen, Anna H.

    2012-01-01

    Demand surge is understood to be a socio-economic phenomenon where repair costs for the same damage are higher after large- versus small-scale natural disasters. It has reportedly increased monetary losses by 20 to 50%. In previous work, a model for the increased costs of reconstruction labor and materials was developed for hurricanes in the Southeast United States. The model showed that labor cost increases, rather than the material component, drove the total repair cost increases, and this finding could be extended to earthquakes. A study of past large-scale disasters suggested that there may be additional explanations for demand surge. Two such explanations specific to earthquakes are the exclusion of insurance coverage for earthquake damage and possible concurrent causation of damage from an earthquake followed by fire or tsunami. Additional research into these aspects might provide a better explanation for increased monetary losses after large- vs. small-scale earthquakes.

  2. Control of the Amplitude in a Surging Balling Drum Circuit, a New Approach to an Old Problem

    Directory of Open Access Journals (Sweden)

    Knut Rapp

    2003-10-01

    Full Text Available In this paper we suggest a new method for controlling the balling drums used in the iron ore industry. We suggest that a cluster of drums are controlled collectively rather than individually. Further, we investigate the possibility of using an extended Kalman filter for estimating the amplitude and frequency of the oscillations in such drums. The filters thresholding point is identified, and the area for which the filter is usable is given. Finally a simulation of the proposed control scheme, based on a simple nonlinear model, is presented.

  3. Decreased nocturnal surge of thyrotropin in nonthyroidal illness

    NARCIS (Netherlands)

    Romijn, J. A.; Wiersinga, W. M.

    1990-01-01

    To evaluate the regulation of TSH secretion in nonthyroidal illness (NTI) we studied the nocturnal TSH surge in 11 healthy controls and 26 NTI patients; none of the patients was on medication known to interfere with TSH secretion. The presence of a nocturnal TSH surge was defined as a mean nighttime

  4. Effect of azilsartan versus candesartan on morning blood pressure surges in Japanese patients with essential hypertension.

    Science.gov (United States)

    Rakugi, Hiromi; Kario, Kazuomi; Enya, Kazuaki; Sugiura, Kenkichi; Ikeda, Yoshinori

    2014-06-01

    Morning blood pressure (BP) surge is reported as a risk factor for cardiovascular events and end-organ damage independent of the 24-h BP level. Controlling morning BP surge is therefore important to help prevent onset of cardiovascular disease. We compared the efficacy of azilsartan and candesartan in controlling morning systolic BP (SBP) surges by analyzing relevant ambulatory BP monitoring data in patients with/without baseline BP surges. As part of a 16-week randomized, double-blind study of azilsartan (20-40 mg once daily) and candesartan (8-12 mg once daily) in Japanese patients with essential hypertension, an exploratory analysis was carried out using ambulatory BP monitoring at baseline and week 14. The effects of study drugs on morning BP surges, including sleep trough surge (early morning SBP minus the lowest night-time SBP) and prewaking surge (early morning SBP minus SBP before awakening), were evaluated. Patients with sleep trough surge of at least 35 mmHg were defined by the presence of a morning BP surge (the 'surge group'). Sleep trough surge and prewaking surge data were available at both baseline and week 14 in 548 patients, 147 of whom (azilsartan 76; candesartan 71) had a baseline morning BP surge. In surge group patients, azilsartan significantly reduced both the sleep trough surge and the prewaking surge at week 14 compared with candesartan (least squares means of the between-group differences -5.8 mmHg, P=0.0395; and -5.7 mmHg, P=0.0228, respectively). Once-daily azilsartan improved sleep trough surge and prewaking surge to a greater extent than candesartan in Japanese patients with grade I-II essential hypertension.

  5. SURGE: Smart Ultrasound Remote Guidance Experiment

    Science.gov (United States)

    Peterson, Sean

    2009-01-01

    Exploration-class missions lead to longer communication delays with mission control. May not always have communication capability to stream real-time ultrasound images. SURGE explores use of a "just-in-time" learning tool, called OPEL = On-Board Proficiency Enhancer Light as an aid to a hypothetical crew medical officer working autonomously.

  6. Surge uma nova revista

    OpenAIRE

    Lima, Samuel do Carmo; Universidade Federal de Uberlândia

    2006-01-01

    Surge uma nova revista científica na Geografia, Hygeia - Revista Brasileira de Geografia Médica e da Saúde foi concebida no VI Encontro Nacional ANPEGE, em Fortaleza (CE), em outubro de 2005. Em uma sessão coordenada sobre “A Geografia da Saúde nos Programas de Pós-graduação em Geografia do Brasil�?, a idéia da revista foi apresentada como uma ousadia, mas imediatamente recebeu manifestações de apoio e a ousadia virou um sonho. A verdade é que esta área da Geografia vem crescendo muito rapida...

  7. Skill and Australia's productivity surge

    OpenAIRE

    Paula Barnes; Sharon Kennard

    2002-01-01

    Skill and Australia’s Productivity Surge examines the changing demand for skills and the effect of increased skill on productivity growth. It finds that Australia’s productivity surge post 1993-94 was mainly due to factors other than the increase in the skill of the workforce.

  8. Effect of turbine-operating regime and adjustment of automated control system on stability and critical area of surge tanks at HPP

    Energy Technology Data Exchange (ETDEWEB)

    Murav' ev, O. A. [Moscow State Civil-Engineering University (Russian Federation)

    2011-05-15

    Materials of the works of several authors who have investigated the effect of turbine-operating regime on the stability of HPP with surge tanks are presented. Anumber of new results are obtained. Analytical relationships that can be used in stability calculations for a number of coefficients are compared with a large amount of actual data.

  9. Dose-finding study of Leuplin depot for prevention of premature luteinizing hormone surge during controlled ovarian stimulation: a pilot study in intrauterine insemination treatment

    Directory of Open Access Journals (Sweden)

    Heng-Ju Chen

    2016-04-01

    Conclusion: The 1/4 dose of Leuplin depot is the minimal effective dose to prevent premature LH surge. Further trial is worthwhile to compare the reducing dose Leuplin depot and daily low-dose leuprolide in in vitro fertilization (IVF programs.

  10. Exercising Tactically for Taming Postmeal Glucose Surges

    Directory of Open Access Journals (Sweden)

    Elsamma Chacko

    2016-01-01

    Full Text Available This review seeks to synthesize data on the timing, intensity, and duration of exercise found scattered over some 39 studies spanning 3+ decades into optimal exercise conditions for controlling postmeal glucose surges. The results show that a light aerobic exercise for 60 min or moderate activity for 20–30 min starting 30 min after meal can efficiently blunt the glucose surge, with minimal risk of hypoglycemia. Exercising at other times could lead to glucose elevation caused by counterregulation. Adding a short bout of resistance exercise of moderate intensity (60%–80%  VO2max to the aerobic activity, 2 or 3 times a week as recommended by the current guidelines, may also help with the lowering of glucose surges. On the other hand, high-intensity exercise (>80%  VO2max causes wide glucose fluctuations and its feasibility and efficacy for glucose regulation remain to be ascertained. Promoting the kind of physical activity that best counters postmeal hyperglycemia is crucial because hundreds of millions of diabetes patients living in developing countries and in the pockets of poverty in the West must do without medicines, supplies, and special diets. Physical activity is the one tool they may readily utilize to tame postmeal glucose surges. Exercising in this manner does not violate any of the current guidelines, which encourage exercise any time.

  11. Roles of estradiol and gonadotropin-releasing hormone in controlling negative and positive feedback associated with the luteinizing hormone surge in ovariectomized pigs.

    Science.gov (United States)

    Britt, J H; Esbenshade, K L; Ziecik, A J

    1991-09-01

    Ovariectomized gilts (n = 63) were given estradiol benzoate (estradiol), antiserum to neutralize endogenous GnRH, and pulses of a GnRH agonist (GnRH-A) to stimulate release of LH. GnRH-A was given as 200-ng pulses hourly from 0 to 54 h and as 100- or 200-ng pulses every 30 or 60 min from 54 to 96 h after estradiol. Estradiol alone suppressed LH from 6 to 54 h and elicited an LH surge that peaked at 72 h. When GnRH-A was given every 30-60 min from 0 to 96 h, estradiol suppressed LH for 6-12 h, but then LH returned to pre-estradiol concentrations. When pulses of GnRH-A were given only between 54 and 96 h after estradiol, the surge of LH was related positively to dose and frequency of GnRH-A. We conclude that 1) estrogen acts at the hypothalamus to inhibit release of GnRH for 54 h and then causes a synchronous release of GnRH; 2) estrogen acts at the pituitary to block its response to GnRH for 6-12 h and enhances the accumulation of releasable LH; and 3) magnitude of the LH surge is dependent on the amount of GnRH stimulation.

  12. Medical surge capacity: workshop summary

    National Research Council Canada - National Science Library

    Altevogt, Bruce M

    2010-01-01

    "During natural disasters, disease pandemics, terrorist attacks, and other public health emergencies, the health system must be prepared to accommodate a surge in the number of individuals seeking medical help...

  13. 7 CFR 58.218 - Surge tanks.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Surge tanks. 58.218 Section 58.218 Agriculture....218 Surge tanks. If surge tanks are used for hot milk, and temperatures of product including foam being held in the surge tank during processing, is not maintained at a minimum of 150 °F, then two or...

  14. Field assessment of surge and continuous furrow irrigation methods in relation to tillage systems

    Science.gov (United States)

    Mattar, Mohamed A.; El-Saadawy, Mohamed A.; Helmy, Mamdouh A.; Sorour, Hussien M.

    2017-04-01

    Surge flow irrigation is one of the irrigation techniques for controlling furrow irrigation. The aim of this study was to investigate the effect of surge furrow irrigation on water management compared with continuous irrigation for different tillage systems. An experimental field was treated with various tillage systems (mouldboard plough, chisel plough and rotary plough) and water irrigation application methods (continuous flow, control) in which irrigation water was applied continuously, and surge flow (3-surges, 4-surges and 5-surges) in which irrigation water was applied intermittently until it reached the tail end of the furrow. The results showed that water savings obtained using the surge technique were 18.58, 11.84 and 18.93% lower water use than with continuous flow, for the mouldboard, chisel and rotary ploughs, respectively. The 3-surges treatment with the rotary plough reduced the advance time by 25.36% from that for continuous irrigation. The 4-surges treatment with the mouldboard plough had the highest water application efficiency (88.13%). The 3-surges treatment with the rotary plough had the highest distribution uniformity (85.01%). The rotary plough did not cause as much soil aeration around the root system as the other tillage systems. The field research provided information about surge flow, aimed at reducing advance times and increasing irrigation efficiency.

  15. Storm surge model based on variational data assimilation method

    Directory of Open Access Journals (Sweden)

    Shi-li Huang

    2010-06-01

    Full Text Available By combining computation and observation information, the variational data assimilation method has the ability to eliminate errors caused by the uncertainty of parameters in practical forecasting. It was applied to a storm surge model based on unstructured grids with high spatial resolution meant for improving the forecasting accuracy of the storm surge. By controlling the wind stress drag coefficient, the variation-based model was developed and validated through data assimilation tests in an actual storm surge induced by a typhoon. In the data assimilation tests, the model accurately identified the wind stress drag coefficient and obtained results close to the true state. Then, the actual storm surge induced by Typhoon 0515 was forecast by the developed model, and the results demonstrate its efficiency in practical application.

  16. Dune erosion during storm surges

    NARCIS (Netherlands)

    Van Thiel de Vries, J.S.M.

    2009-01-01

    Large parts of The Netherlands are protected from flooding by a narrow strip of sandy beaches and dunes. The aim of this thesis is to extend the existing knowledge of dune erosion during storm surges as it occurs along the Dutch coast. The thesis discusses: • A large scale dune erosion experiment to

  17. Atlantic hurricane surge response to geoengineering

    Energy Technology Data Exchange (ETDEWEB)

    Moore, John C.; Grinsted, Aslak; Guo, Xiaoran; Yu, Xiaoyong; Jevrejeva, Svetlana; Rinke, Annette; Cui, Xuefeng; Kravitz, Ben; Lenton, Andrew; Watanabe, Shingo; Ji, Duoying

    2015-10-26

    Devastating Atlantic hurricanes are relatively rare events. However their intensity and frequency in a warming world may rapidly increase by a factor of 2-7 for each degree of increase in mean global temperature. Geoengineering by stratospheric sulphate aerosol injection cools the tropics relative to the polar regions, including the hurricane main development region in the Atlantic, suggesting that geoengineering may be an effective method of controlling hurricanes. We examine this hypothesis using 8 Earth System Model simulations of climate under the GeoMIP G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the RCP4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those in RCP4.5, but sulphate injection would have to double between 2020 and 2070 to balance RCP 4.5 to nearly 10 Tg SO2 yr-1, with consequent implications for damage to stratospheric ozone. We project changes in storm frequencies using a temperature-dependent Generalized Extreme Value statistical model calibrated by historical storm surges from 1923 and observed temperatures. The numbers of storm surge events as big as the one that caused the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this is only marginally statistically significant. However, when sea level rise differences at 2070 between RCP4.5 and geoengineering are factored in to coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5 year events and perhaps halved for 50 year surges.

  18. Surge-type and surge-modified glaciers in the Karakoram.

    Science.gov (United States)

    Bhambri, R; Hewitt, K; Kawishwar, P; Pratap, B

    2017-11-13

    Glaciers in the Karakoram exhibit irregular behavior. Terminus fluctuations of individual glaciers lack consistency and, unlike other parts of the Himalaya, total ice mass remained stable or slightly increased since the 1970s. These seeming anomalies are addressed through a comprehensive mapping of surge-type glaciers and surge-related impacts, based on satellite images (Landsat and ASTER), ground observations, and archival material since the 1840s. Some 221 surge-type and surge-like glaciers are identified in six main classes. Their basins cover 7,734 ± 271 km2 or ~43% of the total Karakoram glacierised area. Active phases range from some months to over 15 years. Surge intervals are identified for 27 glaciers with two or more surges, including 9 not previously reported. Mini-surges and kinematic waves are documented and surface diagnostic features indicative of surging. Surge cycle timing, intervals and mass transfers are unique to each glacier and largely out-of-phase with climate. A broad class of surge-modified ice introduces indirect and post-surge effects that further complicate tracking of climate responses. Mass balance in surge-type and surge-modified glaciers differs from conventional, climate-sensitive profiles. New approaches are required to account for such differing responses of individual glaciers, and effectively project the fate of Karakoram ice during a warming climate.

  19. Surge Tank Atlas for Hydropower Plants

    OpenAIRE

    Sandvåg, Simon Utseth

    2016-01-01

    The objective of this master's thesis is to describe the existing surge tank solutions and additional improvements, and to simulate the hydraulic behavior of the surge tanks and how it affects the hydropower plant. The high head hydropower plant Torpa and the low head hydropower plant Åna-Sira are used for the case study, thus the surge tanks can be simulated under different hydraulic conditions. Turbine pressures and mass oscillations after a complete turbine shutdown, and turbine regulation...

  20. Community health facility preparedness for a cholera surge in Haiti.

    Science.gov (United States)

    Mobula, Linda Meta; Jacquet, Gabrielle A; Weinhauer, Kristin; Alcidas, Gladys; Thomas, Hans-Muller; Burnham, Gilbert

    2013-01-01

    With increasing population displacement and worsening water insecurity after the 2010 earthquake, Haiti experienced a large cholera outbreak. Our goal was to evaluate the strengths and weaknesses of seven community health facilities' ability to respond to a surge in cholera cases. Since 2010, Catholic Relief Services (CRS) with a number of public and private donors has been working with seven health facilities in an effort to reduce morbidity and mortality from cholera infection. In November 2012, CRS through the Centers for Disease Control and Prevention (CDC)'s support, asked the Johns Hopkins Center for Refugee and Disaster Response to conduct a cholera surge simulation tabletop exercise at these health facilities to improve each facility's response in the event of a cholera surge. Using simulation development guidelines from the Pan American Health Organization and others, a simulation scenario script was produced that included situations of differing severity, supply chain, as well as a surge of patients. A total of 119 hospital staff from seven sites participated in the simulation exercise including community health workers, clinicians, managers, pharmacists, cleaners, and security guards. Clinics that had challenges during the simulated clinical care of patients were those that did not appropriately treat all cholera patients according to protocol, particularly those that were vulnerable, those that would need additional staff to properly treat patients during a surge of cholera, and those that required a better inventory of supplies. Simulation-based activities have the potential to identify healthcare delivery system vulnerabilities that are amenable to intervention prior to a cholera surge.

  1. [Morning surge and sleep surge in blood pressure--new clinical insights].

    Science.gov (United States)

    Kario, Kazuomi

    2011-11-01

    There are 2 new clinical insights of blood pressure (BP) surge. One is that the exaggerated BP surge is risk of target organ damage and future cardiovascular events, independently of the average of the 24-hr BP level (Kario K: Hypertension 56: 765-773, 2010). The cardiovascular risk is potentiated at the time period of the exaggerated BP surge. In hypertensive patiens who exhibit morning BP surge, cardiovascular events occur most frequently in the morning, while in the obstructive sleep apnea patients who exhibit sleep BP surge, cardiovascular events occur most frequently during sleep period. Another aspect is that the exaggerated BP surge is the "prehypertension" which precede hypertension (Kario K: J Hypertens 25: 1573-1575, 2007). The new BP monitoring device which detect BP surge reproducibly would clarify clinical implication of BP surge more extensively.

  2. Surge-type and surge-modified glaciers in the Karakoram

    OpenAIRE

    Bhambri, R.; Hewitt, K.; P. Kawishwar; Pratap, B

    2017-01-01

    Glaciers in the Karakoram exhibit irregular behavior. Terminus fluctuations of individual glaciers lack consistency and, unlike other parts of the Himalaya, total ice mass remained stable or slightly increased since the 1970s. These seeming anomalies are addressed through a comprehensive mapping of surge-type glaciers and surge-related impacts, based on satellite images (Landsat and ASTER), ground observations, and archival material since the 1840s. Some 221 surge-type and surge-like glaciers...

  3. Reconnaissance level study Mississippi storm surge barrier

    NARCIS (Netherlands)

    Van Ledden, M.; Lansen, A.J.; De Ridder, H.A.J.; Edge, B.

    2012-01-01

    This paper reports a reconnaissance level study of a storm surge barrier in the Mississippi River. Historical hurricanes have shown storm surge of several meters along the Mississippi River levees up to and upstream of New Orleans. Future changes due to sea level rise and subsidence will further

  4. Luminescence dating of storm-surge sediment

    NARCIS (Netherlands)

    Cunningham, A.C.

    2011-01-01

    Geological evidence of storm surges has the potential to provide vital information on storm-surge risk. Sediment from the coastal dunes of the Netherlands contains evidence of extreme floods that occurred before reliable measurements of water level began. For these sediments to be useful in

  5. Storm surge and tidal range energy

    Science.gov (United States)

    Lewis, Matthew; Angeloudis, Athanasios; Robins, Peter; Evans, Paul; Neill, Simon

    2017-04-01

    The need to reduce carbon-based energy sources whilst increasing renewable energy forms has led to concerns of intermittency within a national electricity supply strategy. The regular rise and fall of the tide makes prediction almost entirely deterministic compared to other stochastic renewable energy forms; therefore, tidal range energy is often stated as a predictable and firm renewable energy source. Storm surge is the term used for the non-astronomical forcing of tidal elevation, and is synonymous with coastal flooding because positive storm surges can elevate water-levels above the height of coastal flood defences. We hypothesis storm surges will affect the reliability of the tidal range energy resource; with negative surge events reducing the tidal range, and conversely, positive surge events increasing the available resource. Moreover, tide-surge interaction, which results in positive storm surges more likely to occur on a flooding tide, will reduce the annual tidal range energy resource estimate. Water-level data (2000-2012) at nine UK tide gauges, where the mean tidal amplitude is above 2.5m and thus suitable for tidal-range energy development (e.g. Bristol Channel), were used to predict tidal range power with a 0D modelling approach. Storm surge affected the annual resource estimate by between -5% to +3%, due to inter-annual variability. Instantaneous power output were significantly affected (Normalised Root Mean Squared Error: 3%-8%, Scatter Index: 15%-41%) with spatial variability and variability due to operational strategy. We therefore find a storm surge affects the theoretical reliability of tidal range power, such that a prediction system may be required for any future electricity generation scenario that includes large amounts of tidal-range energy; however, annual resource estimation from astronomical tides alone appears sufficient for resource estimation. Future work should investigate water-level uncertainties on the reliability and

  6. Influence of Surge on Extreme Roll Amplitudes

    DEFF Research Database (Denmark)

    Vidic-Perunovic, Jelena; Rognebakke, Olav; Pedersen, Preben Terndrup

    2008-01-01

    Interference of the wave-induced ship surge motion with roll dynamics has been studied. The surge motion has been included in a previously derived hydrodynamic roll prediction model in order to account for the ship speed variation due to the longitudinal incident wave pressure force. Depending...... on the position of the wave crest relatively to the ship, the ship will be slowed down when she meets the wave. In this paper attempts are made to accurately account for added resistance and additional thrust, applied in order to maintain the ship speed. The surge equilibrium equation has been longitudinally...

  7. The relationship between a blunted morning surge and a reversed nocturnal blood pressure dipping or "riser" pattern.

    Science.gov (United States)

    Fujiwara, Takeshi; Tomitani, Naoko; Sato, Keiko; Okura, Ayako; Suzuki, Noriyuki; Kario, Kazuomi

    2017-11-01

    The authors sought to determine the association between the blunted morning blood pressure (BP) surge and nocturnal BP dipping of the "riser" pattern in 501 patients with hypertension enrolled in the ACHIEVE-ONE (Ambulatory Blood Pressure Control and Home Blood Pressure [Morning and Evening] Lowering by the N-Channel Blocker Cilnidipine) trial. The patients' sleep-trough morning BP surge and prewaking surge were calculated and then classified according to their nocturnal systolic BP reduction pattern as extreme dippers, dippers, nondippers, and risers. The prevalence of the riser pattern was significantly higher in both the lowest sleep-trough morning BP surge decile and the prewaking surge decile (blunted surge group) compared with the remaining deciles (56.0% vs 10.4% [Psurge (odds ratio, 73.3; Psurge (odds ratio, 14.8; Psurges may account for the cardiovascular risk previously reported in such patients. ©2017 Wiley Periodicals, Inc.

  8. Physical attributes of hurricane surges and their role in surge warning

    Science.gov (United States)

    Irish, J. L.

    2012-12-01

    In the last decade, the US has experienced some of its largest surges and hurricane-related damages on record. Effective evacuation in advance of a hurricane strike requires accurate estimation of the hurricane surge hazard that effectively conveys risk not only to government decision makers but also to the general public. Two primary challenges exist with the current structure for surge warning. First, existing computational methods for developing accurate, quantitative surge forecasts, namely surge height and inundation estimation, are limited by time and computational resources. Second, due primarily to the popularity and wide use of the Saffir-Simpson wind scale to convey the complete hurricane hazard, the public's perception of surge hazard is inaccurate. Here, we use dimensionless scaling and hydrodynamics arguments to quantify the influence of hurricane variables and regional geographic characteristics on the surge response. It will be shown that hurricane surge primarily scales with the hurricane's central pressure, and size and with continental shelf width at the landfall location (Irish et al. 2009, Nat. Haz.; Song et al. in press, Nat. Haz.). Secondary influences include the hurricane's forward speed and path. The developed physical scaling is applied in two ways: (1) as a means for expanding the utility of computational simulations for real-time surge height forecasting and (2) as a means to convey relative surge hazard via a readily evaluated algebraic surge scale. In the first application, the use of this physical scaling to develop surge response functions (SRF) enables instantaneous algebraic calculation of maximum surge height at any location of interest for any hurricane meteorological condition, without loss of accuracy gained via high-resolution computational simulation. When coupled with joint probability statistics, the use of SRFs enables rapid development of continuous probability density functions for probabilistic surge forecasting (Irish

  9. Cold Surge Activity Over the Gulf of Mexico in a Warmer Climate

    Directory of Open Access Journals (Sweden)

    Edgar Perez Perez

    2014-08-01

    Full Text Available Cold surges are a dominant feature of midlatitude tropical interaction. During the North Hemisphere (NH winter, midlatitude waves propagating from the Rocky Mountains into the Gulf of Mexico result in cold surges, also known as Nortes or Tehuantepecers, associated with severe weather over the southern part of Mexico. The magnitude of their intense surface winds, precipitation and drops in surface temperature depends on the characteristics of the midlatitude wave propagating into the tropics. The high spatial resolution (20km X 20km version of the TL959L60-AGC Model of the Meteorological Research Institute of Japan is used to examine changes in cold surge activity under the A1B greenhouse gas emission scenario for the 2080 - 2099 period. The model realistically reproduces the spatial and temporal characteristics of cold surges for the 1980 - 1989 control period. The effect of changes in baroclinicity, static stability and mean flow over North America suggest that in a warmer climate, increased cold surge activity over the Gulf of Mexico would occur. However, these systems would have shorter wavelength (higher phase speeds and shorter lifespans that could reduce the total amount of winter precipitation. The increased frequency of cold surges over the Gulf of Mexico would be a consequence of weaker baroclinicity and static stability in the lower troposphere over the cold surge genesis region, along with more dominant westerly winds, resulting from ENSO-like conditions in the atmospheric circulations over North America.

  10. 48 CFR 252.217-7001 - Surge option.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Surge option. 252.217-7001... Clauses 252.217-7001 Surge option. As prescribed in 217.208-70(b), use the following clause: Surge Option... established by negotiation as provided in this clause. (b) Schedule. (1) When the Production Surge Plan (DI...

  11. Surge Capacity of Hospitals in Emergencies and Disasters With a Preparedness Approach: A Systematic Review.

    Science.gov (United States)

    Sheikhbardsiri, Hojjat; Raeisi, Ahmad Reza; Nekoei-Moghadam, Mahmood; Rezaei, Fatemeh

    2017-10-01

    Surge capacity is one of the most important components of hospital preparedness for responding to emergencies and disasters. The ability to provide health and medical care during a sudden increase in the number of patients or victims of disasters is a main concern of hospitals. We aimed to perform a systematic review of hospital surge capacity in emergencies and disasters with a preparedness approach. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The key words "surge," "surge capacity," "preparedness," "hospital emergency department," "hospital," "surge capability," "emergency," "hazard," "disaster," "catastrophe," "crisis," and "tragedy" were used in combination with the Boolean operators OR and AND. The Google Scholar, ISI Web of Science, Science Direct, PubMed, Scopus, Ovid, Pro Quest, and Wiley databases were searched. A total of 1008 articles were extracted and 17 articles were selected for final review of surge capacity based on the objective of the study. Seventeen studies (1 randomized controlled trial, 2 qualitative studies, and 14 cross-sectional studies) investigated the surge capacity of hospitals in emergencies and disasters to evaluate the best evidence to date. The results of selected articles indicated that there are various ways to increase the capacity of hospitals in 4 domains: staff, stuff, structure, and system. Surge capacity is a basic element of disaster preparedness programs. Results of the current study could help health field managers in hospitals to prepare for capacity-building based on surge capacity components to improve and promote hospital preparedness programs. (Disaster Med Public Health Preparedness. 2017;11:612-620).

  12. Race, plasma renin activity, and morning blood pressure surge--results from the Dietary Approaches to Stop Hypertension trial.

    Science.gov (United States)

    Mc Causland, Finnian R; McMullan, Ciaran J; Sacks, Frank M; Forman, John P

    2014-04-01

    The association of preawake (difference between pre- and postwaking blood pressure (BP)) and sleep-through surge (difference between sleeping nadir and postwaking BP) with cardiovascular events is unclear. Examination of factors associated with surge may provide novel insights. We examined the association of race, which associates with nocturnal dipping, and plasma renin activity (PRA) with preawake and sleep-through surge among individuals on a controlled diet. We performed a post hoc analysis of 323 subjects from the Dietary Approaches to Stop Hypertension trial who had available 24-hour BP data and who ingested a control diet during a 3-week run-in period. Linear regression models were fit to estimate the association of race and PRA with preawake and sleep-through surge. Of the 323 individuals, 55% were black, 53% were men, and the average age was 45 years. After controlling for other factors, black race was associated with a 3.2mm Hg lower preawake and a 3.7mm Hg lower sleep-through surge compared with nonblacks. In nonblacks, higher PRA was associated with greater preawake surge only. There was no association of PRA with either preawake or sleep-through surge in blacks. Additional adjustment for dipping status resulted in attenuation of the race-surge associations. Black race is associated with lower preawake and sleep-through surge compared with nonblacks, but the effect is partially attenuated by dipping status. Higher PRA appears to be associated with a higher preawake surge in nonblacks only. Further research should address if morning surge is definitively associated with clinical outcomes in racial subgroups, independent of dipping.

  13. A surge in anti-dsDNA titer predicts a severe lupus flare within six months.

    Science.gov (United States)

    Pan, N; Amigues, I; Lyman, S; Duculan, R; Aziz, F; Crow, M K; Kirou, K A

    2014-03-01

    Rising anti-double-stranded (ds) DNA titers have been shown by some, but not all, studies to be predictive of disease flares in systemic lupus erythematosus (SLE). We hypothesized that a rapid and substantial rise in anti-dsDNA titer (anti-dsDNA surge) would be a good predictor of a clinically important SLE flare. A matched case-control study was conducted in an academic rheumatology practice setting. Our primary endpoint was the occurrence of a severe SELENA-SLEDAI (SS) flare within six months of an anti-dsDNA surge, and secondary endpoints were mild/moderate SS flares, as well as BILAG A and B renal flares. Cases were identified as those patients whose disease course included a surge of anti-dsDNA, defined as an increase of anti-dsDNA titer by the Crithidia luciliae immunofluorescence (CLIF) assay from 0 to 3+/4+, or from 1+ to 4+, within a period of less than 12 months. The date of the anti-dsDNA surge was defined as Day 0. Two control SLE patients were identified for each case and were matched for age, sex, race, and visit date closest to case Day 0, but without an anti-dsDNA surge. Logistic regression models were used to detect associations between anti-dsDNA surges and severe SS flares. A higher proportion of cases, compared to controls, experienced a severe SS flare within six months of Day 0 (OR 6.3 (95% confidence intervals 2.0-19.9), p = 0.02). Associations with all flares and hospitalizations for flares were also observed. However, an anti-dsDNA surge was not predictive of a renal flare. An anti-dsDNA surge predicts the subsequent development of a severe SS flare within six months. Physicians should closely monitor such patients and treat promptly at the first sign of clinical activity.

  14. Evaluation of surge protection in underground distribution systems using zinc oxide (metal oxide) surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Banda, J.

    1985-01-01

    Application of zinc oxide arresters represents a significant development in surge protection. One area of distribution system protection where the new arrester technology can be immediately valuable is underground distribution system protection. Increasing system voltage levels and the economic advantages of lower basic insulation level have led to increased interest in improving protection of underground distribution system equipment. Because conventional silicon-carbide surge arresters have not met the challenges imposed by system requirements, costly alternatives such as paralleling arresters have been used in an attempt to limit surges imposed on systems. In this thesis differences between the two types of arresters are reviewed, and an evaluation of surge protection employing zinc oxide arresters in underground distribution systems is carried out. In order to evaluate zinc oxide surge arrester's performance under various conditions, transient phenomena of single- and multi-line underground distribution systems, with and without surge arresters, are studied. The conditions considered include; (i) low and high surge impedance systems, (ii) slow and fast front surges and (iii) different line terminations. Actual data obtained from a typical and operative underground distribution system is used in the study.

  15. Global mortality from storm surges is decreasing

    Science.gov (United States)

    Bouwer, Laurens M.; Jonkman, Sebastiaan N.

    2018-01-01

    Changes in society’s vulnerability to natural hazards are important to understand, as they determine current and future risks, and the need to improve protection. Very large impacts including high numbers of fatalities occur due to single storm surge flood events. Here, we report on impacts of global coastal storm surge events since the year 1900, based on a compilation of events and data on loss of life. We find that over the past, more than eight thousand people are killed and 1.5 million people are affected annually by storm surges. The occurrence of very substantial loss of life (>10 000 persons) from single events has however decreased over time. Moreover, there is a consistent decrease in event mortality, measured by the fraction of exposed people that are killed, for all global regions, except South East Asia. Average mortality for storm surges is slightly higher than for river floods, but lower than for flash floods. We also find that for the same coastal surge water level, mortality has decreased over time. This indicates that risk reduction efforts have been successful, but need to be continued with projected climate change, increased rates of sea-level rise and urbanisation in coastal zones.

  16. Traumatic asphyxia following stadium crowd surge: stadium factors affecting outcome.

    Science.gov (United States)

    DeAngeles, D; Schurr, M; Birnbaum, M; Harms, B

    1998-10-01

    Stadium crowd surges frequently occur following major athletic events. A recent crowd surge injured more than 80 persons by trampling and/or crushing. This incident was reviewed to identify injury patterns consistent with crush-related injury. In addition, the incident was reviewed to determine which stadium policy and design factors may have potentiated this event. A recent crowd surge occurred following a college football game. This resulted in 86 people being transported to the University of Wisconsin and other area hospitals. All charts were reviewed to evaluate patient outcomes. The stadium was examined as were security system video tapes to evaluate stadium factors that contributed to this event. Current policies were obtained through the university sports administration. Of 86 patients transported for evaluation of stadium-related injuries, 10 were treated for traumatic asphyxia. Other injuries requiring hospital admission included musculo-skeletal trauma in two patients and one grade II liver injury. Six others were admitted overnight for observation. Several stadium factors were identified that contributed to the event, and appropriate changes in crowd control policies and stadium design were instated to prevent recurrence. This report details the largest single report of traumatic asphyxia second to the England Hillsborough disaster. Several stadium factors were identified that resulted in crush-related injury. Cooperative review and modification of stadium policies and design may prevent such events in the future.

  17. Positive Surge Propagation in Sloping Channels

    Directory of Open Access Journals (Sweden)

    Daniele Pietro Viero

    2017-07-01

    Full Text Available A simplified model for the upstream propagation of a positive surge in a sloping, rectangular channel is presented. The model is based on the assumptions of a flat water surface and negligible energy dissipation downstream of the surge, which is generated by the instantaneous closure of a downstream gate. Under these hypotheses, a set of equations that depends only on time accurately describes the surge wave propagation. When the Froude number of the incoming flow is relatively small, an approximate analytical solution is also proposed. The predictive ability of the model is validated by comparing the model results with the results of an experimental investigation and with the results of a numerical model that solves the full shallow water equations.

  18. Adaptive mesh refinement for storm surge

    KAUST Repository

    Mandli, Kyle T.

    2014-03-01

    An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the GeoClaw framework and compared to ADCIRC for Hurricane Ike along with observed tide gauge data and the computational cost of each model run. © 2014 Elsevier Ltd.

  19. Effect of Hydraulic Accumulator on Pressure Surge of a Hydrostatic Transmission System

    Science.gov (United States)

    Kumar, Ajit; Das, Jayanta; Dasgupta, Kabir; Barnwal, Manish Kumar

    2017-05-01

    Hydraulic power system is generally used in off-road vehicles for power transmission such as Heavy Earth Moving Machineries (HEMM). Their energy efficiency and unsubstantial failure becomes an extensive subject of analysis. Various arrangements in the system are compassed along with the utilization of some appropriate components. Application of a hydraulic accumulator is one among them. Benefits of accumulator is its multi-purpose usages like energy saving and pressure surge damping. This paper deals with the control of pressure surges in the hydraulic system and energy saving from the surges by using accumulator. For this purpose, the simulation of the hydraulic system is done in MATLAB/SimulinkR environment and an external disturbance is introduced to generate the pressure surge. The surge absorptivity of the accumulator is studied for different sizes at different pre-charged conditions of the accumulator. The discharge characteristics of different sized accumulators are also analyzed in this paper. It is observed that the ability to absorb the surge and stabilize the system is high in the smaller capacity accumulator. However the energy delivery time of larger sized accumulator is high.

  20. Modeling and simulation of storm surge on Staten Island to understand inundation mitigation strategies

    Science.gov (United States)

    Kress, Michael E.; Benimoff, Alan I.; Fritz, William J.; Thatcher, Cindy A.; Blanton, Brian O.; Dzedzits, Eugene

    2016-01-01

    Hurricane Sandy made landfall on October 29, 2012, near Brigantine, New Jersey, and had a transformative impact on Staten Island and the New York Metropolitan area. Of the 43 New York City fatalities, 23 occurred on Staten Island. The borough, with a population of approximately 500,000, experienced some of the most devastating impacts of the storm. Since Hurricane Sandy, protective dunes have been constructed on the southeast shore of Staten Island. ADCIRC+SWAN model simulations run on The City University of New York's Cray XE6M, housed at the College of Staten Island, using updated topographic data show that the coast of Staten Island is still susceptible to tidal surge similar to those generated by Hurricane Sandy. Sandy hindcast simulations of storm surges focusing on Staten Island are in good agreement with observed storm tide measurements. Model results calculated from fine-scaled and coarse-scaled computational grids demonstrate that finer grids better resolve small differences in the topography of critical hydraulic control structures, which affect storm surge inundation levels. The storm surge simulations, based on post-storm topography obtained from high-resolution lidar, provide much-needed information to understand Staten Island's changing vulnerability to storm surge inundation. The results of fine-scale storm surge simulations can be used to inform efforts to improve resiliency to future storms. For example, protective barriers contain planned gaps in the dunes to provide for beach access that may inadvertently increase the vulnerability of the area.

  1. The dynamics of surge in compression systems

    Indian Academy of Sciences (India)

    In air-compression systems, instabilities occur during operation close to their peak pressure-rise capability. However, the peak efficiency of a compression system lies close to this region of instability. A surge is a violent mode of instability where there is total breakdown of flow in the system and pressure-rise capability is lost ...

  2. The dynamics of surge in compression systems

    Indian Academy of Sciences (India)

    compression systems, instabilities occur during operation close to their peak pressure-rise capability. However, the peak efficiency of a compression system lies close to this region of instability. A surge is a violent mode of instability where there is total ...

  3. Effect of piping systems on surge in centrifugal compressors

    Energy Technology Data Exchange (ETDEWEB)

    Tamaki, Hideaki [Products Development Center, Yokohama (Japan)

    2008-10-15

    There is a possibility that the exchange of the piping system may change the surge characteristic of a compressor. The piping system of a plant is not always the same as that of a test site. Then it is important to evaluate the effect of piping systems on surge characteristics in centrifugal compressors. Several turbochargers combined with different piping systems were tested. The lumped parameter model which was simplified to be solved easily was applied for the prediction of surge point. Surge lines were calculated with the linearlized lumped parameter model. The difference between the test and calculated results was within 10 %. Trajectory of surge cycle was also examined by solving the lumped parameter model. Mild surge and deep surge were successfully predicted. This study confirmed that the lumped parameter model was a very useful tool to predict the effect of piping systems on surge characteristics in centrifugal compressors, even though that was a simple model

  4. Evidence for a luteinizing hormone surge center in the hypothalamus of the pig.

    Science.gov (United States)

    Kraeling, R R; Johnson, B; Barb, C R; Rampacek, G B

    1998-05-01

    Studies were conducted to determine whether there is an LH surge generator in the hypothalamus of the pig. In experiment 1, 157-day-old ovariectomized (OVX) gilts received 1.5 microg estradiol benzoate (EB)/kg BW i.m. every 12 h from 0 through 24, 48, 72, or 96 h. Blood was sampled every 6 h from 3 to 36 h and every 3 h from 36 through 144 h. One of 3, 4 of 4, 4 of 4, and 2 of 3 gilts displayed an LH surge after treatment for 24, 48, 72, and 96 h, respectively. With the exception that time to maximum LH concentration was greater in gilts treated for 96 h than in those treated for 72 h (p gilts. In experiment 2a, an Alzet osmotic pump containing EB or vehicle was inserted s.c. behind an ear of 124-day-old OVX gilts, resulting in the following daily doses of EB: 0, 0.75, 1.50, or 3.00 microg/kg BW. Blood was sampled at 0, 2, 4, 6, and 8 h and every 8 h thereafter through 168 h to evaluate surge secretion of LH, and every 15 min for 8 h starting at 168 h to evaluate pulsatile LH secretion. Zero of 3, 0 of 2, 3 of 3, and 3 of 3 gilts displayed an LH surge after 0, 0.75, 1.50, and 3.00 microg EB/kg BW, respectively. Parameters of the surge were similar among gilts. Pulsatile LH secretion, evaluated 7 days after pump insertion, was significantly suppressed for estradiol-treated gilts compared to controls. In experiment 2b, at 182 days of age, 10 gilts used in experiment 2a plus 2 additional gilts in the original group prepared but not used for experiment 2a, were randomly assigned in groups (n=3) to the following daily doses of EB: 0, 0.19, 0.38, or 0.75 microg/kg BW, administered again by osmotic pump. Treatment and blood-sampling schedules were the same as in experiment 2a. Zero, 0, 1, and 2 gilts displayed an LH surge after treatment with 0, 0.19, 0.38, and 0.75 microg EB/kg BW, respectively. Parameters of the surge were similar among gilts that displayed an LH surge. Pulsatile LH secretion was significantly suppressed for estradiol-treated gilts compared to controls

  5. Surge arresters - Part 5: Selection and application recommendations

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2000-01-01

    Provides recommendations for the selection and application of surge arresters to be used in three-phase systems with nominal voltages above 1kV. It applies to non-linear resistor type gapped surge arresters as defined in IEC 60099-1 and to gapless metal-oxide surge arresters as defined in IEC 60099-4.

  6. 30 CFR 77.209 - Surge and storage piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Surge and storage piles. 77.209 Section 77.209... Installations § 77.209 Surge and storage piles. No person shall be permitted to walk or stand immediately above a reclaiming area or in any other area at or near a surge or storage pile where the reclaiming...

  7. Aspects of gulf surges and tropical upper tropospheric troughs in the North American monsoon

    Science.gov (United States)

    Newman, Andrew James

    2011-12-01

    Gulf surges are transient events that propagate along the Gulf of California (GoC) from south to north, transporting cool moist air toward the deserts of northwest Mexico and the southwest United States during the North American monsoon (NAM). The general features and progression of surge events are well studied but the dynamical characteristics and evolution are still unclear. Tropical upper-tropospheric troughs (TUTTs) are another critical transient event occurring during the NAM that enhance precipitation on their western flank. The mechanism of precipitation enhancement associated with TUTT passage needs further refinement as well. To address these unknowns, a number of convection-permitting simulations are performed over the entire core monsoon region for the 12--14 July 2004 gulf surge and TUTT event that occurred during the North American Monsoon Experiment. This allows for extensive comparison with many observational platforms. A control simulation is able to reproduce the surge event reasonably well, capturing all the important observed features on 12 and 13 July. The dynamical evolution of the surge event notes two distinct features, a precursor event on 12 July and the actual surge on 13 July. Using shallow water theory, the feature on 12 July is likely a coastally trapped, slightly non-linear Kelvin wave. This feature is important because it introduces cooler, moister air into the southern and central GoC. The surge signature develops early on 13 July in the southern GoC and is likely a coastally trapped non-linear Kelvin wave throughout its lifetime. Sensitivity simulations show that the convective outflow is critical to the intensity of the simulated surge, in agreement with past studies. The removal of mountain gap flows into the GoC from the Pacific Ocean along the Baja Peninsula shows they are not critical in surge initiation and evolution; the surge and its general character remain. A unique approach to examine the TUTT precipitation enhancement

  8. Nonlinear chaotic model for predicting storm surges

    Directory of Open Access Journals (Sweden)

    M. Siek

    2010-09-01

    Full Text Available This paper addresses the use of the methods of nonlinear dynamics and chaos theory for building a predictive chaotic model from time series. The chaotic model predictions are made by the adaptive local models based on the dynamical neighbors found in the reconstructed phase space of the observables. We implemented the univariate and multivariate chaotic models with direct and multi-steps prediction techniques and optimized these models using an exhaustive search method. The built models were tested for predicting storm surge dynamics for different stormy conditions in the North Sea, and are compared to neural network models. The results show that the chaotic models can generally provide reliable and accurate short-term storm surge predictions.

  9. Runoff-generated debris flows: observations and modeling of surge initiation, magnitude, and frequency

    Science.gov (United States)

    Kean, Jason W.; McCoy, Scott W.; Tucker, Gregory E.; Staley, Dennis M.; Coe, Jeffrey A.

    2013-01-01

    Runoff during intense rainstorms plays a major role in generating debris flows in many alpine areas and burned steeplands. Yet compared to debris flow initiation from shallow landslides, the mechanics by which runoff generates a debris flow are less understood. To better understand debris flow initiation by surface water runoff, we monitored flow stage and rainfall associated with debris flows in the headwaters of two small catchments: a bedrock-dominated alpine basin in central Colorado (0.06 km2) and a recently burned area in southern California (0.01 km2). We also obtained video footage of debris flow initiation and flow dynamics from three cameras at the Colorado site. Stage observations at both sites display distinct patterns in debris flow surge characteristics relative to rainfall intensity (I). We observe small, quasiperiodic surges at low I; large, quasiperiodic surges at intermediate I; and a single large surge followed by small-amplitude fluctuations about a more steady high flow at high I. Video observations of surge formation lead us to the hypothesis that these flow patterns are controlled by upstream variations in channel slope, in which low-gradient sections act as “sediment capacitors,” temporarily storing incoming bed load transported by water flow and periodically releasing the accumulated sediment as a debris flow surge. To explore this hypothesis, we develop a simple one-dimensional morphodynamic model of a sediment capacitor that consists of a system of coupled equations for water flow, bed load transport, slope stability, and mass flow. This model reproduces the essential patterns in surge magnitude and frequency with rainfall intensity observed at the two field sites and provides a new framework for predicting the runoff threshold for debris flow initiation in a burned or alpine setting.

  10. Dynamic Model of Centrifugal Compressor for Prediction of Surge Evolution and Performance Variations

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Mooncheong; Han, Jaeyoung; Yu, Sangseok [Chungnam National Univ., Daejeon (Korea, Republic of)

    2016-05-15

    When a control algorithm is developed to protect automotive compressor surges, the simulation model typically selects an empirically determined look-up table. However, it is difficult for a control oriented empirical model to show surge characteristics of the super charger. In this study, a dynamic supercharger model is developed to predict the performance of a centrifugal compressor under dynamic load follow-up. The model is developed using Simulink® environment, and is composed of a compressor, throttle body, valves, and chamber. Greitzer’s compressor model is used, and the geometric parameters are achieved by the actual supercharger. The simulation model is validated with experimental data. It is shown that compressor surge is effectively predicted by this dynamic compressor model under various operating conditions.

  11. Modeling Storm Surges Using Discontinuous Galerkin Methods

    Science.gov (United States)

    2016-06-01

    analytical way to solve the non-linear SWE and therefore numerical methods are required. To solve this system of partial differential equations (PDE), dis...where λ , λ(q). To simplify the exposition let us describe how to solve Equation (2.20) explicitly using the Forward Euler (FE) method. FE is written as... Text , we used the shallow water wavelength equation, which is appropriate for storm surges since they typically have long wavelengths. The shallow

  12. Surge detection on an automotive turbocharger during transient phases

    Science.gov (United States)

    Deligant, M.; Danlos, A.; Podevin, P.; Clenci, A.; Guilain, S.

    2017-10-01

    The surge limit on automotive turbocharger needs to be avoided to prevent operations with pressure and mass flow oscillations. Mild surge is accompanied by noise which is disturbing. Deep surge can cause significant loss of engine power and severe drivability issues. It is necessary to know the stationary limit in order to match a turbocharger with an engine, ensuring enough surge margin. However, this choice does not guarantee surge free operation during transient functioning. In this paper, the surge onset of a compressor while closing a downstream valve is studied. Various tests have been carried out varying the closing time, the position of the initial operating point and the volume of the circuit. The inlet and outlet signals of physical parameters are analyzed with spectral and temporal methods in order to define the instant of the surge occurrence.

  13. Advances in using satellite altimetry to observe storm surge

    Science.gov (United States)

    Han, Guoqi

    2017-04-01

    Storm surges are the major cause for coastal flooding, resulting in catastrophic damage to properties and loss of life in coastal communities. Thus it is important to utilize new technology to enhance our capabilities of observing storm surges and ultimately to improve our capacity for forecasting storm surges and mitigating damage and loss. In this talk we first review traditional methods of monitoring storm surges. We then provide examples of storm surges observed by nadir satellite altimetry, during Hurricane Sandy and Igor, as well as typhoon and cyclone events. We further evaluate satellite results against tide-gauge data and explain storm surge features. Finally, we discuss the potential of a wide-swath altimetry mission, the Surface Water and Ocean Topography (SWOT), for observing storm surges.

  14. Spatio-temporal variations in storm surges along the North Atlantic coasts

    Science.gov (United States)

    Marcos, Marta; Woodworth, Philip

    2017-04-01

    Extreme sea levels along the coasts of the North Atlantic Ocean and the Gulf of Mexico have been investigated using hourly tide gauge records compiled in the recently released GESLA-2 data set (www.gesla.org). These regions are among the most densely monitored coasts worldwide, with more than 300 high frequency quality-controlled tide gauge time series available. Here we estimate the storm surge component of extreme sea levels using both tidal residuals and skew surges, for which we explore the spatial and temporal coherency of their intensities, duration and frequency. We quantify the relationship of extremes with dominant large scale climate patterns and discuss the impact of mean sea level changes. Finally, we test the assumption of stationarity of the probability of extreme occurrence and to which extent it holds when mean sea level changes are considered in combination with storm surges.

  15. Influence of Closing Storm Surge Barrier on Extreme Water Levels and Water Exchange; The Limfjord, Denmark

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck; Bentzen, Thomas Ruby; Larsen, Torben

    2014-01-01

    The Limfjord is the largest Danish estuary and is connected to both the North Sea in the west and the Kattegat in the east. The connection to the North Sea was formed in 1825 by a storm surge, and has since been kept open partly artificially. The debate about the climate changes and thereby...... the increased risk of flooding in the estuary has revitalized the discussion whether this connection should be closed. In this paper, it is shown by numerical simulation that the establishment of a storm surge barrier across Thyborøn Channel can significantly reduce the peak water levels in the central...... of the fjord. The reduction is obtained by blocking the ingoing flow with a sluice in due time before the storm surge peaks in the North Sea. In order to avoid problems with reduced water quality and salinity, the water exchange should be controlled by only keeping the sluice open for ingoing currents...

  16. Coastal emergency managers' preferences for storm surge forecast communication.

    Science.gov (United States)

    Morrow, Betty Hearn; Lazo, Jeffrey K

    2014-01-01

    Storm surge, the most deadly hazard associated with tropical and extratropical cyclones, is the basis for most evacuation decisions by authorities. One factor believed to be associated with evacuation noncompliance is a lack of understanding of storm surge. To address this problem, federal agencies responsible for cyclone forecasts are seeking more effective ways of communicating storm surge threat. To inform this process, they are engaging various partners in the forecast and warning process.This project focuses on emergency managers. Fifty-three emergency managers (EMs) from the Gulf and lower Atlantic coasts were surveyed to elicit their experience with, sources of, and preferences for storm surge information. The emergency managers-who are well seasoned in hurricane response and generally rate the surge risk in their coastal areas above average or extremely high-listed storm surge as their major concern with respect to hurricanes. They reported a general lack of public awareness about surge. Overall they support new ways to convey the potential danger to the public, including the issuance of separate storm surge watches and warnings, and the expression of surge heights using feet above ground level. These EMs would like more maps, graphics, and visual materials for use in communicating with the public. An important concern is the timing of surge forecasts-whether they receive them early enough to be useful in their evacuation decisions.

  17. AN EXTREME-ULTRAVIOLET WAVE ASSOCIATED WITH A SURGE

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Ruisheng; Jiang, Yunchun; Yang, Jiayan; Bi, Yi; Hong, Junchao; Yang, Bo; Yang, Dan, E-mail: zhrsh@ynao.ac.cn [National Astronomical Observatories/Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming 650011 (China)

    2013-02-10

    Taking advantage of the high temporal and spatial resolution observations from the Solar Dynamics Observatory, we present an extreme-ultraviolet (EUV) wave associated with a surge on 2010 November 13. Due to the magnetic flux cancelation, some surges formed in the source active region (AR). The strongest surge produced our studied event. The surge was deflected by the nearby loops that connected to another AR, and disrupted the overlying loops that slowly expanded and eventually evolved into a weak coronal mass ejection (CME). The surge was likely associated with the core of the CME. The EUV wave happened after the surge deflected. The wave departed far from the flare center and showed a close location relative to the deflected surge. The wave propagated in a narrow angular extent, mainly in the ejection direction of the surge. The close timing and location relations between the EUV wave and the surge indicate that the wave was closely associated with the CME. The wave had a velocity of 310-350 km s{sup -1}, while the speeds of the surge and the expanding loops were about 130 and 150 km s{sup -1}, respectively. All of the results suggest that the EUV wave was a fast-mode wave and was most likely triggered by the weak CME.

  18. Possible management of near shore nonlinear surging waves through bottom boundary conditions

    Science.gov (United States)

    Mukherjee, Abhik; Janaki, M. S.; Kundu, Anjan

    2017-03-01

    We propose an alternative way for managing near shore surging waves, including extreme waves like tsunamis, going beyond the conventional passive measures like the warning system. We study theoretically the possibility of influencing the nonlinear surface waves through a leakage boundary effect at the bottom. It has been found through analytic result, that the controlled leakage at the bottom might regulate the amplitude of the surface solitary waves. This could lead to a possible decay of the surging waves to reduce its hazardous effects near the shore. Our theoretical results are estimated by applying it to a real coastal bathymetry of the Bay of Bengal in India.

  19. Avoiding compressor surge during emergency shutdown hybridturbine systems

    Energy Technology Data Exchange (ETDEWEB)

    Pezzini, Paolo [University of Genova, Italy; Tucker, David [U.S. DOE; Traverso, Alberto [University of Genova, Italy

    2013-01-01

    A new emergency shutdown procedure for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle (IGFC), implemented through the Hybrid Performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test, and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide a means of quantifying risk mitigation strategies. An open-loop system analysis regarding the dynamic effect of bleed air, cold air bypass, and load bank is presented in order to evaluate the combination of these three main actuators during emergency shutdown. In the previous Hybrid control system architecture, catastrophic compressor failures were observed when the fuel and load bank were cut off during emergency shutdown strategy. Improvements were achieved using a nonlinear fuel valve ramp down when the load bank was not operating. Experiments in load bank operation show compressor surge and stall after emergency shutdown activation. The difficulties in finding an optimal compressor and cathode mass flow for mitigation of surge and stall using these actuators are illustrated.

  20. Simulated storm surge effects on freshwater coastal wetland soil porewater salinity and extractable ammonium levels: Implications for marsh recovery after storm surge

    Science.gov (United States)

    McKee, M.; White, J. R.; Putnam-Duhon, L. A.

    2016-11-01

    Coastal wetland systems experience both short-term changes in salinity, such as those caused by wind-driven tides and storm surge, and long-term shifts caused by sea level rise. Salinity increases associated with storm surge are known to have significant effects on soil porewater chemistry, but there is little research on the effect of flooding length on salt penetration depth into coastal marsh soils. A simulated storm surge was imposed on intact soil columns collected from a non-vegetated mudflat and a vegetated marsh site in the Wax Lake Delta, LA. Triplicate intact cores were continuously exposed to a 35 salinity water column (practical salinity scale) for 1, 2, and 4 weeks and destructively sampled in order to measure porewater salinity and extractable NH4sbnd N at two cm depth intervals. Salinity was significantly higher in the top 8 cm for both the marsh and mudflat cores after one week of flooding. After four weeks of flooding, salinity was significantly higher in marsh and mudflat cores compared to the control (no salinity) cores throughout the profile for both sites. Extractable ammonium levels increased significantly in the marsh cores throughout the experiment, but there was only a marginally (p < 0.1) significant increase seen in the mudflat cores. Results indicate that porewater salinity levels can become significantly elevated within a coastal marsh soil in just one week. This vertical intrusion of salt can potentially negatively impact macrophytes and associated microbial communities for significantly longer term post-storm surge.

  1. Surge hindcast in the East China sea

    Science.gov (United States)

    Choi, B. H.

    Two typhoon surges generated during July-August 1978 are investigated numerically with the use of a vertically-integrated finite-difference model of the Yellow Sea and the East China Sea. The hindcast scheme involves processing pressure data from weather charts to provide the necessary meteorological forcing to a sea model that computes the response in terms of water levels and currents. Computed residuals are compared with hourly records from selected tide gauges (Inchon, Kunsan, Mokpo, Jeju and Yeosu) along the coast of Korea. Some of the preliminary results are presented and discussed.

  2. Using Wind Setdown and Storm Surge on Lake Erie to Calibrate the Air-Sea Drag Coefficient

    Science.gov (United States)

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

  3. Using wind setdown and storm surge on Lake Erie to calibrate the air-sea drag coefficient.

    Directory of Open Access Journals (Sweden)

    Carl Drews

    Full Text Available The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST modeling system and the the Regional Ocean Modeling System (ROMS. Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN. Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1.

  4. Fall-experiments to better constrain cliff-triggered surges in pyroclastic flows

    Science.gov (United States)

    Schwarzkopf, L. M.; Spieler, O.; Dingwell, D. B.

    2003-04-01

    Recent eruptions of Unzen, Soufriere Hills and Merapi have demonstrated the hazard potential of dome forming stratovolcanoes. The dominant process during these events was a type of low volume pyroclastic flow, termed block-and-ash flow (BAF). BAFs consist of basal avalanches and overriding ash clouds, many being accompanied or preceded by surges, hot and gas-rich high-speed particle flows. The dense basal avalanches are gravity-driven and follow valleys, but surges commonly sweep over valley edges and spread over much larger areas. Deaths at Unzen (1991), Merapi (1994), and Soufriere Hills (1997) have shown the high hazard potential of surges. Surges most commonly form by either entrainment of ambient air at the flow front or interaction between the flow surface and the air. Several aspects of the 1994 flow deposits at Merapi evidence an sudden intensified fragmentation event accompanied by degassing and the release of fines propagating in front of the parental flow, when the avalanche rushed down steep cliffs. This is interpreted as an additional generation mechanism for surges, far away from the source that endanger apparently safe areas. To better constrain the generation mechanisms of such cliff-triggered surges, we perform fall-experiments with Merapi rock samples. We use a setup of a vertical steel pipe with an oven at the top and an wider impact chamber at the base. Cylindrical samples (heated up to maximum 850° C) are attached below a steel stick as additional weight. The total fall height sums up to 3.5 m. Relative pressure changes during impact are measured by a pressure transducer installed at the top of the impact chamber. Data retrieval is controlled by a microphone trigger that is released by the impact. From our preliminary results we infer the generation of a blast-like pressure wave on impact and disintegration. Amplitude and duration of the pressure signal, and degree of fragmentation depend on the temperature of rock samples.

  5. Evidence That Endogenous Somatostatin Inhibits Episodic, but Not Surge, Secretion of LH in Female Sheep.

    Science.gov (United States)

    McCosh, Richard B; Szeligo, Brett M; Bedenbaugh, Michelle N; Lopez, Justin A; Hardy, Steven L; Hileman, Stanley M; Lehman, Michael N; Goodman, Robert L

    2017-06-01

    Two modes of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion are necessary for female fertility: surge and episodic secretion. However, the neural systems that regulate these GnRH secretion patterns are still under investigation. The neuropeptide somatostatin (SST) inhibits episodic LH secretion in humans and sheep, and several lines of evidence suggest SST may regulate secretion during the LH surge. In this study, we examined whether SST alters the LH surge in ewes by administering a SST receptor (SSTR) 2 agonist (octreotide) or antagonist [CYN154806 (CYN)] into the third ventricle during an estrogen-induced LH surge and whether endogenous SST alters episodic LH secretion. Neither octreotide nor CYN altered the amplitude or timing of the LH surge. Administration of CYN to intact ewes during the breeding season or anestrus increased LH secretion and increased c-Fos in a subset GnRH and kisspeptin cells during anestrus. To determine if these stimulatory effects are steroid dependent or independent, we administered CYN to ovariectomized ewes. This SSTR2 antagonist increased LH pulse frequency in ovariectomized ewes during anestrus but not during the breeding season. This study provides evidence that endogenous SST contributes to the control of LH secretion. The results demonstrate that SST, acting through SSTR2, inhibits episodic LH secretion, likely acting in the mediobasal hypothalamus, but action at this receptor does not alter surge secretion. Additionally, these data provide evidence that SST contributes to the steroid-independent suppression of LH pulse frequency during anestrus. Copyright © 2017 Endocrine Society.

  6. Neurokinin-3 Receptor Activation in the Retrochiasmatic Area is Essential for the Full Preovulatory LH Surge in Ewes

    Science.gov (United States)

    Porter, Katrina L.; Hileman, Stanley M.; Hardy, Steven L.; Nestor, Casey C; Lehman, Michael N.; Goodman, Robert L.

    2014-01-01

    Neurokinin B (NKB) is essential for human reproduction and has been shown to stimulate LH secretion in several species, including sheep. Ewes express the neurokinin-3 receptor (NK3R) in the retrochiasmatic area (RCh) and there is one report that placement of senktide, an NK3R agonist, therein stimulates LH secretion that resembles an LH surge in ewes. In this study, we first confirmed that local administration of senktide to the RCh produced a surge-like increase in LH secretion, and then tested the effects of this agonist in two other areas implicated in the control of LH secretion and where NK3R is found in high abundance: the preoptic area (POA) and arcuate nucleus (ARC). Bilateral microimplants containing senktide induced a dramatic surge-like increase in LH when given in the POA similar to that seen with RCh treatment. In contrast, senktide treatment in the ARC resulted in a much smaller, but significant, increase in LH concentrations suggestive of an effect on tonic secretion. The possible role of POA and RCh NK3R activation in the LH surge was next tested by treating ewes with SB222200, an NK3R antagonist, in each area during an E2-induced LH surge. SB222200 in the RCh, but not in the POA, reduced LH surge amplitude by about 40% compared to controls, indicating that NK3R activation in the former region is essential for full expression of the preovulatory LH surge. Based on these data, we propose that NKB actions in the RCh are an important component of the preovulatory LH surge in ewes. PMID:25040132

  7. Short-wave contributions in the storm surge associated with Xynthia, February 2010, western France

    Science.gov (United States)

    Bertin, X.; Li, K.; Roland, A.; Breilf, J. F.; Chaumillon, E.

    2012-04-01

    This study aims to hindcast and analyze the storm surge caused by Xynthia, a mid-latitude storm that severely hit the central part of the Bay of Biscay on the 27-28th of February 2010. This storm surge locally exceeded 1.5 m and peaked at the same time as a high spring tide (Bertin et al., 2012). A new storm surge modeling system was applied, based on the unstructured-grid circulation model SELFE (Zhang and Batista, 2008) and the spectral wave model WWM II (Roland et al., 2008). These two models are fully coupled and parallelized and share the same grid and domain decomposition. The modelling system was implemented over the North-East Atlantic Ocean and the space was discretized using an unstructured grid with a resolution ranging from 30 km in Deep Ocean to 25 m in near shore zones. Such a fine resolution was required to properly represent the surf zone. The modelling system resulted in tidal and wave predictions with errors of the order of 2 and 15%, respectively. The storm surge associated with Xynthia was also well predicted along the Bay of Biscay, with root mean square errors of the order of 0.10 m. Numerical experiments were then performed to analyze the physical processes controlling the development of the storm surge and revealed firstly that the wind caused most of the water level anomaly through an Ekman setup process. The comparison between a wave-dependant and a quadratic parameterization to compute wind stress showed that the storm surge was strongly amplified by the presence of steep and young wind-waves, related to their rapid development in the restricted fetch of the Bay of Biscay. The gradient of wave radiation stress contributed to the whole storm surge by about 0.05 to 0.10 m at the available tide gages. Nevertheless, these gages were located in sheltered harbors and modeling results showed that wave-induced setup locally exceeded 0.5 m in areas more exposed to ocean waves. The unstructured grid is currently being extended inland to simulate

  8. Tide-surge interaction in the English Channel

    Directory of Open Access Journals (Sweden)

    D. Idier

    2012-12-01

    Full Text Available The English Channel is characterised by strong tidal currents and a wide tidal range, such that their influence on surges is expected to be non-negligible. In order to better assess storm surges in this zone, tide-surge interactions are investigated. A preliminary data analysis on hourly surges indicates some preferential times of occurrence of large storm surges at rising tide, especially in Dunkerque. To examine this further, a numerical modelling approach is chosen, based on the 2DH shallow-water model (MARS. The surges are computed both with and without tide interaction. For the two selected events (the November 2007 North Sea and March 2008 Atlantic storms, it appears that the instantaneous tide-surge interaction is seen to be non-negligible in the eastern half of the English Channel, reaching values of 74 cm (i.e. 50% of the same event maximal storm surge in the Dover Strait for the studied cases. This interaction decreases in westerly direction. In the risk-analysis community in France, extreme water levels have been determined assuming skew surges and tide as independent. The same hydrodynamic model is used to investigate this dependence in the English Channel. Simple computations are performed with the same meteorological forcing, while varying the tidal amplitude, and the skew surge differences DSS are analysed. Skew surges appear to be tide-dependent, with negligible values of DSS (<0.05 m over a large portion of the English Channel, although reaching several tens of centimetres in some locations (e.g. the Isle of Wight and Dover Strait.

  9. Will oscillating wave surge converters survive tsunamis?

    Directory of Open Access Journals (Sweden)

    L. O’Brien

    2015-07-01

    Full Text Available With an increasing emphasis on renewable energy resources, wave power technology is becoming one of the realistic solutions. However, the 2011 tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed, creating large destructive waves. The question posed here is whether an oscillating wave surge converter (OWSC could withstand the force of an incoming tsunami. Several tools are used to provide an answer: an analytical 3D model developed within the framework of linear theory, a numerical model based on the non-linear shallow water equations and empirical formulas. Numerical results show that run-up and draw-down can be amplified under some circumstances, leading to an OWSC lying on dry ground!

  10. Predicting Storm Surges: Chaos, Computational Intelligence, Data Assimilation, Ensembles

    NARCIS (Netherlands)

    Siek, M.B.L.A.

    2011-01-01

    Accurate predictions of storm surge are of importance in many coastal areas. This book focuses on data-driven modelling using methods of nonlinear dynamics and chaos theory for predicting storm surges. A number of new enhancements are presented: phase space dimensionality reduction, incomplete time

  11. Predicting Storm Surges : Chaos, Computational Intelligence, Data Assimilation, Ensembles

    NARCIS (Netherlands)

    Siek, M.B.L.A.

    2011-01-01

    Accurate predictions of storm surge are of importance in many coastal areas. This book focuses on data-driven modelling using methods of nonlinear dynamics and chaos theory for predicting storm surges. A number of new enhancements are presented: phase space dimensionality reduction, incomplete time

  12. Overview and Design Considerations of Storm Surge Barriers

    NARCIS (Netherlands)

    Mooyaart, L.F.; Jonkman, S.N.

    2017-01-01

    The risk of flooding in coastal zones is expected to increase due to sea level rise and economic development. In larger bays, estuaries, and coastal waterways, storm surge barriers can be constructed to temporarily close off these systems during storm surges to provide coastal flood protection.

  13. Harmful effects of lightning surge discharge on communications terminal equipments

    Science.gov (United States)

    Liang, Sisi; Xu, Xiaoying; Tao, Zhigang; Dai, Yanling

    2013-03-01

    The interference problem of lightning surges on electronic and telecommunication products were examined, and a series of experiments were conducted to analyze the failure situations to find out the mechanisms of failures caused by the lightning surge. In addition, the ways in which lightning surges damaged equipment were deduced. It was found that failure positions were scattered and appeared in groups, and most of them were ground discharge. Internet access transformer had high withstand-voltage under the lightning pulse, and the lightning surge seldom passed through the internet access transformer. The lightning current can release to the ground via the computer network adapter of the terminal user. The study will help to improve the performance of lightning surge protection circuit and protection level.

  14. Coastal Storm Surge Analysis: Storm Surge Results. Report 5: Intermediate Submission No. 3

    Science.gov (United States)

    2013-11-01

    storm surge stillwater elevations for all Flood Insurance Studies in the study area, and serve as the basis for new coastal hazard analyses and...parametric relation- ships, and do not assume parameter independence. Thus, the EST is “distribution free” and nonparametric . EST is a statistical...simulations is used to develop frequency relationships for any storm response as a function of input parameters that are descriptive of the storm

  15. Exploring Water Level Sensitivity for Metropolitan New York during Sandy (2012 Using Ensemble Storm Surge Simulations

    Directory of Open Access Journals (Sweden)

    Brian A. Colle

    2015-06-01

    Full Text Available This paper describes storm surge simulations made for Sandy (2012 for the Metropolitan New York (NYC area using the Advanced Circulation (ADCIRC model forced by the Weather Research and Forecasting (WRF model. The atmospheric forecast uncertainty was quantified using 11-members from an atmospheric Ensemble Kalman Filter (EnKF system. A control WRF member re-initialized every 24 h demonstrated the capability of the WRF-ADCIRC models to realistically simulate the 2.83 m surge and 4.40 m storm tide (surge + astronomical tide above mean lower low water (MLLW for NYC. Starting about four days before landfall, an ensemble of model runs based on the 11 “best” meteorological predictions illustrate how modest changes in the track (20–100 km and winds (3–5 m s−1 of Sandy approaching the New Jersey coast and NYC can lead to relatively large (0.50–1.50 m storm surge variations. The ensemble also illustrates the extreme importance of the timing of landfall relative to local high tide. The observed coastal flooding was not the worst case for this particular event. Had Sandy made landfall at differing times, locations and stages of the tide, peak water levels could have been up to 0.5 m higher than experienced.

  16. Developmental programming: postnatal steroids complete prenatal steroid actions to differentially organize the GnRH surge mechanism and reproductive behavior in female sheep.

    Science.gov (United States)

    Jackson, Leslie M; Mytinger, Andrea; Roberts, Eila K; Lee, Theresa M; Foster, Douglas L; Padmanabhan, Vasantha; Jansen, Heiko T

    2013-04-01

    In female sheep, estradiol (E2) stimulates the preovulatory GnRH/LH surge and receptive behavior, whereas progesterone blocks these effects. Prenatal exposure to testosterone disrupts both the positive feedback action of E2 and sexual behavior although the mechanisms remain unknown. The current study tested the hypothesis that both prenatal and postnatal steroids are required to organize the surge and sex differences in reproductive behavior. Our approach was to characterize the LH surge and mating behavior in prenatally untreated (Control) and testosterone-treated (T) female sheep subsequently exposed to one of three postnatal steroid manipulations: endogenous E2, excess E2 from a chronic implant, or no E2 due to neonatal ovariectomy (OVX). All females were then perfused at the time of the expected surge and brains processed for estrogen receptor and Fos immunoreactivity. None of the T females exposed postnatally to E2 exhibited an E2-induced LH surge, but a surge was produced in five of six T/OVX and all Control females. No surges were produced when progesterone was administered concomitantly with E2. All Control females were mounted by males, but significantly fewer T females were mounted by a male, including the T/OVX females that exhibited LH surges. The percentage of estrogen receptor neurons containing Fos was significantly influenced in a brain region-, developmental stage-, and steroid-specific fashion by testosterone and E2 treatments. These findings support the hypothesis that the feedback controls of the GnRH surge are sensitive to programming by prenatal and postnatal steroids in a precocial species.

  17. Environmental fatigue evaluation for Kori unit 1 surge line

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jun Seog [Korea Electric Power Research Institue, Daejeon (Korea, Republic of); Park, Chi Yong; Kang, Seon Ye [Korea Power Engineering Company, Inc., Yongin (Korea, Republic of)

    2009-07-01

    The original design of Kori Unit 1 did not consider the thermal stratification phenomena in the surge line piping and the insurge / outsurge out of limit in the pressurizer lower head during plant heat up and cooldown condition. For the plant life extension over 20 years, the metal fatigue evaluation considering the effects of reactor water environment was performed to determine the impact of the insurge / outsurge out of transients and thermal stratification transients, in conjunction with design transient effects, on the environmental fatigue usage factors at the critical locations of the surge line and pressurizer surge nozzle. In this paper, the effects of the environmental fatigue were evaluated and discussed by confining to the thermal stratification transients in the surge line and insurge / outsurge transients in the pressurizer surge nozzle. Also, the use of fatigue life correction factor to incorporate the effects of environment into the ASME Code fatigue evaluation for the surge line piping and pressurizer surge nozzle was discussed in this paper.

  18. Surge dynamics on Bering Glacier, Alaska, in 2008–2011

    Directory of Open Access Journals (Sweden)

    M. Braun

    2012-11-01

    Full Text Available A surge cycle of the Bering Glacier system, Alaska, is examined using observations of surface velocity obtained using synthetic aperture radar (SAR offset tracking, and elevation data obtained from the University of Alaska Fairbanks LiDAR altimetry program. After 13 yr of quiescence, the Bering Glacier system began to surge in May 2008 and had two stages of accelerated flow. During the first stage, flow accelerated progressively for at least 10 months and reached peak observed velocities of ~ 7 m d−1. The second stage likely began in 2010. By 2011 velocities exceeded 9 m d−1 or ~ 18 times quiescent velocities. Fast flow continued into July 2011. Surface morphology indicated slowing by fall 2011; however, it is not entirely clear if the surge is yet over. The quiescent phase was characterized by small-scale acceleration events that increased driving stresses up to 70%. When the surge initiated, synchronous acceleration occurred throughout much of the glacier length. Results suggest that downstream propagation of the surge is closely linked to the evolution of the driving stress during the surge, because driving stress appears to be tied to the amount of resistive stress provided by the bed. In contrast, upstream acceleration and upstream surge propagation is not dependent on driving stress evolution.

  19. Spatial Variation in Storm Surge in the Strait of Georgia

    Science.gov (United States)

    Soontiens, N. K.; Allen, S. E.; Latornell, D.; Le Souef, K.; Machuca, I.

    2014-12-01

    The Strait of Georgia is a strongly stratified, deep body of water located between Vancouver Island and the mainland of British Columbia and is connected to the Pacific Ocean via the Strait of Juan de Fuca to the south and Johnstone Strait to the north. It is on average 220 km in length and 30 km wide and its maximum depth is 420 m. During the winter months, coastal communities in the Strait of Georgia are at risk to flooding caused by storm surges, a natural hazard that occurs when a strong wind storm with low atmospheric pressure coincides with an unusually high tide. This study presents storm surge hindcasts of significant events between 2006 and 2009 using a numerical model of the Straits of Georgia, Juan de Fuca, Johnstone and Puget Sound (together the Salish Sea). The model is based on the Nucleus for European Modelling of the Ocean (NEMO) in a regional configuration. Realistic stratification is produced by including input from the surrounding rivers. A discussion on the sensitivity of modelled surge amplitude to open boundary conditions and atmospheric forcing will be presented. As barotropic models have previously shown, the surge entering the domain from the Pacific Ocean contributes most significantly. Surge amplitudes are found to be greater within the Strait of Georgia than those in the Strait of Juan de Fuca. Local wind patterns cause spatial variations in the strength of the surge in the Strait of Georgia, generally leading to stronger surges on the Mainland side of the Strait.

  20. On hurricane parametric wind and applications in storm surge modeling

    Science.gov (United States)

    Lin, Ning; Chavas, Daniel

    2012-05-01

    This study revisits the parametric modeling of the hurricane surface wind field composed of the storm vortex and the environmental background flow. First, we investigate the parametric representation of the surface background wind by analyzing its empirical relationship with storm movement. A marked deceleration and counter-clockwise rotation of the surface background wind from the storm translation vector is detected, a result predicted by the Ekman theory but rarely applied in wind and surge modeling. Then, we examine the various parameters used to model the wind field and, through numerical simulations, quantify their induced uncertainties in the extreme wind and surge estimates at two coastal sites. Our analyses show that, over the range of accepted values and methods in the literature, the local wind and surge estimates are most sensitive to uncertainties in the surface wind reduction factor and storm wind profile but less sensitive to uncertainties in other wind parameters, such as inflow angle and surface background wind (varying in the observed range). The surge is more sensitive than the wind to uncertainties in the wind parameters, and these sensitivities are comparable to the sensitivity of the surge to the uncertainty in the sea surface drag coefficient. We also find that some commonly used wind parameters unsupported by theory or observations can induce significant errors in the wind and surge estimates. The results of this study provide new insights and references for future hurricane wind and surge analysis.

  1. Involvement of salsolinol in the suckling-induced oxytocin surge in sheep.

    Science.gov (United States)

    Górski, K; Misztal, T; Marciniak, E; Zielińska-Górska, M K; Fülöp, F; Romanowicz, K

    2017-04-01

    During lactation, the main surge of oxytocin is induced by a suckling stimulus. Previous studies have shown that salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline), a dopamine-derived compound, stimulates both the synthesis and the release of oxytocin in lactating sheep. The objective of the present study was to verify the hypothesis that salsolinol is involved in the mechanism that generates the oxytocin surge that occurs during suckling. Thus, a structural analogue of salsolinol, 1-methyl-3,4-dihydroisoquinoline (1MeDIQ), known to antagonize some of its actions, was infused into the third ventricle of the brain of lactating sheep nursing their offspring. Serial 30-min infusion of 1MeDIQ (4 × 60 μg/60 μL) or vehicle were administered at 30-min interval from 10 AM to 2 PM. The experimental period in every ewe consisted of a nonsuckling period (10 AM-12 PM) and a suckling period (12 PM-2 PM). Blood samples were collected every 10 min, to measure plasma oxytocin concentration by RIA. In control sheep, oxytocin surges of high amplitude were observed during the suckling period. The oxytocin surges induced by suckling were significantly (P oxytocin release, before suckling. Furthermore, oxytocin release, as measured by the area under the hormone response curve (AUC), was significantly decreased by the administration of 1MeDIQ during the suckling period. This study shows that elimination of the effect of salsolinol within the central nervous system of lactating sheep attenuates the oxytocin surge induced by suckling. Therefore, salsolinol may be an important factor in the oxytocin-stimulating pathway in lactating mammals. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Ultra High Voltage Surge Waveforms Measurement Using an Optical Transducer

    Directory of Open Access Journals (Sweden)

    Francisco G. PEÑA-LECONA

    2010-05-01

    Full Text Available Ultra high voltage surge waveforms measurement by means of a portable optical transducer is presented. The sensor system uses a transducer element based on the longitudinal electro-optic effect with a double pass configuration to obtain a better sensitivity. The transducer head is allocated to one meter of distance from the generating element of electric field and it is able to measure waveform surges from 515 kV up to 1090 kV with fast response. It is demonstrated that the telemetry of ultra high voltage surge waveforms can be successfully done by means of this proposed optical transducer.

  3. Snapshot Provisioning of Cloud Application Stacks to Face Traffic Surges

    OpenAIRE

    Pewo Fouomene, Daniel; Rouvoy, Romain; Seinturier, Lionel

    2013-01-01

    Traffic surges, like the Slashdot effect, occur when a web application is overloaded by a huge number of requests, potentially leading to unavailability. Unfortunately, such traffic variations are generally totally unplanned, of great amplitude, within a very short period, and a variable delay to return to a normal regime. In this report, we introduce PeakForecast as an elastic middleware solution to detect and absorb a traffic surge. In particular, PeakForecast can, from a trace of queries r...

  4. Management of Surge in Extracorporeal Membrane Oxygenation Transport.

    Science.gov (United States)

    Salna, Michael; Chicotka, Scott; Biscotti, Mauer; Agerstrand, Cara; Liou, Peter; Ginsburg, Mark; Oommen, Roy; Sonett, Joshua R; Brodie, Daniel; Bacchetta, Matthew

    2017-11-23

    Transporting patients receiving extracorporeal membrane oxygenation (ECMO) support is safe and reliable with a dedicated program and established management protocols. As our program has grown, our teams have had to adapt to manage surges in transport volume while maintaining patient safety. We assessed the outcomes at peak use of our ECMO transport services during surges. We conducted a single-center retrospective review of all patients transported to our institution while supported with ECMO from September 2008 to September 2016. Survival to discharge was the primary outcome. Surge patients were defined as those transported during months with at least 8 transports or patients transported within 24 hours of another patient in nonsurge months. From 2008 to 2016, 222 patients were transported to our institution while supported with ECMO. Baseline characteristics and indices of disease severity were comparable between surge and nonsurge patients. Of the 84 patients transported during surges, 59 surge patients (70%) survived to hospital discharge vs 86 (63%) of nonsurge patients (p = 0.31). Multivariable logistic regression showed that age and APACHE II (Acute Physiology and Chronic Health Evaluation) severity index score were predictors of in-hospital death (p surge was not (odds ratio, 0.91; 95% confidence interval, 0.46 to 1.80; p = 0.79). Patient safety and clinical outcomes can be maintained during surges in ECMO transport volume if the ECMO program has developed plans for handling transient increases in volume and considers staff fatigue and burnout. Standardizing interhospital communication, patient selection, and management protocols are critical to maintaining quality of care. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Developments in Surge Research Priorities: A Systematic Review of the Literature Following the Academic Emergency Medicine Consensus Conference, 2007-2015.

    Science.gov (United States)

    Morton, Melinda J; DeAugustinis, Matthew L; Velasquez, Christina A; Singh, Sonal; Kelen, Gabor D

    2015-11-01

    In 2006, Academic Emergency Medicine (AEM) published a special issue summarizing the proceedings of the AEM consensus conference on the "Science of Surge." One major goal of the conference was to establish research priorities in the field of "disasters" surge. For this review, we wished to determine the progress toward the conference's identified research priorities: 1) defining criteria and methods for allocation of scarce resources, 2) identifying effective triage protocols, 3) determining decision-makers and means to evaluate response efficacy, 4) developing communication and information sharing strategies, and 5) identifying methods for evaluating workforce needs. Specific criteria were developed in conjunction with library search experts. PubMed, Embase, Web of Science, Scopus, and the Cochrane Library databases were queried for peer-reviewed articles from 2007 to 2015 addressing scientific advances related to the above five research priorities identified by AEM consensus conference. Abstracts and foreign language articles were excluded. Only articles with quantitative data on predefined outcomes were included; consensus panel recommendations on the above priorities were also included for the purposes of this review. Included study designs were randomized controlled trials, prospective, retrospective, qualitative (consensus panel), observational, cohort, case-control, or controlled before-and-after studies. Quality assessment was performed using a standardized tool for quantitative studies. Of the 2,484 unique articles identified by the search strategy, 313 articles appeared to be related to disaster surge. Following detailed text review, 50 articles with quantitative data and 11 concept papers (consensus conference recommendations) addressed at least one AEM consensus conference surge research priority. Outcomes included validation of the benchmark of 500 beds/million of population for disaster surge capacity, effectiveness of simulation- and Internet

  6. Seasonal autoregressive modeling of a skew storm surge series

    Science.gov (United States)

    Weiss, Jérôme; Bernardara, Pietro; Andreewsky, Marc; Benoit, Michel

    Autoregressive (AR) models have been widely used in several geophysical applications, as they represent a simple and practical option for modeling stochastic series. In this paper, we show that AR models can be adapted and are useful for the description of skew surge (i.e., a surge occurring at the time of a high tide) series. Namely, seasonal AR models of skew surge series are built on 35 sites located along the coasts of the European Atlantic Ocean, the English Channel and the Southern part of the North Sea. These models are presented and discussed. The estimation of the distribution of the residuals, modeled using a Normal Inverse Gaussian (NIG) distribution, is also discussed. AR models are advantageous for a number of reasons: (i) they provide information on the correlation length of the surge phenomena, (ii) they can be used to forecast short-term surge occurrences based on a limited set of past observations and (iii) they provide plausible information about longer series, which may have larger extremes than what is observed, permitting a statistical description of simulated extremes. These three characteristics and benefits are examined and discussed for a selected site, the Saint-Nazaire harbor (France), with respect to the storm surge that occurred during the Xynthia storm of February 2010.

  7. Performance of Surge Arrester Installation to Enhance Protection

    Directory of Open Access Journals (Sweden)

    Mbunwe Muncho Josephine

    2017-01-01

    Full Text Available The effects of abnormal voltages on power system equipment and appliances in the home have raise concern as most of the equipments are very expensive. Each piece of electrical equipment in an electrical system needs to be protected from surges. To prevent damage to electrical equipment, surge protection considerations are paramount to a well designed electrical system. Lightning discharges are able to damage electric and electronic devices that usually have a low protection level and these are influenced by current or voltage pulses with a relatively low energy, which are induced by lightning currents. This calls for proper designed and configuration of surge arresters for protection on the particular appliances. A more efficient non-linear surge arrester, metal oxide varistor (MOV, should be introduced to handle these surges. This paper shows the selection of arresters laying more emphasis on the arresters for residential areas. In addition, application and installation of the arrester will be determined by the selected arrester. This paper selects the lowest rated surge arrester as it provides insulation when the system is under stress. It also selected station class and distribution class of arresters as they act as an open circuit under normal system operation and to bring the system back to its normal operation mode as the transient voltage is suppressed. Thus, reduces the risk of damage, which the protection measures can be characterized, by the reduction value of the economic loss to an acceptable level.

  8. Hurricane waves on Storm Surges in Coastal Zone

    Science.gov (United States)

    Wu, C.

    2005-05-01

    During a tropical storm, high winds and low pressure generate abnormal sea water levels and currents. We present a time series of 48 hours water levels combining wave effects on surges during hurricane Opal (1995). The offshore hurricane ocean wave is modeled by a recent parametric ocean wave model using the best track data. The post-storm meteorological input data are applied to the calculation of surges and storm waves. A scheme is used to simulate the effects of wave-surges near the coast: the time varying surges is obtained first and then the modified mean water level is used for coastal wave calculations. The high water levels at the gauge station and on-site debris line are collected for model comparison. The hurricane waves and coastal waves are calculated near the eye center and on the beach slope, where the waves break and produce a mean free surface wave set-up. We examined the maximum wave set-ups at the shoreline, the wave run-up on the beach, adding up the storm surges and predicted tides at the station. It was found that the inland flooding is the combined results of storm surges elevating the water level, causing the wave breaking further landward and a higher wave run-up. The accuracy of hurricane waves is significant to the determination of inundation zone.

  9. Kisspeptin-GPR54 signaling is essential for preovulatory gonadotropin-releasing hormone neuron activation and the luteinizing hormone surge.

    Science.gov (United States)

    Clarkson, Jenny; d'Anglemont de Tassigny, Xavier; Moreno, Adriana Santos; Colledge, William H; Herbison, Allan E

    2008-08-27

    Kisspeptin and its receptor GPR54 have recently been identified as key signaling partners in the neural control of fertility in animal models and humans. The gonadotropin-releasing hormone (GnRH) neurons represent the final output neurons of the neural network controlling fertility and are suspected to be the primary locus of kisspeptin-GPR54 signaling. Using mouse models, the present study addressed whether kisspeptin and GPR54 have a key role in the activation of GnRH neurons to generate the luteinizing hormone (LH) surge responsible for ovulation. Dual-label immunocytochemistry experiments showed that 40-60% of kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3V) expressed estrogen receptor alpha and progesterone receptors. Using an ovariectomized, gonadal steroid-replacement regimen, which reliably generates an LH surge, approximately 30% of RP3V kisspeptin neurons were found to express c-FOS in surging mice compared with 0% in nonsurging controls. A strong correlation was found between the percentage of c-FOS-positive kisspeptin neurons and the percentage of c-FOS-positive GnRH neurons. To evaluate whether kisspeptin and/or GPR54 were essential for GnRH neuron activation and the LH surge, Gpr54- and Kiss1-null mice were examined. Whereas wild-type littermates all exhibited LH surges and c-FOS in approximately 50% of their GnRH neurons, none of the mutant mice from either line showed an LH surge or any GnRH neurons with c-FOS. These observations provide the first evidence that kisspeptin-GPR54 signaling is essential for GnRH neuron activation that initiates ovulation. This broadens considerably the potential roles and therapeutic possibilities for kisspeptin and GPR54 in fertility regulation.

  10. Lack of pulse and surge modes and glutamatergic stimulation of luteinising hormone release in Kiss1 knockout rats.

    Science.gov (United States)

    Uenoyama, Y; Nakamura, S; Hayakawa, Y; Ikegami, K; Watanabe, Y; Deura, C; Minabe, S; Tomikawa, J; Goto, T; Ieda, N; Inoue, N; Sanbo, M; Tamura, C; Hirabayashi, M; Maeda, K-I; Tsukamura, H

    2015-03-01

    Kisspeptin, encoded by the Kiss1 gene, has attracted attention as a key candidate neuropeptide in controlling puberty and reproduction via regulation of gonadotrophin-releasing hormone (GnRH) secretion in mammals. Pioneer studies with Kiss1 or its cognate receptor Gpr54 knockout (KO) mice showed the indispensable role of kisspeptin-GPR54 signalling in the control of animal reproduction, although detailed analyses of gonadotrophin secretion, especially pulsatile and surge-mode of luteinising hormone (LH) secretion, were limited. Thus, in the present study, we have generated Kiss1 KO rats aiming to evaluate a key role of kisspeptin in governing reproduction via pulse and surge modes of GnRH/LH secretion. Kiss1 KO male and female rats showed a complete suppression of pulsatile LH secretion, which is responsible for folliculogenesis and spermatogenesis, and an absence of puberty and atrophic gonads. Kiss1 KO female rats showed no spontaneous LH/follicle-stimulating hormone surge and an oestrogen-induced LH surge, suggesting that the GnRH surge generation system, which is responsible for ovulation, does not function without kisspeptin. Furthermore, challenge of major stimulatory neurotransmitters, such as monosodium glutamate, NMDA and norepinephrine, failed to stimulate LH secretion in Kiss1 KO rats, albeit they stimulated LH release in wild-type controls. Taken together, the results of the present study confirm that kisspeptin plays an indispensable role in generating two modes (pulse and surge) of GnRH/gonadotrophin secretion to regulate puberty onset and normal reproductive performance. In addition, the present study suggests that kisspeptin neurones play a critical role as a hub integrating major stimulatory neural inputs to GnRH neurones, using newly established Kiss1 KO rats, which serve as a useful model for detailed analysis of hormonal profiles. © 2015 British Society for Neuroendocrinology.

  11. Sampling plans for lightning surges test program. Final report, May 1976--January 1977

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-03-01

    Results are presented of a study undertaken to determine how to measure and evaluate lightning-induced surges on power distribution lines. The study centered on the following basic tasks: prediction of ligntning phenomena; selection and characterization of instrument placement sites; determination of appropriate number of instruments; determination of instrument storage and data collection requirements; and recommendations for future efforts. It was concluded that 400 lightning surge recorders are needed for accummulating basic test data; 250 additional instruments are recommended for obtaining supplementary data; the instruments should be placed throughout the US with careful control of site selection and instrument installation; each instrument should be able to store one year's data; and this proposed field study is only the first step in achieving an understanding of the lightning protection cost-benefit problem. (LCL)

  12. Thermal Stratification Analyses for Arrangements of Pressurizer Surge Line

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Da Yong; Choe, Yoon Jae; Yune, Seok Jeong; Kim, Eun Kee [KEPCO Engineering and Construction Company., Inc., Daejeon (Korea, Republic of)

    2014-10-15

    The thermal stratification may influence the integrity of pipe. In a Nuclear Power Plant (NPP), some safety related pipes connected to reactor coolant system are known to be potentially susceptible to fatigue failure resulting from thermal stratification. According to the international operating experiences, those are the pressurizer (PZR) surge line, the injection pipes of the emergency core cooling system and residual heat removal lines. In particular, during normal operation, the thermal stratification in PZR surge line can occur differently from the other two lines because hotter water flowing from the PZR to the hot leg flows over a layer of colder water through the PZR surge line. For this reason, it is considered that the thermal stratification in PZR surge line has been one of the significant issues for structural integrity of NPP. Therefore, this study focuses on new arrangements of PZR surge line for reducing the thermal stratification during normal operation of NPP and analyzes what new arrangements can reduce the effect of thermal stratification through CFD calculation using FLUENT Ver.15. This study was suggests what new arrangement can reduce the effect of thermal stratification compared with the current arrangement of NPPs by using CFD analyses. The results show that more global thermal stratification occurred in BASE arrangement throughout the PZR surge line compared with other arrangements. In addition, the increase of flow velocity from PZR resulted in the increase of maximum temperature difference between the top and bottom sides and the reduction of thermal stratification region. The reason is that the buoyancy force is weakened by other forces such as fluid vortex, velocity increase due to the slope of surge line and turbulent penetration.

  13. The nocturnal thyroid-stimulating hormone surge is absent in overt, present in mild primary and equivocal in central hypothyroidism

    NARCIS (Netherlands)

    Adriaanse, R.; Romijn, J. A.; Endert, E.; Wiersinga, W. M.

    1992-01-01

    The nocturnal TSH surge was studied in controls, in 34 patients with hypothalamic/pituitary disease and in 21 patients with primary hypothyroidism. It was absent in 5/12 hypothyroid patients and in 5/22 euthyroid patients with hypothalamic/pituitary disease (42% vs 23%, NS). Central hypothyroidism

  14. Methodology for surge pressure evaluation in a water injection system

    Energy Technology Data Exchange (ETDEWEB)

    Meliande, Patricia; Nascimento, Elson A. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Civil; Mascarenhas, Flavio C.B. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Hidraulica Computacional; Dandoulakis, Joao P. [SHELL of Brazil, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Predicting transient effects, known as surge pressures, is of high importance for offshore industry. It involves detailed computer modeling that attempts to simulate the complex interaction between flow line and fluid in order to ensure efficient system integrity. Platform process operators normally raise concerns whether the water injection system is adequately designed or not to be protected against possible surge pressures during sudden valve closure. This report aims to evaluate the surge pressures in Bijupira and Salema water injection systems due to valve closure, through a computer model simulation. Comparisons among the results from empirical formulations are discussed and supplementary analysis for Salema system were performed in order to define the maximum volumetric flow rate for which the design pressure was able to withstand. Maximum surge pressure values of 287.76 bar and 318.58 bar, obtained in Salema and Bijupira respectively, using empirical formulations have surpassed the operating pressure design, while the computer model results have pointed the greatest surge pressure value of 282 bar in Salema system. (author)

  15. Surge Recovery Techniques for the Tevatron Cold Compressors

    Science.gov (United States)

    Martinez, A.; Klebaner, A. L.; Makara, J. N.; Theilacker, J. C.

    2006-04-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, made by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations. The compressor is designed to pump 60 g/s of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/s and operating speeds between 40 and 95 krpm. Since initial commissioning in 1993, Tevatron transient conditions such as quench recovery have led to multiple-location machine trips as a result of the cold compressors entering the surge regime. Historically, compressors operating at lower inlet pressures and higher speeds have been especially susceptible to these machine trips and it was not uncommon to have multiple compressor trips during large multiple-house quenches. In order to cope with these events and limit accelerator down time, surge recovery techniques have been implemented in an attempt to prevent the compressors from tripping once the machine entered this surge regime. This paper discusses the different methods of surge recovery that have been employed. Data from tests performed at the Cryogenic Test Facility at Fermilab as well as actual Tevatron operational data were utilized. In order to aid in the determination of the surge region, a full mapping study was undertaken to characterize the entire pressure field of the cold compressor. These techniques were then implemented and tested at several locations in the Tevatron with some success.

  16. Storm surge propagation in Galveston Bay during Hurricane Ike

    Science.gov (United States)

    Rego, João L.; Li, Chunyan

    2010-09-01

    We studied Hurricane Ike's storm surge along the Texas-Louisiana coast using the fully nonlinear Finite-Volume Coastal Ocean Model (FVCOM, by Chen et al., 2003) with a high-resolution unstructured mesh. The model was validated with USGS surge data collected during Hurricane Ike. This study focused on 1) how the surge wave propagates into and within Galveston Bay and 2) the importance of the bay's barrier system. Ike's coastal surge propagated alongshore due east towards Louisiana, partly because of Bolivar Peninsula, which, together with Galveston Island, provided a barrier protecting the bay. In the upper bay, a west-east oscillation of water surface gradient of about 0.08 m/km was found and studied. We then varied Bolivar Peninsula's topography for different simulations, examining the role of barrier islands on surge propagation into the bay. Results suggest that when the Peninsula's height (or volume) was reduced to about 45% of the original, with two breaches, the bay was exposed to dangerously high water levels almost as much as those if the Peninsula was leveled to just 0.05 m above the Mean Sea Level, underlining the nonlinear nature of this bay-barrier system.

  17. Cold surge: a sudden and spatially varying threat to health?

    Science.gov (United States)

    Wu, Pei-Chih; Chen, Vivian Yi-Ju; Su, Huey-Jen

    2011-01-01

    While cold surge is one of the most conspicuous features of the winter monsoon in East Asia, its impact on human health remains underexplored. Based on the definition by the Central Weather Bureau in Taiwan, we identified four cold surges between 2000 and 2003 and collected the cardiovascular disease mortality data two weeks before and two weeks after these events. We attempted to answer the following research questions: 1) whether the cold surges impose an adverse and immediate effect on cardiovascular mortality; 2) whether the people living in temperate zones have a higher tolerance of extreme temperature drop than do those in the subtropics. With geographic weighting techniques, we not only found that the cardiovascular disease mortality rates increased significantly after the cold surges, but also discovered a spatially varying pattern of tolerance to cold surges. Even within a small study area such as Taiwan, human reaction to severe weather drop differs across space. Needless to say, in the U.S., these findings should be considered in redirecting policy to address populations living in warm places when extreme temperature drops occur. PMID:19162302

  18. Performance and Adaptive Surge-Preventing Acceleration Prediction of a Turboshaft Engine under Inlet Flow Distortion

    Directory of Open Access Journals (Sweden)

    Cao Dalu

    2017-01-01

    Full Text Available The intention of this paper is to research the inlet flow distortion influence on overall performance of turboshaft engine and put forward a method called Distortion Factor Item (DFI to improve the fuel supply plan for surge-preventing acceleration when turboshaft engine suddenly encounters inlet flow distortion. Based on the parallel compressor theory, steady-state and transition-state numerical simulation model of turboshaft engine with sub-compressor model were established for researching the influence of inlet flow distortion on turboshaft engine. This paper made a detailed analysis on the compressor operation from the aspects of performance and stability, and then analyzed the overall performance and dynamic response of the whole engine under inlet flow distortion. Improved fuel supply plan with DFI method was applied to control the acceleration process adaptively when encountering different inlet flow distortion. Several simulation examples about extreme natural environments were calculated to testify DFI method’s environmental applicability. The result shows that the inlet flow distortion reduces the air inflow and decreases the surge margin of compressor, and increase the engine exhaust loss. Encountering inlet flow distortion has many adverse influences such as sudden rotor acceleration, turbine inlet temperature rise and power output reduction. By using improved fuel supply plan with DFI, turboshaft engine above-idle acceleration can avoid surge effectively under inlet flow distortion with environmental applicability.

  19. Hybrid complexity modelling of changes to estuary morphology, hydrodynamics and tidal surge water levels at 10 to 200 year timescales.

    Science.gov (United States)

    French, J.; Burningham, H.

    2016-12-01

    Extreme coastal flooding is expected to increase with climate change, especially in estuaries susceptible to tidal surges. Estuary hydrodynamics are well understood and models can predict spatial variation in tide and surge water levels with skill. However, estuary morphological change alters the pathway between sources of flood risk (tides, surges) and receptors (humans, assets, activities) in vulnerable areas. Our ability to predict morphological change at timescales relevant to climate change remains limited, and this hinders quantitative assessment of changing flood risk. Reductionist hydrodynamic and sediment transport models tend to perform poorly at longer timescales and estuary morphodynamics are increasingly modelled using more `synthesist' approaches to capture landform behaviour at 10 to 100+ year timescales. However, non-linear interaction between tides and morphology means that it is useful to retain hydrodynamic complexity to resolve feedbacks between morphological change and tide/surge propagation. This paper presents a new approach to estuary morphological evolution that combines 1D simulation of tidal hydrodynamics with parameterised 2D representation of intertidal sedimentation and erosion under the influence of fetch-limited waves (Estuary Spatial Landscape Evolution Model; ESTEEM). ESTEEM is used in combination with a 2D shallow water equation model (Telemac2D) to simulate changes in 100 to 200-year flood levels that include changes in morphology due to continuing natural sedimentary processes and realignment of flood defences to accommodate sea-level rise. Results for two UK estuaries indicate that hydrodynamics and surge levels change only slightly with present defences in place. Flood defence realignment results in step-changes to the morphology and significant effects on tide and surge water levels. Evolution of the altered morphology tends to counter the hydrodynamic impact, but is sensitive to wind climate, which strongly controls

  20. The Role of Kisspeptin and RFRP-3 Neurons in the Circadian-Timed Preovulatory Luteinizing Hormone Surge

    Science.gov (United States)

    Khan, Azim R.; Kauffman, Alexander S.

    2011-01-01

    Many aspects of female reproduction often require intricate timing, ranging from temporal regulation of reproductive hormone secretion to the precise timing of sexual behavior. In particular, in rodents and other species, ovulation is triggered by a surge in pituitary luteinizing hormone (LH) secretion that is governed by a complex interaction between circadian signals arising in the hypothalamus and ovarian-derived estradiol signals acting on multiple brain circuitries. These circadian and hormonal pathways converge to stimulate a precisely-timed surge in gonadotropin-releasing hormone (GnRH) release (i.e., positive feedback), thereby triggering the preovulatory LH surge. Reflecting its control by afferent circadian signals, the preovulatory LH surge occurs at a specific time of day, typically late afternoon in nocturnal rodents. Although the specific mechanisms mediating the hormonal and circadian regulation of GnRH/LH release have remained poorly understood, recent findings now suggest that estradiol and circadian signals govern specific reproductive neuropeptide circuits in the hypothalamus, including the newly-identified kisspeptin and RFamide-related peptide-3 (RFRP-3) neuronal populations. Neurons producing kisspeptin, the protein product of the Kiss1 gene, and RFRP-3 have been shown to provide excitatory and inhibitory input to GnRH neurons, respectively, and are also influenced by sex steroid and circadian signals. Here, we integrate classic and recent findings to form a new working model for the neuroendocrine regulation of the circadian-timed preovulatory LH surge in rodents. This model proposes kisspeptin and RFRP-3 neuronal populations as key nodal points for integrating and transducing circadian and hormonal signals to the reproductive axis, thereby governing the precisely-timed LH surge. PMID:21592236

  1. Negative feedback as an obligatory antecedent to the estradiol-induced luteinizing hormone surge in ovariectomized pigs.

    Science.gov (United States)

    Kesner, J S; Price-Taras, E A; Kraeling, R R; Rampacek, G B; Barb, C R

    1989-09-01

    In ovariectomized pigs, estradiol treatment induces a preovulatory-like luteinizing hormone (LH) surge, but only after serum LH concentrations are suppressed for 48 h. This inhibition of LH release is attributable in large part to inhibition of gonadotropin-releasing hormone (GnRH) release. The present report examines the dependency of the estradiol-induced LH surge on this preceding phase of negative feedback. Ten ovariectomized gilts were given an i.m. injection of estradiol benzoate (10 micrograms/kg BW). Beginning at the time of estradiol treatment, 5 of these gilts received 1-microgram GnRH pulses i.v. every 45 min for 48 h, i.e. during the period of negative feedback. The remaining 5 control gilts received comparable infusions of vehicle. Estradiol induced the characteristic biphasic LH response in control gilts. On the other hand, the inhibitory LH response to estradiol was prevented and the ensuing LH surge was blocked in 4 of the 5 gilts given GnRH pulses during the negative feedback phase. These results indicate that suppressing release of GnRH and/or LH is an important antecedent to full expression of the LH surge in ovariectomized pigs. Assimilation of this observation with the existing literature provides novel insights into the neuroendocrine control of LH secretion in castrated and ovary-intact gilts.

  2. Neurokinin-3 receptor activation in the retrochiasmatic area is essential for the full pre-ovulatory luteinising hormone surge in ewes.

    Science.gov (United States)

    Porter, K L; Hileman, S M; Hardy, S L; Nestor, C C; Lehman, M N; Goodman, R L

    2014-11-01

    Neurokinin B (NKB) is essential for human reproduction and has been shown to stimulate luteinising hormone (LH) secretion in several species, including sheep. Ewes express the neurokinin-3 receptor (NK3R) in the retrochiasmatic area (RCh) and there is one report that placement of senktide, an NK3R agonist, therein stimulates LH secretion that resembles an LH surge in ewes. In the present study, we first confirmed that local administration of senktide to the RCh produced a surge-like increase in LH secretion, and then tested the effects of this agonist in two other areas implicated in the control of LH secretion and where NK3R is found in high abundance: the preoptic area (POA) and arcuate nucleus (ARC). Bilateral microimplants containing senktide induced a dramatic surge-like increase in LH when given in the POA similar to that seen with RCh treatment. By contrast, senktide treatment in the ARC resulted in a much smaller but significant increase in LH concentrations suggestive of an effect on tonic secretion. The possible role of POA and RCh NK3R activation in the LH surge was next tested by treating ewes with SB222200, an NK3R antagonist, in each area during an oestradiol-induced LH surge. SB222200 in the RCh, but not in the POA, reduced the LH surge amplitude by approximately 40% compared to controls, indicating that NK3R activation in the former region is essential for full expression of the pre-ovulatory LH surge. Based on these data, we propose that the actions of NKB in the RCh are an important component of the pre-ovulatory LH surge in ewes. © 2014 British Society for Neuroendocrinology.

  3. Developmental Programming: Prenatal and Postnatal Androgen Antagonist and Insulin Sensitizer Interventions Prevent Advancement of Puberty and Improve LH Surge Dynamics in Prenatal Testosterone-Treated Sheep.

    Science.gov (United States)

    Padmanabhan, Vasantha; Veiga-Lopez, Almudena; Herkimer, Carol; Abi Salloum, Bachir; Moeller, Jacob; Beckett, Evan; Sreedharan, Rohit

    2015-07-01

    Prenatal T excess induces maternal hyperinsulinemia, early puberty, and reproductive/metabolic defects in the female similar to those seen in women with polycystic ovary syndrome. This study addressed the organizational/activational role of androgens and insulin in programming pubertal advancement and periovulatory LH surge defects. Treatment groups included the following: 1) control; 2) prenatal T; 3) prenatal T plus prenatal androgen antagonist, flutamide; 4) prenatal T plus prenatal insulin sensitizer, rosiglitazone; 5) prenatal T and postnatal flutamide; 6) prenatal T and postnatal rosiglitazone; and 7) prenatal T and postnatal metformin. Prenatal treatments spanned 30-90 days of gestation and postnatal treatments began at approximately 8 weeks of age and continued throughout. Blood samples were taken twice weekly, beginning at approximately 12 weeks of age to time puberty. Two-hour samples after the synchronization with prostaglandin F2α were taken for 120 hours to characterize LH surge dynamics at 7 and 19 months of age. Prenatal T females entered puberty earlier than controls, and all interventions prevented this advancement. Prenatal T reduced the percentage of animals having LH surge, and females that presented LH surge exhibited delayed timing and dampened amplitude of the LH surge. Prenatal androgen antagonist, but not other interventions, restored LH surges without normalizing the timing of the surge. Normalization of pubertal timing with prenatal/postnatal androgen antagonist and insulin sensitizer interventions suggests that pubertal advancement is programmed by androgenic actions of T involving insulin as a mediary. Restoration of LH surges by cotreatment with androgen antagonist supports androgenic programming at the organizational level.

  4. A Field Study of Lightning Surges Propagating through Low-voltage Electric Appliances

    Science.gov (United States)

    Ishii, Tsunayoshi; Sakamoto, Yoshiki; Oguchi, Shuichi; Okabe, Shigemitsu

    In today's highly information-based society, lightning damage has a significant impact on an increasing number of electric appliances such as personal computers and facsimile machines. Lightning surge protection devices for electric appliances are on the market and concern for lightning protection has been increasing, but there are still many unknown aspects of lightning surges that propagate into residences. To provide effective lightning protection measures, clarification of surge propagation patterns is needed. The Tokyo Electric Power Company has observed the patterns of lightning surge propagation into houses using lightning surge waveform detectors installed at ordinary residences and obtained data on 30 lightning surge current waveforms between 2008 and 2009. This paper discusses various aspects of lightning surge currents propagating into low-voltage appliances, including home electric appliances, based on the lightning surge current waveform data obtained from lightning observations. The result revealed the patterns of lightning surge currents propagating into the ground and lines of low-voltage appliances.

  5. Prediction of storm surge using tropical cyclone information based on a global atmosphere model and a tide-surge model

    Science.gov (United States)

    Yuk, Jin-Hee; Kim, Kyeong Ok; Park, Junghyun; Joh, Minsu

    2017-04-01

    The south-eastern coast of Korea (the Republic of Korea) has often been damaged by storm surge and high waves due to the typhoon, therefore it is important to predict typhoon movement and storm surge accurately and quickly. We made an attempt to 1-way couple the Model for Prediction Across Scales (MPAS), a global atmosphere model, and the ADvanced CIRCulation model (ADCIRC), a tide-surge model, i.e., providing the atmosphere model's outputs for tide-surge model's forcing. The MPAS has the unstructured Voronoi meshes and allows higher-resolution for the target area, thus the variable mesh system based on the mesh resolutions of 15 km in the region of interest, the western Pacific region and 60 km in the entire model domain was built and was run for prediction of typhoon once a day during summer, July to September. The ADCIRC model also has a flexible unstructured mesh, thus the high-resolution with minimum mesh size of 50 m was formed in the south-eastern coast. The typhoon information such as typhoon track, maximum wind, minimum air pressure and radius of storm can be extracted from the atmosphere model output using the Geophysical Fluid Dynamics Laboratory (GFDL) vortex tracker, and then the tide-surge model calculates the storm surge using Holland type vortex model and the typhoon information produced by the atmosphere model and vortex tracker. In this study, this coupled model system was used to predict the storm surge due to typhoon Chaba that occurred in the beginning of October, 2016 and struck the south-eastern coast of Korea. The estimated typhoon Chaba (201618) track's distance error was less than 100 km in 48 hours and 200 km in 72 hours, thus this global atmosphere model shows a good performance to predict the typhoon movement and is also comparable to forecasting agencies such as KMA, JMA and JTWC. Generally, the storm surge due to typhoon Chaba was reproduced reasonably for the south-eastern sea of Korea. The modelling system acquired in this study can

  6. Analysis of Acoustic Cavitation Surge in a Rocket Engine Turbopump

    Directory of Open Access Journals (Sweden)

    Hideaki Nanri

    2010-01-01

    Full Text Available In a liquid rocket engine, cavitation in an inducer of a turbopump sometimes causes instability phenomena when the inducer is operated at low inlet pressure. Cavitation surge (auto-oscillation, one such instability phenomenon, has been discussed mainly based on an inertia model assuming incompressible flow. When this model is used, the frequency of the cavitation surge decreases continuously as the inlet pressure of the turbopump decreases. However, we obtained an interesting experimental result in which the frequency of cavitation surge varied discontinuously. Therefore, we employed one-dimensional analysis based on an acoustic model in which the fluid is assumed to be compressible. The analytical result qualitatively corresponded with the experimental result.

  7. Electromagnetic computation methods for lightning surge protection studies

    CERN Document Server

    Baba, Yoshihiro

    2016-01-01

    This book is the first to consolidate current research and to examine the theories of electromagnetic computation methods in relation to lightning surge protection. The authors introduce and compare existing electromagnetic computation methods such as the method of moments (MOM), the partial element equivalent circuit (PEEC), the finite element method (FEM), the transmission-line modeling (TLM) method, and the finite-difference time-domain (FDTD) method. The application of FDTD method to lightning protection studies is a topic that has matured through many practical applications in the past decade, and the authors explain the derivation of Maxwell's equations required by the FDTD, and modeling of various electrical components needed in computing lightning electromagnetic fields and surges with the FDTD method. The book describes the application of FDTD method to current and emerging problems of lightning surge protection of continuously more complex installations, particularly in critical infrastructures of e...

  8. Storm surge modeling and applications in coastal areas

    Science.gov (United States)

    Dube, Shisir K.; Murty, Tad S.; Feyen, Jesse C.; Cabrera, Reggina; Harper, Bruce A.; Bales, Jerad D.; Amer, Saud A.

    2010-01-01

    This chapter introduces the reader to a wide spectrum of storm surge modeling systems used to assess the impact of tropical cyclones, covering a range of numerical methods, model domains, forcing and boundary conditions, and purposes. New technologies to obtain data such as deployment of temporary sensors and remote sensing practices to support modeling are also presented. Extensive storm surge modeling applications have been made with existing modeling systems and some of them are described in this chapter.The authors recognize the importance of evaluating river-ocean interactions in coastal environments during tropical cyclones. Therefore, the coupling of hydraulic (riverine) and storm surge models is discussed. In addition, results from studies performed in the coast of India are shown which generated maps to help emergency managers and reduce risk due to coastal inundation.

  9. Pediatric Disposition Classification (Reverse Triage) System to Create Surge Capacity.

    Science.gov (United States)

    Kelen, Gabor D; Sauer, Lauren; Clattenburg, Eben; Lewis-Newby, Mithya; Fackler, James

    2015-06-01

    Critically insufficient pediatric hospital capacity may develop during a disaster or surge event. Research is lacking on the creation of pediatric surge capacity. A system of "reverse triage," with early discharge of hospitalized patients, has been developed for adults and shows great potential but is unexplored in pediatrics. We conducted an evidence-based modified-Delphi consensus process with 25 expert panelists to derive a disposition classification system for pediatric inpatients on the basis of risk tolerance for a consequential medical event (CME). For potential validation, critical interventions (CIs) were derived and ranked by using a Likert scale to indicate CME risk should the CI be withdrawn or withheld for early disposition. Panelists unanimously agreed on a 5-category risk-based disposition classification system. The panelists established upper limit (mean) CME risk for each category as surge events.

  10. Modeling of surge characteristics in turbo heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hye Rim; Song, Seung Jin [Seoul National University, Seoul (Korea, Republic of); Kim, Kil Young [LS Mtron Co., Ltd., Anyang (Korea, Republic of)

    2009-07-01

    The study shows the theoretical analysis of surge dynamics in a turbo heat pump. The one-dimensional nonlinear model is developed. This is similar to the previous researches on unsteady analysis in simple compression system. But it is more complicated because the fluids in heat pumps undergo phase changes in heat exchangers and form closed-loop systems. So the two-phase flow effect and feedback effect from evaporator outlet to compressor inlet should be considered. The external conditions such as heat flux from cooling and chilled water are also important. Numerical results are presented to show the surge behavior in a turbo heat pump. It show that there are important parameters which determine the surge characteristics including Greitzer's B parameter and the other related to heat transfer in heat exchangers.

  11. Storm surges in the Western Black Sea. Operational forecasting

    Directory of Open Access Journals (Sweden)

    G. MUNGOV

    2000-06-01

    Full Text Available The frequency of the storm surges in the Black Sea is lower than that in other regions of the World Ocean but they cause significant damages as the magnitude of the sea level set-up is up to 7-8 times greater than that of other sea level variations. New methods and systems for storm surge forecasting and studying their statistical characteristics are absolutely necessary for the purposes of the coastal zone management. The operational forecasting storm surge model of Meteo-France was adopted for the Black Sea in accordance with the bilateral agreement between Meteo-France and NINMH. The model was verified using tide-gauge observations for the strongest storms observed along the Bulgarian coast over the last 10 years.

  12. Effect of naloxone and morphine on the estradiol induced LH surge in gilts

    OpenAIRE

    Yearwood, H.; Ziecik, A.J.; España España, F.

    1994-01-01

    This study examines the role of endogenous opioids in control of the estradiol-induced luteinizing hormone (LH) surge. In the experiment 1 (Exp.1), fifteen Duroc gills were ovarieclomized at the age of 5 to 6 months and one month later challenged with estradiol benzoate (EB, 25 µg/kg i.m.) at 0 h of the experiment. Control animals (n=5) received continuos i.v. infusion of saline solution (5 ml/h) from 30 to 34 h and from 60 to 64 h preceded by single i.v- injection of 10 ml of saline in each ...

  13. Excitation and voltage regulation for a 95 MVA surge-power generator

    CERN Document Server

    Bayer, K H

    1972-01-01

    The excitation equipment of the 95 MVA surge-power generator, which feeds the main ring magnets of the 28 GeV proton synchrotron at CERN in Geneva, is subject to certain abnormal requirements. They relate both to its dynamic control characteristics and to its accuracy of voltage regulation. These are essential in order to comply with the most stringent conditions made with respect to reproducibility of magnet cycles over the whole duration of an experimenting period of three to four weeks. A special control concept also ensures optimum results in this respect for the dynamic transition regions within a pulse cycle. (4 refs).

  14. Development of the Second-Generation Oscillating Surge Wave Energy Converter with Variable Geometry

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Thresher, Robert W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Abbas, Nikhar [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kelly, Michael [South Dakota School of Mines and Technology

    2017-06-03

    This study investigates the effect of design changes on the hydrodynamics of a novel oscillating surge wave energy converter being developed at the National Renewable Energy Laboratory. The design utilizes controllable geometry features to shed structural loads while maintaining a rated power over a greater number of sea states. The second-generation design will seek to provide a more refined control of performance because the first-generation design demonstrated performance reductions considered too large for smooth power output. Performance is evaluated using frequency domain analysis with consideration of a nonideal power-take-off system, with respect to power absorption, foundation loads, and power-take-off torque.

  15. Development of the Second-Generation Oscillating Surge Wave Energy Converter with Variable Geometry: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Thresher, Robert W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kelly, Michael [South Dakota School of Mines

    2017-07-25

    This study investigates the effect of design changes on the hydrodynamics of a novel oscillating surge wave energy converter being developed at the National Renewable Energy Laboratory. The design utilizes controllable geometry features to shed structural loads while maintaining a rated power over a greater number of sea states. The second-generation design will seek to provide a more refined control of performance because the first-generation design demonstrated performance reductions considered too large for smooth power output. Performance is evaluated using frequency domain analysis with consideration of a nonideal power-take-off system, with respect to power absorption, foundation loads, and power-take-off torque.

  16. On the Response of Interleaved Transformer Windings to Surge Voltages

    DEFF Research Database (Denmark)

    Pedersen, A.

    1963-01-01

    The high series capacitance theory for the response of interleaved transformer windings to surge voltages is criticized from the point of view that an increased series capacitance as a result of interleaving is incompatible with the concept of a pure capacitive initial voltage distribution. A new...... theory is proposed according to which the distributed earth capacitances are charged up during an initial period by heavy currents flowing into the winding through surge impedances formed by the coils as a result of interleaving. Formulas are derived for the initial voltage distribution...

  17. Probabilistic Storm Surge Hazard Assessment in the French West Indies

    Science.gov (United States)

    Krien, Y.; Dudon, B.; Roger, J.; Zahibo, N.; Arnaud, G.

    2016-12-01

    The French West Indies are prone to hurricanes formed over the warm tropical waters of the Atlantic Ocean and Caribbean Sea. These events can have great consequences in terms of human, property, and economic losses. Storm surge hazard assessment is therefore required to provide guidance to emergency managers and decision-makers. By combining statistical-deterministic approaches and wave-current coupled models, we assessed storm surge hazard in Guadeloupe and Martinique islands. We present here the methodology, the results, as well as the on-going work on the impact of climate change in the framework of the FEDER-funded project C3AF.

  18. Ovarian modulation of the oestradiol-induced LH surge in prepubertal and sexually mature gilts.

    Science.gov (United States)

    Elsaesser, F; Parvizi, N; Foxcroft, G

    1998-05-01

    The role of ovarian secretions in modulating positive oestrogen feedback on LH release in late prepubertal and sexually mature gilts was studied. Gilts were either ovariectomized (OVX) at 230 days of age (sexually mature, OVX 230, control), ovariectomized at 160 days of age (pre-pubertal, OVX 160) or ovariectomized at 160 days of age and given either low, high or very high oestradiol substitution therapy (two or three Silastic implants, 5 or 8 cm in length) from 160 days to 230 days (OVX 160 + 2E5, OVX 160 + 2E8 and OVX 160 + 3E8, respectively). The LH surge responses to three i.m. injections of oestradiol benzoate given at intervals of 12 h (in total 10 micrograms oestradiol benzoate kg-1 bodyweight) were compared at 260 days. An additional group of sexually mature gilts was ovariectomized at 260 days (OVX 260) and challenged with oestradiol benzoate at 360 days. LH surges with peak LH concentrations below pretreatment values (resembling LH responses to oestradiol benzoate in immature gilts) were classified as immature, and those with peak LH concentrations above pretreatment values as mature. LH concentrations before treatment with oestradiol benzoate were reduced (P gilts compared with OVX 230 (control). When compared with the control group, the time to LH surge peak was longer in OVX 260 gilts, LH peak amplitude was reduced in the OVX 160 group and the area under the curve of the LH surge (ng LH ml-1 plasma (48 h)-1) was less in all other groups (P gilts (6/1) and a low ratio in OVX 160 (1/7) and OVX 260 (1/6) gilts. The long-term effect of ovariectomy was partially overcome in the OVX 160 + 2E5 group (mature:immature = 3/3). However, previous exposure to supraphysiological concentrations of oestradiol (as in groups OVX 160 + 2E8 and OVX 160 + 3E8) resulted in a high percentage of animals (66% and 100%, respectively) that did not respond to the oestradiol benzoate challenge with an LH surge. Immediately before oestradiol benzoate administration (30 days after

  19. Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M.; Yu, Yi-Hsiang; Wright, Alan D.; Lawson, Michael

    2016-06-24

    The aim of this paper is to describe how to control the power-to-load ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the time-averaged power, but to also consider the power-take-off (PTO) torque and foundation forces that arise because of WEC motion. The objective function of the controller will include competing terms that force the controller to balance power capture with structural loading. Separate penalty weights were placed on the surge-foundation force and PTO torque magnitude, which allows the controller to be tuned to emphasize either power absorption or load shedding. Results of this study found that, with proper selection of penalty weights, gains in time-averaged power would exceed the gains in structural loading while minimizing the reactive power requirement.

  20. Study of a Novel Oscillating Surge Wave Energy Converter: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Choiniere, Michael [University of Maine; Thiagarajan, Krish P. [University of Maine

    2017-08-01

    This study investigates the performance of an oscillating surge wave energy converter (OSWEC) that utilizes adjustable geometry as a means of controlling the hydrodynamic coefficients, a concept originally proposed by [1]. The body of the device consists of a bottom-hinged solid rectangular frame with five horizontal flaps spanning the interior of the frame. The flaps can rotate independently about their center of rotation within the frame like a large window shutter. Changing the orientation of the flaps alters the hydrodynamic coefficients and natural frequency of the device as well as the ability to shed or absorb structural loads accordingly. This ability may allow the device to operate in a wider range of sea states than other current wave energy converter designs. This paper presents and compares the results of numerical simulations and experimental testing of the OSWEC's response to regular waves with all five of the horizontal fin configurations sharing the same orientation of 0 degrees (fully closed interior) and 90 degrees (fully open). The numerical simulations were performed using WAMIT, which calculates hydrodynamic coefficients using a boundary element method code to solve the linear potential flow problem, and WEC-Sim, a MATLAB-based tool that simulates multibody devices in the time domain by solving the governing equations of motion. A 1:14 scale model of the device was built for experimental evaluation in an 8-m-long, 1-m wide wave tank, which supports a water depth of 0.7 m. The OSWEC motion in different wave conditions was measured with displacement sensors while nonlinear wave-structure interaction effects like slamming and overtopping were captured using a high-speed camera and used to understand differences between the simulation and experiments.

  1. ISSN 2073-9990 East Cent. Afr. J. surg. (Online)

    African Journals Online (AJOL)

    dell

    Afr. J. surg. (Online). COSECSA/ASEA Publication -East and Central African Journal of Surgery April 2013; Vol. 18 N0.1. Barium enema with reference to rectal biopsy for the diagnosis and exclusion of. Hirschsprung disease. W. Esayias1, Y. Hawaz1, B. Dejene2, W. Ergete3. Department of Radiology, School of Medicine, ...

  2. ISSN 2073-9990 East Cent. Afr. J. surg

    African Journals Online (AJOL)

    Hp 630 Dual Core

    Afr. J. surg. COSECSA/ASEA Publication - East and Central African Journal of Surgery. 2016 ; Volume 21 Number 1. Aetiology and Treatment Outcome of Severe Traumatic Brain Injuries in. Neurosurgical Center with Inadequate Facilities. M O N. Nnadi1, O B Bankole2, J O Olatosi3, T A Edentekhe4., B G Fente5. 1Division ...

  3. Model simulation of storm surge potential for Andaman islands

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, V.S.; RameshBabu, V.; Babu, M.T.; Dhinakaran, G.; Rajamanickam, G.V.

    The Andaman Islands face the surge disaster threat as their north-south orientation comes across the eastward path of severe cyclones moving from the Andaman sea known for the genesis of many severe cyclones that traverse the Bay of Bengal regularly...

  4. ISSN 2073-9990 East Cent. Afr. J. surg

    African Journals Online (AJOL)

    Hp 630 Dual Core

    PediatrSurgInt 2006; 22: 446 8. 8. Feins NR, Dzakovic A, Papadakis K. Minimally invasive closure of pediatric umbilical hernias. 2008; 43: 127 30. 9. Massamba Miabaou D, Passi Lc, Elé N, et al. Problèmes de prise en charge des urgences chirurgicales abdominales au cHU de Brazzaville. J Afrchir Digest 2013 ; 13: 1510 4.

  5. Into the Surge of Network-driven Innovation

    DEFF Research Database (Denmark)

    Østergaard, Claus Møller; Rosenstand, Claus Andreas Foss; Gertsen, Frank

    2013-01-01

    The ambition of this paper is to provide a better theoretical understanding of innovation by framing it in a long historical, economical, and societal perspective. The research question of the paper is: What characterize the historical surges of innovation? Based on previous works and research...

  6. A novel parameter estimation method for metal oxide surge arrester ...

    Indian Academy of Sciences (India)

    In this paper, a new technique, which is the combination of Adaptive Particle Swarm Optimization (APSO) and Ant Colony Optimization (ACO) algorithms and linking the MATLAB and EMTP, is proposed to estimate the parameters of MO surge arrester models. The proposed algorithm is named Modified Adaptive Particle ...

  7. ISSN 2073-9990 East Cent. Afr. J. surg

    African Journals Online (AJOL)

    Hp 630 Dual Core

    ISSN 2073-9990 East Cent. Afr. J. surg. COSECSA/ASEA Publication -East & Central African Journal of Surgery. March/April 2016 Volume 21 (1) cerebrospinal fluid or blood, 6 mL 2% lidocaine with 1:200,000 epinephrine was injected, followed by the insertion of 18G catheter (Perifix, B. Braun, Melsungen,. Germany) 3.0 ...

  8. ISSN 2073-9990 East Cent. Afr. J. surg

    African Journals Online (AJOL)

    Hp 630 Dual Core

    Afr. J. surg. COSECSA/ASEA Publication - East and Central African Journal of Surgery. December 2016; Vol. 21 No. 3. The Surgical Management of Primary Hyperparathyroidism: The Experience in Tikur nbessa. Specialized Tertiary Referral and Teaching Hospital, ddis baba, Ethiopia. Sahilu Wondimu1, Berhanu Nega2.

  9. 14 CFR 33.65 - Surge and stall characteristics.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Surge and stall characteristics. 33.65 Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... stall characteristics. When the engine is operated in accordance with operating instructions required by...

  10. A Surge of Interest in Uganda's Art Deco | Craddock Williams ...

    African Journals Online (AJOL)

    A Surge of Interest in Uganda's Art Deco. Vivian Craddock Williams. Abstract. No Abstract. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/uj.v46i1.23038 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...

  11. Why does substorm-associated auroral surge travel westward?

    Science.gov (United States)

    Ebihara, Y.; Tanaka, T.

    2018-01-01

    A substorm is a long-standing unsolved issue in solar-terrestrial physics. One of the big challenges is to explain reasonably the evolution of the morphological structure of the aurora associated with the substorm. The sudden appearance of a bright aurora and an auroral surge traveling westward (westward traveling surge, WTS) are noticeable features of the aurora during the substorm expansion phase. By using a global magnetohydrodynamics (MHD) simulation, we obtained the following results regarding the WTS. When the interplanetary magnetic field turns southward, a persistent dynamo appears in the cusp/mantle region, driving the two-cell magnetospheric convection. Then, the substorm growth phase begins. When magnetic reconnection takes place in the magnetotail, plasma is accelerated earthward in the plasma sheet, and accelerated toward the equatorial plane in the lobe. The second dynamo appears in the near-Earth region, which is closely associated with the generation of the field-aligned current (FAC) on the nightside. When the FAC reaches the ionosphere, the aurora becomes bright, and the onset of the expansion phase begins. In the ionosphere, the conductivity is intensified in the bright aurora due to the precipitation of accelerated electrons. The conductivity gradient gives rise to the overflow of the Hall current, which acts as the third dynamo. The overflow results in the accumulation of space charge, which causes a divergent electric field. The divergent electric field generates a thin, structured upward FAC adjacent to the bright aurora. The opposite process takes place on the opposite side of the bright aurora. In short, the upward FAC increases (appearance of aurora) at the leading edge of the surge, and decreases (disappearance of aurora) at the trailing edge of the surge. By repeating these processes, the surge seems to travel westward.

  12. Assessment of water pipes durability under pressure surge

    Science.gov (United States)

    Pham Ha, Hai; Minh, Lanh Pham Thi; Tang Van, Lam; Bulgakov, Boris; Bazhenova, Soafia

    2017-10-01

    Surge phenomenon occurs on the pipeline by the closing valve or pump suddenly lost power. Due to the complexity of the water hammer simulation, previous researches have only considered water hammer on the single pipe or calculation of some positions on water pipe network, it have not been analysis for all of pipe on the water distribution systems. Simulation of water hammer due to closing valve on water distribution system and the influence level of pressure surge is evaluated at the defects on pipe. Water hammer on water supply pipe network are simulated by Water HAMMER software academic version and the capacity of defects are calculated by SINTAP. SINTAP developed from Brite-Euram projects in Brussels-Belgium with the aim to develop a process for assessing the integrity of the structure for the European industry. Based on the principle of mechanical fault, indicating the size of defects in materials affect the load capacity of the product in the course of work, the process has proposed setting up the diagram to fatigue assessment defect (FAD). The methods are applied for water pipe networks of Lien Chieu district, Da Nang city, Viet Nam, the results show the affected area of wave pressure by closing the valve and thereby assess the greatest pressure surge effect to corroded pipe. The SINTAP standard and finite element mesh analysis at the defect during the occurrence of pressure surge which will accurately assess the bearing capacity of the old pipes. This is one of the bases to predict the leakage locations on the water distribution systems. Amount of water hammer when identified on the water supply networks are decreasing due to local losses at the nodes as well as the friction with pipe wall, so this paper adequately simulate water hammer phenomena applying for actual water distribution systems. The research verified that pipe wall with defect is damaged under the pressure surge value.

  13. Evidence of surges overtopping a large topographic barrier: Salina island, Aeolian Archipelago, Italy

    Science.gov (United States)

    Lanzafame, G.; Lucchi, F. Ricci; Rossi, P. L.

    1987-07-01

    Surge-type deposits mantling a volcanic cone (Fossa Felci) derive from an adjacent eruptive center, not from the volcano itself. Erosional and depositional evidence of the surge mechanism is presented. The topographic obstacle supposed to be overtopped by the surges was over 600 m high.

  14. 30 CFR 57.16002 - Bins, hoppers, silos, tanks, and surge piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... NONMETAL MINES Materials Storage and Handling § 57.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled...

  15. 30 CFR 56.16002 - Bins, hoppers, silos, tanks, and surge piles.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... MINES Materials Storage and Handling § 56.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled or...

  16. Surge capacity logistics: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement.

    Science.gov (United States)

    Einav, Sharon; Hick, John L; Hanfling, Dan; Erstad, Brian L; Toner, Eric S; Branson, Richard D; Kanter, Robert K; Kissoon, Niranjan; Dichter, Jeffrey R; Devereaux, Asha V; Christian, Michael D

    2014-10-01

    Successful management of a pandemic or disaster requires implementation of preexisting plans to minimize loss of life and maintain control. Managing the expected surges in intensive care capacity requires strategic planning from a systems perspective and includes focused intensive care abilities and requirements as well as all individuals and organizations involved in hospital and regional planning. The suggestions in this article are important for all involved in a large-scale disaster or pandemic, including front-line clinicians, hospital administrators, and public health or government officials. Specifically, this article focuses on surge logistics-those elements that provide the capability to deliver mass critical care. The Surge Capacity topic panel developed 23 key questions focused on the following domains: systems issues; equipment, supplies, and pharmaceuticals; staffing; and informatics. Literature searches were conducted to identify studies upon which evidence-based recommendations could be made. The results were reviewed for relevance to the topic, and the articles were screened by two topic editors for placement within one of the surge domains noted previously. Most reports were small scale, were observational, or used flawed modeling; hence, the level of evidence on which to base recommendations was poor and did not permit the development of evidence-based recommendations. The Surge Capacity topic panel subsequently followed the American College of Chest Physicians (CHEST) Guidelines Oversight Committee's methodology to develop suggestion based on expert opinion using a modified Delphi process. This article presents 22 suggestions pertaining to surge capacity mass critical care, including requirements for equipment, supplies, and pharmaceuticals; staff preparation and organization; methods of mitigating overwhelming patient loads; the role of deployable critical care services; and the use of transportation assets to support the surge response

  17. Ablation of KNDy Neurons Results in Hypogonadotropic Hypogonadism and Amplifies the Steroid-Induced LH Surge in Female Rats.

    Science.gov (United States)

    Mittelman-Smith, Melinda A; Krajewski-Hall, Sally J; McMullen, Nathaniel T; Rance, Naomi E

    2016-05-01

    In the human infundibular (arcuate) nucleus, a subpopulation of neurons coexpress kisspeptin and neurokinin B (NKB), 2 peptides required for normal reproductive function. A homologous group of neurons exists in the arcuate nucleus of rodents, termed KNDy neurons based on the coexpression of kisspeptin, NKB, and dynorphin. To study their function, we recently developed a method to selectively ablate KNDy neurons using NK3-SAP, a neurokinin 3 receptor agonist conjugated to saporin (SAP). Here, we ablated KNDy neurons in female rats to determine whether these neurons are required for estrous cyclicity and the steroid induced LH surge. NK3-SAP or Blank-SAP (control) was microinjected into the arcuate nucleus using stereotaxic surgery. After monitoring vaginal smears for 3-4 weeks, rats were ovariectomized and given 17β-estradiol and progesterone in a regimen that induced an afternoon LH surge. Rats were killed at the time of peak LH levels, and brains were harvested for NKB and dual labeled GnRH/Fos immunohistochemistry. In ovary-intact rats, ablation of KNDy neurons resulted in hypogonadotropic hypogonadism, characterized by low levels of serum LH, constant diestrus, ovarian atrophy with increased follicular atresia, and uterine atrophy. Surprisingly, the 17β-estradiol and progesterone-induced LH surge was 3 times higher in KNDy-ablated rats. Despite the marked increase in the magnitude of the LH surge, the number of GnRH or anterior ventral periventricular nucleus neurons expressing Fos was not significantly different between groups. Our studies show that KNDy neurons are essential for tonic levels of serum LH and estrous cyclicity and may play a role in limiting the magnitude of the LH surge.

  18. Release of Norepinephrine in the Preoptic Area Activates Anteroventral Periventricular Nucleus Neurons and Stimulates the Surge of Luteinizing Hormone

    Science.gov (United States)

    Poletini, Maristela O.; Leite, Cristiane M.; Bernuci, Marcelo P.; Kalil, Bruna; Mendonça, Leonardo B.D.; Carolino, Ruither O. G.; Helena, Cleyde V. V.; Bertram, Richard; Franci, Celso R.; Anselmo-Franci, Janete A.

    2013-01-01

    The role of norepinephrine (NE) in regulation of LH is still controversial. We investigated the role played by NE in the positive feedback of estradiol and progesterone. Ovarian-steroid control over NE release in the preoptic area (POA) was determined using microdialysis. Compared with ovariectomized (OVX) rats, estradiol-treated OVX (OVX+E) rats displayed lower release of NE in the morning but increased release coincident with the afternoon surge of LH. OVX rats treated with estradiol and progesterone (OVX+EP) exhibited markedly greater NE release than OVX+E rats, and amplification of the LH surge. The effect of NE on LH secretion was confirmed using reverse microdialysis. The LH surge and c-Fos expression in anteroventral periventricular nucleus neurons were significantly increased in OVX+E rats dialyzed with 100 nm NE in the POA. After Fluoro-Gold injection in the POA, c-Fos expression in Fluoro-Gold/tyrosine hydroxylase-immunoreactive neurons increased during the afternoon in the A2 of both OVX+E and OVX+EP rats, in the locus coeruleus (LC) of OVX+EP rats, but was unchanged in the A1. The selective lesion of LC terminals, by intracerebroventricular N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine, reduced the surge of LH in OVX+EP but not in OVX+E rats. Thus, estradiol and progesterone activate A2 and LC neurons, respectively, and this is associated with the increased release of NE in the POA and the magnitude of the LH surge. NE stimulates LH secretion, at least in part, through activation of anteroventral periventricular neurons. These findings contribute to elucidation of the role played by NE during the positive feedback of ovarian steroids. PMID:23150494

  19. Implementing a negative-pressure isolation ward for a surge in airborne infectious patients.

    Science.gov (United States)

    Miller, Shelly L; Clements, Nicholas; Elliott, Steven A; Subhash, Shobha S; Eagan, Aaron; Radonovich, Lewis J

    2017-06-01

    During a large-scale airborne infectious disease outbreak, the number of patients needing hospital-based health care services may exceed available negative-pressure isolation room capacity. To test one method of increasing hospital surge capacity, a temporary negative-pressure isolation ward was established at a fully functioning hospital. Negative pressure was achieved in a 30-bed hospital ward by adjusting the ventilation system. Differential pressure was continuously measured at 22 locations, and ventilation airflow was characterized throughout the ward. The pressure on the test ward relative to the main hospital hallway was -29 Pa on average, approximately 10 times higher than the Centers for Disease Control and Prevention guidance for airborne infection control. No occurrences of pressure reversal occurred at the entrances to the ward, even when staff entered the ward. Pressures within the ward changed, with some rooms becoming neutrally or slightly positively pressurized. This study showed that establishing a temporary negative-pressure isolation ward is an effective method to increase surge capacity in a hospital. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. All rights reserved.

  20. Numerical Experiments for Storm Surge Inundation in Korean Coastal Area

    Science.gov (United States)

    Yoon, J.; Shim, J.; Jun, K.

    2012-12-01

    Sea-level rising due to climate change following the global warming and the increased intensity of typhoon are magnifying inundation hazards up to the unpredictable level, resulting from the typhoon surge in Korea and other coastal states around the world. Typhoon is the most serious natural disaster in Korean coastal area. Many people died by storm surge inundation every year. And typhoon caused a lot of damage to property. Climate changes due to global warming are producing a stronger natural disaster. Coastal zones have been damaged by typhoons and accompanying storm surge. Especially, the most serious loss of life and terrible property damage caused by typhoon Maemi in 2003. The typhoon Maemi invaded Korean Peninsula leaving property loss of $ 4 Billion and killing 131 people. After then, there has been an increased interest in these coastal zone problems. If storm surges coincide with high tides, the loss of life and property damage due to high waters arc even worse. Therefore it is desirable to accurately forecast the amount water level increase. In this study, using a numerical model FVCOM(finite volume coastal circulation model, Chen et al.,2004), storm surge was simulated to examine its fluctuation characteristics for the coastal area behind Masan, Yeosu and Busan city in Korea. In the numerical model, a moving boundary condition(wet-dry treatment) was incorporated to explain wave inundation. To simulate the inundation scenario, the model grids were extended up to the area inside the lowland in application of the digital elevation data(DEM) made by precisely combining the aero-LiDAR survey data and bathymetry data for the 3 demonstration regions of Busan, Masan and Yeosu. Minimum grid of 300 m unstructured triangular mesh applied to calculate the storm surge was adopted as a grid system. And the minimum grid size of 30 m was built near Busan, Masan and Yeosu area which are the fine coastal regions and where the inundation is simulated. Numerically

  1. Use of historical information in extreme storm surges frequency analysis

    Science.gov (United States)

    Hamdi, Yasser; Duluc, Claire-Marie; Deville, Yves; Bardet, Lise; Rebour, Vincent

    2013-04-01

    The prevention of storm surge flood risks is critical for protection and design of coastal facilities to very low probabilities of failure. The effective protection requires the use of a statistical analysis approach having a solid theoretical motivation. Relating extreme storm surges to their frequency of occurrence using probability distributions has been a common issue since 1950s. The engineer needs to determine the storm surge of a given return period, i.e., the storm surge quantile or design storm surge. Traditional methods for determining such a quantile have been generally based on data from the systematic record alone. However, the statistical extrapolation, to estimate storm surges corresponding to high return periods, is seriously contaminated by sampling and model uncertainty if data are available for a relatively limited period. This has motivated the development of approaches to enlarge the sample extreme values beyond the systematic period. The nonsystematic data occurred before the systematic period is called historical information. During the last three decades, the value of using historical information as a nonsystematic data in frequency analysis has been recognized by several authors. The basic hypothesis in statistical modeling of historical information is that a perception threshold exists and that during a giving historical period preceding the period of tide gauging, all exceedances of this threshold have been recorded. Historical information prior to the systematic records may arise from high-sea water marks left by extreme surges on the coastal areas. It can also be retrieved from archives, old books, earliest newspapers, damage reports, unpublished written records and interviews with local residents. A plotting position formula, to compute empirical probabilities based on systematic and historical data, is used in this communication paper. The objective of the present work is to examine the potential gain in estimation accuracy with the

  2. Rapid Response Measurements of Hurricane Waves and Storm Surge

    Science.gov (United States)

    Gravois, U.

    2010-12-01

    Andrew (1992), Katrina (2005), and Ike (2008) are recent examples of extensive damage that resulted from direct hurricane landfall. Some of the worst damages from these hurricanes are caused by wind driven waves and storm surge flooding. The potential for more hurricane disasters like these continues to increase as a result of population growth and real estate development in low elevation coastal regions. Observational measurements of hurricane waves and storm surge play an important role in future mitigation efforts, yet permanent wave buoy moorings and tide stations are more sparse than desired. This research has developed a rapid response method using helicopters to install temporary wave and surge gauges ahead of hurricane landfall. These temporary installations, with target depths from 10-15 m and 1-7 km offshore depending on the local shelf slope, increase the density of measurement points where the worst conditions are expected. The method has progressed to an operational state and has successfully responded to storms Ernesto (2006), Noel (2007), Fay (2008), Gustav (2008), Hanna (2008) and Ike (2008). The temporary gauges are pressure data loggers that measure at 1 Hz continuously for 12 days and are post-processed to extract surge and wave information. For the six storms studied, 45 out of 49 sensors were recovered by boat led scuba diver search teams, with 43 providing useful data for an 88 percent success rate. As part of the 20 sensor Hurricane Gustav response, sensors were also deployed in lakes and bays inLouisiana, east of the Mississippi river delta. Gustav was the largest deployment to date. Generally efforts were scaled back for storms that were not anticipated to be highly destructive. For example, the cumulative total of sensors deployed for Ernesto, Noel, Fay and Hanna was only 20. Measurement locations for Gustav spanned over 800 km of exposed coastline from Louisiana to Florida with sensors in close proximity to landfall near Cocodrie

  3. Using Adaptive Mesh Refinment to Simulate Storm Surge

    Science.gov (United States)

    Mandli, K. T.; Dawson, C.

    2012-12-01

    Coastal hazards related to strong storms such as hurricanes and typhoons are one of the most frequently recurring and wide spread hazards to coastal communities. Storm surges are among the most devastating effects of these storms, and their prediction and mitigation through numerical simulations is of great interest to coastal communities that need to plan for the subsequent rise in sea level during these storms. Unfortunately these simulations require a large amount of resolution in regions of interest to capture relevant effects resulting in a computational cost that may be intractable. This problem is exacerbated in situations where a large number of similar runs is needed such as in design of infrastructure or forecasting with ensembles of probable storms. One solution to address the problem of computational cost is to employ adaptive mesh refinement (AMR) algorithms. AMR functions by decomposing the computational domain into regions which may vary in resolution as time proceeds. Decomposing the domain as the flow evolves makes this class of methods effective at ensuring that computational effort is spent only where it is needed. AMR also allows for placement of computational resolution independent of user interaction and expectation of the dynamics of the flow as well as particular regions of interest such as harbors. The simulation of many different applications have only been made possible by using AMR-type algorithms, which have allowed otherwise impractical simulations to be performed for much less computational expense. Our work involves studying how storm surge simulations can be improved with AMR algorithms. We have implemented relevant storm surge physics in the GeoClaw package and tested how Hurricane Ike's surge into Galveston Bay and up the Houston Ship Channel compares to available tide gauge data. We will also discuss issues dealing with refinement criteria, optimal resolution and refinement ratios, and inundation.

  4. Pressurizer with a mechanically attached surge nozzle thermal sleeve

    Science.gov (United States)

    Wepfer, Robert M

    2014-03-25

    A thermal sleeve is mechanically attached to the bore of a surge nozzle of a pressurizer for the primary circuit of a pressurized water reactor steam generating system. The thermal sleeve is attached with a series of keys and slots which maintain the thermal sleeve centered in the nozzle while permitting thermal growth and restricting flow between the sleeve and the interior wall of the nozzle.

  5. Surge ammonium uptake in macroalgae from a coral atoll

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, V.; Wafar, M.V.M.

    surge uptake of ammonium is not frequently measured, it could be an important mechanism of N acquisition for macroalgae in nutrient-poor reef waters given the diversity of heterotrophs habiting on them and in the vicinity. Seaweed surfaces... provide all of or more than the quantity of N required by the alga, removal by dilution (Taylor and Rees, 1998) could substantially reduce the amount of N that actually becomes available to the alga from the heterotrophs. Efficient acquisition of N from...

  6. Hospitals Capability in Response to Disasters Considering Surge Capacity Approach

    Directory of Open Access Journals (Sweden)

    Gholamreza Khademipour

    2016-01-01

    Full Text Available Background: The man-made and natural disasters have adverse effects with sound, apparent, and unknown consequences. Among various components of disaster management in health sector, the most important role is performed by health-treatment systems, especially hospitals. Therefore, the present study aimed to evaluate the surge capacity of hospitals of Kerman Province in disaster in 2015. Materials and Methods: This is a quantitative study, conducted on private, military, and medical sciences hospitals of Kerman Province. The sampling method was total count and data collection for the research was done by questionnaire. The first section of the questionnaire included demographic information of the studied hospitals and second part examined the hospital capacity in response to disasters in 4 fields of equipment, physical space, human resources, and applied programs. The extracted data were analyzed by descriptive statistics. Results: The mean capability of implementing the surge capacity programs by hospitals of Kerman Province in disasters and in 4 fields of equipment, physical space, human resources, and applied programs was evaluated as 7.33% (weak. The surge capacity capability of state hospitals in disasters was computed as 8% and compared to private hospitals (6.07% had a more suitable condition. Conclusion: Based on the results of study and significance of preparedness of hospitals in response to disasters, it is proposed that managers of studied hospitals take measures to promote the hospital response capacity to disasters based on 4 components of increasing hospital capacity.

  7. PD detection caused by surge voltages in stator winding

    Energy Technology Data Exchange (ETDEWEB)

    Hiroshima, S.; Hirose, T.; Maeda, T. [Toshiba Corp., Mie (Japan); Tsuda, T.; Wakimoto, Y.; Yoshimitsu, T. [Toshiba Mitsubishi-Electric Industrial Systems Corp., Yokohama (Japan)

    2009-07-01

    Surge voltages can cause partial discharges (PDs) within coils, leading to the degradation of electrical insulation materials. This study investigated the influence of propagation on PD signals in a stator coil under surge voltages. The aim of the study was to test the ability of a PD alert system to detect PD signals propagating through a motor. The stator winding of a 3-phase random wound motor was used in the experimental set-up. A unipolar impulse voltage was applied to the U-phase coils. The applied impulse voltage contained a high frequency component to test non-uniform impressions of the voltage in each coil. A twisted pairs cable was connected to the motor winding in parallel in order to simulate the PD that occurred between turns inside the motor. A surge voltage was applied to the motor terminal. Results of the study showed that PD signals propagating through the motor can be detected by the PDA system. The signals were detected when PDs were generated in the first and second coils. PDs were also measured in a coil that simulated a winding flaw by providing a contact point between the coil jumper wires. 3 refs., 2 tabs., 12 figs.

  8. Developing a Mass Casualty Surge Capacity Protocol for Emergency Medical Services to Use for Patient Distribution.

    Science.gov (United States)

    Shartar, Samuel E; Moore, Brooks L; Wood, Lori M

    2017-12-01

    Metropolitan areas must be prepared to manage large numbers of casualties related to a major incident. Most US cities do not have adequate trauma center capacity to manage large-scale mass casualty incidents (MCIs). Creating surge capacity requires the distribution of casualties to hospitals that are not designated as trauma centers. Our objectives were to extrapolate MCI response research into operational objectives for MCI distribution plan development; formulate a patient distribution model based on research, hospital capacities, and resource availability; and design and disseminate a casualty distribution tool for use by emergency medical services (EMS) personnel to distribute patients to the appropriate level of care. Working with hospitals within the region, we refined emergency department surge capacity for MCIs and developed a prepopulated tool for EMS providers to use to distribute higher-acuity casualties to trauma centers and lower-acuity casualties to nontrauma hospitals. A mechanism to remove a hospital from the list of available resources, if it is overwhelmed with patients who self-transport to the location, also was put into place. The number of critically injured survivors from an MCI has proven to be consistent, averaging 7% to 10%. Moving critically injured patients to level 1 trauma centers can result in a 25% reduction in mortality, when compared with care at nontrauma hospitals. US cities face major gaps in the surge capacity needed to manage an MCI. Sixty percent of "walking wounded" casualties self-transport to the closest hospital(s) to the incident. Directing critically ill patients to designated trauma centers has the potential to reduce mortality associated with the event. When applied to MCI responses, damage-control principles reduce resource utilization and optimize surge capacity. A universal system for mass casualty triage was identified and incorporated into the region's EMS. Flagship regional coordinating hospitals were designated

  9. Evidence that nitric oxide may mediate the ovarian steroid-induced luteinizing hormone surge: involvement of excitatory amino acids.

    Science.gov (United States)

    Bonavera, J J; Sahu, A; Kalra, P S; Kalra, S P

    1993-12-01

    The involvement of excitatory N-methyl-D-aspartate (NMDA) receptors in the hypothalamic control of pituitary LH secretion is well recognized. Recent evidence shows that nitric oxide (NO), a free radical gas, may act as neurotransmitter in the brain, and its efflux is stimulated by activation of NMDA receptors. Studies were undertaken to determine whether NO is involved in the hypothalamic release of LHRH and in the LH surge induced by progesterone (P) in estrogen-primed ovariectomized rats. Rats were ovariectomized and 2 weeks later received estradiol benzoate (30 micrograms sc) at 1000 h. Two days later, P was injected at 1000 h to potentiate the estradiol benzoate-induced LH surge in the afternoon. Serial blood samples were collected at hourly intervals from 1400-1800 h via an intraatrial cannula implanted the day before P injection. Additionally, at various times before onset of the LH surge at 1400 h, the rats were injected sc with one of three inhibitors of NO synthase, the enzyme that generates NO. Control, saline-injected rats showed unambiguous LH surges in the afternoon. However, either a single injection at 1000 h of NG-methyl-L-arginine (20 mg/kg) or three injections at 1000, 1200, and 1400 h of either Nw-nitro-L-arginine methyl ester (NAME, 40 mg/kg) or Nw-nitro-L-arginine (60 mg/kg) to inhibit NO efflux markedly suppressed the P-induced LH surge in the afternoon. To ascertain whether suppression of LH surge was due to blockade of hypothalamic LHRH release, a series of in vitro studies were performed in steroid-primed rats. First we examined the effects of sodium nitroprusside (NPS), a compound that spontaneously generates and releases NO. NPS increased basal and KCl-induced LHRH release in vitro from the medial basal hypothalamus-preoptic area and median eminence fragments. No direct effect of NO at the pituitary level was seen, since NPS did not alter basal or LHRH-induced LH in vitro release from hemipituitaries. In addition, we tested the effects of

  10. Reliability Effects of Surge Current Testing of Solid Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2007-01-01

    Solid tantalum capacitors are widely used in space applications to filter low-frequency ripple currents in power supply circuits and stabilize DC voltages in the system. Tantalum capacitors manufactured per military specifications (MIL-PRF-55365) are established reliability components and have less than 0.001% of failures per 1000 hours (the failure rate is less than 10 FIT) for grades D or S, thus positioning these parts among electronic components with the highest reliability characteristics. Still, failures of tantalum capacitors do happen and when it occurs it might have catastrophic consequences for the system. This is due to a short-circuit failure mode, which might be damaging to a power supply, and also to the capability of tantalum capacitors with manganese cathodes to self-ignite when a failure occurs in low-impedance applications. During such a failure, a substantial amount of energy is released by exothermic reaction of the tantalum pellet with oxygen generated by the overheated manganese oxide cathode, resulting not only in destruction of the part, but also in damage of the board and surrounding components. A specific feature of tantalum capacitors, compared to ceramic parts, is a relatively large value of capacitance, which in contemporary low-size chip capacitors reaches dozens and hundreds of microfarads. This might result in so-called surge current or turn-on failures in the parts when the board is first powered up. Such a failure, which is considered as the most prevalent type of failures in tantalum capacitors [I], is due to fast changes of the voltage in the circuit, dV/dt, producing high surge current spikes, I(sub sp) = Cx(dV/dt), when current in the circuit is unrestricted. These spikes can reach hundreds of amperes and cause catastrophic failures in the system. The mechanism of surge current failures has not been understood completely yet, and different hypotheses were discussed in relevant literature. These include a sustained scintillation

  11. Differential effects of continuous exposure to the investigational metastin/kisspeptin analog TAK-683 on pulsatile and surge mode secretion of luteinizing hormone in ovariectomized goats.

    Science.gov (United States)

    Tanaka, Tomomi; Ohkura, Satoshi; Wakabayashi, Yoshihiro; Kuroiwa, Takenobu; Nagai, Kiyosuke; Endo, Natsumi; Tanaka, Akira; Matsui, Hisanori; Kusaka, Masami; Okamura, Hiroaki

    2013-12-17

    The aim of the present study was to determine if the estradiol-induced luteinizing hormone (LH) surge is influenced by the constant exposure to TAK-683, an investigational metastin/kisspeptin analog, that had been established to depress the pulsatile gonadotropin-releasing hormone (GnRH) and LH secretion in goats. Ovariectomized goats subcutaneously received TAK-683 (TAK-683 group, n=6) or vehicle (control group, n=6) constantly via subcutaneous implantation of an osmotic pump. Five days after the start of the treatment, estradiol was infused intravenously in both groups to evaluate the effects on the LH surge. Blood samples were collected at 6-min intervals for 4 h prior to the initiation of either the TAK-683 treatment or the estradiol infusion, to determine the profiles of pulsatile LH secretion. They were also collected at 2-h intervals from -4 h to 32 h after the start of estradiol infusion for analysis of LH surges. The frequency and mean concentrations of LH pulses in the TAK-683 group were remarkably suppressed 5 days after the start of TAK-683 treatment compared with those of the control group (Psurge was observed in all animals of both groups. There were no significant differences in the LH concentrations for surge peak and the peak time of the LH surge between the TAK-683 and control groups. These findings suggest that the effects of continuous exposure to kisspeptin or its analog on the mechanism(s) that regulates the pulsatile and surge mode secretion of GnRH/LH are different in goats.

  12. L-arginine/nitric oxide amplifies the magnitude and duration of the luteinizing hormone surge induced by estrogen: involvement of neuropeptide Y.

    Science.gov (United States)

    Bonavera, J J; Kalra, P S; Kalra, S P

    1996-05-01

    Although estrogen can induce LH hypersecretion in ovariectomized (ovx) rats, the magnitude and duration of the LH surge are invariably far less than those of the preovulatory LH surge in cycling rats. Recently, the crucial roles of hypothalamic nitric oxide (NO) and neuropeptide Y (NPY) in the induction of LHRH and the LH surge have been recognized. In this study, we have tested the hypothesis that low grade stimulatory feedback effects of 17 beta-estradiol (E2) on LH secretion in ovx rats is due to a deficit in NO signaling. As the NO substrate, L-arginine (L-Arg), can enhance NO-dependent physiological responses, the effects of L-Arg on the LH surge in E2-primed ovx rats was studied. Ovx rats bearing permanent cannulas in the lateral cerebroventricle received 15-mm long SILASTIC capsules filled with E2 (300 micrograms/ml oil, s.c.) at 1000 h. Two days later, saline (SAL) or L-Arg (0.1 or 1 nmol in 5 microliters SAL) or D-Arg (1.0 nmol) was injected intracerebroventricularly every hour from 1100-1400. Blood samples were collected at 1100 h and at hourly intervals from 1400-1800 h via intraatrial cannulae implanted the day before. Whereas an expected moderate LH surge occurred in SAL-injected control rats, L-Arg, but not D-Arg, greatly augmented the magnitude and duration of the LH surge, with peak values attaining the range normally seen on proestrus. Furthermore, L-Arg (1 or 10.0 mM) and the NO donor, sodium nitroprusside (1 or 10.0 mM), stimulated the basal and K(+)-induced in vitro release of LHRH and NPY from the hypothalami of ovarian steroid-primed ovx rats. As NPY is stimulatory to LHRH release, we next tested the possibility that L-Arg/NO may initially stimulate NPY release in the hypothalamus, which, in turn, elicits LHRH discharge. E2-treated ovx rats receiving intracerebroventricular L-Arg were injected with antisense or missense oligodeoxynucleotides (oligos) to NPY-messenger RNA. Antisense, not missense, NPY oligos blocked the L

  13. Ovarian oestrogen-dependent maturation of the LH/FSH surge mechanism during prepubertal development in the gilt.

    Science.gov (United States)

    Foxcroft, G R; Elsaesser, F; Stickney, K; Haynes, N B; Back, H L

    1984-06-01

    An involvement of ovarian secretions and in particular oestradiol-17 beta in the maturation of the positive feedback mechanism controlling gonadotrophin surge secretion was studied in prepubertal gilts. The LH/FSH responses to an intramuscular injection of age- and body weight-related doses of oestradiol benzoate (OB) were compared in intact gilts at 60 days of age with or without oestradiol-17 beta pretreatment from 30 to 52 days of age. Four further groups of gilts were challenged with OB at 160 days and were intact, ovariectomized at 60 days, ovariectomized at 60 days and given oestrogen therapy from days 60 to 130 or ovariectomized at 130 days. A significant increase in the magnitude of LH surge responses to OB and a decrease in the time to the first consistent period of surge secretion in intact gilts at 160 compared to 60 days of age confirmed earlier studies and is considered to represent a real maturational change in positive feedback activity. A longer response interval was also present in the majority of ovariectomized gilts. Furthermore a significant reduction in the magnitude of OB-induced LH responses at day 160 occurred in gilts ovariectomized at day 60 compared to those ovariectomized at day 130 and with intact control animals. Oestrogen therapy after ovariectomy at day 60 effectively restored the magnitude of the LH response however. It is concluded that maturation of the positive feedback mechanism is ovarian, and probably oestrogen, dependent.

  14. Anisotropy of Magnetic Susceptibility (AMS) and Sedimentary Fabric Studies of Phreatomagmatic Surge Deposits, Hopi Buttes, Navajo Nation, NE Arizona

    Science.gov (United States)

    Newkirk, T. T.

    2005-12-01

    The Hopi Buttes volcanic field is a group of late Mio-Pliocene volcanic vents characterized by hydrovolcanic features. The volcanism at the Hopi Buttes produced ~300 maar and diatreme volcanic landforms scattered within an area of 50km in diameter. The maars in the area formed from phreatomagmatic explosions involving the interaction of the rapidly ascending monchiquitic/nephelinitic magmas and liquefied lower Bidahochi sediments, and groundwater. Phreatomagmatic eruptions produce a spectrum of pyroclastic density currents (i.e. "pyroclastic flows" or "pyroclastic surges/hydrovolcanic surges"). The direct products of these violent eruptive events are dilute gravity driven gas charged pyroclastic density currents. Which, over distances gain and/or lose competency due to a decreasing energy budget and/or paleotopographic control. Paleotopographic reconstructions of the Hopi Buttes volcanic field reveal a sub-horizontal playa type environment. This affords the opportunity to study individual surge deposits on the micro- to macroscopic scales to determine the emplacement dynamics of individual eruptive events without the complications of paleotopographic interference. Anisotropy of magnetic susceptibility and sedimentary fabric analysis has been used to examine the micro- to macroscopic fabrics of individual surge deposits at proximal, medial, and distal locations from the eruptive vent. These techniques give insight on the flow and depositional processes of the transient hydrovolcanic surges. Data shows a distinct correlation of microscopic AMS fabric changes to macroscopic sedimentary facies changes. At the proximal-medial interface ~150-200m AMS fabrics turn from chaotic/lack of orientation to a lineated fabric long axis perpendicular to flow direction. This fabric is interpreted to be transitional debulking interface from a highly concentrated rapid depositional flow to a more dilute transient flow, thus allowing the internal sorting and individual particles to

  15. Experimental investigations for provision of a data basis for optimization of active surge control. Final report; Experimentelle Untersuchungen zur Bereitstellung einer Datenbasis fuer die Optimierung der aktiven Stabilitaetsverbesserung. Teilverbund-Projekt: Aktive Stabilitaetsverbesserung - Analyseverfahren der Arbeitsgemeinschaft AG Turbo II. Abschlussbericht zum Vorhaben 1.1.4

    Energy Technology Data Exchange (ETDEWEB)

    Seume, J.; Reissner, A.

    2001-07-01

    Presently axial compressors have to run with considerable distance to operation points of high load although usually the best efficiencies can be obtained there. In those areas there is high danger of surge which brings high damaging potential to the compressor. The prediction time to surge presently is very short (<<1s) and depends on the load and rotor rotation of the compressor. The goal of this project is the production of a data basis to investigate stall inception (which is the precursor of surge) and to develop and test better precursory warning algorithms. An extensive set of data as well in stable as in unstable operating points in different load areas was developed which now is ready for use in research, verification and for comparison of forewarning systems. (orig.) [German] Zur Zeit ist es notwendig, Axialverdichter mit deutlichem Abstand von den hoch belasteten Betriebspunkten zu betreiben, obwohl haeufig dort die besten Wirkungsgrade zu erzielen waeren. In diesen Bereichen kann es leicht zu sog. Pumpen kommen, wodurch der Verdichter einem extremen Schaedigungspotential ausgesetzt ist. Die Vorwarnzeiten fuer das Pumpen sind bisher noch sehr kurz. Sie liegen in einem Bereich von deutlich weniger als einer Sekunde (abhaengig von der Belastung und der Drehzahl des Verdichters). Ziel dieser Untersuchungen ist es, eine Datenbasis zu liefern, anhand derer die Entstehungsmechanismen untersucht und moeglichst fruehzeitige Vorwarnalgorithmen entwickelt bzw. erprobt werden koennen. Es wurde eine umfangreiche Datenbasis sowohl an verschiedenen stabilen als auch instabilen Betriebspunkten in unterschiedlichen Lastbereichen erstellt, die nun zur Entwicklung, zur Verifizierung und zum Vergleich von Fruehwarnsystemen zur Verfuegung steht. (orig.)

  16. Cyclic steps due to the surge-type turbidity currents in flume experiments: effect of surge duration on the topography of steps

    Science.gov (United States)

    Yokokawa, Miwa; Yamano, Junpei; Miyai, Masatomo; Hughes Clarke, John; Izumi, Norihiro

    2017-04-01

    Field observations of turbidity currents and seabed topography on the Squamish delta in British Columbia, Canada revealed that cyclic steps formed by the surge-type turbidity currents (e.g., Hughes Clarke et al., 2014). The high-density portion of the flow, which affects the sea floor morphology, lasted only 30-60 seconds. We are doing flume experiments aiming to investigate the relationship between the condition of surges and topography of resultant steps. In this presentation, we are going to discuss about the effect of surge duration on the topography of steps. The experiments have been performed at Osaka Institute of Technology. A flume, which is 7.0 m long, 0.3 m deep and 2 cm wide, was suspended in a larger tank, which is 7.6 m long, 1.2 m deep and 0.3 m wide, filled with water. The inner flume tilted at 7 degrees. As a source of turbidity currents, mixture of salt water (1.17 g/cm^3) and plastic particles (1.3 g/cm^3, 0.1-0.18 mm in diameter) was prepared. The concentration of the sediments was 6.1 weight % (5.5 volume %) in the head tank. This mixture of salt water and plastic particles poured into the upstream end of the inner flume from head tank for 3 seconds or 7 seconds. 140 surges were made respectively. Discharge of the currents were fluctuated but range from 306 to 870 mL for 3s-surge, and from 1134 to 2030 mL for 7s-surge. As a result, five or six steps were formed respectively. At the case of 3s-surge, steps located at upstream portion of the flume moved vigorously toward upstream direction, whereas steps at downstream portion of the flume moved toward upstream direction at the case of 7s-surge. The wavelengths and wave heights of the steps by 3s-surge are larger than those of 7s-surge at the upstream portion of the flume, but the size of steps of 3s-surge are smaller than those of 7s-surge at the downstream portion of the flume. In this condition of slope and concentration, the longer surge duration, i.e. larger discharge of the current

  17. Vulnerability of Coastal Communities from Storm Surge and Flood Disasters.

    Science.gov (United States)

    Bathi, Jejal Reddy; Das, Himangshu S

    2016-02-19

    Disasters in the form of coastal storms and hurricanes can be very destructive. Preparing for anticipated effects of such disasters can help reduce the public health and economic burden. Identifying vulnerable population groups can help prioritize resources for the most needed communities. This paper presents a quantitative framework for vulnerability measurement that incorporates both socioeconomic and flood inundation vulnerability. The approach is demonstrated for three coastal communities in Mississippi with census tracts being the study unit. The vulnerability results are illustrated as thematic maps for easy usage by planners and emergency responders to assist in prioritizing their actions to vulnerable populations during storm surge and flood disasters.

  18. Research data supporting "Glacier surging in the West Kunlun Shan"

    OpenAIRE

    Chudley, Thomas R.; Willis, Ian C.

    2016-01-01

    Stacked Landsat 2 MSS (band 4, 60 m resolution), Landsat 5 TM (band 1, 30 m resolution), Landsat 7 ETM+ (band 8, 15 m resolution), and Landsat 8 OLI (band 8, 15 m resolution) imagery from 1972--2016, visualising the surges of 8 glaciers in the West Kunlun Shan, Xinjiang, China. Frames are annotated in the form YYYY_DDD, where YYYY is the year and DDD is the Julian day for that year. Information about location and scale of imagery can be found in the appendix of the related Master's thesis. La...

  19. Surge Nozzle NDE Specimen Mechanical Stress Improvement Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fredette, Lee F.

    2011-07-14

    The purpose of this project was to perform a finite element analysis of a pressurized water reactor pressurizer surge nozzle mock-up to predict both the weld residual stresses created in its construction and the final stress state after the application of the Mechanical Stress Improvement Process (MSIP). Strain gages were applied to the inner diameter of the mock-up to record strain changes during the MSIP. These strain readings were used in an attempt to calculate the final stress state of the mock-up as well.

  20. Vulnerability of Coastal Communities from Storm Surge and Flood Disasters

    Science.gov (United States)

    Bathi, Jejal Reddy; Das, Himangshu S.

    2016-01-01

    Disasters in the form of coastal storms and hurricanes can be very destructive. Preparing for anticipated effects of such disasters can help reduce the public health and economic burden. Identifying vulnerable population groups can help prioritize resources for the most needed communities. This paper presents a quantitative framework for vulnerability measurement that incorporates both socioeconomic and flood inundation vulnerability. The approach is demonstrated for three coastal communities in Mississippi with census tracts being the study unit. The vulnerability results are illustrated as thematic maps for easy usage by planners and emergency responders to assist in prioritizing their actions to vulnerable populations during storm surge and flood disasters. PMID:26907313

  1. Vulnerability of Coastal Communities from Storm Surge and Flood Disasters

    Directory of Open Access Journals (Sweden)

    Jejal Reddy Bathi

    2016-02-01

    Full Text Available Disasters in the form of coastal storms and hurricanes can be very destructive. Preparing for anticipated effects of such disasters can help reduce the public health and economic burden. Identifying vulnerable population groups can help prioritize resources for the most needed communities. This paper presents a quantitative framework for vulnerability measurement that incorporates both socioeconomic and flood inundation vulnerability. The approach is demonstrated for three coastal communities in Mississippi with census tracts being the study unit. The vulnerability results are illustrated as thematic maps for easy usage by planners and emergency responders to assist in prioritizing their actions to vulnerable populations during storm surge and flood disasters.

  2. Coastal Flooding Hazards due to storm surges and subsidence

    DEFF Research Database (Denmark)

    Sørensen, Carlo; Knudsen, Per; Andersen, Ole B.

    Flooding hazard and risk mapping are major topics in low-lying coastal areas before even considering the adverse effects of sea level rise (SLR) due to climate change. While permanent inundation may be a prevalent issue, more often floods related to extreme events (storm surges) have the largest...... damage potential.Challenges are amplified in some areas due to subsidence from natural and/or anthropogenic causes. Subsidence of even a few mm/y may over time greatly impair the safety against flooding of coastal communities and must be accounted for in order to accomplish the economically most viable...

  3. Multidecadal Scale Detection Time for Potentially Increasing Atlantic Storm Surges in a Warming Climate

    Science.gov (United States)

    Lee, Benjamin Seiyon; Haran, Murali; Keller, Klaus

    2017-10-01

    Storm surges are key drivers of coastal flooding, which generate considerable risks. Strategies to manage these risks can hinge on the ability to (i) project the return periods of extreme storm surges and (ii) detect potential changes in their statistical properties. There are several lines of evidence linking rising global average temperatures and increasingly frequent extreme storm surges. This conclusion is, however, subject to considerable structural uncertainty. This leads to two main questions: What are projections under various plausible statistical models? How long would it take to distinguish among these plausible statistical models? We address these questions by analyzing observed and simulated storm surge data. We find that (1) there is a positive correlation between global mean temperature rise and increasing frequencies of extreme storm surges; (2) there is considerable uncertainty underlying the strength of this relationship; and (3) if the frequency of storm surges is increasing, this increase can be detected within a multidecadal timescale (≈20 years from now).

  4. Degassing of air bubbles in a chamber surge tank; Entgasung in einem Kammerwasserschloss

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Wolfgang; Schneider, Josef; Zenz, Gerald [Technische Univ. Graz (Austria). Inst. fuer Wasserbau Wasserwirtschaft; Kolb, Stephan [Schluchseewerk AG, Laufenburg (Germany)

    2012-07-01

    Increased flexibility for pumped hydro schemes with high discharge rates requires an optimized surge tank design. The objective of the surge tank layout is to protect the pressure tunnel from water hammer propagation and reduce mass oscillation due operational needs. In past decades surge tanks became more and more sophisticated to fulfill technical as well as economic aspects. Therefore the design of chamber surge tanks has been adapted with throtties and overflows to make use of differential effects. These are initiated during down-surge by water column separation. In the main shaft the water column is dropping through water still remains in the upper chamber which causes high air entrainment. It is important to avoid the transport of air into the pressure tunnel. The optimization of a large surge tank based on physical model tests supported by 3D-numerical calculation is demonstrated. (orig.)

  5. Simulation of Wind Speed in the Ventilation Tunnel for Surge Tanks in Transient Processes

    OpenAIRE

    Jiandong Yang; Huang Wang; Wencheng Guo; Weijia Yang; Wei Zeng

    2016-01-01

    Hydroelectric power plants' open-type surge tanks may be built in mountains subject to the provision of atmospheric air. Hence, a ventilation tunnel is indispensable. The air flow in the ventilation tunnel is associated with the fluctuation of water-level in the surge tank. There is a great relationship between the wind speed and the safe use and project investment of ventilation tunnels. To obtain the wind speed in a ventilation tunnel for a surge tank during transient processes, this articl...

  6. Characteristics and possibilities of software tool for metal-oxide surge arresters selection

    Directory of Open Access Journals (Sweden)

    Đorđević Dragan

    2012-01-01

    Full Text Available This paper presents a procedure for the selection of metal-oxide surge arresters based on the instructions given in the Siemens and ABB catalogues, respecting their differences and the characteristics and possibilities of the software tool. The software tool was developed during the preparation of a Master's thesis titled, 'Automation of Metal-Oxide Surge Arresters Selection'. An example is presented of the selection of metal-oxide surge arresters using the developed software tool.

  7. Surge Deposits and Disaster Record induced by Mt. Bandai 1888 Eruption

    OpenAIRE

    紺谷, 和生; 谷口, 宏充; コンタニ, カズオ; タニグチ, ヒロミツ; KONTANI, Kazuo; TANIGUCHI, Hiromitsu

    2004-01-01

    Mt. Bandai (Bandai-san), famous for the large-scale collapse of a volcanic edifice triggered by a phreatic eruption on July 15, 1888, is an active volcano in Fukushima Prefecture. The phreatic eruption produced a pyroclastic surge, and which hit villages on the eastern foot of Mt. Bandai. Precious studies have focused on the surge deposit, and have showed the characteristics of the pyroclastic surge and yielded an eruption model. However, there are many paradoxes between the models arrived at...

  8. Association between the rate of the morning surge in blood pressure and cardiovascular events and stroke.

    Science.gov (United States)

    Luo, Yu; Wang, Yan-li; Wu, Ying-biao; Xu, Yao; Head, Geoffrey A; Barry, Macgrathy; Liang, Yu-lu

    2013-02-01

    The exaggerated surge in morning blood pressure (BP) that many patients experience upon awakening may be closely related to target organ damage and may be a predictor of cardiovascular complications. However, no previous studies have evaluated the rate of this surge independently of the evening period. It remains unclear whether the rate of increase experienced during the surge is a significant or independent determinant of cardiovascular events. We randomly selected 340 ambulatory BP monitoring (ABPM) patients. All subjects without type 2 diabetes mellitus were divided into two groups: hypertensive group (n = 170) and normotensive group (n = 170). We analyzed ambulatory blood pressure recordings using a double logistic curve-fitting procedure to determine whether the magnitude of the surge in BP and heart rate (HR) in the morning is related to the level of BP in hypertensive individuals. We evaluated the association between the rate of the morning surge in systolic BP (SBP) and the incidence of myocardial infarction and stroke in normotensive and hypertensive subjects. Comparisons between hypertensive and normotensive subjects showed that the rates of the morning surges in SBP, mean BP (MBP), and diastolic BP (DBP) were greater in the hypertensive group (P surge in BP was found to be correlated with the daytime SBP (r = 0.236, P surge in SBP was closely correlated with daytime SBP (r = 0.463, P surge in SBP was an independent determinant of myocardial infarction (OR = 1.266, 95% CI = 1.153 - 1.389, P surge in BP is greater in hypertensive subjects than in normotensive subjects. Daytime SBP may be the best predictor of the rate of morning surge in SBP. The rate of the morning surge in BP is associated with cardiovascular and stroke events.

  9. Mapping and Visualization of Storm-Surge Dynamics for Hurricane Katrina and Hurricane Rita

    Science.gov (United States)

    Gesch, Dean B.

    2009-01-01

    The damages caused by the storm surges from Hurricane Katrina and Hurricane Rita were significant and occurred over broad areas. Storm-surge maps are among the most useful geospatial datasets for hurricane recovery, impact assessments, and mitigation planning for future storms. Surveyed high-water marks were used to generate a maximum storm-surge surface for Hurricane Katrina extending from eastern Louisiana to Mobile Bay, Alabama. The interpolated surface was intersected with high-resolution lidar elevation data covering the study area to produce a highly detailed digital storm-surge inundation map. The storm-surge dataset and related data are available for display and query in a Web-based viewer application. A unique water-level dataset from a network of portable pressure sensors deployed in the days just prior to Hurricane Rita's landfall captured the hurricane's storm surge. The recorded sensor data provided water-level measurements with a very high temporal resolution at surveyed point locations. The resulting dataset was used to generate a time series of storm-surge surfaces that documents the surge dynamics in a new, spatially explicit way. The temporal information contained in the multiple storm-surge surfaces can be visualized in a number of ways to portray how the surge interacted with and was affected by land surface features. Spatially explicit storm-surge products can be useful for a variety of hurricane impact assessments, especially studies of wetland and land changes where knowledge of the extent and magnitude of storm-surge flooding is critical.

  10. The Use of a Statistical Model of Storm Surge as a Bias Correction for Dynamical Surge Models and its Applicability along the U.S. East Coast

    Directory of Open Access Journals (Sweden)

    Haydee Salmun

    2015-02-01

    Full Text Available The present study extends the applicability of a statistical model for prediction of storm surge originally developed for The Battery, NY in two ways: I. the statistical model is used as a biascorrection for operationally produced dynamical surge forecasts, and II. the statistical model is applied to the region of the east coast of the U.S. susceptible to winter extratropical storms. The statistical prediction is based on a regression relation between the “storm maximum” storm surge and the storm composite significant wave height predicted ata nearby location. The use of the statistical surge prediction as an alternative bias correction for the National Oceanic and Atmospheric Administration (NOAA operational storm surge forecasts is shownhere to be statistically equivalent to the existing bias correctiontechnique and potentially applicable for much longer forecast lead times as well as for storm surge climate prediction. Applying the statistical model to locations along the east coast shows that the regression relation can be “trained” with data from tide gauge measurements and near-shore buoys along the coast from North Carolina to Maine, and that it provides accurate estimates of storm surge.

  11. Vulnerability assessment of storm surges in the coastal area of Guangdong Province

    Directory of Open Access Journals (Sweden)

    K. Li

    2011-07-01

    Full Text Available Being bordered by the South China Sea and with long coastline, the coastal zone of Guangdong Province is often under severe risk of storm surges, as one of a few regions in China which is seriously threatened by storm surges. This article systematically analyzes the vulnerability factors of storm surges in the coastal area of Guangdong (from Yangjing to Shanwei. Five vulnerability assessment indicators of hazard-bearing bodies are proposed, which are social economic index, land use index, eco-environmental index, coastal construction index, and disaster-bearing capability index. Then storm surge vulnerability assessment index system in the coastal area of Guangdong is established. Additionally, the international general mode about coastal vulnerability assessment is improved, and the vulnerability evolution model of storm surges in the coastal area of Guangdong is constructed. Using ArcGIS, the vulnerability zoning map of storm surges in the study region is drawn. Results show that there is the highest degree of storm surge vulnerability in Zhuhai, Panyu, and Taishan; second in Zhongshan, Dongguan, Huiyang, and Haifeng; third in Jiangmen, Shanwei, Yangjiang, and Yangdong; fourth in Baoan, Kaiping, and Enping; and lowest in Guangzhou, Shunde, Shenzhen, and Longgang. This study on the risk of storm surges in these coastal cities can guide the land use of coastal cities in the future, and provide scientific advice for the government to prevent and mitigate the storm surge disasters. It has important theoretical and practical significance.

  12. A Comparison of Ensemble Kalman Filters for Storm Surge Assimilation

    KAUST Repository

    Altaf, Muhammad

    2014-08-01

    This study evaluates and compares the performances of several variants of the popular ensembleKalman filter for the assimilation of storm surge data with the advanced circulation (ADCIRC) model. Using meteorological data from Hurricane Ike to force the ADCIRC model on a domain including the Gulf ofMexico coastline, the authors implement and compare the standard stochastic ensembleKalman filter (EnKF) and three deterministic square root EnKFs: the singular evolutive interpolated Kalman (SEIK) filter, the ensemble transform Kalman filter (ETKF), and the ensemble adjustment Kalman filter (EAKF). Covariance inflation and localization are implemented in all of these filters. The results from twin experiments suggest that the square root ensemble filters could lead to very comparable performances with appropriate tuning of inflation and localization, suggesting that practical implementation details are at least as important as the choice of the square root ensemble filter itself. These filters also perform reasonably well with a relatively small ensemble size, whereas the stochastic EnKF requires larger ensemble sizes to provide similar accuracy for forecasts of storm surge.

  13. Analysis of surge line MBLOCA sequences with HPSI failed

    Energy Technology Data Exchange (ETDEWEB)

    Queral, C.; Gonzalez-Cadelo, J.; Prada, D.; Montero, J. [Univ. Politecnica de Madrid, Madrid (Spain); Martinez-Murillo, J.C. [Almaraz-Trillo (United Arab Emirates); Perez, J. [Consejo de Seguridad Nuclear, Madrid (Spain)

    2011-07-01

    The main objective of OECD/NEA ROSA-2 Project is to analyze thermal-hydraulic issues relevant to light water reactors (LWR) safety by using Large Scale Test Facility (LSTF) . As a part of this project ROSA-2 test1 has been performed in LSTF during 2009. This test consists of a double ended guillotine break in the surge line, surge line loss-of-coolant accident (SL-LOCA), with high pressure safety injection, (HPSI) failed and reactor coolant pumps trip simultaneously to reactor scram. As part of the participation of Universidad Politecnica de Madrid (UPM) group in OECD/NEA ROSA-2 and Code Applications and Maintenance Program (CAMP) projects two tasks related with this test have been performed. In the first task the simulation of ROSA-2 test1 has been performed with TRAC/RELAP Advanced Computational Engine (TRACE) code. Furthermore, an analysis of similar sequences in a Westinghouse pressurized water reactor (PWR) has been carried out; within this analysis a wide range of break area size has been analyzed: from 0.0254 m to 0.2794 m (1 to 11 inches), and a sensitivity analysis of delay time in the beginning of manual depressurization in the secondary side has been performed. The results show that the sequences with intermediate break sizes, from 0.0508 m to 0.1016 m (2 to 4 inches) have worse consequences in this kind of sequences. (author)

  14. Improving surge capacity for biothreats: experience from Taiwan.

    Science.gov (United States)

    Shih, Fuh-Yuan; Koenig, Kristi L

    2006-11-01

    This article discusses Taiwan's experience in managing surge needs based on recent events, including the 1999 earthquake, severe acute respiratory syndrome in 2003, airliner crashes in 1998 and 2001, and yearly typhoons and floods. Management techniques are compared and contrasted with U.S. approaches. The authors discuss Taiwan's practices of sending doctors to the scene of an event and immediately recalling off-duty hospital personnel, managing volunteers, designating specialty hospitals, and use of incident management systems. The key differences in bioevents, including the mathematical myths regarding individual versus population care, division of stockpiles, the Maginot line, and multi-jurisdictional responses, are highlighted. Several recent initiatives aimed at mitigating biothreats have begun in Taiwan, but their efficacy has not yet been tested. These include the integration of the emergency medical services and health-facility medical systems with other response systems; the use of the hospital emergency incident command system; crisis risk-communications approaches; and the use of practical, hands-on training programs. Other countries may gain valuable insights for mitigating and managing biothreats by studying Taiwan's experiences in augmenting surge capacity.

  15. Dependence between sea surge, river flow and precipitation in south and west Britain

    Directory of Open Access Journals (Sweden)

    C. Svensson

    2004-01-01

    Full Text Available Estuaries around Great Britain may be at heightened risk of flooding because of the simultaneous occurrence of extreme sea surge and river flow, both of which may be caused by mid-latitude cyclones. A measure especially suited for extremes was employed to estimate dependence between river flow and sea surge. To assist in the interpretation of why flow-surge dependence occurs in some areas and not in others, the dependence between precipitation and surge and between precipitation and river flow was also studied. Case studies of the meteorological situations leading to high surges and/or river flows were also carried out. The present study concerns catchments draining to the south and west coasts of Great Britain. Statistically significant dependence between river flow and daily maximum sea surge may be found at catchments spread along most of this coastline. However, higher dependence is generally found in catchments in hilly areas with a southerly to westerly aspect. Here, precipitation in south-westerly airflow, which is generally the quadrant of prevailing winds, will be enhanced orographically as the first higher ground is encountered. The sloping catchments may respond quickly to the abundant rainfall and the flow peak may arrive in the estuary on the same day as a large sea surge is produced by the winds and low atmospheric pressure associated with the cyclone. There are three regions where flow-surge dependence is strong: the western part of the English south coast, southern Wales and around the Solway Firth. To reduce the influence of tide-surge interaction on the dependence analysis, the dependence between river flow and daily maximum surge occurring at high tide was estimated. The general pattern of areas with higher dependence is similar to that using the daily maximum surge. The dependence between river flow and daily maximum sea surge is often strongest when surge and flow occur on the same day. The west coast from Wales and

  16. Spatial and temporal variability and long-term trends in skew surges globally

    Directory of Open Access Journals (Sweden)

    Robert eMawdsley

    2016-03-01

    Full Text Available Storm surges and the resulting extreme high sea levels are among the most dangerous natural disasters and are responsible for widespread social, economic and environmental consequences. Using a set of 220 tide gauges, this paper investigates the temporal variations in storm surges around the world and the spatial coherence of its variability. We compare results derived from two parameters used to represent storm surge: skew surge and the more traditional, non-tidal residual. We determine the extent of tide-surge interaction, at each study site, and find statistically significant (95% confidence levels of tide-surge interaction at 59% of sites based on tidal level and 81% of sites based on tidal-phase. The tide-surge interaction was strongest in regions of shallow bathymetry such as the North Sea, north Australia and the Malay Peninsula. At most sites the trends in the skew surge time series were similar to those of non-tidal residuals, but where there were large differences in trends, the sites tended to have a large tidal range. Only 13% of sites had a statistically significant trend in skew surge, and of these approximately equal numbers were positive and negative. However, for trends in the non-tidal residual there are significantly more negative trends. We identified 8 regions where there were strong positive correlations in skew surge variability between sites, which meant that a regional index could be created to represent these groups of sites. Despite, strong correlations between some regional skew surge indices, none are significant at the 95% level, however, at the 80% level there was significant positive correlation between the north-west Atlantic - south and the North Sea. Correlations between the regional skew surge indices and climate indices only became significant at the 80% level, where Nińo 4 was positively correlated with the Gulf of Mexico skew surge index and negatively correlated with the east Australia skew surge index

  17. Comparison of two recent storm surge events based on results of field surveys

    Science.gov (United States)

    Nakamura, Ryota; Shibayama, Tomoya; Mikami, Takahito; Esteban, Miguel; Takagi, Hiroshi; Maell, Martin; Iwamoto, Takumu

    2017-10-01

    This paper compares two different types of storm surge disaster based on field surveys. Two cases: a severe storm surge flood with its height of over 5 m due to Typhoon Haiyan (2013) in Philippine, and inundation of storm surge around Nemuro city in Hokkaido of Japan with its maximum surge height of 2.8 m caused by extra-tropical cyclone are taken as examples. For the case of the Typhoon Haiyan, buildings located in coastal region were severely affected due to a rapidly increase in ocean surface. The non-engineering buildings were partially or completely destroyed due to their debris transported to an inner bay region. In fact, several previous reports indicated two unique features, bore-like wave and remarkably high speed currents. These characteristics of the storm surge may contribute to a wide-spread corruption for the buildings around the affected region. Furthermore, in the region where the surge height was nearly 3 m, the wooden houses were completely or partially destroyed. On the other hand, in Nemuro city, a degree of suffering in human and facility caused by the storm surge is minor. There was almost no partially destroyed residential houses even though the height of storm surge reached nearly 2.8 m. An observation in the tide station in Nemuro indicated that this was a usual type of storm surge, which showed a gradual increase of sea level height in several hours without possessing the unique characteristics like Typhoon Haiyan. As a result, not only the height of storm surge but also the robustness of the buildings and characteristics of storm surge, such as bore like wave and strong currents, determined the existent of devastation in coastal regions.

  18. Increased Level of Morning Surge in Blood Pressure in Normotensives: ACross-Sectional Study from Pakistan.

    Science.gov (United States)

    Almas, Aysha; Sultan, Fatehali Tipoo; Kazmi, Khawar

    2016-10-01

    To determine the mean morning surge (MS) in blood pressure, the frequency of increased morning surge in normotensive subjects, and to compare those with morning surge with those without MS. Across-sectional, comparative study. The Department of Medicine, The Aga Khan University Hospital, Karachi, from April 2011 to March 2012. Adult normotensive healthy volunteers aged 35 to 65 years were inducted. Their ambulatory blood pressure (ABP) was measured over a 24-hour period, using digital ambulatory blood pressure monitors. Morning surge was calculated as the average of four readings after waking minus the lowest three nocturnal readings. Increased morning surge was defined as > 11 mm Hg in systolic (SBP) or > 12 mm Hg in diastolic (DBP). Dipping was defined as > 10% dipping in blood pressure. Eighty-two healthy volunteers were recruited. Their mean age was 36.9 ±1.2 years; 74.4 (61%) were men, and 58.5 (48%) woke up for morning prayers. Mean overall SBPwas 113 ±1.6 mm Hg, overall DBPwas 73.9 ±0.7 mm Hg, and overall heart rate was 75 (10) beats/minute. Mean morning surge was 17.6 ±1.0 mm Hg in SBPand 16.0 ±0.8 mm Hg in DBP. The frequency of increased morning surge was 66 (80.5%) in SBP, and 57 (69%) in DBP. On comparison of participants with normal morning surge and increased morning surge in SBP, there was a significant difference in nondipping status (13.4% in normal vs. 18.3% in increased morning surge, p= 0.001). Mean morning surge in SBPand DBPare relatively higher in this subset population in a tertiary care center in Pakistan. These values are higher than those reported in the literature.

  19. Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

    Science.gov (United States)

    Azizi, Mohammad Ali; Brouwer, Jacob

    2017-10-01

    A better understanding of turbulent unsteady flows in gas turbine systems is necessary to design and control compressors for hybrid fuel cell-gas turbine systems. Compressor stall/surge analysis for a 4 MW hybrid solid oxide fuel cell-gas turbine system for locomotive applications is performed based upon a 1.7 MW multi-stage air compressor. Control strategies are applied to prevent operation of the hybrid SOFC-GT beyond the stall/surge lines of the compressor. Computational fluid dynamics tools are used to simulate the flow distribution and instabilities near the stall/surge line. The results show that a 1.7 MW system compressor like that of a Kawasaki gas turbine is an appropriate choice among the industrial compressors to be used in a 4 MW locomotive SOFC-GT with topping cycle design. The multi-stage radial design of the compressor enhances the ability of the compressor to maintain air flow rate during transient step-load changes. These transient step-load changes are exhibited in many potential applications for SOFC/GT systems. The compressor provides sustained air flow rate during the mild stall/surge event that occurs due to the transient step-load change that is applied, indicating that this type of compressor is well-suited for this hybrid application.

  20. Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M.; Yu, Yi-Hsiang; Wright, Alan D.; Lawson, Michael

    2016-06-01

    The aim of this paper is to describe how to control the power-to-load ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the time-averaged power, but to also consider the power-take-off (PTO) torque and foundation forces that arise because of WEC motion. The objective function of the controller will include competing terms that force the controller to balance power capture with structural loading. Separate penalty weights were placed on the surge-foundation force and PTO torque magnitude, which allows the controller to be tuned to emphasize either power absorption or load shedding. Results of this study found that, with proper selection of penalty weights, gains in time-averaged power would exceed the gains in structural loading while minimizing the reactive power requirement.

  1. Storm surge in the Bay of Bengal and Arabian Sea: The problem and its prediction

    Digital Repository Service at National Institute of Oceanography (India)

    Dube, S.K.; Rao, A.D.; Sinha, P.C.; Murty, T.S.; Bahulayan, N.

    to annual economic losses in these countries. Thus, the real time monitoring and warning of storm surge is of great concern for this region. The goal of this paper is to provide an overview of major aspects of the storm surge problem in the Bay of Bengal...

  2. ISSN 2073 ISSN 2073 ISSN 2073-9990 East Cent. Afr. J. surg.

    African Journals Online (AJOL)

    Prof Kakande

    Figure 1. Necrotic Fascia with Min. 92. ISSN 2073. ISSN 2073-9990 East Cent. Afr. J. surg. (Online). 9990 East Cent. Afr. J. surg. (Online). East and Central African Journal of Surgery. July/August 2012 Volume. East and Central African Journal of Surgery. July/August 2012 Volume 17 (2) assim University , Saudi Arabia.

  3. Factors guiding tsunami surge at the Nagapattinam–Cuddalore shelf, Tamil Nadu, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Murthy, K.S.R.; Subrahmanyam, A.S.; Murty, G.P.S.; Sarma, K.V.L.N.S.; Subrahmanyam, V.; Rao, K.M.; Rani, P.S.; Anuradha, A.; Adilakshmi, B.; Devi, T.S.

    The Tamil Nadu margin, in particular the Nagapattinam–Cuddalore shelf was the worst affected by the tsunami surge and inundation caused by the great Sumatra earthquake of 26 December 2004 (Mw 9.3). Surge heights in this part were of the order of 2...

  4. Role of exogenous estrogen in initiation of estrus and induction of an LH surge

    Science.gov (United States)

    Among cattle the LH surge that causes ovulation occurs shortly after the onset of a spontaneous estrus. In addition an injection of 100 'g of GnRH can induce an LH surge capable of inducing ovulation. We hypothesized that different preovulatory estradiol profiles would result in different ovulator...

  5. Research of the surge voltage protection by means of Hybrid Real-Time Power System Simulator

    Directory of Open Access Journals (Sweden)

    Stavitsky Sergey

    2017-01-01

    Full Text Available The article considers the simulation of surge voltage protection. A functional diagram of this protection model and the means by which the researches were made are presented. The results are the oscillograms of the surge voltage protection operation for the generator.

  6. Artificial Neural Network forecasting of storm surge water levels at major estuarine ports to supplement national tide-surge models and improve port resilience planning

    Science.gov (United States)

    French, Jon; Mawdsley, Robert; Fujiyama, Taku; Achuthan, Kamal

    2017-04-01

    Effective prediction of tidal storm surge is of considerable importance for operators of major ports, since much of their infrastructure is necessarily located close to sea level. Storm surge inundation can damage critical elements of this infrastructure and significantly disrupt port operations and downstream supply chains. The risk of surge inundation is typically approached using extreme value analysis, while short-term forecasting generally relies on coastal shelf-scale tide and surge models. However, extreme value analysis does not provide information on the duration of a surge event and can be sensitive to the assumptions made and the historic data available. Also, whilst regional tide and surge models perform well along open coasts, their fairly coarse spatial resolution means that they do not always provide accurate predictions for estuarine ports. As part of a NERC Environmental Risks to Infrastructure Innovation Programme project, we have developed a tool that is specifically designed to forecast the North Sea storm surges on major ports along the east coast of the UK. Of particular interest is the Port of Immingham, Humber estuary, which handles the largest volume of bulk cargo in the UK including major flows of coal and biomass for power generation. A tidal surge in December 2013, with an estimated return period of 760 years, partly flooded the port, damaged infrastructure and disrupted operations for several weeks. This and other recent surge events highlight the need for additional tools to supplement the national UK Storm Tide Warning Service. Port operators are also keen to have access to less computationally expensive forecasting tools for scenario planning and to improve their resilience to actual events. In this paper, we demonstrate the potential of machine learning methods based on Artificial Neural Networks (ANNs) to generate accurate short-term forecasts of extreme water levels at estuarine North Sea ports such as Immingham. An ANN is

  7. Determining Storm Surge Return Periods: The Use of Evidence of Historic Events

    DEFF Research Database (Denmark)

    Madsen, Kristine S.; Sørensen, Carlo Sass; Schmith, Torben

    Storm surges are a major concern for many coastal communities, and rising levels of surges is a key concern in relation to climate change. The sea level of a statistical 100-year or 1000-year storm surge event and similar statistical measures are used for spatial planning and emergency preparedness....... These statistics are very sensitive to the assessments of past events, and to future sea level change. The probability of a major storm surge from the Baltic Sea hitting the Copenhagen metropolitan area is officially determined by the Danish Coastal Authority based on tide gauge records. We have a long history...... for tide gauge measurements, with 120 years of data available for the calculations. However, the oldest of these tide gauge stations was set up after a major storm surge in 1872, and no events of similar severity have occurred since. Including the evidence of the historic events from the 18th century...

  8. Quantification of Sediment Transport During Glacier Surges and its Impact on Landform Architecture

    DEFF Research Database (Denmark)

    Kjær, Kurt H.; Schomacker, Anders; Korsgaard, Niels Jákup

    architecture occurs distal to the 1810 ice margin, where the 1890 surge advanced over hitherto undeformed sediments. Proximal to the 1810 ice margin, the landscape have been transgressed by either one or two glaciers (in 1890 and 1964). The most complex landscape architecture is found proximal to the 1964 ice......Eos Trans. AGU, 89(53), Fall Meet. Suppl., Abstract C23A-0580 Multi-temporal DEMs (Digital Elevation Models) of glaciers and ice streams have successfully been used for extraction of changes in ice volume over time. In this study, we analysed DEMs of the Brúarjökull glacier forefield (Iceland......) for 1945, prior to the last surge in 1964, and for 2003 in order to assess the effect of the surge on the sediment architecture in the forefield. The pre- and post-surge DEMs allow direct quantification of the sediment volumes that were re-distributed in the forefield by the surging ice mass in 1964...

  9. Local amplification of storm surge by Super Typhoon Haiyan in Leyte Gulf.

    Science.gov (United States)

    Mori, Nobuhito; Kato, Masaya; Kim, Sooyoul; Mase, Hajime; Shibutani, Yoko; Takemi, Tetsuya; Tsuboki, Kazuhisa; Yasuda, Tomohiro

    2014-07-28

    Typhoon Haiyan, which struck the Philippines in November 2013, was an extremely intense tropical cyclone that had a catastrophic impact. The minimum central pressure of Typhoon Haiyan was 895 hPa, making it the strongest typhoon to make landfall on a major island in the western North Pacific Ocean. The characteristics of Typhoon Haiyan and its related storm surge are estimated by numerical experiments using numerical weather prediction models and a storm surge model. Based on the analysis of best hindcast results, the storm surge level was 5-6 m and local amplification of water surface elevation due to seiche was found to be significant inside Leyte Gulf. The numerical experiments show the coherent structure of the storm surge profile due to the specific bathymetry of Leyte Gulf and the Philippines Trench as a major contributor to the disaster in Tacloban. The numerical results also indicated the sensitivity of storm surge forecast.

  10. Planning for a medical surge incident: Is rehabilitation the missing link?

    Science.gov (United States)

    Vonderschmidt, Kay

    2017-01-01

    This mixed methods study explored surge planning for patients who will need rehabilitative care after a mass casualty incident. Planning for a patient surge incident typically considers only prehospital and hospital care. However, in many cases, disaster patients need rehabilitation for which planning is often overlooked. The purpose of this study was to explore this hidden dimension of patient rehabilitation for surge planning and preparedness and ask: 1. To what extent can an analysis of standard patient acuity assessment tools [Simple Triage and Rapid Treatment and Injury Severity Score] be used to project future demand for admission to rehabilitative care? 2. What improvements to medical disaster planning are needed to address patient surge related to rehabilitation? This study found that standard patient benchmarks can be used to project demand for rehabilitation following a mass casualty incident, and argues that a reconceptualization of surge planning to include rehabilitation would improve medical disaster planning.

  11. Directional Storm Surge in Enclosed Seas: The Red Sea, the Adriatic, and Venice

    Directory of Open Access Journals (Sweden)

    Carl Drews

    2015-05-01

    Full Text Available Storm surge is dependent on wind direction, with maximum surge heights occurring when strong winds blow onshore. It is less obvious what happens when a port city is situated at the end of a long narrow gulf, like Venice at the northwestern end of the Adriatic Sea. Does the narrow marine approach to the port city limit the dangerous wind direction to a span of only a few degrees? This modeling study shows that the response in surge height to wind direction is a sinusoidal curve for port cities at the end of a long inlet, as well as for cities exposed along a straight coastline. Surge height depends on the cosine of the angle between the wind direction and the major axis of the narrow gulf. There is no special protection from storm surge afforded by a narrow ocean-going approach to a port city.

  12. Morning blood pressure surge is associated with arterial stiffness and sympathetic baroreflex sensitivity in hypertensive seniors.

    Science.gov (United States)

    Okada, Yoshiyuki; Galbreath, M Melyn; Shibata, Shigeki; Jarvis, Sara S; Bivens, Tiffany B; Vongpatanasin, Wanpen; Levine, Benjamin D; Fu, Qi

    2013-09-15

    Morning blood pressure (BP) surge is considered to be an independent risk factor for cardiovascular diseases. We tested the hypothesis that increased large-artery stiffness and impaired sympathetic baroreflex sensitivity (BRS) contribute to augmented morning surge in elderly hypertensive subjects. Morning surge was assessed as morning systolic BP averaged for 2 h just after waking up minus minimal sleeping systolic BP by using ambulatory BP monitoring (ABPM) in 40 untreated hypertensive [68 ± 1 (SE) yr] and 30 normotensive (68 ± 1 yr) subjects. Beat-by-beat finger BP and muscle sympathetic nerve activity (MSNA) were recorded in the supine position and at 60° upright tilt. We assessed arterial stiffness with carotid-to-femoral pulse wave velocity (cfPWV) and sympathetic BRS during spontaneous breathing. Awake and asleep ABPM-BPs and morning surge were higher in hypertensive than normotensive subjects (all P surge ≥35 mmHg (median value) had higher cfPWV (11.9 ± 0.5 vs. 9.9 ± 0.4 m/s, P = 0.002) and lower sympathetic BRS (supine: -2.71 ± 0.25 vs. -3.73 ± 0.29, P = 0.011; upright: -2.62 ± 0.22 vs. -3.51 ± 0.35 bursts·100 beats(-1)·mmHg(-1), P = 0.052) than those with morning surge 0.05), while upright total peripheral resistance was higher in hypertensive subjects with greater morning surge than those with lesser morning surge (P = 0.050). Morning surge was correlated positively with cfPWV (r = 0.59, P surge is associated with arterial stiffness and sympathetic BRS, as well as vasoreactivity during orthostasis in hypertensive seniors.

  13. The Increase in Signaling by Kisspeptin Neurons in the Preoptic Area and Associated Changes in Clock Gene Expression That Trigger the LH Surge in Female Rats Are Dependent on the Facilitatory Action of a Noradrenaline Input.

    Science.gov (United States)

    Kalil, Bruna; Ribeiro, Aline B; Leite, Cristiane M; Uchôa, Ernane T; Carolino, Ruither O; Cardoso, Thais S R; Elias, Lucila L K; Rodrigues, José A; Plant, Tony M; Poletini, Maristela O; Anselmo-Franci, Janete A

    2016-01-01

    In rodents, kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3V) of the preoptic area are considered to provide a major stimulatory input to the GnRH neuronal network that is responsible for triggering the preovulatory LH surge. Noradrenaline (NA) is one of the main modulators of GnRH release, and NA fibers are found in close apposition to kisspeptin neurons in the RP3V. Our objective was to interrogate the role of NA signaling in the kisspeptin control of GnRH secretion during the estradiol induced LH surge in ovariectomized rats, using prazosin, an α1-adrenergic receptor antagonist. In control rats, the estradiol-induced LH surge at 17 hours was associated with a significant increase in GnRH and kisspeptin content in the median eminence with the increase in kisspeptin preceding that of GnRH and LH. Prazosin, administered 5 and 3 hours prior to the predicted time of the LH surge truncated the LH surge and abolished the rise in GnRH and kisspeptin in the median eminence. In the preoptic area, prazosin blocked the increases in Kiss1 gene expression and kisspeptin content in association with a disruption in the expression of the clock genes, Per1 and Bmal1. Together these findings demonstrate for the first time that NA modulates kisspeptin synthesis in the RP3V through the activation of α1-adrenergic receptors prior to the initiation of the LH surge and indicate a potential role of α1-adrenergic signaling in the circadian-controlled pathway timing of the preovulatory LH surge.

  14. Storm surge and wave simulations in the Gulf of Mexico using a consistent drag relation for atmospheric and storm surge models

    Directory of Open Access Journals (Sweden)

    D. Vatvani

    2012-07-01

    Full Text Available To simulate winds and water levels, numerical weather prediction (NWP and storm surge models generally use the traditional bulk relation for wind stress, which is characterized by a wind drag coefficient. A still commonly used drag coefficient in those models, some of them were developed in the past, is based on a relation, according to which the magnitude of the coefficient is either constant or increases monotonically with increasing surface wind speed (Bender, 2007; Kim et al., 2008; Kohno and Higaki, 2006. The NWP and surge models are often tuned independently from each other in order to obtain good results. Observations have indicated that the magnitude of the drag coefficient levels off at a wind speed of about 30 m s−1, and then decreases with further increase of the wind speed. Above a wind speed of approximately 30 m s−1, the stress above the air-sea interface starts to saturate. To represent the reducing and levelling off of the drag coefficient, the original Charnock drag formulation has been extended with a correction term.

    In line with the above, the Delft3D storm surge model is tested using both Charnock's and improved Makin's wind drag parameterization to evaluate the improvements on the storm surge model results, with and without inclusion of the wave effects. The effect of waves on storm surge is included by simultaneously simulating waves with the SWAN model on identical model grids in a coupled mode. However, the results presented here will focus on the storm surge results that include the wave effects.

    The runs were carried out in the Gulf of Mexico for Katrina and Ivan hurricane events. The storm surge model was initially forced with H*wind data (Powell et al., 2010 to test the effect of the Makin's wind drag parameterization on the storm surge model separately. The computed wind, water levels and waves are subsequently compared with observation data. Based on the good

  15. Development of wave and surge atlas for the design and protection of coastal bridges in South Louisiana : [research project capsule].

    Science.gov (United States)

    2015-03-01

    The recently completed Louisiana Department of Transportation and Development : (DOTD) Storm Surge and Wave Atlas contains signi cant hydraulic information that will : be useful in analyzing storm surge and wave forces on existing and new coastal ...

  16. Surge snubber design for high power-density DC-DC converters in HVDC power distribution systems

    OpenAIRE

    Domoto, Kazuhide; Ninomiya, Tamotsu; Ishizuka, Yoichi; Simanjorang, Rejeki; Yamaguchi, Hiroshi; Abe, Seiya; Kaga, Masato

    2012-01-01

    In an isolated DC-DC converter utilized in the HVDC power distribution system, a large surge voltage occurs across the secondary-side diodes due to the transformer's leakage inductance, and then the diodes with a large withstand voltage are required. However, those diodes cause a lot of power loss. In this paper, a simple surge snubber with prominent surge suppression capability is examined, and the surge-voltage evaluation through the analysis using the high-frequency equivalent circuits, wh...

  17. Quantification of Sediment Transport During Glacier Surges and its Impact on Landform Architecture

    Science.gov (United States)

    Kjaer, K. H.; Schomacker, A.; Korsgaard, N. J.; Benediktsson, I. O.

    2008-12-01

    Multi-temporal DEMs (Digital Elevation Models) of glaciers and ice streams have successfully been used for extraction of changes in ice volume over time. In this study, we analysed DEMs of the Brúarjökull glacier forefield (Iceland) for 1945, prior to the last surge in 1964, and for 2003 in order to assess the effect of the surge on the sediment architecture in the forefield. The pre- and post-surge DEMs allow direct quantification of the sediment volumes that were re-distributed in the forefield by the surging ice mass in 1964. The surge-type glacier Brúarjökull has experienced six surges during the last four centuries; these are the largest surges known to have occurred in Iceland. During the most recent surge in 1963-64, the glacier advanced 8 km over a period of c. 3 months with a maximum ice flow velocity of 5 m/hr, and 700 km3 of ice were moved downglacier. The continued recession of Brúarjökull since the 1963-64 surge reveals a young landscape consisting of widely spaced and elongated bedrock hills interspaced with shallow sedimentary basins. The majority of the forefield is covered with a basal till sheet or glaciofluvial outwash fans. Mapping of the sediment thickness in the glacier forefield shows higher accumulation along ice marginal positions related to wedge formation during extremely rapid ice flow. Fast flow was sustained by overpressurized water causing sediment-bedrock decoupling beneath a thick sediment sequence that was coupled to the glacier. Elevation differences between the terrain surface in 1945 and 2003 confirm this scenario as huge quantities of sediment was eroded, deformed and transported during the last surge event. On the scale of individual landforms, it appears for a drumlin surface that is has been lowered 20 m from 1945-2003. Dead-ice melting can explain roughly 8 m of this lowering. Thus, the drumlin must have experienced 12 m of subglacial erosion during the 1964 surge. The imprint of at least four landform generations is

  18. Storm surges in the White and Barents Seas: formation, statistics, analysis

    Science.gov (United States)

    Korablina, Anastasia; Arkhipkin, Victor

    2017-04-01

    Arctic seas storm surges investigation are high priority in Russia due to the active development of offshore oil and gas, construction of facilities in the coastal zone, as well as for the navigation safety. It is important to study the surges variability, to predict this phenomena and subsequent economic losses, thus including such information into the Russian Arctic Development Program 2020. White and Barents Seas storm surges are caused mainly by deep cyclones of two types: "diving" from the north (88% of all cyclones) and Atlantic from the west. The surge height was defined as the excess of the level that was obtained as the difference between the observed level and subtracting tide level and low-frequency level. The period of low-frequency level oscillation was determined by spectral analysis of the in-situ data. ADCIRC model is used for calculating the storm surge height. We did the calculations on unstructured grid with variable step from 50 to 5000 m. The ADCIRC model was based on the data on wind field, the sea level pressure, the concentration of ice reanalysis CFSR (1979-2010) in increments 0.3°, CFSv2 (2011-2015) in increments 0.2°. On the boundary conditions harmonic constants from Finite Element Solution tide model 2004 (FES2004) in increments 1/8° were set. The following stations on the coast Varandey, Pechora Bay, Chosha Bay, Severodvinsk, Onega, Solovki and other were selected for the storm surges statistical analysis in the period 1979-2015. The number of storm surges (> 0.3 m) long-term variability was obtained, the number of surges at a height (m) range (0.3-0.6, 0.6-0.9, 0.9-1.2, >1.2) was estimated. It shows that 1980 and 1998 are the years with the fewest number storms. For example, the largest number of storm surge (53) was observed in 1995 in Varandey. The height of the surge, possible only once in 100 years, is counted. This maximum height (m) of the surge was noted in Varandey (4.1), Chosha Bay (3.4), Barents Sea, Onega Bay (2

  19. Stability Analysis of a Run-of-River Diversion Hydropower Plant with Surge Tank and Spillway in the Head Pond

    Directory of Open Access Journals (Sweden)

    José Ignacio Sarasúa

    2014-01-01

    Full Text Available Run-of-river hydropower plants usually lack significant storage capacity; therefore, the more adequate control strategy would consist of keeping a constant water level at the intake pond in order to harness the maximum amount of energy from the river flow or to reduce the surface flooded in the head pond. In this paper, a standard PI control system of a run-of-river diversion hydropower plant with surge tank and a spillway in the head pond that evacuates part of the river flow plant is studied. A stability analysis based on the Routh-Hurwitz criterion is carried out and a practical criterion for tuning the gains of the PI controller is proposed. Conclusions about the head pond and surge tank areas are drawn from the stability analysis. Finally, this criterion is applied to a real hydropower plant in design state; the importance of considering the spillway dimensions and turbine characteristic curves for adequate tuning of the controller gains is highlighted.

  20. Subglacial bedforms and conditions associated with the 1991 surge of Skeidarárjökull, Iceland

    NARCIS (Netherlands)

    Waller, R.I.; Dijk, T. van; Knudson, O.

    2008-01-01

    Much previous research at surge-type glaciers has sought to identify features diagnostic of surge-type behaviour. However, in comparatively little work have subglacial landform-sediment characteristics been used to reconstruct changing basal processes and conditions during surge events. Subglacial

  1. Coastal geohazards and storm surges: The Indian context

    Science.gov (United States)

    Murty, K. S.

    2009-04-01

    that hit the Orisaa coast killed more than 15,000 people and rendered more than a million people homeless. Shelters have been built in the cyclone-prone areas on the coast and the communication systems have been modernised. After the 2004 tsunami, a storm surge and tsunami warning system as been set up that operates from Hyderabad. This involved strengthening the exisiting seismological network to indicate near real time occurence of a tsunamigenic earthquake. The surge during the 1977 cyclone was one of the most devastating surges in the recent past along the east coast of India. The Indian Meteorological Department instralled cyclone warning centres on the east coast. Detection radars have been installed that can track cyclones within a range of 400 kms from the coast. Beyond this range, satellite imageries are used. The OCEAN SAT-1 AND 2 serve this purpose. Climate change is expected to cause rise of sea levels and countries with vast coastlines have necessarily to take appropriate steps to face the challenge in future and India is among them.

  2. A Pilot Study of Pedestrians with Visual Impairments Detecting Traffic Gaps and Surges Containing Hybrid Vehicles

    Science.gov (United States)

    Emerson, Robert Wall; Naghshineh, Koorosh; Hapeman, Julie; Wiener, William

    2010-01-01

    The increasing number of hybrid and quiet internal combustion engine vehicles may impact the travel abilities of pedestrians who are blind. Pedestrians who rely on auditory cues for structuring their travel may face challenges in making crossing decisions in the presence of quiet vehicles. This article describes results of initial studies looking at the crossing decisions of pedestrians who are blind at an uncontrolled crossing (no traffic control) and a light controlled intersection. The presence of hybrid vehicles was a factor in each situation. At the uncontrolled crossing, Toyota hybrids were most difficult to detect but crossing decisions were made more often in small gaps ended by a Honda hybrid. These effects were seen only at speed under 20 mph. At the light controlled intersection, parallel surges of traffic were most difficult to detect when made up only of a Ford Escape hybrid. Results suggest that more controlled studies of vehicle characteristics impacting crossing decisions of pedestrians who are blind are warranted. PMID:21379367

  3. Developmental programming: Prenatal BPA treatment disrupts timing of LH surge and ovarian follicular wave dynamics in adult sheep

    Energy Technology Data Exchange (ETDEWEB)

    Veiga-Lopez, A.; Beckett, E.M.; Abi Salloum, B. [Department of Pediatrics, University of Michigan, Ann Arbor, MI (United States); Ye, W. [Department of Biostatistics, University of Michigan, Ann Arbor, MI (United States); Padmanabhan, V., E-mail: vasantha@umich.edu [Department of Pediatrics, University of Michigan, Ann Arbor, MI (United States); The Reproductive Sciences Program, University of Michigan, Ann Arbor, MI (United States)

    2014-09-01

    Developmental exposure to BPA adversely affects reproductive function. In sheep, prenatal BPA treatment induces reproductive neuroendocrine defects, manifested as LH excess and dampened LH surge and perturbs early ovarian gene expression. In this study we hypothesized that prenatal BPA treatment will also disrupt ovarian follicular dynamics. Pregnant sheep were treated from days 30 to 90 of gestation with 3 different BPA doses (0.05, 0.5, or 5 mg/kg BW/day). All female offspring were estrus synchronized and transrectal ultrasonography was performed daily for 22 days to monitor ovarian follicular and corpora lutea dynamics. Blood samples were collected to assess preovulatory hormonal changes and luteal progesterone dynamics. Statistical analysis revealed that the time interval between the estradiol rise and the preovulatory LH surge was shortened in the BPA-treated females. None of the three BPA doses had an effect on corpora lutea, progestogenic cycles, and mean number or duration of ovulatory and non-ovulatory follicles. However, differences in follicular count trajectories were evident in all three follicular size classes (2–3 mm, 4–5 mm, and ≥ 6 mm) of prenatal BPA-treated animals compared to controls. Number of follicular waves tended also to be more variable in the prenatal BPA-treated groups ranging from 2 to 5 follicular waves per cycle, while this was restricted to 3 to 4 waves in control females. These changes in ovarian follicular dynamics coupled with defects in time interval between estradiol rise and preovulatory LH release are likely to lead to subfertility in prenatal BPA-treated females. - Highlights: • Prenatal BPA shortens interval between estradiol rise and preovulatory LH surge. • Prenatal BPA affects follicular count trajectory and follicular wave occurrence. • Prenatal BPA does not affect ovulatory rate and progesterone dynamics.

  4. Dynamic Modeling of Surface Runoff and Storm Surge during Hurricane and Tropical Storm Events

    Directory of Open Access Journals (Sweden)

    Walter F. Silva-Araya

    2018-02-01

    Full Text Available Hurricane events combine ocean storm surge penetration with inland runoff flooding. This article presents a new methodology to determine coastal flood levels caused by the combination of storm surge and surface runoff. The proposed approach couples the Simulating Waves Nearshore model and the Advanced Circulation (ADCIRC model with the Gridded Surface Subsurface Hydrologic Analysis (GSSHA two-dimensional hydrologic model. Radar precipitation data in a 2D hydrologic model with a circulation model allows simulation of time and spatially varied conditions. The method was applied to study flooding scenarios occurring during the passage of Hurricane Georges (1998 on the east coast of Puerto Rico. The combination of storm surge and surface runoff produced a critical scenario, in terms of flood depth, at this location. The paper describes the data collection process, circulation and hydrologic models, their assemblage and simulation scenarios. Results show that peak flow from inland runoff and peak flow due to storm surge did not coincide in the coastal zone; however, the interaction of both discharges causes an aggravated hazardous condition by increasing flood levels beyond those obtained with storm surge penetration only. Linking of storm surge and hydrologic models are necessary when storm surge conditions occur simultaneously with high precipitation over steep and small coastal watersheds.

  5. Reflection and dampening of pressure waves in marine terminal pressure surge analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kossatz, Helmut [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil); Ladeia, Renata C. da Cunha [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica. Nucleo de Simulacao Termohidraulica de Dutos (SIMDUT)

    2005-07-01

    In the analysis of potential surge pressure hazards in marine terminals, the piping system connecting the terminal's tank farm to the oil tanker is commonly composed of a main pipeline ending in reduced diameter devices of relatively short length such as loading arms or cargo hoses, and pressure surges may be generated due sudden closure of the oil tanker's emergency shut down valves, or from closure of valves in quick breakaway couplings. Since velocities in these smaller diameter sections are much higher than in the main pipeline, local pressure peaks may occur which are greater than the surge pressure generated due to flow stoppage in the larger diameter pipe. These local pressure pulses are rapidly damped out due to reflection at the connection with the larger diameter pipeline and are simultaneously transmitted and superposed on the pressure surge generated in the main pipeline. Cargo hoses are more elastic with much lower acoustic speed than in steel pipe, and local pressure surges are therefore smaller than in an equivalent section of steel pipeline. Nevertheless local surge pressures are still capable of being greater than in the main steel pipeline due to higher initial flow velocities. This work analyses these effects and points out the care to be taken in pressure surge simulation in order to obtain reliable results. (author)

  6. Predicting Typhoon Induced Storm Surges Using the Operational Ocean Forecast System

    Directory of Open Access Journals (Sweden)

    Sung Hyup You

    2010-01-01

    Full Text Available This study was performed to compare storm surges simulated by the operational storm surges/tide forecast system (STORM : Storm surges/Tide Operational Model of the Korea Meteorological Administration (KMA with observations from 30 coastal tidal stations during nine typhoons that occurred between 2005 and 2007. The results (bias showed that for cases of overestimation (or underestimation, storm surges tended to be overestimated (as well as underestimated at all coastal stations. The maximum positive bias was approximately 6.92 cm for Typhoon Ewiniar (2006, while the maximum negative bias was approximately -12.06 cm for Typhoon Khanun (2005. The maximum and minimum root mean square errors (RMSEs were 14.61 and 6.78 cm, which occurred for Typhoons Khanun (2005 and Usagi (2007, respectively. For all nine typhoons, total averaged RMSE was approximately 10.2 cm. Large differences between modeled and observed storm surges occurred in two cases. In the first, a very weak typhoon, such as Typhoon Khanun (2005, caused low storm surges. In the other, exemplified by Typhoon Nari (2007, there were errors in the predicted typhoon strength used as input data for the storm surge model.

  7. The effectiveness of earlier oocyte retrieval in the case of a premature luteinizing hormone surge on hCG day in in vitro fertilization-embryo transfer cycles.

    Science.gov (United States)

    Choi, Min Hye; Cha, Sun Hwa; Park, Chan Woo; Kim, Jin Young; Yang, Kwang Moon; Song, In Ok; Koong, Mi Kyoung; Kang, Inn Soo; Kim, Hye Ok

    2013-06-01

    To evaluate the efficacy of earlier oocyte retrieval in IVF patients with a premature LH surge on hCG day. One hundred forty IVF patients (164 cycles) with premature LH surge on hCG day were included, retrospectively. We divided them into 2 study groups: LH surge with timed ovum pick-up (OPU) 36 hours after hCG injection (group B, 129 premature cycles), and LH surge with earlier OPU within 36 hours after hCG injection (group C, 35 cycles). Control groups were tubal factor infertility without premature LH surge (group A, 143 cycles). The mean age (year) was statistically higher in group C than in groups A or B (38.2±5.4 vs. 36.2±4.2 vs. 36.8±4.9, respectively; p=0.012). The serum LH levels (mIU/mL) on hCG day were significantly higher in group B and C than in group A (22.7±14.9 vs. 30.3±15.9 vs. 3.2±2.9, respectively; p>0.001). Among groups A, B, and C, 4.9%, 31.7%, and 51.4% of the cycles, respectively, had no oocytes, and the overall rates of cycle cancellation (OPU cancellation, no oocyte, or no embryos transferrable) were 15.4%, 65.9%, and 74.3%, respectively. The fertilization rate (%) was significantly higher in group B than in group C (73.2±38.9 vs. 47.8±42.9, p=0.024). The clinical pregnancy rate was significantly higher in group C than in groups A and B (44.4% vs. 27.3% vs. 9.1%, respectively, p=0.021). However, the miscarriage rate was also higher in group C than in group B (22% vs. 0%, respectively, p=0.026). Earlier OPU may not be effective in reducing the risk of cycle cancellation in patients with premature LH surge on hCG day. A larger scale study will be required to reveal the effectiveness of earlier ovum retrieval with premature LH surge.

  8. A global record of large storm surges and loss of life

    Science.gov (United States)

    Bouwer, Laurens; Jonkman, Sebastiaan

    2017-04-01

    Storm surges can cause very high numbers of loss of life (fatalities) in single events, and these events are expected to increase due to sea-level rise and increasing population in coastal zones. However, compared to fatalities from fresh water flooding, for storm surges these fatality numbers are not consistently recorded, and often neglected in scientific assessments. In order to assess the impacts of major coastal storm surge events at the global level, we have developed a record of these events and associated loss of life. Information was compiled from the EM-DAT database for the period 1900-2013, using the two key categories of "Tropical cyclone" and "Storm surge/coastal flood", complemented with other databases and sources of information, and records of observed surge levels. We find that globally, each year on average about 8,500 people are killed and 1.3 million people are affected by storm surges. The occurrence of very substantial loss of life (>10,000 persons) from single events has decreased over time, which is in contrast with the slight increasing trends in fatalities observed for fresh water flooding. Also, there is a consistent and strong decrease in event mortality, which is the fraction of the people exposed to surges that lose their life, for all global regions, except South-East Asia. Thus, reduction in vulnerability to loss of life over time plays a significant role in storm surge impacts. We also find that for the same coastal surge water level, mortality appears to have decreased over time, showing the robustness of this finding. This quantified decline can be attributed to risk reduction efforts over the last decades, including improved forecasting, early warning and evacuation, but also improved coastal protection. These results have important implications for assessment studies on current and projected future coastal flood risk, as historical mortality fractions may not be valid to assess impacts from future events.

  9. Slab entrainment and surge dynamics of the 2015 Valleé de la Sionne avalanches

    Science.gov (United States)

    Köhler, Anselm; McElwaine, Jim; Sovilla, Betty

    2016-04-01

    On 3 February 2015 five avalanches were artificially released at the Valleé de la Sionne test site in the west of Switzerland. The dense parts of the avalanches were tracked by the GEODAR Mark 2 radar system at 111 Hz framerate with 0.75 m down slope resolution. The data show that these avalanche contain several internal surges and that the avalanche front is repeatedly overtaken by some of these surges. We show that these surges exist on different scale. While the major surges originates from secondary triggered slab releases and occur all over the avalanche. The minor surges are only found in the energetic part of a well developed powder snow avalanche. The mass of the major surges can be as huge as the initial released mass, this has a dramatic effect on the mass distribution inside the avalanche and effects the front velocity and run out. Furthermore, the secondary released snow slabs are an important entrainment mechanism and up to 50 percent of the mass entered the avalanche via slab entrainment. We analyse the dynamics of the leading edge and the minor surges in more detail using a simple one dimensional model with frictional resistance and quadratic velocity dependent drag. These models fit the data well for the start and middle of avalanche but cannot capture the slowing and overtaking of the minor surge. We find much higher friction coefficients to describe the surging. We propose that this data can only be explained by changes in the snow surface. These effects are not included in current models yet, but the data presented here will enable the development and verification of such models.

  10. THE KINEMATICS AND PLASMA PROPERTIES OF A SOLAR SURGE TRIGGERED BY CHROMOSPHERIC ACTIVITY IN AR11271

    Energy Technology Data Exchange (ETDEWEB)

    Kayshap, P.; Srivastava, Abhishek K. [Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital 263 129 (India); Murawski, K., E-mail: kmur@kft.umcs.lublin.pl [Group of Astrophysics, UMCS, ul. Radziszewskiego 10, 20-031 Lublin (Poland)

    2013-01-20

    We observe a solar surge in NOAA AR11271 using the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly 304 A image data on 2011 August 25. The surge rises vertically from its origin up to a height of Almost-Equal-To 65 Mm with a terminal velocity of Almost-Equal-To 100 km s{sup -1}, and thereafter falls and fades gradually. The total lifetime of the surge was Almost-Equal-To 20 minutes. We also measure the temperature and density distribution of the observed surge during its maximum rise and find an average temperature and a density of 2.0 MK and 4.1 Multiplication-Sign 10{sup 9} cm{sup -3}, respectively. The temperature map shows the expansion and mixing of cool plasma lagging behind the hot coronal plasma along the surge. Because SDO/HMI temporal image data do not show any detectable evidence of significant photospheric magnetic field cancellation for the formation of the observed surge, we infer that it is probably driven by magnetic-reconnection-generated thermal energy in the lower chromosphere. The radiance (and thus the mass density) oscillations near the base of the surge are also evident, which may be the most likely signature of its formation by a reconnection-generated pulse. In support of the present observational baseline of the triggering of the surge due to chromospheric heating, we devise a numerical model with conceivable implementation of the VAL-C atmosphere and a thermal pulse as an initial trigger. We find that the pulse steepens into a slow shock at higher altitudes which triggers plasma perturbations exhibiting the observed features of the surge, e.g., terminal velocity, height, width, lifetime, and heated fine structures near its base.

  11. α-Estrogen and Progesterone Receptors Modulate Kisspeptin Effects on Prolactin: Role in Estradiol-Induced Prolactin Surge in Female Rats.

    Science.gov (United States)

    Aquino, Nayara S S; Araujo-Lopes, Roberta; Henriques, Patricia C; Lopes, Felipe E F; Gusmao, Daniela O; Coimbra, Candido C; Franci, Celso R; Reis, Adelina M; Szawka, Raphael E

    2017-06-01

    Kisspeptin (Kp) regulates prolactin (PRL) in an estradiol-dependent manner. We investigated the interaction between ovarian steroid receptors and Kp in the control of PRL secretion. Intracerebroventricular injections of Kp-10 or Kp-234 were performed in ovariectomized (OVX) rats under different hormonal treatments. Kp-10 increased PRL release and decreased 3,4-dihydroxyphenylacetic acid levels in the median eminence (ME) of OVX rats treated with estradiol (OVX+E), which was prevented by tamoxifen. Whereas these effects of Kp-10 were absent in OVX rats, they were replicated in OVX rats treated with selective agonist of estrogen receptor (ER)α, propylpyrazole triol, but not of ERβ, diarylpropionitrile. Furthermore, the Kp-10-induced increase in PRL was two times higher in OVX+E rats also treated with progesterone (OVX+EP), which was associated with a reduced expression of both tyrosine hydroxylase (TH) and Ser40-phosphorylated TH in the ME. Kp-10 also reduced dopamine levels in the ME of OVX+EP rats, an effect blocked by the progesterone receptor (PR) antagonist RU486. We also determined the effect of Kp antagonism with Kp-234 on the estradiol-induced surges of PRL and luteinizing hormone (LH), using tail-tip blood sampling combined with ultrasensitive enzyme-linked immunosorbent assay. Kp-234 impaired the early phase of the PRL surge and prevented the LH surge in OVX+E rats. Thus, we provide evidence that Kp stimulation of PRL release requires ERα and is potentiated by progesterone via PR activation. Moreover, alongside its essential role in the LH surge, Kp seems to play a role in the peak phase of the estradiol-induced PRL surge. Copyright © 2017 Endocrine Society.

  12. The Danger of Deja Vu: Why the Iraq Surge is Not a Lesson for Afghanistan

    Science.gov (United States)

    2010-01-01

    JAN 2010 2. REPORT TYPE 3. DATES COVERED 00-12-2009 to 00-01-2010 4. TITLE AND SUBTITLE The danger of deja vu . Why the Iraq surge is not a lesson...of five brigade combat teams — eerily mim- icked the surge number for Iraq. And there was more déjà vu when our senior civilian and military leaders...Department. PERSPECTIVES The danger of déjà vu Why the Iraq surge is not a lesson for Afghanistan BY COL. CHARLES D. ALLEN (RET.) The thing we take hold of

  13. Magnitude of Morning Surge in Blood Pressure Is Associated with Sympathetic but Not Cardiac Baroreflex Sensitivity.

    Science.gov (United States)

    Johnson, Aaron W; Hissen, Sarah L; Macefield, Vaughan G; Brown, Rachael; Taylor, Chloe E

    2016-01-01

    The ability of the arterial baroreflex to regulate blood pressure may influence the magnitude of the morning surge in blood pressure (MSBP). The aim was to investigate the relationships between sympathetic and cardiac baroreflex sensitivity (BRS) and the morning surge. Twenty-four hour ambulatory blood pressure was recorded in 14 young individuals. The morning surge was defined via the pre-awakening method, which is calculated as the difference between mean blood pressure values 2 h before and 2 h after rising from sleep. The mean systolic morning surge, diastolic morning surge, and morning surge in mean arterial pressures were 15 ± 2, 13 ± 1, and 11 ± 1 mmHg, respectively. During the laboratory protocol, continuous measurements of blood pressure, heart rate, and muscle sympathetic nerve activity (MSNA) were made over a 10-min period of rest. Sympathetic BRS was quantified by plotting MSNA burst incidence against diastolic pressure (sympathetic BRSinc), and by plotting total MSNA against diastolic pressure (sympathetic BRStotal). Cardiac BRS was quantified using the sequence method. The mean values for sympathetic BRSinc, sympathetic BRStotal and cardiac BRS were -1.26 ± 0.26 bursts/100 hb/mmHg, -1.60 ± 0.37 AU/beat/mmHg, and 13.1 ± 1.5 ms/mmHg respectively. Significant relationships were identified between sympathetic BRSinc and the diastolic morning surge (r = 0.62, p = 0.02) and the morning surge in mean arterial pressure (r = 0.57, p = 0.03). Low sympathetic BRS was associated with a larger morning surge in mean arterial and diastolic blood pressure. Trends for relationships were identified between sympathetic BRStotal and the diastolic morning surge (r = 0.52, p = 0.066) and the morning surge in mean arterial pressure (r = 0.48, p = 0.095) but these did not reach significance. There were no significant relationships between cardiac BRS and the morning surge. These findings indicate that the ability of the baroreflex to buffer increases in blood pressure

  14. The resistance change of the power diodes under the influence of the surge current impulses

    Directory of Open Access Journals (Sweden)

    Tishchenko I. Yu.

    2007-12-01

    Full Text Available The paper presents the investigations of causes of failure of the crystals of semiconductor power diodes while surge current pulses pass through them. It is shown that when currents values are lower than the surge current, the impact resistance and reliability of the diode do not change. At surge current, the resistance of the diode increases with each repeated pulse. After several pulses have passed, the diode fails, because its forward resistance increases 3 times, and the temperature greatly exceeds the acceptable level. The authors explain the observed effects.

  15. Magnetic field changes associated with a sub-flare and surge

    Science.gov (United States)

    Hagyard, M. J.; West, E. A.; Smith, J. E.

    1993-01-01

    A sub-flare and surge were observed on June 13, 1990, with the Marshall Space Flight Center vector magnetograph and coaligned H-alpha telescope. This activity occurred at the site of a parasitic polarity near a large, mature sunspot. Analysis of the vector magnetic field showed that while flux emergence and other field changes occurred sporadically throughout a period of four days, the sub-flare and surge only took place after an increase in magnetic shear in the field of the parasitic polarity. This event also provided an example of relaxation of magnetic shear following the flare and surging.

  16. Smart Ultrasound Remote Guidance Experiment (SURGE) Preliminary Findings

    Science.gov (United States)

    Hurst, Victor; Dulchavsky, Scott; Garcia, Kathleen; Sargsyan, Ashot; Ebert, Doug

    2009-01-01

    To date, diagnostic quality ultrasound images were obtained aboard the International Space Station (ISS) using the ultrasound of the Human Research Facility (HRF) rack in the Laboratory module. Through the Advanced Diagnostic Ultrasound in Microgravity (ADUM) and the Braslet-M Occlusion Cuffs (BRASLET SDTO) studies, non-expert ultrasound operators aboard the ISS have performed cardiac, thoracic, abdominal, vascular, ocular, and musculoskeletal ultrasound assessments using remote guidance from ground-based ultrasound experts. With exploration class missions to the lunar and Martian surfaces on the horizon, crew medical officers will necessarily need to operate with greater autonomy given communication delays (round trip times of up to 5 seconds for the Moon and 90 minutes for Mars) and longer periods of communication blackouts (due to orbital constraints of communication assets). The SURGE project explored the feasibility and training requirements of having non-expert ultrasound operators perform autonomous ultrasound assessments in a simulated exploration mission outpost. The project aimed to identify experience, training, and human factors requirements for crew medical officers to perform autonomous ultrasonography. All of these aims pertained to the following risks from the NASA Bioastronautics Road Map: 1) Risk 18: Major Illness and Trauna; 2) Risk 20) Ambulatory Care; 3) Risk 22: Medical Informatics, Technologies, and Support Systems; and 4) Risk 23: Medical Skill Training and Maintenance.

  17. Nivmar: a storm surge forecasting system for Spanish waters

    Directory of Open Access Journals (Sweden)

    Enrique Álvarez Fanjul

    2001-07-01

    Full Text Available In this paper, a storm surge prediction system for the Spanish Waters is presented. The system, named Nivmar, is based on the ocean circulation Hamsom model and on the harmonical prediction of tides computed from data measured by the tide gauge network Redmar, managed by Puertos del Estado. Nivmar is executed twice a day, running Hamsom forced by meteorological fields derived from the INM (Instituto Nacional de Meteorología operational application of Hirlam atmospheric model. Data from Redmar tide gauges is used to to forecast the tidal elevations, to validate the system and to perform data assimilation, correcting systematic errors in the mean sea level due to physicals processes that are not included in the ocean model (i. e. steric height. The forecast horizon is 48 hours. In order to validate the system with measured data from Redmar a very stormy 5 months period was selected. Results from this test (November 95 to March 96 are presented. Data from this experiment shown that Nivmar is able to correctly predict sea level in the region. A simple data assimilation scheme for sea level is described and results from its application are studied. Finally, special focus is made in future plans and potential developments and applications of the system.

  18. Centrifugal and axial compressor control

    CERN Document Server

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  19. Mapping dependence between extreme rainfall and storm surge across the Australian coastline using ROMS

    Science.gov (United States)

    Wu, Wenyan; Westra, Seth; Lenord, Michael; McInnes, Kathleen

    2017-04-01

    Storm surge caused by a combination of wind action and low pressure acting on the ocean's surface is a significant contributor to flooding in coastal and estuarine regions. When coincided with other flood-producing mechanisms such as extreme rainfall, the consequences can be devastating. Therefore it is important to understand the interaction between extreme storm surge and extreme rainfall. Previously, the dependence between extreme storm surge and extreme rainfall in Australia has been investigated using observed data from 49 tide gauges along the Australian coastline and statistically significant dependence has been observed for the majority of the locations (Zheng et al. 2013). However, in order to assess the flood risk due to coincident extreme surge and rainfall along coastal regions, more detailed mapping (e.g. including locations where there is no tide gauge) of the dependence between the two flood producing factors is required. There is also a need to quantify changes in dependence under climate change in order to understand future flood risk. Therefore, it is important to be able to quantify the dependence between extreme storm surge and extreme rainfall using modelled data. In this study, we investigated the dependence between extreme storm surge and extreme rainfall using modelled storm surge data from the Regional Ocean Modeling System (ROMS) (Shchepetkin and McWilliams 2005). Storm surge data from 551 locations along the Australian coastline (at 30 km intervals) between the 1st of January 1981 and the 7th of May 2013 were used. These locations were paired with daily rainfall from gauges within a 30 km radius. A bivariate logistic threshold-excess model was employed to quantify the dependence between extreme daily storm surge and extreme daily rainfall. The results were compared with dependence values calculated using observed storm surge at 79 tide gauges around Australia. Promising results were obtained. The dependence calculated using modelled storm

  20. Development of a nearshore oscillating surge wave energy converter with variable geometry

    Energy Technology Data Exchange (ETDEWEB)

    Tom, N. M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lawson, M. J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Yu, Y. H. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wright, A. D. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-10-01

    This paper presents an analysis of a novel wave energy converter concept that combines an oscillating surge wave energy converter (OSWEC) with control surfaces. The control surfaces allow for a variable device geometry that enables the hydrodynamic properties to be adapted with respect to structural loading, absorption range and power-take-off capability. The device geometry is adjusted on a sea state-to-sea state time scale and combined with wave-to-wave manipulation of the power take-off (PTO) to provide greater control over the capture efficiency, capacity factor, and design loads. This work begins with a sensitivity study of the hydrodynamic coefficients with respect to device width, support structure thickness, and geometry. A linear frequency domain analysis is used to evaluate device performance in terms of absorbed power, foundation loads, and PTO torque. Previous OSWEC studies included nonlinear hydrodynamics, in response a nonlinear model that includes a quadratic viscous damping torque that was linearized via the Lorentz linearization. Inclusion of the quadratic viscous torque led to construction of an optimization problem that incorporated motion and PTO constraints. Results from this study found that, when transitioning from moderate-to-large sea states the novel OSWEC was capable of reducing structural loads while providing a near constant power output.

  1. Global Positioning System surveys of storm-surge sensors deployed during Hurricane Ike, Seadrift, Texas, to Lake Charles, Louisiana, 2008

    Science.gov (United States)

    Payne, Jason; Woodward, Brenda K.; Storm, John B.

    2009-01-01

    The U.S. Geological Survey installed a network of pressure sensors at 65 sites along the Gulf Coast from Seadrift, Texas, northeast to Lake Charles, Louisiana, to record the timing, areal extent, and magnitude of inland storm surge and coastal flooding caused by Hurricane Ike in September 2008. A Global Positioning System was used to obtain elevations of reference marks near each sensor. A combination of real-time kinematic (RTK) and static Global Positioning System surveys were done to obtain elevations of reference marks. Leveling relative to reference marks was done to obtain elevations of sensor orifices above the reference marks. This report summarizes the Global Positioning System data collected and processed to obtain reference mark and storm-sensor-orifice elevations for 59 storm-surge sensors recovered from the original 65 installed as a necessary prelude to computation of storm-surge elevations. National Geodetic Survey benchmarks were used for RTK surveying. Where National Geodetic Survey benchmarks were not within 12 kilometers of a sensor site, static surveying was done. Additional control points for static surveying were in the form of newly established benchmarks or reestablished existing benchmarks. RTK surveying was used to obtain positions and elevations of reference marks for 29 sensor sites. Static surveying was used to obtain positions and elevations of reference marks for 34 sensor sites; four sites were surveyed using both methods. Multiple quality checks on the RTK-survey and static-survey data were applied. The results of all quality checks indicate that the desired elevation accuracy for the surveys of this report, less than 0.1-meter error, was achieved.

  2. Chitosan-nanoconjugated hormone nanoparticles for sustained surge of gonadotropins and enhanced reproductive output in female fish.

    Directory of Open Access Journals (Sweden)

    Mohd Ashraf Rather

    Full Text Available A controlled release delivery system helps to overcome the problem of short life of the leutinizing hormone releasing hormone (LHRH in blood and avoids use of multiple injections to enhance reproductive efficacy. Chitosan- and chitosan-gold nanoconjugates of salmon LHRH of desired size, dispersity and zeta potential were synthesized and evaluated at half the dose rate against full dose of bare LHRH for their reproductive efficacy in the female fish, Cyprinus carpio. Whereas injections of both the nanoconjugates induced controlled and sustained surge of the hormones with peak (P<0.01 at 24 hrs, surge due to bare LHRH reached its peak at 7 hrs and either remained at plateau or sharply declined thereafter. While the percentage of relative total eggs produced by fish were 130 and 67 per cent higher, that of fertilised eggs were 171 and 88 per cent higher on chitosan- and chitosan-gold nanoconjugates than bare LHRH. Chitosan nanoconjugates had a 13 per cent higher and chitosan gold preparation had a 9 per cent higher fertilization rate than bare LHRH. Histology of the ovaries also attested the pronounced effect of nanoparticles on reproductive output. This is the first report on use of chitosan-conjugated nanodelivery of gonadotropic hormone in fish.

  3. Simulation of Wind Speed in the Ventilation Tunnel for Surge Tanks in Transient Processes

    National Research Council Canada - National Science Library

    Yang, Jiandong; Wang, Huang; Guo, Wencheng; Yang, Weijia; Zeng, Wei

    2016-01-01

    .... To obtain the wind speed in a ventilation tunnel for a surge tank during transient processes, this article adopts the one-dimensional numerical simulation method and establishes a mathematical model...

  4. Europa's opposition surge in the near-infrared: interpreting disk-integrated observations by Cassini VIMS

    Science.gov (United States)

    Simonelli, Damon P.; Buratti, Bonnie J.

    2004-11-01

    Near-infrared observations of Europa's disk-integrated opposition surge by Cassini VIMS, first published in Fig. 4 of Brown et al. (2003, Icarus, 164, 461), have now been modeled with the commonly used Hapke photometric function. The VIMS data set emphasizes observations at 16 solar phase angles from 0.4° to 0.6°—the first time the Effect (SHOE) and the Coherent Backscatter Opposition Effect (CBOE). Because of sparse VIMS phase coverage, it is not possible to constrain all the surge parameters at once in a Hapke function that has both SHOE and CBOE; accordingly, we performed separate Hapke fits for SHOE-only and CBOE-only surges. At 2.25 μm, where VIMS data are somewhat noisy, both types of surges can mimic the slope of the VIMS phase curve at SHOE of matching the VIMS phase coefficient at SHOE component, even at wavelengths where Europa is bright.

  5. nowCOAST's Map Service for NOAA NWS NHC Potential Storm Surge Flooding Map

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Map Information: This nowCOAST map service provides maps depicting the latest official NWS Potential Storm Surge Flooding Map for any significant landfalling...

  6. Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Inundation for Categories 2 and 4

    Data.gov (United States)

    U.S. Environmental Protection Agency — The file geodatabase (fgdb) contains the Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Maximum of Maximums (MOM) model for hurricane categories 2 and 4. The...

  7. On the Storm Surge and Sea Level Rise Projections for Infrastructure Risk Analysis and Adaptation

    Science.gov (United States)

    Storm surge can cause coastal hydrology changes, flooding, water quality changes, and even inundation of low-lying terrain. Strong wave actions and disruptive winds can damage water infrastructure and other environmental assets (hazardous and solid waste management facilities, w...

  8. Experimental Evaluation of Lightning-Surge Propagating in Distribution System and Customer's Facility

    National Research Council Canada - National Science Library

    Jun Yoshinaga; Mitsunobu Usui; Toshio Sonoda; Akira Asakawa; Shozo Sekioka

    2004-01-01

    .... In order to verify the current dependency of the grounding electrodes in a distribution system and the behavior of the lightning surges into customer's premise through the power lines, experiments...

  9. Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2014-01-01

    Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

  10. Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

    National Research Council Canada - National Science Library

    Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L; Cardone, Vincent J; Cox, Andrew T; Augustus, Ellsworth H; Colonnese, Christopher P

    2003-01-01

    The long-term goal of this partnership is to establish an operational forecasting system of the wind field and resulting waves and surge impacting the coastline during the approach and landfall of tropical cyclones...

  11. Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

    National Research Council Canada - National Science Library

    Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L

    2005-01-01

    The long-term goal of this partnership is to establish an operational forecasting system of the wind field and resulting waves and surge impacting the coastline during the approach and landfall of tropical cyclones...

  12. Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

    National Research Council Canada - National Science Library

    Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L

    2004-01-01

    The long-term goal of this partnership is to establish an operational forecasting system of the wind field and resulting waves and surge impacting the coastline during the approach and landfall of tropical cyclones...

  13. Hurricane storm surge and amphibian communities in coastal wetlands of northwestern Florida

    Science.gov (United States)

    Gunzburger, M.S.; Hughes, W.B.; Barichivich, W.J.; Staiger, J.S.

    2010-01-01

    Isolated wetlands in the Southeastern United States are dynamic habitats subject to fluctuating environmental conditions. Wetlands located near marine environments are subject to alterations in water chemistry due to storm surge during hurricanes. The objective of our study was to evaluate the effect of storm surge overwash on wetland amphibian communities. Thirty-two wetlands in northwestern Florida were sampled over a 45-month period to assess amphibian species richness and water chemistry. During this study, seven wetlands were overwashed by storm surge from Hurricane Dennis which made landfall 10 July 2005 in the Florida panhandle. This event allowed us to evaluate the effect of storm surge overwash on water chemistry and amphibian communities of the wetlands. Specific conductance across all wetlands was low pre-storm (Media B.V.

  14. Data Assimilation within the Advanced Circulation (ADCIRC) Modeling Framework for Hurricane Storm Surge Forecasting

    KAUST Repository

    Butler, T.

    2012-07-01

    Accurate, real-time forecasting of coastal inundation due to hurricanes and tropical storms is a challenging computational problem requiring high-fidelity forward models of currents and water levels driven by hurricane-force winds. Despite best efforts in computational modeling there will always be uncertainty in storm surge forecasts. In recent years, there has been significant instrumentation located along the coastal United States for the purpose of collecting data—specifically wind, water levels, and wave heights—during these extreme events. This type of data, if available in real time, could be used in a data assimilation framework to improve hurricane storm surge forecasts. In this paper a data assimilation methodology for storm surge forecasting based on the use of ensemble Kalman filters and the advanced circulation (ADCIRC) storm surge model is described. The singular evolutive interpolated Kalman (SEIK) filter has been shown to be effective at producing accurate results for ocean models using small ensemble sizes initialized by an empirical orthogonal function analysis. The SEIK filter is applied to the ADCIRC model to improve storm surge forecasting, particularly in capturing maximum water levels (high water marks) and the timing of the surge. Two test cases of data obtained from hindcast studies of Hurricanes Ike and Katrina are presented. It is shown that a modified SEIK filter with an inflation factor improves the accuracy of coarse-resolution forecasts of storm surge resulting from hurricanes. Furthermore, the SEIK filter requires only modest computational resources to obtain more accurate forecasts of storm surge in a constrained time window where forecasters must interact with emergency responders.

  15. Parameter sensitivity and uncertainty analysis for a storm surge and wave model

    OpenAIRE

    L. A. Bastidas; J. Knighton; S. W. Kline

    2015-01-01

    Development and simulation of synthetic hurricane tracks is a common methodology used to estimate hurricane hazards in the absence of empirical coastal surge and wave observations. Such methods typically rely on numerical models to translate stochastically generated hurricane wind and pressure forcing into coastal surge and wave estimates. The model output uncertainty associated with selection of appropriate model parameters must therefore be addressed. The computational ove...

  16. Simulation of Wind Speed in the Ventilation Tunnel for Surge Tanks in Transient Processes

    Directory of Open Access Journals (Sweden)

    Jiandong Yang

    2016-02-01

    Full Text Available Hydroelectric power plants’ open-type surge tanks may be built in mountains subject to the provision of atmospheric air. Hence, a ventilation tunnel is indispensable. The air flow in the ventilation tunnel is associated with the fluctuation of water-level in the surge tank. There is a great relationship between the wind speed and the safe use and project investment of ventilation tunnels. To obtain the wind speed in a ventilation tunnel for a surge tank during transient processes, this article adopts the one-dimensional numerical simulation method and establishes a mathematical model of a wind speed by assuming the boundary conditions of air discharge for a surge tank. Thereafter, the simulation of wind speed in a ventilation tunnel, for the case of a surge tank during transient processes, is successfully realized. Finally, the effective mechanism of water-level fluctuation in a surge tank and the shape of the ventilation tunnel (including length, sectional area and dip angle for the wind speed distribution and the change process are discovered. On the basis of comparison between the simulation results of 1D and 3D computational fluid dynamics (CFD, the results indicate that the one-dimensional simulation method as proposed in this article can be used to accurately simulate the wind speed in the ventilation tunnel of a surge tank during transient processes. The wind speed fluctuations can be superimposed by using the low frequency mass wave (i.e., fundamental wave and the high frequency elastic wave (i.e., harmonic wave. The water-level fluctuation in a surge tank and the sectional area of the ventilation tunnel mainly affect the amplitude of fundamental and harmonic waves. The period of a fundamental wave can be determined from the water-level fluctuations. The length of the ventilation tunnel has an effect on the period and amplitude of harmonic waves, whereas the dip angle influences the amplitude of harmonic waves.

  17. Comparisons of hurricane-induced storm surge models and their operational use

    Science.gov (United States)

    Choi, J.; Gay, P.; Rigney, J. P.; Doody, M.

    2010-12-01

    The most devastating hazard to human life, habitat and property associated with hurricanes is due to storm surge. The US Navy is often called upon to render humanitarian assistance and aid in disaster recovery in the wake of storm surge events. It is imperative, therefore, that the US Navy, as well as other agencies responsible for national security and safeguarding life and property, evaluate the options available for improvements to operational modeling capabilities. Improvement of storm surge forecast skill has advanced significantly during the past couple of decades as a result of finer resolution, more robust physics, and the inclusion of wave setup and wave-current interaction. Current storm surge models used by United States government agencies, the SLOSH model used by the National Hurricane Center, PCTides by the Naval Oceanographic Office (NAVOCEANO), and ADCIRC by the US Army Corps of Engineers, have several drawbacks such as neglect of tides, wave effects, and insufficient spatial resolution. The purpose of this study is to evaluate and compare available hurricane-induced storm surge models in order to inform the selection of the optimal storm surge model for operational use at NAVOCEANO. This will involve investigation of operational capability and forecast skill of SLOSH, PCTides and ADCIRC, as well as several other storm surge models including CH3D-SSMS, Delft3D and FVCOM. The initial phase, presented in this poster, will entail a literature review to determine and summarize the recent and current state of storm-surge model comparisons in the scientific, industry, and government communities. Consideration will be given to the relative importance of improved inputs to the models (wind-fields and storm track/intensity and associated hurricane prediction models) as compared with model selection.

  18. Dynamical Influence and Operational Impacts of an Extreme Mediterranean Cold Surge

    Science.gov (United States)

    2013-06-01

    INTENTIONALLY LEFT BLANK 1 I. INTRODUCTION A. MOTIVATION 1. Cold Surge and Snowfall Event over Crete On 13 February 2004, an extremely cold air mass from...total snowfall amount and the extreme cold. The high amplitude pattern and extreme conditions were not well forecast. The NSA Souda Bay Command Duty...AND OPERATIONAL IMPACTS OF AN EXTREME MEDITERRANEAN COLD SURGE by Adam Shinabarger June 2013 Thesis Co-Advisors: Patrick Harr Richard

  19. KNDy neurone activation prior to the LH surge of the ewe is disrupted by LPS.

    Science.gov (United States)

    Fergani, C; Routly, J E; Jones, D N; Pickavance, L C; Smith, R F; Dobson, H

    2017-09-01

    In the ewe, steroid hormones act on the hypothalamic arcuate nucleus (ARC) to initiate the GnRH/LH surge. Within the ARC, steroid signal transduction may be mediated by estrogen receptive dopamine-, β-endorphin- or neuropeptide Y (NPY)-expressing cells, as well as those co-localising kisspeptin, neurokinin B (NKB) and dynorphin (termed KNDy). We investigated the time during the follicular phase when these cells become activated (i.e., co-localise c-Fos) relative to the timing of the LH surge onset and may therefore be involved in the surge generating mechanism. Furthermore, we aimed to elucidate whether these activation patterns are altered after lipopolysaccharide (LPS) administration, which is known to inhibit the LH surge. Follicular phases of ewes were synchronised by progesterone withdrawal and blood samples were collected every 2 h. Hypothalamic tissue was retrieved at various times during the follicular phase with or without the administration of LPS (100 ng/kg). The percentage of activated dopamine cells decreased before the onset of sexual behaviour, whereas activation of β-endorphin decreased and NPY activation tended to increase during the LH surge. These patterns were not disturbed by LPS administration. Maximal co-expression of c-Fos in dynorphin immunoreactive neurons was observed earlier during the follicular phase, compared to kisspeptin and NKB, which were maximally activated during the surge. This indicates a distinct role for ARC dynorphin in the LH surge generation mechanism. Acute LPS decreased the percentage of activated dynorphin and kisspeptin immunoreactive cells. Thus, in the ovary-intact ewe, KNDy neurones are activated prior to the LH surge onset and this pattern is inhibited by the administration of LPS. © 2017 Society for Reproduction and Fertility.

  20. The geomorphic imprint of glacier surges into open-marine waters: Examples from eastern Svalbard

    OpenAIRE

    Ottesen, D.; Dowdeswell, Julian Andrew; Bellec, VK; Bjarnadóttir, LR

    2017-01-01

    Seafloor morphology beyond nine tidewater glaciers terminating in open-marine settings in eastern Svalbard has been investigated using multibeam swath-bathymetry. Historical information on tidewater glacier fluctuations over the past century or so shows that the seafloor offshore has been exposed only recently. Most glaciers have been observed to surge or have looped surface moraines indicating past surges. During these ice advances and subsequent retreat, a well-preserved submarine landform ...

  1. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Y. H. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jenne, D. S. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Thresher, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Copping, A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Geerlofs, S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hanna, L. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-01-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  2. Pressure surge in Wendelstein 7-X experimental stellarator facility

    Energy Technology Data Exchange (ETDEWEB)

    Kaliatka, Algirdas; Uspuras, Eugenijus; Kaliatka, Tadas [Lithuanian Energy Institute, Kaunas (Lithuania). Lab. of Nuclear Installation Safety

    2012-05-15

    Fusion is the energy production technology, which could potentially solve problems with growing energy demand of population in the future. Wendelstein 7-X (W7-X) is an experimental stellarator facility currently being built in Greifswald, Germany, which shall demonstrate that in the future energy could be produced in such type of fusion reactors. Lithuanian energy institute (LEI) in the frames of European Fusion Development Agreement (EFDA) program is cooperating with Max Planck Institute for Plasma Physics (IPP, Germany) by performing safety analysis of fusion device W7-X. In this paper the consequences of potential water hammer effects were analysed only for the case, when the plasma vessel is operating in the 'baking' mode. 'Baking' is the mode of facility operation during which the plasma vessel structures are heated up to 150 C in order to release absorbed gases from the surfaces and to pump them out of the plasma vessel before plasma operation. For the analysis the thermal-hydraulic model of target (torus) modules cooling / heating systems in W7-X facility was developed using RELAP5/Mod3.3 code. The performed analyses showed that the pressure pulsations in pipelines of cooling / heating systems are possible only in case of very fast closure of automatic valves in torus modules inlets and check valves in torus modules outlets. The maximum dynamic loading to cooling / heating systems pipelines due to such valves activations is in the range 0.12-0.28 MPa. Such dynamic load is insignificant and integrity of pipelines remains not violated. The pressure surge in pipeline connecting torus module in case of erroneous closure of automatic valve is eliminated due to operation of check valve on pipeline in torus module outlet. (orig.)

  3. Pressure surge in Wendelstein 7-X experimental stellarator facility

    Energy Technology Data Exchange (ETDEWEB)

    Kaliatka, A.; Uspuras, E.; Kaliatka, T. [Lithuanian Energy Inst., Kaunas (Lithuania)

    2011-07-01

    Fusion is the energy production technology, which could potentially solve problems with growing energy demand of population in the future. Wendelstein 7-X (W7-X) is an experimental stellarator facility currently being built in Greifswald, Germany, which shall demonstrate that in the future energy could be produced in such type of fusion reactors. Lithuanian energy institute (LEI) in the frames of European Fusion Development Agreement (EFDA) program is cooperating with Max Planck Institute for Plasma Physics (IPP, Germany) by performing safety analysis of fusion device W7-X. In this paper the consequences of potential water hammer effects were analysed only for the case, when the plasma vessel is operating in the “baking” mode. “Baking” is the mode of facility operation during which the vacuum vessel structures are heated up to 150 C in order to release absorbed gases from the surfaces and to pump them out of the plasma vessel before plasma operation. For the analysis the thermal-hydraulic model of target (torus) modules cooling / heating systems in W7-X facility was developed using RELAP5/Mod3.3 code. The performed analyses showed that the pressure pulsations in pipelines of cooling / heating systems are possible only in case of very fast closure of automatic valves in torus modules inlets and check valves in torus modules outlets. The maximum dynamic loading to cooling / heating systems pipelines due to such valves activations is in the range 0.12 - 0.28 MPa. Such dynamic load is insignificant and integrity of pipelines remains not violated. The pressure surge in pipeline connecting torus module in case of erroneous closure of automatic valve is eliminated due to operation of check valve on pipeline in torus module outlet. (author)

  4. The value of wetlands in protecting southeast louisiana from hurricane storm surges.

    Directory of Open Access Journals (Sweden)

    Edward B Barbier

    Full Text Available The Indian Ocean tsunami in 2004 and Hurricanes Katrina and Rita in 2005 have spurred global interest in the role of coastal wetlands and vegetation in reducing storm surge and flood damages. Evidence that coastal wetlands reduce storm surge and attenuate waves is often cited in support of restoring Gulf Coast wetlands to protect coastal communities and property from hurricane damage. Yet interdisciplinary studies combining hydrodynamic and economic analysis to explore this relationship for temperate marshes in the Gulf are lacking. By combining hydrodynamic analysis of simulated hurricane storm surges and economic valuation of expected property damages, we show that the presence of coastal marshes and their vegetation has a demonstrable effect on reducing storm surge levels, thus generating significant values in terms of protecting property in southeast Louisiana. Simulations for four storms along a sea to land transect show that surge levels decline with wetland continuity and vegetation roughness. Regressions confirm that wetland continuity and vegetation along the transect are effective in reducing storm surge levels. A 0.1 increase in wetland continuity per meter reduces property damages for the average affected area analyzed in southeast Louisiana, which includes New Orleans, by $99-$133, and a 0.001 increase in vegetation roughness decreases damages by $24-$43. These reduced damages are equivalent to saving 3 to 5 and 1 to 2 properties per storm for the average area, respectively.

  5. The insulation coordination and surge arrester design for HTS cable system in Icheon substation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hansang, E-mail: Hansang80@korea.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Yoon, Dong-Hee [Department of New and Renewable Energy, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Lee, Seung-Ryul [Korea Electrotechnology Research Institute, Naeson-dong, Uiwang-si, Gyeonggi-do 437-080 (Korea, Republic of); Yang, Byeong-Mo [Korea Electric Power Research Institute, Munji-dong, Yuseong-gu, Daejeon 305-760 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

    2013-01-15

    Highlights: ► It is necessary to study lightning response of the HTS cable. ► The analytic model has been developed for the HTS cable in the Icheon substation. ► Well-designed surge arrester has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes an insulation coordination and surge arrester design for HTS (High-Temperature Superconducting) cable system in Icheon substation in Korea. In the aspect of the economic analysis, since the HTS cable is very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. Also, in the aspect of the power system reliability, since the HTS cable has much more capacity compared than conventional power cables and the ripple effect from the HTS cable failure may lead to the wide area blackout, an intensive study for insulation coordination from lightning surge is one of the most important considerations. In this paper, the insulation coordination for lightning surge is verified using HTS cable and power equipment models and the design of the proper surge arrester is proposed.

  6. Storm surge evolution and its relationship to climate oscillations at Duck, NC

    Science.gov (United States)

    Munroe, Robert; Curtis, Scott

    2017-07-01

    Coastal communities experience increased vulnerability during storm surge events through the risk of damage to coastal infrastructure, erosion/deposition, and the endangerment of human life. Policy and planning measures attempt to avoid or mitigate storm surge consequences through building codes and setbacks, beach stabilization, insurance rates, and coastal zoning. The coastal emergency management community and public react and respond on shorter time scales, through temporary protection, emergency stockpiling, and evacuation. This study utilizes time series analysis, the Kolmogorov-Smirnov (K-S) test, Pearson's correlation, and the generalized extreme value (GEV) theorem to make the connection between climate oscillation indices and storm surge characteristics intra-seasonally to inter-annually. Results indicate that an El Niño (+ENSO), negative phase of the NAO, and positive phase of the PNA pattern all support longer duration and hence more powerful surge events, especially in winter. Increased surge duration increases the likelihood of extensive erosion, inland inundation, among other undesirable effects of the surge hazard.

  7. Hospital Surge Capacity: A Web-Based Simulation Tool for Emergency Planners.

    Science.gov (United States)

    Toerper, Matthew F; Kelen, Gabor D; Sauer, Lauren M; Bayram, Jamil D; Catlett, Christina; Levin, Scott

    2017-10-18

    The National Center for the Study of Preparedness and Catastrophic Event Response (PACER) has created a publicly available simulation tool called Surge (accessible at http://www.pacerapps.org) to estimate surge capacity for user-defined hospitals. Based on user input, a Monte Carlo simulation algorithm forecasts available hospital bed capacity over a 7-day period and iteratively assesses the ability to accommodate disaster patients. Currently, the tool can simulate bed capacity for acute mass casualty events (such as explosions) only and does not specifically simulate staff and supply inventory. Strategies to expand hospital capacity, such as (1) opening unlicensed beds, (2) canceling elective admissions, and (3) implementing reverse triage, can be interactively evaluated. In the present application of the tool, various response strategies were systematically investigated for 3 nationally representative hospital settings (large urban, midsize community, small rural). The simulation experiments estimated baseline surge capacity between 7% (large hospitals) and 22% (small hospitals) of staffed beds. Combining all response strategies simulated surge capacity between 30% and 40% of staffed beds. Response strategies were more impactful in the large urban hospital simulation owing to higher baseline occupancy and greater proportion of elective admissions. The publicly available Surge tool enables proactive assessment of hospital surge capacity to support improved decision-making for disaster response. (Disaster Med Public Health Preparedness. 2017;page 1 of 10).

  8. Assessing surge capacity expansion plan awareness and attitudes: A survey of Connecticut hospitals.

    Science.gov (United States)

    Smith, Stewart D; Coleman, Suzanne; Johannsson, Mark; Gallant, Noelle; Albanese, Joseph

    This study aimed to ascertain levels of awareness and attitudes of healthcare professionals within four hospital personnel categories, regarding their facility's surge capacity expansion plan. The exploratory descriptive study used a 14-question electronic survey to collect data from hospital personnel in four labour categories. A total of 292 hospital staff from 32 Connecticut hospitals completed the survey, including executive staff mid-level management staff incident command hospital staff and emergency planning contacts. The strongest levels of agreement were found to be: the need for an emergency planning contact, understanding surge expansion roles and responsibilities, and provision of enhanced training and heightened participation in drills and exercises. Statistical significance was found when comparing hospital personnel categories in seven of the 14 survey questions that related to time at hospital, understanding personal role in surge event, understanding staff role in surge event, participating in events to increase surge awareness, understanding alternative care facility roles and responsibilities, understanding incident command system (ICS) roles and responsibilities and the needfor ICS training. Findings demonstrate that some personnel perceive that their institutions are sub-optimally prepared to expand surge capacity. Education and training are important factors that contribute to improving these perceptions and help guide institutional preparedness and response efforts.

  9. Morning blood pressure surge and arterial stiffness in newly diagnosed hypertensive patients.

    Science.gov (United States)

    Kıvrak, Ali; Özbiçer, Süleyman; Kalkan, Gülhan Yüksel; Gür, Mustafa

    2017-06-01

    We aimed to investigate the relationship between the morning blood pressure (BP) surge and arterial stiffness in patients with newly diagnosed hypertension. Three hundred and twenty four (mean age 51.7 ± 11.4 years) patients who had newly diagnosed hypertension with 24 h ambulatory BP monitoring were enrolled. Parameters of arterial stiffness, pulse wave velocity and augmentation index (Aix) were measured by applanation tonometry and aortic distensibility was calculated by echocardiography. Compared with the other groups, pulse wave velocity, day-night systolic BP (SBP) difference (p surge high group. Aortic distensibility values were significantly lower in morning BP surge high group compared to the other groups (p surge was found to be independently associated with pulse wave velocity (β = 0.286, p surge and arterial stiffness which is a surrogate endpoint for cardiovascular diseases. The inverse relationship between morning BP surge and aortic distensibility and direct relation found in our study is new to the literature.

  10. Fluid-structure interaction analysis for pressurizer surge line subjected to thermal stratification

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dong Gu [Korea Institute of Nuclear Safety, 19 Guseong-dong, Yuseong-gu, Daejeon 305-338 (Korea, Republic of); Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jhung, Myung Jo, E-mail: mjj@kins.re.k [Korea Institute of Nuclear Safety, 19 Guseong-dong, Yuseong-gu, Daejeon 305-338 (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2011-01-15

    Research highlights: Temperature of surge line due to stratified flow is defined using CFD analysis. Fluid-structure interaction analysis is performed to investigate the response characteristics due to thermal stress. Fatigue usage factors due to thermal stratification are relatively low. Simplifying temperature distribution in surge line is not always conservative. - Abstract: Serious mechanical damages such as cracks and plastic deformations due to excessive thermal stress caused by thermal stratification have been experienced in several nuclear power plants. In particular, the thermal stratification in the pressurizer surge line has been addressed as one of the significant safety and technical issues. In this study, a detailed unsteady computational fluid dynamics (CFD) analysis involving conjugate heat transfer analysis is performed to obtain the transient temperature distributions in the wall of the pressurizer surge line subjected to stratified internal flows either during out-surge or in-surge operation. The thermal loads from CFD calculations are transferred to the structural analysis code which is employed for the thermal stress analysis to investigate the response characteristics, and the fatigue analysis is ultimately performed. In addition, the thermal stress and fatigue analysis results obtained by applying the realistic temperature distributions from CFD calculations are compared with those by assuming the simplified temperature distributions to identify some requirements for a realistic and conservative thermal stress analysis from a safety point of view.

  11. Surge Pressure Mitigation in the Global Precipitation Measurement Mission Core Propulsion System

    Science.gov (United States)

    Scroggins, Ashley R.; Fiebig, Mark D.

    2014-01-01

    The Global Precipitation Measurement (GPM) mission is an international partnership between NASA and JAXA whose Core spacecraft performs cutting-edge measurements of rainfall and snowfall worldwide and unifies data gathered by a network of precipitation measurement satellites. The Core spacecraft's propulsion system is a blowdown monopropellant system with an initial hydrazine load of 545 kg in a single composite overwrapped propellant tank. At launch, the propulsion system contained propellant in the tank and manifold tubes upstream of the latch valves, with low-pressure helium gas in the manifold tubes downstream of the latch valves. The system had a relatively high beginning-of- life pressure and long downstream manifold lines; these factors created conditions that were conducive to high surge pressures. This paper discusses the GPM project's approach to surge mitigation in the propulsion system design. The paper describes the surge testing program and results, with discussions of specific difficulties encountered. Based on the results of surge testing and pressure drop analyses, a unique configuration of cavitating venturis was chosen to mitigate surge while minimizing pressure losses during thruster maneuvers. This paper concludes with a discussion of overall lessons learned with surge pressure testing for NASA Goddard spacecraft programs.

  12. Identification of storm surge vulnerable areas in the Philippines through the simulation of Typhoon Haiyan-induced storm surge levels over historical storm tracks

    Directory of Open Access Journals (Sweden)

    J. P. Lapidez

    2015-07-01

    Full Text Available Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR on 7 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the storm surge and strong winds. Storm surges up to a height of 7 m were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards (Project NOAH which is the flagship disaster mitigation program of the Department of Science and Technology (DOST of the Philippine government to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948–2013. One product of this study is a list of the 30 most vulnerable coastal areas that can be used as a basis for choosing priority sites for further studies to implement appropriate site-specific solutions for flood risk management. Another product is the storm tide inundation maps that the local government units can use to develop a risk-sensitive land use plan for identifying appropriate areas to build residential buildings, evacuation sites, and other critical facilities and lifelines. The maps can also be used to develop a disaster response plan and evacuation scheme.

  13. A mantle-driven surge in magma supply to Kīlauea Volcano during 2003--2007

    Science.gov (United States)

    Poland, Michael P.; Miklius, Asta; Sutton, A. Jeff; Thornber, Carl R.

    2012-01-01

    The eruptive activity of a volcano is fundamentally controlled by the rate of magma supply. At Kīlauea Volcano, Hawai‘i, the rate of magma rising from a source within Earth’s mantle, through the Hawaiian hotspot, was thought to have been relatively steady in recent decades. Here we show that the magma supply to Kīlauea at least doubled during 2003–2007, resulting in dramatic changes in eruptive activity and the formation of new eruptive vents. An initial indication of the surge in supply was an increase in CO2 emissions during 2003–2004, combined with the onset of inflation of Kīlauea’s summit, measured using the Global Positioning System and interferometric synthetic aperture radar. Inflation was not limited to the summit magma reservoirs, but was recorded as far as 50 km from the summit, implying the existence of a connected magma system over that distance. We also record increases in SO2 emissions, heightened seismicity, and compositional and temperature variations in erupted lavas. The increase in the volume of magma passing through and stored within Kīlauea, coupled with increased CO2 emissions, indicate a mantle source for the magma surge. We suggest that magma supply from the Hawaiian hotspot can vary over timescales of years, and that CO2 emissions could be a valuable aid for assessing variations in magma supply at Kīlauea and other volcanoes.

  14. Influence of a Storm Surge Barrier’s Operation on the Flood Frequency in the Rhine Delta Area

    Directory of Open Access Journals (Sweden)

    Hua Zhong

    2012-05-01

    Full Text Available The Rhine River Delta is crucial to the Dutch economy. The Maeslant barrier was built in 1997 to protect the Rhine estuary, with the city and port of Rotterdam, from storm surges. This research takes a simple approach to quantify the influence of the Maeslant storm surge barrier on design water levels behind the barrier. The dikes in the area are supposed to be able to withstand these levels. Equal Level Curves approach is used to calculate the Rotterdam water levels by using Rhine discharges and sea water levels as input. Their joint probability function generates the occurrence frequency of a certain combination that will lead to a certain high water level in Rotterdam. The results show that the flood frequency in Rotterdam is reduced effectively with the controlled barrier in current and in future scenarios influenced by climate change. In addition, an investigation of the sensitivity of the operational parameters suggests that there is a negligible influence on the high water level frequency when the decision closing water level for the barrier is set higher due to the benefits of navigation (but not exceeding the design safety level 4 m MSL.

  15. Ensemble Kalman Filter data assimilation and storm surge experiments of tropical cyclone Nargis

    Directory of Open Access Journals (Sweden)

    Le Duc

    2015-07-01

    Full Text Available Data assimilation experiments on Myanmar tropical cyclone (TC, Nargis, using the Local Ensemble Transform Kalman Filter (LETKF method and the Japan Meteorological Agency (JMA non-hydrostatic model (NHM were performed to examine the impact of LETKF on analysis performance in real cases. Although the LETKF control experiment using NHM as its driving model (NHM–LETKF produced a weak vortex, the subsequent 3-day forecast predicted Nargis’ track and intensity better than downscaling from JMA's global analysis. Some strategies to further improve the final analysis were considered. They were sea surface temperature (SST perturbations and assimilation of TC advisories. To address SST uncertainty, SST analyses issued by operational forecast centres were used in the assimilation window. The use of a fixed source of SST analysis for each ensemble member was more effective in practice. SST perturbations were found to have slightly positive impact on the track forecasts. Assimilation of TC advisories could have a positive impact with a reasonable choice of its free parameters. However, the TC track forecasts exhibited northward displacements, when the observation error of intensities was underestimated in assimilation of TC advisories. The use of assimilation of TC advisories was considered in the final NHM–LETKF by choosing an appropriate set of free parameters. The extended forecast based on the final analysis provided meteorological forcings for a storm surge simulation using the Princeton Ocean Model. Probabilistic forecasts of the water levels at Irrawaddy and Yangon significantly improved the results in the previous studies.

  16. Optimizing the shape of a surge-and-pitch wave energy collector using a genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, A.P.; Aggidis, G.A.; Widden, M.B. [Engineering Department, Renewable Energy Research Group, Lancaster University, Lancaster LA1 4YR (United Kingdom)

    2010-12-15

    This study forms part of research into the optimization of the shape of a wave energy collector to improve energy extraction using genetic algorithms. The wave energy collector geometry uses a parametric description based upon bi-cubic B-spline surfaces, generated from a relatively small number of control points to reduce the dimensionality of the search space. The collector shapes that are optimized have either one or two planes of symmetry. An elementary cost function is used to determine the performance of each candidate solution. The collectors move in two degrees of freedom (surge-and-pitch), and are optimally tuned to absorb the greatest power from a number of incident regular waves, the results being weighted according to a generalized occurrence distribution. High velocities and large collector volumes are penalized. A benchmark collector shape, against which the optimized shapes are compared, is identified. The overall optimization strategy entails performing repeated runs of the algorithm for a fixed number of generations, then restarting the optimization with the run that produces the best result. An appraisal of the results is made, looking at the performance of all the shapes assessed as well as those deemed the best. (author)

  17. Storm Surge Modelling of Super Typhoon Haiyan Event in Tacloban City, Leyte using MIKE 21 Model

    Science.gov (United States)

    Prelligera, Flor Angel; Caro, Carl Vincent; Ladiero, Christine; Mahar Francisco Lagmay, Alfredo; Lapidez, John Phillip; Malano, Vicente; Agaton, Rojelee; Santiago, Joy; Suarez, John Kenneth

    2014-05-01

    Super Typhoon Haiyan hit the Philippines on 08 November 2013 causing massive destruction to the central part of the country. Arguably the strongest tropical cyclone to make landfall in recorded history, Haiyan caused 6,201 deaths and damages amounting to PhP 36,690,882,497.27 (USD 824,390,091.77). The typhoon also brought about destructive storm surges reaching up to 7 meters in height. A better understanding of storm surge is essential to the development of mechanisms to mitigate the effects of similar events. Thus, a computer simulation of Haiyan with the resulting wave heights and storm surge levels was made using MIKE 21 model -- a software used for many different coastal and marine engineering projects worldwide. Simulations were made using the Hydrodynamic Flexible Mesh (HD FM) model coupled with the Spectral Wave (SW) model of the software. This coupled approach allows accurate calculations of both surge water levels and wave crest heights for overtopping of coastal structures. The maximum mesh flexibility of MIKE 21 allows mesh refinement for the coastal areas of Tacloban City within coarser mesh elements resulting to higher grid accuracy. Input parameters for the simulations of the coastline of Tacloban City, a densely populated coastal community heaviest hit by the storm surges of Haiyan, were obtained from the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) and Japan Meteorological Agency (JMA). Atmospheric conditions such as wind and pressure values were input to a set of regional and local hydrodynamic and spectral wave models. Simulation results were compared with available tidal gauge records and the comparison showed good correlation. Coastal regional inundation maps were then created from the results of the storm surge simulations. These maps or its equivalent should be used to develop and further improve disaster risk management plans for future surge events. These plans include, but are not limited to

  18. Day-night dip and early-morning surge in blood pressure in hypertension: prognostic implications.

    Science.gov (United States)

    Verdecchia, Paolo; Angeli, Fabio; Mazzotta, Giovanni; Garofoli, Marta; Ramundo, Elisa; Gentile, Giorgio; Ambrosio, Giuseppe; Reboldi, Gianpaolo

    2012-07-01

    We investigated the relationship between the day-night blood pressure (BP) dip and the early morning BP surge in an cohort of 3012 initially untreated subjects with essential hypertension. The day-night reduction in systolic BP showed a direct association with the sleep trough (r = 0.564; P surge. Over a mean follow-up period of 8.44 years, 268 subjects developed a major cardiovascular event (composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and heart failure requiring hospitalization) and 220 subjects died. In a Cox model, after adjustment for predictive covariates, including age, sex, diabetes mellitus, cigarette smoking, total cholesterol, left ventricular hypertrophy on ECG, estimated glomerular filtration rate, and average 24-hour systolic BP, a blunted sleep trough (≤ 19.5 mm Hg; quartile 1) and preawakening (≤ 9.5 mm Hg; quartile 1) BP surge was associated with an excess risk of events (hazard ratio, 1.66 [95% CI, 1.14-2.42]; P = 0.009; hazard ratio, 1.71 [95% CI, 1.12-2.71]; P = 0.013). After adjustment for the same covariates, neither the dipping pattern nor the measures of early morning BP surge were independent predictors of mortality. In conclusion, in initially untreated subjects with hypertension, a blunted day-night BP dip was associated with a blunted morning BP surge and vice versa. In these subjects, a blunted morning BP surge was an independent predictor of cardiovascular events, whereas an excessive BP surge did not portend an increased risk of events.

  19. Health systems' "surge capacity": state of the art and priorities for future research.

    Science.gov (United States)

    Watson, Samantha K; Rudge, James W; Coker, Richard

    2013-03-01

    Over the past decade, a number of high-impact natural hazard events, together with the increased recognition of pandemic risks, have intensified interest in health systems' ability to prepare for, and cope with, "surges" (sudden large-scale escalations) in treatment needs. In this article, we identify key concepts and components associated with this emerging research theme. We consider the requirements for a standardized conceptual framework for future research capable of informing policy to reduce the morbidity and mortality impacts of such incidents. Here our objective is to appraise the consistency and utility of existing conceptualizations of health systems' surge capacity and their components, with a view to standardizing concepts and measurements to enable future research to generate a cumulative knowledge base for policy and practice. A systematic review of the literature on concepts of health systems' surge capacity, with a narrative summary of key concepts relevant to public health. The academic literature on surge capacity demonstrates considerable variation in its conceptualization, terms, definitions, and applications. This, together with an absence of detailed and comparable data, has hampered efforts to develop standardized conceptual models, measurements, and metrics. Some degree of consensus is evident for the components of surge capacity, but more work is needed to integrate them. The overwhelming concentration in the United States complicates the generalizability of existing approaches and findings. The concept of surge capacity is a useful addition to the study of health systems' disaster and/or pandemic planning, mitigation, and response, and it has far-reaching policy implications. Even though research in this area has grown quickly, it has yet to fulfill its potential to generate knowledge to inform policy. Work is needed to generate robust conceptual and analytical frameworks, along with innovations in data collection and methodological

  20. Effects of brief postponement of the preovulatory LH surge on ovulation rates and embryo formation in eCG/prostaglandin-treated heifers.

    Science.gov (United States)

    van de Leemput, E E; Vos, P L; Hyttel, P; van den Hurk, R; Bevers, M M; van der Weijden, G C; Dieleman, S J

    2001-01-15

    The aim of this study was to investigate whether prolongation of the period of preovulatory follicular development after superovulation reduces heterogeneity of oocytes of stimulated follicles with respect to the potential to mature, to ovulate, to be fertilized and to develop into embryos. Heifers were treated with eCG on Day 10 and prostaglandin (PG) 48 h later. At the time of eCG administration some of the heifers received a norgestomet implant (N) to suppress the LH surge. After 96 to 104 h, N was removed and an LH surge was induced with GnRH (G) (N/G); the other animals served as controls. Matured oocytes (Experiment A: n=9, 139 [N/G] and 11, 125 [Control] heifers, oocytes), zygotes and oviducts (Experiment B: n=8, 44 [N/G] and 9, 72 [Control] heifers, zygotes) and embryos (Experiment C: n=11, 205 [N/G] and 11, 165 [Control] heifers, embryos) were collected at 22 to 26 h, 38 to 52 h and 7 days after the LH surge, respectively. Hatched blastocyst formation of matured oocytes (Experiment A) was analyzed after 11 days of IVC after IVF. In vivo fertilization rate of zygotes, the presence of periodic acid-Schiff (PAS) positive granules in the oviduct (Experiment B) and stage of development of embryos (Experiment C) were analyzed stereomicroscopically. The mean interval between PG and the LH surge was 53.8+/-3 (SD) (N/G) vs. 42.4+/-4 h (Control). The maximum peripheral estradiol-17beta concentration (529+/-36 [SEM] [N/G] vs. 403+/-17 pmol/L [Control]) and the response to superovulation (25.4+/-2 [N/G] vs. 18.7+/-2 [Control]) were higher in N/G than in Control heifers. Hatched blastocyst formation rate (37.4 [N/G] vs. 33.6% [Control]), in vivo fertilization rate (69.0+/-14 [N/G] vs. 73.0+/-10% [Control]) and the yield of total embryos (3.8+/-1 [N/G] vs. 5.6+/-2 [Control]) did not differ between groups. The percentage of heifers with abundant PAS-positive granules in the distal ampulla (0 [N/G] vs. 31% [Control]) was reduced after N/G treatment. Prolongation of the

  1. Probabilistic storm surge inundation maps for Metro Manila based on Philippine public storm warning signals

    Science.gov (United States)

    Tablazon, J.; Caro, C. V.; Lagmay, A. M. F.; Briones, J. B. L.; Dasallas, L.; Lapidez, J. P.; Santiago, J.; Suarez, J. K.; Ladiero, C.; Gonzalo, L. A.; Mungcal, M. T. F.; Malano, V.

    2015-03-01

    A storm surge is the sudden rise of sea water over the astronomical tides, generated by an approaching storm. This event poses a major threat to the Philippine coastal areas, as manifested by Typhoon Haiyan on 8 November 2013. This hydro-meteorological hazard is one of the main reasons for the high number of casualties due to the typhoon, with 6300 deaths. It became evident that the need to develop a storm surge inundation map is of utmost importance. To develop these maps, the Nationwide Operational Assessment of Hazards under the Department of Science and Technology (DOST-Project NOAH) simulated historical tropical cyclones that entered the Philippine Area of Responsibility. The Japan Meteorological Agency storm surge model was used to simulate storm surge heights. The frequency distribution of the maximum storm surge heights was calculated using simulation results of tropical cyclones under a specific public storm warning signal (PSWS) that passed through a particular coastal area. This determines the storm surge height corresponding to a given probability of occurrence. The storm surge heights from the model were added to the maximum astronomical tide data from WXTide software. The team then created maps of inundation for a specific PSWS using the probability of exceedance derived from the frequency distribution. Buildings and other structures were assigned a probability of exceedance depending on their occupancy category, i.e., 1% probability of exceedance for critical facilities, 10% probability of exceedance for special occupancy structures, and 25% for standard occupancy and miscellaneous structures. The maps produced show the storm-surge-vulnerable areas in Metro Manila, illustrated by the flood depth of up to 4 m and extent of up to 6.5 km from the coastline. This information can help local government units in developing early warning systems, disaster preparedness and mitigation plans, vulnerability assessments, risk-sensitive land use plans, shoreline

  2. InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

    Science.gov (United States)

    Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

    2014-12-01

    Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and S

  3. Observed characteristics of tide-surge interaction along the east coast of India and the head of Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, C.; Unnikrishnan, A.S.

    bands (Prandle and Wolf, 1978; Dixon and Tawn, 1994; Horsburgh and Wilson, 2007). This non-linear interaction between tides and surges has 3 been reported in many other regions such as, off the east coast of Canada, northeastern United States..., to Hiron Point, where interaction is highest, the tidal range and surge heights increase gradually. Earlier studies in the North Sea (Prandle and Wolf, 1978) noticed that interaction increases in direct proportion to both surge height and tidal range...

  4. Parameter sensitivity and uncertainty analysis for a storm surge and wave model

    Directory of Open Access Journals (Sweden)

    L. A. Bastidas

    2016-09-01

    Full Text Available Development and simulation of synthetic hurricane tracks is a common methodology used to estimate hurricane hazards in the absence of empirical coastal surge and wave observations. Such methods typically rely on numerical models to translate stochastically generated hurricane wind and pressure forcing into coastal surge and wave estimates. The model output uncertainty associated with selection of appropriate model parameters must therefore be addressed. The computational overburden of probabilistic surge hazard estimates is exacerbated by the high dimensionality of numerical surge and wave models. We present a model parameter sensitivity analysis of the Delft3D model for the simulation of hazards posed by Hurricane Bob (1991 utilizing three theoretical wind distributions (NWS23, modified Rankine, and Holland. The sensitive model parameters (of 11 total considered include wind drag, the depth-induced breaking γB, and the bottom roughness. Several parameters show no sensitivity (threshold depth, eddy viscosity, wave triad parameters, and depth-induced breaking αB and can therefore be excluded to reduce the computational overburden of probabilistic surge hazard estimates. The sensitive model parameters also demonstrate a large number of interactions between parameters and a nonlinear model response. While model outputs showed sensitivity to several parameters, the ability of these parameters to act as tuning parameters for calibration is somewhat limited as proper model calibration is strongly reliant on accurate wind and pressure forcing data. A comparison of the model performance with forcings from the different wind models is also presented.

  5. A storm surge intensity classification based on extreme water level and concomitant wave height

    Science.gov (United States)

    Dong, Sheng; Gao, Junguo; Li, Xue; Wei, Yong; Wang, Liang

    2015-04-01

    Storm surge is one of the predominant natural threats to coastal communities. Qingdao is located on the southern coast of the Shandong Peninsula in China. The storm surge disaster in Qingdao depends on various influencing factors such as the intensity, duration, and route of the passing typhoon, and thus a comprehensive understanding of natural coastal hazards is essential. In order to make up the defects of merely using the warning water level, this paper presents two statistical distribution models (Poisson Bi-variable Gumbel Logistic Distribution and Poisson Bi-variable Log-normal Distribution) to classify the intensity of storm surge. We emphasize the joint return period of typhoon-induced water levels and wave heights measured in the coastal area of Qingdao since 1949. The present study establishes a new criterion to classify the intensity grade of catastrophic storms using the typhoon surge estimated by the two models. A case study demonstrates that the new criterion is well defined in terms of probability concept, is easy to implement, and fits well the calculation of storm surge intensity. The procedures with the proposed statistical models would be useful for the disaster mitigation in other coastal areas influenced by typhoons.

  6. Rapid wave and storm surge warning system for tropical cyclones in Mexico

    Science.gov (United States)

    Appendini, C. M.; Rosengaus, M.; Meza, R.; Camacho, V.

    2015-12-01

    The National Hurricane Center (NHC) in Miami, is responsible for the forecast of tropical cyclones in the North Atlantic and Eastern North Pacific basins. As such, Mexico, Central America and Caribbean countries depend on the information issued by the NHC related to the characteristics of a particular tropical cyclone and associated watch and warning areas. Despite waves and storm surge are important hazards for marine operations and coastal dwellings, their forecast is not part of the NHC responsibilities. This work presents a rapid wave and storm surge warning system based on 3100 synthetic tropical cyclones doing landfall in Mexico. Hydrodynamic and wave models were driven by the synthetic events to create a robust database composed of maximum envelops of wind speed, significant wave height and storm surge for each event. The results were incorporated into a forecast system that uses the NHC advisory to locate the synthetic events passing inside specified radiuses for the present and forecast position of the real event. Using limited computer resources, the system displays the information meeting the search criteria, and the forecaster can select specific events to generate the desired hazard map (i.e. wind, waves, and storm surge) based on the maximum envelop maps. This system was developed in a limited time frame to be operational in 2015 by the National Hurricane and Severe Storms Unit of the Mexican National Weather Service, and represents a pilot project for other countries in the region not covered by detailed storm surge and waves forecasts.

  7. Introduction on the operational storm surge forecasting system in Korea Operational Oceanographic System (KOOS)

    Science.gov (United States)

    Kwon, Jae-Il; Park, Kwang-Soon; Choi, Jung-Woon; Lee, Jong-Chan; Heo, Ki-Young; Kim, Sang-Ik

    2017-04-01

    During last more than 50 years, 258 typhoons passed and affected the Korean peninsula in terms of high winds, storm surges and extreme waves. In this study we explored the performance of the operational storm surge forecasting system in the Korea Operational Oceanographic System (KOOS) with 8 typhoons from 2010 to 2016. The operation storm surge forecasting system for the typhoon in KOOS is based on 2D depth averaged model with tides and CE (U.S. Army Corps of Engineers) wind model. Two key parameters of CE wind model, the locations of typhoon center and its central atmospheric pressure are based from Korea Meteorological administrative (KMA)'s typhoon information provided from 1 day to 3 hour intervals with the approach of typhoon through the KMA's web-site. For 8 typhoons cases, the overall errors, other performances and analysis such as peak time and surge duration are presented in each case. The most important factor in the storm surge errors in the operational forecasting system is the accuracy of typhoon passage prediction.

  8. Assessment of surge arrester failure rate and application studies in Hellenic high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Christodoulou, C.A.; Fotis, G.P.; Gonos, I.F.; Stathopulos, I.A. [National Technical University of Athens, School of Electrical and Computer Engineering, High Voltage Laboratory, 9 Iroon Politechniou St., Zografou Campus, 157 80 Athens (Greece); Ekonomou, L. [A.S.PE.T.E. - School of Pedagogical and Technological Education, Department of Electrical Engineering Educators, N. Heraklion, 141 21 Athens (Greece)

    2010-02-15

    The use of transmission line surge arresters to improve the lightning performance of transmission lines is becoming more common. Especially in areas with high soil resistivity and ground flash density, surge arresters constitute the most effective protection mean. In this paper a methodology for assessing the surge arrester failure rate based on the electrogeometrical model is presented. Critical currents that exceed arresters rated energy stress were estimated by the use of a simulation tool. The methodology is applied on operating Hellenic transmission lines of 150 kV. Several case studies are analyzed by installing surge arresters on different intervals, in relation to the region's tower footing resistance and the ground flash density. The obtained results are compared with real records of outage rate showing the effectiveness of the surge arresters in the reduction of the recorded failure rate. The presented methodology can be proved valuable to the studies of electric power systems designers intending in a more effective lightning protection, reducing the operational costs and providing continuity of service. (author)

  9. Countercurrent Air-Water Flow in a Scale-Down Model of a Pressurizer Surge Line

    Directory of Open Access Journals (Sweden)

    Takashi Futatsugi

    2012-01-01

    Full Text Available Steam generated in a reactor core and water condensed in a pressurizer form a countercurrent flow in a surge line between a hot leg and the pressurizer during reflux cooling. Characteristics of countercurrent flow limitation (CCFL in a 1/10-scale model of the surge line were measured using air and water at atmospheric pressure and room temperature. The experimental results show that CCFL takes place at three different locations, that is, at the upper junction, in the surge line, and at the lower junction, and its characteristics are governed by the most dominating flow limitation among the three. Effects of inclination angle and elbows of the surge line on CCFL characteristics were also investigated experimentally. The effects of inclination angle on CCFL depend on the flow direction, that is, the effect is large for the nearly horizontal flow and small for the vertical flow at the upper junction. The presence of elbows increases the flow limitation in the surge line, whereas the flow limitations at the upper and lower junctions do not depend on the presence of elbows.

  10. [Analysis of articles published in Chin J Surg since founded in 1951].

    Science.gov (United States)

    Xia, Shuang; Li, Jing

    2016-01-01

    To discuss the characteristics of the articles published in Chin J Surg from 1951 to 2015. The journals and articles of Acad Surg from 1951 to 1952 and Chin J Surg from 1953 to 2015 were analyzed. The subjects, foundation, basic medical study, international cooperation of the articles were recorded. In 65 years, there were 20 090 academic articles published in Chin J Surg. The proportions of general surgery, orthopedic surgery, thoracocardiac surgery, urology surgery and neurosurgery articles were 34.08%, 17.96%, 13.09%, 11.91% and 5.85%, respectively. There were 14.83% (1 728/11 653) articles receiving foundation, and 9.42% (1 817/19 290) articles reporting basic medical study. There were 14.8% articles from international authors and 119 articles with international cooperation. From 2000 to 2003, 29 articles in original English were published. The coverage of Chin J Surg contains all the fields of surgery. It tends to publish the studies focus on clinical issues.Through reinforcing the content plan and optimizing the show form, the more Chinese surgical research achievements could be shared by the surgeons worldwide.

  11. The simultaneous occurrence of surge and discharge extremes for the Rhine delta

    Directory of Open Access Journals (Sweden)

    S. F. Kew

    2013-08-01

    Full Text Available The low-lying Netherlands is at risk from multiple threats of sea level rise, storm surges and extreme river discharges. Should these occur simultaneously, a catastrophe will be at hand. Knowledge about the likelihood of simultaneous occurrence or the so-called "compound effect" of such threats is essential to provide guidance on legislation for dike heights, flood barrier design and water management in general. In this study, we explore the simultaneous threats of North Sea storm surges and extreme Rhine river discharge for the current and future climate in a large 17-member global climate model ensemble. We use a simple approach, taking proxies of north-northwesterly winds over the North Sea and multiple~day precipitation averaged over the Rhine basin for storm surge and discharge respectively, so that a sensitivity analysis is straightforward to apply. By investigating soft extremes, we circumvent the need to extrapolate the data and thereby permit the model's synoptic development of the extreme events to be inspected. Our principle finding based on the climate model data is that, for the current climate, the probability of extreme surge conditions following extreme 20-day precipitation sums is around 3 times higher than that estimated from treating extreme surge and discharge probabilities as independent, as previously assumed. For the future climate (2070–2100, the assumption of independence cannot be rejected, at least not for precipitation sums exceeding 7 days.

  12. Global but not gonadotrope-specific disruption of Bmal1 abolishes the luteinizing hormone surge without affecting ovulation

    DEFF Research Database (Denmark)

    Chu, Adrienne; Zhu, Lei; Blum, Ian D

    2013-01-01

    While there is evidence for a circadian regulation of the preovulatory luteinizing hormone (LH) surge, the contributions of individual tissue clocks to this process remain unclear. We studied female mice deficient in the Bmal1 gene (Bmal1(-/-)), which is essential for circadian clock function......, and found that they lack the proestrus luteinizing hormone (LH) surge. However, spontaneous ovulation on estrus day was unaffected in these animals. Bmal1(-/-) females were also deficient in the proestrus follicle stimulating hormone (FSH) surge, which -as the LH surge- is GnRH-dependent. In the absence...

  13. Machine characteristics, system arrangement, driver and operation effects on surge of dynamic compressor in oil and gas plants

    Energy Technology Data Exchange (ETDEWEB)

    Almasi, Amin

    2012-12-15

    Working in the surge area will result in an unstable compressor operation, exposing the dynamic compressor (centrifugal compressor or axial compressor) to destructive stress, high vibration and other damaging effects. The destructive power of the surge is enormous, ranging from changes in clearances, which result in a penalty in the compressor efficiency, to destruction of parts leading to bearing, rotor or seal replacements. The effects of compressor characteristics, driver type, compressor accessories, vent valve, check valve, trip delay and operation details on surge events and anti-surge system designs are studied. A case study is also discussed. (orig.)

  14. The analysis of dependence between extreme rainfall and storm surge in the coastal zone

    Science.gov (United States)

    Zheng, F.; Westra, S.

    2012-12-01

    Flooding in coastal catchments can be caused by runoff generated by an extreme rainfall event, elevated sea levels due to an extreme storm surge event, or the combination of both processes occurring simultaneously or in close succession. Dependence in extreme rainfall and storm surge arises because common meteorological forcings often drive both variables; for example, cyclonic systems may produce extreme rainfall, strong onshore winds and an inverse barometric effect simultaneously, which the former factor influencing catchment discharge and the latter two factors influencing storm surge. Nevertheless there is also the possibility that only one of the variables is extreme at any given time, so that the dependence between rainfall and storm surge is not perfect. Quantification of the strength of dependence between these processes is critical in evaluating the magnitude of flood risk in the coastal zone. This may become more important in the future as the majority of the coastal areas are threatened by the sea level rise due to the climate change. This research uses the most comprehensive record of rainfall and storm surge along the coastline of Australia collected to-date to investigate the strength of dependence between the extreme rainfall and storm surge along the Australia coastline. A bivariate logistic threshold-excess model was employed to this end to carry out the dependence analysis. The strength of the estimated dependence is then evaluated as a function of several factors including: the distance between the tidal gauge and the rain gauge; the lag between the extreme precipitation event and extreme surge event; and the duration of the maximum storm burst. The results show that the dependence between the extreme rainfall and storm surge along the Australia coastline is statistically significant, although some locations clearly exhibit stronger dependence than others. We hypothesize that this is due to a combination of large-scale meteorological effects as

  15. An Exploration of Wind Stress Calculation Techniques in Hurricane Storm Surge Modeling

    Directory of Open Access Journals (Sweden)

    Kyra M. Bryant

    2016-09-01

    Full Text Available As hurricanes continue to threaten coastal communities, accurate storm surge forecasting remains a global priority. Achieving a reliable storm surge prediction necessitates accurate hurricane intensity and wind field information. The wind field must be converted to wind stress, which represents the air-sea momentum flux component required in storm surge and other oceanic models. This conversion requires a multiplicative drag coefficient for the air density and wind speed to represent the air-sea momentum exchange at a given location. Air density is a known parameter and wind speed is a forecasted variable, whereas the drag coefficient is calculated using an empirical correlation. The correlation’s accuracy has brewed a controversy of its own for more than half a century. This review paper examines the lineage of drag coefficient correlations and their acceptance among scientists.

  16. Parameter identification of ZnO surge arrester models based on genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bayadi, Abdelhafid [Laboratoire d' Automatique de Setif, Departement d' Electrotechnique, Faculte des Sciences de l' Ingenieur, Universite Ferhat ABBAS de Setif, Route de Bejaia Setif 19000 (Algeria)

    2008-07-15

    The correct and adequate modelling of ZnO surge arresters characteristics is very important for insulation coordination studies and systems reliability. In this context many researchers addressed considerable efforts to the development of surge arresters models to reproduce the dynamic characteristics observed in their behaviour when subjected to fast front impulse currents. The difficulties with these models reside essentially in the calculation and the adjustment of their parameters. This paper proposes a new technique based on genetic algorithm to obtain the best possible series of parameter values of ZnO surge arresters models. The validity of the predicted parameters is then checked by comparing the predicted results with the experimental results available in the literature. Using the ATP-EMTP package, an application of the arrester model on network system studies is presented and discussed. (author)

  17. A parabolic model of drag coefficient for storm surge simulation in the South China Sea

    Science.gov (United States)

    Peng, Shiqiu; Li, Yineng

    2015-01-01

    Drag coefficient (Cd) is an essential metric in the calculation of momentum exchange over the air-sea interface and thus has large impacts on the simulation or forecast of the upper ocean state associated with sea surface winds such as storm surges. Generally, Cd is a function of wind speed. However, the exact relationship between Cd and wind speed is still in dispute, and the widely-used formula that is a linear function of wind speed in an ocean model could lead to large bias at high wind speed. Here we establish a parabolic model of Cd based on storm surge observations and simulation in the South China Sea (SCS) through a number of tropical cyclone cases. Simulation of storm surges for independent Tropical cyclones (TCs) cases indicates that the new parabolic model of Cd outperforms traditional linear models. PMID:26499262

  18. Adjusting the Parameters of Metal Oxide Gapless Surge Arresters’ Equivalent Circuits Using the Harmony Search Method

    Directory of Open Access Journals (Sweden)

    Christos A. Christodoulou

    2017-12-01

    Full Text Available The appropriate circuit modeling of metal oxide gapless surge arresters is critical for insulation coordination studies. Metal oxide arresters present a dynamic behavior for fast front surges; namely, their residual voltage is dependent on the peak value, as well as the duration of the injected impulse current, and should therefore not only be represented by non-linear elements. The aim of the current work is to adjust the parameters of the most frequently used surge arresters’ circuit models by considering the magnitude of the residual voltage, as well as the dissipated energy for given pulses. In this aim, the harmony search method is implemented to adjust parameter values of the arrester equivalent circuit models. This functions by minimizing a defined objective function that compares the simulation outcomes with the manufacturer’s data and the results obtained from previous methodologies.

  19. A high resolution study of a hurricane storm surge and inundation in Veracruz, Mexico

    Science.gov (United States)

    Díaz García, Ovel; Zavala Hidalgo, Jorge; Douillet, Pascal

    2014-05-01

    Veracruz is the most populated city along the Mexican shoreline of the Gulf of Mexico and also is the country's largest commercial port. In recent years the city has been affected by hurricanes of medium intensity that have provoked human casualties, property damaged and economic loss. Two of the most recent events were hurricane Karl (2010), which caused a storm surge and severe flooding, and hurricane Ernesto (2012). The purpose of this work is to study, based on high-resolution numerical simulations, scenarios of storm surge flooding using state-of-the-art open source numerical models: the Weather, Research and Forecasting (WRF), and the coupled models ADvanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) for weather and storm surge hindcast, respectively. We also use topography high resolution data from LIDAR and bathymetry from GEBCO 30", the Mexican Navy and nautical charts from Electrical Federal Commission. We present the validation of the models evaluating several statistical parameters against measurements from Acoustic Data Current Profilers, pressure sensors, tide gauge and meteorological stations for these events. In the case of hurricane Karl, it made landfall 15 km north of Veracruz City, reducing the maximum surge along the city shoreline. The hurricane Ernesto made landfall 200 km southeast of the city, too far to have a significant impact. We did some numerical experiments slightly changing the trajectory, reported by the best track data, for these two hurricanes with the purpose of evaluating storm surge scenarios. The results shows that the worst storm surge cases were when the tracks of this hurricanes made landfall south of the city in the range of 30 to 60 km.

  20. Automating Flood Hazard Mapping Methods for Near Real-time Storm Surge Inundation and Vulnerability Assessment

    Science.gov (United States)

    Weigel, A. M.; Griffin, R.; Gallagher, D.

    2015-12-01

    Storm surge has enough destructive power to damage buildings and infrastructure, erode beaches, and threaten human life across large geographic areas, hence posing the greatest threat of all the hurricane hazards. The United States Gulf of Mexico has proven vulnerable to hurricanes as it has been hit by some of the most destructive hurricanes on record. With projected rises in sea level and increases in hurricane activity, there is a need to better understand the associated risks for disaster mitigation, preparedness, and response. GIS has become a critical tool in enhancing disaster planning, risk assessment, and emergency response by communicating spatial information through a multi-layer approach. However, there is a need for a near real-time method of identifying areas with a high risk of being impacted by storm surge. Research was conducted alongside Baron, a private industry weather enterprise, to facilitate automated modeling and visualization of storm surge inundation and vulnerability on a near real-time basis. This research successfully automated current flood hazard mapping techniques using a GIS framework written in a Python programming environment, and displayed resulting data through an Application Program Interface (API). Data used for this methodology included high resolution topography, NOAA Probabilistic Surge model outputs parsed from Rich Site Summary (RSS) feeds, and the NOAA Census tract level Social Vulnerability Index (SoVI). The development process required extensive data processing and management to provide high resolution visualizations of potential flooding and population vulnerability in a timely manner. The accuracy of the developed methodology was assessed using Hurricane Isaac as a case study, which through a USGS and NOAA partnership, contained ample data for statistical analysis. This research successfully created a fully automated, near real-time method for mapping high resolution storm surge inundation and vulnerability for the

  1. Quantification of Storm Surge Using A Python-based ArcGIS Toolbox

    Science.gov (United States)

    Gao, S.; Siverd, C. G.; Bilskie, M. V.; Hagen, S. C.; Alizad, K.

    2016-12-01

    Geographic Information System (GIS) technology allows the organization, manipulation, analysis, and visualization of spatial data (Fischer, 2010). Although GIS provides some operations for spatial analysis, the methods are often only partially implemented and can be difficult to find and use effectively (Rigol-Sanchez et al., 2015). For coastal researchers, development of automated GIS tools is essential to efficiently analyze coastal flood risk from hurricanes. An adaptive GIS toolbox, Quantitative Surge Analysis Tool (QSAT), was developed and implements ArcGIS software and Python scripts to quantify attributes of hurricane storm surge (e.g., average water surface elevation). The python script provides a way to allow researchers to reduce the amount of time spent developing common solutions (Etherington, 2010) and repeating manual operations. The QSAT contains tools that run in the ArcGIS program. These tools compute average water surface elevation, average inundation depth, inundated area, total surge volume, percent of land inundated, and retention time for a given polygonal area. A new shapefile is created with a detail attribute table containing the various surge quantities. The toolbox is designed to directly read data files produced by an ADCIRC storm surge simulation as well as a polygon shapefile defining the areas of interest. The functionality of the QSAT toolbox was tested using Hydrologic Unit Code 12 (HUC 12) polygons of coastal Louisiana and ADCIRC model results from a simulation of Hurricane Gustav. The QSAT aids a streamlined transition of surge quantities across a local medium (i.e. HUC 12s) to better inform stakeholders and lead to improved regional and local decisions.

  2. Dynamics of wave-current-surge interactions in Lake Michigan: A model comparison

    Science.gov (United States)

    Mao, Miaohua; Xia, Meng

    2017-02-01

    Wave, storm surge dynamics, and wave-current-surge interactions (WCSI) were investigated by applying a pair of unstructured-grid-based models to Lake Michigan under two strong wind events. The effects of wind field sources, wind drag coefficient bulk formula, and parameterizations of the bottom friction term were explored to understand lake dynamics. Two wave models were calibrated by using alternative wave physics settings under the 2011 northeasterly wind event. Forced by the southwesterly wind event in 2013, the calibrated models using the atmosphere-ocean fully coupled Climate Forecast System Version 2 wind field were further validated. It is found that the northwesterly winds induced 0.57 m setup near the southwestern coast, whereas the southwesterly winds produced 0.28 m setup and -0.43 m setdown near the northern and southwestern coasts, respectively. The WCSI mostly influence waves and storm surge in shallow-water areas near coasts and islands through depth-induced breaking, current-induced frequency shift and refraction, and wave-induced setup/setdown through wave radiation stress. Owing to the adoption of different discretization algorithms and bottom friction formulations, the modeled storm surge and waves exhibit some variation between the paired models. Even though the storm surge difference with and without WCSI is smaller than that between the two WCSI-coupled models, both circulation models adopt WCSI considering their consistent improvement on model accuracy under both wind events. The analysis of water transport indicates that wind speed, direction, and coastal geometry and bathymetry are also important factors in storm surge.

  3. Health Systems’ “Surge Capacity”: State of the Art and Priorities for Future Research

    Science.gov (United States)

    Watson, Samantha K; Rudge, James W; Coker, Richard

    2013-01-01

    Context Over the past decade, a number of high-impact natural hazard events, together with the increased recognition of pandemic risks, have intensified interest in health systems’ ability to prepare for, and cope with, “surges” (sudden large-scale escalations) in treatment needs. In this article, we identify key concepts and components associated with this emerging research theme. We consider the requirements for a standardized conceptual framework for future research capable of informing policy to reduce the morbidity and mortality impacts of such incidents. Here our objective is to appraise the consistency and utility of existing conceptualizations of health systems’ surge capacity and their components, with a view to standardizing concepts and measurements to enable future research to generate a cumulative knowledge base for policy and practice. Methods A systematic review of the literature on concepts of health systems’ surge capacity, with a narrative summary of key concepts relevant to public health. Findings The academic literature on surge capacity demonstrates considerable variation in its conceptualization, terms, definitions, and applications. This, together with an absence of detailed and comparable data, has hampered efforts to develop standardized conceptual models, measurements, and metrics. Some degree of consensus is evident for the components of surge capacity, but more work is needed to integrate them. The overwhelming concentration in the United States complicates the generalizability of existing approaches and findings. Conclusions The concept of surge capacity is a useful addition to the study of health systems’ disaster and/or pandemic planning, mitigation, and response, and it has far-reaching policy implications. Even though research in this area has grown quickly, it has yet to fulfill its potential to generate knowledge to inform policy. Work is needed to generate robust conceptual and analytical frameworks, along with

  4. Oocyte retrieval timing based on spontaneous luteinizing hormone surge during natural cycle in vitro fertilization treatment.

    Science.gov (United States)

    Bodri, Daniel; Kawachiya, Satoshi; Kondo, Masae; Kato, Ryutaro; Matsumoto, Tsunekazu

    2014-04-01

    To determine the efficiency of oocyte retrieval (OR) timing based on the occurrence of spontaneous LH surge during natural cycle IVF (ncIVF) treatment. Retrospective cohort study. The cohort was divided into five subgroups according to the presumed stage of spontaneous LH surge on scheduling day (1A: before onset; 1B: surge start; 2: ascending slope; 3: peak; and 4: descending slope). Private infertility clinic. Three hundred sixty-five infertile patients who underwent 1,138 ncIVF treatment cycles during 2008-2011. Drug-free ncIVF treatment. Rate of successfully retrieved, fertilized oocytes, cleaved embryos, and live births per scheduled oocyte retrieval. In 61% of the cycles OR was scheduled before or just at the start of the LH surge (groups 1A-1B), whereas in the remaining cases it was scheduled after the surge had already started (groups 2-4). The proportion of cycles with successfully recovered (range, 71%-86%), inseminated (range, 61%-78%), fertilized oocytes (range, 47%-68%), cleaved embryos (range, 45%-66%), and live births (range, 4.1%-9.2%) was not significantly different among subgroups. In ncIVF treatment OR timing based on the occurrence of spontaneous LH surge is feasible, yielding acceptable oocyte recovery, fertilization, and embryo cleavage rates. This strategy combined with a rapid and low-risk OR procedure permits the management of a large ncIVF program on a 7-days-per-week basis within working hours. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  5. The Propagation of a Surge Front on Bering Glacier, Alaska, 2001-2011

    Science.gov (United States)

    Turrin, James; Forster, Richard R.; Larsen, Chris; Sauber, Jeanne

    2013-01-01

    Bering Glacier, Alaska, USA, has a 20 year surge cycle, with its most recent surge reaching the terminus in 2011. To study this most recent activity a time series of ice velocity maps was produced by applying optical feature-tracking methods to Landsat-7 ETM+ imagery spanning 2001-11. The velocity maps show a yearly increase in ice surface velocity associated with the down-glacier movement of a surge front. In 2008/09 the maximum ice surface velocity was 1.5 plus or minus 0.017 kilometers per a in the mid-ablation zone, which decreased to 1.2 plus or minus 0.015 kilometers per a in 2009/10 in the lower ablation zone, and then increased to nearly 4.4 plus or minus 0.03 kilometers per a in summer 2011 when the surge front reached the glacier terminus. The surge front propagated down-glacier as a kinematic wave at an average rate of 4.4 plus or minus 2.0 kilometers per a between September 2002 and April 2009, then accelerated to 13.9 plus or minus 2.0 kilometers per a as it entered the piedmont lobe between April 2009 and September 2010. Thewave seems to have initiated near the confluence of Bering Glacier and Bagley Ice Valley as early as 2001, and the surge was triggered in 2008 further down-glacier in the mid-ablation zone after the wave passed an ice reservoir area.

  6. Availability of a pediatric trauma center in a disaster surge decreases triage time of the pediatric surge population: a population kinetics model

    Science.gov (United States)

    2011-01-01

    Background The concept of disaster surge has arisen in recent years to describe the phenomenon of severely increased demands on healthcare systems resulting from catastrophic mass casualty events (MCEs) such as natural disasters and terrorist attacks. The major challenge in dealing with a disaster surge is the efficient triage and utilization of the healthcare resources appropriate to the magnitude and character of the affected population in terms of its demographics and the types of injuries that have been sustained. Results In this paper a deterministic population kinetics model is used to predict the effect of the availability of a pediatric trauma center (PTC) upon the response to an arbitrary disaster surge as a function of the rates of pediatric patients' admission to adult and pediatric centers and the corresponding discharge rates of these centers. We find that adding a hypothetical pediatric trauma center to the response documented in an historical example (the Israeli Defense Forces field hospital that responded to the Haiti earthquake of 2010) would have allowed for a significant increase in the overall rate of admission of the pediatric surge cohort. This would have reduced the time to treatment in this example by approximately half. The time needed to completely treat all children affected by the disaster would have decreased by slightly more than a third, with the caveat that the PTC would have to have been approximately as fast as the adult center in discharging its patients. Lastly, if disaster death rates from other events reported in the literature are included in the model, availability of a PTC would result in a relative mortality risk reduction of 37%. Conclusions Our model provides a mathematical justification for aggressive inclusion of PTCs in planning for disasters by public health agencies. PMID:21992575

  7. Availability of a pediatric trauma center in a disaster surge decreases triage time of the pediatric surge population: a population kinetics model

    Directory of Open Access Journals (Sweden)

    Grikscheit Tracy C

    2011-10-01

    Full Text Available Abstract Background The concept of disaster surge has arisen in recent years to describe the phenomenon of severely increased demands on healthcare systems resulting from catastrophic mass casualty events (MCEs such as natural disasters and terrorist attacks. The major challenge in dealing with a disaster surge is the efficient triage and utilization of the healthcare resources appropriate to the magnitude and character of the affected population in terms of its demographics and the types of injuries that have been sustained. Results In this paper a deterministic population kinetics model is used to predict the effect of the availability of a pediatric trauma center (PTC upon the response to an arbitrary disaster surge as a function of the rates of pediatric patients' admission to adult and pediatric centers and the corresponding discharge rates of these centers. We find that adding a hypothetical pediatric trauma center to the response documented in an historical example (the Israeli Defense Forces field hospital that responded to the Haiti earthquake of 2010 would have allowed for a significant increase in the overall rate of admission of the pediatric surge cohort. This would have reduced the time to treatment in this example by approximately half. The time needed to completely treat all children affected by the disaster would have decreased by slightly more than a third, with the caveat that the PTC would have to have been approximately as fast as the adult center in discharging its patients. Lastly, if disaster death rates from other events reported in the literature are included in the model, availability of a PTC would result in a relative mortality risk reduction of 37%. Conclusions Our model provides a mathematical justification for aggressive inclusion of PTCs in planning for disasters by public health agencies.

  8. Effect of wind turbine surge motion on rotor thrust and induced velocity

    DEFF Research Database (Denmark)

    Vaal, J.B., de; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    Offshore wind turbines on floating platforms will experience larger motions than comparable bottom fixed wind turbines—for which the majority of industry standard design codes have been developed and validated. In this paper, the effect of a periodic surge motion on the integrated loads and induced...... will be inherently included in the solution of the associated fluid dynamic problem. Through analysis of integrated rotor loads, induced velocities and aerodynamic damping, it is concluded that typical surge motions are sufficiently slow to not affect the wake dynamics predicted by engineering models significantly...

  9. Influence of Model Simplifications Excitation Force in Surge for a Floating Foundation for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Andersen, Morten Thøtt; Hindhede, Dennis; Lauridsen, Jimmy

    2015-01-01

    , thereby, increases the difficulty in wave force determination due to limitations of the commonly used simplified methods. This paper deals with a physical model test of the hydrodynamic excitation force in surge on a fixed three-columned structure intended as a floating foundation for offshore wind...... the influence of incident wave direction and stabilizing heave-plates. The structure can be divided into primary, secondary and tertiary parts, defined by the columns, heave-plates and braces to determine the excitation force in surge. The test results are in good agreement with the numerical computation...

  10. Electroconvulsive therapy, hypertensive surge, blood-brain barrier breach, and amnesia

    DEFF Research Database (Denmark)

    Andrade, Chittaranjan; Bolwig, Tom G

    2014-01-01

    Preclinical and clinical evidence show that electroconvulsive therapy (ECT)-induced intraictal surge in blood pressure may result in a small, transient breach in the blood-brain barrier, leading to mild cerebral edema and a possible leach of noxious substances from blood into brain tissues...... convincing evidence of benefits. It is concluded that there is insufficient support, at present, for the hypothesis that the hypertensive surge during ECT and the resultant blood-brain barrier breach contribute meaningfully to ECT-induced cognitive deficits. Future research should address the subset...

  11. Surge voltages and currents into a customer due to nearby lightning

    Energy Technology Data Exchange (ETDEWEB)

    Ametani, Akihiro; Matsuoka, Kae [Power System Analysis Laboratory, Doshisha University, Kyo-tanabe, Kyoto 610-0321 (Japan); Omura, Hiroshi; Nagai, Yoshiyuki [Power Engineering R and D Center, Kansai Electric Power Co., Amagasaki, Osaka 661-0794 (Japan)

    2009-03-15

    This paper presents experimental results of lightning surges incoming into a customer due to lightning to an antenna of the customer, a pole and a ground nearby the customer, and briefly discusses lightning current distribution in the customer, a distribution line and a telephone line. Based on experimental results, modeling of each component is explained, and EMTP simulations are carried out. The ground voltage rise is represented by a mutual resistance between grounding electrodes. EMTP simulation results have been observed to agree qualitatively with the measured results, and it becomes possible to investigate lightning surges and current distribution in a customer by an EMTP simulation. (author)

  12. Brief communication: The Khurdopin glacier surge revisited - extreme flow velocities and formation of a dammed lake in 2017

    Science.gov (United States)

    Steiner, Jakob F.; Kraaijenbrink, Philip D. A.; Jiduc, Sergiu G.; Immerzeel, Walter W.

    2018-01-01

    Glacier surges occur regularly in the Karakoram, but the driving mechanisms, their frequency and its relation to a changing climate remain unclear. In this study, we use digital elevation models and Landsat imagery in combination with high-resolution imagery from the Planet satellite constellation to quantify surface elevation changes and flow velocities during a glacier surge of the Khurdopin Glacier in 2017. Results reveal that an accumulation of ice volume above a clearly defined steep section of the glacier tongue since the last surge in 1999 eventually led to a rapid surge in May 2017 peaking with velocities above 5000 m a-1, which were among the fastest rates globally for a mountain glacier. Our data reveal that velocities on the lower tongue increase steadily during a 4-year build-up phase prior to the actual surge only to then rapidly peak and decrease again within a few months, which confirms earlier observations with a higher frequency of available velocity data. The surge return period between the reported surges remains relatively constant at ca. 20 years. We show the potential of a combination of repeat Planet and ASTER imagery to (a) capture peak surge velocities that are easily missed by less frequent Landsat imagery, (b) observe surface changes that indicate potential drivers of a surge and (c) monitor hazards associated with a surge. At Khurdopin specifically, we observe that the surging glacier blocks the river in the valley and causes a lake to form, which may grow in subsequent years and could pose threats to downstream settlements and infrastructure in the case of a sudden breach.

  13. Brief communication: The Khurdopin glacier surge revisited – extreme flow velocities and formation of a dammed lake in 2017

    Directory of Open Access Journals (Sweden)

    J. F. Steiner

    2018-01-01

    Full Text Available Glacier surges occur regularly in the Karakoram, but the driving mechanisms, their frequency and its relation to a changing climate remain unclear. In this study, we use digital elevation models and Landsat imagery in combination with high-resolution imagery from the Planet satellite constellation to quantify surface elevation changes and flow velocities during a glacier surge of the Khurdopin Glacier in 2017. Results reveal that an accumulation of ice volume above a clearly defined steep section of the glacier tongue since the last surge in 1999 eventually led to a rapid surge in May 2017 peaking with velocities above 5000 m a−1, which were among the fastest rates globally for a mountain glacier. Our data reveal that velocities on the lower tongue increase steadily during a 4-year build-up phase prior to the actual surge only to then rapidly peak and decrease again within a few months, which confirms earlier observations with a higher frequency of available velocity data. The surge return period between the reported surges remains relatively constant at ca. 20 years. We show the potential of a combination of repeat Planet and ASTER imagery to (a capture peak surge velocities that are easily missed by less frequent Landsat imagery, (b observe surface changes that indicate potential drivers of a surge and (c monitor hazards associated with a surge. At Khurdopin specifically, we observe that the surging glacier blocks the river in the valley and causes a lake to form, which may grow in subsequent years and could pose threats to downstream settlements and infrastructure in the case of a sudden breach.

  14. Potential Effects of SLR and Land-Cover Changes on Hurricane Surge and Damage

    Science.gov (United States)

    Ferreira, C.; Irish, J. L.; Olivera, F.

    2012-12-01

    Hurricanes are one of the most costly natural disasters impacting US coastal areas. Recent studies point towards an increase in damages caused by hurricanes, resulting from sea-level rise (SLR), possible hurricane intensification due to a warmer climate and increasing coastal populations. The SLR is one of the most significant factors of climate change that will impact coastal areas. Besides geometrical changes in coastal bays (i.e., deeper water depth and larger surface area), SLR is also expected to have substantial impacts on the patterns and process of coastal wetlands, thereby affecting surge generation and propagation inside the bays. We analyzed the impacts of SLR on hurricane storm surges, structural building damage, and population and businesses affected for coastal bays located on the Texas central coast. To evaluate the effects of SLR on surges, we considered its impacts on changes in land cover and bay geometry caused by SLR. The analyses were conducted using the hydrodynamic model ADCIRC and a wind and pressure field model (PBL) representing the physical properties of historical hurricane Bret and hypothetical storms. The effects of land cover change were represented within ADCIRC by the changes in the frictional drag at the sea bottom and changes in momentum transfer from the wind to the water column caused by vegetation losses. Simulations were performed using a high-resolution unstructured numerical mesh to study surge response in communities along the coastal bays of Texas. First, we evaluated the impacts of land cover changes due to SLR on the surge response. Second, we evaluated the impacts of neglecting land cover changes due to SLR on the surge response. Finally, we evaluated the overall effect of SLR on the mean maximum surge and the consequent extent of the flooded areas. Although the overall impacts of SLR on surge (water elevation above mean water level) are highly dependent on storm conditions and specific locations within the study area

  15. Surges and Si IV Bursts in the Solar Atmosphere: Understanding IRIS and SST Observations through RMHD Experiments

    Science.gov (United States)

    Nóbrega-Siverio, D.; Martínez-Sykora, J.; Moreno-Insertis, F.; Rouppe van der Voort, L.

    2017-12-01

    Surges often appear as a result of the emergence of magnetized plasma from the solar interior. Traditionally, they are observed in chromospheric lines such as Hα 6563 \\mathringA and Ca II 8542 \\mathringA . However, whether there is a response to the surge appearance and evolution in the Si IV lines or, in fact, in many other transition region lines has not been studied. In this paper, we analyze a simultaneous episode of an Hα surge and a Si IV burst that occurred on 2016 September 03 in active region AR 12585. To that end, we use coordinated observations from the Interface Region Imaging Spectrograph and the Swedish 1-m Solar Telescope. For the first time, we report emission of Si IV within the surge, finding profiles that are brighter and broader than the average. Furthermore, the brightest Si IV patches within the domain of the surge are located mainly near its footpoints. To understand the relation between the surges and the emission in transition region lines like Si IV, we have carried out 2.5D radiative MHD (RMHD) experiments of magnetic flux emergence episodes using the Bifrost code and including the nonequilibrium ionization of silicon. Through spectral synthesis, we explain several features of the observations. We show that the presence of Si IV emission patches within the surge, their location near the surge footpoints and various observed spectral features are a natural consequence of the emergence of magnetized plasma from the interior to the atmosphere and the ensuing reconnection processes.

  16. A New Model for Predicting Dynamic Surge Pressure in Gas and Drilling Mud Two-Phase Flow during Tripping Operations

    Directory of Open Access Journals (Sweden)

    Xiangwei Kong

    2014-01-01

    Full Text Available Investigation of surge pressure is of great significance to the circulation loss problem caused by unsteady operations in management pressure drilling (MPD operations. With full consideration of the important factors such as wave velocity, gas influx rate, pressure, temperature, and well depth, a new surge pressure model has been proposed based on the mass conservation equations and the momentum conservation equations during MPD operations. The finite-difference method, the Newton-Raphson iterative method, and the fourth-order explicit Runge-Kutta method (R-K4 are adopted to solve the model. Calculation results indicate that the surge pressure has different values with respect to different drill pipe tripping speeds and well parameters. In general, the surge pressure tends to increase with the increases of drill pipe operating speed and with the decrease of gas influx rate and wellbore diameter. When the gas influx occurs, the surge pressure is weakened obviously. The surge pressure can cause a significant lag time if the gas influx occurs at bottomhole, and it is mainly affected by pressure wave velocity. The maximum surge pressure may occur before drill pipe reaches bottomhole, and the surge pressure is mainly affected by drill pipe operating speed and gas influx rate.

  17. Phase II Report for SERRI Project No. 80037: Investigation of surge and wave reduction by vegetation (Phase II)

    Science.gov (United States)

    To better understand and quantify the effectiveness of wetland vegetation in mitigating the impact of hurricane and storm surges, this SERRI project (No. 80037) examined surge and wave attenuation by vegetation through laboratory experiments, field observations and computational modeling. It was a c...

  18. Nimodipine, a calcium channel blocker, delays the spontaneous LH surge in women with regular menstrual cycles: a prospective pilot study.

    Science.gov (United States)

    Nayot, Dan; Klachook, Shany; Casper, Robert F

    2013-02-07

    Currently GnRH analogue injections are used to prevent premature LH surges in women undergoing assisted reproductive technology. This was a pilot study to determine the safety and effectiveness of nimodipine, an oral calcium channel blocker, to delay the mid-cycle spontaneous LH surge in women with regular menstrual cycles. Eight women with regular menstrual cycles self-monitored three consecutive cycles for the day of an LH surge by daily urine assay. The first and third cycles were observatory. In the second cycle, subjects took nimodipine 60 mg by mouth three times daily for four days, starting two days prior to the expected LH surge day based on cycle one. The LH surge day in cycle 2 (nimodipine) was significantly delayed in comparison to both observatory cycle 1 (15.5+/-3.4 vs 14.0+/-2.8 days; p=0.033) and cycle 3 (15.1+/-3.5 vs 13.1+/-2.4 days; p=0.044). There was no difference in the LH surge day between the two observatory cycles (13.4+/-2.4 vs 13.1+/-2.4 days; p=0.457). Three patients experienced a mild headache. There was a statistically significant delay in the spontaneous LH surge day in the treatment cycle in comparison to both observatory cycles. Nimopidine should be further investigated as an oral alternative to delay a spontaneous LH surge.

  19. The climatology of East Asian winter monsoon and cold surges from 1979--1995 NCEP/NCAR reanalyses

    Energy Technology Data Exchange (ETDEWEB)

    Yi Zhang; Sperber, K.; Boyle, J.

    1996-04-01

    The East Asian winter monsoon, which is associated with the Siberian high and active cold surges, is one of the most energetic monsoon circulation systems. The dramatic shift of northeasterlies and the outbreak of cold surges dominate the winter weather and local climate in the East Asian region, and may exert a strong impact on the extratropical and tropical planetary-scale circulations and influence the SSTs in the tropical western Pacific. General characteristics of the winter monsoon and cold surges and their possible link with tropical disturbances are revealed in many observational studies. Little attention has been given to the climatological aspects of the winter monsoon and cold surges. The purpose of this study is to compile and document the East Asian mean winter circulation, and present the climatology of cold surges and the Siberian high based on the 1979--1995 NCEP/NCAR reanalyses. Of particular interest is the interannual variation of winter monsoon circulation and cold surge events. Given that the cold surge activity and the Indonesian convection are much reduced during the 1982--83 period, one of the goals is to determine whether there exists a statistically significant relationship between ENSO and the interannual variation of winter monsoon and cold surges.

  20. Influence of a storm surge barrier’s operation on the flood frequency in the Rhine Delta area

    NARCIS (Netherlands)

    Zhong, H.; Van Overloop, P.J.; Van Gelder, P.; Rijcken, T.

    2012-01-01

    The Rhine River Delta is crucial to the Dutch economy. The Maeslant barrier was built in 1997 to protect the Rhine estuary, with the city and port of Rotterdam, from storm surges. This research takes a simple approach to quantify the influence of the Maeslant storm surge barrier on design water

  1. Discectomy-related information on the internet: does the quality follow the surge?

    Science.gov (United States)

    Elhassan, Yahya; Sheridan, Gerard; Nassiri, Mujtaba; Osman, Mugtaba; Kiely, Pat; Noel, Jacques

    2015-01-15

    A quality-control Internet-based study using recognized quality-scoring systems. To evaluate the quality of information available on the Internet. Quality of health information on the Internet is of much concern and the emphasis for appraisal of Internet Web sites is needed. This study is to determine if it has improved with the surge in Internet usage. The 3 most commonly used search engines were identified and a search for "Discectomy" was performed on each. Two reviewers categorized the Web sites according to their types and the quality of each was assessed using recognized scoring systems including the Journal of the American Medical Association (JAMA) benchmark, DISCERN score, and discectomy-specific content score. The quality of the information was also assessed according to the presence and absence of the Health on the Net code. Fifty-three Web sites were identified, and analyzed. Commercial Web sites were predominant, 24 of them were identified, 7 were governmental, 6 were produced by physicians, none were produced by allied health professionals, 3 were academic, 4 were public health information Web sites, 4 were attached to social media and discussion groups, 3 were related to media, and 2 were unspecified. Internet sites with a Health on the Net code demonstrated significantly higher quality than those without the code (P information Web sites attained the highest overall DISCERN and discectomy-specific scores followed by Web sites of the government and nonprofit organizations. The overall quality of information regarding discectomy remains poor and variable despite an exponential increase in the number of users and Web sites, with a slight trend toward improvement, only 20% to 30% are of good quality, compared with that 10 years ago (Net code is a very reliable marker for health information quality.

  2. Perancangan Sistem Surge Absorber Untuk Mencegah Terjadinya Waterhammer Pada Pipeline Sistem Pendistribusian Avtur Di DPPU Pertamina - Bandara Ngurah Rai

    Directory of Open Access Journals (Sweden)

    Agung Dwi Sulaksono

    2013-03-01

    Full Text Available Aliran fluida transient erat kaitannya dengan fenomena fluida yang dikenal dengan water hammer. Water hammer yang tidak terkendali dapat berakibat buruk pada instalasi sistem perpipaan. Untuk menghindari dampak buruk keberdaan water hammer dapat dilakukan dengan cara memasang komponen perpipaan, salah satunya adalah surge absorber. Sehubungan dengan rencana pengembangan jalur perpipaan serta penambahan kapasitas pompa DPPU Pertamina maka diperlukan kajian mengenai performansi surge absorber yang telah terpasang dan surge absorber yang dibutuhkan untuk mencegah water hammer pada header pit sistem perpipaan DPPU Pertamina yang baru. Kajian tersebut dilakukan dengan cara membuat simulasi yang menmggunakan Method Of Characteristic untuk menyelesaikan persamaan dasar water hammer. Dari hasil kajian yang telah dilakukan, diketahui bahwa delapan buah surge absorber yang terpasang pada sistem perpipaan DPPU Pertamina memiliki volume gas yang masih berada pada range kerjanya . Sedangkan untuk mengatasi water hammer pada jalur pipa tambahan, diperlukan penambahan 4 buah surge absorber yang diletakkan pada sistem perpipaan yang baru.

  3. Current & future vulnerability of sarasota county Florida to hurricane storm surge & sea level rise

    Science.gov (United States)

    Frazier, T.; Wood, N.; Yarnal, B.

    2008-01-01

    Coastal communities in portions of the United States are vulnerable to storm-surge inundation from hurricanes and this vulnerability will likely increase, given predicted rises in sea level from climate change and growing coastal development. In this paper, we provide an overview of research to determine current and future societal vulnerability to hurricane storm-surge inundation and to help public officials and planners integrate these scenarios into their long-range land use plans. Our case study is Sarasota County, Florida, where planners face the challenge of balancing increasing population growth and development with the desire to lower vulnerability to storm surge. Initial results indicate that a large proportion of Sarasota County's residential and employee populations are in areas prone to storm-surge inundation from a Category 5 hurricane. This hazard zone increases when accounting for potential sea-level-rise scenarios, thereby putting additional populations at risk. Subsequent project phases involve the development of future land use and vulnerability scenarios in collaboration with local officials. Copyright ASCE 2008.

  4. Idealised modelling of storm surges in large-scale coastal basins

    NARCIS (Netherlands)

    Chen, Wenlong

    2015-01-01

    Coastal areas around the world are frequently attacked by various types of storms, threatening human life and property. This study aims to understand storm surge processes in large-scale coastal basins, particularly focusing on the influences of geometry, topography and storm characteristics on the

  5. Building with Nature: in search of resilient storm surge protection strategies

    NARCIS (Netherlands)

    van Slobbe, E.; de Vriend, Huib J.; Aarninkhof, S.G.J.; Lulofs, Kristiaan R.D.; de Vries, M.; Dircke, P.

    2013-01-01

    Low-lying, densely populated coastal areas worldwide are under threat, requiring coastal managers to develop new strategies to cope with land subsidence, sea-level rise and the increasing risk of storm-surge-induced floods. Traditional engineering approaches optimizing for safety are often

  6. Specific Consideration on Superior Performance and Evaluation Methods of Polymer-housed Surge Arresters

    Science.gov (United States)

    Ishizaki, Yoshihiro; Kobayashi, Misao; Suzuki, Hironori; Futagami, Koichi

    It is very suitable to select the polymer materials for the housings of surge arresters (SAs), because the polymer materials are generally soft and light weight. Therefore, many kinds of polymer-housed SAs using various polymer materials have been developed, and expanding into many countries. Considering these backgrounds, the JEC technical report (JEC-TR) 23002-2008; polymer-housed surge arrester(1) has been established based on the existent relevant standards of arresters, such as JEC-2371-2003; Insulator-housed surge arresters(2) and IEC 60099-4 Edition 2.2, Metal-oxide surge arresters (MOSAs) without gaps for a.c. systems(3) in order to introduce the technology and provide a common guide for testing of polymer-housed SAs. According as the JEC-TR, the various new applications of the polymer-housed SAs, which are caused by superior advantages such as compact, light weight, safe failure mode, anti-seismic performance, anti-pollution performance and cost efficiency design, have been realized recently in Japan. Therefore, this paper gives specific consideration on the superior performance of the polymer-housed SAs and the evaluation methods of the polymer-housed SAs, because there are some issues in the existent standards to be solved.

  7. An Idealized Meteorological-Hydrodynamic Model for Exploring Extreme Storm Surge Statistics in the North Sea

    NARCIS (Netherlands)

    Van Ledden, M.; Van den Berg, N.J.F.; De Jong, M.S.; Van Gelder, P.H.A.J.M.; Den Heijer, C.; Vrijling, J.K.; Jonkman, S.N.; Roos, P.C.; Hulscher, S.J.M.H.; Lansen, A.J.

    2014-01-01

    This paper explores an alternative method to determine extreme surge levels at the Dutch Coast. For this exploration, specific focus is on the extreme water level at Hoek van Holland, The Netherlands. The alternative method has been based on a joint probability model of the storm characteristics at

  8. Hydrodynamic forces and ship motions induced by surges in a navigation lock

    NARCIS (Netherlands)

    Kalkwijk, J.P.T.

    1973-01-01

    This thesis treats the fluid and ship motion in a navigation lock and their mutual interaction as caused by surges, which occur in the chamber during filling or emptying. The other phenomena, which possibly play a role during these processes are ignored. The considerations of this treatise hold good

  9. Efficiency and safety of percuSurge distal protection device in acute ...

    African Journals Online (AJOL)

    user

    2011-04-25

    Apr 25, 2011 ... In this study, we evaluate the efficiency and safety of PercuSurge DPD in coronary intervention in patients with ... (TIMI)grades and myocardial blush grades (MBG) were performed in all cases after emergency PCI. The device was .... The duration of cine filming was required to exceed 3 cardiac cycles in the ...

  10. Methodology for the assessment of possible damages in low voltage equipment due to lightning surges

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, Nelson M.; Kagan, Nelson [University of Sao Paulo (USP), SP (Brazil)], Emails: matsuonm@usp.br, nelsonk@pea.usp.br; Domingues, Ivo T. [AES Eletropaulo, SP (Brazil); Jesus, Nelson C. de [AES Sul, Porto Alegre, RS (Brazil); Silva, Marcelo H.I. da [Grupo Rede, Sao Paulo, SP (Brazil); Takauti, Edson H. [Bandeirante, Sao Paulo, SP (Brazil)

    2007-07-01

    This paper deals with the development of a methodology to assess the possibility of equipment damages in low voltage customers due to lightning surges. The main objective is to incorporate this methodology in a computation system that supports distribution companies to determine the possible causes of equipment damages claimed by customers and to decide whether the claims are to be reimbursed or not. The proposed methodology determines whether a specific customer could be affected by a lightning strike according to his/her location and to the lightning main parameters, by using data from a lightning detection system and from the specific equipment surge withstand capability. A specific study using ATP (Alternative Transients Program) was carried out to assess the propagation of lightning surges in electric power distribution systems and their impact over low voltage customers. On the other hand, the withstand capability of the main household appliances was determined by a series of tests carried out in the University's power quality laboratory. The paper details the modeling used for simulation, such as network configuration, grounding points, and modelling of insulator flashover, distribution transformer, low voltage loads. It also presents some results regarding the evaluation of over voltages in low voltage customers installations. A practical method is proposed for assessing the possibility of equipment damage and describes how the existing uncertainties were handled. Also, some issues regarding the withstand capability of electric household appliances to lightning surges are discussed and some results of the laboratory tests are presented. (author)

  11. Impact of multiple glacial surges - a geomorphological map from Brúarjökull, East Iceland

    DEFF Research Database (Denmark)

    Kjær, Kurt H.; Korsgaard, Niels Jákup; Schomacker, Anders

    2008-01-01

    Simultaneously with geological field investigations at the surge-type glacier Bruarjokull in August 2003, aerial photographs covering the central part of the glacier including the Kringilsarrani area were recorded with the purpose of mapping glacial landforms. A glacial geomorphological map has...

  12. Impact of hydrogeological factors on groundwater salinization due to ocean-surge inundation

    Science.gov (United States)

    Yang, Jie; Zhang, Huichen; Yu, Xuan; Graf, Thomas; Michael, Holly A.

    2018-01-01

    Ocean surges cause seawater inundation of coastal inland areas. Subsequently, seawater infiltrates into coastal aquifers and threatens the fresh groundwater resource. The severity of resulting salinization can be affected by hydrogeological factors including aquifer properties and hydrologic conditions, however, little research has been done to assess these effects. To understand the impacts of hydrogeological factors on groundwater salinization, we numerically simulated an ocean-surge inundation event on a two-dimensional conceptual coastal aquifer using a coupled surface-subsurface approach. We varied model permeability (including anisotropy), inland hydraulic gradient, and recharge rate. Three salinization-assessment indicators were developed, based on flushing time, depth of salt penetration, and a combination of the two, weighted flushing time, with which the impact of hydrogeological factors on groundwater vulnerability to salinization were quantitatively assessed. The vulnerability of coastal aquifers increases with increasing isotropic permeability. Low horizontal permeability (kx) and high vertical permeability (kz) lead to high aquifer vulnerability, and high kx and low kz lead to low aquifer vulnerability. Vulnerability decreases with increasing groundwater hydraulic gradient and increasing recharge rate. Additionally, coastal aquifers with a low recharge rate (R ≤ 300 mm yr-1) may be highly vulnerable to ocean-surge inundation. This study shows how the newly introduced indicators can be used to quantitatively assess coastal aquifer vulnerability. The results are important for global vulnerability assessment of coastal aquifers to ocean-surge inundation.

  13. the major cause of observed erosion surge on the beaches north

    African Journals Online (AJOL)

    Mgina

    hydrodynamic conditions as the effective cause on the short term and at local scales. This work looks at the potential of the extreme winds as the major cause of the alarming erosion rates north of Dar es. Salaam. Figure 1: Kunduchi – Msasani beach where erosion surges are reported. LOCATION AND. GEOMORPHOLOGY.

  14. ISSN 2073 ISSN 2073-9990 East Cent. Afr. J. surg. (Online) 9990 ...

    African Journals Online (AJOL)

    DELL

    Rosen MR, Saigal K, Evans J, Keane WM. A review of the endoscopic approach to the pituitary through the sphenoid Sinus. Curr Opin in Otolaryngol & Head Neck Surg 2006; 14: 6-13. 16. Kawamata T, Iseki H, Ishizaki R, Hori T. Minimally invasive endoscope-assisted endonasal trans-sphenoidal microsurgery for pituitary ...

  15. Surge of Hispar Glacier, Pakistan, between 2013 and 2017 detected from remote sensing observations

    Science.gov (United States)

    Rashid, Irfan; Abdullah, Tariq; Glasser, Neil F.; Naz, Heena; Romshoo, Shakil Ahmad

    2018-02-01

    This study analyses the behaviour of an actively surging glacier, Hispar, in Pakistan using remote sensing methods. We used 15 m panchromatic band of Landsat 8 OLI from 2013 to 2017 to assess the changes in glacier velocity, glacier geomorphology and supraglacial water bodies. For the velocity estimation, correlation image analysis (CIAS) was used, which is based on normalized cross-correlation (NCC) of satellite data. On-screen digitization was employed to quantify changes in the glacier geomorphology and dynamics of supraglacial water bodies on the glacier. Our velocity estimates indicate that the upper part of the glacier is presently undergoing an active surge which not only affects the debris distribution but also impacts the development of supraglacial water bodies. Velocities in the actively surging part of the main glacier trunk and its three tributaries reach up to 900 m yr- 1. The surge of Hispar also impacts the distribution of supraglacial debris causing folding of the medial moraines features present on the glacier surface. Changes in the number and size of supraglacial lakes and ponds were also observed during the observation period from 2013 to 2017.

  16. ISSN 2073 ISSN 2073-9990 East Cent. Afr. J. surg. (Online) 9990 ...

    African Journals Online (AJOL)

    DELL

    9990 East Cent. Afr. J. surg. (Online) e text]. COSECSA/ASEA Publication East and Central African Journal of Surgery. East and Central African Journal of Surgery. 2012 March/ April;17(1). April;17(1). Page 81 selecting the most appropriate incision site. Ample local anesthetic with 0.5% lidocaine is used to infiltrate the skin ...

  17. Improving short-range ensemble Kalman storm surge forecasting using robust adaptive inflation

    NARCIS (Netherlands)

    Altaf, M.U.; Butler, T.; Luo, X.; Dawson, C.; Mayo, T.; Hoteit, I.

    2013-01-01

    This paper presents a robust ensemble filtering methodology for storm surge forecasting based on the singular evolutive interpolated Kalman (SEIK) filter, which has been implemented in the framework of the H? filter. By design, an H? filter is more robust than the common Kalman filter in the sense

  18. East China Sea Storm Surge Modeling and Visualization System: The Typhoon Soulik Case

    Directory of Open Access Journals (Sweden)

    Zengan Deng

    2014-01-01

    Full Text Available East China Sea (ECS Storm Surge Modeling System (ESSMS is developed based on Regional Ocean Modeling System (ROMS. Case simulation is performed on the Typhoon Soulik, which landed on the coastal region of Fujian Province, China, at 6 pm of July 13, 2013. Modeling results show that the maximum tide level happened at 6 pm, which was also the landing time of Soulik. This accordance may lead to significant storm surge and water level rise in the coastal region. The water level variation induced by high winds of Soulik ranges from −0.1 to 0.15 m. Water level generally increases near the landing place, in particular on the left hand side of the typhoon track. It is calculated that 0.15 m water level rise in this region can cause a submerge increase of ~0.2 km2, which could be catastrophic to the coastal environment and the living. Additionally, a Globe Visualization System (GVS is realized on the basis of World Wind to better provide users with the typhoon/storm surge information. The main functions of GVS include data indexing, browsing, analyzing, and visualization. GVS is capable of facilitating the precaution and mitigation of typhoon/storm surge in ESC in combination with ESSMS.

  19. Hindcast and validation of Hurricane Ike waves, forerunner, and storm surge

    NARCIS (Netherlands)

    Hope, M.E.; Westerink, J.J.; Kennedy, A.B.; Kerr, P.C.; Dietrich, J.C.; Dawson, C.; Bender, C.J.; Smith, J.M.; Jensen, R.E.; Zijlema, M.; Holthuijsen, L.H.; Luettich, R.A.; Powell, M.D.; Cardone, V.J.; Cox, A.T.; Pourtaheri, H.; Roberts, H.J.; Atkinson, J.H.; Tanaka, S.; Westerink, H.J.; Westerink, L.G.

    2013-01-01

    Hurricane Ike (2008) made landfall near Galveston, Texas, as a moderate intensity storm. Its large wind field in conjunction with the Louisiana-Texas coastline's broad shelf and large scale concave geometry generated waves and surge that impacted over 1000 km of coastline. Ike's complex and varied

  20. Analysis of a compounding surge and precipitation event in the Netherlands

    NARCIS (Netherlands)

    van den Hurk, B.J.J.M.; van Meijgaard, E.; van der Valk, P.H.M.; van Heeringen, K.-J.; de Gooijer, J.

    2015-01-01

    Hydrological extremes in coastal areas in the Netherlands often result from a combination of anomalous (but not necessarily extreme) conditions: storm surges preventing the ability to discharge water to the open sea, and local precipitation generating excessive water levels in the inland area. A

  1. Sensitivity of tropical cyclone surge risk to changes in sea level and sea surface temperature

    Science.gov (United States)

    Hoffman, Ross; Dailey, Peter; Hopsch, Susanna; Ponte, Rui; Quinn, Katherine; Hill, Emma

    2010-05-01

    Sea level is projected to continue to rise. Even small differences in sea level have significant impacts on storm surge risk to life and property. Projecting losses to property in the future as sea level rises is made difficult by several factors that result in uncertainty in the future inventory of real estate along the coast. Here the focus is directly on property loss for the current real estate inventory. In addition climate change will affect many other geophysical factors. We make a first order attempt to include the impact on storm surge risk of the interaction of rising sea surface temperatures with rising sea level. The change in expected risk is quantified for a sea level rise immediately by an amount equivalent to a conservative projection of sea level rise over twenty years. Upper and lower bounds of this projection are also evaluated. We then apply a state-of-the-science catastrophe model to quantify the change in risk of storm surge to property along the U.S.~Gulf and East Coasts. In twenty years, we estimate that U.S. expected annual losses will increase by 8% due to sea level rise alone and by 19% if tropical storm activity increases to a level similar to that of those recent years that had warmer than normal SST. There is considerable variation with location of these results reflecting the varying rates of sea-level rise and vulnerability to storm surge along the coast .

  2. The Major Cause of Observed Erosion Surge on the Beaches North ...

    African Journals Online (AJOL)

    Surges in coastal erosion north of Dar es Salaam city have been documented from 1977 to the early 1980s and around 1997/98. Analysis of the wind data shows that the documented increase in coastal erosion coincided with increased wind speeds. Extreme winds in excess of 10-11 m s-1 were experienced during ...

  3. ISSN 2073 ISSN 2073-9990 East Cent. Afr. J. surg. (Online) 9990 ...

    African Journals Online (AJOL)

    Prof Kakande

    prostate and high power GreenLight™ laser therapy using isotopic measure of red blood cells volume. J Endourol 2011; 25(10):1655-9. 2. Musau P Morbidity and mortality of surgically treated urological patients in a tertiary centre in. Western Kenya. Annal Afr Surg 2012; 9:28-31. 3. Mungai P, Saula P Experience of blood ...

  4. An experimental description of the flow in a centrifugal compressor from alternate stall to surge

    Science.gov (United States)

    Moënne-Loccoz, V.; Trébinjac, I.; Benichou, E.; Goguey, S.; Paoletti, B.; Laucher, P.

    2017-08-01

    The present paper gives the experimental results obtained in a centrifugal compressor stage designed and built by SAFRAN Helicopter Engines. The compressor is composed of inlet guide vanes, a backswept splittered unshrouded impeller, a splittered vaned radial diffuser and axial outlet guide vanes. Previous numerical simulations revealed a particular S-shape pressure rise characteristic at partial rotation speed and predicted an alternate flow pattern in the vaned radial diffuser at low mass flow rate. This alternate flow pattern involves two adjacent vane passages. One passage exhibits very low momentum and a low pressure recovery, whereas the adjacent passage has very high momentum in the passage inlet and diffuses efficiently. Experimental measurements confirm the S-shape of the pressure rise characteristic even if the stability limit experimentally occurs at higher mass flow than numerically predicted. At low mass flow the alternate stall pattern is confirmed thanks to the data obtained by high-frequency pressure sensors. As the compressor is throttled the path to instability has been registered and a first scenario of the surge inception is given. The compressor first experiences a steady alternate stall in the diffuser. As the mass flow decreases, the alternate stall amplifies and triggers the mild surge in the vaned diffuser. An unsteady behavior results from the interaction of the alternate stall and the mild surge. Finally, when the pressure gradient becomes too strong, the alternate stall blows away and the compressor enters into deep surge.

  5. On the effect of pulsating flow on surge margin of small centrifugal compressors for automotive engines

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, J.; Climent, H.; Guardiola, C.; Tiseira, A. [CMT-Motores Termicos, Universidad Politecnica de Valencia (Spain); Camino de Vera s/n, E 46022, Valencia (Spain)

    2009-11-15

    Surge is becoming a limiting factor in the design of boosting systems of downsized diesel engines. Although standard compressor flowcharts are used for the selection of those machines for a given application, on-engine conditions widely differ from steady flow conditions, thus affecting compressor behaviour and consequently surge phenomenon. In this paper the effect of pulsating flow is investigated by means of a steady gas-stand that has been modified to produce engine-like pulsating flow. The effect of pressure pulses' amplitude and frequency on the compressor surge line location has been checked. Results show that pulsating flow in the 40-67 Hz range (corresponding to characteristic pulsation when boosting an internal combustion engine) increases surge margin. This increased margin is similar for all the tested frequencies but depends on pulsation amplitude. In a further step, a non-steady compressor model is used for modelling the tests, thus allowing a deeper analysis of the involved phenomena. Model results widely agree with experimental results. (author)

  6. Use of the Colorado SURGE System for Continuing Education for Civil Engineers.

    Science.gov (United States)

    Fead, J. W. N.

    The Colorado State University Resources in Graduate Education (SURGE) program is described in this report. Since it is expected that not all the participants in a graduate engineering program will be able to attend university-based lectures, presentations are video-taped and transported to industrial plants, engineering offices, and other…

  7. Prognostic value of the morning blood pressure surge in 5645 subjects from 8 populations

    DEFF Research Database (Denmark)

    Li, Yan; Thijs, Lutgarde; Hansen, Tine W

    2010-01-01

    Previous studies on the prognostic significance of the morning blood pressure surge (MS) produced inconsistent results. Using the International Database on Ambulatory Blood Pressure in Relation to Cardiovascular Outcome, we analyzed 5645 subjects (mean age: 53.0 years; 54.0% women) randomly...

  8. Inhibition of the LH surge in cyclic rats by stress is not mediated by opioids.

    NARCIS (Netherlands)

    Roozendaal, M.M.; Swarts, J.J.M.; Maanen, van J.C.; Wiegant, V.M.; Mattheij, J.A.M.

    1997-01-01

    The effects of intravenous (iv) administration of the opioid antagonists naloxone and naltrexone on the restraint-induced suppression of the pro-estrous LH surge were studied in cyclic female rats. To minimize stress during repeated blood sampling, the rats were provided with a jugular vein cannula.

  9. Predicting the Storm Surge Threat of Hurricane Sandy with the National Weather Service SLOSH Model

    Directory of Open Access Journals (Sweden)

    Cristina Forbes

    2014-05-01

    Full Text Available Numerical simulations of the storm tide that flooded the US Atlantic coastline during Hurricane Sandy (2012 are carried out using the National Weather Service (NWS Sea Lakes and Overland Surges from Hurricanes (SLOSH storm surge prediction model to quantify its ability to replicate the height, timing, evolution and extent of the water that was driven ashore by this large, destructive storm. Recent upgrades to the numerical model, including the incorporation of astronomical tides, are described and simulations with and without these upgrades are contrasted to assess their contributions to the increase in forecast accuracy. It is shown, through comprehensive verifications of SLOSH simulation results against peak water surface elevations measured at the National Oceanic and Atmospheric Administration (NOAA tide gauge stations, by storm surge sensors deployed and hundreds of high water marks collected by the U.S. Geological Survey (USGS, that the SLOSH-simulated water levels at 71% (89% of the data measurement locations have less than 20% (30% relative error. The RMS error between observed and modeled peak water levels is 0.47 m. In addition, the model’s extreme computational efficiency enables it to run large, automated ensembles of predictions in real-time to account for the high variability that can occur in tropical cyclone forecasts, thus furnishing a range of values for the predicted storm surge and inundation threat.

  10. ISSN 2073-9990 East Cent. Afr. J. surg. (Online) 76

    African Journals Online (AJOL)

    Hp 630 Dual Core

    operation1. Historically, there is a general agreement that the written history of medicine began in Egypt,. 3000 BC in the Smithss Papyrus. ... established writing and note taking as an important part of medicine. With the invention of the .... narrative operative reports in pancreatic surgery. Can J Surg Oct 2013; 56(5): E121.

  11. Efficiency and safety of percuSurge distal protection device in acute ...

    African Journals Online (AJOL)

    Acute myocardial infarction (AMI) intervention is associated with a significant incidence of slow flow or no-reflow phenomenon. PercuSurge distal protection device (DPD) has recently been approved as an effective adjunct to AMI intervention within 24 h or in the clinical settings of saphenous vein graft intervention. In this ...

  12. ISSN 2073-9990 East Cent. Afr. J. surg. (Online) 33

    African Journals Online (AJOL)

    Hp 630 Dual Core

    Afr. J. surg. (Online). Publication COSECSA/ASEA -East and Central African Journal of Surgery. August/September 2016 Volume 21 Number 2. 34 declining over the past three decades while adenocarcinoma has been progressively rising mainly due to increasing obesity and associated GERD following life style changes3, ...

  13. Climate Change Adaptation in Tokyo Bay : The Case for a Storm Surge Barrier

    NARCIS (Netherlands)

    Esteban, M.; Mikami, T.; Shibayama, T.; Takagi, H.; Jonkman, S.N.; Van Ledden, M.

    2014-01-01

    Increases in typhoon intensity and sea level rise could pose significant challenges to coastal defences around Tokyo Bay. In order to analyse the extent of future problems the authors determined the increase storm surge that could result from an increase in typhoon intensity and sea level rise to

  14. Effect of Reverse Triage on Creation of Surge Capacity in a Pediatric Hospital.

    Science.gov (United States)

    Kelen, Gabor D; Troncoso, Ruben; Trebach, Joshua; Levin, Scott; Cole, Gai; Delaney, Caitlin M; Jenkins, J Lee; Fackler, James; Sauer, Lauren

    2017-04-03

    The capacity of pediatric hospitals to provide treatment to large numbers of patients during a large-scale disaster remains a concern. Hospitals are expected to function independently for as long as 96 hours. Reverse triage (early discharge), a strategy that creates surge bed capacity while conserving resources, has been modeled for adults but not pediatric patients. To estimate the potential of reverse triage for surge capacity in an academic pediatric hospital. In this retrospective cohort study, a blocked, randomized sampling scheme was used including inpatients from 7 units during 196 mock disaster days distributed across the 1-year period from December 21, 2012, through December 20, 2013. Patients not requiring any critical interventions for 4 successive days were considered to be suitable for low-risk immediate reverse triage. Data were analyzed from November 1, 2014, through November 21, 2016. Proportionate contribution of reverse triage to the creation of surge capacity measured as a percentage of beds newly available in each unit and in aggregate. Of 3996 inpatients, 501 were sampled (268 boys [53.5%] and 233 girls [46.5%]; mean [SD] age, 7.8 [6.6] years), with 10.8% eligible for immediate low-risk reverse triage and 13.2% for discharge by 96 hours. The psychiatry unit had the most patients eligible for immediate reverse triage (72.7%; 95% CI, 59.6%-85.9%), accounting for more than half of the reverse triage effect. The oncology (1.3%; 95% CI, 0.0%-3.9%) and pediatric intensive care (0%) units had the least effect. Gross surge capacity using all strategies (routine patient discharges, full use of staffed and unstaffed licensed beds, and cancellation of elective and transfer admissions) was estimated at 57.7% (95% CI, 38.2%-80.2%) within 24 hours and 84.1% (95% CI, 63.9%-100%) by day 4. Net surge capacity, estimated by adjusting for routine emergency department admissions, was about 50% (range, 49.1%-52.6%) throughout the 96-hour period. By accepting higher

  15. Simulating storm surge inundation and damage potential within complex port facilities

    Science.gov (United States)

    Mawdsley, Robert; French, Jon; Fujiyama, Taku; Achutan, Kamalasudhan

    2017-04-01

    Storm surge inundation of port facilities can cause damage to critical elements of infrastructure, significantly disrupt port operations and cause downstream impacts on vital supply chains. A tidal surge in December 2013 in the North Sea partly flooded the Port of Immingham, which handles the largest volume of bulk cargo in the UK including major flows of coal and biomass for power generation. This flooding caused damage to port and rail transport infrastructure and disrupted operations for several weeks. This research aims to improve resilience to storm surges using hydrodynamic modelling coupled to an agent-based model of port operations. Using the December 2013 event to validate flood extent, depth and duration, we ran a high resolution hydrodynamic simulation using the open source Telemac 2D finite element code. The underlying Digital Elevation Model (DEM) was derived from Environment Agency LiDAR data, with ground truthing of the flood defences along the port frontage. Major infrastructure and buildings are explicitly resolved with varying degrees of permeability. Telemac2D simulations are run in parallel and take only minutes on a single 16 cpu compute node. Inundation characteristics predicted using Telemac 2D differ from a simple Geographical Information System 'bath-tub' analysis of the DEM based upon horizontal application of the maximum water level across the port topography. The hydrodynamic simulation predicts less extensive flooding and more closely matches observed flood extent. It also provides more precise depth and duration curves. Detailed spatial flood depth and duration maps were generated for a range of tide and surge scenarios coupled to mean sea-level rise projections. These inundation scenarios can then be integrated with critical asset databases and an agent-based model of port operation (MARS) that is capable of simulating storm surge disruption along wider supply chains. Port operators are able to act on information from a particular

  16. Optimal parameters for determining the LH surge in natural cycle frozen-thawed embryo transfers.

    Science.gov (United States)

    Irani, Mohamad; Robles, Alex; Gunnala, Vinay; Reichman, David; Rosenwaks, Zev

    2017-10-16

    There is no consensus on the exact parameters that define the LH surge for natural cycle frozen-thawed embryo transfers (NC-FET). Accurately determining the LH surge would affect the timing, and subsequently the success rates, of embryo transfer. Therefore, the aim of this study was to delineate the optimal levels and relationship for luteinizing hormone (LH) and estradiol in an effort to optimally identify the LH surge in NC-FET. It is a retrospective study that was performed in an academic medical center. Patients who underwent blastocyst NC-FET who either had preimplantation genetic screening (PGS) or were surge was defined as the first attainment of LH ≥ 17 IU/L during the follicular phase with a ≥30% drop in estradiol levels the following day; group B encompassed patients whose LH level continued to rise and the surge was defined as the highest serum LH level occurring a day after LH ≥ 17 IU/L despite a ≥ 30% drop in estradiol levels. The main outcomes measures were implantation and live birth rates. Four hundred-seven non-PGS and 284 PGS NC-FET were included. Among non-PGS cycles, group A was associated with significantly higher implantation rates (48.7% vs. 38.1%) and live birth rates (52.9% vs. 40.1%) compared to group B. In contrast, group A and B had comparable live birth rates among PGS cycles. Among non-PGS cycles, measuring LH and estradiol levels the day after an LH ≥ 17 IU/L and defining the surge as the first day of LH ≥ 17 IU/L in the context of a ≥ 30% drop in estradiol the following day was associated with better NC-FET outcomes than defining the surge as the day representing the highest serum LH level despite a ≥30% drop in estradiol levels.

  17. Strategic Engagement of Technical Surge Capacity for Intensified Polio Eradication Initiative in Nigeria, 2012–2015

    Science.gov (United States)

    Yehualashet, Yared G.; Mkanda, Pascal; Gasasira, Alex; Erbeto, Tesfaye; Onimisi, Anthony; Horton, Janet; Banda, Richard; Tegegn, Sisay G.; Ahmed, Haruna; Afolabi, Oluwole; Wadda, Alieu; Vaz, Rui G.; Nsubuga, Peter

    2016-01-01

    Background. Following the 65th World Health Assembly (WHA) resolution on intensification of the Global Poliomyelitis Eradication Initiative (GPEI), the Nigerian government, with support from the World Health Organization (WHO) and other partners, implemented a number of innovative strategies to curb the transmission of wild poliovirus (WPV) in the country. One of the innovations successfully implemented since mid 2012 is the WHO's engagement of surge capacity personnel. Methods. The WHO reorganized its functional structure, adopted a transparent recruitment and deployment process, provided focused technical and management training, and applied systematic accountability framework to successfully manage the surge capacity project in close collaboration with the national counterparts and partners. The deployment of the surge capacity personnel was guided by operational and technical requirement analysis. Results. Over 2200 personnel were engaged, of whom 92% were strategically deployed in 11 states classified as high risk on the basis of epidemiological risk analysis and compromised security. These additional personnel were directly engaged in efforts aimed at improving the performance of polio surveillance, vaccination campaigns, increased routine immunization outreach sessions, and strengthening partnership with key stakeholders at the operational level, including community-based organizations. Discussion. Programmatic interventions were sustained in states in which security was compromised and the risk of polio was high, partly owing to the presence of the surge capacity personnel, who are engaged from the local community. Since mid-2012, significant programmatic progress was registered in the areas of polio supplementary immunization activities, acute flaccid paralysis surveillance, and routine immunization with the support of the surge capacity personnel. As of 19 June 2015, the last case of WPV was reported on 24 July 2014. The surge infrastructure has

  18. Disaster metrics: quantitative benchmarking of hospital surge capacity in trauma-related multiple casualty events.

    Science.gov (United States)

    Bayram, Jamil D; Zuabi, Shawki; Subbarao, Italo

    2011-06-01

    Hospital surge capacity in multiple casualty events (MCE) is the core of hospital medical response, and an integral part of the total medical capacity of the community affected. To date, however, there has been no consensus regarding the definition or quantification of hospital surge capacity. The first objective of this study was to quantitatively benchmark the various components of hospital surge capacity pertaining to the care of critically and moderately injured patients in trauma-related MCE. The second objective was to illustrate the applications of those quantitative parameters in local, regional, national, and international disaster planning; in the distribution of patients to various hospitals by prehospital medical services; and in the decision-making process for ambulance diversion. A 2-step approach was adopted in the methodology of this study. First, an extensive literature search was performed, followed by mathematical modeling. Quantitative studies on hospital surge capacity for trauma injuries were used as the framework for our model. The North Atlantic Treaty Organization triage categories (T1-T4) were used in the modeling process for simplicity purposes. Hospital Acute Care Surge Capacity (HACSC) was defined as the maximum number of critical (T1) and moderate (T2) casualties a hospital can adequately care for per hour, after recruiting all possible additional medical assets. HACSC was modeled to be equal to the number of emergency department beds (#EDB), divided by the emergency department time (EDT); HACSC = #EDB/EDT. In trauma-related MCE, the EDT was quantitatively benchmarked to be 2.5 (hours). Because most of the critical and moderate casualties arrive at hospitals within a 6-hour period requiring admission (by definition), the hospital bed surge capacity must match the HACSC at 6 hours to ensure coordinated care, and it was mathematically benchmarked to be 18% of the staffed hospital bed capacity. Defining and quantitatively benchmarking the

  19. Oestrogen, kisspeptin, GPR54 and the pre-ovulatory luteinising hormone surge.

    Science.gov (United States)

    Clarkson, J; Herbison, A E

    2009-03-01

    Ovulation is central to mammalian fertility, yet the precise mechanism through which oestrogen triggers the gonadotrophin-releasing hormone (GnRH) surge that generates the pre-ovulatory luteinising hormone (LH) surge has remained elusive. The recent discovery that kisspeptin-GPR54 signalling is an essential regulator of the neuroendocrine axis at puberty has led investigators to evaluate the role of kisspeptin in the pre-ovulatory GnRH surge mechanism. Kisspeptin neurones are known to express oestrogen and progesterone receptors and have their cell bodies located in brain regions implicated in the positive-feedback mechanism in several mammalian species. In rodents, kisspeptin neurones located in the rostral periventricular area of the third ventricle (RP3V) are positively regulated by oestrogen and most likely are activated by oestrogen at the time of positive feedback. A similar scenario appears to exist for a sub-population of kisspeptin neurones located in the mediobasal hypothalamus of sheep and primates. The majority of GnRH neurones express GPR54, and kisspeptin causes an intense electrical activation of these cells. In concordance with this, kisspeptin administration in vivo results in an abrupt and prolonged release of LH in all mammalian species examined to date. Functional evidence from immunoneutralisation and knockout studies suggests that RP3V kisspeptin neurones projecting to GnRH neurones are an essential component of the surge mechanism in rodents. Taken together, the studies undertaken to date provide substantial evidence in support of a key role of kisspeptin-GPR54 signalling in the generation of the oestrogen-induced pre-ovulatory surge mechanism in mammals.

  20. Storm surges in the Mediterranean Sea: Variability and trends under future climatic conditions

    Science.gov (United States)

    Androulidakis, Yannis S.; Kombiadou, Katerina D.; Makris, Christos V.; Baltikas, Vassilis N.; Krestenitis, Yannis N.

    2015-09-01

    The trends of storm surge extremes in the Mediterranean Sea for a period of 150 years (1951-2100) are explored, using a high-resolution storm surge model. Numerical simulations are forced by the output of regional climate simulations with RegCM3, which uses IPCC's historical data on greenhouse gasses emissions for the (past) period 1951-2000, and IPCC's A1B climate scenario for the (future) period 2001-2100. Comparisons between observations and modeling results show good agreement and confirm the ability of our model to estimate the response of the sea surface to future climatic conditions. We investigate the future trends, the variability and frequency of local extremes and the main forcing mechanisms that can induce strong surges in the Mediterranean region. Our results support that there is a general decreasing trend in storminess under the considered climate scenario, mostly related to the frequency of local peaks and the duration and spatial coverage of the storm surges. The northward shift in the location of storm tracks is a possible reason for this storminess attenuation, especially over areas where the main driving factor of extreme events is the inverted barometer effect. However, the magnitudes of sea surface elevation extremes may increase in several Mediterranean sub-regions, i.e., Southern Adriatic, Balearic and Tyrrhenian Seas, during the 21st century. There are clear distinctions in the contributions of winds and pressure fields to the sea level height for various regions of the Mediterranean Sea, as well as on the seasonal variability of extreme values; the Aegean and Adriatic Seas are characteristic examples, where high surges are predicted to be mainly induced by low pressure systems and favorable winds, respectively.

  1. Rapid assessment tool for tropical cyclone waves and storm surge hazards in Mexico

    Science.gov (United States)

    Appendini, Christian M.; Rosengaus, Michel; Meza-Padilla, Rafael; Camacho-Magaña, Victor

    2017-04-01

    Mexico is under the constant threat of tropical cyclones generated in the Atlantic and the Eastern Pacific oceans. While the National Hurricane Center (NHC) in Miami is responsible for the forecast of tropical cyclones in both basins and providing watch and warning areas information for Mexico, Central America and the Caribbean, they are not responsible to issue waves and storm surge hazards. This work presents a quick assessment tool for waves and storm surge hazards developed under conditions that are common to developing countries: tight budget and time constraints, as well as limited numerical modeling capabilities. The system is based on 3100 synthetic tropical cyclones doing landfall in Mexico. Hydrodynamic and wave models were driven by the synthetic events to create a robust database composed of maximum envelops of wind speed, significant wave height and storm surge for each event. The results were incorporated into a forecast system that uses the NHC advisory to locate the synthetic events passing inside specified radiuses for the present and forecast position of the real event. Using limited computer resources, the system displays the information meeting the search criteria, and the forecaster can select specific events to generate the desired hazard map (i.e. wind, waves, and storm surge) based on the maximum envelop maps. This system was developed in a limited time frame to be operational in 2015 by the Hurricane and Severe Storms Unit of the Mexican National Weather Service, and represents a pilot project for other countries in the region not covered by detailed storm surge and waves forecasts.

  2. ISSN 2073-9990 East Cent. Afr. J. surg

    African Journals Online (AJOL)

    Valued eMachines Customer

    Information was given to the patients as regards the anesthetic procedures. The surgeon or the ... were discharged as soon as their post-surgical recovery allowed and all patients were instructed to do daily, routine ..... patch or prefix plug and patch in inguinal hernia: a prospective double-blind randomized controlled trial of ...

  3. ISSN 2073-9990 East Cent. Afr. J. surg. (Online)

    African Journals Online (AJOL)

    dell

    This is attributed to the association with hepatitis B, of which the presence of its surface antigen is common in these populations in up to 80% of cases1,2,3. Maiduguri is a city in the. Sahel savannah near Lake Chad in Nigeria where a previous study showed that 84.4% of controls had evidence of hepatitis B virus infection.

  4. ISSN 2073-9990 East Cent. Afr. J. surg

    African Journals Online (AJOL)

    Valued eMachines Customer

    2011-03-25

    Mar 25, 2011 ... A large amount of literature is available on the topic but it mostly describes the management of this condition in resource-rich set ... Infection control procedures were practised with use of intravenous antibiotics and blood transfusion was done with packed cells as necessary. Physiotherapy was done daily ...

  5. Surge Capacity and Capability. A review of the history and where the science is today regarding surge capacity during a mass casualty disaster.

    Directory of Open Access Journals (Sweden)

    Randy D. Kearns

    2014-04-01

    Full Text Available Disasters which include countless killed and many more injured, have occurred throughout recorded history. Many of the same reports of disaster also include numerous accounts of individuals attempting to rescue those in great peril and render aid to the injured and infirmed. The purpose of this paper is to briefly discuss the transition through several periods of time with managing a surge of many patients. This review will focus on the triggering event, injury and illness, location where the care is provided and specifically discuss where the science is today.

  6. Surge Capacity and Capability. A Review of the History and Where the Science is Today Regarding Surge Capacity during a Mass Casualty Disaster

    Science.gov (United States)

    Kearns, Randy D.; Cairns, Bruce A.; Cairns, Charles B.

    2014-01-01

    Disasters which include countless killed and many more injured, have occurred throughout recorded history. Many of the same reports of disaster also include numerous accounts of individuals attempting to rescue those in great peril and render aid to the injured and infirmed. The purpose of this paper is to briefly discuss the transition through several periods of time with managing a surge of many patients. This review will focus on the triggering event, injury and illness, location where the care is provided and specifically discuss where the science is today. PMID:24795873

  7. The Surge: General Petraeus and the Turnaround in Iraq

    Science.gov (United States)

    2010-12-01

    Iraq, the situation was grim. Increasing sectarian violence had led to an escalation of killings of civilians in Iraq, with up to 150 corpses being...found daily in Baghdad. The government of Prime Minister Nouri al- Maliki was viewed by almost everyone as ineffective at best, and the U.S. military...strategy was not well defined and clearly not working. Iraq appeared to be sliding out of control toward civil war or disintegration, and the United

  8. InSAR observations and models of crustal deformation due to a glacial surge in Iceland

    Science.gov (United States)

    Auriac, A.; Sigmundsson, F.; Hooper, A.; Spaans, K. H.; Björnsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

    2014-09-01

    Surges are common at all the major ice caps in Iceland. Ice masses of gigatons may shift from the upper part of the outlet glacier towards the terminus in a few months, advancing the glacier front by up to several kilometres. The advancing ice front may be up to 100 m thick, increasing the load on crustal rocks correspondingly. We use the observed change in crustal loading during a surge of the western part of the Vatnajökull ice cap, Iceland, during 1993-1995 and the corresponding elastic crustal deformation, surveyed with interferometric synthetic aperture radar, to investigate the material properties of the solid Earth in this region. Crustal subsidence due to the surge reaches ˜75 mm at the edge of the Síðujökull outlet glacier. This signal is mixed with a broad uplift signal of ˜12 mm yr-1, relative to our reference area, caused by the ongoing retreat of Vatnajökull in response to climate change. We disentangle the two signals by linear inversion. Finite element modelling is used to investigate the elastic Earth response of the surge, as well as to confirm that no significant viscoelastic deformation occurred as a consequence of the surge. The modelling leads to estimates of the Young's modulus and Poisson's ratio of the underlying Earth. Comparison between the observed and modelled deformation fields is made using a Bayesian approach that yields the estimate of a probability distribution for each of the free parameters. Residuals indicate a good agreement between models and observations. One-layer elastic models result in a Young's modulus of 43.2-49.7 GPa (95 per cent confidence) and Poisson's ratio of 0-0.27, after removal of outliers. Our preferred model, with two elastic layers, provides a better fit to the whole surge signal. This model consists of a 1-km-thick upper layer with an average Young's modulus of 12.9-15.3 GPa and Poisson's ratio of 0.17, overlying a layer with an average Young's modulus of 67.3-81.9 GPa and Poisson's ratio of 0.25.

  9. Influence of Northeast Monsoon cold surges on air quality in Southeast Asia

    Science.gov (United States)

    Ashfold, M. J.; Latif, M. T.; Samah, A. A.; Mead, M. I.; Harris, N. R. P.

    2017-10-01

    Ozone (O3) is an important ground-level pollutant. O3 levels and emissions of O3 precursors have increased significantly over recent decades in East Asia and export of this O3 eastward across the Pacific Ocean is well documented. Here we show that East Asian O3 is also transported southward to tropical Southeast (SE) Asia during the Northeast Monsoon (NEM) season (defined as November to February), and that this transport pathway is especially strong during 'cold surges'. Our analysis employs reanalysis data and measurements from surface sites in Peninsular Malaysia, both covering 2003-2012, along with trajectory calculations. Using a cold surge index (northerly winds at 925 hPa averaged over 105-110°E, 5°N) to define sub-seasonal strengthening of the NEM winds, we find the largest changes in a region covering much of the Indochinese Peninsula and surrounding seas. Here, the levels of O3 and another key pollutant, carbon monoxide, calculated by the Monitoring Atmospheric Composition and Climate (MACC) Reanalysis are on average elevated by, respectively, >40% (∼15 ppb) and >60% (∼80 ppb) during cold surges. Further, in the broader region of SE Asia local afternoon exceedances of the World Health Organization's air quality guideline for O3 (100 μg m-3, or ∼50 ppb, averaged over 8 h) largely occur during these cold surges. Day-to-day variations in available O3 observations at surface sites on the east coast of Peninsular Malaysia and in corresponding parts of the MACC Reanalysis are similar, and are clearly linked to cold surges. However, observed O3 levels are typically ∼10-20 ppb lower than the MACC Reanalysis. We show that these observations are also subject to influence from local urban pollution. In agreement with past work, we find year-to-year variations in cold surge activity related to the El Nino-Southern Oscillation (ENSO), but this does not appear to be the dominant influence of ENSO on atmospheric composition in this region. Overall, our study

  10. Remote-sensing-based analysis of the 1996 surge of Northern Inylchek Glacier, central Tien Shan, Kyrgyzstan

    Science.gov (United States)

    Häusler, Hermann; Ng, Felix; Kopecny, Alexander; Leber, Diethard

    2016-11-01

    The evolution of Northern Inylchek Glacier and its proglacial lake - Upper Lake Merzbacher - during its 1996 surge and the surrounding decades is analyzed with remote sensing imagery. Overall retreat of the glacier from 1943 to 1996 enlarged the lake to 4 km long and ≈ 100 m deep. The surge in 1996 initiated between 12 September and 7 October and advanced the glacier by 3.7 km to override most of Upper Lake Merzbacher. The surge phase probably ended in December 1996 and involved mean flow velocities across the lower trunk of the glacier that reached 50 m d- 1 over a 32-day period. Water displaced by the surge from Upper Lake Merzbacher, totalling 1.5 × 108 m3 in volume, accelerated filling of Lower Lake Merzbacher downvalley and helped trigger this marginal ice-dammed lake to outburst in a jökulhlaup around late November/early December. The characteristics and duration of the surge render it as similar to temperate glacier surges elsewhere. It may have been facilitated by low basal friction caused by water-saturated sediments in the upper lake bed. Furthermore, bathymetric measurements show that the surge evacuated much sediment into the upper lake, causing its depth to reduce from 20 to 30 m in 1996 to 8 m by 2005 and 2 m by 2011; the corresponding deposition rates imply glacier-catchment specific mean sediment yields of 1.4 to 3.4 × 103 Mg km- 2 a- 1 in the years after the surge. Our study documents novel interactions within a cascade system of glaciers and lakes that exhibits surging and outburst-flood behavior.

  11. Governor Design for a Hydropower Plant with an Upstream Surge Tank by GA-Based Fuzzy Reduced-Order Sliding Mode

    Directory of Open Access Journals (Sweden)

    Chang Xu

    2015-11-01

    Full Text Available This paper investigates governor design by reduced-order sliding mode for a hydropower plant with an upstream surge tank. The governing system is made up of a tunnel, a surge tank, a penstock, a wicket gate and servomechanism, a governor, a hydro-turbine and a grid. Concerning the components of the governing system, their mathematic models are established. Then, these models are interconnected to simulate the governing system. From the viewpoint of state space in modern control theory, the governing system is partially observed, which challenges the governor design. By introducing an additional state variable, the control method of reduced-order sliding mode is proposed, where the governor design is based on a reduced-order governing system. Since the governor is applied to the original governing system, the system stability is analyzed by means of the small gain theorem. An genetic algorithm is employed to search a group of parameters of the predefined sliding surface, and a fuzzy inference system is utilized to decrease the chattering problem. Some numerical simulations are illustrated to verify the feasibility and robustness of the control method.

  12. The surging role of Chromogranin A in cardiovascular homeostasis

    Directory of Open Access Journals (Sweden)

    BRUNO eTOTA

    2014-08-01

    Full Text Available Together with Chromogranin B and Secretogranins, Chromogranin A (CGA is stored in secretory (chromaffin granules of the diffuse neuroendocrine system and released with noradrenalin and adrenalin. Co-stored within the granule together with neuropeptideY, cardiac natriuretic peptide hormones, several prohormones and their proteolytic enzymes, CGA is a multifunctional protein and a major marker of the sympatho-adrenal neuroendocrine activity. Due to its partial processing to several biologically active peptides, CGA appears an important pro-hormone implicated in relevant modulatory actions on endocrine, cardiovascular, metabolic, and immune systems through both direct and indirect sympatho-adrenergic interactions. As a part of this scenario, we here illustrate the emerging role exerted by the full-length CGA and its three derived fragments, i.e. Vasostatin 1, catestatin and serpinin, in the control of circulatory homeostasis with particular emphasis on their cardio-vascular actions under both physiological and physio-pathological conditions. The Vasostatin 1- and catestatin-induced cardiodepressive influences are achieved through anti-beta-adrenergic-NO-cGMP signalling, while serpinin acts like beta1-adrenergic agonist through AD-cAMP-independent NO signalling. On the whole, these actions contribute to wide our knowledge regarding the sympatho-chromaffin control of the cardiovascular system and its highly integrated whip-brake networks.

  13. The surging role of Chromogranin A in cardiovascular homeostasis

    Science.gov (United States)

    Tota, Bruno; Angelone, Tommaso; Cerra, Maria

    2014-08-01

    Together with Chromogranin B and Secretogranins, Chromogranin A (CGA) is stored in secretory (chromaffin) granules of the diffuse neuroendocrine system and released with noradrenalin and adrenalin. Co-stored within the granule together with neuropeptideY, cardiac natriuretic peptide hormones, several prohormones and their proteolytic enzymes, CGA is a multifunctional protein and a major marker of the sympatho-adrenal neuroendocrine activity. Due to its partial processing to several biologically active peptides, CGA appears an important pro-hormone implicated in relevant modulatory actions on endocrine, cardiovascular, metabolic, and immune systems through both direct and indirect sympatho-adrenergic interactions. As a part of this scenario, we here illustrate the emerging role exerted by the full-length CGA and its three derived fragments, i.e. Vasostatin 1, catestatin and serpinin, in the control of circulatory homeostasis with particular emphasis on their cardio-vascular actions under both physiological and physio-pathological conditions. The Vasostatin 1- and catestatin-induced cardiodepressive influences are achieved through anti-beta-adrenergic-NO-cGMP signalling, while serpinin acts like beta1-adrenergic agonist through AD-cAMP-independent NO signalling. On the whole, these actions contribute to wide our knowledge regarding the sympatho-chromaffin control of the cardiovascular system and its highly integrated “whip-brake” networks.

  14. Climate Change Impacts on Flood risk in Urban Areas due to Combined Effects of Extreme Precipitation and Sea Surges

    DEFF Research Database (Denmark)

    Larsen, A. N.; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten

    Climate change will impact the hydrological cycle greatly and lead to increases in flood hazards due to both pluvial and fluvial floods as well as sea surges in many regions. The impacts of the individual effects are analysed for a catchment in Greater Copenhagen. Based on both the present...... surges. Presently the most important hazard is due to extreme precipitation. However, due to climate change impacts the future most important hazard is due to sea surges. The increase in probability of floods is substantial over a 70 year horizon and actions must be taken to decrease either the hazards...

  15. Meeting children's needs: a mixed-methods approach to a regionalized pediatric surge plan-the Los Angeles County experience.

    Science.gov (United States)

    Berg, Bridget M; Muller, Valerie M; Wilson, Millicent; Amara, Roel; Fruhwirth, Kay; Stevenson, Kathleen; Burke, Rita V; Upperman, Jeffrey S

    2014-01-01

    Children are one of the most vulnerable populations during mass casualty incidents because of their unique physiological, developmental, and psychological attributes. The objective of this project was to enhance Los Angeles County's (LAC) pediatric surge capabilities. The purpose of this study was threefold: (1) determine gaps in pediatric surge capacity and capabilities; (2) double pediatric inpatient capacity; and (3) document a plan to address gaps and meet pediatric inpatient surge. We hypothesized that LAC would be able to meet the identified pediatric surge target by leveraging resources of hospitals within the region. Deliverables included a pediatric surge plan for LAC, pediatric surge training resources, and pediatric supplies for hospitals participating in LAC's Hospital Preparedness Program (HPP). After Institutional Review Board approval, the authors used a mixed-methods approach to explore gaps in hospital capacity and capabilities in a large urban county. Hospitals were surveyed via Qualtrics® on 38 questions regarding capacity, staffing, availability of pediatric supplies, and existing pediatric surge plans. Publicly available inpatient bed data were collected from the Office of Statewide Health Planning and Development for the year ending June 2010 and supplemented by hospital survey responses. Population data was used from US Census 2010. This combined dataset was analyzed for capacity, pediatric designations, and capabilities. To supplement this data, three focus groups were conducted between April 2011 and May 2012. Focus group topics included: supplies and training needed for pediatric surge, surge targets, and plan development and functionality. Hospitals varied in pediatric capacity and capability. Forty-six percent of facilities provide inpatient pediatric services. Forty-one hospitals are designated as an Emergency Department Approved for Pediatrics. Identified gaps included: limited pediatric bed capacity, geographic variability, limited

  16. Surge and swab pressures in wells with cross-section changes; Pressoes de surge and swab em pocos com variacao de secao

    Energy Technology Data Exchange (ETDEWEB)

    Fedevjcyk, Joao Victor; Junqueira, Silvio Luiz de Mello; Negrao, Cezar Otaviano Ribeiro [Universidade Tecnologica Federal do Parana (UTFPR). Laboratorio de Ciencias Termicas (Lacit) (Brazil)], e-mails: silvio@utfpr.edu.br, negrao@utfpr.edu.br

    2009-12-15

    Well drilling is performed by rotating and applying a weighted drill bit to the geological formation. Well diameter variations and the use of drill pipe accessories might cause changes to the annular cross section space between the drill pipe and the borehole. It should be noted cross section changes influence pressure losses within the well. This study proposes a mathematical/ numerical model to simulate the surge and swab problem in wells with variable cross section areas. The fluid flow yielded by the drill pipe motion is considered to be one-dimensional, isothermal, compressible and transient. The proposed model features the mass and momentum conservation equations, along with a state equation and a constitutive equation for Bingham or Power Law fluids. The governing equations were discretized by the Finite Volume Method. The well is assumed to be impermeable and the drill pipe end to be closed. The results were compared to measured data obtained at the Taquipe experimental well with good agreement. Predictions can now be made as to how changes in cross section areas may significantly affect the transient surge and swab pressures. (author)

  17. High Serum Level of Matrix Metalloproteinase-1 and Its Rapid Surge After Intervention in Patients with Significant Carotid Atherosclerosis

    Directory of Open Access Journals (Sweden)

    Yen-Wen Wu

    2008-01-01

    Full Text Available High tissue matrix metalloproteinase (MMP activity has been reported to be associated with atherosclerosis and plaque rupture. The aim of this study was to elucidate the diagnostic value of serum MMP-1 in carotid stenosis and its dynamic change after stenting. We measured high-sensitivity C-reactive protein (hs-CRP and MMP-1 in 37 patients with carotid stenosis (≥ 50% and 84 controls. In 30 patients who underwent stenting, MMP-1 and hs-CRP were assessed immediately after stenting. We found that patients with carotid stenosis exhibited significantly higher MMP-1 compared with controls, but there was no difference in hs-CRP. Moreover, MMP-1 was elevated immediately after stenting. In multivariate analyses, MMP-1 was negatively correlated with statin and angiotensin converting enzyme inhibitor/angiotensin-II receptor blocker use in controls. In conclusion, higher levels and rapid surge after stenting in patients with carotid stenosis indicate that MMP-1 is an important composition of plaques, and suggest its potential role in the assessment of plaque burden and stability of carotid stenosis.

  18. Mathematical modeling of the GnRH pulse and surge generator

    CERN Document Server

    Clement, Frederique

    2007-01-01

    We propose a mathematical model allowing for the alternating pulse and surge pattern of GnRH (Gonadotropin Releasing Hormone) secretion. The model is based on the coupling between two systems running on different time scales. The faster system corresponds to the average activity of GnRH neurons, while the slower one corresponds to the average activity of regulatory neurons. The analysis of the slow/fast dynamics exhibited within and between both systems allows to explain the different patterns (slow oscillations, fast oscillations and periodical surge) of GnRH secretion. Specifications on the model parameter values are derived from physiological knowledge in terms of amplitude, frequency and plateau length of oscillations. The behavior of the model is finally illustrated by numerical simulations reproducing natural ovarian cycles and either direct or indirect actions of ovarian steroids on GnRH secretion.

  19. Improving Short-Range Ensemble Kalman Storm Surge Forecasting Using Robust Adaptive Inflation

    KAUST Repository

    Altaf, Muhammad

    2013-08-01

    This paper presents a robust ensemble filtering methodology for storm surge forecasting based on the singular evolutive interpolated Kalman (SEIK) filter, which has been implemented in the framework of the H∞ filter. By design, an H∞ filter is more robust than the common Kalman filter in the sense that the estimation error in the H∞ filter has, in general, a finite growth rate with respect to the uncertainties in assimilation. The computational hydrodynamical model used in this study is the Advanced Circulation (ADCIRC) model. The authors assimilate data obtained from Hurricanes Katrina and Ike as test cases. The results clearly show that the H∞-based SEIK filter provides more accurate short-range forecasts of storm surge compared to recently reported data assimilation results resulting from the standard SEIK filter.

  20. Mangroves as a protection from storm surges in a changing climate.

    Science.gov (United States)

    Blankespoor, Brian; Dasgupta, Susmita; Lange, Glenn-Marie

    2017-05-01

    Adaptation to climate change includes addressing sea-level rise (SLR) and increased storm surges in many coastal areas. Mangroves can substantially reduce vulnerability of the adjacent coastal land from inundation but SLR poses a threat to the future of mangroves. This paper quantifies coastal protection services of mangroves for 42 developing countries in the current climate, and a future climate change scenario with a 1-m SLR and 10  % intensification of storms. Findings demonstrate that while SLR and increased storm intensity would increase storm surge areas, the greatest impact is from the expected loss of mangroves. Under current climate and mangrove coverage, 3.5 million people and GDP worth roughly US $400 million are at risk. In the future climate change scenario, vulnerable population and GDP at risk would increase by 103 and 233  %. The greatest risk is in East Asia, especially in Indonesia and the Philippines as well as Myanmar.

  1. AN ULTRASONIC PHASED ARRAY EVALUATION OF CAST AUSTENITIC STAINLESS STEEL PRESSURIZER SURGE LINE PIPING WELDS

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Aaron A.; Cinson, Anthony D.; Crawford, Susan L.; Moran, Traci L.; Anderson, Michael T.

    2010-07-22

    A set of circumferentially oriented thermal fatigue cracks (TFCs) were implanted into three cast austenitic stainless steel (CASS) pressurizer (PZR) surge-line specimens (pipe-to-elbow welds) that were fabricated using vintage CASS materials formed in the 1970s, and flaw responses from these cracks were used to evaluate detection and sizing performance of the phased-array (PA) ultrasonic testing (UT) methods applied. Four different custom-made PA probes were employed in this study, operating nominally at 800 kHz, 1.0 MHz, 1.5 MHz, and 2.0 MHz center frequencies. The CASS PZR surge-line specimens were polished and chemically etched to bring out the microstructures of both pipe and elbow segments. Additional studies were conducted and documented to address baseline CASS material noise and observe possible ultrasonic beam redirection phenomena.

  2. Application of Powell's optimization method to surge arrester circuit models' parameters

    Energy Technology Data Exchange (ETDEWEB)

    Christodoulou, C.A.; Stathopulos, I.A. [National Technical University of Athens, School of Electrical and Computer Engineering, 9 Iroon Politechniou St., Zografou Campus, 157 80 Athens (Greece); Vita, V.; Ekonomou, L.; Chatzarakis, G.E. [A.S.PE.T.E. - School of Pedagogical and Technological Education, Department of Electrical Engineering Educators, N. Heraklion, 141 21 Athens (Greece)

    2010-08-15

    Powell's optimization method has been used for the evaluation of the surge arrester models parameters. The proper modelling of metal-oxide surge arresters and the right selection of equivalent circuit parameters are very significant issues, since quality and reliability of lightning performance studies can be improved with the more efficient representation of the arresters' dynamic behavior. The proposed approach selects optimum arrester model equivalent circuit parameter values, minimizing the error between the simulated peak residual voltage value and this given by the manufacturer. Application of the method in performed on a 120 kV metal oxide arrester. The use of the obtained optimum parameter values reduces significantly the relative error between the simulated and manufacturer's peak residual voltage value, presenting the effectiveness of the method. (author)

  3. Storm Surge Risk Assessment of Tacloban, Leyte Using MIKE 21 Model Simulation of Typhoon Haiyan

    Science.gov (United States)

    Prelligera, F. A.; Ladiero, C.; Caro, C. V.; Lagmay, A. M. F. A.; Lapidez, J. P. B.; Suarez, J. K. B.; Santiago, J. T.; Agaton, R.

    2014-12-01

    Rehabilitation efforts for the destruction of Typhoon Haiyan which ravaged the central part of the Philippines may take up to 10 years and will cost PhP 250 billion (USD 5.7 billion). To prevent extensive damages and extreme cost for rehabilitation, thorough risk assessment along with systematic infrastructure plans, evacuation plans, and land use planning of the areas must be done. The study conducted a qualitative risk assessment for the city of Tacloban, one of the severely affected areas by the storm surges brought about by the typhoon. Its coastal areas are at high risk to storm surge due to: its location relative to the typhoon track; low elevation topography; dense population; and progressive economic activities. The risk assessment model proposed by the United Nations (1991) was used, where the risk index is defined by the hazard index multiplied by its vulnerability index. The risk index was evaluated into a five-point scale: very high, high, medium, low, very low. The storm surge hazard index of the study area was derived from the simulation results of Typhoon Haiyan event using MIKE 21 - a versatile software used for coastal modelling. Simulations were made using the coupled approach of Hydrodynamic Flexible Mesh (HD FM) and Spectral Wave (SW) models. This approach takes into account both surge water levels and wave crest heights for overtopping of coastal structures. The vulnerability index was determined from population, built environment, and critical service centers. The resulting risk index map will be beneficial to the on-going rehabilitation efforts in the study area.

  4. The Climatology of Extreme Surge-Producing Extratropical Cyclones in Observations and Models

    Science.gov (United States)

    Catalano, A. J.; Broccoli, A. J.; Kapnick, S. B.

    2016-12-01

    Extreme coastal storms devastate heavily populated areas around the world by producing powerful winds that can create a large storm surge. Both tropical and extratropical cyclones (ETCs) occur over the northwestern Atlantic Ocean, and the risks associated with ETCs can be just as severe as those associated with tropical storms (e.g. high winds, storm surge). At The Battery in New York City, 17 of the 20 largest storm surge events were a consequence of extratropical cyclones (ETCs), which are more prevalent than tropical cyclones in the northeast region of the United States. Therefore, we analyze the climatology of ETCs that are capable of producing a large storm surge along the northeastern coast of the United States. For a historical analysis, water level data was collected from National Oceanic and Atmospheric Administration (NOAA) tide gauges at three separate locations (Sewell's Pt., VA, The Battery, NY, and Boston, MA). We perform a k-means cluster analysis of sea level pressure from the ECMWF 20th Century Reanalysis dataset (ERA-20c) to explore the natural sets of observed storms with similar characteristics. We then composite cluster results with features of atmospheric circulation to observe the influence of interannual and multidecadal variability such as the North Atlantic Oscillation. Since observational records contain a small number of well-documented ETCs, the capability of a high-resolution coupled climate model to realistically simulate such extreme coastal storms will also be assessed. Global climate models provide a means of simulating a much larger sample of extreme events, allowing for better resolution of the tail of the distribution. We employ a tracking algorithm to identify ETCs in a multi-century simulation under present-day conditions. Quantitative comparisons of cyclolysis, cyclogenesis, and cyclone densities of simulated ETCs and storms from recent history (using reanalysis products) are conducted.

  5. Storm surge modeling of Superstorm Sandy in the New York City Metropolitan area

    Science.gov (United States)

    Benimoff, A. I.; Blanton, B. O.; Dzedzits, E.; Fritz, W. J.; Kress, M.; Muzio, P.; Sela, L.

    2013-12-01

    Even though the New York/New Jersey area does not lie within the typical 'hurricane belt', recent events and the historical record indicate that large infrequent tropical storms have had direct hits on the region, with impacts being amplified due to the nearly right angle bend in the coastline. The recent plan unveiled by New York City's Mayor Bloomberg lays out mitigation strategies to protect the region's communities, infrastructure, and assets from future storms, and numerical simulation of storm surge and wave hazards driven by potential hurricanes plays a central role in developing and evaluating these strategies. To assist in local planning, recovery, and decision-making, we have used the tide, storm surge, and wind wave model ADCIRC+SWAN to simulate storm surge in one of the most populated areas of the United States: the New York City (NYC) metropolitan area. We have generated a new high-resolution triangular finite-element model grid for the region from recent USGS data as well as recent city topographic maps at 2-foot (0.6m) contour intervals, nautical charts, and details of shipping channels. Our hindcast simulations are compared against Superstorm Sandy. We used the City University of New York High Performance Computing Center's Cray XE6tm at the College of Staten Island for these simulations. Hindcasting and analysis of the Superstorm Sandy storm surge and waves indicates that our simulations produce a reasonable representation of actual events. The grid will be used in an ADCIRC-based forecasting system implementation for the region.

  6. Uncertainty and feasibility of dynamical downscaling for modeling tropical cyclones for storm surge simulation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaoqing; Taraphdar, Sourav; Wang, Taiping; Ruby Leung, L.; Grear, Molly

    2016-08-22

    This paper presents a modeling study conducted to evaluate the uncertainty of a regional model in simulating hurricane wind and pressure fields, and the feasibility of driving coastal storm surge simulation using an ensemble of region model outputs produced by 18 combinations of three convection schemes and six microphysics parameterizations, using Hurricane Katrina as a test case. Simulated wind and pressure fields were compared to observed H*Wind data for Hurricane Katrina and simulated storm surge was compared to observed high-water marks on the northern coast of the Gulf of Mexico. The ensemble modeling analysis demonstrated that the regional model was able to reproduce the characteristics of Hurricane Katrina with reasonable accuracy and can be used to drive the coastal ocean model for simulating coastal storm surge. Results indicated that the regional model is sensitive to both convection and microphysics parameterizations that simulate moist processes closely linked to the tropical cyclone dynamics that influence hurricane development and intensification. The Zhang and McFarlane (ZM) convection scheme and the Lim and Hong (WDM6) microphysics parameterization are the most skillful in simulating Hurricane Katrina maximum wind speed and central pressure, among the three convection and the six microphysics parameterizations. Error statistics of simulated maximum water levels were calculated for a baseline simulation with H*Wind forcing and the 18 ensemble simulations driven by the regional model outputs. The storm surge model produced the overall best results in simulating the maximum water levels using wind and pressure fields generated with the ZM convection scheme and the WDM6 microphysics parameterization.

  7. Possibility Of Generating Significant Storm Surge On The Western Seaboard Of Metro Manila, Philippines

    Science.gov (United States)

    Suarez, J. K. B.; Santiago, J. T.; Tablazon, J. P.; Dasallas, L. L.; Goting, P. G.; Lagmay, A. M. A.

    2016-12-01

    The Philippines, located in the Northwestern Pacific Typhoon gateway to Asia, is considered one of the most susceptible to tropical cyclone related hazards. One of the most disastrous effects of tropical cyclones is storm surge. With Metro Manila being a coastal area and the most populous region in the country, with approximately 12.8 million people residing in it, it is of great interest to determine the possibility of generating significant level of storm surge in the country's capital. The necessity to determine the storm surge susceptibility was brought upon by the effect of Typhoon Haiyan on eastern Visayas in 2013, where more than 6,000 people died and resulted to about 2.86 billion dollars' worth of damages. To achieve the objectives, the actual tracks and wind speed of historical typhoon (JMA data since 1951) was mapped for the Philippines. The simulated wind speed map shows that the maximum winds are mostly experienced on the eastern side of the country; with a considerable decrease in wind intensity as the typhoon reaches the western seaboard due to land surface. The Haiyan-strength wind speed is then applied to the actual historical typhoon tracks to determine the hypothetical values of wind speed as a typhoon with Haiyan intensity reached Metro Manila. Results show that, if a typhoon with a Haiyan-like intensity is to traverse tracks like those of Rita 1978, Collen 1992, Sybil 1995, Bebinca 2000 and Xangsane 2000, there is a huge possibility of generating storm surge height of 3.9 to 5.6 m in the western seaboard of Metro Manila, even after considering the diminishing effect of surface friction.

  8. Parameters Optimization for Operational Storm Surge/Tide Forecast Model using a Genetic Algorithm

    Science.gov (United States)

    Lee, W.; You, S.; Ryoo, S.; Global Environment System Research Laboratory

    2010-12-01

    Typhoons generated in northwestern Pacific Ocean annually affect the Korean Peninsula and storm surges generated by strong low pressure and sea winds often cause serious damage to property in the coastal region. To predict storm surges, a lot of researches have been conducted by using numerical models for many years. Various parameters used for calculation of physics process are used in numerical models based on laws of physics, but they are not accurate values. Because those parameters affect to the model performance, these uncertain values can sensitively operate results of the model. Therefore, optimization of these parameters used in numerical model is essential for accurate storm surge predictions. A genetic algorithm (GA) is recently used to estimate optimized values of these parameters. The GA is a stochastic exploration modeling natural phenomenon named genetic heritance and competition for survival. To realize breeding of species and selection, the groups which may be harmed are kept and use genetic operators such as inheritance, mutation, selection and crossover. In this study, we have improved operational storm surge/tide forecast model(STORM) of NIMR/KMA (National Institute of Meteorological Research/Korea Meteorological Administration) that covers 115E - 150E, 20N - 52N based on POM (Princeton Ocean Model) with 8km horizontal resolutions using the GA. Optimized values have been estimated about main 4 parameters which are bottom drag coefficient, background horizontal diffusivity coefficient, Smagoranski’s horizontal viscosity coefficient and sea level pressure scaling coefficient within STORM. These optimized parameters were estimated on typhoon MAEMI in 2003 and 9 typhoons which have affected to Korea peninsula from 2005 to 2007. The 4 estimated parameters were also used to compare one-month predictions in February and August 2008. During the 48h forecast time, the mean and median model accuracies improved by 25 and 51%, respectively.

  9. Development and validation of a surgical workload measure: the surgery task load index (SURG-TLX).

    Science.gov (United States)

    Wilson, Mark R; Poolton, Jamie M; Malhotra, Neha; Ngo, Karen; Bright, Elizabeth; Masters, Rich S W

    2011-09-01

    The purpose of the present study was to develop and validate a multidimensional, surgery-specific workload measure (the SURG-TLX), and to determine its utility in providing diagnostic information about the impact of various sources of stress on the perceived demands of trained surgical operators. As a wide range of stressors have been identified for surgeons in the operating room, the current approach of considering stress as a unidimensional construct may not only limit the degree to which underlying mechanisms may be understood but also the degree to which training interventions may be successfully matched to particular sources of stress. The dimensions of the SURG-TLX were based on two current multidimensional workload measures and developed via focus group discussion. The six dimensions were defined as mental demands, physical demands, temporal demands, task complexity, situational stress, and distractions. Thirty novices were trained on the Fundamentals of Laparoscopic Surgery (FLS) peg transfer task and then completed the task under various conditions designed to manipulate the degree and source of stress experienced: task novelty, physical fatigue, time pressure, evaluation apprehension, multitasking, and distraction. The results were supportive of the discriminant sensitivity of the SURG-TLX to different sources of stress. The sub-factors loaded on the relevant stressors as hypothesized, although the evaluation pressure manipulation was not strong enough to cause a significant rise in situational stress. The present study provides support for the validity of the SURG-TLX instrument and also highlights the importance of considering how different stressors may load surgeons. Implications for categorizing the difficulty of certain procedures, the implementation of new technology in the operating room (man-machine interface issues), and the targeting of stress training strategies to the sources of demand are discussed. Modifications to the scale to enhance

  10. ISSN 2073-9990 East Cent. Afr. J. surg. (Online) 60

    African Journals Online (AJOL)

    Hp 630 Dual Core

    G.P. Hadley, R. Wiersma Membranous atresia of the intra abdominal esophagus: a case report S Afr Med J, 77 (1990), pp. 210 211. 6. Pai GK1, Pai PK, Kini AU, Rao J. Membranous type of esophageal atresia at the cardiac end of the esophagus: a case report.Pediatr Surg. 1987 Nov;22(11):986 7. 7. Matsumoto Y, Ogawa K ...

  11. Bridging complexity theory and resilience to develop surge capacity in health systems.

    Science.gov (United States)

    Therrien, Marie-Christine; Normandin, Julie-Maude; Denis, Jean-Louis

    2017-03-20

    Purpose Health systems are periodically confronted by crises - think of Severe Acute Respiratory Syndrome, H1N1, and Ebola - during which they are called upon to manage exceptional situations without interrupting essential services to the population. The ability to accomplish this dual mandate is at the heart of resilience strategies, which in healthcare systems involve developing surge capacity to manage a sudden influx of patients. The paper aims to discuss these issues. Design/methodology/approach This paper relates insights from resilience research to the four "S" of surge capacity (staff, stuff, structures and systems) and proposes a framework based on complexity theory to better understand and assess resilience factors that enable the development of surge capacity in complex health systems. Findings Detailed and dynamic complexities manifest in different challenges during a crisis. Resilience factors are classified according to these types of complexity and along their temporal dimensions: proactive factors that improve preparedness to confront both usual and exceptional requirements, and passive factors that enable response to unexpected demands as they arise during a crisis. The framework is completed by further categorizing resilience factors according to their stabilizing or destabilizing impact, drawing on feedback processes described in complexity theory. Favorable order resilience factors create consistency and act as stabilizing forces in systems, while favorable disorder factors such as diversity and complementarity act as destabilizing forces. Originality/value The framework suggests a balanced and innovative process to integrate these factors in a pragmatic approach built around the fours "S" of surge capacity to increase health system resilience.

  12. Cost benefit analysis of high surge impedance loading (HSIL) HVAC transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Dariani, A.; Kumar, K. [SNC Lavalin Transmission and Distribution, Calgary, AB (Canada)

    2008-07-01

    The amount of power that a given extra high voltage alternating current transmission line can safely carry depends on different thermal and stability/surge impedance loading (SIL) limits. In the case of long lines, the capacity is limited by its SIL level only, which is much below its thermal capacity due to large inductance. Decrease in line inductance and surge impedance increases the SIL and transmission capacity. However, ever increasing demand for electrical energy along with stringent environmental constraints and deregulation of electricity market, have forced the utility companies to consider using compact and high throughput transmission lines in a narrower corridors. Compact transmission lines have lower surge impedance and higher power transfer capability but suffer from higher tower cost, as well as system operational constraints. This paper examined the sensitivity of incremental transmission line cost to the degree of tower compacting and attainable power transfer capability, considering the operational constraints, and other environmental issues such as electromagnetic field effects at the edge of the associated right of way. A set of 31 single and double circuit 500KV tower outlines were considered for analysis. A normalized line surge impedance loading and associated costs were considered for each case. The costs included land easement, foundation, hardware, conductors, engineering and installation. The paper described the methodology for optimizing each configuration based on the functionality, maintainability, capital cost and other parameters for tower selection. It was concluded that the analysis should be extended to include other techniques for increasing power transfer capacity. 5 refs., 1 tab., 4 figs.

  13. Human survival in volcanic eruptions: Thermal injuries in pyroclastic surges, their causes, prognosis and emergency management.

    Science.gov (United States)

    Baxter, Peter J; Jenkins, Susanna; Seswandhana, Rosadi; Komorowski, Jean-Christophe; Dunn, Ken; Purser, David; Voight, Barry; Shelley, Ian

    2017-08-01

    This study of burns patients from two eruptions of Merapi volcano, Java, in 1994 and 2010, is the first detailed analysis to be reported of thermal injuries in a large series of hospitalised victims of pyroclastic surges, one of the most devastating phenomena in explosive eruptions. Emergency planners in volcanic crises in populated areas have to integrate the health sector into disaster management and be aware of the nature of the surge impacts and the types of burns victims to be expected in a worst scenario, potentially in numbers and in severity that would overwhelm normal treatment facilities. In our series, 106 patients from the two eruptions were treated in the same major hospital in Yogyakarta and a third of these survived. Seventy-eight per cent were admitted with over 40% TBSA (total body surface area) burns and around 80% of patients were suspected of having at least some degree of inhalation injury as well. Thirty five patients suffered over 80% TBSA burns and only one of these survived. Crucially, 45% of patients were in the 40-79% TBSA range, with most suspected of suffering from inhalation injury, for whom survival was most dependent on the hospital treatment they received. After reviewing the evidence from recent major eruptions and outlining the thermal hazards of surges, we relate the type and severity of the injuries of these patients to the temperatures and dynamics of the pyroclastic surges, as derived from the environmental impacts and associated eruption processes evaluated in our field surveys and interviews conducted by our multi-disciplinary team. Effective warnings, adequate evacuation measures, and political will are all essential in volcanic crises in populated areas to prevent future catastrophes on this scale. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  14. Into the Surge of Network-driven Innovation:Extending the Historical Framing of Innovation

    OpenAIRE

    Østergaard, Claus Møller; Rosenstand, Claus Andreas Foss; Gertsen, Frank; Lervang, Johan-Ulrik

    2013-01-01

    The ambition of this paper is to provide a better theoretical understanding of innovation by framing it in a long historical, economical, and societal perspective. The research question of the paper is: What characterize the historical surges of innovation? Based on previous works and research this is examined from the 1880’s up until today. The contribution of the paper is a societal perspective on innovation, where the difference between industrial society and knowledge society leads into t...

  15. A Tsunami Ball Approach to Storm Surge and Inundation: Application to Hurricane Katrina, 2005

    Directory of Open Access Journals (Sweden)

    Steven N. Ward

    2009-01-01

    Full Text Available Most analyses of storm surge and inundation solve equations of continuity and momentum on fixed finite-difference/finite-element meshes. I develop a completely new approach that uses a momentum equation to accelerate bits or balls of water over variable depth topography. The thickness of the water column at any point equals the volume density of balls there. In addition to being more intuitive than traditional methods, the tsunami ball approach has several advantages. (a By tracking water balls of fixed volume, the continuity equation is satisfied automatically and the advection term in the momentum equation becomes unnecessary. (b The procedure is meshless in the finite-difference/finite-element sense. (c Tsunami balls care little if they find themselves in the ocean or inundating land. (d Tsunami ball calculations of storm surge can be done on a laptop computer. I demonstrate and calibrate the method by simulating storm surge and inundation around New Orleans, Louisiana caused by Hurricane Katrina in 2005 and by comparing model predictions with field observations. To illustrate the flexibility of the tsunami ball technique, I run two “What If” hurricane scenarios—Katrina over Savannah, Georgia and Katrina over Cape Cod, Massachusetts.

  16. A hybrid DEM-SPH model for deformable landslide and its generated surge waves

    Science.gov (United States)

    Tan, Hai; Chen, Shenghong

    2017-10-01

    Reservoir bank landslide and its generated surge waves are catastrophic hazards which may give rise to additional sedimentation, destroy hydraulic structures, and even cause fatalities. Since this process is very complex involving landslide impact, wave generation and propagation, it cannot be well captured with traditional numerical approaches. In this paper, a hybrid DEM-SPH model is presented to simulate landslide and to reproduce its generated surge waves. This model consists of discrete element method (DEM) for solid phase and smoothed particle hydrodynamics (SPH) for fluid phase as well as drag force and buoyancy for solid-fluid interaction. Meanwhile, the δ-SPH algorithm is employed to eliminate spurious numerical noise on the pressure field. Submarine rigid block slide is numerically tested to validate the proposed hybrid model, and the computed wave profiles exhibit a satisfactory agreement with the experiment. The hybrid model is further extended towards the submarine granular deformable slide which generates smaller and less violent surge waves. Kinetic and potential energy of both solid and fluid particle system are extracted to throw a light upon the process of landslide water interaction from an energy perspective. Finally, a sensitivity analysis on particle friction coefficient indicates that the lubrication of the solid particles is another important effect influencing the underwater landslide movement in addition to the drag effect.

  17. Milk Leptin Surge and Biological Rhythms of Leptin and Other Regulatory Proteins in Breastmilk.

    Science.gov (United States)

    Nozhenko, Yuriy; Asnani-Kishnani, Madhu; Rodríguez, Ana M; Palou, Andreu

    2015-01-01

    A significant number of chronic diseases are linked to perinatal nutrition, and prevention may be associated to naturally occurring components of breast milk. One key hormone in breast milk is leptin, related with the protection from obesity in the adulthood, thus knowing its changes through the day or lactation is crucial. We aimed to investigate the daily rhythms in the milk levels of leptin, together with other two related hormones, ghrelin and adiponectin, during lactation (days 5, 10 and 15) in rat dams, and the relation with morphometric parameters (dams and pups). Summarizing the main results, the existence of biological rhythms, but not daily and maybe circasemidian, was confirmed for the three hormones at the earliest period of lactation. The correlations performed generally showed a possible dependence of milk hormone levels on plasma levels at the early phase of lactation, while with the progression of lactation this dependence may fade and the hormone levels are suggested to be more dependent on mammary gland production/maturation. There was also a correlation between milk leptin and adiponectin levels, especially in the first half of lactation, suggesting a possible parallel regulation. Interestingly, we describe a milk leptin surge around the mid of lactation (at day 10) which may be related with pup's growth (males and females) and with the well-known (in the literature) plasma leptin surge in pups. All this knowledge may be crucial for future applications in the development of formula milk and in relation with the role of leptin surge during lactation.

  18. Hurricane-induced waves and storm surge modeling for the Mexican coast

    Science.gov (United States)

    Meza-Padilla, Rafael; Appendini, Christian M.; Pedrozo-Acuña, Adrián

    2015-08-01

    This paper describes the application of a third-generation wave model and a hydrodynamic model to determine extreme waves and water levels associated to the incidence of tropical cyclones along the Mexican coast. In addition to historical records and to overcome the limitation associated to data scarcity in Mexico, we employ information from 3100 synthetic events generated from a statistical/deterministic hurricane model. This enables the generation of a more robust database for the characterization of extreme water levels along the Mexican coast. The procedure incorporates a storm track modeling approach where, for each hurricane (historic and synthetic), the entire track is numerically reproduced as it crosses the ocean and makes landfall. Extreme values for both, waves and storm surge, are determined through an extreme value analysis at each mesh element, allowing for the identification of their spatial variability. Results for the Gulf of Mexico show that highest waves are expected along both the Caribbean Sea and the northern coast of the Gulf of Mexico, while extreme water levels due to storm surge are identified in the northern part of the Yucatan Peninsula. On the other hand, along the Pacific coast, extreme values for waves are identified at the central mainland Mexico while storm surge is minimal. The methodology is proved to be a good alternative in the reproduction of continuously varying tropical cyclone climatology along the Mexican coastline, and it provides a rational approach for assessing the hurricane-induced risk in coastal areas.

  19. Development of thermal runaway preventing ZnO varistor for surge protective device.

    Science.gov (United States)

    Jeoung, Tae-Hoon; Kim, Young-Sung; Nam, Sung-Pill; Lee, Seung-Hwan; Kang, Jeong-Wook; Kim, Jea-Chul; Lee, Sung-Gap

    2014-12-01

    In this paper, the centre of electrode is suggested for heat conduction. Therefore, the specific reflow soldering process is needed. The comparison of temperature difference among the different areas of ZnO varistors is analyzed. With the nominal surge current, thermal behavior is analyzed. The operation point of temperature for disconnection is proposed. Accordingly, the thermal runaway-preventing ZnO varistors were covered with a fusible alloy, i.e., a thermal fuse, in the process of manufacture, which is expected to ensure there the liability of being resistant to lightning discharge and to ensure stability against thermal runaway in the failure mode. Additionally, it is expected to reduce much more limit voltage than the existing products to which the fuse was separately applied. The thermal runaway-preventing ZnO varistor of the surge protection devices can be widely used as part of the protection provisions of lightning discharge and surge protection demanded in connection with power IT about Green Growth which is nowadays becoming the buzzword in the electric power industry.

  20. Blowout Surge due to Interaction between a Solar Filament and Coronal Loops

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haidong; Jiang, Yunchun; Yang, Jiayan; Yang, Bo; Xu, Zhe; Bi, Yi; Hong, Junchao; Chen, Hechao [Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216 (China); Qu, Zhining, E-mail: lhd@ynao.ac.cn [Department of Physics, School of Science, Sichuan University of Science and Engineering, Zigong 643000 (China)

    2017-06-20

    We present an observation of the interaction between a filament and the outer spine-like loops that produces a blowout surge within one footpoint of large-scale coronal loops on 2015 February 6. Based the observation of the AIA 304 and 94 Å, the activated filament is initially embedded below a dome of a fan-spine configuration. Due to the ascending motion, the erupting filament reconnects with the outer spine-like field. We note that the material in the filament blows out along the outer spine-like field to form the surge with a wider spire, and a two-ribbon flare appears at the site of the filament eruption. In this process, small bright blobs appear at the interaction region and stream up along the outer spine-like field and down along the eastern fan-like field. As a result, a leg of the filament becomes radial and the material in it erupts, while another leg forms the new closed loops. Our results confirm that the successive reconnection occurring between the erupting filament and the coronal loops may lead to a strong thermal/magnetic pressure imbalance, resulting in a blowout surge.

  1. Development of a storm surge driven water quality model to simulate spills during hurricanes.

    Science.gov (United States)

    Kiaghadi, Amin; Rifai, Hanadi S; Burleson, Daniel W

    2017-11-02

    Hurricanes can cause widespread environmental pollution that has yet to be fully articulated. This study develops a predictive water quality model to forecast potential contamination resulting from buckled or ruptured storage tanks in coastal industrialized areas when subjected to storm surge. The developed EFDC-Storm Surge model (EFDC-SS) couples EPA's EFDC code with the SWAN-ADCIRC hurricane simulation model. EFDC-SS is demonstrated using the Houston Ship Channel in Texas as a testbed and hurricane Ike as a model hurricane. Conservative and decaying dye runs evaluated various hurricane scenarios, combined with spills released at different locations and release times. Results showed that tank locations with shorter distances to the main waterbody and lower ground elevations have a higher risk of inundation and rapid spill mass transport. It was also determined that hurricane strength and landfall location, the location of the spill, and the spill release time relative to peak surge were interdependent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Estimating medically fragile population in storm surge zones: a geographic information system application.

    Science.gov (United States)

    Wilson, James L; Little, Ruth; Novick, Lloyd

    2013-01-01

    To develop a simple, cost-effective method for determining the size and geographic distribution of medically fragile (MF) individuals at risk from tropical storm surges for use by emergency management planners. The study used Geographic Information System (GIS) spatially referenced layers based on secondary data sources from both state and federal levels. The study setting included the eastern North Carolina coastal counties that would be affected by tropical storm surges. The initial MF population was extrapolated from national estimates for five conditions and then applied to US Census block population. These conditions included insulin dependent diabetes, chronic obstructive pulmonary disease, congestive heart failure, end stage renal disease, and patients receiving long-term oxygen treatment. The main outcome of this study was a series of local and regional maps that portrayed the geographic distribution and estimated counts of potentially at-risk MF population from a tropical storm surge scenario. Maps depicting the geographic distribution and potential numbers of MF individuals are important information for planning and preparedness in emergency management and potentially engaging the public.

  3. Development and validation of the pressure surge computer code DYVRO mod. 3

    Energy Technology Data Exchange (ETDEWEB)

    Neuhaus, T.; Schaffrath, A. [TUEV NORD Systec GmbH und Co. KG, Hamburg (Germany); Altstadt, E. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (DE). Inst. fuer Sicherheitsforschung (IFS)

    2008-11-15

    Pressure fluctuations are generated in pipeline systems, when a fluid is rapidly accelerated or decelerated by fast closing or opening a valve, pump trip or start, breaking of pipes etc. TUEV NORD SysTec GmbH and Co. KG performs calculations of pressure surges in power plants and especially in nuclear power plants for many years. For this reason TUEV NORD has developed and qualified the pressure surge computer code DYVRO. This contribution describes in detail the actual code version DYVRO mod. 3 that has been modified with regard to the system of partial differential equations and the numerical scheme. Also the validation against representative experiments like the Simpson's experiment and an experiment at the Cold Water Hammer Test Facility CWHTF is shown. Results of DYVRO calculations are afterwards compared with results of own and external simulations with system codes (ATHLET and RELAP5) and with the pressure surge code WAHA. For this purpose the outcome of the EU project WAHALOADS that was supported within the 5{sup th} framework programme has been used. (orig.)

  4. Fluid-Structure Interaction Analysis for Pressurizer Surge Line subjected to Thermal Stratification

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dong Gu; Jhung, Myung Jo; Yang, Chae Yong [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2012-05-15

    Fluid-Structure Interactions (FSIs) occurring inevitably in operating reactor component systems can cause excessive force or stress to the structures resulting in mechanical damages that may eventually threaten the structural integrity of components. To solve FSI problems, results from one field (fluid-thermal) analysis are applied as loads in other fields (structural) analysis. If two media with different densities flow inside a pipe, thermal stratification can occur. Warm water is lighter than cool water and therefore tends to float on top of the cooler and heavier water, resulting in the upper portion of the pipe being hotter than the lower portion. Under these conditions, differential thermal expansion of the pipe metal can cause the pipe to deflect significantly. Unexpected piping movements are highly undesirable because of potential high piping stress that may exceed design limits for fatigue and stress. In PWRs, there are great possibilities of occurrence of thermal stratification at the feed water lines of the steam generator, at the pressurizer surge line and at the injection pipes of the emergency core cooling systems. The most affected pipe by the thermal stratification is reported to be the pressurizer surge line. Therefore in this study, a thermal-stress simulation is performed using ANSYS FSI. For the pressurizer surge line, thermal loads are transferred from ANSYS CFX to ANSYS Multiphysics in order to determine the heat transfer between the fluid and the solid body. From this information, stresses are determined and ultimately a fatigue analysis is performed

  5. A hybrid inventory management system respondingto regular demand and surge demand

    Energy Technology Data Exchange (ETDEWEB)

    Mohammad S. Roni; Mingzhou Jin; Sandra D. Eksioglu

    2014-06-01

    This paper proposes a hybrid policy for a stochastic inventory system facing regular demand and surge demand. The combination of two different demand patterns can be observed in many areas, such as healthcare inventory and humanitarian supply chain management. The surge demand has a lower arrival rate but higher demand volume per arrival. The solution approach proposed in this paper incorporates the level crossing method and mixed integer programming technique to optimize the hybrid inventory policy with both regular orders and emergency orders. The level crossing method is applied to obtain the equilibrium distributions of inventory levels under a given policy. The model is further transformed into a mixed integer program to identify an optimal hybrid policy. A sensitivity analysis is conducted to investigate the impact of parameters on the optimal inventory policy and minimum cost. Numerical results clearly show the benefit of using the proposed hybrid inventory model. The model and solution approach could help healthcare providers or humanitarian logistics providers in managing their emergency supplies in responding to surge demands.

  6. Security, Violent Events, and Anticipated Surge Capabilities of Emergency Departments in Washington State.

    Science.gov (United States)

    Weyand, Jonathan S; Junck, Emily; Kang, Christopher S; Heiner, Jason D

    2017-04-01

    Over the past 15 years, violent threats and acts against hospital patients, staff, and providers have increased and escalated. The leading area for violence is the emergency department (ED) given its 24/7 operations, role in patient care, admissions gateway, and center for influxes during acute surge events. This investigation had three objectives: to assess the current security of Washington State EDs; to estimate the prevalence of and response to threats and violence in Washington State EDs; and to appraise the Washington State ED security capability to respond to acute influxes of patients, bystanders, and media during acute surge events. A voluntary, blinded, 28-question Web-based survey developed by emergency physicians was electronically delivered to all 87 Washington State ED directors in January 2013. We evaluated responses by descriptive statistical analyses. Analyses occurred after 90% (78/87) of ED directors responded. Annual censuses of the EDs ranged from surge event, 35% believed the initial additional security response would not be adequate, with 26% reporting no additional security would be available within 15 minutes. Our study reveals the variability of ED security staffing and a heterogeneity of capabilities throughout Washington State. These deficiencies and vulnerabilities highlight the need for other EDs and regional emergency preparedness planners to conduct their own readiness assessments.

  7. Full scale lightning surge tests of distribution transformers and secondary systems

    Energy Technology Data Exchange (ETDEWEB)

    Goedde, G.L.; Dugan, R.C. Sr.; Rowe, L.D. (Cooper Power Systems, Thomas A. Edison Technical Center, Franksville, WI (US))

    1992-07-01

    This paper reports that low-side surges are known to cause failures of distribution transformers. They also subject load devices to overvoltages. A full-scale model of a residential service has been set up in a laboratory and subjected to impulses approximating lightning strokes. The tests were made to determine the impulse characteristics of the secondary system and to test the validity of previous analyses. Among the variables investigated were stroke location, the balance of the surges in the service cable, and the effectiveness of arrester protection. Low-side surges were found to consist of two basic components: the natural frequency of the system and the inductive response of the system to the stoke current. The latter component is responsible for transformer failures while the former may be responsible for discharge spots often found around secondary bushings. Arresters at the service entrance are effective in diverting most of the energy from a lightning strike, but may not protect sensitive loads. Additional local protection is also needed. The tests affirmed previous simulations and uncovered additional phenomena as well.

  8. A methodology for extreme groundwater surge predetermination in carbonate aquifers: Groundwater flood frequency analysis

    Science.gov (United States)

    Najib, K.; Jourde, H.; Pistre, S.

    2008-04-01

    SummaryThe present paper introduces a methodology devoted to groundwater flooding hazard assessment. It focuses on groundwater floodings due to water table rises that are induced by heavy rainfall events. This special kind of flooding can cause devastating damages, particularly in fractured and karstified carbonate aquifers. Indeed, hydrodynamic conditions prevailing in these heterogeneous formations can involve strong groundwater surges. The developed methodology shows how flood frequency analysis methods can be applied in groundwater flood frequency analysis. Actually, it consists in estimating the T-year hydraulic head that characterizes the T-year groundwater surge, given a return period T. It also aims at defining the rainfall events likely to cause such extreme groundwater surges. This methodology was applied within the framework of a building construction project in a karstic Mediterranean aquifer located in Southern France. The present paper is designated to be a first contribution to groundwater flood frequency analysis. This new field of research has to be further developed in order to put forward consensus guidelines for hydrogeologists and decision-makers as in flood frequency analysis.

  9. Probabilistic Dressing of a Storm Surge Prediction in the Adriatic Sea

    Directory of Open Access Journals (Sweden)

    R. Mel

    2016-01-01

    Full Text Available Providing a reliable, accurate, and fully informative storm surge forecast is of paramount importance for managing the hazards threatening coastal environments. Specifically, a reliable probabilistic forecast is crucial for the management of the movable barriers that are planned to become operational in 2018 for the protection of Venice and its lagoon. However, a probabilistic forecast requires multiple simulations and a considerable computational time, which makes it expensive in real-time applications. This paper describes the ensemble dressing method, a cheap operational flood prediction system that includes information about the uncertainty of the ensemble members by computing it directly from the meteorological input and the local spread distribution, without requiring multiple forecasts. Here, a sophisticated error distribution form is developed, which includes the superposition of the uncertainty caused by inaccuracies of the ensemble prediction system, which depends on surge level and lead time, and the uncertainty of the meteorological forcing, which is described using a combination of cross-basin pressure gradients. The ensemble dressing is validated over a 3-month-long period in the year 2010, during which an exceptional sequence of storm surges occurred. Results demonstrate that this computationally cheap method can provide an acceptably realistic estimate of the uncertainty.

  10. Interactions between seagrasses and seaweeds during surge nitrogen acquisition determine interspecific competition.

    Science.gov (United States)

    Alexandre, Ana; Baeta, Alexandra; Engelen, Aschwin H; Santos, Rui

    2017-10-20

    Seagrasses dominate shallow coastal environments where nitrogen (N) availability in the water column is often sporadic and mainly in the form of pulses. We investigated the N uptake competition between seagrasses and seaweeds through a series of 15N surge uptake experiments combining single-species and mixed incubations across ammonium concentrations. N surge uptake rates of seagrasses were 2 to 14-fold higher than those of seaweeds in the majority of combinations, showing that seagrasses are generally in a competitive advantage over seaweeds in N-poor environments with N-pulses. No threshold concentration of ammonium was found beyond which seaweeds performed better than seagrasses. Mixed incubations revealed interspecific interactions that affected rates positively and negatively. Uptake rates obtained in single-species incubations, therefore, cannot always be used to predict the outcome of uptake competition. Only two (Zostera marina vs. Ulva rotundata and Zostera marina vs. Codium decorticatum) of the nine combinations tested (Z. marina, Z. noltei and Cymodocea nodosa vs. U. rotundata, C. decorticatum and Dictyota dichotoma) were found to enhance macroalgal uptake. Our results showed that the surge uptake capacity of seagrasses represents an important mechanism in their N acquisition strategy that justifies their dominance in shallow oligotrophic environments.

  11. Effects of storm surge erosion on waterfowl habitats at the Kashunuk River, Yukon-Kuskokwim Delta, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Erosion, accelerated by storm surges, resulted in a 0.11 loss of vegetation and an alteration of species composition within coastal fringe plant communities of the...

  12. Development of wave and surge atlas for the design and protection of coastal bridges in South Louisiana.

    Science.gov (United States)

    2015-02-01

    This report summarizes the work performed by Ocean Engineering Associates, Inc. (OEA), a division : of INTERA Inc. (OEA/INTERA), for Louisiana Department of Transportation and Development : (DOTD) on (1) the development of a Wave and Surge Atlas for ...

  13. Towards Autonomous Control of Hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Conrad, Finn

    1998-01-01

    Presentation of new developed control algorithms to increase autonomy and intelligence of hydraulic control systems. A refinement of relaytuning method is used to determine the control parameters of a lag/lead controller and a poleplacement controller. Further, a fail-safe function is developed...... to hinder surges and mechanical fractures. Experimental results verify the performance of the controllers....

  14. Modeling of Coastal Inundation, Storm Surge, and Relative Sea-Level Rise at Naval Station Norfolk, Norfolk, Virginia, USA

    Science.gov (United States)

    2013-01-01

    balance equation is described by Mase (2001). Additional model features include the grid nesting capability, variable rectangle cells, wave transmission...1980). The storm return periods were determined primarily by examining water-surface elevations measured at local tidal gauges and storm surges...increase due to wind is trivial under the 2-m RSLR scenario. The different area change is determined by peak surge-level values, which are 3.643 and

  15. Purple pitcher plant (Sarracenia rosea Dieback and partial community disassembly following experimental storm surge in a coastal pitcher plant bog.

    Directory of Open Access Journals (Sweden)

    Matthew J Abbott

    Full Text Available Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment. There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change.

  16. Glacier surges and landforms in a permafrost environment at the tidewater glacier Paulabreen, inner Van Mijenfjorden, Svalbard

    OpenAIRE

    Kristensen, Lene

    2009-01-01

    This thesis presents a study of the landsystem of the Svalbard tidewater glacier Paulabreen and its late Holocene surge moraines, focusing on the glaciology and the glacial geology. An active surge of Skobreen/Paulabreen was observed and the glacier dynamics and stress regime was studied using satellite images, a time-lapse movie and photographs. A persistent subglacial conduit was found beneath the medial moraine between Paulabreen and Bakaninbreen, and we postulate that this constrained sur...

  17. Intracerebroventricular Infusion of Vasoactive Intestinal Peptide (VIP Rescues the Luteinizing Hormone Surge in Middle-Aged Female Rats

    Directory of Open Access Journals (Sweden)

    Yan eSun

    2012-02-01

    Full Text Available Reproductive aging is characterized by delayed and attenuated luteinizing hormone (LH surges apparent in middle-aged rats. The suprachiasmatic nucleus (SCN contains the circadian clock that is responsible for the timing of diverse neuroendocrine rhythms. Electrophysiological studies suggest vasoactive intestinal peptide (VIP originating from the SCN excites gonadotropin-releasing hormone (GnRH neurons and affects daily patterns of GnRH-LH release. Age-related LH surge dysfunction correlates with reduced VIP mRNA expression in the SCN and fewer GnRH neurons with VIP contacts expressing c-fos, a marker of neuronal activation, on the day of the LH surge. To determine if age-related LH surge dysfunction reflects reduced VIP availability or altered VIP responsiveness under estradiol positive feedback conditions, we assessed the effect of intracerebroventricular (icv VIP infusion on c-fos expression in GnRH neurons and on LH release in ovariohysterectomized, hormone-primed young and middle-aged rats. Icv infusion of VIP between 1300 and 1600 h significantly advanced the time of peak LH release, increased total and peak LH release, and increased the number of GnRH neurons expressing c-fos on the day of the LH surge in middle-aged rats. Surprisingly, icv infusion of VIP in young females significantly reduced the number of GnRH neurons expressing c-fos and delayed and reduced the LH surge. These observations suggest that a critical balance of VIP signaling is required to activate GnRH neurons for an appropriately timed and robust LH surge in young and middle-aged females. Age-related LH surge changes may, in part, result from decreased availability and reduced VIP-mediated neurotransmission under estradiol positive feedback conditions.

  18. Investigating a pediatric hospital's response to an inpatient census surge during the 2009 H1N1 influenza pandemic.

    Science.gov (United States)

    Van Cleve, William C; Hagan, Pat; Lozano, Paula; Mangione-Smith, Rita

    2011-08-01

    On November 4, 2009, the 250-bed Seattle Children's Hospital (SCH) identified a surge in its census--245 inpatients, well above the average midnight census of 207. In response, SCH activated its pandemic influenza surge plan in an effort to decrease the inpatient census. Within 16 hours, 51 patients (20.4% of total bed capacity) had been discharged, and inpatient census at SCH decreased to 222 patients. As part of a quality improvement project, SCH's response to the surge was investigated, with data drawn from interviews, a review of records created in the course of the surge plan implementation, an e-mail survey of attending physicians responsible for patient discharges, and models examining predictors of hospital discharges. Analysis of three years of hospital data (2007-2009) indicated that the high census on November 4 was an uncommon but not unprecedented occurrence. In addition, there was a clear positive association between an evening's census and the number of discharges during the following 24 hours. SCH discharged essentially the same number of patients on November 4 as on previous high-census days when the surge plan was not activated, suggesting that the surge plan did not succeed in creating excess discharges. Increasingly, evidence indicates that care quality depends on the degree to which hospital resources are sufficient to meet demand. Reverse triage, at least as implemented by SCH on November 4, 2009, is unlikely to represent an effective solution to surge outside of a disaster setting because of its requirement for centralized decision making. SCH has incorporated the results of this review into the way that it collects and analyzes data, manages flow, and responds to inpatient surges.

  19. Purple pitcher plant (Sarracenia rosea) Dieback and partial community disassembly following experimental storm surge in a coastal pitcher plant bog.

    Science.gov (United States)

    Abbott, Matthew J; Battaglia, Loretta L

    2015-01-01

    Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea) are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea) were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment). There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change.

  20. Exposure to Acute Psychosocial Stress Disrupts the Luteinizing Hormone Surge Independent of Estrous Cycle Alterations in Female Mice.

    Science.gov (United States)

    Wagenmaker, Elizabeth R; Moenter, Suzanne M

    2017-08-01

    The disruptive effects of severe stress on reproductive function are well documented, but surprisingly few studies exist that demonstrate milder psychosocial stressors interfere with the ovarian cycle in females. We hypothesized repeated application of psychosocial stress would disrupt estrous cycles in mice. Mice were transferred to a new cage, transported to a new room, and restrained (2 hours) for 21 consecutive days. Contrary to our hypothesis, this paradigm did not affect estrous cycles. We next tested the hypothesis that a single exposure to mild stress disrupts a specific aspect of the cycle: the proestrous luteinizing hormone (LH) surge. We developed a model of acute, layered psychosocial stress (sequential application of new cage, transport to new room, restraint and predator cues lasting 5 hours total) that consistently increased circulating corticosterone. Application of this stress paradigm on midmorning of proestrus disrupted the LH surge measured near lights out in 14 of 24 mice; there was no evidence for a 24-hour delay of the surge. Following stress, mice continued to have normal estrous cycles, even when the LH surge was disrupted. Stressed mice failing to exhibit an LH surge had uterine masses suggesting the proestrous estradiol rise occurred. To test specifically whether the layered stress paradigm blocks estradiol-dependent positive feedback mechanisms, we examined the estradiol-induced LH surge. Stress blocked the estradiol-induced LH surge in all mice. These results suggest exposure to mild, acute psychosocial stress on proestrus can severely disrupt the generation of the LH surge in mice without affecting the overall estrous cycle. Copyright © 2017 Endocrine Society.

  1. The naturally occurring luteinizing hormone surge is diminished in mice lacking estrogen receptor Beta in the ovary.

    Science.gov (United States)

    Jayes, Friederike L; Burns, Katherine A; Rodriguez, Karina F; Kissling, Grace E; Korach, Kenneth S

    2014-02-01

    Female ESR2-null mice (betaERKO) display defects in ovarian function and are subfertile. Follicular maturation is impaired and explains smaller litters, but betaERKO also produce fewer litters, which may be partially due to inadequate ovulatory signals. To test this, the amplitude and timing of the naturally occurring luteinizing hormone (LH) surge was measured in individual intact betaERKO and wild-type (WT) mice. Vaginal cytology was evaluated daily, and blood samples were taken from mice in proestrus. The amplitude of the LH surge was severely blunted in betaERKO mice compared to WT, but pituitary LH levels revealed no differences. The betaERKO mice did not produce a preovulatory estradiol surge. To determine if the smaller LH surges and the reduced number of litters in betaERKO were due to the lack of ESR2 in the hypothalamic-pituitary axis or due to the absence of ESR2 in the ovary, ovaries were transplanted from WT into betaERKO mice and vice versa. The size of the LH surge was reduced only in mice lacking ESR2 within the ovary, and these mice had fewer litters. Fertility and size of the LH surge were rescued in betaERKO mice receiving a WT ovary. These data provide the first experimental evidence that the LH surge is impaired in betaERKO females and may contribute to their reduced fertility. ESR2 is not necessary within the pituitary and hypothalamus for the generation of a normal LH surge and for normal fertility, but ESR2 is essential within the ovary to provide proper signals.

  2. The Naturally Occurring Luteinizing Hormone Surge Is Diminished in Mice Lacking Estrogen Receptor Beta in the Ovary1

    Science.gov (United States)

    Jayes, Friederike L.; Burns, Katherine A.; Rodriguez, Karina F.; Kissling, Grace E.; Korach, Kenneth S.

    2013-01-01

    ABSTRACT Female ESR2-null mice (betaERKO) display defects in ovarian function and are subfertile. Follicular maturation is impaired and explains smaller litters, but betaERKO also produce fewer litters, which may be partially due to inadequate ovulatory signals. To test this, the amplitude and timing of the naturally occurring luteinizing hormone (LH) surge was measured in individual intact betaERKO and wild-type (WT) mice. Vaginal cytology was evaluated daily, and blood samples were taken from mice in proestrus. The amplitude of the LH surge was severely blunted in betaERKO mice compared to WT, but pituitary LH levels revealed no differences. The betaERKO mice did not produce a preovulatory estradiol surge. To determine if the smaller LH surges and the reduced number of litters in betaERKO were due to the lack of ESR2 in the hypothalamic-pituitary axis or due to the absence of ESR2 in the ovary, ovaries were transplanted from WT into betaERKO mice and vice versa. The size of the LH surge was reduced only in mice lacking ESR2 within the ovary, and these mice had fewer litters. Fertility and size of the LH surge were rescued in betaERKO mice receiving a WT ovary. These data provide the first experimental evidence that the LH surge is impaired in betaERKO females and may contribute to their reduced fertility. ESR2 is not necessary within the pituitary and hypothalamus for the generation of a normal LH surge and for normal fertility, but ESR2 is essential within the ovary to provide proper signals. PMID:24337314

  3. Intracerebroventricular infusion of vasoactive intestinal Peptide rescues the luteinizing hormone surge in middle-aged female rats.

    Science.gov (United States)

    Sun, Yan; Shu, Jun; Kyei, Kwame; Neal-Perry, Genevieve S

    2012-01-01

    Reproductive aging is characterized by delayed and attenuated luteinizing hormone (LH) surges apparent in middle-aged rats. The suprachiasmatic nucleus (SCN) contains the circadian clock that is responsible for the timing of diverse neuroendocrine rhythms. Electrophysiological studies suggest vasoactive intestinal peptide (VIP) originating from the SCN excites gonadotropin-releasing hormone (GnRH) neurons and affects daily patterns of GnRH-LH release. Age-related LH surge dysfunction correlates with reduced VIP mRNA expression in the SCN and fewer GnRH neurons with VIP contacts expressing c-fos, a marker of neuronal activation, on the day of the LH surge. To determine if age-related LH surge dysfunction reflects reduced VIP availability or altered VIP responsiveness under estradiol positive feedback conditions, we assessed the effect of intracerebroventricular (icv) VIP infusion on c-fos expression in GnRH neurons and on LH release in ovariohysterectomized, hormone-primed young and middle-aged rats. Icv infusion of VIP between 1300 and 1600 h significantly advanced the time of peak LH release, increased total and peak LH release, and increased the number of GnRH neurons expressing c-fos on the day of the LH surge in middle-aged rats. Surprisingly, icv infusion of VIP in young females significantly reduced the number of GnRH neurons expressing c-fos and delayed and reduced the LH surge. These observations suggest that a critical balance of VIP signaling is required to activate GnRH neurons for an appropriately timed and robust LH surge in young and middle-aged females. Age-related LH surge changes may, in part, result from decreased availability and reduced VIP-mediated neurotransmission under estradiol positive feedback conditions.

  4. Nimodipine, a calcium channel blocker, delays the spontaneous LH surge in women with regular menstrual cycles: a prospective pilot study

    Science.gov (United States)

    2013-01-01

    Background Currently GnRH analogue injections are used to prevent premature LH surges in women undergoing assisted reproductive technology. This was a pilot study to determine the safety and effectiveness of nimodipine, an oral calcium channel blocker, to delay the mid-cycle spontaneous LH surge in women with regular menstrual cycles. Methods Eight women with regular menstrual cycles self-monitored three consecutive cycles for the day of an LH surge by daily urine assay. The first and third cycles were observatory. In the second cycle, subjects took nimodipine 60 mg by mouth three times daily for four days, starting two days prior to the expected LH surge day based on cycle one. Results The LH surge day in cycle 2 (nimodipine) was significantly delayed in comparison to both observatory cycle 1 (15.5+/−3.4 vs 14.0+/−2.8 days; p = 0.033) and cycle 3 (15.1+/−3.5 vs 13.1+/−2.4 days; p = 0.044). There was no difference in the LH surge day between the two observatory cycles (13.4+/−2.4 vs 13.1+/−2.4 days; p = 0.457). Three patients experienced a mild headache. Conclusions There was a statistically significant delay in the spontaneous LH surge day in the treatment cycle in comparison to both observatory cycles. Nimopidine should be further investigated as an oral alternative to delay a spontaneous LH surge. PMID:23391256

  5. Intracerebroventricular Infusion of Vasoactive Intestinal Peptide Rescues the Luteinizing Hormone Surge in Middle-Aged Female Rats

    Science.gov (United States)

    Sun, Yan; Shu, Jun; Kyei, Kwame; Neal-Perry, Genevieve S.

    2012-01-01

    Reproductive aging is characterized by delayed and attenuated luteinizing hormone (LH) surges apparent in middle-aged rats. The suprachiasmatic nucleus (SCN) contains the circadian clock that is responsible for the timing of diverse neuroendocrine rhythms. Electrophysiological studies suggest vasoactive intestinal peptide (VIP) originating from the SCN excites gonadotropin-releasing hormone (GnRH) neurons and affects daily patterns of GnRH–LH release. Age-related LH surge dysfunction correlates with reduced VIP mRNA expression in the SCN and fewer GnRH neurons with VIP contacts expressing c-fos, a marker of neuronal activation, on the day of the LH surge. To determine if age-related LH surge dysfunction reflects reduced VIP availability or altered VIP responsiveness under estradiol positive feedback conditions, we assessed the effect of intracerebroventricular (icv) VIP infusion on c-fos expression in GnRH neurons and on LH release in ovariohysterectomized, hormone-primed young and middle-aged rats. Icv infusion of VIP between 1300 and 1600 h significantly advanced the time of peak LH release, increased total and peak LH release, and increased the number of GnRH neurons expressing c-fos on the day of the LH surge in middle-aged rats. Surprisingly, icv infusion of VIP in young females significantly reduced the number of GnRH neurons expressing c-fos and delayed and reduced the LH surge. These observations suggest that a critical balance of VIP signaling is required to activate GnRH neurons for an appropriately timed and robust LH surge in young and middle-aged females. Age-related LH surge changes may, in part, result from decreased availability and reduced VIP-mediated neurotransmission under estradiol positive feedback conditions. PMID:22654857

  6. Nimodipine, a calcium channel blocker, delays the spontaneous LH surge in women with regular menstrual cycles: a prospective pilot study

    Directory of Open Access Journals (Sweden)

    Nayot Dan

    2013-02-01

    Full Text Available Abstract Background Currently GnRH analogue injections are used to prevent premature LH surges in women undergoing assisted reproductive technology. This was a pilot study to determine the safety and effectiveness of nimodipine, an oral calcium channel blocker, to delay the mid-cycle spontaneous LH surge in women with regular menstrual cycles. Methods Eight women with regular menstrual cycles self-monitored three consecutive cycles for the day of an LH surge by daily urine assay. The first and third cycles were observatory. In the second cycle, subjects took nimodipine 60 mg by mouth three times daily for four days, starting two days prior to the expected LH surge day based on cycle one. Results The LH surge day in cycle 2 (nimodipine was significantly delayed in comparison to both observatory cycle 1 (15.5+/−3.4 vs 14.0+/−2.8 days; p = 0.033 and cycle 3 (15.1+/−3.5 vs 13.1+/−2.4 days; p = 0.044. There was no difference in the LH surge day between the two observatory cycles (13.4+/−2.4 vs 13.1+/−2.4 days; p = 0.457. Three patients experienced a mild headache. Conclusions There was a statistically significant delay in the spontaneous LH surge day in the treatment cycle in comparison to both observatory cycles. Nimopidine should be further investigated as an oral alternative to delay a spontaneous LH surge.

  7. Formation of Cyclic Steps due to the Surge-type Turbidity Currents in a Flume Experiment

    Science.gov (United States)

    Yokokawa, M.

    2016-12-01

    Supercritical turbidity currents often form crescentic step-like wavy structures, which have been found at the submarine canyons, and deltaic environments. Field observations of turbidity currents and seabed topography on the Squamish delta in British Columbia, Canada revealed that cyclic steps formed by the surge-type turbidity currents (e.g., Hughes Clarke et al., 2012a; 2012b; 2014). The high-density portion of the flow, which affects the sea floor morphology, lasted only 30-60 seconds. The questions arise if we can reconstruct paleo-flow condition from the morphologic features of these steps. We don't know answers right now because there have been no experiments about the formative conditions of cyclic steps due to the "surge-type" turbidity currents. Here we did preliminary experiments on the formation of cyclic steps due to the multiple surge-type density currents, and compare the morphology of the steps with those of Squamish delta. First of all, we measured wave length and wave height of each step from profiles of each channels of Squamish delta from the elevation data and calculated the wave steepness. Wave steepness of active steps ranges about 0.05 to 0.15, which is relatively larger compare with those of other sediment waves. And in general, wave steepness is larger in the proximal region. The experiments had been performed at Osaka Institute of Technology. A flume, which is 7.0 m long, 0.3 m deep and 2 cm wide, was suspended in a larger tank, which is 7.6 m long, 1.2 m deep and 0.3 m wide, filled with water. The inner flume tilted at 7 degrees. Mixture of salt water (1.17 g/cm3) and plastic particles (1.5 g/cm3, 0.1-0.18 mm in diameter), whose weight ratio is 10:1, poured into the upstream end of the inner flume from head tank for 5 seconds. Discharge of the mixture was 240mL/s, thus for 5seconds 1200mL of mixture was released into the inner flume. We made 130 surges. As a result, four steps were formed ultimately, which were moving toward upstream

  8. Typhoon Haiyan-Induced Storm Surge Simulation in Metro Manila Using High-Resolution LiDAR Topographic Data

    Science.gov (United States)

    Santiago, J. T.

    2015-12-01

    Storm surge is the abnormal rise in sea water over and above astronomical tides due to a forthcoming storm. Developing an early warning system for storm surges is vital due to the high level of hazard they might cause. On 08 November 2013, Typhoon Haiyan generated storm surges that killed over 6,000 people in the central part of the Philippines. The Nationwide Operational Assessment of Hazards under the Department of Science and Technology was tasked to create storm surge hazard maps for the country's coastal areas. The research project aims to generate storm surge hazard maps that can be used for disaster mitigation and planning. As part of the research, the team explored a scenario wherein a tropical cyclone hits the Metro Manila with strength as strong as Typhoon Haiyan. The area was chosen primarily for its political, economic and cultural significance as the country's capital. Using Japan Meteorological Agency Storm Surge model, FLO2D flooding software, LiDAR topographic data, and GIS technology, the effects of a Haiyan-induced tropical cyclone passing through Metro Manila was examined. The population affected, number of affected critical facilities, and potential evacuation sites were identified. The outputs of this study can be used by the authorities as basis for policies that involve disaster risk reduction and management.

  9. Quiescent-phase evolution of a surge-type glacier: Black Rapids Glacier, Alaska, U.S.A.

    Science.gov (United States)

    Heinrichs, T.A.; Mayo, L.R.; Echelmeyer, K.A.; Harrison, W.D.

    1996-01-01

    Black Rapids Glacier, a surge-type glacier in the Alaska Range, most recently surged in 1936-37 and is currently in its quiescent phase. Mass balance, ice velocity and thickness change have been measured at three to ten sites from 1972 to 1994. The annual speed has undergone cyclical fluctuations of as much as 45% about the mean speed. Ice thickness and surface slope did not change enough to cause the speed fluctuations through changes in ice deformation, which indicates that they are being driven by changes in basal motion. The behavior of Black Rapids Glacier during this quiescent phase is significantly different from that of Variegated Glacier, another well-studied surge-type glacier in Alaska. The present medial-moraine configuration of Black Rapids Glacier indicates that a surge could occur at any time. However, ice velocity data indicate that the next surge may not be imminent. We believe that there is little chance that the next surge will cross and dam the Delta River.

  10. Hypothalamic effects of progesterone on regulation of the pulsatile and surge release of luteinising hormone in female rats.

    Science.gov (United States)

    He, Wen; Li, Xiaofeng; Adekunbi, Daniel; Liu, Yali; Long, Hui; Wang, Li; Lyu, Qifeng; Kuang, Yanping; O'Byrne, Kevin T

    2017-08-14

    Progesterone can block the oestradiol-induced GnRH/LH surge and inhibit LH pulse frequency. Recent studies reported that progesterone prevented premature LH surges during ovarian hyperstimulation in women. As the most potent stimulator of GnRH/LH release, kisspeptin is believed to mediate the positive and negative feedback effects of oestradiol in the hypothalamic anteroventral periventricular (AVPV) and arcuate (ARC) nuclei, while the region-specific role of progesterone receptors in these nuclei remains unknown. This study examined the hypothesis that progesterone inhibits LH surge and pulsatile secretion via its receptor in the ARC and/or AVPV nuclei. Adult female rats received a single injection of pregnant mare serum gonadotropin followed by progesterone or vehicle. Progesterone administration resulted in a significant prolongation of the oestrous cycle and blockade of LH surge. However, microinjection of the progesterone receptor antagonist, RU486, into the AVPV reversed the prolonged cycle length and rescued the progesterone blockade LH surge, while RU486 into the ARC shortened LH pulse interval in the progesterone treated rats. These results demonstrated that progesterone's inhibitory effect on the GnRH/LH surge and pulsatile secretion is mediated by its receptor in the kisspeptin enriched hypothalamic AVPV and ARC respectively, which are essential for progesterone regulation of oestrous cyclicity in rats.

  11. Influence of potential sea level rise on societal vulnerability to hurricane storm-surge hazards, Sarasota County, Florida

    Science.gov (United States)

    Frazier, Tim G.; Wood, Nathan; Yarnal, Brent; Bauer, Denise H.

    2010-01-01

    Although the potential for hurricanes under current climatic conditions continue to threaten coastal communities, there is concern that climate change, specifically potential increases in sea level, could influence the impacts of future hurricanes. To examine the potential effect of sea level rise on community vulnerability to future hurricanes, we assess variations in socioeconomic exposure in Sarasota County, FL, to contemporary hurricane storm-surge hazards and to storm-surge hazards enhanced by sea level rise scenarios. Analysis indicates that significant portions of the population, economic activity, and critical facilities are in contemporary and future hurricane storm-surge hazard zones. The addition of sea level rise to contemporary storm-surge hazard zones effectively causes population and asset (infrastructure, natural resources, etc) exposure to be equal to or greater than what is in the hazard zone of the next higher contemporary Saffir–Simpson hurricane category. There is variability among communities for this increased exposure, with greater increases in socioeconomic exposure due to the addition of sea level rise to storm-surge hazard zones as one progresses south along the shoreline. Analysis of the 2050 comprehensive land use plan suggests efforts to manage future growth in residential, economic and infrastructure development in Sarasota County may increase societal exposure to hurricane storm-surge hazards.

  12. Assessing storm surge hazard and impact of sea level rise in the Lesser Antilles case study of Martinique

    Directory of Open Access Journals (Sweden)

    Y. Krien

    2017-09-01

    Full Text Available In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave–current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge – up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

  13. An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate

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    A. Sterl

    2009-09-01

    Full Text Available The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

  14. Impact of Cyclone Track Features and Tidal Phase Shift upon Surge Characteristics in the Bay of Bengal along the Bangladesh Coast

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    Mohammad Asad Hussain

    2017-11-01

    Full Text Available The impact of cyclone track features (e.g., cyclone translation speed, cyclone path and cyclone landfall crossing angle in combination with tidal phase shift upon surge characteristics have been investigated at the Bay of Bengal along the Bangladesh coast. A two-dimensional hydrodynamic model in a horizontal direction (2DH coupled with a storm-surge model has been employed for the study. Numerical experiments with three different cyclone translation speeds show that when the surge height is directly forced by the cyclonic wind speed especially within the RWM (Radius of Maximum Wind, faster translation speed produces reduced surge height as the cyclone gets less time to force the water. On the other hand, at locations outside the RMW, surge waves travel as a propagating long wave where higher surges are produced by faster moving cyclones. It is found that surge arrival times are more and more affected by tidal phase when cyclone translation speed is reduced. Analysis of seven hypothetical parallel cyclone paths show that local bathymetry and complex coastline configurations strongly influence the surge height and surge arrival time along the Bangladesh coast. From the analyses of cyclone landfall crossing angles at the Khulna and Chittagong coasts, it is observed that surge durations are the smallest at both the coasts when the coastline crossing angles are the smallest.

  15. Long-term clinical impact of PSA surge in castration-resistant prostate cancer patients treated with abiraterone.

    Science.gov (United States)

    Conteduca, Vincenza; Caffo, Orazio; Lolli, Cristian; Aieta, Michele; Scarpi, Emanuela; Bianchi, Emanuela; Maines, Francesca; Schepisi, Giuseppe; Salvi, Samanta; Massari, Francesco; Carrozza, Francesco; Veccia, Antonello; Chiuri, Vincenzo E; Campadelli, Enrico; Facchini, Gaetano; De Giorgi, Ugo

    2017-06-01

    Early changes in PSA have been evaluated in association to treatment outcome. The aim of this study was to assess PSA surge phenomenon in castration-resistant prostate cancer (CRPC) patients treated with abiraterone and to correlate those variations with long-term treatment outcome. We retrospectively evaluated 330 CRPC patients in 11 Italian hospitals, monitoring PSA levels at baseline and every 4 weeks. Other clinical, biochemical and molecular parameters were determined at baseline. We considered PSA surge as PSA increase within the first 8 weeks from starting abiraterone more than 1% from baseline followed by a PSA decline. The log-rank test was applied to compare survival between groups of patients according to PSA surge. The impact of PSA surge on survival was evaluated by Cox regression analyses. A total of 330 patients with CRPC, median age 74 years (range, 45-90), received abiraterone (281 chemotherapy-treated and 49 chemotherapy-naïve). PSA surge was observed in 20 (7%) post-chemotherapy and 2 (4%) chemotherapy-naïve patients. For overall patients presenting PSA surge, timing of PSA peak from baseline was 5 ± 1.8 weeks and PSA rise from baseline was 21 ± 18.4%. The overall median follow-up was 23 months (range 1-62). No significant differences in progression-free survival and overall survival were observed between patients with and without PSA surge (P = 0.16 and =0.86, respectively). In addition, uni- and multivariate analyses showed no baseline factors related to PSA surge. PSA surge occurs in both chemotherapy-treated and chemotherapy-naïve patients treated with abiraterone resulting, however, in no long-term impact on outcome. Physicians and patients should be aware of PSA surge challenge to prevent a premature discontinuation of potentially effective therapy with abiraterone. Further larger and prospective studies are warranted to investigate this not infrequent phenomenon. © 2017 Wiley Periodicals, Inc.

  16. Follicular cysts occur after a normal estradiol-induced GnRH/LH surge if the corpus hemorrhagicum is removed.

    Science.gov (United States)

    Gümen, Ahmet; Wiltbank, Milo C

    2005-06-01

    The pathophysiology underlying follicular cysts appears to be lack of an estradiol (E2)-induced GnRH/LH surge due to hypothalamic insensitivity to E2. In addition, progesterone (P4) can cause animals with follicular cysts to resume normal cyclicity and normal hypothalamic responsiveness to E2. We postulated that follicular cysts may be a pathological manifestation of a physiological state that cows, and possibly other species, go through during the normal estrous cycle but the rise in P4 following ovulation induces them back to normal hypothalamic responsiveness to E2. Based on this hypothesis, we expected that removal of the ovary containing the corpus hemorrhagicum would prevent the normal rise in P4 following ovulation and induce development of follicular cysts. Cows (n = 24) on day 7 of the estrous cycle were treated with prostaglandin F2alpha (PGF2alpha) and time of ovulation was detected by ovarian ultrasonography every 8 h. Immediately following detection of ovulation, cows were randomly but unequally assigned to have the ovary containing the corpus hemorrhagicum removed (TRT; n = 16) or the ovary opposite to the corpus hemorrhagicum removed (CON; n = 8). Cows were subsequently evaluated by daily ultrasound and blood sampling to determine follicular dynamics. Ovulation was detected at 93.7 +/- 4.5 h after PGF2alpha injection. All CON cows had a normal estrous cycle length (22.0 +/- 0.6 days) after ovariectomy (OVX). Half of the TRT cows became anovular (TRT-ANO; n = 8) after OVX with large anovular follicles developing on the ovary (maximal size, 25.4 +/- 1.4 mm; range, 20-32 mm). However, eight TRT cows ovulated (TRT-OV; n = 8) 7.3 +/- 0.6 days after OVX. Control cows had a normal P4 rise after ovulation. Removal of the newly formed corpus hemorrhagicum prevented the rise in circulating serum P4 in TRT-ANO cows throughout the 25-day experimental period. The TRT-OV cows had a delayed increase in circulating P4 but it was normal in relation to time of

  17. A better prediction model for patient surges from influenza? New Internet-based tool shows promise, say researchers.

    Science.gov (United States)

    2012-03-01

    In a study focused on Baltimore, MD, researchers have found that data culled from Google Flu Trends, a free Internet-based influenza surveillance system, shows strong correlation with hikes in ED visits from patients with flu-like symptoms. While the approach has yet to be validated in other cities or regions, experts recommend that ED administrators and providers familiarize themselves with the new surveillance tool and stay abreast of developments regarding similar surveillance mechanisms. Google Flu Trends (www.google.org/flutrends/) is a free Internet-based tool that monitors Internet-based searches for flu information. Users can customize their search by location (city, state, country). Researchers say the advantage of this approach over traditional surveillance methods is that it provides real-time data about flu-related activity in a city or region. Traditional approaches, which rely on case reports from the Centers for Disease Control and Prevention, are delayed. Researchers hope to eventually leverage this tool, and perhaps other surveillance data, into a powerful early-warning mechanism that EDs can use to better plan for patient surges due to influenza.

  18. Self-renewal and phenotypic conversion are the main physiological responses of macrophages to the endogenous estrogen surge.

    Science.gov (United States)

    Pepe, Giovanna; Braga, Daniele; Renzi, Tiziana A; Villa, Alessandro; Bolego, Chiara; D'Avila, Francesca; Barlassina, Cristina; Maggi, Adriana; Locati, Massimo; Vegeto, Elisabetta

    2017-03-20

    Beyond the physiology of reproduction, estrogen controls the homeostasis of several tissues. Although macrophages play a key role in tissue remodeling, the interplay with estrogen is still ill defined. Using a transcriptomic approach we first obtained a comprehensive list of genes that are differentially expressed in peritoneal macrophages in response to physiological levels of 17β-estradiol (E2) injected in intact female mice. Our data also showed the dynamic nature of the macrophage response to E2 and pointed to specific biological programs induced by the hormone, with cell proliferation, immune response and wound healing being the most prominent functional categories. Indeed, the exogenous administration of E2 and, more importantly, the endogenous hormonal surge proved to support macrophage proliferation in vivo, as shown by cell cycle gene expression, BrdU incorporation and cell number. Furthermore, E2 promoted an anti-inflammatory and pro-resolving macrophage phenotype, which converged on the induction of genes related to macrophage alternative activation and on IL-10 expression in vivo. Hormone action was maintained in an experimental model of peritoneal inflammation based on zymosan injection. These findings highlight a direct effect of estrogen on macrophage expansion and phenotypic adaptation in homeostatic conditions and suggest a role for this interplay in inflammatory pathologies.

  19. a 24/7 High Resolution Storm Surge, Inundation and Circulation Forecasting System for Florida Coast

    Science.gov (United States)

    Paramygin, V.; Davis, J. R.; Sheng, Y.

    2012-12-01

    A 24/7 forecasting system for Florida is needed because of the high risk of tropical storm surge-induced coastal inundation and damage, and the need to support operational management of water resources, utility infrastructures, and fishery resources. With the anticipated climate change impacts, including sea level rise, coastal areas are facing the challenges of increasing inundation risk and increasing population. Accurate 24/7 forecasting of water level, inundation, and circulation will significantly enhance the sustainability of coastal communities and environments. Supported by the Southeast Coastal Ocean Observing Regional Association (SECOORA) through NOAA IOOS, a 24/7 high-resolution forecasting system for storm surge, coastal inundation, and baroclinic circulation is being developed for Florida using CH3D Storm Surge Modeling System (CH3D-SSMS). CH3D-SSMS is based on the CH3D hydrodynamic model coupled to a coastal wave model SWAN and basin scale surge and wave models. CH3D-SSMS has been verified with surge, wave, and circulation data from several recent hurricanes in the U.S.: Isabel (2003); Charley, Dennis and Ivan (2004); Katrina and Wilma (2005); Ike and Fay (2008); and Irene (2011), as well as typhoons in the Pacific: Fanapi (2010) and Nanmadol (2011). The effects of tropical cyclones on flow and salinity distribution in estuarine and coastal waters has been simulated for Apalachicola Bay as well as Guana-Tolomato-Matanzas Estuary using CH3D-SSMS. The system successfully reproduced different physical phenomena including large waves during Ivan that damaged I-10 Bridges, a large alongshore wave and coastal flooding during Wilma, salinity drop during Fay, and flooding in Taiwan as a result of combined surge and rain effect during Fanapi. The system uses 4 domains that cover entire Florida coastline: West, which covers the Florida panhandle and Tampa Bay; Southwest spans from Florida Keys to Charlotte Harbor; Southeast, covering Biscayne Bay and Miami and

  20. The combined risk of extreme tropical cyclone winds and storm surges along the U.S. Gulf of Mexico Coast

    Science.gov (United States)

    Trepanier, J. C.; Yuan, J.; Jagger, T. H.

    2017-03-01

    Tropical cyclones, with their nearshore high wind speeds and deep storm surges, frequently strike the United States Gulf of Mexico coastline influencing millions of people and disrupting offshore economic activities. The combined risk of occurrence of tropical cyclone nearshore wind speeds and storm surges is assessed at 22 coastal cities throughout the United States Gulf of Mexico. The models used are extreme value copulas fitted with margins defined by the generalized Pareto distribution or combinations of Weibull, gamma, lognormal, or normal distributions. The statistical relationships between the nearshore wind speed and storm surge are provided for each coastal city prior to the copula model runs using Spearman's rank correlations. The strongest significant relationship between the nearshore wind speed and storm surge exists at Shell Beach, LA (ρ = 0.67), followed by South Padre Island, TX (ρ = 0.64). The extreme value Archimedean copula models for each city then provide return periods for specific nearshore wind speed and storm surge pairs. Of the 22 cities considered, Bay St. Louis, MS, has the shortest return period for a tropical cyclone with at least a 50 ms-1 nearshore wind speed and a 3 m surge (19.5 years, 17.1-23.5). The 90% confidence intervals are created by recalculating the return periods for a fixed set of wind speeds and surge levels using 100 samples of the model parameters. The results of this study can be utilized by policy managers and government officials concerned with coastal populations and economic activity in the Gulf of Mexico.

  1. Global but not gonadotrope-specific disruption of Bmal1 abolishes the luteinizing hormone surge without affecting ovulation.

    Science.gov (United States)

    Chu, Adrienne; Zhu, Lei; Blum, Ian D; Mai, Oliver; Leliavski, Alexei; Fahrenkrug, Jan; Oster, Henrik; Boehm, Ulrich; Storch, Kai-Florian

    2013-08-01

    Although there is evidence for a circadian regulation of the preovulatory LH surge, the contributions of individual tissue clocks to this process remain unclear. We studied female mice deficient in the Bmal1 gene (Bmal1(-/-)), which is essential for circadian clock function, and found that they lack the proestrous LH surge. However, spontaneous ovulation on the day of estrus was unaffected in these animals. Bmal1(-/-) females were also deficient in the proestrous FSH surge, which, like the LH surge, is GnRH-dependent. In the absence of circadian or external timing cues, Bmal1(-/-) females continued to cycle in constant darkness albeit with increased cycle length and time spent in estrus. Because pituitary gonadotropes are the source of circulating LH and FSH, we assessed hypophyseal circadian clock function and found that female pituitaries rhythmically express clock components throughout all cycle stages. To determine the role of the gonadotrope clock in the preovulatory LH and FSH surge process, we generated mice that specifically lack BMAL1 in gonadotropes (GBmal1KO). GBmal1KO females exhibited a modest elevation in both proestrous and baseline LH levels across all estrous stages. BMAL1 elimination from gonadotropes also led to increased variability in estrous cycle length, yet GBmal1KO animals were otherwise reproductively normal. Together our data suggest that the intrinsic clock in gonadotropes is dispensable for LH surge regulation but contributes to estrous cycle robustness. Thus, clocks in the suprachiasmatic nucleus or elsewhere must be involved in the generation of the LH surge, which, surprisingly, is not required for spontaneous ovulation.

  2. Investigation of the impact of the surge caused by a full load rejection on the freeboard design

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.M.; Sydor, K.; Lemke, D. [Manitoba Hydro, Winnipeg, MB (Canada)

    2008-07-01

    Dam engineers use numerical and physical modeling to better understand the fluid flow phenomena of a water resource project and to explore different design options to maximize operation efficiency. Manitoba Hydro has used computational fluid dynamics (CFD) analysis to advance the hydraulic design of many projects. In this study, the effect of the surcharge caused by a powerhouse load rejection on the dam design was studied, as well as the available reaction times to mobilize the spill following such an incident. Canadian dam safety guidelines stipulate that the wave run-up, wind set-up, landslide and earthquake effects should be considered when determining freeboard design. However, the guidelines do not take into account the possibility of a surge caused by a powerhouse full load rejection even though it is an important requirement in determining available reaction times to mobilize the necessary spill following an incident. This paper presented an application of the surge analysis in the design of the Wuskwatim generating station using CFD. The surge in the powerhouse intake channel following a powerhouse full load rejection was simulated using flow 3D and CFD software. Normal flow and probable maximum flood (PMF) conditions were also considered in the simulation. The inflow and outflow boundary conditions were applied in the model in terms of mass source and sink. A sensitivity analysis was conducted to determine the effects of upstream boundary conditions on the surge characteristics. Although the initial surge for PMF case was found to be slightly higher than that for normal flow, the study showed that the maximum surge induced by power station shut down would probably not exceed the present design crest levels of the powerhouse, main dam and north dyke. It was concluded that designers should ensure that the surge caused by the load rejection in both normal flow and PMF flow cases will not exceed the freeboard in the design. 7 refs., 3 tabs., 8 figs.

  3. Investigating changes in basal conditions of Variegated Glacier prior to and during its 1982–1983 surge

    Directory of Open Access Journals (Sweden)

    M. Jay-Allemand

    2011-08-01

    Full Text Available Variegated Glacier (Alaska is known to surge periodically after a sufficient amount of cumulative mass balance is reached, but this observation is difficult to link with changes in the basal conditions. Here, using a 10-yr dataset, consisting of surface topography and surface velocity observations along a flow line for 25 dates, we have reconstructed the evolution of the basal conditions prior to and during the 1982–1983 surge. The model solves the full-Stokes problem along the central flow line using the finite element method. For the 25 dates of the dataset, the basal friction parameter distribution is inferred using the inverse method proposed by Arthern and Gudmundsson (2010. This method is here slightly modified by incorporating a regularisation term in the cost function to avoid short wavelength changes in the friction parameter. Our results indicate that dramatic changes in the basal conditions occurred between 1973 to 1983. Prior to the surge, periodic changes can be observed between winter and summer, with a regular increase of the sliding from 1973 to 1982. During the surge, the basal friction decreased dramatically and an area of very low friction moved from the upper part of the glacier to its terminus. Using a more complex friction law, these changes in basal sliding are then interpreted in terms of basal water pressure. Our results support that dramatic changes took place in the subglacial drainage system of Variegated Glacier, moving from a relatively efficient drainage system prior to the surge to an inefficient one during the surge. By reconstructing the water pressure evolution at the base of the glacier it is possible to propose a scenario for the hydrological history leading to the occurrence of a surge.

  4. Electromotive force analysis of current transformer during lightning surge inflow using Fourier series expansion

    Directory of Open Access Journals (Sweden)

    Youngsun Kim

    2017-05-01

    Full Text Available The most common structure used for current transformers (CTs consists of secondary windings around a ferromagnetic core past the primary current being measured. A CT used as a surge protection device (SPD may experience large inrushes of current, like surges. However, when a large current flows into the primary winding, measuring the magnitude of the current is difficult because the ferromagnetic core becomes magnetically saturated. Several approaches to reduce the saturation effect are described in the literature. A Rogowski coil is representative of several devices that measure large currents. It is an electrical device that measures alternating current (AC or high-frequency current. However, such devices are very expensive in application. In addition, the volume of a CT must be increased to measure sufficiently large currents, but for installation spaces that are too small, other methods must be used. To solve this problem, it is necessary to analyze the magnetic field and electromotive force (EMF characteristics when designing a CT. Thus, we proposed an analysis method for the CT under an inrush current using the time-domain finite element method (TDFEM. The input source current of a surge waveform is expanded by a Fourier series to obtain an instantaneous value. An FEM model of the device is derived in a two-dimensional system and coupled with EMF circuits. The time-derivative term in the differential equation is solved in each time step by the finite difference method. It is concluded that the proposed algorithm is useful for analyzing CT characteristics, including the field distribution. Consequently, the proposed algorithm yields a reference for obtaining the effects of design parameters and magnetic materials for special shapes and sizes before the CT is designed and manufactured.

  5. Challenges in Downscaling Surge and Flooding Predictions Associated with Major Coastal Storm Events

    Science.gov (United States)

    Bowman, M. J.

    2015-12-01

    Coastal zone managers, elected officials and emergency planning personnel are continually seeking more reliable estimates of storm surge and inundation for better land use planning, the design, construction and operation of coastal defense systems, resilience evaluation and evacuation planning. Customers of modern regional weather and storm surge prediction models demand high resolution, speed, accuracy, with informative, interactive graphics and easy evaluation of potentially dangerous threats to life and property. These challenges continue to get more difficult as the demand for street-scale and even building-scale predictions increase. Fluctuations in sub-grid-scale wind and water velocities can lead to unsuspected, unanticipated and dangerous flooding in local communities. But how reliable and believable are these models given the inherent natural uncertainty and chaotic behavior in the underlying dynamics, which can lead to rapid and unexpected perturbations in the wind and pressure fields and hence coastal flooding? Traditionally this uncertainty has been quantified by the use of the ensemble method, where a suite of model runs are made with varying physics and initial conditions, presenting the mean and variance of the ensemble as the best metrics possible. But this assumes that each component is equally possible and is statistically independent of the others. But this is rarely true, although the "safety in numbers" approach is comforting to those faced with life and death decisions. An example of the ensemble method is presented for the trajectory of superstorm Sandy's storm center as it approached coastal New Jersey. If one were to ask the question "was Sandy a worst case scenario", the answer would be "no: small variations in the timing (vis-à-vis tide phase) and location of landfall could easily have led to an additional surge of +50 cm at The Battery NY with even more catastrophic consequences to those experienced".

  6. Milk Leptin Surge and Biological Rhythms of Leptin and Other Regulatory Proteins in Breastmilk

    Science.gov (United States)

    Nozhenko, Yuriy; Asnani-Kishnani, Madhu; Rodríguez, Ana M.; Palou, Andreu

    2015-01-01

    A significant number of chronic diseases are linked to perinatal nutrition, and prevention may be associated to naturally occurring components of breast milk. One key hormone in breast milk is leptin, related with the protection from obesity in the adulthood, thus knowing its changes through the day or lactation is crucial. We aimed to investigate the daily rhythms in the milk levels of leptin, together with other two related hormones, ghrelin and adiponectin, during lactation (days 5, 10 and 15) in rat dams, and the relation with morphometric parameters (dams and pups). Summarizing the main results, the existence of biological rhythms, but not daily and maybe circasemidian, was confirmed for the three hormones at the earliest period of lactation. The correlations performed generally showed a possible dependence of milk hormone levels on plasma levels at the early phase of lactation, while with the progression of lactation this dependence may fade and the hormone levels are suggested to be more dependent on mammary gland production/maturation. There was also a correlation between milk leptin and adiponectin levels, especially in the first half of lactation, suggesting a possible parallel regulation. Interestingly, we describe a milk leptin surge around the mid of lactation (at day 10) which may be related with pup´s growth (males and females) and with the well-known (in the literature) plasma leptin surge in pups. All this knowledge may be crucial for future applications in the development of formula milk and in relation with the role of leptin surge during lactation. PMID:26680765

  7. Milk Leptin Surge and Biological Rhythms of Leptin and Other Regulatory Proteins in Breastmilk.

    Directory of Open Access Journals (Sweden)

    Yuriy Nozhenko

    Full Text Available A significant number of chronic diseases are linked to perinatal nutrition, and prevention may be associated to naturally occurring components of breast milk. One key hormone in breast milk is leptin, related with the protection from obesity in the adulthood, thus knowing its changes through the day or lactation is crucial. We aimed to investigate the daily rhythms in the milk levels of leptin, together with other two related hormones, ghrelin and adiponectin, during lactation (days 5, 10 and 15 in rat dams, and the relation with morphometric parameters (dams and pups. Summarizing the main results, the existence of biological rhythms, but not daily and maybe circasemidian, was confirmed for the three hormones at the earliest period of lactation. The correlations performed generally showed a possible dependence of milk hormone levels on plasma levels at the early phase of lactation, while with the progression of lactation this dependence may fade and the hormone levels are suggested to be more dependent on mammary gland production/maturation. There was also a correlation between milk leptin and adiponectin levels, especially in the first half of lactation, suggesting a possible parallel regulation. Interestingly, we describe a milk leptin surge around the mid of lactation (at day 10 which may be related with pup's growth (males and females and with the well-known (in the literature plasma leptin surge in pups. All this knowledge may be crucial for future applications in the development of formula milk and in relation with the role of leptin surge during lactation.

  8. Electromotive force analysis of current transformer during lightning surge inflow using Fourier series expansion

    Science.gov (United States)

    Kim, Youngsun

    2017-05-01

    The most common structure used for current transformers (CTs) consists of secondary windings around a ferromagnetic core past the primary current being measured. A CT used as a surge protection device (SPD) may experience large inrushes of current, like surges. However, when a large current flows into the primary winding, measuring the magnitude of the current is difficult because the ferromagnetic core becomes magnetically saturated. Several approaches to reduce the saturation effect are described in the literature. A Rogowski coil is representative of several devices that measure large currents. It is an electrical device that measures alternating current (AC) or high-frequency current. However, such devices are very expensive in application. In addition, the volume of a CT must be increased to measure sufficiently large currents, but for installation spaces that are too small, other methods must be used. To solve this problem, it is necessary to analyze the magnetic field and electromotive force (EMF) characteristics when designing a CT. Thus, we proposed an analysis method for the CT under an inrush current using the time-domain finite element method (TDFEM). The input source current of a surge waveform is expanded by a Fourier series to obtain an instantaneous value. An FEM model of the device is derived in a two-dimensional system and coupled with EMF circuits. The time-derivative term in the differential equation is solved in each time step by the finite difference method. It is concluded that the proposed algorithm is useful for analyzing CT characteristics, including the field distribution. Consequently, the proposed algorithm yields a reference for obtaining the effects of design parameters and magnetic materials for special shapes and sizes before the CT is designed and manufactured.

  9. Research Resource: Preovulatory LH Surge Effects on Follicular Theca and Granulosa Transcriptomes

    Science.gov (United States)

    Gunewardena, Sumedha; Hong, Xiaoman; Spitschak, Marion; Baufeld, Anja

    2013-01-01

    The molecular mechanisms that regulate the pivotal transformation processes observed in the follicular wall following the preovulatory LH surge, are still not established, particularly for cells of the thecal layer. To elucidate thecal cell (TC) and granulosa cell (GC) type-specific biologic functions and signaling pathways, large dominant bovine follicles were collected before and 21 hours after an exogenous GnRH-induced LH surge. Antral GCs (aGCs; aspirated by follicular puncture) and membrane-associated GCs (mGCs; scraped from the follicular wall) were compared with TC expression profiles determined by mRNA microarrays. Of the approximately 11 000 total genes expressed in the periovulatory follicle, only 2% of thecal vs 25% of the granulosa genes changed in response to the LH surge. The majority of the 203 LH-regulated thecal genes were also LH regulated in GCs, leaving a total of 57 genes as LH-regulated TC-specific genes. Of the 57 thecal-specific LH-regulated genes, 74% were down-regulated including CYP17A1 and NR5A1, whereas most other genes are being identified for the first time within theca. Many of the newly identified up-regulated thecal genes (eg, PTX3, RND3, PPP4R4) were also up-regulated in granulosa. Minimal expression differences were observed between aGCs and mGCs; however, transcripts encoding extracellular proteins (NID2) and matrix modulators (ADAMTS1, SASH1) dominated these differences. We also identified large numbers of unknown LH-regulated GC genes and discuss their putative roles in ovarian function. This Research Resource provides an easy-to-access global evaluation of LH regulation in TCs and GCs that implicates numerous molecular pathways heretofore unknown within the follicle. PMID:23716604

  10. The Dorsomedial Suprachiasmatic Nucleus Times Circadian Expression of Kiss1 and the Luteinizing Hormone Surge

    Science.gov (United States)

    Smarr, Benjamin L.; Morris, Emma

    2012-01-01

    Ovulation in mammals is gated by a master circadian clock in the suprachiasmatic nucleus (SCN). GnRH neurons represent the converging pathway through which the brain triggers ovulation, but precisely how the SCN times GnRH neurons is unknown. We tested the hypothesis that neurons expressing kisspeptin, a neuropeptide coded by the Kiss1 gene and necessary for the activation of GnRH cells during ovulation, represent a relay station for circadian information that times ovulation. We first show that the circadian increase of Kiss1 expression, as well as the activation of GnRH cells, relies on intact ipsilateral neural input from the SCN. Second, by desynchronizing the dorsomedial (dm) and ventrolateral (vl) subregions of the SCN, we show that a clock residing in the dmSCN acts independently of the light-dark cycle, and the vlSCN, to time Kiss1 expression in the anteroventral periventricular nucleus of the hypothalamus and that this rhythm is always in phase with the LH surge. In addition, we show that although the timing of the LH surge is governed by the dmSCN, its amplitude likely depends on the phase coherence between the vlSCN and dmSCN. Our results suggest that whereas dmSCN neuronal oscillators are sufficient to time the LH surge through input to kisspeptin cells in the anteroventral periventricular nucleus of the hypothalamus, the phase coherence among dmSCN, vlSCN, and extra-SCN oscillators is critical for shaping it. They also suggest that female reproductive disorders associated with nocturnal shift work could emerge from the desynchronization between subregional oscillators within the master circadian clock. PMID:22454148

  11. Storm-surge flooding on the Yukon-Kuskokwim Delta, Alaska

    Science.gov (United States)

    Terenzi, John; Ely, Craig R.; Jorgenson, M. Torre

    2014-01-01

    Coastal regions of Alaska are regularly affected by intense storms of ocean origin, the frequency and intensity of which are expected to increase as a result of global climate change. The Yukon-Kuskokwim Delta (YKD), situated in western Alaska on the eastern edge of the Bering Sea, is one of the largest deltaic systems in North America. Its low relief makes it especially susceptible to storm-driven flood tides and increases in sea level. Little information exists on the extent of flooding caused by storm surges in western Alaska and its effects on salinization, shoreline erosion, permafrost thaw, vegetation, wildlife, and the subsistence-based economy. In this paper, we summarize storm flooding events in the Bering Sea region of western Alaska during 1913 – 2011 and map both the extent of inland flooding caused by autumn storms on the central YKD, using Radarsat-1 and MODIS satellite imagery, and the drift lines, using high-resolution IKONOS satellite imagery and field surveys. The largest storm surges occurred in autumn and were associated with high tides and strong (> 65 km hr-1) southwest winds. Maximum inland extent of flooding from storm surges was 30.3 km in 2005, 27.4 km in 2006, and 32.3 km in 2011, with total flood area covering 47.1%, 32.5%, and 39.4% of the 6730 km2 study area, respectively. Peak stages for the 2005 and 2011 storms were 3.1 m and 3.3 m above mean sea level, respectively—almost as high as the 3.5 m amsl elevation estimated for the largest storm observed (in November 1974). Several historically abandoned village sites lie within the area of inundation of the largest flood events. With projected sea level rise, large storms are expected to become more frequent and cover larger areas, with deleterious effects on freshwater ponds, non-saline habitats, permafrost, and landscapes used by nesting birds and local people.

  12. Effect of Hospital Staff Surge Capacity on Preparedness for a Conventional Mass Casualty Event

    Science.gov (United States)

    Welzel, Tyson B.; Koenig, Kristi L.; Bey, Tareg; Visser, Errol

    2010-01-01

    Objectives: To assess current medical staffing levels within the Hospital Referral System in the City of Cape Town Metropolitan Municipality, South Africa, and analyze the surge capacity needs to prepare for the potential of a conventional mass casualty incident during a planned mass gathering. Methods: Query of all available medical databases of both state employees and private medical personnel within the greater Cape Town area to determine current staffing levels and distribution of personnel across public and private domains. Analysis of the adequacy of available staff to manage a mass casualty incident. Results: There are 594 advanced pre-hospital personnel in Cape Town (17/100,000 population) and 142 basic pre-hospital personnel (4.6/100,000). The total number of hospital and clinic-based medical practitioners is 3097 (88.6/100,000), consisting of 1914 general physicians; 54.7/100,000 and 1183 specialist physicians; 33.8/100,000. Vacancy rates for all medical practitioners range from 23.5% to 25.5%. This includes: nursing post vacancies (26%), basic emergency care practitioners (39.3%), advanced emergency care personnel (66.8%), pharmacy assistants (42.6%), and pharmacists (33.1%). Conclusion: There are sufficient numbers and types of personnel to provide the expected ordinary healthcare needs at mass gathering sites in Cape Town; however, qualified staff are likely insufficient to manage a concurrent mass casualty event. Considering that adequate correctly skilled and trained staff form the backbone of disaster surge capacity, it appears that Cape Town is currently under resourced to manage a mass casualty event. With the increasing size and frequency of mass gathering events worldwide, adequate disaster surge capacity is an issue of global relevance. PMID:20823971

  13. Effect of Hospital Staff Surge Capacity on Preparedness for a Conventional Mass Casualty Event

    Directory of Open Access Journals (Sweden)

    Welzel, Tyson B MD

    2010-05-01

    Full Text Available OBJECTIVES: To assess current medical staffing levels within the Hospital Referral System in the City of Cape Town Metropolitan Municipality, South Africa, and analyze the surge capacity needs to prepare for the potential of a conventional mass casualty incident during a planned mass gathering.METHODS: Query of all available medical databases of both state employees and private medical personnel within the greater Cape Town area to determine current staffing levels and distribution of personnel across public and private domains. Analysis of the adequacy of available staff to manage a mass casualty incident.RESULTS: There are 594 advanced pre-hospital personnel in Cape Town (17/100,000 population and 142 basic pre-hospital personnel (4.6/100,000. The total number of hospital and clinic-based medical practitioners is 3097 (88.6/100,000, consisting of 1914 general physicians; 54.7/100,000 and 1183 specialist physicians; 33.8/100,000. Vacancy rates for all medical practitioners range from 23.5% to 25.5%. This includes: nursing post vacancies (26%, basic emergency care practitioners (39.3%, advanced emergency care personnel (66.8%, pharmacy assistants (42.6%, and pharmacists (33.1%.CONCLUSION: There are sufficient numbers and types of personnel to provide the expected ordinary healthcare needs at mass gathering sites in Cape Town; however, qualified staff are likely insufficient to manage a concurrent mass casualty event. Considering that adequate correctly skilled and trained staff form the backbone of disaster surge capacity, it appears that Cape Town is currently under resourced to manage a mass casualty event. With the increasing size and frequency of mass gathering events worldwide, adequate disaster surge capacity is an issue of global relevance. [West J Emerg Med. 2010; 11(2:189-196.

  14. Experimental study on cyclic steps formed by surge-type turbidity currents

    Science.gov (United States)

    Yokokawa, M.; Shozakai, D.; Higuchi, H.; Hughes Clarke, J. E.; Izumi, N.

    2015-12-01

    Field observations of turbidity currents and seabed topography on the Squamish delta in Howe Sound, British Columbia, Canada have been undertaken which found bedwaves actively migrating in the upstream direction in channels formed on the prodelta slope (Hughes Clarke et al., 2012a; 2012b; 2014; Figure 1). Their topography and behaviour suggest that they are cyclic steps formed by the surge-type turbidity currents. There has been no experimental study to investigate the formative conditions of cyclic steps by the surge-type turbidity currents. We did preliminary experiments on the formation of cyclic steps due to the multiple surge-type density currents, and compare the morphology of the steps with those of Squamish delta. The experiments had been performed at Osaka Institute of Technology. A flume, which is 3.6 m long, 0.3 m deep and 2 cm wide, was submerged into a larger flume, which is 4 m long, 0.4 m deep and 8 cm wide, filled with water. Mixture of salt water (1.18 g/cm3) and plastic particles (1.5 g/cm3, 0.1-0.18 mm in diameter) poured into the upstream end of the inner flume by hand using a funnel. For the example introduced here, the slope of the outer flume was 1.5 degrees, and the mixtures' whole weight and volumetric concentration ranged from 310 g (3.23 vol.%) to 510 g (8.16 vol.%). These mixtures were poured 105 times, and the thickness of the deposits was measured every 50 cm by photographs. As a result, two mounds (steps) were formed ultimately, which are moving toward upstream direction. Wavelengths are 80 cm and 120 cm respectively. The two kinds of flow depth were measured from photograph, such as the whole thickness of the flow, and the thickness of the lower high-density layer. Calculating the wave steepness and non-dimensional wave number, it turns out that those values using the thickness of the lower high-density layer fall into the region very close to the Squamish data that assuming the flow depth as 0.5 m. This could lead the following

  15. Lightning Surge Analysis for 500-kV Transmission Lines using Grounding Model with Dynamic Characteristics

    Science.gov (United States)

    Yasuda, Yoh; Kondo, Shuhei; Hara, Takehisa; Ikeda, Keiichi; Sonoi, Yasuo; Furuoka, Yoshihiro

    It is well known that grounding resistance under huge lightning current injection has current-dependent characteristics, whose mathematical model was already proposed by Liew and Darveniza in 1974. In this paper, where our final goal is reasonable design for lightning protection of 500-kV transmission tower, we adopt the dynamic grounding-resistance model to MODELS-ATP simulation. The effect of the model for the lightning surge analysis on 500-kV transmission line systems is discussed in detail.

  16. Recurrence intervals for the closure of the Dutch Maeslant surge barrier

    Science.gov (United States)

    van den Brink, Henk W.; de Goederen, Sacha

    2017-09-01

    The Dutch Maeslant Barrier, a movable surge barrier in the mouth of the river Rhine, closes when there is a surge in the North Sea and the water level in the river at Rotterdam exceeds 3 m above mean sea level. An important aspect of the failure probability is that the barrier might get damaged during a closure and that, within the time needed for repair, a second critical storm surge may occur. With an estimated closure frequency of once in 10 years, the question of how often the barrier has to be closed twice within one month arises.Instead of tackling this problem by the application of statistical models on the (short) observational series, we solve the problem by combining the surge model WAQUA/DCSMv5 with the output of all seasonal forecasts of the European Centre of Medium-Range Weather Forecasting (ECMWF) in the period 1981-2015, whose combination cumulates in a pseudo-observational series of more than 6000 years.We show that the Poisson process model leads to wrong results as it neglects the temporal correlations that are present on daily, weekly and monthly timescales.By counting the number of double events over a threshold of 2.5 m and assuming that the number of events is exponentially related to the threshold, it is found that two closures occur on average once in 150 years within a month, and once in 330 years within a week. The large uncertainty in these recurrence intervals of more than a factor of two is caused by the sensitivity of the results to the Gumbel parameters of the observed record, which are used for bias correction.Sea level rise has a significant impact on the recurrence time for both single and double closures. The recurrence time of single closures doubles with every 18 cm mean sea level rise (assuming that other influences remain unchanged) and double closures double with every 10 cm rise. This implies a 3-14 times higher probability of a double closure for a 15-40 cm sea level rise in 2050 (according to the KNMI climate scenarios).

  17. Influence of Surge Motion on the Probability of Parametric Roll in a Stationary Sea State

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Vidic-Perunovic, Jelena; Pedersen, Preben Terndrup

    2007-01-01

    A typical parametric roll scenario for a ship in head waves implies that the roll motion is coupled with vertical motion of the vessel. The added resistance of the ship is increased when the bow pitches down in a wave crest. As a consequence, the ship speed is slowed down and, hence, the roll res...... resonance condition might be changed. In an attempt to study the influence of this speed variation in waves on parametric roll, the procedure for estimation of probability of parametric roll by Jensen and Pedersen (2006) has been extended to account for the surge motion of the vessel....

  18. Effects of pulsation dampers in piping systems in terms of pressure surge reduction

    Energy Technology Data Exchange (ETDEWEB)

    Keller, C. [AREVA NP GmbH (Germany)

    2010-05-15

    Pulsation dampers working with a compressible gas volume have the capability of reducing pressure surges in piping systems if they are properly dimensioned and positioned. This is also valid for piping systems with high pressure levels. Even if they show promising pressure peak mitigation effects the application of pulsation dampers in nuclear power plants will still remain on an exceptional basis. However with the help of computer simulations it is possible to predict the effect of such devices much more precisely then in the past. This is the reason why the application of pulsation dampers for special cases should be considered as possibility. (orig.)

  19. Effect of preemptive weld overlay on residual stress of repaired weldment in surge nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Chang Young; Song, Tae Kwang; Bae, Hong Yeol; Chun, Yun Bae; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of); Lee, Kyoung Soo; Park, Chi Yong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2008-07-01

    In the welding process, weldments usually include repair weld during the manufacturing process. Repair welds is supposed to cause strong tensile residual stress. Moreover weldments, usually made by Alloy 82/182, is susceptible to PWSCC. Therefore, mitigation of welding residual stress in weldments is important for reliable operating. PWOL is one of the methods for mitigation and verified for over twenty years. In this paper, residual stress distribution of repaired weldments and the effect of PWOL on mitigation is examined for surge nozzle.

  20. Joint projections of sea level and storm surge using a flood index

    Science.gov (United States)

    Little, C. M.; Lin, N.; Horton, R. M.; Kopp, R. E.; Oppenheimer, M.

    2016-02-01

    Capturing the joint influence of sea level rise (SLR) and tropical cyclones (TCs) on future coastal flood risk poses significant challenges. To address these difficulties, Little et al. (2015) use a proxy of tropical cyclone activity and a probabilistic flood index that aggregates flood height and duration over a wide area (the US East and Gulf coasts). This technique illuminates the individual impacts of TCs and SLR and their correlation across different coupled climate models. By 2080-2099, changes in the flood index relative to 1986-2005 are substantial and positively skewed: a 10th-90th percentile range of 35-350x higher for a high-end business-as-usual emissions scenario (see figure). This aggregated flood index: 1) is a means to consistently combine TC-driven storm surges and SLR; 2) provides a more robust description of historical surge-climate relationships than is available at any one location; and 3) allows the incorporation of a larger climate model ensemble - which is critical to uncertainty characterization. It does not provide a local view of the complete spectrum of flood severity (i.e. return curves). However, alternate techniques that provide localized return curves (e.g. Lin et al., 2012) are computationally intensive, limiting the set of large-scale climate models that can be incorporated, and require several linked statistical and dynamical models, each with structural uncertainties that are difficult to quantify. Here, we present the results of Little et al. (2015) along with: 1) alternate formulations of the flood index; 2) strategies to localize the flood index; and 3) a comparison of flood index projections to those provided by model-based return curves. We look to this interdisciplinary audience for feedback on the advantages and disadvantages of each tool for coastal planning and decision-making. Lin, N., K. Emanuel, M. Oppenheimer, and E. Vanmarcke, 2012: Physically based assessment of hurricane surge threat under climate change. Nature