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Sample records for surge arresters eglas

  1. Specific Considerations on IEC Standardization of Externally Gapped Line Surge Arresters (EGLAs)

    Science.gov (United States)

    Ishizaki, Yoshihiro; Tsuge, Kenji; Kobayashi, Misao; Izumi, Kunikazu; Kawamura, Tatsuo

    The application of externally gapped line surge arresters (EGLAs), which have been developed and established in Japan, is now expanding into many countries. Therefore, the maintenance team 4 (MT4) in the international electrotechnical commission (IEC) technical committee 37 (TC37) for surge arresters advances the standardization works to specify the minimum criteria for requirements and testing methods of EGLAs. EGLAs are effective lightning protection of overhead transmission lines, and have unique required performances originated from the external series gap. The unique required performances of EGLA are insulation coordination performance of EGLA sparkover voltage for lightning overvoltage with the insulator assembly to be protected, withstand voltage performance for switching surge overvoltage and TOV, and follow current interruption performance. This paper discusses the specific issues to be considered for the standardization, such as classification of lightning discharge current rating and a test procedure for follow current interruption performance, based on the Japanese technology through more than twenty years of experience with a large numbers of EGLAs in 22kV to 500kV systems.

  2. Comments on metal oxide surge arresters surges energy absorption capacity

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, M.L.B. [Escola Federal de Engenharia de Itajuba, Minas Gerais (Brazil); Zanetta, L.C. Jr. [E. Politecnica Univ. de Sao Paulo, Sao Paulo (Brazil)

    1996-12-31

    This paper presents an approach to determine the energy absorption capacity of metal oxide surge arrester resistors. The proposed approach deals with the discharge current peak versus discharge current time relation. A testing method and a statistical evaluation are proposed. After determining the discharge current withstanding limit of the tested metal oxide resistors, the prospective energy absorption capacity limit is computed. Finally, comments on the obtained results are presented.

  3. Electrothermal model for complete metal-oxide surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Costa, E. Guedes da; Naidu, S.R. [UFPB, Dept. of Electrical Engineering, Campina Grande, PB (Brazil); Lima, A. Guedes de [CEFET-PB, Dept. of Mechanical Engineering, Joao Pessoa, PB (Brazil)

    2001-01-01

    A computational, electrothermal model for a complete metal-oxide surge arrester based on the implicit form of the finite-differences method is presented. The model is used to calculate the cooling curve after the application of overvoltages and the temperature variations during standard test. The model has been checked against experiments carried out on a test section and a complete surge arrester and the behaviour of a hypothetical surge arrester during standard tests simulated. (Author)

  4. Changing the guard: Polymer replaces porcelain for surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Skytt, T.; Gleimar, H. E. G.

    2002-07-01

    Surge arresters are safety devices which quickly and effectively limit the over voltages that can arise in transmission networks following lightning, switching and other transient events. The earliest forms of overvoltage protection, a simple air gap between electrodes, have long since been replaced by a new generation of gapless arresters with series-connected, non-linear zinc oxide varistors contained in a porcelain housing. Now these porcelain type surge arresters are being replaced by a new type, called PEXLIM (Polymeric EXcellent LIMiter), which uses the same block of zinc oxide as the porcelain type, but its housing is made of silicon rubber, a polymer. The new lightweight insulation material shows a number of properties superior to the porcelain, such as enhanced product safety and ease of handling. It is also more durable, resilient, yet solid and compact, water-repellent, lightweight, resistant to aging or light or ultra-violet radiation, as well as fire, has good electrical properties, and is environmentally friendly since it does not contain any substances harmful to the environment. These properties make this new type of surge arrester highly suitable for use in earthquake-prone areas; it can also replace more expensive and maintenance-intensive equipment. Having successfully broken into the lower voltage systems, these new type of surge arresters are now rapidly gaining ground at the higher voltage levels. ABB, the developer of PEXLIM, has already supplied these arresters to North America for use in an 800-kV grid. As further proof of its growing popularity, last year PEXLIM made up over half of the surge arrester production for applications up to and including 245 kV. 1 tab., 6 figs.

  5. Hybrid simulation of metal oxide surge-arrester thermal behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L.; Raghuveer, M.R. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Electrical and Computer Engineering

    1996-01-01

    A finite-difference-based technique for simulating the thermal behaviour of a metal oxide surge arrester (MOSA) was described. The improved hybrid thermal modelling technique was claimed to accurately represent heat-transfer modes. Fin theory was used to represent arrester sheds. The proposed model, which relies on simple measurements at the arrester terminals, yields the temporal variation of temperature in a MOSA in both the axial and radial direction. The thermal behaviour of a MOSA under steady-state and transient conditions can be simulated using such a model under different environmental conditions. The accuracy of the modelling technique was demonstrated experimentally by measurements conducted on an arrester. 15 refs., 7 figs.

  6. Performance of metal oxide gapless surge arresters for HVDC systems

    Energy Technology Data Exchange (ETDEWEB)

    Diseko, N.L.

    1990-09-01

    An examination of the electrical stresses which may be imposed upon metal oxide surge arresters in a dc converter station is undertaken by means of simulation of the dc system and associated ac systems in the time domain using a digital computer program. Detailed models of a dc link are developed for temporary overvoltage stresses and steep front stresses. The most critical stresses for each type of dc station arrester due to converter faults and converter malfunctions are identified. The energy stresses were generally determined to be dependent on the converter control and protection strategies adopted during the faults. The arrester energy stresses for faults on both the line side and valve side busses of the converter transformer were determined to be sensitive to the instant of fault application and the duration of the fault. The arrester stresses for ac bus faults were analyzed in detail to determine their statistical distribution relative to the point on wave at which the fault occurred in each affected phase, and to the instant of fault clearance in each phase. Generally, the highest stresses occur for sequential fault occurrence in the phases compared with simultaneous faults. The studies indicate that the stresses in the arresters in a dc pile experiencing the worst duty depend on the number of arresters represented. Modelling only one arrester of a series-connected group does not provide correct results when the fault condition imposes duty on more than one of the arresters in the group. The study also indicates that the highest stresses do not necessarily occur in the single arrester connected across the valve with the highest prospective overvoltage. Hence the capability to represent all valve arresters within one pole is necessary when determining the most onerous stresses. 11 refs., 79 figs., 28 tabs.

  7. Effectiveness of installing two pairs of distribution surge arresters in parallel

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Hitoshi; Asakawa, Akira; Yokoyama, Shigeru [Central Research Institute of Electric Power Industry (Japan); Nakada, Kazuo [Hokurika Electric Power Co. (Japan)

    1999-07-01

    Lightning strokes with a large amount of energy sometimes occur on the Sea of Japan coast in winter. Winter lightning often damages overhead power distribution lines, in particular, those supplying power to high structures located in mountainous areas. We have investigated that the ratio of surge arrester outages with respect to all damaged installations on such power distribution lines is largest at approximately 50%. We have examined the effectiveness of installing two pairs of surge arresters in parallel on a single pole as a method for preventing distribution surge arrester outages experimentally. We have clarified that to install surge arresters in parallel is effective in reducing the energy absorbed by surge arresters if these surge arresters have almost the same discharge voltage and voltage-current characteristics. (author)

  8. 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.

  9. Recent Trends of Technology of Zinc-Oxide Surge Arrester for Electric Power System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.S.; Kim, K.U.; Cho, H.G. [Korea Electrotechnology Research Institute (Korea); Park, T.G. [Changwon National University (Korea); Park, S.H. [KEPCO (Korea)

    1999-05-01

    Metal-oxide surge arresters were developed in the late 1970s, and were immediately recognized as significant breakthrough in over-voltage protection of power system. Work was continued throughout the world on the design, development and application of metal-oxide surge arresters. (author). 6 refs., 1 fig., 6 tabs.

  10. Brazilian production development of class 2 polymeric surge arresters for transmission line application

    Energy Technology Data Exchange (ETDEWEB)

    Dellallibera, Adriano A. [Industria Eletromecanica Balestro, Mogi Mirim, SP (Brazil)], E-mail: adrianoad@balestro.com; Andrade, Antonio Donizetti de; Bezerra, Ana Cristina Guara; Duarte, Jose Vicente Pereira; Gois, Paulo Marcio Batista; Markiewicz, Rubens Leopoldo [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)], Emails: andonize@cemig.com.br, anacris@cemig.com.br, vicente@cemig.com.br, pgois@cemig.com.br, rlmark@cemig.com.br

    2007-07-01

    This paper shows the steeps of Brazilian class 2 ZnO lightning surge arrester development and production, aiming to attend the goal of CEMIG transmission lines performance improvement against lightning discharges action. The description of CEMIG transmission lines performance, before and after the ZnO lightning arresters installation, the necessity of use of ZnO lightning surge arrester, the prototypes manufacture, tests, problems and solutions are presented. (author)

  11. Application and Analysis for Surge Arrester on Lightning Protection of Distribution Network

    Directory of Open Access Journals (Sweden)

    Wang Daxing

    2016-01-01

    Full Text Available In order to effectively reduce lightning stroke outage rate, effect of lightning protection with surge arrester on transmission line has been generally acknowledged relative to other lightning protection measures. This article introduces in such aspects as the working principle of line surge arrester and effect of lightning protection, and also explores application for lightning arrester of distribution network to achieve difference lightning protection and improve the lightning protection performance of distribution network.

  12. Application and Analysis for Surge Arrester on Lightning Protection of Distribution Network

    Directory of Open Access Journals (Sweden)

    Wang Daxing

    2015-01-01

    Full Text Available In order to effectively reduce lightning stroke outage rate, effect of lightning protection with surge arrester on transmission line has been generally acknowledged relative to other lightning protection measures. This article introduces in such aspects as the working principle of line surge arrester and effect of lightning protection, and also explores application for lightning arrester of distribution network to achieve difference lightning protection and improve the lightning protection performance of distribution network.

  13. Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations

    Science.gov (United States)

    Shirakawa, Shingo; Kobayashi, Takayuki; Matsushita, Yoshinao; Sakai, Takehisa; Suzuki, Hironori; Ozaki, Yuzo

    Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

  14. Development of an Electro–Thermal Model for ZnO Surge Arrester Under Contamination

    Directory of Open Access Journals (Sweden)

    E. Melgoza–Vázquez

    2010-01-01

    Full Text Available An electro–thermal model for a Zinc Oxide (ZnO surge arrester under contamination tests is presented. The model is based in three sub–models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacitance and a non–linear resistor. The thermal model takes into account the heat generated and dissipated by the column of varistors and its surroundings. The contamination is represented by a dynamic impedance obtained from measurements in the arrester column during contamination tests. The full model is validated by calculating the temperature increase during contamination tests carried out in a two units ZnO surge arrester, class 190 kV. Finally, the results of the effect of several design and construction parameters in the voltage and temperature distribution in the arrester columns during contamination tests are presented.

  15. A new on-line leakage current monitoring system of ZnO surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok-Hee [Research Center for Next-Generation High Voltage and Power Technology, Inha University, 253 Yonghyun-dong, Nam-ku, Incheon 402-751 (Korea, Republic of)]. E-mail: bhlee@inha.ac.kr; Kang, Sung-Man [Research Center for Next-Generation High Voltage and Power Technology, Inha University, 253 Yonghyun-dong, Nam-ku, Incheon 402-751 (Korea, Republic of)

    2005-05-15

    This paper presents a new on-line leakage current monitoring system of zinc oxide (ZnO) surge arresters. To effectively diagnose the deterioration of ZnO surge arresters, a new algorithm and on-line leakage current detection device, which uses the time-delay addition method, for discriminating the resistive and capacitive currents was developed to use in the aging test and durability evaluation for ZnO arrester blocks. A computer-based measurement system of the resistive leakage current, the on-line monitoring device can detect accurately the leakage currents flowing through ZnO surge arresters for power frequency ac applied voltages. The proposed on-line leakage current monitoring device of ZnO surge arresters is more highly sensitive and gives more linear response than the existing devices using the detection method of the third harmonic leakage currents. Therefore, the proposed leakage current monitoring device can be useful for predicting the defects and performance deterioration of ZnO surge arresters in power system applications.

  16. 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)

  17. Co-ordination of spark-gap protection with zinc-oxide surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, A.; German, D.M.; Waters, R.T. [Cardiff Univ., School of Engineering, Cardiff (United Kingdom); Abdul-Malek, Z. [University of Technology (Malaysia)

    2001-01-01

    Zinc-oxide (ZnO) surge arresters are now well established as a very efficient and reliable form of overvoltage protection against both fast surges, such as those generated by lightning and gas-insulated switchgear, and high-energy surges generated by switching operations and temporary faults on the network. The addition of ZnO surge arresters to existing protection schemes reinforces the system's reliability and the security of supply. The protection characteristics of the parallel configuration formed by arresters and existing spark gaps at distribution voltages are studied. Tests on various spark-gap geometries, with and without surge arresters in parallel, have been carried out to determine breakdown characteristics, probability curves and voltage-time characteristics for different impulse shapes. It is found that the introduction of the arrester in the circuit modifies the prospective impulse which results in the shift of the breakdown characteristics towards higher voltages. A proposed circuit model, based on laboratory test data, is used to simulate such parallel configurations. Good agreement between test and simulated results is obtained. As a result of these tests, it is recommended that gap-sparkover characteristics based on short-tail (about 5{mu}s) impulses are used for insulation co-ordination. The role of parallel airgaps in preserving the arrester energy-rating limits is also discussed. (Author)

  18. 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)

  19. Effective Installations Technique of Grounding Conductors for Metal Oxide Surge Arresters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B.H.; Kang, S.M. [Inha University, Inchon (Korea); Ryu, I.S. [Korea Electric Power Corporation, Seoul (Korea)

    2002-06-01

    This paper deals with the effects of grounding conductors for metal oxide surge arresters. When surge arresters are improperly installed, the results can cause costly damage of electrical equipments. In particular, the route of surge arrester connection is very important because bends and links of leads increase the impedances to lightning surges and tend to nullify the effectiveness of a grounding conductor. Therefore, there is a need to know how effective installation of lightning surge arresters is made in order to control voltage and to absorb energy at high lightning currents. The effectiveness of a grounding conductor and 18 [kV] metal oxide distribution line arresters was experimentally investigated under the lightning and oscillatory impulse voltages. Thus, the results are as follows; (1) The induced voltage of a grounding conductor is drastically not affected by length of a connecting line, but it is very sensitive to types of grounding conductor. (2) The coaxial cable having a low characteristic impedance is suitable as a grounding conductor. (3) It is also clear from these results that bonding the metal raceway enclosing the grounding conductor to the grounding electrode is very effective because of skin effect. (4) The induced voltages of grounding conductors for the oscillatory impulse voltages are approximately twice as large as those for the lightning impulse voltages. (author). 9 refs., 12 figs., 2 tabs.

  20. 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)

  1. Lightning arrester models enabling highly accurate lightning surge analysis; Koseidona kaminari surge kaiseki wo kano ni suru hiraiki model

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, T. [Chubu Electric Power Co. Inc., Nagoya (Japan); Funabashi, T.; Hagiwara, T.; Watanabe, H. [Meidensha Corp., Tokyo (Japan)

    1998-12-28

    Introduced herein are a dynamic behavior model for lightning arresters designed for power stations and substations and a flashover model for a lightning arresting device designed for transmission, both developed by the author et al. The author et al base their zinc oxide type lightning arrester model on the conventional static V-I characteristics, and supplement them with difference in voltage between static and dynamic characteristics. The model is easily simulated using EMTP (Electromagnetic Transients Program) etc. There is good agreement between the results of calculation performed using this model and actually measured values. Lightning arresting devices for transmission have come into practical use, and their effectiveness is introduced on various occasions. For the proper application of such devices, an analysis model capable of faithfully describing the flashover characteristics of arcing horns installed in great numbers along transmission lines, and of lightning arresting devices for transmission, are required. The author et al have newly developed a flashover model for the devices and uses the model for the analysis of lightning surges. It is found that the actually measured values of discharge characteristics of lightning arresting devices for transmission agree well with the values calculated by use of the model. (NEDO)

  2. 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.

  3. A novel parameter estimation method for metal oxide surge arrester models

    Indian Academy of Sciences (India)

    Mehdi Nafar; Gevork B Gharehpetian; Taher Niknam

    2011-12-01

    Accurate modelling and exact determination of Metal Oxide (MO) surge arrester parameters are very important for arrester allocation, insulation coordination studies and systems reliability calculations. 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 Swarm Optimization (MAPSO). In the proposed algorithm, to overcome the drawback of the PSO algorithm (convergence to local optima), the inertia weight is tuned by using fuzzy rules and the cognitive and the social parameters are self-adaptively adjusted. Also, to improve the global search capability and prevent the convergence to local minima, ACO algorithm is combined to the proposed APSO algorithm. The transient models of MO surge arrester have been simulated by using ATP-EMTP. The results of simulations have been applied to the program, which is based on MAPSO algorithm and can determine the fitness and parameters of different models. The validity and the accuracy of estimated parameters of surge arrester models are assessed by comparing the predicted residual voltage with experimental results.

  4. Study of the Electric Filed Around a Metal Oxide Surge Arrester: Measurement and Simulation

    Institute of Scientific and Technical Information of China (English)

    Christodoulou C A; Spanias C A; Kontargyri V T; Gonos I F; Stathopulos I A

    2013-01-01

    The study of the electric field around a surge arrester is useful for design procedures and diagnostic tests.The current work computes the electric field around a medium voltage gapless surge arrester using 2D and 3D representation of the arrester.The 2D simulation design,which is described in IEC 60099-4 Standard,cannot include the non symmetrical parts of the arrester geometry and the test arrangement.3D simulation procedures have the advantage that takes into account these asymmetries,giving more accurate results for each measurement position.In order to confirm the suitability of the created models,the simulation results of the electric field,using the 2D and 3D edition of PC Opera,are compared with recorded measurements,which are obtained in laboratory using appropriate calibrated field meters.

  5. Parameters Calculation of ZnO Surge Arrester Models by Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    A. Bayadi

    2006-09-01

    Full Text Available This paper proposes to provide a new technique based on the genetic algorithm to obtain the best possible series of values of the parameters of the ZnO surge arresters models. The validity of the predicted parameters is then checked by comparing the results predicted 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.

  6. Reduction of the visual impact of overhead transmission line systems through utilisation of line surge arresters as lightning protection

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

    2008-01-01

    in line performance and lightning protection of the nearest substations requires thorough modelling of the new line including all electrical parameters necessary for performance evaluation under all conditions. In this paper, explicit use of line surge arresters as lightning protection on the line...... of the line and the required protection level in substations. The use of line surge arresters gives the possibility to decrease the height of towers thereby improving the visual impression of the overhead line transmission systems. However the usage of line surge arresters will, dependent upon line surge...

  7. Estimation of the Frequency of Instantaneous Voltage Drops Dependent on Arrangement of Line Surge Arresters

    Science.gov (United States)

    Kawamura, Hironao; Kozuka, Masahiro; Itamoto, Naoki; Shinjo, Kazuo; Ishii, Masaru

    Lightning faults on transmission lines often cause instantaneous voltage drops in power systems. Influences of instantaneous voltage drops become increasingly serious in high technology industries etc. As countermeasures of instantaneous voltage drops, uninterruptible power supplies (UPS) are employed. On the other hand, line surge arresters are installed on transmission lines increasingly as one of the effective countermeasures of double-circuit faults caused by lightning strokes. Additionally, the arresters are effective as one of the reduction methods for the frequency of instantaneous voltage drops. In this paper, the frequency of instantaneous voltage drops reduced by installation of line surge arresters on transmission lines is estimated by employing EMTP analysis. Also, the accuracy of the method in estimating the frequency of instantaneous voltage drops in power systems is evaluated through comparison with experience.

  8. The Anti-surge Capacity of the Surge Arresters for Information System%信息系统避雷器的抗浪涌能力

    Institute of Scientific and Technical Information of China (English)

    谭克勤

    2001-01-01

    The paper describes the basic characteristics about lightning over-voltage, the technology measures of anti-lightning, and the usage and classification of surge arresters. The paper forcus on the Anti-surge capacity of the various surge arresters.%阐述了雷电过电压的基本特性及防雷技术措施,避雷器的用途和分类,重点论述了各种信息系统避雷器的抗浪涌能力。

  9. Performance analysis of surge arrester on high voltage systems using ATP

    Energy Technology Data Exchange (ETDEWEB)

    Nallagownden, P.; Magumane, A.H. [Univ. Teknologi Petronas, Perak (Malaysia); Kanth, K.S.R. [Tenaga National Berhad (Malaysia)

    2008-07-01

    Lightning strikes are among the major factors that cause failures in electrical power systems. Phase to ground arresters are commonly installed at power transformer terminals to offer some lightning protection. However, it is important to understand the performance of metal oxide arresters under very fast transient overvoltages in order to determine the protection zone of the arrester and to achieve economical benefits. This study investigated lightning overvoltage protection in a complete three-phase scheme of a 500 KV substation. Overvoltages originated from direct lightning stroke on a phase of a real overhead line (OHL) model. The effect of the separation distance of the arrester from the transformer connected at the open end of the substations was investigated as well as the performance of the arrester for different substation configurations. In the first scenario, the connection of the arrester and transformer was done with a direct connection of an overhead line. In the second scenario, the connection of these devices was done through a cable. Both the overhead line and cable lengths were varied and the maximum overvoltages coming to the transformer were recorded. The results showed that there is a direct proportionality between overvoltages and length of the overhead line or cable. As long the length of the line or cable between the arrester and the transformer was increased, the vulnerability of the transformer to receive high overvoltages also increased. Surge overvoltages were found to be very sensitive to impedance of the line or cable. The direct connections of overhead lines between the arrester and transformer make it necessary to add some protective device. It was suggested that surge arresters should be installed every 200 meters along the overhead lines in order to ensure the safety of equipment. 12 refs., 4 tabs., 8 figs.

  10. A practical field application of surge arrester technology in a distribution system

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, P. [Monaro Electricity, Cooma, NSW (Australia)

    1995-11-01

    The Monaro Region NSW has an average isokeraunic level of between 15-25 thunderstorm days per year. The average number of lightning flashes per year in the Cooma area is 4,437. Most damage occurs during the summer period from October to March. This paper provides feedback on the results to date of a large scale surge arrester installation program on distribution transformers within Monaro Electricity. It provides a case study for examining a distribution system which has gone from being almost completely unprotected to fully protected in a short period of time and should provide important evaluations on the effectiveness of surge arrester technology. Early data from the program indicates significant reduction in operating costs and incidences of unplanned outages. The main benefit from this has been increased consumer confidence in Monaro`s distribution system reliability and the program has demonstrated the value and effectiveness of modern surge arrester protection in a distribution system. 9 tabs., 5 figs., 1 photo.

  11. Optimization of spacers placement in metal oxide surge arresters due to the thermal stability increment using genetic algorithm

    Directory of Open Access Journals (Sweden)

    Seyed Meysam Seyedbarzegar

    2015-03-01

    Full Text Available Abstract: in this paper the optimal placement of spacers in surge arrester column is presented in order to achieve temperature reduction and surge arrester thermal stability against power losses due to the overvoltage in power system. The simulation is done by using genetic algorithm in MATLAB software that it is linked by numerical analysis, i.e., Finite Element Method (FEM. First, electro thermal analysis is performed according to the IEC60099-4 standard on selected population in certain interval and, then the required data is applied to the genetic algorithm for the optimal placement of spacers. Simulation results show that the placement of spacers has great influence on surge arrester temperature variations. Finally, the optimal model of surge arrester is simulated in COMSOL software and the results of this model are compared with conventional model results.

  12. Developing the First Gapless ZnO Surge Arrester in the World

    Science.gov (United States)

    Hayashi, Masao; Kobayashi, Misao

    Metal Oxide Surge Arrester (MOSA) technology was first developed in Japan and improved. Original discovery was made by Matsushita Electric Industry Co., Ltd by a finding of some diode phenomenon. Meidensha Corporation applied it to high voltage grid system in Japan in 1975 as a reliable lightning protection device. Japanese MOSA manufactures played a leading role in world MOSA innovations and developments. The BIL has been standardized based on arrester protective characteristics. Due to MOSA, the product shift to MOSA occurred from the gapped type arresters (GTA) 35 years ago as GTA had many gap-related problems. The MOSA became a complete IEC standard (IEC60099-4-1991) taking 20 years from starting development. The MOSA now has a solid footprint in the world lightning protection space.

  13. STUDY ON SURGE ARRESTER PERFORMANCE DUE TO LIGHTNING STROKE IN 20 KV DISTRIBUTION LINES

    Directory of Open Access Journals (Sweden)

    Agung Warsito

    2012-02-01

    Full Text Available Electric energy has been transmiting from power station to end user with transmission and distribution lines.Lightning strokes are problems that occure in transmission and distribution lines and make them fault when theelectric energy were transmited. Surge Diverter or Lightning Arrester has been installing to reduce these faults.In this paper the simulation of lightning stroke and lightning arrester performance on distribution lines 20 kVwere done using EMTP (Electromagnetic Transient Program. Some parameters such us impuls voltage andincreasing voltage on distribution line was inverstigated. As case study in this simulation, Mojosongo 1 mainfeeder 20 kV three phase lines were used.The simulation results show that the lightning stroke 20 kA in By1-61-61E-84-9I on S phase at 0,1 ms, makevoltage on S phase was increased about 1,3054 MV. For R phase and T phase will increase of induced voltagewere 0.79539 MV and 0.80484 MV. We also show the performance of MOV Arrester (Metal Oxide Varistor inovercoming lightning stroke trouble, where arrester can decrease voltage up to 15.198 kV on S phase, while atR phase and T phase arrester can decrease voltage up to 11.375 kV and 13.616 kV.

  14. Analysis on Lighting Withstand Characteristics of Polymeric ZnO Surge Arrester for Transmission Line against Lightning Overvoltages

    Energy Technology Data Exchange (ETDEWEB)

    Han, S.W.; Cho, H.G. [Korea Electrotechnology Research Institute, Changwon (Korea); He, J.L. [Tsinghua University, Beijing (Switzerland)

    2000-02-01

    The purpose of this study is to discuss the lightning withstand levels (LWLs) of two 110 kV transmission lines before and after line arresters made with polymeric housing are installed on the towers, the lightning discharging currents through arresters and lightning energies absorbed by line arresters. The LWLs can be highly increased by installing line arresters on the transmission line towers in parallel with the insulator strings. It is not problem that the polymeric ZnO surge arresters are used in transmission lines to limit lightning overvoltages. (author). 9 refs., 11 figs., 1 tab.

  15. Deterioration and its improvement of magnetic blow out type surge arresters with series gaps; Jiki fukikeshigata gap tsuki hiraiki no keinen rekka to sono taio

    Energy Technology Data Exchange (ETDEWEB)

    Shirakawa, S.; Ito, M.; Terakado, S.; Iimura, N.; Mizukoshi, A. [Hitachi, Ltd., Tokyo (Japan)

    1995-12-20

    This paper describes deterioration characteristics of 266kV magnetic blow out type surge arrester with series gaps having actual about 30 years operation, and metal oxide surge arrester as its improvement. Main deteriorated components of surge arresters are extinguished chambers closed in series gaps, grading resistors for series gaps and covers for sealing. In case of deterioration of covers, water contents immerse into porcelain containers. Power frequency spark over voltage decreases gradually. Finally, surge arresters are possible to fail down at normal operating voltage. It is important to seal covers with gaskets between porcelain fittings and ceramics porcelains. 14 refs., 16 figs., 3 tabs.

  16. Effect of artificial aging on polymeric surge arresters and polymer insulators for electricity distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Carlos A.; Coser, E. [Laboratorio de Materiais Polimericos, Departamento de Engenharia de Materiais, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil)], e-mail: ferreira.carlos@ufrgs.br; Angelini, Joceli M.G. [Departamento de Materiais Eletricos, CPqD, Campinas, SP (Brazil); Rossi, Jose A.D. [Materiais Alta Tensao, CPqD, Campinas, SP (Brazil); Martinez, Manuel L.B. [Departamento de Engenharia Eletrica, UNIFEI, Itajuba, MG (Brazil)

    2011-07-01

    A study was conducted to evaluate new and laboratory-aged samples of surge arresters and anchorage polymeric insulators, for 12 and 24 kV networks, which are used by the Rio Grande Energia (RGE). Power utility polymeric compounds were analyzed by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TG), Dynamic-Mechanic Analysis (DMA), Fourier Transformed Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy (SEM) to verify changes in the insulator properties due to degradation occurred during the experiments. The analyses were carried out before and after 6 months of aging in laboratory devices (weather meter, 120 deg C, salt spray, immersion in water). After the aging experiments, high-voltage electrical tests were also conducted: a radio interference voltage test and, simultaneously, the total and the internal leakage currents were measured to verify the surface degradation of the polymeric material used in the housing. The impulse current test was applied with current values close to 5, 10 and 30 k A, in order to force an internal degradation. Results showed that only surface degradation is detected at the polymer. The main properties of the parts were not affected by the aging. It confirms that polymer insulator and surge arrester are appropriate for use in electricity distribution networks. (author)

  17. Protection against lightning surges provided by line arresters - Furnas' experience on 138 kV system

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Alessandra S.B.; Esmeraldo, Paulo C.V.; Nigri, Armando [FURNAS Centrais Eletricas S.A., Rio de Janeiro, RJ (Brazil)

    1999-07-01

    Furnas is about to make use of the line surge arrester technology in its network, based on studies that have been developed regarding with line performance improvement. In association to such studies, Furnas has installed six line arresters units on a 138 kV line with an arrester manufacturer cooperation, in order to get some experience on installation and maintenance, besides lightning incidence monitoring and line arrester behavior analysis. This paper presents first results and conclusions related to this 138 kV experimental installation on Furnas system. (author)

  18. Change of the Microstructure of ZnO Arrester Block by Lightning Surge Current and Ageing Test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Hee; Kang, Sung Man [Inha University (Korea)

    2000-07-01

    This paper deals with the change of the micro-structure of ZnO associated with lightning surge current and ageing test. In this work, a surge current generator which can produce 8/20 [{mu}s],6 [kA] impulse current is designed and fabricated to simulate the lightning impulse current. The residual voltage and leakage current flowing to ZnO blocks are observed. Also a compensation circuit was used in resistive current measurement. The micro-structures of ZnO arrester block were significantly changed by lightning surge current and accelerated temperature ageing test. (author). 6 refs., 7 figs., 1 tab.

  19. Metal oxide surge arrester research at the University of South Australia: An evaluation of polymer housed arresters and a new device for condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Baghurst, A.H. [Flinders Univ. of South Australia, Bedford Park, SA (Australia); Buratto, F. [Powercor Australia Ltd., Southbank, VIC (Australia); Krieg, T.W. [ETSA Transmission, Adelaide, SA (Australia)

    1995-12-31

    The use of polymer housed surge arresters within Australia has dramatically increased over the last 2-3 years. Unfortunately, the development of standards for testing polymer housed arresters has not kept pace with the development of these components. This paper describes on-going research at the Australian Electrical Testing Centre, University of South Australia, aimed at furthering knowledge about the performance of metal oxide surge arresters in the field. One project seeks to evaluate a range of polymer-housed arresters from different manufacturers with respect to seal integrity and accelerated ageing under a variety of environmental conditions. Test equipment being developed to perform the tests is described, and those parts of the new draft Australia standard relating to the performance of polymer-housed arresters critically reviewed. A second project involves the development of a new hand-held device for the measurement of that component of arrester leakage current which is in phase with the applied voltage. This parameter is widely accepted as a key indicator of the condition of a metal oxide arrester. The new device should be an order of magnitude cheaper than comparable commercial equipment currently available, and employs a micro controller to perform the required signal processing. (author). 1 tab., 2 figs., 11 refs.

  20. Effect of artificial aging on polymeric surge arresters and polymer insulators for electricity distribution networks

    Directory of Open Access Journals (Sweden)

    Carlos A. Ferreira

    2011-01-01

    Full Text Available A study was conducted to evaluate new and laboratory-aged samples of surge arresters and anchorage polymeric insulators, for 12 and 24 kV networks, which are used by the Rio Grande Energia (RGE. Power Utility Polymeric compounds were analyzed by Differential Scanning Calorimetry (DSC, Thermogravimetric Analysis (TG, Dynamic-Mechanic Analysis (DMA, Fourier Transformed Infrared Spectroscopy (FTIR and Scanning Electronic Microscopy (SEM to verify changes in the insulator properties due to degradation occurred during the experiments. The analyses were carried out before and after 6 months of aging in laboratory devices (weatherometer, 120 °C, salt spray, immersion in water. After the aging experiments, high-voltage electrical tests were also conducted: a radio interference voltage test and, simultaneously, the total and the internal leakage currents were measured to verify the surface degradation of the polymeric material used in the housing. The impulse current test was applied with current values close to 5, 10 and 30 kA, in order to force an internal degradation. Results showed that only surface degradation is detected at the polymer. The main properties of the parts were not affected by the aging. It confirms that polymer insulator and surge arrestor are appropriate for use in electricity distribution networks.

  1. Energy dependent model of a metal oxide surge arrester. Sanka aengata hiraiki no energy izon model

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, S.; Kan, M.; Masuzawa, K. (Toshiba Corp., Tokyo (Japan))

    1994-03-20

    This paper reports on modeling a zinc-oxide lightning arrester. The paper indicates that it is difficult to model the zinc-oxide elements by using non-linear resistance and inductance only, based on results of measuring hysteresis curves of restriction voltage on dual peak discharge of the elements. The paper then proposes a model (of numerical expression) that incorporates a concept that the restriction voltage decreases in response to energy absorbed by the elements from the discharge current. The paper explains a method for deciding on constants contained in the proposed expression, and a method to calculate the restriction voltage according to the proposed expression by using TACS of the program EMTP for circuit analysis. Further, it is indicated that the measured values of the restriction voltage on the dual-peak discharge current agree well with the calculated values from the proposed expression. A comparison was made on effects of this model and the conventional non-linear resistance model on the results of analyzing lightning surge responses in a 500-kV model system. 6 refs., 14 figs., 1 tab.

  2. Metal oxide surge arrester model with active V-I characteristics; Sanka aenkei hiraiki dotokusei model

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, T.; Funabashi, T.; Watanabe, H.; Takeuchi, N. [Meidensha Corporation, Tokyo (Japan); Ueda, T. [Chubu Electric Power Co. Inc., Nagoya (Japan)

    1996-11-20

    Generally a model of Metal Oxide Surge Arrester (MOSA) for numerical analysis uses a non-linear resistance. But actual Voltage-Current (V-I) characteristics of MOSA have hysteresis loop in time domain like i-{Phi} characteristic of a transformer and frequency dependency. The authors have investigated relation between the actual V-I hysteresis characteristics obtained by some current waveforms and static V-I characteristics. From the voltage difference between above two characteristics, an equation was derived and a new model of MOSA was developed. This model consists of a non-linear resistance representing fundamental V-I characteristic, a linear inductance and voltage source which depends on the absorbed energy. The calculated results by the proposed model are compared with measurement results by using the waveform of standard impulse current, steep front current and oscillated current. And the accuracy of the model has been confirmed to be satisfactory. The model is expected to be useful to investigate insulation coordination of power systems. 11 refs., 11 figs., 2 tabs.

  3. Application of High-Speed Infrared Imaging to Study Transient Joule Heating in Station Class Zinc Oxide Surge Arresters

    Energy Technology Data Exchange (ETDEWEB)

    Dinwiddie, R. B.; Wang, H.; Johnnerfelt, B.

    2004-03-15

    Zinc Oxide based surge arresters are widely used to safeguard and improve reliability of the electrical power delivering and transmission systems. The primary application of surge arresters is to protect valuable components such as transformers from lightning strikes and switching transients in the transmission lines. Metal-oxide-varistor blocks (MOV, e.g. ZnO) are used in surge arrester assemblies. ORNL has developed an advanced infrared imaging technique to monitor the joule heating during transient heating of small varistors. In a recent short-term R&D effort, researchers from ABB and ORNL have expanded the use of IR imaging to larger station-class arrester blocks. An on-site visit to the ABB facility demonstrated that the use of IR imaging is not only feasible but also has the potential to improve arrester quality and reliability. The ASEA Brown Bower (ABB) Power and Technology & Development Company located at Greensburg PA having benefited from collaborative R&D cooperation with ORNL. ABB has decided a follow-on CRADA project is very important. While the previous efforts to study surge arresters included broader studies of IR imaging and computer modeling, ABB has recognized the potential of IR imaging, decided to focus on this particular area. ABB plans to use this technique to systematically study the possible defects in the arrester fabrication process. ORNL will improve the real-time monitoring capability and provide analysis of the infrared images. More importantly, the IR images will help us understand transient heating in a ceramic material from the scientific standpoint. With the improved IR imaging ABB and ORNL will employ the IR system to visualize manufacturing defects that could not be detected otherwise. The proposed on-site tests at ABB Power Technology & Development processing facility will identify the defects and also allow quick adjustments to be made since the resulting products can be inspected immediately. ABB matched the DOE $50K funding

  4. A More Uniform Electric Field Distribution on Surge Arresters through the Optimal Design of Spacer and Fiber Glass Layer

    Directory of Open Access Journals (Sweden)

    M.R. Aghaebrahimi

    2013-04-01

    Full Text Available In this study, the optimal design of spacers and fiber glass layer of a metal oxide surge arrester is presented in order to achieve a more uniform electric field distribution, inside and outside the arrester. This is done by using intelligent algorithms and numerical analysis, i.e., Finite Element Method (FEM. The introduced method can be used in order to determine the optimal dimensions of spacers and fiber glass layer so that the electric field distribution is optimized and the lifetime of highly stressed ZnO blocks in the vicinity of HV electrode is increased. In order to verify the results, Differential Evolution (DE and Particle Swarm Optimization (PSO algorithms are used.

  5. The Effects of Local Police Surges on Crime and Arrests in New York City.

    Science.gov (United States)

    MacDonald, John; Fagan, Jeffrey; Geller, Amanda

    2016-01-01

    The New York Police Department (NYPD) under Operation Impact deployed extra police officers to high crime areas designated as impact zones. Officers were encouraged to conduct investigative stops in these areas. City officials credited the program as one of the leading causes of New York City's low crime rate. We tested the effects of Operation Impact on reported crimes and arrests from 2004 to 2012 using a difference-in-differences approach. We used Poisson regression models to compare differences in crime and arrest counts before and after census block groups were designated as impact zones compared to census block groups in the same NYPD precincts but outside impact zones. Impact zones were significantly associated with reductions in total reported crimes, assaults, burglaries, drug violations, misdemeanor crimes, felony property crimes, robberies, and felony violent crimes. Impact zones were significantly associated with increases in total reported arrests, arrests for burglary, arrests for weapons, arrests for misdemeanor crimes, and arrests for property felony crimes. Impact zones were also significantly associated with increases in investigative stops for suspected crimes, but only the increase in stops made based on probable cause indicators of criminal behaviors were associated with crime reductions. The largest increase in investigative stops in impact zones was based on indicators of suspicious behavior that had no measurable effect on crime. The findings suggest that saturating high crime blocks with police helped reduce crime in New York City, but that the bulk of the investigative stops did not play an important role in the crime reductions. The findings indicate that crime reduction can be achieved with more focused investigative stops.

  6. The Effects of Local Police Surges on Crime and Arrests in New York City

    Science.gov (United States)

    MacDonald, John; Fagan, Jeffrey; Geller, Amanda

    2016-01-01

    The New York Police Department (NYPD) under Operation Impact deployed extra police officers to high crime areas designated as impact zones. Officers were encouraged to conduct investigative stops in these areas. City officials credited the program as one of the leading causes of New York City’s low crime rate. We tested the effects of Operation Impact on reported crimes and arrests from 2004 to 2012 using a difference-in-differences approach. We used Poisson regression models to compare differences in crime and arrest counts before and after census block groups were designated as impact zones compared to census block groups in the same NYPD precincts but outside impact zones. Impact zones were significantly associated with reductions in total reported crimes, assaults, burglaries, drug violations, misdemeanor crimes, felony property crimes, robberies, and felony violent crimes. Impact zones were significantly associated with increases in total reported arrests, arrests for burglary, arrests for weapons, arrests for misdemeanor crimes, and arrests for property felony crimes. Impact zones were also significantly associated with increases in investigative stops for suspected crimes, but only the increase in stops made based on probable cause indicators of criminal behaviors were associated with crime reductions. The largest increase in investigative stops in impact zones was based on indicators of suspicious behavior that had no measurable effect on crime. The findings suggest that saturating high crime blocks with police helped reduce crime in New York City, but that the bulk of the investigative stops did not play an important role in the crime reductions. The findings indicate that crime reduction can be achieved with more focused investigative stops. PMID:27310252

  7. Metodología de Evaluación de los Pararrayos de Carburo de Silicio Assessment Methodology of Silicon Carbide Surge Arresters

    Directory of Open Access Journals (Sweden)

    Arnaldo G Kanashiro

    2010-01-01

    Full Text Available Este trabajo presenta los resultados de una investigación cuyo objetivo fue el diagnóstico de los pararrayos de carburo de silicio. En el laboratorio fueron realizados ensayos en pararrayos, siendo determinados los valores de tensión disruptiva en frecuencia industrial y de impulso atmosférico. Esos resultados fueron comparados con valores de la corriente de fuga, radiointerferencia y termovisión, obtenidos en mediciones en los mismos pararrayos. Se observó que valores más elevados de la corriente de fuga, en términos de amplitud y componente de tercer armónico, estaban asociados con una mayor degradación en esos pararrayos. Con base en esos resultados, se concluyó que la medición de la corriente de fuga puede proveer informaciones importantes sobre el estado de esos pararrayos. Mediciones del comportamiento de la corriente de fuga a lo largo de los años en las suestaciones pueden ayudar a identificar los pararrayos más degradados.This work presents results of a research project dveloped for determining the diagnostic of silicon carbide surge arresters. Tests were performed in these arresters in the laboratory, considering the power frequency spark-over voltage and lightning spark-over voltage tests. The results were compared with values of leakage current, radio-influence voltage test and thermovision, obtained in the same surge arresters. It was observed a reasonable correlation between high values of the leakage current, considering the amplitude and the third harmonic component, and the presence of degradation in the surge arresters. Therefore, it was concluded that leakage current measurements can provide important information about the stage of degradation of the surge arresters. Measurements in the substations during several years could provide the identification, in case of leakage current variations, of deteriorated silicon carbide surge arresters.

  8. Chemical characterization of polymeric surge arresters and insulators used in high voltage lines; Caracterizacao quimica de para-raios e isoladores utilizados em linhas de alta tensao

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, Joao B. de; Castro Junior, Joao B. de; Silva, Maria Elisa S.R. e; Freitas, Roberto F.S.; Sousa, Ricardo G. de [Lab. de Ciencia e Tecnologia de Polimeros, Dept. de Engenharia Quimica da EE.UFMG, Belo Horizonte, MG (Brazil); Souza, Breno P.G. de [CEMIG Distribuicao S/A, Belo Horizonte, MG (Brazil)], e-mail: bpgsouza@gmail.com

    2011-07-01

    In the last two decades, traditional porcelain and glass surge arresters and insulators, used in the electrical system, have been replaced by polymeric materials. For this type of application it is recommended that these devices have a high resistance to environmental stresses and impacts without suffering degradation process. Considering the environmental conditions these polymers are exposed to, when used for this purpose, studies of their chemical composition are needed. In this work, polymeric materials present in surge arresters and insulators used in electrical system were chemically characterized by Fourier Transform Infrared Spectroscopy (FTIR). FTIR analysis showed that the samples tested are made of poly(dimethylsiloxane) - PDMS (silicone) and additives such as alumina trihydrated [Al (OH)3] and calcium carbonate. (author)

  9. Microstructural evaluation of a varistor block utilized in high voltage surge arresters; Avaliacao microestrutural de um bloco varistor utilizado em para-raios de alta tensao

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, J.M. de; Dias, R.; Furtado, J.G. de M., E-mail: jma_ime@yahoo.com.b [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Assuncao, F.C.R. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2010-07-01

    Varistor is a semiconductor ceramic device characterized to have a high non-linear electrical resistance, it is used as active element of surge arresters with purpose of protecting of electro-electronics systems. Its properties are directly dependents of chemical composition and microstructural characteristics, such as grain size, porosity, twins and phases distribution. This work has the objective to characterize microstructurally a commercial varistor block of ZnO used in high voltage surge arrest and from this characterization to infer aspects about of its electrical macroscopic performance. DRX and SEM-EDS were used for microstructural analysis. The microstructural evaluation allows pointing the critical points of microstructure and, suggest relevant aspects to the improvement of commercial varistor microstructure, optimizing the electrothermal behavior of the device. (author)

  10. Online-monitoring of MO-surge arresters with passive surface acoustic wave radio sensors; Online-Temperaturmessung an MO-Ueberspannungsableitern mit funkabfragbaren Oberflaechenwellensensoren

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichsen, V. [Siemens AG, Berlin (Germany). Bereich Energieuebertragung und -verteilung; Scholl, G. [Siemens AG, Muenchen (Germany). Fachzentrum Oberflaechenwellentechnik und Funksensorik

    1998-08-24

    Today no practicable and economical solutions are available for an overall online-monitoring of high-voltage metal oxide surge arresters, which should comprise a surge counter function, an energy monitor and the monitoring of electrical aging if required. A permanent measurement of the arrester temperature on high potential, which basically could provide all these functions, has not yet been realized due to the related technical problems. However, newly developed high-frequency temperature measuring systems based on wireless passive surface acoustic wave temperature sensors are now offering this possibility for the first time. They are actually being field-tested in a 420-kV-arrester and have shown a good performance so far. (orig.) [Deutsch] Zu einem geschlossenen Online-Monitoringkonzept von Hochspannungs-Metalloxid-Ableitern, das eine Ansprechzaehlerfunktion, einen Energiemonitor and gegebenenfalls eine Ueberwachung elektrischer Kennlinienalterung enthalten sollte, fehlen bis heute geeignete, wirtschaftlich vertretbare Loesungen. Eine dauernde Messung der Ableitertemperatur auf Hochspannungspotential, mit der an sich alle genannten Funktionen einfach realisiert werden koennten, scheiterte bisher an der technischen Umsetzbarkeit. Neuentwickelte funkabfragbare Oberflaechenwellen-Temperatursensoren eroeffenen nun erstmalig diese Moeglichkeit. Eingebaut in einem 420-kV-Ableiter, befinden sie sich zur Zeit in einem Feldversuch in praktischer Erprobung und erfuellen dort alle in sie gesetzten Erwartungen. (orig.)

  11. VFTO仿真计算中避雷器模型研究%Study on Surge Arrester Model in the Simulation and Calculation of VFTO

    Institute of Scientific and Technical Information of China (English)

    钟笑拳; 周力行; 赵宪; 邓慧都; 刘涛; 彭杰

    2014-01-01

    With the wide use of the all closed gas insulate substation (GIS), the very fast transient overvoltage ( VFTO) caused by the operations of disconnectors has triggered more and more accidents. The metal oxide arrest-er has been widely applied in terms of limiting over voltage. This paper summarizes the current application of the four types of surge arrester model, and builds the corresponding electromagnetic transient program ATP-EMTP sim-ulation models using. Taking a 1000kV GIS in China as a research backgroudne, the very fast transient overvoltage caused by the operations of disconnectors by the action of the four surge arrester model is simulated, acquire the o-ver voltage waveform in the time domain is acquired, amplitude-freequency charateristic diagram is then transfor-ming the time domain waveform using MATLAB. The inhibitory effects of the four types of surge arrester model on VFTO are compared. The results show that the fourth model is more accurate, it can better suppress the amplitude and frequency of the overvoltage.%随着全封闭式气体绝缘变电站( GIS)的广泛引用,由隔离开关操作引起的特快速暂态过电压( VFTO)造成的事故频发。金属氧化物避雷器在限制过电压方面应用广泛,总结了目前应用的4种避雷器模型,运用电磁暂态程序ATP-EMTP分别建立仿真模型,以国内某1000 kVGIS电站为研究背景,分别模拟了在这4种避雷器模型作用下由隔离开关分闸操作引起特快速暂态过电压,得到了过电压的时域波形图,再运用MATLAB对时域波形进行变换得到VFTO的幅频特性图。对比了4种避雷器模型对VFTO的抑制效果,其中第4种模型更加精确,对过电压幅值、频率抑制效果最好。

  12. Fault analysis and processing of moistened metal oxide surge arresters%一起金属氧化物避雷器故障分析与处理

    Institute of Scientific and Technical Information of China (English)

    晏桂林; 龚宁; 张志权; 杨兴华

    2013-01-01

    The working principle of metal oxide surge arresters was described, and some of its fault detection methods were outlined. For a power plant with a 220 kV metal oxide arrester defect due to abnormal discharge current, the preliminary determination of fault nature was taken followed by promptly quitting running by the diagnostic method of resistive current testing, infrared imaging detection combined with outages routine testing. According to the dismantling of the returned defective arrester, the defect caused by lightning arrester moisture was found out, and the moistened cause of the arrester was further analyzed with the structural component.%简述了金属氧化物避雷器的工作原理,并概述了其故障检测的一些方法。针对某电厂一起220 kV金属氧化物避雷器泄流电流异常的缺陷,采用对避雷器进行带电阻性电流测试、红外线成像检测及停电常规试验相结合的诊断方法,初步判定了故障性质和故障部位。通过对退运缺陷避雷器的拆解,发现缺陷是因避雷器受潮引起,并从故障构件结构入手分析了发生受潮的原因。

  13. Over-voltage surge arrester for lightning protection; Einsatz von Ueberspannungsableitern beim Blitzschutz. Notwendige Strombelastbarkeit von Varistoren in induktiv gekoppelten Schleifen

    Energy Technology Data Exchange (ETDEWEB)

    Haeberlin, H. [Berner Fachhochschule, Hochschule fuer Technik und Architektur (HTA), Burgdorf, (Switzerland)

    2001-07-01

    The article discusses the necessary loading characteristics of varistors that are used in inductively coupled loops to provide protection against over-voltages produced by lightning strikes. An overview of various types of commercially available surge arresters is presented; their function and their use in photovoltaic installations is discussed in detail. The calculation of the inductively induced currents is discussed in depth for loops with and without varistors. Diagrams with graphs of current against time and mathematical solutions for the representation of the induced currents are presented in detail. The article is supplemented by examples of the calculation of varistor current and a simplified procedure is presented for the definition of the varistor currents necessary for a particular application.

  14. Rocket-triggered lightning experiment and application study of transmission line for metal oxide surge arresters; Sanka aengata hiraiki no roketto yurai jikken kekka to sodensen eno tekiyo kento

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, H. [Meidensha Electric Mfg. Co. Ltd., Tokyo (Japan); Nakamura, K. [Nagoya Inst. of Technology, Nagoya (Japan); Kobayashi, M.

    1997-03-20

    In the measurement of the rocket-triggered lightning current and voltage, executed from 1986 to 1995 at mountain top of Okushishiku in Kanazawa areas, the authors succeeded in artificially inducing the winter lightning to the arresters. Using the data obtained in those measurements, we analyzed the energy absorption characteristics of surge arresters, which are installed on every tower of transmission line for three phases, by EMTP. The energy withstand capability of individual arrester was verified as approximately same as expected value. Analysis result for energy share of each arrester connected in parallel showed that usual light duty arresters installed on every tower have possibility to be able to absorb the big winter lightning energy even if the lightning hit directly the power line. 14 refs., 6 figs., 3 tabs.

  15. Analysis on Lightning Protection Performance of Metal Oxide Surge Arresters for Transmission Lines%复合绝缘外套线路型ZnO避雷器防雷运行分析

    Institute of Scientific and Technical Information of China (English)

    李谦; 钟定珠; 彭向阳; 樊灵孟; 罗真海; 林火华

    2001-01-01

    According to analysis of the lightning protection practice of Metal Oxide Surge Arresters on the Guangdong 110 kV and 220 kV Transmission Lines in recent years, the positive effectiveness of Metal Oxide Surge Arresters on lowering the lightning stroke tripp efficiency has been preliminarily affirmed. The existing issues in the site-selection, installation and maintenance are discussed, the beneficial suggestions for popularizationis also presented.%总结了复合绝缘外套线路型ZnO避雷器近年在广东省110、220 kV输电线路的运行经验;肯定了线路避雷器降低线路雷击跳闸率的积极效果;讨论了在解决选点、安装和运行维护等方面存在的问题并提出了建议。

  16. Development of an electro-thermal model for ZnO surge arrester under contamination; Desarrollo de un modelo electro-termico para apartarrayos de ZnO bajo contaminacion

    Energy Technology Data Exchange (ETDEWEB)

    Guardado Zavala, J.L.; Moreno Barraza, M.; Zazueta Pena, H.; Venegas Rebollar, V.; Melgoza Vazquez, E. [Instituto Tecnologico de Morelia, Morelia, Michoacan (Mexico)]. E-mail: lguarda@prodigy.net.mx; hzazuetapea@yahoo.com; vvenegas@yahoo.com; emelgoza@iimorelia.edu.mx

    2010-01-15

    An electro-thermal model for a Zinc Oxide (ZnO) surge arrester under contamination test is presented. The model is based in three sub-models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacitance and a non-linear resistor. The thermal model takes into account the heat generated and dissipated by the column of varistors and its surroundings. The contamination is represented by dynamic impedance obtained from measurements in the arrester column during contamination tests. The full model is validated by calculating the temperature increase during contamination tests carried out in a two units ZnO surge arrester, class 190 kV. Finally, the results of the effect of several design and construction parameters in the voltage and temperature distribution in the arrester column during contamination tests are presented. [Spanish] Se presenta el modelo electro-termico para un apartarrayos de Oxido de Zinc (ZnO) durante pruebas de contaminacion. El modelo esta compuesto de tres sub-modelos: electrico, termico y de contaminacion, los cuales interactuan armonicamente para obtener el comportamiento del apartarrayos durante pruebas de contaminacion. El modelo electrico se obtiene de mediciones y esta compuesto de una capacitancia y una resistencia no-lineal. El modelo termico considera el calor generado y disipado en la columna de varistores y su entorno. La contaminacion se representa como una impedancia dinamica, cuyos valores se obtienen de mediciones en la columna del apartarrayos durante pruebas de contaminacion. El modelo se valida determinando el incremento de temperatura durante pruebas de contaminacion en un apartarrayos de ZnO de dos unidades clase 1990 kV. Finalmente, se presentan los resultados del impacto de diversos parametros de diseno y construccion en la distribucion de voltaje y temperatura en el apartarrayos

  17. 可控金属氧化物避雷器操作冲击动作特性试验方法%Test Method for Switching Impulse Response Properties of Controllable Metal Oxide Surge Arrester

    Institute of Scientific and Technical Information of China (English)

    贺子鸣; 陈维江; 陈秀娟; 颜湘莲

    2012-01-01

    The controllable metal oxide surge arrester is a new electrical set-up which can deeply reduce switching overvoltage in UHV transmission system.The conventional arrester test method could not be used to validate the switching impulse response properties of the controllable metal oxide surge arrester.Consequently,we discussed the switching impulse response properties of the controllable metal oxide surge arrester,and put forward a new test method which switching impulse current test and switching impulse voltage test were carried out respectively fitting test requirements.Moreover,we verified the response delay of controllable switch and the residual voltage of controllable metal oxide surge arrester in the test.The parallel modulated wave capacitor was used in the existing residual voltage test circuit to implement the switching impulse current test method,the impulse voltage generator,regulator and measurement circuit were used to implement the switching impulse voltage test method,and a designed 110 kV controllable metal oxide surge arrester was used in the verification test.In the test,the controllable arrester could respond reliably under switching impulse voltage.By comparing with the conventional arrester,the decreased range of the residual voltage of controllable arrester was close to the designed controllable rate of 25% in the same current.Furthermore,the designed controllable arrester with expected limit effect was verified,and the availability of the approach was verified.%可控金属氧化物避雷器(简称可控避雷器)是一种可以深度降低特高压交流输电系统操作过电压的新型设备,现有的避雷器试验方法无法检验其在操作冲击下的动作特性。为此,分析了可控避雷器在操作冲击下的动作特性,设计了检验可控开关动作时延和可控开关动作前后避雷器残压这两个动作特性的试验方法,采用操作冲击电流和操作冲击电压分别进行了试验

  18. Development of a Technique for Representing Lightning Arresters in the Surge Simulations based on the FDTD Method and its Application to the Calculation of Lightning-Induced Voltages on a Distribution Line

    Science.gov (United States)

    Tatematsu, Akiyoshi; Noda, Taku

    Recently, the FDTD (Finite Difference Time Domain) method, which directly solves Maxwell's equations, has been applied to lightning surge problems involving electrical wires in three-dimensional arrangements, such as power and telecommunication circuits. Lightning arresters are installed to protect the circuits from abnormal voltages due to lightning, for example. We have already proposed a technique for representing a lightning arrester in the FDTD method. However, this technique simply represents the V-I characteristics of the arrester using just three parameters and requires a method for avoiding the numerical oscillation due to the nonlinear characteristics of the arrester. In this paper, we propose a new technique for representing the V-I characteristics of the arrester in detail using the piecewise linear function defined by several points and for improving the numerical stability without the method for avoiding the numerical oscillation. Using a test circuit, the proposed technique is validated by comparing the results calculated by the FDTD method with those by the EMTP (ElectroMagnetic Transients Program) which is a circuit-theory-based simulation program. Finally, as an example of applying the proposed technique, we calculate lightning-induced voltages on a distribution line with a lightning arrester. The calculated results by the FDTD method agree well with those by a conventional method based on circuit theroy.

  19. Application of Zinc Oxide Surge Arresters Live Test in Condition-based Maintenance Work%氧化锌避雷器带电检测在状态检修工作中的应用

    Institute of Scientific and Technical Information of China (English)

    闫尚斌; 唐领英

    2013-01-01

      随着电力系统的不断发展,对供电可靠性的要求越来越高,设备的试验由传统的定期试验转入状态检修试验。氧化锌避雷器在电网中有着重要的作用,它的带电测试,方法简单,数据准确,在状态检修中,发挥着重要的作用。本文主要介绍了氧化锌避雷器的带电测试原理,结合阳泉供电分公司实际应用,论证综合分析判断金属氧化锌避雷器带电测试数据。%With the continuous development of the electric power system, it has higher demand on the power supply reliability, so the test of the equipment is transferring from the traditional periodic tests to condition-based maintenance test. Zinc oxide surge arresters play an important role in the power grid. Because its live test method is simple and its data is accurate, it plays an important role in condition-based maintenance. This paper describes the principle of live test of zinc oxide surge arresters, combined with the practical application in Yangquan Electric Power Supply Branch, demonstrated and analyzed the live test data of the metal zinc oxide surge arresters.

  20. Study of accelerated aging of polymeric surge arresters and insulators used in high voltage lines; Estudo sobre o envelhecimento acelerado de para-raios e isoladores polimericos usados em linhas de alta tensao

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, Joao B. de; Castro Junior, Joao B. de; Silva, Maria Elisa S.R. e; Freitas, Roberto F.S.; Sousa, Ricardo G. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Quimica. Lab. Ciencia e Tecnologia de Polimeros; Souza, Breno P.G. de [CEMIG Distribuicao S.A., Belo Horizonte, MG (Brazil)], e-mail: sousarg@ufmg.br

    2011-07-01

    The use of polymeric materials in the electrical system has dramatically increased in recent years, in quantity as well as in quality. However, the use of these materials has been very empirical, being necessary a more directed and well based study towards their application in energy sector, especially concerning their early deterioration. In this study, the behavior of some surge arresters and insulators, used in power lines, after suffering aging artificial weathering chamber, was investigated. The absorption spectra in the infrared (FTIR) was used as analytical technique for study of aging. Of the five samples tested, only one showed an oxidation process after 1500 hours of artificial weathering. (author)

  1. 屏蔽法测量金属氧化物避雷器的泄漏电流%Research on Leakage Current Measurement for Metal Oxide Surge Arrester with Shielding Method

    Institute of Scientific and Technical Information of China (English)

    秦锟

    2015-01-01

    Leakage current is an important parameter of characterization of its performance, as the growth of the running time , ex-perimental value will be critical in specification, so that it can not make an accurate judgment. This paper based on the 500 kV pre-ventive test of metal oxide surge arrester as an example, analyzes the influencing factors of leakage current in arrester test and the reason for great error in the conventional test method, proposed in the test with the shielding wire method that is commonly known as shielding arrest test experiment, in order to reduce the measurement error and the workload.%泄漏电流是表征其性能的重要参数,随着运行时间的增长,试验值临界于规程值,不能作出准确的判断。以500 kV金属氧化物避雷器的预防性试验为例,分析了避雷器试验中影响泄漏电流的因素及常规试验方法测量误差大的原因,提出了在试验时用屏蔽线进行避雷器试验的俗称屏蔽法的试验方法,以减小测量误差及工作量。

  2. Electrothermal and microstructural characterization of varistors ceramics used in high-voltage surge arresters; Caracterizacao eletrotermica e microestrutural de ceramicas varistoras utilizadas em para-raios de altas tensoes

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Flavio Bittencourt; Furtado, Jose G. de Melo [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Nobrega, Maria C. de S. [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia

    2008-07-01

    In this work is studied the electrothermal behavior of varistor ceramic blocks used in high voltage surge arresters of transmission and distribution lines, relating this behavior to microstructural characteristics of the studied varistor ceramics. We studied blocks of zinc oxide varistors with nominal voltage of 4.0 kV, by and voltage-capacitance characterization curves, reference voltage test, impulse residual voltage, polarization tests and induced degradation tests. On the other hand, the microstructural characterization was made by scanning electron microscopy and energy-dispersive spectroscopy. The obtained results allow to correlate the behavior of the resistive component of the leakage current with the microstructural characteristics of the studied varistors, specially in pre-breakdown region. (author)

  3. 有关线路避雷器标准和参数设计中的几个问题%Discussion and Suggestion on Standard and Design of Surge Arresters for Power Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    高玉明; 吴维韩; 欧阳昌宜

    2001-01-01

    In this paper a discussion on the new formulated standard of “Metal oxide surge arresters for a. c. power transmission lines”Draft has been made. Some viewpoints and suggestions on design of this new arrester are also introduced. Such as basic design requirements rated voltage d. c. reference voltage long duration current impulse switching current impulse discharge voltage characteristics of series gap withstand voltage of support insulator of series gap etc.%结合新制订的电力行业标准“交流输电线路用复合外套金属氧化物避雷器”讨论稿,对一些参数设计问题,如线路避雷器设计的基本要求、额定电压、直流1 mA参考电压、方波冲击电流值、操作冲击通流能力、串联间隙的放电电压特性、串联间隙支撑绝缘子试验电压值的确定等,提出一些看法与建议,供有关部门特别是制订标准的部门参考和讨论,以期有利于该类新产品的推广使用和设计水平的提高。

  4. Lightning Surge Analysis in 154 kV S/S due to Flashover on the 4 Circuits Tower

    Energy Technology Data Exchange (ETDEWEB)

    Woo, J. W.; Shim, E. B.; Kwak, J. S.; Choi, B. J. [Korea Electric Power Corporation (Korea)

    2000-07-01

    This paper describes the analysis results for the protection of lightning surge at 154 kV substation. We found that the surge arrester is needed at the inlet structure. The maximum overvoltage is about 1,500 kV at the circuit breaker without the surge arrester at the inlet structure. This value can be lower than 600 kV by installing the surge arrester at the inlet structure. In addition to the shield wire should be considered to prevent the shielding failure by the direct lightning stroke. (author). 6 refs., 8 figs.

  5. Cardiac arrest

    Science.gov (United States)

    ... Article.jsp. Accessed June 16, 2014. Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening ... PA: Elsevier Saunders; 2011:chap 63. Myerburg RJ, Castellanos A. Cardiac arrest and audden aardiac death. In: ...

  6. Switching Surge Analysis of Vacuum Circuit Breaker using EMTP

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ik Mo; Kim, Ji Hong [Hyundai Heavy Industry, Mechatronics Research Institute (Korea)

    2000-07-01

    The first objective of this study is to set up the switching surge analysis method in motor driving distribution system. The simplified model which can simulate the motor energization and circuit breaker re-ignitions, and each circuit element model is presented in this paper. The second objective is to calculate the quantity of surge over-voltage in real nuclear power station. And the surge suppressing measures are verified on the simulation basis. It is clarified that most cases are not satisfactory to meet the IEEE standard 522-1992 without using surge suppressing measures. In cases that the surge arrester are installed in distribution board at the load side of circuit breaker. The IEEE specification is fully met. (author). 6 refs., 4 figs., 3 tabs.

  7. Analysis of the Metal Oxide Surge Arresters DC High Voltage Test%关于金属氧化物避雷器直流高压试验分析

    Institute of Scientific and Technical Information of China (English)

    孟丽英; 孟瑞平; 杨志帮

    2015-01-01

    在电网运行过程中,正确使用避雷器可以有效降低事故发生的概率。金属氧化物避雷器是目前使用最广的避雷器,它具有结构稳定、材料简单、效果显著的优势,而且在保护电力系统不受天气因素干扰方面,其优势尤为突出。因此,在当前的电网运行过程中,金属氧化物避雷器是不可或缺的一部分。%During the operation of the grid, the proper use of arrester can reduce the probability of accidents. MOA is currently the most widely used arrester, which has structural stability, simple materials, the effect is a significant advantage, but also in power system protection from the weather disturbance is concerned, the advantage is particularly prominent. Therefore, in the current process of operation of the grid, the MOA is an integral part.

  8. Defects Analysis of a Main Transformer 11OkV Side C Phase Metal Oxide Surge Arrester%某主变110kV侧C相金属氧化物避雷器缺陷分析

    Institute of Scientific and Technical Information of China (English)

    卢斌; 毛学峰; 张国旗; 余后霞

    2013-01-01

    针对某主变110kV侧C相金属氧化物避雷器(Metal Oxide Arrester,MOA)存在1mA运行区直流参考电压偏低及泄漏电流超标的现象.金属氧化物避雷器阀片受潮或者老化时,其绝缘电阻值会大幅减小,以此检测阻性电流可以有效地监测避雷器绝缘状况.通过进行解体检查和直流试验及绝缘电阻分析,判断MOA缺陷的主要原因是:内部阀片的老化导致绝缘下降,泄漏电流增加.

  9. Investigating Different ZnO Arresters Models against Transient Waves

    Directory of Open Access Journals (Sweden)

    A. Babaee

    2011-12-01

    Full Text Available Metal oxide surge arresters have dynamic characteristics that are significant for over voltage coordination studies involving fast front surges. Several models with acceptable accuracy have been proposed to simulate this frequency-dependent behavior. In this paper, various electrical models are presented for surge arrester performance simulation against lightning impulse. The desirable model is obtained by using simulation results of the existing models and experimental tests. The IEEE proposed model is a proportional model can give satisfactory results for discharge currents within a range of time to crest for 0.5 to 45 :s but due to no existing residual voltage resulting switching current on the manufacture's datasheets decrease its performance generally. In this study the maximum residual voltage due to current impulse is analyzed too. In additional, the amount of discharged energy by surge arrester is focused.

  10. Daily Arrests

    Data.gov (United States)

    Montgomery County of Maryland — This dataset provides the public with arrest information from the Montgomery County Central Processing Unit (CPU) systems. The data presented is derived from every...

  11. 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.

  12. 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.

  13. 基于GPS同步的金属氧化锌避雷器无线带电检测系统设计和实现%Design and Implement of Wireless Metal Oxide Surge Arrester Detect System Based on GPS Synchronous

    Institute of Scientific and Technical Information of China (English)

    徐剑; 宋辉; 盛戈皞; 江秀臣

    2013-01-01

    金属氧化锌避雷器(MOA)的阻性电流大小能较好地反应其设备状态,传统的MOA阻性电流测量方法每次测试时需在电压互感器二次侧接线,有较大的安全隐患.提出了一种新型的MOA阻性电流无线测量方法,基于GPS和无线通信模块实现便携式电流检测装置与电压监测装置的无线同步测量,通过基于傅里叶级数的算法实现检测MOA的阻性电流.重点阐述了系统的组成以及硬件的设计原理和实现方法,试验测试和现场运行测试结果表明方法满足MOA阻性电流测量的要求.%The resistive current of Metal oxide surge arrester ( MOA) indicates the condition of the equipment well. The traditional method of the measurement of MOA resistive current need wiring in the output of PT second side every time. This brings more security risks. This paper proposed a new method of MOA resistive current wireless measurement. It uses a portable current detection device and voltage monitoring device to realize wireless simultaneous measurement based on GPS and wireless communication, and detects the resistive current of MOA based on Fourier Series algorithm. This thesis focus on the system composition and hardware design. The result show that the method meets the requirement of measurement of resistive current of MOA.

  14. Surge-damping vacuum valve

    Science.gov (United States)

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  15. Svalbard surging glacier landsystems

    Science.gov (United States)

    Lovell, Harold; Benn, Douglas; Lukas, Sven; Flink, Anne

    2014-05-01

    The percentage of Svalbard glaciers thought to be of surge-type is somewhere between 13-90% according to different sources variously based on statistical analysis and observations of diagnostic glaciological and geomorphological features, e.g. looped moraines. Developing a better understanding of which of these figures, if either, is most realistic is important in the context of glacier dynamics and related contributions of small glaciers and ice caps to sea level change in the immediate future. We present detailed geomorphological assessments of the margins of several known surge-type glaciers in Svalbard in order to update and improve the existing framework by which they are identified, and to provide a foundation for future reassessments of the surge-type glacier population based on distinct landform-sediment assemblages. Three landsystems are proposed: (1) Surges of small valley glaciers produce a prominent ice-cored latero-frontal moraine at their surge maximum and are characterised by an inner zone of ice stagnation terrain (hummocky topography, kettle lakes, debris flows) with no or only very few poorly-defined bedforms (crevasse squeeze ridges, eskers and flutes) and no recessional moraines. Many of these glaciers may have surged in the past but show no signs that they have the capability to do so again in the future. (2) Larger land-terminating glaciers, often with several tributaries, typically produce a push moraine complex which contains evidence for multiple advances, as identified from ridge-meltwater channel relationships. The inner zone often contains a large lagoon, partly dammed by the push moraine complex, and widespread ice stagnation terrain. Crevasse squeeze ridges, eskers and flutes are well-defined but small and limited in number and distribution. (3) Surges of large tidewater glaciers produce distinctive, often multi-generational, landform assemblages both in submarine and lateral terrestrial positions. The well-preserved submarine record

  16. 高速铁路牵引供电接触网用带间隙避雷器的研制%Development of Metal Oxide Surge Arrester With Series Gap for Traction Power Supply System Catenary of High-speed Electrified Railway

    Institute of Scientific and Technical Information of China (English)

    边凯; 陈维江; 沈海滨; 李成榕; 王立天; 赵海军; 王彦利; 尹彬; 李庆余

    2013-01-01

    中国高速铁路线路高架桥路段比例大,且相对集中在雷电活动较强烈地区,牵引供电接触网雷击故障多,须采取措施加以解决.在接触网绝缘子旁并联安装带间隙避雷器是一种有效的防雷措施.根据接触网布局结构和运行可靠性要求高的特点,提出了一种与绝缘子一体化安装的避雷器分体结构型式,特别设计抱箍增强安装稳定性,提出了一种避雷器本体压力释了U型放结构可有效释放短路能量,研究选择了本体关键参数和串联间隙距离,确定了短路试验和振动试验方法和条件,对样品进行了雷电冲击放电伏秒特性试验、短路试验和振动试验,从而验证该技术性能的可靠性.最后,研制了适合接触网正馈线、接触线和加强线绝缘子使用的3种形式避雷器,并获国家发明专利授权,已在京沪高速铁路上试运行,状态良好.%In China, viaduct sections are widely adopted in high-speed electrified railway lines and most of the lines go through strong lightning activity areas. This leads to high lightning stroke failure rate of traction power supply catenary. To install metal oxide surge arrester with series gap(GMOA) parallel with insulators is an ideal lightning protection measure to solve the problem. In the paper, a kind of arrester and insulator integral mounting structure type was put forward, U-shaped clamp was specially designed to enhance the stability of the installation, an arrester body pressure release structure was presented to release the short-circuit energy effectively, the primary parameters of MOA body and the distance of series gap were selected, the test methods and conditions of short-circuit test and vibration test were provided, and the samples proved reliable by the results of lightning impulse test .short-circuit current test and vibration test. Three kinds of GMOA products with positive feeder/contact wire/strengthened contact wire insulators were

  17. 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.

  18. High Energy Surge Arrester Technology Development. Part 2.

    Science.gov (United States)

    1986-02-28

    8217gig& becquerel (GBq) K degree (angle) 1.745 329 X E -2 radian (rad) degree Fahrenheit is - (t= f + 459.67)/1. 8 degree kelvin (10 electron volt 1. 602...X E 41 kilogram (11) torr (mm Hg. 0 C) 1.333 22 X E -1 klo pascal (kPs) *The becquerel (9q) is the SI unit of radioactivity; I fq - 1 event/s. -The...4 ir X , HENRIES /METER p i = FUNCTION OF FREQUENCY N = NUMBER OF TURNS V = OPERATING VOLTAGE, (/VOLTS) A f = OPERATING FREQUENCY, (HERTZ) I

  19. Heterogeneity in Karakoram glacier surges

    Science.gov (United States)

    Quincey, Duncan J.; Glasser, Neil F.; Cook, Simon J.; Luckman, Adrian

    2015-07-01

    Many Karakoram glaciers periodically undergo surges during which large volumes of ice and debris are rapidly transported downglacier, usually at a rate of 1-2 orders of magnitude greater than during quiescence. Here we identify eight recent surges in the region and map their surface velocities using cross-correlation feature tracking on optical satellite imagery. In total, we present 44 surface velocity data sets, which show that Karakoram surges are generally short-lived, lasting between 3 and 5 years in most cases, and have rapid buildup and relaxation phases, often lasting less than a year. Peak velocities of up to 2 km a-1 are reached during summer months, and the surges tend to diminish during winter months. Otherwise, they do not follow a clearly identifiable pattern. In two of the surges, the peak velocity travels down-ice through time as a wave, which we interpret as a surge front. Three other surges are characterized by high velocities that occur simultaneously across the entire glacier surface, and acceleration and deceleration are close to monotonic. There is also no consistent seasonal control on surge initiation or termination. We suggest that the differing styles of surge can be partly accounted for by individual glacier configurations and that while some characteristics of Karakoram surges are akin to thermally controlled surges elsewhere (e.g., Svalbard), the dominant surge mechanism remains unclear. We thus propose that these surges represent a spectrum of flow instabilities and the processes controlling their evolution may vary on a glacier by glacier basis.

  20. Aging assessment of surge protective devices in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.F.; Subudhi, M. [Brookhaven National Lab., Upton, NY (United States); Carroll, D.P. [Florida Univ., Gainesville, FL (United States)

    1996-01-01

    An assessment was performed to determine the effects of aging on the performance and availability of surge protective devices (SPDs), used in electrical power and control systems in nuclear power plants. Although SPDs have not been classified as safety-related, they are risk-important because they can minimize the initiating event frequencies associated with loss of offsite power and reactor trips. Conversely, their failure due to age might cause some of those initiating events, e.g., through short circuit failure modes, or by allowing deterioration of the safety-related component(s) they are protecting from overvoltages, perhaps preventing a reactor trip, from an open circuit failure mode. From the data evaluated during 1980--1994, it was found that failures of surge arresters and suppressers by short circuits were neither a significant risk nor safety concern, and there were no failures of surge suppressers preventing a reactor trip. Simulations, using the ElectroMagnetic Transients Program (EMTP) were performed to determine the adequacy of high voltage surge arresters.

  1. 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.

  2. A METHOD OF DETERMINING THE ABILITY OF THE ARRESTER TO ABSORB ENERGY WITHOUT BREAKING THE HEAT BALANCE

    Directory of Open Access Journals (Sweden)

    S.Yu. Shevchenko

    2015-08-01

    Full Text Available Purpose.The aim of this study is to obtain a method for determining the capacity surge arrester nonlinear absorb energy without breaking the heat balance in modes of long-term application of operating voltage, which allows for analysis of their work in terms of violations as electricity. Methodology. For values of the energy passing through the arrester must be able to determine the current value for the voltage value in the area of leakage current-voltage characteristics. We have carried out calculations of the energy passing everywhere arrester for certain periods of time based on the current-voltage characteristics obtained experimentally. Analysis of the experimental current-voltage characteristics of resistors and literature led to the important conclusion that the dielectric properties of the ceramic varistor affect the value of active power losses in the arrester only when the active component of the leakage current is very small. This is confirmed by the characteristics of different classes of varistor voltage. This property of varistors and surge arresters shows the need to consider how the dielectric and conductive properties of the varistor ceramics in the analysis of work in the area of the arrester leakage current-voltage characteristic. These results demonstrate the need to clarify the mathematical model and the method for determining the energy dissipates in the area of the arrester leakage current CVC with their account. Results. The study, an improved mathematical model for calculating energy affects surge arrester during its working life. The study obtained the method, of evaluation capacity surge arrester, maintains heat balance throughout working life. Based on experimentally obtained current-voltage characteristic of the varistors is defined voltage at which surge arrester starts conducting active current. This allowed to receive specified mathematical model for calculating energy affects surge arrester and develop a method

  3. Pollution performance of 110 kV metal oxide arresters

    Energy Technology Data Exchange (ETDEWEB)

    Chrzan, K.; Pohl, Z. [Technical Univ. of Wroclaw (Poland). Dept. of Electrical Engineering; Grzybowski, S. [Mississippi State Univ., MS (United States). Dept. of Electrical and Computer Engineering; Koehler, W. [Univ. of Stuttgart (Germany). Dept. of Electrical Engineering

    1997-04-01

    Pollution test results of single unit 110 kV metal oxide surge arresters with porcelain housing according to the solid layer and salt fog methods are presented. During 6 hours of testing, the internal and external charge and maximum temperature along the varistor column were measured. The formation of single stable dry bands on the housing was often observed, especially during salt fog tests. In such cases, the varistor temperature can reach about 70 C. The simple electrical model of the arrester enabling calculations of voltages and currents as a function of arrester and pollution parameters is shown.

  4. Stabilization of gas-filled surge arrester’s characteristics by use of ionizing radiation

    Directory of Open Access Journals (Sweden)

    Brajović Dragan V.

    2012-01-01

    Full Text Available This paper investigates the stabilization of electrical discharges in gases by means of external ionizing radiation. Discharges in a gas-filled surge arrester model were studied in both passive and active regimes of the device. An originally developed model of the gas-filled surge arrester was used. Gas pressure and the interelectrode gap were the variable parameters in our measurements. Applied radiation types included α-particles, γ-rays, X-rays, and neutrons. Measurements were performed under highly controlled laboratory conditions. The combined measurement uncertainty of the applied procedure was estimated as being under the 5% level. The results obtained are followed by a theoretical explanation. The crucial result is the conclusion that ionizing radiation does not necessarily degrade the gas-filled surge arrester’s functionality but that it, rather, improves it under certain conditions.

  5. 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...

  6. Medvezhiy Glacier surge in 2011

    Directory of Open Access Journals (Sweden)

    V. M. Kotlyakov

    2012-01-01

    Full Text Available The paper presents results of monitoring of the Medvezhiy Glacier state for the period from its surge of 2001 to the last pulsation of 2011. This monitoring is performed based on the photographing made from the Russian section of the International Space Station. Features, used for prediction of the glacier last movement, are pointed out. The earlier determined characteristic property of the Medvezhiy Glacier change from a phase of recovering to that of its fast movement has been substantiated. Mean period of the glacier pulsations, estimated from observations for the last century, is 13.5 years. A surge of the glacier left tributary is recognized.

  7. 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

  8. Medvezhiy Glacier surge in 2011

    OpenAIRE

    V. M. Kotlyakov; L. V. Desinov

    2012-01-01

    The paper presents results of monitoring of the Medvezhiy Glacier state for the period from its surge of 2001 to the last pulsation of 2011. This monitoring is performed based on the photographing made from the Russian section of the International Space Station. Features, used for prediction of the glacier last movement, are pointed out. The earlier determined characteristic property of the Medvezhiy Glacier change from a phase of recovering to that of its fast movement has been substantiated...

  9. Lake Borgne Surge Barrier Study

    Science.gov (United States)

    2010-09-01

    Savant , and Darla C. McVan September 2010 Approved for public release; distribution is unlimited. ERDC/CHL TR-10-10 September 2010 Lake...Borgne Surge Barrier Study S. Keith Martin, Gaurav Savant , and Darla C. McVan Coastal and Hydraulics Laboratory U.S. Army Engineer Research and...conducted by Keith Martin, Dr. Gaurav Savant , and Darla C. McVan. This work was conducted at the Coastal and Hydraulics Laboratory (CHL) of the

  10. Switching surge overvoltages on a feeding system of a MAGLEV train; Jiki fujoshiki tetsudo no kidenkei ni okeru kaihei surge kaden`atsu

    Energy Technology Data Exchange (ETDEWEB)

    Muragishi, H. [Nippon Yusoki Co. Ltd., Kyoto (Japan); Nakamura, Y.; Muraoka, N.; Ametani, A. [Doshisha Univ., Kyoto (Japan)

    1997-04-20

    Discussions using simulations were given on surge overvoltages and earth fault surge overvoltage associated with operation of a section switchgear in a feeding system of a MAGLEV train. Results of the discussions may be summarized as follows: throw-in surge overvoltage caused by the section switchgear is about 25 kV at maximum on the coil and about 15 kV on the cable sheath. The coil overvoltage increases as the closer to 90 degrees the throw-in phase approaches, and the greater the power supply frequency increases. The cable sheath overvoltage, however, is not affected by these environments. Breaking surge overvoltage caused by the section switchgear reaches 115 kV on the coil and about the same value on the cable sheath when the breaking current is 50 A. Earth fault surge overvoltage due to cable fault is 24 kV at maximum on the coil, while it reaches 32 kV on the cable sheath. The cable sheath overvoltage depends largely on sheath installing conditions. These overvoltages can be suppressed sufficiently lower than insulation levels of each device by installing arresters. 17 refs., 18 figs.

  11. ASPECTS OF SURGE ARRESTERS’ MAXIMUM OPERATING VOLTAGE CHOICE FOR ELECTRICAL EQUIPMENT INSULATION PROTECTION IN 6-35 KV MAINS

    Directory of Open Access Journals (Sweden)

    Yu. N. Shumilov

    2013-09-01

    Full Text Available The paper shows that, in 6-35 kV mains, application of a non-linear surge arrester (SA with the maximum continuous admissible operating voltage which is 10% higher than the mains’ maximum operating voltage results in the SA protection from overheating and subsequent breakdown at nonnormable lifetime of single-phase arc faults.

  12. The worst moment of superposed surge wave in upstream series double surge tanks of hydropower station

    Science.gov (United States)

    Teng, Y.; Yang, J. D.; Guo, W. C.; Chen, J. P.

    2016-11-01

    It is a consensus to consider the superposed working conditions when calculating the surge wave in surge tank of hydropower station with long diversion tunnel. For the hydropower station with single surge tank, the method of determining the worst superposed moment is mature. However, for the hydropower station with upstream series double surge tanks, research in this field is still blank. Based on an engineering project, this paper investigated the worst moments and the control superposed working conditions about the maximum surge level and the minimum surge level of upstream series double surge tanks using numerical simulation. In addition, the incidence relations between the worst moment of superposed surge wave and the different areal array and distance between the two surge tanks are also carried out. The results showed that: With the decrease of the distance between auxiliary surge tank and upstream reservoir, the maximum values of the highest surge levels in the two surge tanks always reach close to but a little earlier than the bigger one time when the inflowing discharges of the two surge tanks reach the maximum. It is similar to the minimum values of lowest surge levels in the two surge tanks which also reach close to but a little later than the bigger one time when the outflowing discharges of the two surges reach the maximum. Moreover, the closer the area of auxiliary surge tank to the area of main surge tank is, the closer the worst moment to the bigger one time when inflow or outflow of the two surges reach the maximum will become.

  13. Surge-type glaciers: controls, processes and distribution

    OpenAIRE

    Sevestre, Heïdi

    2015-01-01

    Glacier surging is an internally triggered instability. Surge-type glaciers periodically alternate between long periods of slow flow (the quiescent phase) and short periods of fast flow (the surge phase). Surging yields down-glacier transport of mass and often results in large and sudden glacier advances.The surging phenomenon has always challenged the notion of normality in glacier flow dynamics. The mechanisms of surging remain poorly understood. Observation of different surge behaviors acr...

  14. Observing storm surges from satellite altimetry

    Science.gov (United States)

    Han, Guoqi

    2016-07-01

    Storm surges can cause catastrophic damage to properties and loss of life in coastal communities. Thus it is important to enhance our capabilities of observing and forecasting storm surges for mitigating damage and loss. In this presentation we show examples of observing storm surges around the world using nadir satellite altimetry, during Hurricane Sandy, Igor, and Isaac, as well as other cyclone events. The satellite observations are evaluated against tide-gauge observations and discussed for dynamic mechanisms. We also show the potential of a new wide-swath altimetry mission, the Surface Water and Ocean Topography (SWOT), for observing storm surges.

  15. Design of Lightning Arresters for Electrical Power Systems Protection

    Directory of Open Access Journals (Sweden)

    Shehab Abdulwadood

    2013-01-01

    Full Text Available This paper presents an overview of how the lightning strikes and their effects on power distribution systems can be modeled, where the results give a clear picture of how to eliminate the devastating impact, caused by lightning, by using lightning arresters. The program ATP-Draw (Alternative Transient Program was used to simulate the problem and was applied on a part of a power network.The simulation was done once when the lightning strikes a transmission line and a substation with no lightning arresters in use and once more with their use. The source of the lightning was represented by the ATP models (Type-15 surge function and Type-13 ramp function and the surge arrester was represented by the MOV-Type 92 component. The voltage was recorded at the substation 110/22 kV and at all loads in the electric network, and was drawn by the PlotXWin program. The results obtained indicate that the voltages induced by the lightning can reach values of the order of millions over insulation flashover levels for 22 kV equipment, where is clearly seen in Fig. 12 to 16 and Tab.10, which requires the installation of lightning arresters.

  16. 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

  17. 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...

  18. 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 inc

  19. Compression station anti-surge system considerations

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, Rainer; White, Robert C. [Solar Turbines Incorporated, Houston, TX (United States)

    2005-07-01

    Centrifugal compressor surge and its prevention have drawn significant attention in the literature. An important aspect of surge avoidance lies in the design of the compressor station and, in particular, the piping upstream and downstream of the compressor. Most anti-surge systems are perfectly capable of avoiding surge during normal operating conditions. However, unplanned emergency shutdowns present a significant challenge, and surge avoidance in these cases depends to a large degree on the station layout. Furthermore, the concepts used in the anti surge system (valves, piping, coolers) also impact the start-up of the station, or of individual units of the station. In this paper a simplified surge control system model is presented and used to develop simpler rules that help with proper sizing of upstream and downstream piping systems, as well as the necessary control element. Since the design of the surge control and recycle system also affects the start-up of units and stations, start-up considerations for stations with and without cooled recycle loops are discussed. (author)

  20. 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 flood-ri

  1. Conductive surge testing of circuits and systems

    Science.gov (United States)

    Richman, P.

    1980-01-01

    Techniques are given for conductive surge testing of powered electronic equipment. The correct definitions of common and normal mode are presented. Testing requires not only spike-surge generators with a suitable range of open-circuit voltage and short-circuit current waveshapes, but also appropriate means, termed couplers, for connecting test surges to the equipment under test. Key among coupler design considerations is minimization of fail positives resulting from reduction in delivered surge energy due to the coupler. Back-filters and the lines on which they are necessary, are considered as well as ground-fault and ground potential rise. A method for monitoring delivered and resulting surge waves is mentioned.

  2. Development and Evaluation of Storm Surge Ensemble Forecasting for the Philippines Using JMA Storm Surge Model

    Science.gov (United States)

    Lapidez, J. P. B.; Tablazon, J. P.; Lagmay, A. M. F. A.; Suarez, J. K. B.; Santiago, J. T.

    2014-12-01

    The Philippines is one of the countries most vulnerable to storm surge. It is located in the North-western Pacific basin which is the most active basin in the planet. An average of 20 tropical cyclones enters the Philippine area of responsibility (PAR) every year. The archipelagic nature of the country with regions having gently sloping coasts and shallow bays also contribute to the formation of extreme surges. Last November 2013, storm surge brought by super typhoon Haiyan severely damaged several coastal regions in the Visayan Islands. Haiyan left more than 6 300 casualties and damages amounting to more than $ 2 billion. Extreme storm surge events such as this highlight the need to establish a storm surge early warning system for the country. This study explores the development and evaluation of storm surge ensemble forecasting for the Philippines using the Japan Meteorological Agency (JMA) storm surge model. 36-hour, 24-hour, and 12-hour tropical cyclone forecasts are used to generate an ensemble storm surge forecast to give the most probable storm surge height at a specific point brought by an incoming tropical cyclone. The result of the storm surge forecast is compared to tide gauge record to evaluate the accuracy. The total time of computation and dissemination of forecast result is also examined to assess the feasibility of using the JMA storm surge model for operational purposes.

  3. Cardiac arrest in children

    Directory of Open Access Journals (Sweden)

    Tress Erika

    2010-01-01

    Full Text Available Major advances in the field of pediatric cardiac arrest (CA were made during the last decade, starting with the publication of pediatric Utstein guidelines, the 2005 recommendations by the International Liaison Committee on Resuscitation, and culminating in multicenter collaborations. The epidemiology and pathophysiology of in-hospital and out-of-hospital CA are now well described. Four phases of CA are described and the term "post-cardiac arrest syndrome" has been proposed, along with treatment goals for each of its four phases: immediate post-arrest, early post-arrest, intermediate and recovery phase. Hypothermia is recommended to be considered as a therapy for post-CA syndrome in comatose patients after CA, and large multicenter prospective studies are underway. We reviewed landmark articles related to pediatric CA published during the last decade. We present the current knowledge of epidemiology, pathophysiology and treatment of CA relevant to pre-hospital and acute care health practitioners.

  4. Pittsburgh Police Arrest Data

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Arrest data contains information on people taken into custody by City of Pittsburgh police officers. More serious crimes such as felony offenses are more likely to...

  5. Cardiac arrest - cardiopulmonary resuscitation

    Institute of Scientific and Technical Information of China (English)

    Basri Lenjani; Besnik Elshani; Nehat Baftiu; Kelmend Pallaska; Kadir Hyseni; Njazi Gashi; Nexhbedin Karemani; Ilaz Bunjaku; Taxhidin Zaimi; Arianit Jakupi

    2014-01-01

    Objective:To investigate application of cardiopulmonary resuscitation(CPR) measures within the golden minutes inEurope.Methods:The material was taken from theUniversityClinical Center ofKosovo -EmergencyCentre inPristina, during the two(2) year period(2010-2011).The collected date belong to the patients with cardiac arrest have been recorded in the patients' log book protocol at the emergency clinic.Results:During the2010 to2011 in the emergency center of theCUCK inPristina have been treated a total of269 patients with cardiac arrest, of whom159 or59.1% have been treated in2010, and110 patients or40.9% in2011.Of the269 patients treated in the emergency centre,93 or34.6% have exited lethally in the emergency centre, and176 or 65.4% have been transferred to other clinics.In the total number of patients with cardiac arrest, males have dominated with186 cases, or69.1%.The average age of patients included in the survey was56.7 year oldSD±16.0 years.Of the269 patients with cardiac arrest, defibrillation has been applied for93 or34.6% of patients.In the outpatient settings defibrillation has been applied for3 or3.2% of patients.Patients were defibrillated with application of one to four shocks. Of27 cases with who have survived cardiac arrest, none of them have suffered cardiac arrest at home,3 or11.1% of them have suffered cardiac arrest on the street, and24 or88.9% of them have suffered cardiac arrest in the hospital.5 out of27 patients survived have ended with neurological impairment.Cardiac arrest cases were present during all days of the week, but frequently most reported cases have been onMonday with32.0% of cases, and onFriday with24.5% of cases. Conclusions:All survivors from cardiac arrest have received appropriate medical assistance within10 min from attack, which implies that if cardiac arrest occurs near an institution health care(with an opportunity to provide the emergent health care) the rate of survival is higher.

  6. The dynamics of surge in compression systems

    Indian Academy of Sciences (India)

    A N Vishwanatha Rao; O N Ramesh

    2007-02-01

    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 drastically. Generally, all compression systems operate with a margin defined as the ‘surge margin’, and, consequently, system operational efficiency is lower. It is of interest to study compression-system surge to understand its dynamics in order to operate compression systems close to the instability for achieving high efficiency safely without encountering surge. Unsteady pressure data from a compression system, captured during surge oscillations, reveal many aspects of flow physics and are analysed to understand the surge dynamics of the system. A set of controlled experiments was conducted with a simple desktop experimental test set-up and essential aspects of surge dynamics have been characterised.

  7. 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

  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. Emergency department surge capacity: recommendations of the Australasian Surge Strategy Working Group.

    Science.gov (United States)

    Bradt, David A; Aitken, Peter; Fitzgerald, Gerry; Swift, Roger; O'Reilly, Gerard; Bartley, Bruce

    2009-12-01

    For more than a decade, emergency medicine (EM) organizations have produced guidelines, training, and leadership for disaster management. However, to date there have been limited guidelines for emergency physicians (EPs) needing to provide a rapid response to a surge in demand. The aim of this project was to identify strategies that may guide surge management in the emergency department (ED). A working group of individuals experienced in disaster medicine from the Australasian College for Emergency Medicine Disaster Medicine Subcommittee (the Australasian Surge Strategy Working Group) was established to undertake this work. The Working Group used a modified Delphi technique to examine response actions in surge situations and identified underlying assumptions from disaster epidemiology and clinical practice. The group then characterized surge strategies from their corpus of experience; examined them through available relevant published literature; and collated these within domains of space, staff, supplies, and system operations. These recommendations detail 22 potential actions available to an EP working in the context of surge, along with detailed guidance on surge recognition, triage, patient flow through the ED, and clinical goals and practices. The article also identifies areas that merit future research, including the measurement of surge capacity, constraints to strategy implementation, validation of surge strategies, and measurement of strategy impacts on throughput, cost, and quality of care.

  10. Glacier surge mechanism: 1982-1983 surge of variegated glacier, alaska.

    Science.gov (United States)

    Kamb, B; Raymond, C F; Harrison, W D; Engelhardt, H; Echelmeyer, K A; Humphrey, N; Brugman, M M; Pfeffer, T

    1985-02-01

    The hundredfold speedup in glacier motion in a surge of the kind the kind that took place in Variegated Glacier in 1982-1983 is caused by the buildup of high water pressure in the basal passageway system, which is made possible by a fundamental and pervasive change in the geometry and water-transport characteristics of this system. The behavior of the glacier in surge has many remarkable features, which can provide clues to a detailed theory of the surging process. The surge mechanism is akin to a proposed mechanism of overthrust faulting.

  11. The European Arrest Warrant

    Directory of Open Access Journals (Sweden)

    Minodora-Ioana Balan-Rusu

    2012-05-01

    Full Text Available In the paper it is generally examined the institution of the European arrest warrant according to the latest changes and additions through the adoption of a new European legislative act. The paper is a continuation of research in the area of judicial cooperation in criminal matters in the European Union. It may be useful to the judicial bodies with the responsibilities of issuing and executing a specific European arrest warrant and to academics and students in law schools. The research results, the essential contribution, the originality consist of the general examination of the institution, the critical remarks and proposals for amending and completing certain provisions insufficiently clear.

  12. 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

  13. 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

  14. The European arrest warrant

    Directory of Open Access Journals (Sweden)

    Đurđić Vojislav

    2012-01-01

    Full Text Available The paper portrays the new European Union extradition system, established by the Framework Decision on the European arrest warrant and the surrender procedures between Member States of 2002. In the introductory remarks, the author explains the formation and development of the traditional extradition procedure, depicts relevant legal sources, and points to its flaws, which boil down to tardiness and inefficiency. The main author's standpoint is that the European arrest warrant is based on mutual trust in the member-states' legal systems, and that it depoliticizes the extradition procedure by transforming interstate cooperation into cooperation between member - states' law enforcement authorities. On these grounds, the author determines the nature of this new legal institute, that introduces radical changes into the paradigm of the classical extradition, and explains its main features as well as the scope of application. Further on, the paper explores the conditions for issuance of the European arrest warrant, which are proscribed by negative formulations - as absolute and relative obstacles for extradition. Finally, the author explains the standardized formal elements of the European arrest warrant content, which should make its application easier and more expeditious.

  15. 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.

    ) for storm surge forecasting at the eastern coast of India. Flather (1994) has applied another analytical model of Holland (1980) for wind and pressure fields in the case of surge simulation, forced by April 1991 Bangladesh storm. The basic atmospheric... parameters remain the same in all the parameterization schemes of storm wind field. Storm Surge Model Storm surge operational models are in use for a long time for forecasting and warning of storm surge disasters bordering the coasts in the parts of northern...

  16. Runway Arrested Landing Site (RALS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Runway Arrested Landing Site includes an underground complex located on a Mod 2, Mod 3, and Mod 3+ arresting gear and are located under the runway and accurately...

  17. From solitary wave to traveling surge

    Institute of Scientific and Technical Information of China (English)

    宋礼庭

    1995-01-01

    The solution of kinetic Alfven wave under action of anomalous resistance has two branches: the slow wave, VPsurge and the fast wave VP>VA cosθ will be in a wave-broken state. Such traveling surge structure is a typical self-organization phenomenon and its wave form is determined by parameter β which represents the magnitude of resistance. High β leads to shock-like structure and low β to the appearance of some solitary waves in front of the shock. According to the study on solitary wave, shock wave and traveling surge in conjunction with self-organization of nonlinear dynamics, a general definition of wave can be given.

  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. Computer-assisted mapping of pyroclastic surges.

    Science.gov (United States)

    Malin, M C; Sheridan, M F

    1982-08-13

    Volcanic hazard maps of surge boundaries and deposit thickness can be created by using a simplified eruption model based on an "energy line" concept of pyroclastic surge and flow emplacement. Computer image-processing techniques may be used to combine three-dimensional representations of the energy relations of pyroclasts moving under the influence of gravity (defined by an "energy cone") with digital topographic models of volcanoes to generate theoretical hazard maps. The deposit boundary and thickness calculated for the 18 May 1980 eruption of Mount St. Helens are qualitatively similar to those actually observed.

  20. Adaptive Mesh Refinement for Storm Surge

    CERN Document Server

    Mandli, Kyle T

    2014-01-01

    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.

  1. Experimental investigation of steep-front short duration (SFSD) surge effects on power systems components

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D.B. (Mississippi State Univ., MS (United States). Dept. of Electrical and Computer Engineering)

    1992-05-01

    Results are reported from experiments in which steep-front, short- duration (SFSD) voltage impulses were imposed on various electrical distribution components. These pulses were generated by switching a section of charged, high voltage coaxial cable across the component under study. Components included underground distribution cable, terminators, insulators and arresters. SFSD voltage needed to flashover 15 kV polyethylene cable with a single pulse is approximately 625 kV peak. Strength of polyethylene cable decreases with increasing number of SFSD pulses, indicating cumulative degradation of the polymer. For 15 kV and 25 kV cable terminators, the SFSD CFO was over twice the rated standard lightning BIL for the same units. Similarly, porcelain suspension insulators required more than a doubling of voltage to decrease time to flashover from 1 microsecond to .1 microsecond. Arresters were found to respond rapidly to steep-front current pulses, but the arrester material itself was found to result in a higher discharge voltage for SFSD pulses. Arresters also showed a delay in turn-on of current following the arrival of a steep-front voltage surge.

  2. Storm surge and river interaction in etuaries

    Science.gov (United States)

    Maskell, J.

    2012-04-01

    In coastal areas, particularly in regions developed on estuaries, extreme river flow can combine with storm surges to present a combined hazard. This combined risk is likely to be more prominent in estuaries where fluvial fresh water input comes from catchments in hilly regions where the dependence of extreme river discharge and sea level elevation can be most statistically significant (Svensson and Jones, 2004). The risk associated with these combined coastal hazards could increase due to climate change if there were an increase in the frequency of extreme weather events. The global (IPCC, 2007) and local (Woodworth et al., 2009) rise in mean sea-level will increase the magnitude of extreme sea levels and surges will act on a higher coastal sea level and therefore increase the risk to coastal property and infrastructure. This may be associated with an increase in precipitation during extreme storm events which will have a large impact on river flooding. Therefore, the need for accurate operational forecasting of storm events will increase with the focus shifting to changes in the extreme 'tail end' of the distribution of storm events. Ideally an operational model that integrates storm surge, wave and fluvial forecasting with inundation and simulates their combined influence would be most effective for planning with respect to flood plain development, evacuation and flood defence. Current operational storm surge models are typically based on two-dimensional depth-averaged shallow water equations (Flather, 2000). Inundation models often use an approximation of the original shallow water equations which neglect the inertial terms (Prestininzi et al., 2011). These 2D flood plain inundation models are often coupled with a 1D model of the main channel of a river or estuary which permits the exchange of mass but assumes a limited exchange of momentum (Bates et al., 2005). A finite volume model (FVCOM) is used to investigate the combined influence of storm surge and river

  3. Positive feedback stabilization of centrifugal compressor surge

    NARCIS (Netherlands)

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

    2002-01-01

    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 stabiliz

  4. 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

  5. Synthetic Fentanyl Fueling Surge in Overdose Deaths: CDC

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_160618.html Synthetic Fentanyl Fueling Surge in Overdose Deaths: CDC U.S. Surgeon ... News) -- Deaths from overdoses of the synthetic narcotic fentanyl have surged in recent years, U.S. health officials ...

  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...

  7. Numerical Evaluation of Storm Surge Indices for Public Advisory Purposes

    Science.gov (United States)

    Bass, B.; Bedient, P. B.; Dawson, C.; Proft, J.

    2016-12-01

    After the devastating hurricane season of 2005, shortcomings with the Saffir-Simpson Hurricane Scale's (SSHS) ability to characterize a tropical cyclones potential to generate storm surge became widely apparent. As a result, several alternative surge indices were proposed to replace the SSHS, including Powell and Reinhold's Integrated Kinetic Energy (IKE) factor, Kantha's Hurricane Surge Index (HSI), and Irish and Resio's Surge Scale (SS). Of the previous, the IKE factor is the only surge index to-date that truly captures a tropical cyclones integrated intensity, size, and wind field distribution. However, since the IKE factor was proposed in 2007, an accurate assessment of this surge index has not been performed. This study provides the first quantitative evaluation of the IKEs ability to serve as a predictor of a tropical cyclones potential surge impacts as compared to other alternative surge indices. Using the tightly coupled ADvanced CIRCulation and Simulating WAves Nearshore models, the surge and wave responses of Hurricane Ike (2008) and 78 synthetic tropical cyclones were evaluated against the SSHS, IKE, HSI and SS. Results along the upper TX coast of the Gulf of Mexico demonstrate that the HSI performs best in capturing the peak surge response of a tropical cyclone, while the IKE accounting for winds greater than tropical storm intensity (IKETS) provides the most accurate estimate of a tropical cyclones regional surge impacts. These results demonstrate that the appropriate selection of a surge index ultimately depends on what information is of interest to be conveyed to the public and/or scientific community.

  8. 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

  9. Earth Observation in aid of surge monitoring and forecasting: ESA's eSurge Project

    Science.gov (United States)

    Harwood, Phillip; Cipollini, Paolo; Snaith, Helen; Høyer, Jacob; Dwyer, Ned; Dunne, Declan; Stoffelen, Ad; Donlon, Craig

    2013-04-01

    The understanding and realistic modelling of surges supports both preparation and mitigation activities and should eventually bring enormous societal benefits, especially to some of the world's poorest countries. Earth Observation data from satellites have an important role to play in storm surge monitoring and forecasting, but the full uptake of these data by the users (such as environmental agencies and tidal prediction centres) must be first encouraged by showcasing their usefulness, and then supported by providing easy access. The European Space Agency has recognized the above needs and, through its Data User Element (DUE) programme, has initiated in 2011 the eSurge project, whose aims are: a) to contribute through Earth Observation to an integrated approach to storm surge, wave, sea-level and flood forecasting as part of a wider optimal strategy for building an improved forecast and warning capability for coastal inundation; and b) to increase the use of the advanced capabilities of ESA and other satellite data for storm surge applications. The project is led by Logica UK, with NOC (UK), DMI (Denmark), CMRC (Ireland) and KNMI (Netherlands) as scientific partners. eSurge aims to provide easy access to a wide range of relevant data for a range of historical surge events, as well as performing a series of experiments to demonstrate the value of this data, and running workshops and training courses to help users make use of the available data. The eSurge database of Earth Observation and in situ measurements for past surge events is now publicly available. In 2013 the project moves into its service demonstration phase, adding more data and events, including a demonstration near real time service. The project works closely with its users in order to meet their needs and to maximise the return of this data. A novel dataset provided by eSurge is coastal altimetry. Coastal altimetry has a prominent role to play as it measures directly the total water level envelope

  10. The use of coastal altimetry to support storm surge studies in project eSurge

    Science.gov (United States)

    Cipollini, P.; Harwood, P.; Snaith, H.; Vignudelli, S.; West, L.; Zecchetto, S.; Donlon, C.

    2012-04-01

    One of the most promising applications of the new field of coastal altimetry, i.e. the discipline aiming to recover meaningful estimates of geophysical parameters (sea level, significant wave height and wind speed) from satellite altimeter data in the coastal zone, is the study of storm surges. The understanding and realistic modelling of surges supports both preparation and mitigation activities and should eventually bring enormous societal benefits, especially to some of the world's poorest countries (like Bangladesh). Earth Observation data have an important role to play in storm surge monitoring and forecasting, but the full uptake of these data by users (such as environmental agencies and tidal prediction centres) must first be encouraged by showcasing their usefulness, and then supported by providing easy access. Having recognized the above needs, The European Space Agency has recently launched a Data User Element (DUE) project called eSurge. The main purposes of eSurge are a) to contribute to an integrated approach to storm surge, wave, sea-level and flood forecasting through Earth Observation, as part of a wider optimal strategy for building an improved forecast and early warning capability for coastal inundation; and b) to increase the use of the advanced capabilities of ESA and other satellite data for storm surge applications. The project is led by Logica UK, with NOC (UK), DMI (Denmark), CMRC (Ireland) and KNMI (Netherlands) as scientific partners. A very important component of eSurge is the development, validation and provision of dedicated coastal altimetry products, which is the focus of the present contribution. Coastal altimetry has a prominent role to play as it measures the total water level envelope directly, and this is one of the key quantities required by storm surge applications and services. But it can also provide important information on the wave field in the coastal strip, which helps the development of more realistic wave models that in

  11. Guiding Surge Reduction Strategies via Characterization of Coastal Surge Propagation and Internal Surge Generation within a Complex Bay/Estuary System, Galveston Bay, TX

    Science.gov (United States)

    Bass, B.; Torres, J.; Irza, N.; Bedient, P. B.; Dawson, C.; Proft, J.

    2015-12-01

    In this study, Hurricane Ike (2008) and a suite of synthetic storms are simulated in order to evaluate how different hurricane landfalls, wind intensities, and radius to maximum winds influence the surge response in complex semi-enclosed bays such as Galveston Bay, located along the Texas Gulf Coast. The Advanced CIRCulation and Simulating Waves Nearshore (ADCIRC+SWAN) models are employed to quantify surge in terms of its relative coastal contributions that propagate across barrier islands and tidal inlets and subsequently into Galveston Bay, the surge generated locally within the Bay itself, and the interaction between these coastal and local components of surge. Results from this research will further the current understanding of surge interactions in bay systems and guide coastal engineering surge reduction projects that need to consider multiple lines of defense to protect complex bay/estuary systems such as Galveston Bay, TX.

  12. ECPR for Refractory Out-Of-Hospital Cardiac Arrest

    Science.gov (United States)

    2017-05-17

    Cardiac Arrest; Heart Arrest; Sudden Cardiac Arrest; Cardiopulmonary Arrest; Death, Sudden, Cardiac; Cardiopulmonary Resuscitation; CPR; Extracorporeal Cardiopulmonary Resuscitation; Extracorporeal Membrane Oxygenation

  13. 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.

  14. Hypergravity induced prolactin surge in female rats

    Science.gov (United States)

    Megory, E.; Oyama, J.

    1985-01-01

    Acute initial exposure to hypergravity (HG) was previously found to induce prolonged diestrous in rats, which was followed by return to normal estrous cycling upon more prolonged exposure to continuous HG. Bromergocryptine was found to prevent this prolonged diestrous. In this study it is found that in female rats 20 h of 3.14 G exposure (D-1 1200 h until D-2 0800 h) can induce prolactin surge at D-2 1600 h. Shorter exposure time (8 h), or exposure during a different part of the estrous cycle (19 h: from D-1 0700 h until D-2 0200 h) could not elicit this prolactin surge. Similar exposure of male rats of HG did not alter significantly their prolactin levels. It is possible that the hypothalamus of male and female rats responds differently to stimulation by HG.

  15. Probabilistic Storm Surge Hazard Assessment in Martinique

    Science.gov (United States)

    Krien, Yann; Dudon, Bernard; Sansorgne, Eliot; Roger, Jean; Zahibo, Narcisse; Roquelaure, Stevie

    2013-04-01

    Located at the center of the Lesser Antilles, Martinique is under the threat of hurricanes formed over the warm tropical waters of the Atlantic Ocean and Caribbean Sea. These events can be extremely costly in terms of human, property, and economic losses. Storm surge hazard studies are hence required to provide guidance to emergency managers and decision-makers. A few studies have been conducted so far in the French Lesser Antilles, but they mainly rely on scarce historical data of extreme sea levels or numerical models with coarse resolutions. Recent progress in statistical techniques for generating large number of synthetic hurricanes as well as availability of high-resolution topographic and bathymetric data (LIDAR) and improved numerical models enables us today to conduct storm surge hazard assessment studies with much more accuracy. Here we present a methodology to assess cyclonic surge hazard in Martinique both at regional and local scales. We first simulate the storm surges that would be induced by a large set of potential events generated by the statistical/deterministic models of Emanuel et al. [2006]. We use the ADCIRC-SWAN coupled models (Dietrich et al 2012) to simulate inundation inland with grid resolutions of up to 50-100m in the coastal area for the whole island.These models are validated against observations during past events such as hurricane Dean in 2007. The outputs can then be used in some specific sites to force higher resolution models for crisis management and local risk assessment studies. This work is supported by the INTERREG IV « Caribbean » program TSUNAHOULE.

  16. Cardiac arrest – cardiopulmonary resuscitation

    Directory of Open Access Journals (Sweden)

    Basri Lenjani

    2014-01-01

    Conclusions: All survivors from cardiac arrest have received appropriate medical assistance within 10 min from attack, which implies that if cardiac arrest occurs near an institution health care (with an opportunity to provide the emergent health care the rate of survival is higher.

  17. Design and Characterization of a Centrifugal Compressor Surge Test Rig

    Directory of Open Access Journals (Sweden)

    Kin Tien Lim

    2011-01-01

    Full Text Available A detailed description of a new centrifugal compressor surge test rig is presented. The objective of the design and development of the rig is to study the surge phenomenon in centrifugal compression systems and to investigate a novel method of surge control by active magnetic bearing servo actuation of the impeller axial tip clearance. In this paper, we focus on the design, initial setup, and testing of the rig. The latter two include the commissioning of the rig and the experimental characterization of the compressor performance. The behavior of the compressor during surge is analyzed by driving the experimental setup into surge. Two fundamental frequencies, 21 Hz and 7 Hz, connected to the surge oscillation in the test rig are identified, and the observed instability is categorized according to the intensity of pressure fluctuations. Based on the test results, the excited pressure waves are clearly the result of surge and not stall. Also, they exhibit the characteristics of mild and classic surge instead of deep surge. Finally, the change in the compressor performance due to variation in the impeller tip clearance is experimentally examined, and the results support the potential of the tip clearance modulation for the control of compressor surge. This is the first such demonstration of the feasibility of surge control of a compressor using active magnetic bearings.

  18. 15kV系统避雷器的选择%Selection of Arresters for15kV System

    Institute of Scientific and Technical Information of China (English)

    徐世宇

    2012-01-01

    本文介绍了无间隙金属氧化物避雷器的特点,并对15kV中性点非直接接地系统中,民用建筑的变配电所内及高压柜中安装的避雷器的参数选择进行探讨。%This paper mainly describes the characteristics of metal oxide gapless surge attesters and discusses the selection of parameters for surge arresters in 15kV neutral point nondirect ground systems, the substation of civil building and highvoltage switchgear.

  19. Climatic Controls on the Distribution of Surging Glaciers

    Science.gov (United States)

    Sevestre, H.; Benn, D.

    2012-12-01

    Surge-type glaciers are scattered in a non-random fashion, gathered in clusters in some glaciated regions. One group of clusters forms an Arctic and Sub-Arctic 'crescent', spanning from Alaska-Yukon, through Arctic Canada, West and East Greenland, Iceland, Svalbard and Novaya Zemlya. Another cluster occurs in western High Asia, including the Karakoram Mountains. Although several studies have assessed the influence of environmental controls on surging, so far none has provided a satisfactory explanation for the geographical location of these clusters. The distribution of such glaciers undoubtedly holds the keys of a better understanding on the controls on surging behaviour. For this study, two glacier populations are considered. First, a global inventory of glacier surges has been compiled, based on published observations, field reports and remote sensing studies. This digital database is structured in three tables, respectively providing information on the location and geometry of each surge-type glacier, surge dates and magnitude, and methodology employed at the time of observation. This global dataset is compared to the population of "non-surge-type glaciers" based on the Randolph Glacier Inventory version 2.0 excluding the inventoried surging glaciers. In both populations, glaciers are classified depending on their geometry and thermal regime. Downscaled climatic datasets are used to identify climatic envelopes associated with clusters of surging glaciers. We identified which environments are most prone to be associated to glacier surging, and examined the influence of these parameters on the surge cycle duration and character. These results emphasize the importance of external controls on surging (as against individual surges), and promote the need to study this behaviour in the frame of an energy-balance budget.

  20. Acquired Upper Extremity Growth Arrest.

    Science.gov (United States)

    Gauger, Erich M; Casnovsky, Lauren L; Gauger, Erica J; Bohn, Deborah C; Van Heest, Ann E

    2017-01-01

    This study reviewed the clinical history and management of acquired growth arrest in the upper extremity in pediatric patients. The records of all patients presenting from 1996 to 2012 with radiographically proven acquired growth arrest were reviewed. Records were examined to determine the etiology and site of growth arrest, management, and complications. Patients with tumors or hereditary etiology were excluded. A total of 44 patients (24 boys and 20 girls) with 51 physeal arrests who presented at a mean age of 10.6 years (range, 0.8-18.2 years) were included in the study. The distal radius was the most common site (n=24), followed by the distal humerus (n=8), metacarpal (n=6), distal ulna (n=5), proximal humerus (n=4), radial head (n=3), and olecranon (n=1). Growth arrest was secondary to trauma (n=22), infection (n=11), idiopathy (n=6), inflammation (n=2), compartment syndrome (n=2), and avascular necrosis (n=1). Twenty-six patients (59%) underwent surgical intervention to address deformity caused by the physeal arrest. Operative procedures included ipsilateral unaffected bone epiphysiodesis (n=21), shortening osteotomy (n=10), lengthening osteotomy (n=8), excision of physeal bar or bone fragment (n=2), angular correction osteotomy (n=1), and creation of single bone forearm (n=1). Four complications occurred; 3 of these required additional procedures. Acquired upper extremity growth arrest usually is caused by trauma or infection, and the most frequent site is the distal radius. Growth disturbances due to premature arrest can be treated effectively with epiphysiodesis or osteotomy. In this series, the specific site of anatomic growth arrest was the primary factor in determining treatment. [Orthopedics. 2017; 40(1):e95-e103.]. Copyright 2016, SLACK Incorporated.

  1. Metoclopramide-induced cardiac arrest

    Directory of Open Access Journals (Sweden)

    Martha M. Rumore

    2011-11-01

    Full Text Available The authors report a case of cardiac arrest in a patient receiving intravenous (IV metoclopramide and review the pertinent literature. A 62-year-old morbidly obese female admitted for a gastric sleeve procedure, developed cardiac arrest within one minute of receiving metoclopramide 10 mg via slow intravenous (IV injection. Bradycardia at 4 beats/min immediately appeared, progressing rapidly to asystole. Chest compressions restored vital function. Electrocardiogram (ECG revealed ST depression indicative of myocardial injury. Following intubation, the patient was transferred to the intensive care unit. Various cardiac dysrrhythmias including supraventricular tachycardia (SVT associated with hypertension and atrial fibrillation occurred. Following IV esmolol and metoprolol, the patient reverted to normal sinus rhythm. Repeat ECGs revealed ST depression resolution without pre-admission changes. Metoclopramide is a non-specific dopamine receptor antagonist. Seven cases of cardiac arrest and one of sinus arrest with metoclopramide were found in the literature. The metoclopramide prescribing information does not list precautions or adverse drug reactions (ADRs related to cardiac arrest. The reaction is not dose related but may relate to the IV administration route. Coronary artery disease was the sole risk factor identified. According to Naranjo, the association was possible. Other reports of cardiac arrest, severe bradycardia, and SVT were reviewed. In one case, five separate IV doses of 10 mg metoclopramide were immediately followed by asystole repeatedly. The mechanism(s underlying metoclopramide’s cardiac arrest-inducing effects is unknown. Structural similarities to procainamide may play a role. In view of eight previous cases of cardiac arrest from metoclopramide having been reported, further elucidation of this ADR and patient monitoring is needed. Our report should alert clinicians to monitor patients and remain diligent in surveillance and

  2. [Arrest of maturation in spermatogenesis].

    Science.gov (United States)

    Francavilla, S; Bellocci, M; Martini, M; Bruno, B; Moscardelli, S; Fabbrini, A; Properzi, G

    1982-07-30

    The ultrastructural aspects of the germinal epithelium of 10 infertile men affected by maturative arrest of spermatogenesis were studied. We noted an increased number of malformed germinal cells. Marginal nuclear vescicles were present in spermatogonia of patients affected by spermatogonial arrest. The few spermatid present in the germinal epithelium of the patients affected by a spermatidic arrest presented changes of the nuclear condensation, the acrosome, and the tail. The Sertoli cells presented an immature aspect of the nucleus and changes of the "mantle". A possible correlation between the Sertoli cells changes and the altered spermatogenesis was proposed.

  3. 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.

  4. Atlantic hurricane surge response to geoengineering.

    Science.gov (United States)

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

    2015-11-10

    Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges.

  5. Glacier surge after ice shelf collapse.

    Science.gov (United States)

    De Angelis, Hernán; Skvarca, Pedro

    2003-03-07

    The possibility that the West Antarctic Ice Sheet will collapse as a consequence of ice shelf disintegration has been debated for many years. This matter is of concern because such an event would imply a sudden increase in sea level. Evidence is presented here showing drastic dynamic perturbations on former tributary glaciers that fed sections of the Larsen Ice Shelf on the Antarctic Peninsula before its collapse in 1995. Satellite images and airborne surveys allowed unambiguous identification of active surging phases of Boydell, Sjögren, Edgeworth, Bombardier, and Drygalski glaciers. This discovery calls for a reconsideration of former hypotheses about the stabilizing role of ice shelves.

  6. An airline cardiac arrest program

    National Research Council Canada - National Science Library

    O'Rourke, M F; Donaldson, E; Geddes, J S

    1997-01-01

    ...) available for use on airline passengers with cardiac arrest. AEDs were installed on international Qantas aircraft and at major terminals, selected crew were trained in their use, and all crew members were trained in cardiopulmonary resuscitation...

  7. Design and Characterization of a Centrifugal Compressor Surge Test Rig

    OpenAIRE

    2011-01-01

    A detailed description of a new centrifugal compressor surge test rig is presented. The objective of the design and development of the rig is to study the surge phenomenon in centrifugal compression systems and to investigate a novel method of surge control by active magnetic bearing servo actuation of the impeller axial tip clearance. In this paper, we focus on the design, initial setup, and testing of the rig. The latter two include the commissioning of the rig and the experimental characte...

  8. Performance Comparison of the European Storm Surge Models and Chaotic Model in Forecasting Extreme Storm Surges

    Science.gov (United States)

    Siek, M. B.; Solomatine, D. P.

    2009-04-01

    Storm surge modeling has rapidly developed considerably over the past 30 years. A number of significant advances on operational storm surge models have been implemented and tested, consisting of: refining computational grids, calibrating the model, using a better numerical scheme (i.e. more realistic model physics for air-sea interaction), implementing data assimilation and ensemble model forecasts. This paper addresses the performance comparison between the existing European storm surge models and the recently developed methods of nonlinear dynamics and chaos theory in forecasting storm surge dynamics. The chaotic model is built using adaptive local models based on the dynamical neighbours in the reconstructed phase space of observed time series data. The comparison focused on the model accuracy in forecasting a recently extreme storm surge in the North Sea on November 9th, 2007 that hit the coastlines of several European countries. The combination of a high tide, north-westerly winds exceeding 50 mph and low pressure produced an exceptional storm tide. The tidal level was exceeded 3 meters above normal sea levels. Flood warnings were issued for the east coast of Britain and the entire Dutch coast. The Maeslant barrier's two arc-shaped steel doors in the Europe's biggest port of Rotterdam was closed for the first time since its construction in 1997 due to this storm surge. In comparison to the chaotic model performance, the forecast data from several European physically-based storm surge models were provided from: BSH Germany, DMI Denmark, DNMI Norway, KNMI Netherlands and MUMM Belgium. The performance comparison was made over testing datasets for two periods/conditions: non-stormy period (1-Sep-2007 till 14-Oct-2007) and stormy period (15-Oct-2007 till 20-Nov-2007). A scalar chaotic model with optimized parameters was developed by utilizing an hourly training dataset of observations (11-Sep-2005 till 31-Aug-2007). The comparison results indicated the chaotic

  9. Comparison of durability requirements of new IEEE, CSA and IEC standards for metal-oxide station arrester

    Energy Technology Data Exchange (ETDEWEB)

    Lat, M.V.; Kirkby, P.; Ringler, K.; Kortschinski, J.; Erven, C. [Ontario Hydro Technologies, Toronto, ON (Canada)

    1998-04-01

    Three standards exist for metal-oxide station class surge arresters. These are the IEEE, CSA and IEC standards. The apparent incompatibilities of the standards make the task of arrester specification by utility engineers difficult. This study was conducted to analyze and compare the severity of the durability requirements of the the three standards under different service conditions. The comparison was conducted on the basis of the maximum calculated temperature rise of the valve elements. A validated electrothermal arrester modeling program was used for the analysis. Six different arrester designs, representing all IEC surge arrester line discharge classifications were used in the study. It was concluded that the electrothermal durability requirements of all three standards were very similar. The most critical test procedure, the 2-pulse transmission line discharge test, is virtually identical in all three standards in preheating the test sample to 60 degrees C and applying two rectangular current pulses. The major difference between the standards was in defining the magnitude of the current pulse and the energy it delivers into the test sample. 16 refs., 45 tabs., 77 figs., 3 appendices.

  10. Simplified Storm Surge Simulations Using Bernstein Polynomials

    Science.gov (United States)

    Beisiegel, Nicole; Behrens, Jörn

    2016-04-01

    Storm surge simulations are vital for forecasting, hazard assessment and eventually improving our understanding of Earth system processes. Discontinuous Galerkin (DG) methods have recently been explored in that context, because they are locally mass-conservative and in combination with suitable robust nodal filtering techniques (slope limiters) positivity-preserving and well-balanced for the still water state at rest. These filters manipulate interpolation point values in every time step in order to retain the desirable properties of the scheme. In particular, DG methods are able to represent prognostic variables such as the fluid height at high-order accuracy inside each element (triangle). For simulations that include wetting and drying, however, the high-order accuracy will destabilize the numerical model because point values on quadrature points may become negative during the computation if they do not coincide with interpolation points. This is why the model that we are presenting utilizes Bernstein polynomials as basis functions to model the wetting and drying. This has the advantage that negative pointvalues away from interpolation points are prevented, the model is stabilized and no additional time step restriction is introduced. Numerical tests show that the model is capable of simulating simplified storm surges. Furthermore, a comparison of model results with third-order Bernstein polynomials with results using traditional nodal Lagrange polynomials reveals an improvement in numerical convergence.

  11. Hospital bioterrorism planning and burn surge.

    Science.gov (United States)

    Kearns, Randy D; Myers, Brent; Cairns, Charles B; Rich, Preston B; Hultman, C Scott; Charles, Anthony G; Jones, Samuel W; Schmits, Grace L; Skarote, Mary Beth; Holmes, James H; Cairns, Bruce A

    2014-01-01

    On the morning of June 9, 2009, an explosion occurred at a manufacturing plant in Garner, North Carolina. By the end of the day, 68 injured patients had been evaluated at the 3 Level I trauma centers and 3 community hospitals in the Raleigh/Durham metro area (3 people who were buried in the structural collapse died at the scene). Approximately 300 employees were present at the time of the explosion, when natural gas being vented during the repair of a hot water heater ignited. The concussion from the explosion led to structural failure in multiple locations and breached additional natural gas, electrical, and ammonia lines that ran overhead in the 1-story concrete industrial plant. Intent is the major difference between this type of accident and a terrorist using an incendiary device to terrorize a targeted population. But while this disaster lacked intent, the response, rescue, and outcomes were improved as a result of bioterrorism preparedness. This article discusses how bioterrorism hospital preparedness planning, with an all-hazards approach, became the basis for coordinated burn surge disaster preparedness. This real-world disaster challenged a variety of systems, hospitals, and healthcare providers to work efficiently and effectively to manage multiple survivors. Burn-injured patients served as a focus for this work. We describe the response, rescue, and resuscitation provided by first responders and first receivers as well as efforts made to develop burn care capabilities and surge capacity.

  12. Tide and skew surge independence: New insights for flood risk

    Science.gov (United States)

    Williams, Joanne; Horsburgh, Kevin J.; Williams, Jane A.; Proctor, Robert N. F.

    2016-06-01

    Storm surges are a significant hazard to coastal communities around the world, putting lives at risk and costing billions of dollars in damage. Understanding how storm surges and high tides interact is crucial for estimating extreme water levels so that we can protect coastal communities. We demonstrate that in a tidal regime the best measure of a storm surge is the skew surge, the difference between the observed and predicted high water within a tidal cycle. Based on tide gauge records spanning decades from the UK, U.S., Netherlands, and Ireland we show that the magnitude of high water exerts no influence on the size of the most extreme skew surges. This is the first systematic proof that any storm surge can occur on any tide, which is essential for understanding worst-case scenarios. The lack of surge generation dependency on water depth emphasizes the dominant natural variability of weather systems in an observation-based analysis. Weak seasonal relationships between skew surges and high waters were identified at a minority of locations where long-period changes to the tidal cycle interact with the storm season. Our results allow advances to be made in methods for estimating the joint probabilities of storm surges and tides.

  13. Auroral radio absorption and the westward travelling surge

    Energy Technology Data Exchange (ETDEWEB)

    Collis, P.N.; Korth, A.

    1983-11-01

    Measurements from a network of riometers during the passage of an auroral westward traveling surge are presented. These show that the energetic precipitation producing the radio absorption expands in an almost identical fashion to the softer precipitation associated with the visible surge; but it is delayed by about two minutes with respect to the surge. The delay is interpreted as a hardening of the precipitating electron spectrum as the surge goes by. Simultaneous observations of electrons at synchronous orbit are shown to support this conclusion. 24 references.

  14. Over 400 previously undocumented Svalbard surge-type glaciers identified

    Science.gov (United States)

    Farnsworth, Wesley R.; Ingólfsson, Ólafur; Retelle, Michael; Schomacker, Anders

    2016-07-01

    Identifying glaciers that exhibit surge-type behavior is important when using evidence of ice front fluctuations as a proxy for reconstructing past climate oscillations. This study identifies previously undocumented surge-type glaciers in Svalbard, based on the presence of crevasse squeeze ridges in glacier forelands. Crevasse squeeze ridges are landforms suggested to be unique to surging glacier land systems. Estimates vary greatly as to the actual percentage of surge-type glaciers in Svalbard, and consequently their distribution pattern is poorly understood. A detailed survey of recent (2008-2012), high-resolution aerial imagery from TopoSvalbard, provided by the Norwegian Polar Institute, allowed for a survey of all the glacier forelands in Svalbard. Before our study, 277 individual glaciers in Svalbard have been documented to exhibit surge behavior. By using crevasse squeeze ridges as indicators of surge behavior, we have identified 431 additional glaciers that have surged. We suggest that this is a modest value as the unique surge landforms were not visible in approximately one-third of the forelands with documented surge histories. Limits to the crevasse squeeze ridge technique are presented and potential controlling factors for crevasse squeeze ridge formation/preservation are discussed.

  15. On the magnitude and frequency of Karakoram Glacier surges

    Directory of Open Access Journals (Sweden)

    D. J. Quincey

    2013-10-01

    Full Text Available The return periods of Karakoram glacier surges are almost entirely unknown. Here, we present evidence of an historic surge of the Khurdopin Glacier that began in the mid-1970s and peaked in 1979. Measured surface displacements reached > 5 km yr–1, two orders of magnitude faster than during quiescence and twice as large as any previously recorded velocity in the region. The Khurdopin Glacier next surged in the late-1990s, equating to a return period of 20 yr. Surge activity in the region needs to be better understood if accurate mass balance assessments of Hindu-Kush–Karakoram–Himalaya glaciers are to be made.

  16. Storm surges formation in the White and Barents Seas

    Science.gov (United States)

    Arkhipkin, Victor; Dobrolyubov, Sergey; Korablina, Anastasia; Myslenkov, Stanislav

    2016-04-01

    Investigation of storm surges in the Arctic seas are of 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 safety of navigation. It is important to study the variability of surges, to predict this phenomena and subsequent economic losses, thus including such information into the Russian Arctic Development Program 2020. Surges in the White and Barents Seas are caused mainly by deep cyclones of two types: "diving" from the north (88% of all cyclones) and western. The average height of the storm surges in the White Sea is 0.6-0.9 m. An average duration of storm surges is about 80 hours. Mathematical modeling is used to analyze the characteristics of storm surges formation in the Dvina Bay of the White Sea, and in the Varandey village on the Barents Sea coast. Calculating storm surge heights in the White and Barents seas is performed using the ADCIRC model on an unstructured grid with a step from 20 km in the Barents Sea to 100 m in the White Sea. Unstructured grids allowed keeping small features of the coastline of the White and Barents seas, small islands and shallow banks, and assessing their impact on the development and transformation of wind-generated waves. The ADCIRC model used data of wind field reanalysis CFSv2. The storm surges were simulated for the time period from 1979 to 2010 and included scenarios with / without direct atmospheric pressure forcing, waves and tides. Numerical experiments have revealed distribution of storm surges in channels of the Northern Dvina River delta. The storm surges spreads in the model from the north-north-west of the Dvina Bay. As storm surge moves from the wellhead to the seaside estuary of the Northern Dvina (district Solombala), its height increases from 0.5 to 2 m. We also found a non-linear interaction of the surge and tide during the phase of surge destruction. This phenomenon is the highest in the period of low water, and the

  17. Surges Initiated by Newly-emerging Satellite Magnetic Fields

    Science.gov (United States)

    Wang, Jun-feng; Zhou, Tuan-hui; Ji, Hai-sheng

    2014-01-01

    On July 22, 2011 and in the active region NOAA 11259 there ap- peared the event of the ejection of solar atmospheric Hα surges. According to the full-disc Hα observations of the Big Bear Solar Observatory in United States, three consecutive surges at one and the same place in the north of the main spot of the active region were discovered. The trajectories of these three surges exhib- ited the figure of straight lines, and their integral configuration is like an inverted Eiffel Tower. The first two surges are quite similar, and in each of them there appeared two bright points in the northern part of the main spot. After several minutes, the surges appeared in the midst of bright points. When the bright- ness of the bright points attained the maximum value, the surges spouted out from the midst of bright points. And after reaching the maximum altitude, they quickly vanished. Before the ejection of the third surge took place, no bright points appeared. Besides, its maximal altitude is merely one half of that of the first two surges. Via a comparison with the SDO/HMI (Solar Dynamics Obser- vatory/Helioseismic and Magnetic Imager) data of radial magnetic fields, it is found that in more than one hour before the appearance of the first surge there emerged bipolar magnetic fields in the region of ejection. Besides, in several min- utes before the ejection of each Hα surge the magnetic fluxes of positive polarity diminished. Via our analysis it is found that there appeared reconnections be- tween the newly emerging satellite magnetic fields and the preexisting magnetic fields in the spot, and this caused the continuous ejections of Hα surges.

  18. 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!

  19. Concept and Features of Arrester Operating Duty Test in the Japanese Standard

    Science.gov (United States)

    Ishibe, Shinji; Ishizaki, Yoshihiro; Watanabe, Hideto; Kobayashi, Misao; Shirakawa, Shingo; Yuasa, Sadayuki; Nishimura, Seisuke

    The Japanese Electrotechnical Committee (JEC) of surge arresters has made great efforts to establish several new standards of metal-oxide surge arresters (MOSA), because the dramatic and continuous advance in the MOSA technology over the last 30 years required the new and improved test methods in succession. In the study to establish these standards, how to evaluate the MOSA performance against the energy duties has been usually the main topic because the energy duties are significantly related to the size of zinc-oxide elements and the construction of MOSA. This paper describes the concept and features of arrester operating duty tests in the JEC standards comparing with that in the standard of the International Electrotechnical Commission (IEC) and also mentions the points at issues to be studied in the future which is common to both the JEC and IEC standards. The continuous study on the improvement of the standards is required in cooperation with the activities of IEC and the Internaltional Council on Large Electric Systems (CIGRE: Conseil International des Grands Reseaux Electriques) taking into account of the latest world trend and the state-of-the-art technologies.

  20. A MICROGAP SURGE ABSORBER FABRICATED USING CONVENTIONAL SEMICONDUCTOR TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    李宏; 阮航宇

    2001-01-01

    A new type microgap surge absorber fabricated by only semiconductor technique has in it a special structure silicon chip which forms microgaps for gas discharge with electrodes, and has advantages such as small size, low cost, suitability for mass production besides the desirable characteristics that common microgap surge absorbers have. Applications of this absorber in communication facilities are discussed.

  1. Scenario-based Storm Surge Vulnerability Assessment of Catanduanes

    Science.gov (United States)

    Suarez, J. K. B.

    2015-12-01

    After the devastating storm surge effect of Typhoon Haiyan, the public recognized an improved communication about risks, vulnerabilities and what is threatened by storm surge. This can be provided by vulnerability maps which allow better visual presentations and understanding of the risks and vulnerabilities. Local implementers can direct the resources needed for protection of these areas. Moreover, vulnerability and hazard maps are relevant in all phases of disaster management designed by the National Disaster Risk Reduction Council (NDRRMC) - disaster preparedness, prevention and mitigation and response and recovery and rehabilitation. This paper aims to analyze the vulnerability of Catanduanes, a coastal province in the Philippines, to storm surges in terms of four parameters: population, built environment, natural environment and agricultural production. The vulnerability study relies on the storm surge inundation maps based on the Department of Science and Technology Nationwide Operational Assessment of Hazards' (DOST-Project NOAH) proposed four Storm Surge Advisory (SSA) scenarios (1-2, 3, 4, and 5 meters) for predicting storm surge heights. To determine total percent affected for each parameter elements, an overlay analysis was performed in ArcGIS Desktop. Moreover, vulnerability and hazard maps are generated as a final output and a tool for visualizing the impacts of storm surge event at different surge heights. The result of this study would help the selected province to know their present condition and adapt strategies to strengthen areas where they are found to be most vulnerable in order to prepare better for the future.

  2. 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

  3. Investigation of Surge Behavior in a Micro Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    Shimpei MIZUKI; Yuichiro ASAGA; Yushi ONO; Hoshio TSUJITA

    2006-01-01

    This paper reports the experimental and theoretical study of the surge occurred in prototyping an ultra micro centrifugal compressor. As the first step, the 10 times size model of an ultra micro centrifugal compressor having the 40 mm outer diameter was designed and manufactured. The detailed experimental investigations for the transient behavior of surge with several different values of B parameter were carried out. The experimental results during the surge were compared with those obtained by the non-linear lumped parameter theory in order to validate the effectiveness of the theoretical surge model for the micro centrifugal compressor. As a result, the quite different behavior of the surge appeared for the different values of B both in the experiment and in the analysis.

  4. Application of short-data methods on extreme surge levels

    Science.gov (United States)

    Feng, X.

    2014-12-01

    Tropical cyclone-induced storm surges are among the most destructive natural hazards that impact the United States. Unfortunately for academic research, the available time series for extreme surge analysis are very short. The limited data introduces uncertainty and affects the accuracy of statistical analyses of extreme surge levels. This study deals with techniques applicable to data sets less than 20 years, including simulation modelling and methods based on the parameters of the parent distribution. The verified water levels from water gauges spread along the Southwest and Southeast Florida Coast, as well as the Florida Keys, are used in this study. Methods to calculate extreme storm surges are described and reviewed, including 'classical' methods based on the generalized extreme value (GEV) distribution and the generalized Pareto distribution (GPD), and approaches designed specifically to deal with short data sets. Incorporating global-warming influence, the statistical analysis reveals enhanced extreme surge magnitudes and frequencies during warm years, while reduced levels of extreme surge activity are observed in the same study domain during cold years. Furthermore, a non-stationary GEV distribution is applied to predict the extreme surge levels with warming sea surface temperatures. The non-stationary GEV distribution indicates that with 1 Celsius degree warming in sea surface temperature from the baseline climate, the 100-year return surge level in Southwest and Southeast Florida will increase by up to 40 centimeters. The considered statistical approaches for extreme surge estimation based on short data sets will be valuable to coastal stakeholders, including urban planners, emergency managers, and the hurricane and storm surge forecasting and warning system.

  5. Problems of house arrest application

    Directory of Open Access Journals (Sweden)

    Mikhail Vladimirovich Kolesnikov

    2015-06-01

    Full Text Available Objective to determine the position of house arrest in the system of preventive measures and to identify the main problems of criminal procedural regulation that prevent its broader use during the preliminary investigation and trial. Methods dialectical approach to the analysis of social phenomena allowing to view them in static and dynamic aspect evolutionarysynergetic paradigm providing the opportunity to explore the phenomenon under investigation with respect to the system subordinate and coordinating relationships within the system. Dialectical approach and the evolutionarysynergetic paradigm determined the choice of specific methods of research historical comparative law comparative formallegal statistical. Results the problems arising with application of house arrest are grouped by author depending on the structure of the provisions of Article 107 of the CriminalProcedural Code of the Russian Federation. The first group of problems includes the determination of the location of the accused suspect under house arrest and the scope of the legal restrictions imposed. The second group includes the establishment of terms of house arrest and their subsequent renewal or change of the preventive measure. The third group is the identification of persons to which the house arrest will be the best preventive measure. The results of the study allow to make proposals to change the current wording of Art. 107 of the CriminalProcedural Code of Russia. Scientific novelty a comprehensive study of current state of the normativelegal regulation of house arrest in the context of its practical application. Practical value the main provisions and conclusions of the article can be used in scientific and pedagogical activity when considering questions about the nature of preventive measures related to the restraint of personal liberty of the accused. nbsp

  6. Analysis of Crack Arrest Toughness.

    Science.gov (United States)

    1988-01-15

    vload(m) vp tn(m) Vertical Source Load (kN) on wedge HY80 Finite Element 0.0122 0.0099 3.81x10 -4 144 Steel Calculations Experiment 0.0122 --- 3.74x10-4...curve, are bona fide measures of the fracture arrest capability of tough ductile steels . The second is that the J-values represent the crack driving...fibrous mode of crack extension. (b) A new test method for studying fast fracture and arrest in tough steels . (c) Measurements of fast fracture and crack

  7. Energy dispatching analysis of lightning surges on underground cables in a cable connection station

    Energy Technology Data Exchange (ETDEWEB)

    Hong-Chan Chang; Fu-Hsien Chen; Tai-Hsiang Chen [Department of Electrical Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei (China); Cheng-Chien Kuo [Department of Electrical Engineering, St. John' s University, 499, Sec. 4, TamKing Rd., Tamsui, Taipei (China)

    2011-01-15

    The paper aimed to simulate the transient over-voltage phenomena which occur at 345 kV and 161 kV underground cables, when lighting strikes on or near the cable connection station, by using the Electro-Magnetic Transients Program (EMTP). A feasibility study on changing related parameters, as well as cable connections and grounding methods to reduce the impact caused by lightning strikes, will be thoroughly conducted. The various components required for a detailed simulation including; lightning surges, transmission line and tower, arrester, and underground cables are all considered. Then, the transient voltage of the cables will be analyzed under different situations including; connection methods, grounding locations, length of the grounding wire of arrester, and the grounding resistance for different locations. The simulation results show that the length of the grounding wire is more sensitive to the transient over-voltage which occurred when a common grounding topology was adopted. In contrast, the use of an independent grounding topology resulted in a reduction of the grounding resistance, which effectively decreased the over-voltage, thereby avoiding surpassing the shielding voltage level of the cable, caused by the rise of ground voltage. (author)

  8. Energy dispatching analysis of lightning surges on underground cables in a cable connection station

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hong-Chan, E-mail: hcchang@mail.ntust.edu.t [Department of Electrical Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei, Taiwan (China); Chen, Fu-Hsien, E-mail: fu@mail.sju.edu.t [Department of Electrical Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei, Taiwan (China); Kuo, Cheng-Chien, E-mail: cckuo@mail.sju.edu.t [Department of Electrical Engineering, St. John' s University, 499, Sec. 4, TamKing Rd., Tamsui, Taipei, Taiwan (China); Chen, Tai-Hsiang, E-mail: thchen@yahoo.com.t [Department of Electrical Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei, Taiwan (China)

    2011-01-15

    The paper aimed to simulate the transient over-voltage phenomena which occur at 345 kV and 161 kV underground cables, when lighting strikes on or near the cable connection station, by using the Electro-Magnetic Transients Program (EMTP). A feasibility study on changing related parameters, as well as cable connections and grounding methods to reduce the impact caused by lightning strikes, will be thoroughly conducted. The various components required for a detailed simulation including; lightning surges, transmission line and tower, arrester, and underground cables are all considered. Then, the transient voltage of the cables will be analyzed under different situations including; connection methods, grounding locations, length of the grounding wire of arrester, and the grounding resistance for different locations. The simulation results show that the length of the grounding wire is more sensitive to the transient over-voltage which occurred when a common grounding topology was adopted. In contrast, the use of an independent grounding topology resulted in a reduction of the grounding resistance, which effectively decreased the over-voltage, thereby avoiding surpassing the shielding voltage level of the cable, caused by the rise of ground voltage.

  9. Risk Assessment of Hurricane Storm Surge for Tampa Bay

    Science.gov (United States)

    Lin, N.; Emanuel, K.

    2011-12-01

    Hurricane storm surge presents a major hazard for the United States and many other coastal areas around the world. Risk assessment of current and future hurricane storm surge provides the basis for risk mitigation and related decision making. This study investigates the hurricane surge risk for Tampa Bay, located on the central west coast of Florida. Although fewer storms have made landfall in the central west Florida than in regions farther west in the Gulf of Mexico and the east coast of U.S., Tampa Bay is highly vulnerable to storm surge due to its geophysical features. It is surrounded by low-lying lands, much of which may be inundated by a storm tide of 6 m. Also, edge waves trapped on the west Florida shelf can propagate along the coastline and affect the sea level outside the area of a forced storm surge; Tampa Bay may be affected by storms traversing some distance outside the Bay. Moreover, when the propagation speed of the edge wave is close to that of a storm moving parallel to the coast, resonance may occur and the water elevation in the Bay may be greatly enhanced. Therefore, Tampa Bay is vulnerable to storms with a broad spectrum of characteristics. We apply a model-based risk assessment method to carry out the investigation. To estimate the current surge risk, we apply a statistical/deterministic hurricane model to generate a set of 1500 storms for the Tampa area, under the observed current climate (represented by 1981-2000 statistics) estimated from the NCAR/NCEP reanalysis. To study the effect of climate change, we use four climate models, CNRM-CM3, ECHAM, GFDL-CM2.0, and MIROC3.2, respectively, to drive the hurricane model to generate four sets of 1500 Tampa storms under current climate conditions (represented by 1981-2000 statistics) and another four under future climate conditions of the IPCC-AR4 A1B emission scenario (represented by 2081-2100 statistics). Then, we apply two hydrodynamic models, the Advanced Circulation (ADCIRC) model and the Sea

  10. Design and construction of surge protection devices for rural distribution transformers based on the hygroscopic properties of sand

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo, Liliana; Mejia, Antonio [National University of Colombia, Bogota (Colombia). EMC Research Group], Emails: lparevalog@unal.edu.co, ajmejiau@unal.edu.co; Diaz, Oscar [Universidad Distrital FJC, Bogota (Colombia). School of Technology]. E-mail: ojdiazc@unal.edu.co

    2007-07-01

    The rural distribution transformer failure ratio due to lightning activity is a critical matter in several regions of Colombia. Different research projects have been funded by Colombian electrical companies in order to solve this problem. In some colombian regions, such as Rionegro, Cundinamarca, the transformer failure ratio has been as high as 50%. In different places around the world with a lightning activity similar to our country, the failure ratio has been kept close to 1%. The problem could be solved by developing an integral solution that includes: reduction of grounding resistance and inductive loops, specific transformer design and extensive use of surge arresters on the low and medium voltage transformer windings. The hygroscopic properties of granular materials against lightning-like current and voltage impulses were used to develop an economic surge protection device based on sand. The transformers with the highest failure ratio were selected to install this new type of surge protection device. The design and implementation of the new device for the distribution transformer low-voltage side is described in this paper. (author)

  11. Evolution of surge levels inside of the Seine Bay : interactions between tide and surge levels during Johanna and Xynthia storms

    Science.gov (United States)

    Laborie, Vanessya; Sergent, Philippe

    2015-04-01

    Within the Technical Commission for the Study and the Evaluation of Maritime Submersions in the Seine Estuary (CTeeSMES), which aim is to improve the collective knowledge on physical processes related to maritime surge levels, a numerical model of the Atlantic French Coast based on TELEMAC2D was used to study the evolution of surge levels from the ocean to the harbour area of Le Havre and evaluate the interactions between tide and surge levels in the Seine Bay. The numerical model was specifically calibrated on JOHANNA and XYNTHIA storm events, which respectively occurred in March 2008 and in February 2010. To calibrate the global signal (tide + surge levels), measurements available on 18 outputs of the Atlantic coast were used to optimize the coefficient for wind influence and for bottom friction. Maritime boundary conditions were provided by the North East Atlantic Atlas (LEGOS). Winds and pressure fields were CFSR data. Once the numerical model had been calibrated both for tide and surge levels, it has been possible to draw the evolution of surge levels from the ocean to Le Havre (quai Meunier) and then to compare the signal obtained at each point of the Seine Bay with that obtained without taking into consideration tide for each event. That also allowed to evaluate the contribution of interactions between tide and surge levels inside of the Seine Bay for Xynthia and Johanna events, but also for other events in the slice [1979-2010] and considering climate change towards 2100 with IPCC5 scenarios. It appears that instantaneous interactions between tide and surge levels nearly reach 50 % of the global surge levels and can sharply influence the evolution of surge levels in the Seine Bay depending of the moment (high tide or low water) at which the storm occurs.

  12. 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.

  13. Present dynamics and future prognosis of a slowly surging glacier

    Directory of Open Access Journals (Sweden)

    G. E. Flowers

    2010-10-01

    Full Text Available Glacier surges are a well-known example of an internal dynamic oscillation whose occurrence is not a direct response to the external climate forcing, but whose character (e.g. period, mechanism may depend on the glacier's environmental or climate setting. We examine the dynamics of a small (~5 km2 valley glacier in the Yukon Territory of Canada, where two previous surges have been photographically documented and an unusually slow surge is currently underway. To characterize the dynamics of the present surge, and to speculate on the future of this glacier, we employ a higher-order flowband model of ice dynamics with a Coulomb-friction sliding law in both diagnostic and prognostic simulations. Diagnostic (force balance calculations capture the measured ice-surface velocity profile only when high basal water pressures (55–90% of flotation are prescribed over the central region of the glacier, consistent with where evidence of the surge has been identified. This leads to sliding accounting for 50–100% of the total surface motion. Prognostic simulations, where the glacier geometry evolves in response to a prescribed surface mass balance, reveal a significant role played by a large bedrock bump beneath the current equilibrium line of the glacier. This bump provides resistance to ice flow sufficient to cause the formation of a bulge in the ice-surface profile. We suggest that the bedrock bump contributes to the propensity for surges in this glacier, such that conditions suppressing ice-bulge formation over the bump may also inhibit surges. In our calculations such a situation arises for sufficiently negative values of mass balance. Collectively, these results corroborate our interpretation of the current glacier flow regime as indicative of a "slow surge", and confirm a relationship between surge incidence or character and the net mass balance. Our results also highlight the importance of glacier bed topography in controlling ice

  14. Present dynamics and future prognosis of a slowly surging glacier

    Directory of Open Access Journals (Sweden)

    G. E. Flowers

    2011-03-01

    Full Text Available Glacier surges are a well-known example of an internal dynamic oscillation whose occurrence is not a direct response to the external climate forcing, but whose character (i.e. period, amplitude, mechanism may depend on the glacier's environmental or climate setting. We examine the dynamics of a small (∼5 km2 valley glacier in Yukon, Canada, where two previous surges have been photographically documented and an unusually slow surge is currently underway. To characterize the dynamics of the present surge, and to speculate on the future of this glacier, we employ a higher-order flowband model of ice dynamics with a regularized Coulomb-friction sliding law in both diagnostic and prognostic simulations. Diagnostic (force balance calculations capture the measured ice-surface velocity profile only when non-zero basal water pressures are prescribed over the central region of the glacier, coincident with where evidence of the surge has been identified. This leads to sliding accounting for 50–100% of the total surface motion in this region. Prognostic simulations, where the glacier geometry evolves in response to a prescribed surface mass balance, reveal a significant role played by a bedrock ridge beneath the current equilibrium line of the glacier. Ice thickening occurs above the ridge in our simulations, until the net mass balance reaches sufficiently negative values. We suggest that the bedrock ridge may contribute to the propensity for surges in this glacier by promoting the development of the reservoir area during quiescence, and may permit surges to occur under more negative balance conditions than would otherwise be possible. Collectively, these results corroborate our interpretation of the current glacier flow regime as indicative of a slow surge that has been ongoing for some time, and support a relationship between surge incidence or character and the net mass balance. Our results also highlight the importance of glacier bed

  15. Surge of the Bivachny Glacier in 2012–2015

    Directory of Open Access Journals (Sweden)

    V. M. Kotlyakov

    2015-01-01

    Full Text Available The surge of the Bivachny Glacier that occurred in 2012–2015 is analyzed with the use of photographing performed from International Space Station in 2001–2015 together with data of the satellite monitoring of 1972–2000. This surge happened in 31 years after the similar previous event of 1972–1976. Dynamics of numerous glacier branches causing activation of the lower glacier part that is so called “dead” zone (more than 7 km in length is shown. Just before its stop the front part of the surging glacier had reached the main trunk of the Fedchenko Glacier. 

  16. 14 CFR 1203b.103 - Arrest authority.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Arrest authority. 1203b.103 Section 1203b.103 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SECURITY PROGRAMS; ARREST AUTHORITY AND USE OF FORCE BY NASA SECURITY FORCE PERSONNEL § 1203b.103 Arrest authority. (a) NASA...

  17. 33 CFR 154.822 - Detonation arresters, flame arresters, and flame screens.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Detonation arresters, flame arresters, and flame screens. 154.822 Section 154.822 Navigation and Navigable Waters COAST GUARD... BULK Vapor Control Systems § 154.822 Detonation arresters, flame arresters, and flame screens. (a)...

  18. U.S. Glaucoma Cases Expected to Surge by 2030

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_162924.html U.S. Glaucoma Cases Expected to Surge by 2030 Routine ... Medicine, the National Institutes of Health, or the U.S. Department of Health and Human Services. Recent Health ...

  19. Zika-Linked Birth Defects Surge in Colombia: CDC

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_162464.html Zika-Linked Birth Defects Surge in Colombia: CDC Study ... born with devastating birth defects linked to the Zika virus is no longer confined to Brazil, a ...

  20. Storm surge model based on variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    Shi-li HUANG; Jian XU; De-guan WANG; Dong-yan LU

    2010-01-01

    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.

  1. Observations of cyclone-induced storm surge in coastal Bangladesh

    OpenAIRE

    Chiu, Soyee; Small, Christopher

    2015-01-01

    Water level measurements from 15 tide gauges in the coastal zone of Bangladesh are analyzed in conjunction with cyclone tracks and wind speed data for 54 cyclones between 1977 and 2010. Storm surge magnitude is inferred from residual water levels computed by subtracting modeled astronomical tides from observed water levels at each station. Observed residual water levels are generally smaller than reported storm surge levels for cyclones where both are available, and many cyclones produce no o...

  2. The surge-like eruption of a miniature filament

    Institute of Scientific and Technical Information of China (English)

    Jia-Yan Yang; Yun-Chun Jiang; Dan yang; Yi Bi; Bo Yang; Rui-Sheng Zheng; Jun-Chao Hong

    2012-01-01

    We report on the rare eruption of a miniature Hα filament that took the form of a surge.The filament first underwent a full development within 46 min and then began to erupt 9 min later,followed by a compact,impulsive X-ray class M2.2 flare with a two-ribbon nature only at the early eruption phase.During the eruption,its top rose,whereas the two legs remained rooted in the chromosphere and showed little swelling perpendicular to the rising direction.This led to a surge-like eruption with a narrow angular extent.Similar to the recent observations for standard and blowout X-ray jets by Moore et al.,we thus define it as a "blowout Hα surge." Furthermore,our observations showed that the eruption was associated with (1) a coronal mass ejection guided by a pre-existing streamer,(2) abrupt,significant,and persistent changes in the photospheric magnetic field around the filament,and (3) a sudden disappearance of a small pore.These observations thus provide evidence that a blowout surge is a small-scale version of a large-scale filament eruption in many aspects.Our observations further suggest that at least part of the Hα surges belong to blowout-type cases,and the exact distinction between the standard and blowout Hα surges is important in understanding their different origins and associated eruptive phenomena.

  3. 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.

  4. The role of mangroves in attenuating storm surges

    Science.gov (United States)

    Zhang, Keqi; Liu, Huiqing; Li, Yuepeng; Xu, Hongzhou; Shen, Jian; Rhome, Jamie; Smith, J.

    2012-01-01

    Field observations and numerical simulations indicate that the 6-to-30-km-wide mangrove forest along the Gulf Coast of South Florida effectively attenuated stormsurges from a Category 3 hurricane, Wilma, and protected the inland wetland by reducing an inundation area of 1800 km2 and restricting surge inundation inside the mangrove zone. The surge amplitude decreases at a rate of 40–50 cm/km across the mangrove forest and at a rate of 20 cm/km across the areas with a mixture of mangrove islands with open water. In contrast, the amplitudes of stormsurges at the front of the mangrove zone increase by about 10–30% because of the "blockage" of mangroves to surge water, which can cause greater impacts on structures at the front of mangroves than the case without mangroves. The mangrove forest can also protect the wetlands behind the mangrove zone against surge inundation from a Category 5 hurricane with a fast forward speed of 11.2 m/s (25 mph). However, the forest cannot fully attenuate stormsurges from a Category 5 hurricane with a slow forward speed of 2.2 m/s (5 mph) and reduced surges can still affect the wetlands behind the mangrove zone. The effects of widths of mangrove zones on reducing surge amplitudes are nonlinear with large reduction rates (15–30%) for initial width increments and small rates (<5%) for subsequent width increments.

  5. Requirement of ultra-high voltage GIS arrester to voltage gradient of metal-oxide varistor

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The surge arrester with excellent protection characteristics would decrease the overvoltage level ap- plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The arrester for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite element method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the resulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrester would be controlled smaller than 10%. The result in this paper provides the fundamental technical index for the study of the high voltage gradient ZnO varistors.

  6. Neurologic management following cardiac arrest.

    Science.gov (United States)

    Bircher, N G

    1989-10-01

    Optimal neurologic outcome after cardiac arrest requires careful attention to the details of both intracranial and extracranial homeostasis. A high index of suspicion regarding the potential causes and complications of cardiac arrest facilitates discovery and treatment of problems before they adversely affect neurologic outcome. The future is bright for resuscitation research: Our fundamental understanding of cerebral ischemia and its consequences has dramatically improved, and this knowledge can hopefully be transferred to clinical useful modes of therapy. However, the transition from a promising, therapeutically effective intervention in animals to the demonstration that treatment is effective following cardiac arrest in humans is an important and difficult step. The patient population is heterogeneous before the insult, the duration and severity of the insult are variable, and the effectiveness of cardiopulmonary resuscitation varies among institutions. Therefore, the only means of demonstrating clinical efficacy is the performance of a large clinical trial. The Resuscitation Research Center at the University of Pittsburgh has developed and coordinated a multicenter, multinational team of investigators who have completed one definitive trial of postarrest barbiturate therapy and are currently completing a similar trial using a calcium entry blocker. Despite the formidable obstacles posed by such comprehensive efforts, they provide the mechanism for determining whether the cost of a new treatment modality is justified by the likelihood of improved mortality or morbidity.

  7. Improved PV system reliability results from surge evaluations at Sandia National Laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Russell H. Bonn; Sigifredo Gonzalez

    2000-04-11

    Electrical surges on ac and dc inverter power wiring and diagnostic cables have the potential to shorten the lifetime of power electronics. These surges may be caused by either nearby lightning or capacitor switching transients. This paper contains a description of ongoing surge evaluations of PV power electronics and surge mitigation hardware at Sandia.

  8. Surge-type glaciers in the Tien Shan (Central Asia)

    Science.gov (United States)

    Mukherjee, Kriti; Bolch, Tobias

    2016-04-01

    Surge-type glaciers in High Mountain Asia are mostly observed in Karakoram and Pamir. However, few surge-type glaciers also exist in the Tien Shan, but have not comprehensively studied in detail in the recent literature. We identified surge-type glaciers in the Tien Shan either from available literature or by manual interpretation using available satellite images (such as Corona, Hexagon, Landsat, SPOT, IRS) for the period 1960 to 2014. We identified 39 possible surge-type glaciers, showing typical characteristics like looped moraines. Twenty-two of them rapidly advanced during different periods or a surge was clearly described in the literature. For the remaining possible surge-type glaciers either the advance, in terms of time and length, were not mentioned in detail in the literature, or the glaciers have remained either stable or retreated during the entire period of our study. Most of the surge-type glaciers cluster in the Inner Tien Shan (especially in the Ak-Shiirak rage) and the Central Tien Shan, are in size and are facing North, West or North West. Pronounced surge events were observed for North Inylchek and Samoilowitsch glaciers, both of which are located in the Central Tien Shan. Samoilowitsch Glacier retreated by more than 3 km between 1960 (length ~8.9 km) and 1992 (~5.8 km), advanced by almost 3 km until 2006 and slightly retreated thereafter. The most pronounced advance occurred between 2000 and 2002. DEM differencing (based on SRTM3 data and stereo Hexagon and Cartosat-1 data) revealed a significant thickening in the middle reaches (reservoir area) of the glacier between 1973 and 2000 while the surface significantly lowered in the middle and upper parts of the glacier between 2000 and 2006. Hence, the ice mass was transferred to the lower reaches (receiving area) and caused the advance with a maximum thickening of more than 80 m. The ~30 km long North Inylchek Glacier retreated since 1943 and showed a very rapid advance of ~3.5 km especially in

  9. The influence of climate during and after a glacial surge - A comparison of the last two surges of Fridtjovbreen, Svalbard

    Science.gov (United States)

    Lønne, Ida

    2014-02-01

    Glacial surges are periods of fast flow, often limited in space and time, and driven by internal conditions which are not fully explained. The quantity and variety of documented case-studies and settings demonstrate that the critical variables are difficult to isolate. In an alternative approach, two surges from the same basin were compared at Fridtjovhamna; one of the few known sites where this is possible. Fridtjovbreen is a polythermal glacier that has been through two recent surges: the last event (1991-2002) occurred during an unusually warm period in the high Arctic, whereas the previous surge culminated in 1861, around the Little Ice Age when many Svalbard-glaciers had their maximum Holocene extent. Based on a multi-disciplinary study, processes and landforms from the two episodes were compared with respect to ice-front movement rates, formation and decay of ice-cored moraines and glacial meltwater drainage patterns. The study demonstrates that moraines and meltwater traces from the oldest surge, locally well preserved, provide excellent opportunities for reconstructing the behavior of the ice-mass. The last surge, however, took place during a period with ablation rates never seen at this latitude, and 10 years after the maximum extent, the deglaciated areas onshore hardly show traces from the event.

  10. A High Density Storm Surge Monitoring Network: Evaluating the Ability of Wetland Vegetation to Reduce Storm Surge

    Science.gov (United States)

    Lawler, S.; Denton, M.; Ferreira, C.

    2013-12-01

    Recent tropical storm activity in the Chesapeake Bay and a potential increase in the predicted frequency and magnitude of weather systems have drawn increased attention to the need for improved tools for monitoring, modeling and predicting the magnitude of storm surge, coastal flooding and the respective damage to infrastructure and wetland ecosystems. Among other forms of flood protection, it is believed that coastal wetlands and vegetation can act as a natural barrier that slows hurricane flooding, helping to reduce the impact of storm surge. However, quantifying the relationship between the physical process of storm surge and its attenuation by wetland vegetation is an active area of research and the deployment of in-situ measuring devices is crucial to data collection efforts in this field. The United States Geological Survey (USGS) mobile storm-surge network has already successfully provided a framework for evaluating hurricane induced storm surge water levels on a regional scale through the use of in-situ devices installed in areas affected by storm surge during extreme events. Based on the success of the USGS efforts, in this study we adapted the monitoring network to cover relatively small areas of wetlands and coastal vegetation with an increased density of sensors. Groups of 6 to 10 water level sensors were installed in sites strategically selected in three locations on the Virginia coast of the lower Chesapeake Bay area to monitor different types of vegetation and the resulting hydrodynamic patterns (open coast and inland waters). Each group of sensors recorded time series data of water levels for both astronomical tide circulation and meteorological induced surge. Field campaigns were carried out to survey characteristics of vegetation contributing to flow resistance (i.e. height, diameter and stem density) and mapped using high precision GPS. A geodatabase containing data from field campaigns will support the development and calibration of

  11. 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)

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

    Science.gov (United States)

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

    2009-05-01

    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 2 weeks before and 2 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 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.

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

    Directory of Open Access Journals (Sweden)

    M. Braun

    2012-03-01

    Full Text Available A 2008–2011 surge of Bering Glacier, Alaska is examined using observations of surface velocity and surface elevation change. Velocity measurements are obtained using synthetic aperture radar (SAR offset tracking and elevation data are obtained from the University of Alaska Fairbanks LiDAR altimetry program. Bering Glacier began to surge in May 2008 and had two phases of accelerated flow. The first phase accelerated progressively for at least 10 months and reached peak observed velocities of ~7 m d−1. Results suggest that during the quiescent phase, prior to the surge, periods of accelerated flow increased driving stresses up to 70% in a ~10 km-long section of the Lower Bering. When the first phase of the surge initiated, synchronous acceleration occurred throughout much of the glacier length, indicating widespread pressurization of the bed, but the largest accelerations initiated at the location where driving stress built up during quiescence. From there, rapid flow velocities propagated upstream and downstream across much of the glacier length and transpired as small, transient and unorganized propagation fronts. The second phase occurred in 2011 and was of comparable scale to the surge in 1993–1995, with velocities exceeding 9 m d−1 or ~18 times quiescent velocities.

  14. Cognitive impairment after sudden cardiac arrest

    OpenAIRE

    Jaszke-Psonka, Magdalena; Piegza, Magdalena; Ścisło, Piotr; Pudlo, Robert; Piegza, Jacek; Badura-Brzoza, Karina; Leksowska, Aleksandra; Hese, Robert T.; Gorczyca, Piotr W.

    2016-01-01

    Aim To evaluate the incidence and severity of the impairment of selected cognitive functions in patients after sudden cardiac arrest (SCA) in comparison to patients after myocardial infarction without SCA and healthy subjects and to analyze the influence of sociodemographic and clinical parameters and the duration of cardiac arrest on the presence and severity of the described disorders. Material and methods The study group comprised 30 cardiac arrest survivors, the reference group comprised ...

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

    Directory of Open Access Journals (Sweden)

    G. MUNGOV

    2012-12-01

    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.

  16. Observations of cyclone-induced storm surge in coastal Bangladesh

    CERN Document Server

    Chiu, Soyee

    2015-01-01

    Water level measurements from 15 tide gauges in the coastal zone of Bangladesh are analyzed in conjunction with cyclone tracks and wind speed data for 54 cyclones between 1977 and 2010. Storm surge magnitude is inferred from residual water levels computed by subtracting modeled astronomical tides from observed water levels at each station. Observed residual water levels are generally smaller than reported storm surge levels for cyclones where both are available, and many cyclones produce no obvious residual at all. Both maximum and minimum residual water levels are higher for west-landing cyclones producing onshore winds and generally diminish for cyclones making landfall on the Bangladesh coast or eastward producing offshore winds. Water levels observed during cyclones are generally more strongly influenced by tidal phase and amplitude than by storm surge alone. In only 7 of the 15 stations does the highest plausible observed water level coincide with a cyclone. While cyclone-coincident residual water level ...

  17. A numerical storm surge forecast model with Kalman filter

    Institute of Scientific and Technical Information of China (English)

    Yu Fujiang; Zhang Zhanhai; Lin Yihua

    2001-01-01

    Kalman filter data assimilation technique is incorporated into a standard two-dimensional linear storm surge model. Imperfect model equation and imperfect meteorological forcimg are accounted for by adding noise terms to the momentum equations. The deterministic model output is corrected by using the available tidal gauge station data. The stationary Kalman filter algorithm for the model domain is calculated by an iterative procedure using specified information on the inaccuracies in the momentum equations and specified error information for the observations. An application to a real storm surge that occurred in the summer of 1956 in the East China Sea is performed by means of this data assimilation technique. The result shows that Kalman filter is useful for storm surge forecast and hindcast.

  18. 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...

  19. Arresting relaxation in Pickering Emulsions

    Science.gov (United States)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  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. Wave-Tide-Surge Coupled Simulation for Typhoon Maemi

    Institute of Scientific and Technical Information of China (English)

    Byung Ho Choi; Byung Il Min; Kyeong Ok Kim; Jin Hee Yuk

    2013-01-01

    The main task of this study focuses on studying the effect of wave-current interaction on currents,storm surge and wind wave as well as effects of current induced wave refraction and current on waves by using numerical models which consider the bottom boundary layer and sea surface roughness parameter for shallow and smooth bed area around Korean Peninsula.The coupled system (unstructured-mesh SWAN wave and ADCIRC) run on the same unstructured mesh.This identical and homogeneous mesh allows the physics of wave-circulation interactions to be correctly resolved in both models.The unstructured mesh can be applied to a large domain allowing all energy from deep to shallow waters to be seamlessly followed.There is no nesting or overlapping of structured wave meshes,and no interpolation is required.In response to typhoon Maemi (2003),all model components were validated independently,and shown to provide a faithful representation of the system's response to this storm.The waves and storm surge were allowed to develop on the continental shelf and interact with the complex nearshore environment.The resulting modeling system can be used extensively for prediction of the typhoon surge.The result show that it is important to incorporate the wave-current interaction effect into coastal area in the wave-tide-surge coupled model.At the same time,it should consider effects of depth-induced wave breaking,wind field,currents and sea surface elevation in prediction of waves.Specially,we found that:(1) wave radiation stress enhanced the current and surge elevation otherwise wave enhanced nonlinear bottom boundary layer decreased that,(2) wind wave was significantly controlled by sea surface roughness thus we cautiously took the experimental expression.The resulting modeling system can be used for hindcasting (prediction) the wave-tide-surge coupled environments at complex coastline,shallow water and fine sediment area like areas around Korean Peninsula.

  2. 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...... 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 the surge of network-driven innovation. Network-driven innovation is unfolded on top of the known cost- driven...

  3. 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.

  4. A High Resolution Forecast Model of Storm Surge Inundation

    Institute of Scientific and Technical Information of China (English)

    LIU Juan; JIANG Wensheng; SUN Wenxin; WANG Yongzhi

    2005-01-01

    In order to forecast storm surge inundation, a two-dimensional model is established. In the model, an alternating computation sequence method is used to solve the governing equations, and the dry and wet method is introduced to treat the moving boundary. This model is easy to use. It has a friendly input interface and Arcview GIS is used as the output interface. The model is applied to the Shantou area to simulate the storm surge elevations and inundations caused by Typhoons 6903 ane 0104 using the same relevant parameters. The calculated results agree well with the observations.

  5. Surge of the Bivachny Glacier in 2012–2015

    OpenAIRE

    V. M. Kotlyakov; L. V. Desinov; V. A. Rudakov

    2015-01-01

    The surge of the Bivachny Glacier that occurred in 2012–2015 is analyzed with the use of photographing performed from International Space Station in 2001–2015 together with data of the satellite monitoring of 1972–2000. This surge happened in 31 years after the similar previous event of 1972–1976. Dynamics of numerous glacier branches causing activation of the lower glacier part that is so called “dead” zone (more than 7 km in length) is shown. Just before its stop the front part of the surgi...

  6. Geological Controls on Glacier Surging?: Statistics and Speculation

    Science.gov (United States)

    Flowers, G. E.; Crompton, J. W.

    2015-12-01

    Glacier surging represents an end-member behavior in the spectrum of ice dynamics, involving marked acceleration and high flow speeds due to abrupt changes in basal mechanics. Though much effort has been devoted to understanding the role of basal hydrology and thermal regime in fast glacier flow, fewer studies have addressed the potential role of the geologic substrate. One interesting observation is that surge-type glaciers appear almost universally associated with unconsolidated (till) beds, and several large-scale statistical studies have revealed correlations between glacier surging and bedrock properties. We revisit this relationship using field measurements. We selected 20 individual glaciers for sampling in a 40x40 km region of the St. Elias Mountains of Yukon, Canada. Eleven of these glaciers are known to surge and nine are not. The 20 study glaciers are underlain by lithologies that we have broadly classified into two types: metasedimentary only and mixed metasedimentary-granodiorite. We characterized geological and geotechnical properties of the bedrock in each basin, and analyzed the hydrochemistry and mineralogy and grain size distribution (GSD) of the suspended sediments in the proglacial streams. Here we focus on some intriguing results of the GSD analysis. Using statistical techniques, including significance testing and principal component analysis, we find that: (1) lithology determines GSD for non-surge-type glaciers, with metasedimentary basins associated with finer mean grain sizes and mixed-lithology basins with coarser mean grain sizes, but (2) the GSDs associated with surge-type glaciers are intermediate between the distributions described above, and are statistically indistinguishable between metasedimentary and mixed lithology basins. The latter suggests either that surge-type glaciers in our study area occur preferentially in basins where various processes conspire to produce a characteristic GSD, or that the surge cycle itself exerts an

  7. Metal Oxide Surge Arresters Line Monitoring%金属氧化物避雷器的在线监测

    Institute of Scientific and Technical Information of China (English)

    苏红艳

    2009-01-01

    氧化物避雷器泄漏电流的关键测试是阻性电流测量,无论是设备交接验收还是预防性试验都不能缺少.当前现场使用较为广泛的测量阻性电流的方法是电容补偿法.主要介绍了其测量原理、测量方法、注意事项.

  8. Application of Metal Oxide Surge Arrester on the Non-Conventional Chaotic Ferroresonance Oscillation in Voltage Transformers

    Directory of Open Access Journals (Sweden)

    Hamid Radmanesh

    2012-09-01

    Full Text Available In this study the effect of MOSA on controlling of the non-conventional ferroresonance overvoltage in the iron core voltage transformer is studied. It is expected that MOSA can generally damp ferroresonance overvoltages. Time-domain study is used to analyze this effect. Study is done on a voltage transformer rated 100VA, 275 kV. The magnetization characteristic of the transformer coil is modeled by a single-parameter twoterm polynomial with q = 7 degree of nonlinearity. Core loss is modeled by linear resistance. Simulation results show that connecting the MOSA in parallel to the voltage transformer, shows a great controlling effect of the ferroresonance oscillations. Phase plane, time domain voltage waveforms, FFT analysis and bifurcation diagrams are also given. Significant effect on settling down to the chaos, the range of parameter values that may lead to ferroresonance overvoltages and controlling these phenomena are obtained and presented.

  9. NUMERICAL STUDY OF THE INFLUENCE OF WAVES AND TIDE-SURGE INTERACTION ON TIDE-SURGES IN THE BOHAI SEA

    Institute of Scientific and Technical Information of China (English)

    尹宝树; 侯一筠; 程明华; 苏京志; 林明祥; 李明悝; M.I.El-Sabh

    2001-01-01

    Abstract The author's combined numerical model consisting of a third generation shallow water wave model and a 3-D tide-surge model with wave-dependent surface wind stress were used to study the influence of waves on fide-surge motion. For the typical weather case, in this study, the magnitude and mechanism of the influence of waves on tide-surges in the Bohai Sea were revealed for the first time. The results showed that although consideration of the wave-dependent surface wind stresses raise slightly the traditional surface wind stress, due to the accumulated effects, the computed results are improved on the whole. Storm level maximum modulation can reach 0.4 m. The results computed by the combined model agreed well with the measured data.

  10. NUMERICAL STUDY OF THE INFLUENCE OF WAVES AND TIDE- SURGE INTERACTION ON TIDE-SURGES IN THE BOHAI SEA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The author's combined numerical model consisting of a third generation shallow water wave model and a 3-D tide-surge model with wave-dependent surface wind stress were used to study the influence of waves on tide-surge motion. For the typical weather case, in this study, the magnitude and mechanism of the influence of waves on tide-surges in the Bohai Sea were revealed for the first time. The results showed that although consideration of the wave-dependent surface wind stresses raise slightly the traditional surface wind stress, due to the accumulated effects, the computed results are improved on the whole. Storm level maximum modulation can reach 0.4 m. The results computed by the combined model agreed well with the measured data.

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

    African Journals Online (AJOL)

    dell

    ... cardiac arrest occurred in 5 cases (4.6%) with successful resuscitation in 2 .... patients needed immediate preoperative ICU admission for cardiopulmonary ... Most of the affected children are usually below 3 years of age and this is in ...

  12. Psychopathology in Women Arrested for Domestic Violence

    Science.gov (United States)

    Stuart, Gregory L.; Moore, Todd M.; Gordon, Kristina Coop; Ramsey, Susan E.; Kahler, Christopher W.

    2006-01-01

    This study examined the prevalence of psychopathology among women arrested for violence and whether the experience of intimate partner violence (IPV) was associated with Axis I psychopathology. Women who were arrested for domestic violence perpetration and court referred to violence intervention programs (N=103) completed measures of IPV…

  13. Arrested segregative phase separation in capillary tubes

    NARCIS (Netherlands)

    Tromp, R. Hans; Lindhoud, Saskia

    2006-01-01

    Phase separation in a capillary tube with one of the phases fully wetting the capillary wall is arrested when the typical size of the phase domains reaches the value of the diameter of the tube. The arrested state consists of an alternating sequence of concave-capped and convex-capped cylindrical

  14. Physeal arrest of the distal radius.

    Science.gov (United States)

    Abzug, Joshua M; Little, Kevin; Kozin, Scott H

    2014-06-01

    Fractures of the distal radius are among the most common pediatric fractures. Although most of these fractures heal without complication, some result in partial or complete physeal arrest. The risk of physeal arrest can be reduced by avoiding known risk factors during fracture management, including multiple attempts at fracture reduction. Athletes may place substantial compressive and shear forces across the distal radial physes, making them prone to growth arrest. Timely recognition of physeal arrest can allow for more predictable procedures to be performed, such as distal ulnar epiphysiodesis. In cases of partial arrest, physeal bar excision with interposition grafting can be performed. Once ulnar abutment is present, more invasive procedures may be required, including ulnar shortening osteotomy or radial lengthening.

  15. Why Teen Mental Ability Surges While Brain Shrinks

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_166310.html Why Teen Mental Ability Surges While Brain Shrinks Researchers say they may have answer to ... behavior keep scaling up," he said. So while teens lose brain volume and girls have lower brain volume than ...

  16. 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...

  17. Monitoring Inland Storm Surge and Flooding from Hurricane Rita

    Science.gov (United States)

    McGee, Benton D.; Tollett, Roland W.; Mason, Jr., Robert R.

    2006-01-01

    Pressure transducers (sensors) and high-water marks were used to document the inland water levels related to storm surge generated by Hurricane Rita in southwestern Louisiana and southeastern Texas. On September 22-23, 2005, an experimental monitoring network of sensors was deployed at 33 sites over an area of about 4,000 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding. Sensors were programmed to record date and time, temperature, and barometric or water pressure. Water pressure was corrected for changes in barometric pressure and salinity. Elevation surveys using global-positioning systems and differential levels were used to relate all storm-surge water-level data, reference marks, benchmarks, sensor measuring points, and high-water marks to the North American Vertical Datum of 1988 (NAVD 88). The resulting data indicated that storm-surge water levels over 14 feet above NAVD 88 occurred at three locations, and rates of water-level rise greater than 5 feet per hour occurred at three locations near the Louisiana coast.

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

    African Journals Online (AJOL)

    Hp 630 Dual Core

    COSECSA/ASEA Publication - East and Central African Journal of Surgery. December 2016; Vol. .... shorter duration (median of 20 weeks vs. 3.5 weeks, p 0.029). .... inguinal hernia in children: laparoscopic or open? Eur J Ped Surg 2011; 21: ...

  19. Debris entrainment and landform genesis during tidewater glacier surges

    Science.gov (United States)

    Lovell, Harold; Fleming, Edward J.; Benn, Douglas I.; Hubbard, Bryn; Lukas, Sven; Rea, Brice R.; Noormets, Riko; Flink, Anne E.

    2015-08-01

    The englacial entrainment of basal debris during surges presents an opportunity to investigate processes acting at the glacier bed. The subsequent melt-out of debris-rich englacial structures during the quiescent phase produces geometrical ridge networks on glacier forelands that are diagnostic of surge activity. We investigate the link between debris entrainment and proglacial geomorphology by analyzing basal ice, englacial structures, and ridge networks exposed at the margins of Tunabreen, a tidewater surge-type glacier in Svalbard. The basal ice facies display clear evidence for brittle and ductile tectonic deformation, resulting in overall thickening of the basal ice sequence. The formation of debris-poor dispersed facies ice is the result of strain-induced metamorphism of meteoric ice near the bed. Debris-rich englacial structures display a variety of characteristics and morphologies and are interpreted to represent the incorporation and elevation of subglacial till via the squeezing of till into basal crevasses and hydrofracture exploitation of thrust faults, reoriented crevasse squeezes, and preexisting fractures. These structures are observed to melt-out and form embryonic geometrical ridge networks at the base of a terrestrially grounded ice cliff. Ridge networks are also located at the terrestrial margins of Tunabreen, neighboring Von Postbreen, and in a submarine position within Tempelfjorden. Analysis of network characteristics allows these ridges to be linked to different formational mechanisms of their parent debris-rich englacial structures. This in turn provides an insight into variations in the dominant tectonic stress regimes acting across the glacier during surges.

  20. 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...

  1. A basis function approach for exploring the seasonal and spatial features of storm surge events

    Science.gov (United States)

    Wu, Wenyan; Westra, Seth; Leonard, Michael

    2017-07-01

    Storm surge is a significant contributor to flooding in coastal and estuarine regions. To represent the statistical characteristics of storm surge over a climatologically diverse region, we propose the use of basis functions that capture the temporal progression of individual storm surge events. This extends statistical analyses of surge from considering only the peak to a more multifaceted approach that also includes decay rate and duration. Our results show that there is seasonal variation in storm surge along the Australian coastline. During the dominant storm surge seasons, the peak and duration of storm surge events tend to increase simultaneously at a number of locations, with implications for flood damage assessments and evacuation planning. By combining the dynamic and statistical features of storm surge, it is possible to better understand the factors that can lead to flood risk along the coastline, including estuarine areas that are also affected by fluvial floods.

  2. 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.

    India and its neighbourhood is threatened by the possibility of storm surge floods whenever a tropical cyclone approaches. Storm surge disasters cause heavy loss of life and property, damage to the coastal structures and agriculture nwhich lead...

  3. 模块式SPD电涌保护器制作构造探讨%To Explore the Structure of Modular SPD Surge Protection Device Fabrication

    Institute of Scientific and Technical Information of China (English)

    马立

    2015-01-01

    The module type SPD surge protection device performance,production and installation status are reviewed. Elaborated various problems of modular SPD surge protector in practical application caused by installation position,direction and wiring. Though the analysis of the construction of the modular power supply lightning arrester,provided technical guidance and support for the installation of modular SPD surge protection device in practical application.%对模块式SPD电涌保护器的性能、制作和安装现状进行综合评述,详细阐述模块式SPD电涌保护器在实际应用中因安装位置、方向和接线布线引起的各种问题。通过对现常用的模块式电源防雷器的制作构造进行分析,为模块式SPD电涌保护器在实际应用中的安装提供技术指导和支持。

  4. Effect of Coupling Wave and Flow Dynamics on Hurricane Surge and Inundation

    Science.gov (United States)

    2012-01-01

    impacted hurricanes - both by the wind fields as well as by the accompanying surge. Forecasting the extent of the inundation is critical for local...estimate local surge hazards; and in the other, ensemble model runs are used to determine surge values from a set of parameterized storms [Irish et...with the storm surge to create the storm tide. The extent of coastal inundation - flooding of inland surface that is not normally submerged, is

  5. Brief Communication: On the magnitude and frequency of Khurdopin glacier surge events

    OpenAIRE

    D. J. Quincey; Luckman, A.

    2014-01-01

    The return periods of Karakoram glacier surges are poorly quantified. Here, we present evidence of an historic surge of the Khurdopin Glacier that began in the mid-1970s and peaked in 1979. Measured surface displacements reached >5 km a−1, two orders of magnitude faster than during quiescence. The Khurdopin Glacier next surged in the late 1990s, equating to a return period of 20 years. Surge evolution in the two events shows remarkable similarity suggesting a common trigger....

  6. Chromosomal Aneuploidies and Early Embryonic Developmental Arrest

    Directory of Open Access Journals (Sweden)

    Maria Maurer

    2015-07-01

    Full Text Available Background: Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. Materials and Methods: This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Results: Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Conclusion: Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting.

  7. [Cardiopulmonary resuscitation in cardiac arrest following trauma].

    Science.gov (United States)

    Leidel, B A; Kanz, K-G

    2016-11-01

    For decades, survival rates of cardiac arrest following trauma were reported between 0 and 2 %. Since 2005, survival rates have increased with a wide range up to 39 % and good neurological recovery in every second person injured for unknown reasons. Especially in children, high survival rates with good neurologic outcomes are published. Resuscitation following traumatic cardiac arrest differs significantly from nontraumatic causes. Paramount is treatment of reversible causes, which include massive bleeding, hypoxia, tension pneumothorax, and pericardial tamponade. Treatment of reversible causes should be simultaneous. Chest compression is inferior following traumatic cardiac arrest and should never delay treatment of reversible causes of the traumatic cardiac arrest. In massive bleeding, bleeding control has priority. Damage control resuscitation with permissive hypotension, aggressive coagulation therapy, and damage control surgery represent the pillars of initial treatment. Cardiac arrest due to hypoxia should be resolved by airway management and ventilation. Tension pneumothorax should be decompressed by finger thoracostomy, pericardial tamponade by resuscitative thoracotomy. In addition, resuscitative thoracotomy allows direct and indirect bleeding control. Untreated impact brain apnea may rapidly lead to cardiac arrest and requires quick opening of the airway and effective oxygenation. Established algorithms for treatment of cardiac arrest following trauma enable a safe, structured, and effective management.

  8. Theory of dynamic arrest in colloidal mixtures.

    Science.gov (United States)

    Juárez-Maldonado, R; Medina-Noyola, M

    2008-05-01

    We present a first-principles theory of dynamic arrest in colloidal mixtures based on the multicomponent self-consistent generalized Langevin equation theory of colloid dynamics [M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E 72, 031107 (2005); M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E76, 039902 (2007)]. We illustrate its application with a description of dynamic arrest in two simple model colloidal mixtures: namely, hard-sphere and repulsive Yukawa binary mixtures. Our results include observation of the two patterns of dynamic arrest, one in which both species become simultaneously arrested and the other involving the sequential arrest of the two species. The latter case gives rise to mixed states in which one species is arrested while the other species remains mobile. We also derive the ("bifurcation" or fixed-point") equations for the nonergodic parameters of the system, which takes the surprisingly simple form of a system of coupled equations for the localization length of the particles of each species. The solution of this system of equations indicates unambiguously which species is arrested (finite localization length) and which species remains ergodic (infinite localization length). As a result, we are able to draw the entire ergodic-nonergodic phase diagram of the binary hard-sphere mixture.

  9. 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,...

  10. 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...

  11. THE STUDY OF ALLOCATION OF SURGE BUNKER IN MINE HAULAGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    王喜富; 张幼蒂; 张达贤

    1997-01-01

    Based on the function analysis of surge bunker in mine haulage system, the authors raise the calculation methods of the total output of a mine haulage system. Taking the maximum of system's total throughput as a objective, the method of determining the surge bunker's rational size is put forward. Also, the problems of rational position of surge bunker are analysesed.

  12. A model study of Abrahamsenbreen, a surging glacier in northern Spitsbergen

    NARCIS (Netherlands)

    Oerlemans, J.; van Pelt, W. J. J.

    2015-01-01

    The climate sensitivity of Abrahamsenbreen, a 20 km long surge-type glacier in northern Spitsbergen, is studied with a simple glacier model. A scheme to describe the surges is included, which makes it possible to account for the effect of surges on the total mass budget of the glacier. A climate rec

  13. Cardiac Arrest: Obstetric CPR/ACLS.

    Science.gov (United States)

    Cobb, Benjamin; Lipman, Steven

    2017-01-10

    In contrast with other high-resource countries, maternal mortality has seen an increase in the United States. Caring for pregnant women in cardiac arrest may prove uniquely challenging given the rarity of the event coupled by the physiological changes of pregnancy. Optimization of resuscitative efforts warrants special attention as described in the 2015 American Heart Association's "Scientific Statement on Maternal Cardiac Arrest." Current recommendations address a variety of topics ranging from the basic components of chest compressions and airway management to some of the logistical complexities and operational challenges involved in maternal cardiac arrest.

  14. Building and Analyzing SURGEDAT: The World's Most Comprehensive Storm Surge Database

    Science.gov (United States)

    Needham, H.; Keim, B.

    2012-12-01

    SURGEDAT, the world's most comprehensive tropical storm surge database, has identified and mapped the location and height of hundreds of global storm surge events. This project originated with a study that identified more than 200 tropical surge events along the U.S. Gulf Coast. Spatial analysis of these data reveal that the central and western Gulf Coast observe more frequent and higher magnitude surges, whereas much of the eastern Gulf Coast, including the west coast of Florida, experiences less storm surge activity. Basin-wide return period analysis of these data estimate a 100-year return period of 8.20m, and a 10-year return period of 4.95m. Return period analysis of 10 sub-regions within the basin reveal that the highest surge levels occur in the Southeast Louisiana/ Mississippi zone, which includes the New Orleans metropolitan area. The 100-year surge level in this zone is estimated to be 7.67m. The Southeast Texas/ Southwest Louisiana zone, which includes the Houston metropolitan area, has the second highest surge levels, with a 100-year storm surge estimate of 6.30m. Surge levels are lower on the west coast of Florida, where the 100-year surge level is estimated between three and four meters. Expansion of this work includes mapping all high water marks for each surge event and the creation of a search-by-location web tool, which enables users to see the entire storm surge history for specific locations. In addition, the dataset has expanded internationally and now includes more than 500 surge events, as surges have now been identified in all the major ocean basins that experience tropical cyclones. International partnerships are sought to further expand this work, particularly in Australia, China, Japan, Philippines, India, Bangladesh, Myanmar, Mexico and various countries in Oceania and the Caribbean.; ;

  15. Waves of accelerated motion in a glacier approaching surge: the mini-surges of Variegated Glacier, Alaska, U.S.A.

    OpenAIRE

    Kamb, Barclay; Engelhardt, Hermann

    1987-01-01

    Periods of dramatically accelerated motion, in which the flow velocity increases suddenly from about 55 cm/d to a peak of 100-300 cm/d and then decreases gradually over the course of a day, occurred repeatedly during June and July 1978-81 in Variegated Glacier (Alaska), a surging-type glacier that surged in 1982-83. These "mini-surges" appear to be related mechanistically to the main surge. The flow-velocity peak propagates down-glacier as a wave at a speed of about 0.3 km/h, over a reach of ...

  16. Analysis on Lightning Surge Propagation in Wind Farm

    Science.gov (United States)

    Yasuda, Yoh; Hara, Takehisa; Funabashi, Toshihisa

    Wind power generation is expected to become more important in the future distribution system. Although several prospective reports such as IEC 61400-24 and NREL SR-500-31115 indicate on insulation scheme and grounding design for lightning protection, it still seems that there are not many investigations on the problems. This paper therefore discusses lightning surge analysis using wind farm model with 2 or 10 ideal wind turbines. Changing parameters such as grounding resistance and lightning strike points, several cases were studied. As the result of the analysis using digital simulator ARENE, it is clear that the surge tends to propagate toward the end of a distribution line in a wind farm and there is possibility of insulation accidents at the other wind turbines when lightning attacks a wind turbine.

  17. RESEARCH ON THE CONDITION TO SET A TAILRACE SURGE TANK

    Institute of Scientific and Technical Information of China (English)

    ZHAO Gui-lian; YANG jian-dong; XU Yuan-jie; LI Jin-ping

    2004-01-01

    When using the draft-tube vacuum to be less than 8.0m as the rule to set a tailrace surge tank, a mixing function that describes the process of water-hammer vacuum and velocity-head vacuum varied with time is proposed, on the assumption that the guide vane of the hydraulic turbine and the turbine discharge were all changed linearly. An exact maximum of the draft-tube vacuum for the first-phase water-hammer and the last-phase water-hammer is obtained. Finally a much more reasonable formula of critical tailrace length is derived. The results of two cases show that the formula proposed can determine correctly and reasonably whether a tailrace surge tank is needed or not, and are more suitable for project design than the formula suggested by the specification.

  18. Dynamic stall on a pitching and surging airfoil

    Science.gov (United States)

    Dunne, Reeve; McKeon, Beverley J.

    2015-08-01

    Vertical axis wind turbine blades undergo dynamic stall due to the large angle of attack variation they experience during a turbine rotation. The flow over a single blade was modeled using a sinusoidally pitching and surging airfoil in a non-rotating frame with a constant freestream flow at a mean chord Reynolds number of . Two-dimensional, time-resolved velocity fields were acquired using particle image velocimetry. Vorticity contours were used to visualize shear layer and vortex activity. A low-order model of dynamic stall was developed using dynamic mode decomposition, from which primary and secondary dynamic separation modes were identified. The interaction between these two modes was able to capture the physics of dynamic stall and as such can be extended to other turbine configurations and problems in unsteady aerodynamics. Results from the linear pitch/surge frame are extrapolated to the rotating VAWT frame to investigate the behavior of identified flow structures.

  19. 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

  20. 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

  1. Source of a Prominent Poleward Surge During Solar Cycle 24

    CERN Document Server

    Yeates, A R; van Driel-Gesztelyi, L

    2015-01-01

    As an observational case study, we consider the origin of a prominent poleward surge of leading polarity, visible in the magnetic butterfly diagram during Solar Cycle 24. A new technique is developed for assimilating individual regions of strong magnetic flux into a surface flux transport model. By isolating the contribution of each of these regions, the model shows the surge to originate primarily in a single high-latitude activity group consisting of a bipolar active region present in Carrington Rotations 2104-05 (November 2010-January 2011) and a multipolar active region in Rotations 2107-08 (February-April 2011). This group had a strong axial dipole moment opposed to Joy's law. On the other hand, the modelling suggests that the transient influence of this group on the butterfly diagram will not be matched by a large long-term contribution to the polar field, because of its location at high latitude. This is in accordance with previous flux transport models.

  2. The obesity paradox in cardiac arrest patients.

    Science.gov (United States)

    Chalkias, Athanasios; Xanthos, Theodoros

    2014-02-01

    Evidence from clinical cohorts indicates an obesity paradox in overweight and obese patients who seem to have a more favorable short-term and long-term prognosis than leaner patients. Although obese cardiac arrest victims are theoretically more difficult to be resuscitated due to difficulties in providing adequate chest compressions, ventilation, and oxygenation, research so far has shown that there is an obesity paradox in cardiac arrest.

  3. Controlling near shore nonlinear surging waves through bottom boundary conditions

    CERN Document Server

    Mukherjee, Abhik; Kundu, Anjan

    2016-01-01

    Instead of taking the usual passive view for warning of near shore surging waves including extreme waves like tsunamis, we aim to study the possibility of intervening and controlling nonlinear surface waves through the feedback boundary effect at the bottom. It has been shown through analytic result that the controlled leakage at the bottom may regulate the surface solitary wave amplitude opposing the hazardous variable depth effect. The theoretical results are applied to a real coastal bathymetry in India.

  4. Wildlife Poaching: Africa’s Surging Trafficking Threat

    Science.gov (United States)

    2014-05-01

    called keratin, an inert substance that is similar in composition to human fingernails and hair. Some of the consequences of wildlife trafficking are...of the few central figures to have been convicted is a Thai trafficker named Chumlong Lem- tongthai, who worked for businesses in Thailand and Laos...4 1 Wildlife Poaching: Africa’s Surging Trafficking Threat By Bradley anderson and Johan Jooste u Spikes in the prices of ivory and rhino horn have

  5. Enkephalin surges in dorsal neostriatum as a signal to eat

    OpenAIRE

    DiFeliceantonio, Alexandra G.; Mabrouk, Omar S.; Kennedy, Robert T.; C. Berridge, Kent

    2012-01-01

    Compulsive over-consumption of rewards characterizes disorders ranging from binge eating to drug addiction. Here, we provide evidence that enkephalin surges in an anteromedial quadrant of dorsal neostriatum contribute to generating intense consumption of palatable food. In ventral striatum, mu opioid circuitry contributes an important component of motivation to consume rewards [1–4]. In dorsal neostriatum, mu opioid receptors are concentrated within striosomes that receive inputs from limbic ...

  6. Surface Electrocardiogram Predictors of Sudden Cardiac Arrest

    Science.gov (United States)

    Abdelghani, Samy A.; Rosenthal, Todd M.; Morin, Daniel P.

    2016-01-01

    Background: Heart disease is a major cause of death in industrialized nations, with approximately 50% of these deaths attributable to sudden cardiac arrest. If patients at high risk for sudden cardiac arrest can be identified, their odds of surviving fatal arrhythmias can be significantly improved through prophylactic implantable cardioverter defibrillator placement. This review summarizes the current knowledge pertaining to surface electrocardiogram (ECG) predictors of sudden cardiac arrest. Methods: We conducted a literature review focused on methods of predicting sudden cardiac arrest through noninvasive electrocardiographic testing. Results: Several electrocardiographic-based methods of risk stratification of sudden cardiac arrest have been studied, including QT prolongation, QRS duration, fragmented QRS complexes, early repolarization, Holter monitoring, heart rate variability, heart rate turbulence, signal-averaged ECG, T wave alternans, and T-peak to T-end. These ECG findings have shown variable effectiveness as screening tools. Conclusion: At this time, no individual ECG finding has been found to be able to adequately stratify patients with regard to risk for sudden cardiac arrest. However, one or more of these candidate surface ECG parameters may become useful components of future multifactorial risk stratification calculators. PMID:27660578

  7. Population vulnerability to storm surge flooding in coastal Virginia, USA.

    Science.gov (United States)

    Liu, Hua; Behr, Joshua G; Diaz, Rafael

    2016-07-01

    This study aims to assess the vulnerability of populations to storm surge flooding in 12 coastal localities of Virginia, USA. Population vulnerability is assessed by way of 3 physical factors (elevation, slope, and storm surge category), 3 built-up components (road availability, access to hospitals, and access to shelters), and 3 household conditions (storm preparedness, financial constraints to recovering from severe weather events, and health fragility). Fuzzy analysis is used to generate maps illustrating variation in several types of population vulnerability across the region. When considering physical factors and household conditions, the most vulnerable neighborhoods to sea level rise and storm surge flooding are largely found in urban areas. However, when considering access to critical infrastructure, we find rural residents to be more vulnerable than nonrural residents. These detailed assessments can inform both local and state governments in catastrophic planning. In addition, the methodology may be generalized to assess vulnerability in other coastal corridors and communities. The originality is highlighted by evaluating socioeconomic conditions at refined scale, incorporating a broader range of human perceptions and predispositions, and employing a geoinformatics approach combining physical, built-up, and socioeconomic conditions for population vulnerability assessment. Integr Environ Assess Manag 2016;12:500-509. © 2015 SETAC. © 2015 SETAC.

  8. Mass balance, runoff and surges of Bering Glacier, Alaska

    Directory of Open Access Journals (Sweden)

    W. Tangborn

    2013-05-01

    Full Text Available The historical net, ablation and accumulation daily balances, as well as runoff of Bering Glacier, Alaska are determined for the 1951–2011 period with the PTAA (precipitation-temperature-area-altitude model, using daily precipitation and temperature observations collected at the Cordova and Yakutat weather stations, together with the area-altitude distribution of the glacier. The model mean annual balance for this 61 yr period is −0.6 m w.e., the accumulation balance is +1.4 and the ablation balance is −2.0 m w.e. Average annual runoff is 2.5 m w.e. Periodic surges of this glacier transport large volumes of ice to lower elevations where the ablation rate is higher, producing more negative balances and increasing runoff. Runoff from Bering Glacier (derived from simulated ablation and precipitation as rain is highly correlated with four of the glacier surges that have occurred since 1951. Ice volume loss for the 1972–2003 period measured with the PTAA model is 2.7 km3 w.e. a−1 and closely agrees with losses for the same period measured with the geodetic method. It is proposed that the timing and magnitude of daily snow accumulation and runoff, both of which are controlled by the glacier's area-altitude distribution and are calculated with the PTAA model, can be used to determine the probability that a glacier will surge.

  9. New insights in the ongoing surge of the Austfonna icecap

    Science.gov (United States)

    Schellenberger, T.; Dunse, T.; Kääb, A.; Hagen, J. O.; Schuler, T.; Reijmer, C.

    2014-12-01

    Basin-3, a major drainage basin of the Austfonna icecap in NE-Svalbard switched to full surge mode in autumn 2012 after a multiannual, stepwise acceleration of its northern branch. A time series of velocity maps from repeat TerraSAR-X acquisitions revealed a maximum speed at the terminus of >18 m d-1 around the turn of the year 2012. The frontal ablation of Basin-3 was estimated to 4.2±1.6 Gt a-1 between April 2012 and May 2013, tripling the total dynamic mass loss from the largest icecap in the Eurasian arctic. Today, TerraSAR-X, Radarsat-2 and GPS data show that the surge is still ongoing. While the speed at the calving front dropped to 10 m d-1 until July 2014, areas further inland continued to accelerate after the climax, and 10 m d-1 were also measured ~20 km inland in summer 2014. This development will be further investigated by exploiting a time series of velocity maps based on Radarsat-2 Fine Beam data starting from July 2014, which will, other than the TerraSAR-X data, cover almost the entire fast flowing part of the basin. By combining both datasets we will extend the estimation of the frontal ablation and related sea-level rise contribution of the Basin-3 surge.

  10. 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.

  11. Using satellite altimetry and tide gauges for storm surge warning

    Science.gov (United States)

    Andersen, O. B.; Cheng, Y.; Deng, X.; Steward, M.; Gharineiat, Z.

    2015-03-01

    The combination of the coarse temporal sampling by satellite altimeters in the deep ocean with the high temporal sampling at sparsely located tide gauges along the coast has been used to improve the forecast of high water for the North Sea along the Danish Coast and for the northeast coast of Australia. For both locations we have tried to investigate the possibilities and limitations of the use of satellite altimetry to capture high frequency signals (surges) using data from the past 20 years. The two regions are chosen to represent extra-tropical and tropical storm surge conditions. We have selected several representative high water events on the two continents based on tide gauge recordings and investigated the capability of satellite altimetry to capture these events in the sea surface height data. Due to the lack of recent surges in the North Sea we focused on general high water level and found that in the presence of two or more satellites we could capture more than 90% of the high water sea level events. In the Great Barrier Reef section of the northeast Australian coast, we have investigated several large tropical cyclones; one of these being Cyclone Larry, which hit the Queensland coast in March 2006 and caused both loss of lives as well as huge devastation. Here we demonstrate the importance of integrating tide gauges with satellite altimetry for forecasting high water at the city of Townsville in northeast Australia.

  12. Surge dynamics in the Nathorstbreen glacier system, Svalbard

    Directory of Open Access Journals (Sweden)

    M. Sund

    2013-10-01

    Full Text Available Nathorstbreen glacier system (NGS recently experienced the largest surge in Svalbard since 1936, and is examined using spatial and temporal observations from DEM differencing, time-series of surface velocities from satellite synthetic aperture radar (SAR and other sources. The upper basins with maximum accumulation during quiescence correspond to regions of initial lowering. Initial speed-up exceeds quiescent velocities by a factor of several tens of times. This suggests that polythermal glaciers surges are initiated in the temperate area before mass is displaced downglacier. Subsequent downglacier mass displacement coincides with areas of 100–200 times increased velocities (stage 2. After > 5 yr the joint NGS terminus advanced abruptly into tidewater during winter. The advance was followed by upglacier propagation of crevasses, indicating a re-action following from the already displaced mass and extending flow. NGS advanced ca. 15 km, while another ca. 3 km length was lost due to calving. Surface lowering of ca. 50 m was observed in some upglacier areas and during 5 yr the total area increased by 20%. Maximum measured flow rates were at least 25 m d−1, 2500 times quiescence, while average velocities were about 10 m d−1. The surges of Zawadzkibreen cycle with ca. 70 yr periods.

  13. Mass balance, runoff and surges of the Bering Glacier, Alaska

    Directory of Open Access Journals (Sweden)

    W. Tangborn

    2012-12-01

    Full Text Available The historical net, ablation and accumulation daily balances and runoff of the Bering Glacier, Alaska are determined for the 1951–2011 period with the PTAA (precipitation-temperature-area-altitude model, using daily precipitation and temperature observations collected at the Cordova and Yakutat weather stations, together with the area-altitude distribution of the glacier. The mean annual balance for this 61-yr period is −0.6 mwe, the accumulation balance is +1.4 and the ablation balance is −2.0 mwe. Periodic surges of this glacier transport large volumes of ice to lower elevations where the ablation rate is higher, producing more negative balances and increasing runoff. During the 1993–1995 surge the average ablation balance is −3.3 mwe, over a meter greater than the 1951–2011 average. Runoff from the Bering Glacier (derived from simulated ablation and precipitation as rain is highly correlated with the four glacier surges that have been observed since 1951. Ice volume loss for the 1972–2003 period measured with the PTAA model is 2.3 km3 we a−1 and closely agrees with losses for the same period measured with the geodetic method.

  14. H{α} Surges Aroused by Newly-emerging Satellite Bipolar Magnetic Field

    Science.gov (United States)

    Wang, J. F.; Zhou, T. H.; Ji, H. S.

    2013-07-01

    An Hα surge event occurred at AR NOAA 11259 on 2011 July 22. According to the BBSO (Big Bear Solar Observatory) Hα line-center observations, three surges continuously ejected from the same region to the north of the main-sunspot of AR 11259. All of surges ejected along a straight trajectory, and looked like the reversed Eiffel Tower. The first and second surges had the same process. Two bright points firstly appeared to the north of the main-sunspot. After several minutes, a surge appeared between the two bright points, and then rapidly ejected when the two points got most brightness.When the surge reached the maximum height, it disappeared quickly. However, the third surge appeared without bright points, and its height was only half of the others. Compared with SDO/HMI (Solar Dynamics Observatory/Helioseismic and Magnetic Imager) line-of-sight magnetogram, more than one hour before the first surge appeared, a satellite bipolar magnetic field emerged from the surge-ejection region. The newly-emerging positive magnetic flux showed a distinct decrease several minutes earlier than the ejection of the surges. We assumed that the surges was associated with the reconnection between the newly-emerging bipolar magnetic field and the existing (sunspot) magnetic field.

  15. 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.

  16. Can we use crevasse fill ridges for identifying undocumented surge behavior in Svalbard?

    Science.gov (United States)

    Farnsworth, W. R.; Ingolfsson, O.; Schomacker, A.; Retelle, M.

    2015-12-01

    Documenting glaciers that exhibit surge type behavior is crucial, especially as we attempt to use evidence of ice front fluctuations for reconstructing past climate oscillations. Controversy exists regarding the relationship between surge activity and climatic processes such as mass balance. This project identifies undocumented surge type glaciers in Svalbard based on the presence of crevasse fill ridges (CFRs) visible in glacier forelands. Although it is acknowledged that many Svalbard outlet glaciers surge, estimates vary greatly as to the actual number of surge- type glaciers in Svalbard, and their distribution pattern is not well understood. A detailed survey of recent (2008-2011), high resolution imagery from Toposvalbard, provided by the Norwegian Polar Institute, allowed for a rapid analysis of Svalbard outlet glaciers. Using CFRs as indicators of surge behavior has almost doubled the amount of potential surge-type glaciers in central Spitsbergen. This method also highlights numerous other glaciers of potential surge type behavior throughout the archipelago. Limits to the CFR identification method are discussed. Additionally as the forelands of previously reported surge type glaciers were analyzed for CFRs, it was evident that the surge indicators were only present in approximately half of the forelands. Numerous factors control the formation and preservation of CFRs including; glacier size, bedrock lithology, subglacial sediments and clast size as well as glacial fluvial run-off. This poster focuses on the controlling factors for CFR formation and preservation as well as other potential methods for effectively identifying surge behavior.

  17. Sex Disparities in Arrest Outcomes for Domestic Violence

    Science.gov (United States)

    Hamilton, Melissa; Worthen, Meredith G. F.

    2011-01-01

    Domestic violence arrests have been historically focused on protecting women and children from abusive men. Arrest patterns continue to reflect this bias with more men arrested for domestic violence compared to women. Such potential gender variations in arrest patterns pave the way to the investigation of disparities by sex of the offender in…

  18. Cardiac arrest leadership: in need of resuscitation?

    Science.gov (United States)

    Robinson, Philip S; Shall, Emma; Rakhit, Roby

    2016-12-01

    Leadership skills directly correlate with the quality of technical performance of cardiopulmonary resuscitation (CPR) and clinical outcomes. Despite an improved focus on non-technical skills in CPR training, the leadership of cardiac arrests is often variable. To assess the perceptions of leadership and team working among members of a cardiac arrest team and to evaluate future training needs. Cross-sectional survey of 102 members of a cardiac arrest team at an Acute Hospital Trust in the UK with 892 inpatient beds. Responses sought from doctors, nurses and healthcare assistants to 12 rated statements and 4 dichotomous questions. Of 102 responses, 81 (79%) were from doctors and 21 (21%) from nurses. Among specialist registrars 90% agreed or strongly agreed that there was clear leadership at all arrests compared with between 28% and 49% of nurses and junior doctors respectively. Routine omission of key leadership tasks was reported by as many as 80% of junior doctors and 50% of nurses. Almost half of respondents reported non-adherence with Advanced Life Support (ALS) guidelines. Among junior members of the team, 36% felt confident to lead an arrest and 75% would welcome further dedicated cardiac arrest leadership training. Leadership training is integrated into the ALS (Resus Council, UK) qualification. However, this paper found that in spite of this training; standards of leadership are variable. The findings suggest a pressing need for further dedicated cardiac arrest leadership training with a focus on improving key leadership tasks such as role assignment, team briefing and debriefing. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  19. THEORETICAL,NUMERICAL AND EXPERIMENTAL STUDY OF WATER HAMMER IN PIPE SYSTEM WITH COLUMN SURGE CHAMBER

    Institute of Scientific and Technical Information of China (English)

    Zhou Ze-xuan; Tan Soon Keat

    2003-01-01

    A new kind of governing equations for water hammer based on the elastic column theory was proposed and adopted to analyse water hammer phenomenon in the pipe system with a vertical column surge chamber and water level fluctuation in the surge chamber during pressure transient. The wrongness existing in the classical governing equations for water hammer was analysed. A typical reservoir-valve pipe system was chosen as an example to verify the new governing equations numerically and experimentally. The finite difference method based on the method of characteristics was used to solve numerically the nonlinear characteristic equations. The temporal evolutions of transient volume flux and head and of water level fluctuation for various surge chamber configurations were worked out, assuming that the air in the surge chamber are compressible. The relevant experiment was conducted to verify the new governing equations and numerical method. The numerical and experimental results show that the new governing equations are valid and the conventional assumption that the pressure head at the base of a surge chamber equals that of the static head above it during pressure transient is not always valid. The surge chamber generally reises the period of transient pressure wave in pipe system, reduces the maximum pressure envelope and lifts the minimum envelope substantially. The water level fluctuation in the surge chamber was numerically and experimentally observed. Increasing the size of the surge chamber and/or decreasing the initial air pressure in the surge chamber enhance the effectiveness of the surge chamber in suppressing pressure wave.

  20. Effect of hurricane paths on storm surge response at Tianjin, China

    Science.gov (United States)

    Feng, Xingru; Yin, Baoshu; Yang, Dezhou

    2012-06-01

    A hurricane induced storm surge simulation system was developed for Tianjin coast, which consists of a hurricane model and a storm surge model. The peak storm surge result of the simulation agreed well with that of the observation. Three observed paths (Rita, Mimie and WINNIE) and a hypothetical path (Rita2) were chosen as the selective hurricane paths according to their positions relative to Tianjin. The sensitivity of Tianjin storm surge to the four paths was investigated using the validated storm surge simulation system. Three groups of experiments were done. In group one, the models were forced by the wind field and air pressure; in group two and three the models were forced by the wind only and the air pressure only respectively. In the experiments, the hurricane moved with a fixed speed and an intensity of 50 year return period. The simulation results show that path of the type Rita2 is the easiest to cause storm surge disaster in Tianjin, and the effect of air pressure forcing is most evident for path of the type Rita in Tianjin storm surge process. The above conclusions were analyzed through the evolution of the wind fields and the air pressure distributions. Comparing the experiment results of Group one, two and three, it can be seen that the storm surge is mainly induced by the wind forcing and the nonlinear interaction between the effect of wind forcing and air pressure forcing on the storm surge tends to weaken the storm surge.

  1. Direct Surge Margin Control for Aeroengines Based on Improved SVR Machine and LQR Method

    Directory of Open Access Journals (Sweden)

    Haibo Zhang

    2013-01-01

    Full Text Available A novel scheme of high stability engine control (HISTEC on the basis of an improved linear quadratic regulator (ILQR, called direct surge margin control, is derived for super-maneuver flights. Direct surge margin control, which is different from conventional control scheme, puts surge margin into the engine closed-loop system and takes surge margin as controlled variable directly. In this way, direct surge margin control can exploit potential performance of engine more effectively with a decrease of engine stability margin which usually happened in super-maneuver flights. For conquering the difficulty that aeroengine surge margin is undetectable, an approach based on improved support vector regression (SVR machine is proposed to construct a surge margin prediction model. The surge margin modeling contains two parts: a baseline model under no inlet distortion states and the calculation for surge margin loss under supermaneuvering flight conditions. The previous one is developed using neural network method, the inputs of which are selected by a weighted feature selection algorithm. Considering the hysteresis between pilot input and angle of attack output, an online scrolling window least square support vector regression (LSSVR method is employed to firstly estimate inlet distortion index and further compute surge margin loss via some empirical look-up tables.

  2. Assessment of Spatial Distribution and Submerged Scope for Storm Surge in the Pearl River Delta Region

    Institute of Scientific and Technical Information of China (English)

    LI Kuo; LI Guo-sheng

    2011-01-01

    The aim of this study was to explore the spatial distribution and submerged scope for storm surge in the Pearl River Delta (PRD) region.Based on the data of storm surges in the PRD region in the past 30 years, the return periods of 12 tide-gauge stations for storm surges were calculated separately with the methods of Gumbel and Pearson-iii.The data of another six tide-gauge stations in Guangdong Coast was quoted to depict the overall features of storm surges in Guangdong.Using least-square method, the spatial distribution models of storm surges in different retum periods were established to reveal the distribution rule of the set-up values of storm surges.The spatial distribution curves of storm surges in different retum periods in the PRD Region were drawn up based on the models and the terrain of Guangdong Coast.According to the curves, the extreme set-up values of storm surges in 1 000,100, 10 a return periods were determined on each spot of Guangdong Coast.Applying the spatial analysis technology of ArcGIS, with the topography data of the PRD Region, the submerged scopes of flood caused by storm surge in 1 000, 100, 10 a return periods were drawn up.The loss caused by storm surges was estimated.Results showed that the storm surges and the topography of PRD region jointly led to the serious flood in the PRD region.This assessment would be useful for the planning and design department to make decision and provide government scientific basis for storm surge prediction, coastal engineering designing and the prevention of storm surge disaster.

  3. Surges of outlet glaciers from the Drangajökull ice cap, northwest Iceland

    Science.gov (United States)

    Brynjólfsson, Skafti; Schomacker, Anders; Korsgaard, Niels J.; Ingólfsson, Ólafur

    2016-09-01

    Surface elevation and volume changes of the Drangajökull surge-type glaciers, Reykjarfjarðarjökull and Leirufjarðarjökull, were studied by comparing digital elevation models that pre-date and post-date their most recent surges. Annual glacier-frontal measurements were used to estimate average ice velocities during the last surge of the glaciers. The observations show a distinct ice discharge, most of which was from the upper reservoir areas, down to the receiving areas during the surges. The surface draw-down in the reservoir areas was usually 10-30 m during the surges, while the thickening of the receiving areas was significantly more variable, on the order of 10-120 m. Despite a negative geodetic net mass balance derived from the digital elevation models, the reservoir areas have been gaining mass since the surge terminations. This surface thickening along with considerable ablation of the receiving areas will most likely return the glacier surface profiles to the pre-surge stage. Our results indicate that (a) greatest surface thinning in the upper reservoir areas of Drangajökull rather than proximal to the equilibrium line during Vatnajökull surges and (b) development of Drangajökull surges that resembles Svalbard surge-type glaciers rather than Vatnajökull surge-type glaciers. The contrasting surge characteristics could be explained by differences in glacier geometry, topography and substratum of the Drangajökull and Vatnajökull surge-type glaciers.

  4. Arrested larval development in cattle nematodes.

    Science.gov (United States)

    Armour, J; Duncan, M

    1987-06-01

    Most economically important cattle nematodes are able to arrest their larval development within the host - entering a period of dormancy or hypobiosis. Arrested larvae have a low death rate, and large numbers can accumulate in infected cattle during the grazing season. Because of this, outbreaks of disease caused by such nematodes can occur at times when recent infection with the parasites could not have occurred, for example during winter in temperature northern climates when cattle are normally housed. The capacity to arrest is a heritable trait. It is seen as an adaptation by the parasite to avoid further development to its free-living stages during times when the climate is unsuitable for free-living survival. But levels of arrestment can vary markedly in different regions, in different cattle, and under different management regimes. Climatic factors, previous conditioning, host immune status, and farm management all seem to affect arrestment levels. In this article, James Armour and Mary Duncan review the biological basis of the phenomenon, and discuss the apparently conflicting views on how it is controlled.

  5. 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.

  6. Two parametric tropical cyclone models for storm surge modeling

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-li

    2010-01-01

    In this paper,the two parametric tropical cyclone models for storm surge modeling are further developed.The analytical expressions of tangential and radial velocity distribution are derived from the governing momentum equations,based on the general symmetric pressure distribution proposed by Holland and Fujita.On the basis of the data of several tropical cyclones that occurred in East China Ocean,the shape parameter in pressure model is estimated.Finally,the Fred cyclone(typhoon 199417)is calculated,and comparisons of measured and calculated air pressures and wind speed are presented.

  7. Probabilistic modelling of sea surges in coastal urban areas

    Science.gov (United States)

    Georgiadis, Stylianos; Jomo Danielsen Sørup, Hjalte; Arnbjerg-Nielsen, Karsten; Nielsen, Bo Friis

    2016-04-01

    Urban floods are a major issue for coastal cities with severe impacts on economy, society and environment. A main cause for floods are sea surges stemming from extreme weather conditions. In the context of urban flooding, certain standards have to be met by critical infrastructures in order to protect them from floods. These standards can be so strict that no empirical data is available. For instance, protection plans for sub-surface railways against floods are established with 10,000 years return levels. Furthermore, the long technical lifetime of such infrastructures is a critical issue that should be considered, along with the associated climate change effects in this lifetime. We present a case study of Copenhagen where the metro system is being expanded at present with several stations close to the sea. The current critical sea levels for the metro have never been exceeded and Copenhagen has only been severely flooded from pluvial events in the time where measurements have been conducted. However, due to the very high return period that the metro has to be able to withstand and due to the expectations to sea-level rise due to climate change, reliable estimates of the occurrence rate and magnitude of sea surges have to be established as the current protection is expected to be insufficient at some point within the technical lifetime of the metro. The objective of this study is to probabilistically model sea level in Copenhagen as opposed to extrapolating the extreme statistics as is the practice often used. A better understanding and more realistic description of the phenomena leading to sea surges can then be given. The application of hidden Markov models to high-resolution data of sea level for different meteorological stations in and around Copenhagen is an effective tool to address uncertainty. For sea surge studies, the hidden states of the model may reflect the hydrological processes that contribute to coastal floods. Also, the states of the hidden Markov

  8. High Resolution Hurricane Storm Surge and Inundation Modeling (Invited)

    Science.gov (United States)

    Luettich, R.; Westerink, J. J.

    2010-12-01

    Coastal counties are home to nearly 60% of the U.S. population and industry that accounts for over 16 million jobs and 10% of the U.S. annual gross domestic product. However, these areas are susceptible to some of the most destructive forces in nature, including tsunamis, floods, and severe storm-related hazards. Since 1900, tropical cyclones making landfall on the US Gulf of Mexico Coast have caused more than 9,000 deaths; nearly 2,000 deaths have occurred during the past half century. Tropical cyclone-related adjusted, annualized losses in the US have risen from 1.3 billion from 1949-1989, to 10.1 billion from 1990-1995, and $35.8 billion per year for the period 2001-2005. The risk associated with living and doing business in the coastal areas that are most susceptible to tropical cyclones is exacerbated by rising sea level and changes in the characteristics of severe storms associated with global climate change. In the five years since hurricane Katrina devastated the northern Gulf of Mexico Coast, considerable progress has been made in the development and utilization of high resolution coupled storm surge and wave models. Recent progress will be presented with the ADCIRC + SWAN storm surge and wave models. These tightly coupled models use a common unstructured grid in the horizontal that is capable of covering large areas while also providing high resolution (i.e., base resolution down to 20m plus smaller subgrid scale features such as sea walls and levees) in areas that are subject to surge and inundation. Hydrodynamic friction and overland winds are adjusted to account for local land cover. The models scale extremely well on modern high performance computers allowing rapid turnaround on large numbers of compute cores. The models have been adopted for FEMA National Flood Insurance Program studies, hurricane protection system design and risk analysis, and quasi-operational forecast systems for several regions of the country. They are also being evaluated as

  9. Surge-tectonic evolution of southeastern Asia: a geohydrodynamics approach

    Science.gov (United States)

    Meyerhoff, Arthur A.

    The repeated need for ad hoc modifications in plate-tectonic models to explain the evolution of southeastern Asia reveals their inability to fully explain the complex features and dynamics of this region. As one example, the hypothesis does not provide a mechanism to explain the 180° turns and twists along the strike of several foldbelts and island arcs in the region (e.g. Banda arc). Convection-cell configuration renders such 180° contortions and Rayleigh-Bénard-type convection impossible. However, during the last 10 years, new data bearing on the convection-cell problem have become available in the form of seismotomographic images of the earth's interior. These images show that (i) mantle diapirs as proposed by traditional plate-tectonic models do not exist; (ii) there is no discernible pattern of upper or lower mantle convection, and thus no longer an adequate mechanism to move plates; and (iii) the lithosphere above a depth of about 80 km is permeated by an interconnected network of low-velocity channels. Seismic-reflection studies of the low-velocity channels discovered on the seismotomographic images reveal that these channels have walls with a 7.1-7.8 km s -1 P-wave velocity. Commonly, the interiors of the channels are acoustically transparent, with much slower P-wave velocities, in places as low as 5.4 km s -1. The author and co-workers have interpreted the low velocities as evidence for the presence of partial melt in the channels, and they postulated that this melt moves preferentially eastward as a result of the earth's rotation. They named these channels "surge channels" and their new hypothesis for earth dynamics "surge tectonics". Surge channels underlie every type of tectonic belt, which includes mid-ocean ridges, aseismic ridges, continental rifts, strike-slip fracture zones, and foldbelts. In southeastern Asia, surge channels—mainly foldbelts—lie between all platform and cratonic massifs. These massifs, platforms, and tectonics belts

  10. 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...

  11. Simulation of Storm Surge and Wave Due to Typhoon Isewan (5915)

    Institute of Scientific and Technical Information of China (English)

    Jin-Hee YUK; Kyeong Ok KIM; Han Soo LEE; Byung Ho CHOI

    2015-01-01

    An integrally coupled wave-tide-surge model was developed and then applied to the simulation of the wave-typhoon surge for the typhoon Isewan (typhoon Vera (5915)), which is the strongest typhoon that has struck Japan and caused incalculable damage. An integrally coupled tide-surge-wave model using identical and homogeneous meshes in an unstructured grid system was used to correctly resolve the physics of wave-circulation interaction in both models. All model components were validated independently. The storm surge and wave properties such as the surge height, the significant wave height, wave period and direction were reproduced reasonably under the meteorological forcing, which was reprocessed to be close to the observations. The resulting modeling system can be used extensively for the prediction of the storm surge and waves and the usual barotropic forecast.

  12. Effect of PSD on Acoustic Cavitation Surge in Inlet Pipe of Turbopump

    OpenAIRE

    吉田, 義樹; 藤原, 徹也; 南里, 秀明; Yoshida, Yoshiki; Fujiwara, Tetsuya; Nanri, Hideaki

    2013-01-01

    To investigate the effect of PSD on acoustic cavitation surge in turbopump, we conducted analyses with the resistance of PSD as a parameter. Consequently, we found that patterns of the acoustic cavitation surge were classified into three types by the value of the resistance. (1) First (the resistance of the PSD is smaller.), when the frequency of the inertial cavitation surge between the PSD and the turbopump coincides with the acoustic natural frequencies between the tank and the PSD, the ac...

  13. 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.

  14. The 1982 eruptions of El Chichon volcano, Mexico (3): Physical properties of pyroclastic surges

    Science.gov (United States)

    Sigurdsson, H.; Carey, S. N.; Fisher, R. V.

    1987-04-01

    Two major pyroclastic surges generated during the 4 April 1982 eruption of El Chichon devastated an area of 153 km2 with a quasi-radial distribution around the volcano. The hot surge clouds carbonized wood throughout their extent and were too hot to allow accretionary lapilli formation by vapor condensation. Field evidence indicates voidage fraction of 0.99 in the surge cloud with extensive entrainment of air. Thermal calculations indicate that heat content of pyroclasts can heat entrained air and maintain high temperatures in the surge cloud. The dominant bed form of the surge deposits are sand waves shaped in dune forms with vertical form index of 10 20, characterized by stoss-side erosion and lee-side deposition of 1 10 cm reversely graded laminae. A systematic decrease in maximum lithic diameter with distance from source is accompanied by decrease in wavelength and amplitude. Modal analysis indicates fractionation of glass and pumice from the surge cloud relative to crystals, resulting in loss of at least 10% 25% of the cloud mass due to winnowing out of fines during surge emplacement. Greatest fractionation from the -1.0 0.0-∅ grain sizes reflects relatively lower pumice particle density in this range and segregation in the formative stages of the surge cloud. Extensive pumice rounding indicates abrasion during bed-load transport. Flow of pyroclastic debris in the turbulent surge cloud was by combination of bed-load and suspended-load transport. The surges are viewed as expanding pyroclastic gravity flows, which entrain and mix with air during transport. The balance between sedimentation at the base of the surge cloud and expansion due to entrainment of air contributed to low cloud density and internal turbulence, which persisted to the distal edge of the surge zone.

  15. A surge of Perseibreen, Svalbard, examined using aerial photography and ASTER high resolution satellite imagery

    OpenAIRE

    Dowdeswell, Julian A.; Benham, Toby J.

    2003-01-01

    The identification of surge activity is important in assessing the duration of the active and quiescent phases of the surge cycle of Svalbard glaciers. Satellite and aerial photographic images are used to identify and describe the form and flow of Perseibreen, a valley glacier of 59 km2 on the east coast of Spitsbergen. Heavy surface crevassing and a steep ice front, indicative of surge activity, were first observed on Perseibreen in April 2002. Examination of high resolution (15 m) Advanced ...

  16. Projections of extreme storm surge levels along Europe

    Science.gov (United States)

    Vousdoukas, Michalis I.; Voukouvalas, Evangelos; Annunziato, Alessandro; Giardino, Alessio; Feyen, Luc

    2016-11-01

    Storm surges are an important coastal hazard component and it is unknown how they will evolve along Europe's coastline in view of climate change. In the present contribution, the hydrodynamic model Delft3D-Flow was forced by surface wind and atmospheric pressure fields from a 8-member climate model ensemble in order to evaluate dynamics in storm surge levels (SSL) along the European coastline (1) for the baseline period 1970-2000; and (2) during this century under the Representative Concentration Pathways RCP4.5 and RCP8.5. Validation simulations, spanning from 2008 to 2014 and driven by ERA-Interim atmospheric forcing, indicated good predictive skill (0.06 m relative sea level rise (RSLR), can be further enforced by an increase of the extreme SSL, which can exceed 30 % of the RSLR, especially for the high return periods and pathway RCP8.5. This implies that the combined effect could increase even further anticipated impacts of climate change for certain European areas and highlights the necessity for timely coastal adaptation and protection measures. The dataset is publicly available under this link: http://data.jrc.ec.europa.eu/collection/LISCOAST.

  17. 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.

  18. New technology and tool prepared for communication against storm surges.

    Science.gov (United States)

    Letkiewicz, Beata

    2010-05-01

    The aim of the presentation is description of the new technology and tool prepared for communication, information and issue of warnings against storm surges. The Maritime Branch of the Institute of Meteorology and Water Management is responsible for preparing the forecast as warning, where the end users are Government Officials and Public. The Maritime Branch carry out the project "Strengthening the administrative capacity in order to improve the management of Polish coastal zone environment" (supported by a grant from Norway through the Norwegian Financial Mechanism). The expected final result of the project is web site www.baltyk.pogodynka.pl. One of the activities of the project is - set up of information website www.baltyk.pogodynka.pl, giving public access to the complied data. Information on web site: - meta data - marine data (on-line measurement: sea level, water temperature, salinity, oxygen concentration); - data bases of mathematical model outputs - forecast data (sea level, currents); - ice conditions of the Baltic Sea, - instructions, information materials with information of polish coastal zone. The aim of set up of the portal is development of communication between users of the system, exchange of the knowledge of marine environment and natural hazards such as storm surges, improving the ability of the region in the scope of the data management about the sea environment and the coastal zone.

  19. Blunting post-meal glucose surges in people with diabetes

    Institute of Scientific and Technical Information of China (English)

    Elsamma; Chacko

    2016-01-01

    Worldwide, the morbidity and mortality associated with non-communicable diseases have been climbing steadily- with costs aggressively keeping pace. This letter highlights a decidedly low-cost way to address the challenges posed by diabetes. High levels of postprandial blood glucose are disproportionately linked to much of the microvascular damage which, in the end, leads to macrovascular complications and organ failures. Systematically controlling post-meal glucose surges is a critical element of overall glycemic management indiabetes. Diet, exercise and medications form a triad of variables that individuals engaged in diabetes selfmanagement may manipulate to achieve their targeted glucose levels. As a rule, diabetes patients in developing countries as well as those living in the pockets of poverty in the western world cannot afford special diets, medications, glucometers and supplies, lab tests and office visits. Exercise is the one option that is readily accessible to all. Decades of research in laboratory settings, viewed holistically, have established that light to moderate aerobic exercise for up to 60 min starting 30 min after the first bite into a meal can blunt the ensuing glucose surge effectively. Moderate resistance exercise, moderate endurance exercise or a combination of the two, practiced post-meal has also been found to improve many cardio-metabolic markers: Glucose, high density lipoprotein, triglycerides, and markers of oxidative stress. On the other hand, pre-breakfast exercise and high-intensity exercise in general have been decidedly counterproductive.

  20. 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.

  1. Surge protective device response to steep front transient in low voltage circuit

    Energy Technology Data Exchange (ETDEWEB)

    Marcuz, J.; Binczak, S.; Bilbault, J.M. [Universite de Bourgogne, Dijon (France)], Emails: jerome.marcuz@ laposte.net, stbinc@u-bourgogne.fr, bilbault@u-bourgogne.fr; Girard, F. [ADEE Electronic, Pont de Pany (France)

    2007-07-01

    Surge propagation on cables of electrical or data lines leads to a major protection problem as the number of equipment based on solid-state circuits or microprocessors increases. Sub-microsecond components of real surge waveform has to be taken into account for a proper protection even in the case of surges caused by indirect lightning effects. The response of a model of transient voltage suppressor diode based surge protection device (SPD) to fast front transient is analytically studied, then compared to simulations, including the lines connected to the SPD and to the protected equipment. (author)

  2. 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.

  3. Regional frequency analysis of extreme storm surges along the French coast

    Directory of Open Access Journals (Sweden)

    L. Bardet

    2011-06-01

    Full Text Available A good knowledge of extreme storm surges is necessary to ensure protection against flood. In this paper we introduce a methodology to determine time series of skew surges in France as well as a statistical approach for estimating extreme storm surges. With the aim to cope with the outlier issue in surge series, a regional frequency analysis has been carried out for the surges along the Atlantic coast and the Channel coast. This methodology is not the current approach used to estimate extreme surges in France. First results showed that the extreme events identified as outliers in at-site analyses do not appear to be outliers any more in the regional empirical distribution. Indeed the regional distribution presents a curve to the top with these extreme events that a mixed exponential distribution seems to recreate. Thus, the regional approach appears to be more reliable for some sites than at-site analyses. A fast comparison at a given site showed surge estimates with the regional approach and a mixed exponential distribution are higher than surge estimates with an at-site fitting. In the case of Brest, the 1000-yr return surge is 167 cm in height with the regional approach instead of 126 cm with an at-site analysis.

  4. Brief Communication: Twelve-year cyclic surging episode at Donjek Glacier in Yukon, Canada

    Directory of Open Access Journals (Sweden)

    T. Abe

    2015-11-01

    Full Text Available Surge-type glaciers repeat their short active phase and much longer quiescent phase usually every several decades or longer, but detailed observations of the evolution cycles have been limited to a few glaciers. Here we report three surging episodes in 1989, 2001, and 2013 at Donjek Glacier in the Yukon, indicating remarkably regular and short repeat cycles of 12 years. The surging area is limited within the ~ 20 km section from the terminus, where the flow width significantly narrows than upstream, suggesting a strong control of the valley constriction on the surge dynamics.

  5. Dynamics of surge-type glaciers in West Kunlun Shan, Northwestern Tibet

    Science.gov (United States)

    Yasuda, Takatoshi; Furuya, Masato

    2015-11-01

    Here we examine 31 glaciers in the West Kunlun Shan of the northwestern Tibetan Plateau and identify 9 as surge type. The method is based on satellite synthetic aperture radar and Landsat optical images, the former going back to 1992, the latter to 1972. To identify surge-type glaciers, we consider temporal changes in velocity, changes in glacier terminus position, propagation of a surge bulge, presence of looped and/or contoured medial moraines, and extensive crevassing. Other than the nine surge-type glaciers, we identify two that have likely surged, and six that may be surge type. But no glacier surges more than once during the observation period, meaning that the recurrence interval exceeds 42 years. In addition, we examine the evolution of the surface velocities at two surging glaciers with the unprecedented temporal resolution of down to 11 days over ˜7 years. The results show clear seasonal modulations by as much as ˜200% in early winter against those in early summer. This seasonal modulation in surface velocity suggests the presence of surface meltwater that reroutes through the englacial and subglacial drainage systems. Thus, our findings suggest that the hydrological processes originating in the surface meltwater play an important role in maintaining the yearlong active surging phase.

  6. Brief Communication: Twelve-year cyclic surging episodes at Donjek Glacier in Yukon, Canada

    Science.gov (United States)

    Abe, Takahiro; Furuya, Masato; Sakakibara, Daiki

    2016-07-01

    Surge-type glaciers repeat their short active phase and their much longer quiescent phase usually every several decades or longer, but detailed observations of the evolution cycles have been limited to only a few glaciers. Here we report three surging episodes in 1989, 2001, and 2013 at Donjek Glacier in the Yukon, Canada, indicating remarkably regular and short repeat cycles of 12 years. The surging area is limited within the ˜ 20 km section from the terminus, originating in an area where the flow width significantly narrows downstream, suggesting a strong control of the valley constriction on the surge dynamics.

  7. Brief Communication: Twelve-year cyclic surging episode at Donjek Glacier in Yukon, Canada

    Science.gov (United States)

    Abe, T.; Furuya, M.; Sakakibara, D.

    2015-11-01

    Surge-type glaciers repeat their short active phase and much longer quiescent phase usually every several decades or longer, but detailed observations of the evolution cycles have been limited to a few glaciers. Here we report three surging episodes in 1989, 2001, and 2013 at Donjek Glacier in the Yukon, indicating remarkably regular and short repeat cycles of 12 years. The surging area is limited within the ~ 20 km section from the terminus, where the flow width significantly narrows than upstream, suggesting a strong control of the valley constriction on the surge dynamics.

  8. Juvenile Arrests, 2007. Juvenile Justice Bulletin

    Science.gov (United States)

    Puzzanchera, Charles

    2009-01-01

    This Bulletin summarizes 2007 juvenile crime and arrest data reported by local law enforcement agencies across the country and cited in the FBI report, "Crime in the United States 2007." The Bulletin describes the extent and nature of juvenile crime that comes to the attention of the justice system. It serves as a baseline for comparison for…

  9. Het arrest Residex: terugvordering moet, nietigverklaring mag

    NARCIS (Netherlands)

    Montijn, J.; Saanen, N.

    2012-01-01

    Het recente arrest Residex van het Hof van Justitie geeft inzicht in de maatregelen die de nationale rechterlijke instanties kunnen en moeten treffen indien sprake is van onwettige steun. Deze maatregelen zijn niet altijd eenvoudig in het nationale recht te passen. Ook zijn de maatregelen die op gro

  10. 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

  11. Cardiac arrest: comparison of paramedic and conventional ambulance services.

    OpenAIRE

    1983-01-01

    A prospective study conducted in the Greater Vancouver area compared survival rates in prehospital cardiac arrest managed by an advanced life support (paramedic) service with those in cardiac arrest managed by conventional ambulance service. Management by the paramedic service was associated with higher survival rates for patients found in cardiac arrest but not for patients who suffered the arrest while the ambulance was present. Cardiopulmonary resuscitation by bystanders was associated wit...

  12. The "Ram Effect": A "Non-Classical" Mechanism for Inducing LH Surges in Sheep.

    Science.gov (United States)

    Fabre-Nys, Claude; Chanvallon, Audrey; Dupont, Joëlle; Lardic, Lionel; Lomet, Didier; Martinet, Stéphanie; Scaramuzzi, Rex J

    2016-01-01

    During spring sheep do not normally ovulate but exposure to a ram can induce ovulation. In some ewes an LH surge is induced immediately after exposure to a ram thus raising questions about the control of this precocious LH surge. Our first aim was to determine the plasma concentrations of oestradiol (E2) E2 in anoestrous ewes before and after the "ram effect" in ewes that had a "precocious" LH surge (starting within 6 hours), a "normal" surge (between 6 and 28h) and "late» surge (not detected by 56h). In another experiment we tested if a small increase in circulating E2 could induce an LH surge in anoestrus ewes. The concentration of E2 significantly was not different at the time of ram introduction among ewes with the three types of LH surge. "Precocious" LH surges were not preceded by a large increase in E2 unlike "normal" surges and small elevations of circulating E2 alone were unable to induce LH surges. These results show that the "precocious" LH surge was not the result of E2 positive feedback. Our second aim was to test if noradrenaline (NA) is involved in the LH response to the "ram effect". Using double labelling for Fos and tyrosine hydroxylase (TH) we showed that exposure of anoestrous ewes to a ram induced a higher density of cells positive for both in the A1 nucleus and the Locus Coeruleus complex compared to unstimulated controls. Finally, the administration by retrodialysis into the preoptic area, of NA increased the proportion of ewes with an LH response to ram odor whereas treatment with the α1 antagonist Prazosin decreased the LH pulse frequency and amplitude induced by a sexually active ram. Collectively these results suggest that in anoestrous ewes NA is involved in ram-induced LH secretion as observed in other induced ovulators.

  13. Transient Central Diabetes Insipidus and Marked Hypernatremia following Cardiorespiratory Arrest

    Directory of Open Access Journals (Sweden)

    Sahar H. Koubar

    2017-01-01

    Full Text Available Central Diabetes Insipidus is often an overlooked complication of cardiopulmonary arrest and anoxic brain injury. We report a case of transient Central Diabetes Insipidus (CDI following cardiopulmonary arrest. It developed 4 days after the arrest resulting in polyuria and marked hypernatremia of 199 mM. The latter was exacerbated by replacing the hypotonic urine by isotonic saline.

  14. Modes of induced cardiac arrest: hyperkalemia and hypocalcemia - Literature review

    OpenAIRE

    Oliveira,Marcos Aurélio Barboza de; Brandi, Antônio Carlos; dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseini; Cortez, José Luis Lasso; Braile, Domingo Marcolino

    2014-01-01

    The entry of sodium and calcium play a key effect on myocyte subjected to cardiac arrest by hyperkalemia. They cause cell swelling, acidosis, consumption of adenosine triphosphate and trigger programmed cell death. Cardiac arrest caused by hypocalcemia maintains intracellular adenosine triphosphate levels, improves diastolic performance and reduces oxygen consumption, which can be translated into better protection to myocyte injury induced by cardiac arrest.

  15. Designs for surge immunity in critical electronic facilities

    Science.gov (United States)

    Roberts, Edward F., Jr.

    1991-01-01

    In recent years, Federal Aviation Administration (FAA) embarked on a program replacing older tube type electronic equipment with newer solid state equipment. This replacement program dramatically increased the susceptibility of the FAA's facilities to lightning related damages. The proposal is presented of techniques which may be employed to lessen the susceptibility of new FAA electronic facility designs to failures resulting from lightning related surges and transients as well as direct strikes. The general concept espoused is one of a consistent system approach employing both perimeter and internal protection. It compares the technique presently employed to reduce electronic noise with other techniques which reduce noise while lowering susceptibility to lightning related damage. It is anticipated that these techniques will be employed in the design of an Air Traffic Control Tower in a high isokeraunic area. This facility would be subjected to rigorous monitoring over a multi-year period to provide quantitative data hopefully supporting the advantage of this design.

  16. Designs for surge immunity in critical electronic facilities

    Science.gov (United States)

    Roberts, Edward F., Jr.

    1991-08-01

    In recent years, Federal Aviation Administration (FAA) embarked on a program replacing older tube type electronic equipment with newer solid state equipment. This replacement program dramatically increased the susceptibility of the FAA's facilities to lightning related damages. The proposal is presented of techniques which may be employed to lessen the susceptibility of new FAA electronic facility designs to failures resulting from lightning related surges and transients as well as direct strikes. The general concept espoused is one of a consistent system approach employing both perimeter and internal protection. It compares the technique presently employed to reduce electronic noise with other techniques which reduce noise while lowering susceptibility to lightning related damage. It is anticipated that these techniques will be employed in the design of an Air Traffic Control Tower in a high isokeraunic area. This facility would be subjected to rigorous monitoring over a multi-year period to provide quantitative data hopefully supporting the advantage of this design.

  17. SAPS onset timing during substorms and the westward traveling surge

    Science.gov (United States)

    Mishin, Evgeny, V.

    2016-07-01

    We present multispacecraft observations in the magnetosphere and conjugate ionosphere of the onset time of subauroral polarization streams (SAPS) and tens of keV ring current injections on the duskside in three individual substorms. This is probably the first unequivocal determination of the substorm SAPS onset timing. The time lag between the SAPS and substorm onsets is much shorter than the gradient-curvature drift time of ˜10 keV ions in the plasmasphere. It seemingly depends on the propagation time of substorm-injected plasma from the dipolarization onset region to the plasmasphere, as well as on the SAPS position. These observations suggest that fast onset SAPS and ring current injections are causally related to the two-loop system of the westward traveling surge.

  18. Validating the calculated reliability and availability in Dutch storm surge barriers (and other infrastructural works)

    NARCIS (Netherlands)

    Kleijn van Willigen, G.K.; Meerveld, H. van

    2016-01-01

    The reliability and availability of the Dutch storm surge barriers are calculated by probabilistic risk assessment and various underlying risk analysis methods. These calculations, however, focus on the numerical probability of the storm surge barrier functioning adequately, and the implementation o

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

    Energy Technology Data Exchange (ETDEWEB)

    Robert J. Mckee; Danny M. Deffenbaugh

    2003-12-01

    This annual progress report describes the second year's technical progress in a three-year program. This report summarizes what is known about internal flows as surge precursors in centrifugal compressors and focuses on accessing factors that affect pre-surge detection. An attempt is made in this analysis to identify and quantify factors concerning compressor design and operations that affect the detection of pre-surge conditions. This progress report presents results from recent laboratory tests conducted during the course of this second year. This project is co-funded by the Gas Machinery Research Council (GMRC) and by Siemens Energy and Automation (Siemens). The most recently available measured pre-surge internal flow data is parameterized to help identify factors that affect the indications that a compressor is approaching surge. Theoretical arguments are applied to access the factors that influence surge precursors and surge initiation in different centrifugal compressors. This work is considered a step in accessing the factors that affect the success or limitations of pre-surge detection in natural gas pipeline compressors.

  20. 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...

  1. Extreme storm surges: a comparative study of frequency analysis approaches

    Directory of Open Access Journals (Sweden)

    Y. Hamdi

    2013-11-01

    Full Text Available In France, nuclear facilities were designed to very low probabilities of failure. Nevertheless, exceptional climatic events have given rise to surges much larger than observations (outliers and had clearly illustrated the potential to underestimate the extreme water levels calculated with the current statistical methods. The objective of the present work is to conduct a comparative study of three approaches including the Annual Maxima (AM, the Peaks-Over Threshold (POT and the r-Largest Order Statistics (r-LOS. These methods are illustrated in a real analysis case study. All the data sets were screened for outliers. Non-parametric tests for randomness, homogeneity and stationarity of time series were used. The shape and scale parameters stability plots, the mean excess residual life plot and the stability of the standard errors of return levels were used to select optimal thresholds and r values for the POT and r-LOS method, respectively. The comparison of methods was based on: (i the uncertainty degrees, (ii the adequacy criteria and tests and (iii the visual inspection. It was found that the r-LOS and POT methods have reduced the uncertainty on the distributions parameters and return level estimates and have systematically shown values of the 100 and 500 yr return levels smaller than those estimated with the AM method. Results have also shown that none of the compared methods has allowed a good fitting at the right tail of the distribution in the presence of outliers. As a perspective, the use of historical information was proposed in order to increase the representativity of outliers in data sets. Findings are of practical relevance not only to nuclear energy operators in France, for applications in storm surge hazard analysis and flood management, but also for the optimal planning and design of facilities to withstand extreme environmental conditions, with an appropriate level of risk.

  2. Extreme storm surges: a comparative study of frequency analysis approaches

    Science.gov (United States)

    Hamdi, Y.; Bardet, L.; Duluc, C.-M.; Rebour, V.

    2014-08-01

    In France, nuclear facilities were designed around very low probabilities of failure. Nevertheless, some extreme climatic events have given rise to exceptional observed surges (outliers) much larger than other observations, and have clearly illustrated the potential to underestimate the extreme water levels calculated with the current statistical methods. The objective of the present work is to conduct a comparative study of three approaches to extreme value analysis, including the annual maxima (AM), the peaks-over-threshold (POT) and the r-largest order statistics (r-LOS). These methods are illustrated in a real analysis case study. All data sets were screened for outliers. Non-parametric tests for randomness, homogeneity and stationarity of time series were used. The shape and scale parameter stability plots, the mean excess residual life plot and the stability of the standard errors of return levels were used to select optimal thresholds and r values for the POT and r-LOS method, respectively. The comparison of methods was based on (i) the uncertainty degrees, (ii) the adequacy criteria and tests, and (iii) the visual inspection. It was found that the r-LOS and POT methods have reduced the uncertainty on the distribution parameters and return level estimates and have systematically shown values of the 100 and 500-year return levels smaller than those estimated with the AM method. Results have also shown that none of the compared methods has allowed a good fit at the right tail of the distribution in the presence of outliers. As a perspective, the use of historical information was proposed in order to increase the representativeness of outliers in data sets. Findings are of practical relevance, not only to nuclear energy operators in France, for applications in storm surge hazard analysis and flood management, but also for the optimal planning and design of facilities to withstand extreme environmental conditions, with an appropriate level of risk.

  3. Identifying surging glaciers in the Central Karakoram for improved climate change impact assessment

    Science.gov (United States)

    Paul, Frank; Bolch, Tobias; Mölg, Nico; Rastner, Philipp

    2015-04-01

    Several recent studies have investigated glacier changes in the Karakoram mountain range, a region where glaciers behave differently (mass gain and advancing tongues) compared to most other regions in the world. Attribution of this behaviour to climate change is challenging, as many glaciers in the Karakoram are of surge type and have actively surged in the recent past. The measured changes in length, area, volume or velocity in this region are thus depending on the time-period analysed and include non-climatic components. Hence, a proper analysis of climate change impacts on glaciers in this region requires a separation of the surging from the non-surging glaciers. This is challenging as the former often lack the typical surface characteristics such as looped moraines (e.g. when they are steep and small) and/or they merge (during a surge) with a larger non-surging glacier and create looped moraines on its surface. By analysing time series of satellite images that are available since 1961, the heterogeneous behaviour of glaciers in the Karakoram can be revealed. In this study, we have analysed changes in glacier terminus positions in the Karakoram over different time periods from 1961 to 2014 for several hundred glaciers using Corona KH-4 and KH-4B, Hexagon KH-9, Terra ASTER, and Landsat MSS, TM, ETM+ and OLI satellite data. For the last 15 years, high-speed animations of image time-series reveal details of glacier flow and surge dynamics that are otherwise difficult to detect. For example, several of the larger glaciers with surging tributaries (e.g. Panmah, Sarpo Laggo, Skamri, K2 glacier) are stationary and downwasting despite the mass contributions from the surging glaciers. The analysis of the entire time series reveals a complex pattern of changes through time with retreating, advancing, surging and stationary glaciers that are partly regionally clustered. While most of the non-surging glaciers show only small changes in terminus position (±100 m or less

  4. 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

  5. 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.

  6. 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

    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...... margin, where the impact of four surges is evident. Thus, the landscape at Brúarjökull is a product of multiple generations of superimposed landforms associated with extensive sediment transport through subglacial deformation....

  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......, but with the revised statistics using historic evidence, much larger events can be expected. Further, we assess the very large impact of sea level rise on the storm surge statistics. As an example, according to the official statistics of southern Copenhagen, the flooding of a present day 100 year event...

  8. Multivariate extreme value analysis of storm surges in SCS on peak over threshold method

    Directory of Open Access Journals (Sweden)

    Y. Luo

    2015-11-01

    Full Text Available We use a novel statistical approach-MGPD to analyze the joint probability distribution of storm surge events at two sites and present a warning method for storm surges at two adjacent positions in Beibu Gulf, using the sufficiently long field data on surge levels at two sites. The methodology also develops the procedure of application of MGPD, which includes joint threshold and Monte Carlo simulation, to handle multivariate extreme values analysis. By comparing the simulation result with analytic solution, it is shown that the relative error of the Monte Carlo simulation is less than 8.6 %. By running MGPD model based on long data at Beihai and Dongfang, the simulated potential surge results can be employed in storm surge warnings of Beihai and joint extreme water level predictions of two sites.

  9. A new dynamical index for classification of cold surge types over East Asia

    Science.gov (United States)

    Park, Tae-Won; Ho, Chang-Hoi; Jeong, Jee-Hoon; Heo, Jin-Woo; Deng, Yi

    2015-11-01

    The cold surges over East Asia can be classified into wave-train type and blocking type according to their dynamic origins. In the present study, two dynamic indices are proposed to objectively identify cold surge types using potential temperature ( θ) on the dynamic tropopause at 2-potential vorticity units (2-PVU) surface. The two indices are designed to represent primary characteristics of the two types of cold surge. The wave-train index ( WI) is defined as a difference of anomalous θ on the 2-PVU surface between the western North Pacific and northeast China, which captures a southward (northward) intrusion of cold (warm) air mass related to the trough-ridge pattern. The blocking index ( BI) is defined as a difference of anomalous θ between the subarctic region and northeast China, which indicates air mass overturning related to a reversal of the usual meridional θ gradient commonly observed in the occurrence of blocking type cold surge. Composite analyses based on the distribution of the WI and BI clearly demonstrate the dynamic evolutions of corresponding cold surge types. The wave-train cold surge is associated with a southeastward expansion of the Siberian High and northerly wind near surface, which is caused by growing baroclinic waves. During the blocking cold surge, a geopotential height dipole indicating the subarctic blocking and deepening of East Asian coastal trough induces a southward expansion of the Siberian High and northeasterly wind. Compared to the wave-train type, the blocking cold surge exhibits a longer duration and stronger intensity. In the new framework of these dynamic indices, we can detect a third type of cold surge when both the wave-train and the blocking occur together. In addition, we can exclude the events that do not have the essential features of the upper tropospheric disturbances or the subarctic anticyclonic circulation, which are responsible for cold surge occurrence, using the new indices.

  10. Global reconstructed daily surge levels from the 20th Century Reanalysis (1871-2010)

    Science.gov (United States)

    Cid, Alba; Camus, Paula; Castanedo, Sonia; Méndez, Fernando J.; Medina, Raúl

    2017-01-01

    Studying the effect of global patterns of wind and pressure gradients on the sea level variation (storm surge) is a key issue in understanding the recent climate change effect on the dynamical state of the ocean. The analysis of the spatial and temporal variability of storm surges from observations is a difficult task to accomplish since observations are not homogeneous in time, scarce in space, and moreover, their temporal coverage is limited. A recent global surge database developed by AVISO (DAC, Dynamic Atmospheric Correction) fulfilled the lack of data in terms of spatial coverage, but not regarding time extent, since it only includes the last two decades (1992-2014). In this work, we use the 20th Century Reanalysis V2 (20CR), which spans the years 1871 to 2010, to statistically reconstruct daily maximum surge levels at a global scale. A multivariate linear regression model is fitted between daily mean ERA-interim sea level pressure fields and daily maximum surge levels from DAC. Following, the statistical model is used to reconstruct daily surges using mean sea level pressure fields from 20CR. The verification of the statistical model shows good agreements between DAC levels and the reconstructed surge levels from the 20CR. The validation of the reconstructed surge with tide gauges, distributed throughout the domain, shows good accuracy both in terms of high correlations and small errors. A time series comparison is also depicted at specific tide gauges for the beginning of the 20th century, showing a high concordance. Therefore, this work provides to the scientific community, a daily database of maximum surge levels; which correspond to an extension of the DAC database, from 1871 to 2010. This database can be used to improve the knowledge on historical storm surge conditions, allowing the study of their temporal and spatial variability.

  11. Spatial distribution of erosion and deposition during a glacier surge: Brúarjökull, Iceland

    Science.gov (United States)

    Korsgaard, Niels J.; Schomacker, Anders; Benediktsson, Ívar Örn; Larsen, Nicolaj K.; Ingólfsson, Ólafur; Kjær, Kurt H.

    2015-12-01

    Time-series of digital elevation models (DEMs) of the forefield of the Brúarjökull surge-type glacier in Iceland were used to quantify the volume of material that was mobilized by the 1963-1964 surge. The DEMs were produced by stereophotogrammetry on aerial photographs from before the surge (1961) and after (1988 and 2003). The analysis was performed on two DEMs of Difference (DoDs), i.e., a 1961-2003 DoD documenting the impact of the surge and a 1988-2003 DoD documenting the post-surge modification of the juvenile surging glacier landsystem. Combined with a digital geomorphological map, the DoDs allow us to quantify the impact of the surge on a landsystem scale down to individual landforms. A total of 34.2 ± 11.3 × 106 m3 of material was mobilized in the 30.7-km2 study area as a result of the most recent surge event. Of these, 17.4 ± 6.6 × 106 m3 of the material were eroded and 16.8 ± 4.7 × 106 m3 were deposited. More than half of the deposited volume was ice-cored landforms. This study demonstrates that although the total mobilized mass volume is high, the net volume gain of ice and sediment deposited as landforms in the forefield caused by the surge is low. Furthermore, deposition of new dead-ice from the 1963-1964 surge constitutes as much as 64% of the volume gain in the forefield. The 1988-2003 DoD is used to quantify the melt-out of this dead-ice and other paraglacial modification of the recently deglaciated forefield of Brúarjökull.

  12. Secondary pseudohypoaldosteronism causing cardiopulmonary arrest and cholelithiasis.

    Science.gov (United States)

    Kibe, Tetsuya; Sobajima, Takehiro; Yoshimura, Ayumi; Uno, Yuichi; Wada, Naohiro; Ueta, Ikuya

    2014-04-01

    A 4-month-old boy presented with cardiopulmonary arrest on arrival after a brief period of lethargy. Laboratory examination indicated severe hyperkalemia, hyponatremia, metabolic acidosis, and slightly elevated C-reactive protein. Whole body computed tomography identified left-dominant hydronephrosis, hydroureter and cholelithiasis. Despite cardiac arrest >30 min, he was successfully resuscitated and treated with therapeutic hypothermia. Escherichia coli was detected on urine culture. Renal ultrasound showed bilateral hydronephrosis, grade II in the right and grade IV in the left. Retrospective analysis of the blood sample at admission indicated a high level of aldosterone. The patient recovered almost fully with no electrolyte imbalance and normal plasma renin and aldosterone, leading to the diagnosis of secondary pseudohypoaldosteronism associated with bilateral infected hydronephrosis. In this case, cholelithiasis, which may account for chronic dehydration, was a diagnostic clue in the absence of information of pre-existing situations. © 2014 The Authors. Pediatrics International © 2014 Japan Pediatric Society.

  13. 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

  14. Cows are not mice: the role of cyclic AMP, phosphodiesterases, and adenosine monophosphate-activated protein kinase in the maintenance of meiotic arrest in bovine oocytes.

    Science.gov (United States)

    Bilodeau-Goeseels, Sylvie

    2011-01-01

    Meiotic maturation in mammalian oocytes is initiated during fetal development, and is then arrested at the dictyate stage - possibly for several years. Oocyte meiosis resumes in preovulatory follicles in response to the lutenizing hormone (LH) surge or spontaneously when competent oocytes are removed from follicles and cultured. The mechanisms involved in meiotic arrest and resumption in bovine oocytes are not fully understood, and several studies point to important differences between oocytes from rodent and livestock species. This paper reviews earlier and contemporary studies on the effects of cAMP-elevating agents and phosphodiesterase (PDE) enzyme inhibitors on the maintenance of meiotic arrest in bovine oocytes in vitro. Contrary to results obtained with mouse oocytes, bovine oocyte meiosis is inhibited by activators of the energy sensor adenosine monophosphate-activated protein kinase (AMPK, mammalian gene PRKA), which is activated by AMP, the degradation product of cAMP. It is not clear whether or not the effects were due to AMPK activation, and they may depend on culture conditions. Evidence suggests that other signaling pathways (for example, the cGMP/nitric oxide pathway) are involved in bovine oocyte meiotic arrest, but further studies are needed to understand the interactions between the signaling pathways that lead to maturation promoting factor (MPF) being inactive or active. An improved understanding of the mechanisms involved in the control of bovine oocyte meiosis will facilitate better control of the process in vitro, resulting in increased developmental competence and increased efficiency of in vitro embryo production procedures.

  15. Dental Calculus Arrest of Dental Caries

    Science.gov (United States)

    Keyes, Paul H.; Rams, Thomas E.

    2016-01-01

    Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. Materials and methods A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Results Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. Conclusions These observations further document the potential protective effects of dental calculus mineralization against dental caries. PMID:27446993

  16. Nuclear reactor melt arrest and coolability device

    Energy Technology Data Exchange (ETDEWEB)

    Theofanous, Theo G.; Dinh, Nam Truc; Wachowiak, Richard M.

    2016-06-14

    Example embodiments provide a Basemat-Internal Melt Arrest and Coolability device (BiMAC) that offers improved spatial and mechanical characteristics for use in damage prevention and risk mitigation in accident scenarios. Example embodiments may include a BiMAC having an inclination of less than 10-degrees from the basemat floor and/or coolant channels of less than 4 inches in diameter, while maintaining minimum safety margins required by the Nuclear Regulatory Commission.

  17. Rheology and structural arrest of casein suspensions

    OpenAIRE

    Dahbi, Louisa; Alexander, M.; Trappe, Véronique; Dhont, J. K. G.; Schurtenberger, Peter

    2010-01-01

    The rheology of milk powder suspensions is investigated up to very high concentrations, where structural arrest occurs. The main component of the milk powder investigated is casein, so that the suspensions can be regarded as casein suspensions. Four concentration regimes are identified. For effective casein volume fractions less than 0.54 the concentration dependence of the zero-shear viscosity is similar to that of hard-sphere suspensions. However, due to the elastic deformation of the casei...

  18. Aerodynamically generated noise by lightning arrester

    Directory of Open Access Journals (Sweden)

    Váchová J.

    2007-10-01

    Full Text Available This paper presents the general solution of aerodynamically generated noise by lightning arrester. Governing equations are presented in form of Lighthill acoustic analogy, as embodied in the Ffowcs Williams-Hawkings (FW-H equation. This equation is based on conservation laws of fluid mechanics rather than on the wave equation. Thus, the FW-H equation is valid even if the integration surface is in nonlinear region. That’s why the FWH method is superior in aeroacoustics. The FW-H method is implemented in program Fluent and the numerical solution is acquired by Fluent code.The general solution of acoustic signal generated by lightning arrester is shown and the results in form of acoustic pressure and frequency spectrum are presented. The verification of accuracy was made by evaluation of Strouhal number. A comparison of Strouhal number for circumfluence of a cylinder and the lightning arrester was done, because the experimental data for cylinder case are known and these solids are supposed to be respectively in shape relation.

  19. Arrest scenarios in concentrated protein solutions - from hard sphere glasses to arrested spinodal decomposition

    Science.gov (United States)

    Stradner, Anna; Bucciarelli, Saskia; Casal, Lucia; Foffi, Giuseppe; Thurston, George; Farago, Bela; Schurtenberger, Peter

    2014-03-01

    The occurrence of an arrest transition in concentrated colloid suspensions and its dependence on the interaction potential is a hot topic in soft matter. Such arrest transitions can also occur in concentrated protein solutions, as they exist e.g. in biological cells or are increasingly used in pharmaceutical formulations. Here we demonstrate the applicability of concepts from colloid science to understand the dynamics of concentrated protein solutions. In this presentation we report a combination of 3D light scattering, small-angle X-ray scattering and neutron spin echo measurements to study the structural properties as well as the collective and self diffusion of proteins in highly concentrated solutions on the relevant length and time scales. We demonstrate that various arrest scenarios indeed exist for different globular proteins. The proteins chosen are different bovine lens crystallins. We report examples of hard and attractive glass transitions and arrested spinodal decomposition directly linked to the effective pair potentials determined in static scattering experiments for the different proteins. We discuss these different arrest scenarios in view of possible applications of dense protein solutions as well as in view of their possible relevance for living systems.

  20. 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

  1. Arrest History and Intimate Partner Violence Perpetration in a Sample of Men and Women Arrested for Domestic Violence.

    Science.gov (United States)

    Shorey, Ryan C; Ninnemann, Andrew; Elmquist, Joanna; Labrecque, Lindsay; Zucosky, Heather; Febres, Jeniimarie; Brasfield, Hope; Temple, Jeff R; Stuart, Gregory L

    2012-01-01

    Intimate partner violence (IPV) is a serious and prevalent problem throughout the United States. Currently, individuals arrested for domestic violence are often court mandated to batterer intervention programs (BIPs). However, little is known about the arrest histories of these individuals, especially women. The current study examined the arrest histories of men (n = 303) and women (n = 82) arrested for domestic violence and court-referred to BIPs. Results demonstrated that over 30% of the entire sample had been previously arrested for a non-violent offense, and over 25% of the participants had been previously arrested for a violent offense other than domestic violence. Moreover, men were arrested significantly more frequently for violence-related and non-violent offenses than their female counterparts. In addition, men were more likely than women to have consumed binge-levels of alcohol prior to the offense that led to their most recent arrest and court-referral to a BIP. Lastly, arrest history was positively associated with physical and psychological aggression perpetration against an intimate partner for men only, such that more previous arrests were associated with more frequent aggression. These results provide evidence that many men and women arrested for domestic violence have engaged in a number of diverse criminal acts during their lifetimes, suggesting that BIPs may need to address general criminal behavior.

  2. Reconnaissance Level Studies on a Storm Surge Barrier for Flood Risk Reduction in the Houston-Galveston Bay

    NARCIS (Netherlands)

    Jonkman, S.N.; Mooyaart, L.F.; Van Ledden, M.; Stoeten, K.J.; De Vries, P.A.L.; Lendering, K.T.; Van der Toorn, A.; Willems, A.

    2014-01-01

    The Houston - Galveston area is at significant risk from hurricane induced storm surges. This paper summarizes ongoing studies on flood risk reduction for the region. Firstly, based on a simplified probabilistic hurricane surge model , the return periods of surges within the bay have been estimated.

  3. Arresting developments: trends in female arrests for domestic violence and proposed explanations.

    Science.gov (United States)

    Deleon-Granados, William; Wells, William; Binsbacher, Ruddyard

    2006-04-01

    This article represents an effort to generate more systematic and specified discussion on the topic of unintended consequences in the movement to decrease violence against women. In this case, the consequence is increases in female arrests for domestic violence. This article builds on recent discussions by first using a sample of data to examine felony domestic violence arrest rates for men and women. The data support the conclusion that domestic violence arrests of women have increased. Second, the article presents six explanations that are derived from existing literature. Although the authors do not offer empirical tests of these explanations, this presentation can play an important part in better understanding the outcomes of criminal justice policies that are aimed at increasing victim safety.

  4. A preliminary study on the intensity of cold wave storm surges of Laizhou Bay

    Science.gov (United States)

    Li, Xue; Dong, Sheng

    2016-12-01

    Dike failure and marine losses are quite prominent in Laizhou Bay during the period of cold wave storm surges because of its open coastline to the north and flat topography. In order to evaluate the intensity of cold wave storm surge, the hindcast of marine elements induced by cold waves in Laizhou Bay from 1985 to 2004 is conducted using a cold wave storm surge-wave coupled model and the joint return period of extreme water level, concomitant wave height, and concomitant wind speed are calculated. A new criterion of cold wave storm surge intensity based on such studies is developed. Considering the frequency of cold wave, this paper introduces a Poisson trivariate compound reconstruction model to calculate the joint return period, which is closer to the reality. By using the newly defined cold wave storm surge intensity, the `cold wave grade' in meteorology can better describe the severity of cold wave storm surges and the warning level is well corresponding to different intensities of cold wave storm surges. Therefore, it provides a proper guidance to marine hydrological analysis, disaster prevention and marine structure design in Laizhou Bay.

  5. Study on the storm surges induced by cold waves in the Northern East China Sea

    Science.gov (United States)

    Mo, Dongxue; Hou, Yijun; Li, Jian; Liu, Yahao

    2016-08-01

    Cold wave, a kind of severe weather system, can bring strong wind and induce significant sea level rise to the Northern East China Sea. Based on CFSR data, the study shows the monthly distributions of invaded days and the spatiotemporal distributions of cold-wave wind direction and wind speed. A three-dimensional numerical model (ROMS) was developed to study storm surges induced by cold waves. The role of wind direction, wind speed, wind duration, extratropical cyclone and tide-surge interaction is investigated by conducting different sensitivity experiments. The results indicate that storm surges mainly happen at the coasts perpendicular to the wind directions. Surge range and time lag are related to the geometry of the basin and the continental shelf. The response of the sea-level fluctuations to cold wave indicates that there is a positive correlation between crests and wind speed, a negative correlation between troughs and wind speed, but no obvious correlations to wind duration. Coupled weather cold waves, which yield a larger range and a multi-peak structure of surges, can be classified according to cold wave tracks and extratropical cyclones. The tide-surge interaction has an obvious and different effect on the magnitudes and phases of storm surges for different tidal stages.

  6. 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.

  7. Winter speed-up of two surging glaciers in West Kunlun Shan, Northwestern Tibet

    Science.gov (United States)

    Yasuda, T.; Furuya, M.

    2015-12-01

    We detected winter speed-up of two surging glaciers in the West Kunlun Shan (WKS), based on satellite Synthetic Aperture Radar (SAR) images since 2007. Surging glacier is a surge-type glacier in the active phase, flowing rapidly and transporting ice masses into the down-glaciers. The WKS is located in northwestern Tibetan Plateau (TP) and is one of the driest and the coldest place around TP. Accumulation and ablation mostly occur in summer season from May to August [Zhang et al., 1989; Maussion et al., 2014]. Zhang et al. (1989) estimated the annual average precipitation and temperature near the equilibrium line altitude (5930 m) is 300 mm and -13.9 deg. C, respectively. Under this sub-polar environment, polythermal glaciers exist in the WKS [Aniya, 2008]. We detected development of two surging flow with unprecedented temporal resolution up to 11 days. The two surging initiated around 2000 and continued by 2015. Surging flow accelerated at least 200 m/year. Moreover, it seasonally fluctuated their flow speed up to 200% in early winter against those in spring to early summer. The observed seasonal modulation in the surface velocities strongly suggests the presence of surface meltwater and subsequent rerouting through englacial and subglacial drainage system under a years-long surging glacier in the sub-polar environment.

  8. Arrests of women for driving under the influence.

    Science.gov (United States)

    Shore, E R; McCoy, M L; Toonen, L A; Kuntz, E J

    1988-01-01

    Police records of arrests of women in Wichita, Kansas for driving under the influence (DUI) of alcohol for a 5-year period (1980-1984) were studied. The proportion of arrests of women increased from 10.6 to 14.5% of total arrested. Women in their 20s comprised the largest age group; single women were greatly overrepresented. More than one-half of the arrested women were employed outside the home; a substantial proportion (30.8%) were unemployed at the time of arrest. The average blood alcohol level of those tested was 183 mg/dl. Characteristics of arrestees are discussed in terms of changes in the social roles and expectations of women. Although time of arrest was similar to that of men (i.e., night), arrests of women were more evenly spread across the days of the week. Within the 5-year period, the rate of recidivism for DUI was 7.43%. The implications of arrest and recidivism patterns are discussed. A change in legal and arrest procedures was found to have the same effect on arrests of women as it had on those of men, suggesting that the changes did not produce differential treatment by police.

  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 influence of coastal wetlands on hurricane surge in Corpus Christi, TX

    Science.gov (United States)

    Ferreira, C.; Irish, J. L.; Olivera, F.

    2010-12-01

    The State of Texas has historically faced hurricane-related damage episodes, with Ike being the most recent example. It is expected that, in the future, hurricanes will intensify due to climate change causing greater surges, while the attenuating effect of wetlands on storm surges will also be modified due to sea level rise changes in wetland vegetation type and spatial location. Numerical analysis of storm surges is an important instrument to predict and simulate flooding extent and magnitude in coastal areas. Most operational surge models account for the influence of wetlands and other vegetation by momentum loss due to friction at the bottom and by reduction of imposed wind stress. A coupled hydrodynamic model (ADCIRC) and wave model (SWAN) was employed, and wetlands were characterized using Manning’s n, surface canopy, and surface roughness. The wetlands parameters were developed from: 1) the National Land Cover Dataset (NLCD) 1992 and 2001; 2) the National Wetlands Inventory (NWI) 2001. The calibrated coupled model for two historical hurricanes, Bret and Beulah, was used to simulate the storm surge for each scenario. Preliminary results for the sensitivity analyses, for hurricane Bret, comparing the scenarios with parameters developed from NLCD and NWI datasets with four hypothetical scenarios considering very high and low Manning’s n and wind stress (surface canopy) values showed that, for areas inside Nueces Bay, the storm surge high could vary up to four times depending on the parameter selection, for areas inside Corpus Christi Bay, the storm surge high varied around three times and behind the barrier island the storm surge high variation was less than three times. This study is a first step for an evaluation of the impact that sea level rise, climate changed wetlands, wetlands restoration, land use change, and wetlands degradation have on hurricane related surge elevation and extent in the city of Corpus Christi.

  11. 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.

  12. The evolution of a submarine landform record following recent and multiple surges of Tunabreen glacier, Svalbard

    Science.gov (United States)

    Flink, Anne Elina; Noormets, Riko; Kirchner, Nina; Benn, Douglas I.; Luckman, Adrian; Lovell, Harold

    2015-01-01

    This study focuses on the glacial landform record associated with recent surge events of Tunabreen - a calving tidewater glacier in Tempelfjorden, Spitsbergen. Submarine geomorphology and recent terminal fluctuations of Tunabreen's glacier front were studied using high-resolution multibeam-bathymetric data and a range of published and remote-sensing sources, including topographic maps, satellite images and aerial photographs. The retreat moraines in the inner part of Tempelfjorden have been correlated with glacier terminus positions during retreat from the 2004 surge maximum. Glacier surface velocity and ice-front positions derived from high-resolution TerraSAR-X satellite data show ice movements at the glacier front during minor advances of the front in winter when calving is suppressed. This suggests that the moraines have formed annually during quiescent phase winter advances. Tunabreen has experienced three surges since the Little Ice Age (LIA). This is in contrast with most Svalbard surging glaciers which have long quiescent phases and have typically only undergone one or two surges during this time. The landform record in Tempelfjorden is distinguished from previously studied glacier-surge landsystems by four, well-preserved sets of landform assemblages generated by the LIA advance and three subsequent surges, all of which partly modify earlier landform records. Based on the unique landform record in Tempelfjorden, a new conceptual landsystem model for frequently surging glaciers has been put forward improving our understanding of the dynamics of the surging glaciers and, most importantly, how they can be distinguished from the climatically-controlled glaciers in the geological record.

  13. Developing an early warning system for storm surge inundation in the Philippines

    Directory of Open Access Journals (Sweden)

    J. Tablazon

    2014-10-01

    Full Text Available A storm surge is the sudden rise of sea water generated by an approaching storm, over and above the astronomical tides. This event imposes a major threat in the Philippine coastal areas, as manifested by Typhoon Haiyan on 8 November 2013 where more than 6000 people lost their lives. It has become evident that the need to develop an early warning system for storm surges is of utmost importance. To provide forecasts of the possible storm surge heights of an approaching typhoon, 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. Bathymetric data, storm track, central atmospheric pressure, and maximum wind speed were used as parameters for the Japan Meteorological Agency Storm Surge Model. The researchers calculated the frequency distribution of maximum storm surge heights of all typhoons 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 probable area inundation and flood levels of storm surges along coastal areas for a specific PSWS using the results of the frequency distribution. These maps were developed from the time series data of the storm tide at 10 min intervals of all observation points in the Philippines. This information will be beneficial in developing early warnings systems, static maps, disaster mitigation and preparedness plans, vulnerability assessments, risk-sensitive land use plans, shoreline defense efforts, and coastal protection measures. Moreover, these will support the local government units' mandate to raise public awareness, disseminate information about storm surge hazards, and implement

  14. Impact of Low-Level Southerly Surges on Mixed Rossby Gravity Waves over the Central Pacific.

    Science.gov (United States)

    Fukutomi, Y.

    2014-12-01

    This study examines dynamical impacts of lower-tropospheric southerly wind surges originating in midlatitudes of the Southern Hemisphere (SH) on the development of mixed Rossby gravity (MRG) waves over the central Pacific during June-August 1979-2012, through the statistical analysis of the JRA-55 products and NOAA outgoing long wave radiation data. The central Pacific MRG waves are identified by an extended EOF (EEOF) analysis on 2-8-day filtered daily 850-hPa meridional wind anomalies during June-August 1979-2012. Composite analysis based on the leading EEOF time coefficients is able to capture the development of the MRG waves associated with a southerly surge originating in the SH extratropics. As a weak clockwise gyre as a part of an off-equatorial easterly wavetrain moves eastward and southeastward from the off-equatorial eastern Pacific into the equatorial central Pacific, the southerly surge penetrates into the equatorial tropics at around 150W. Then, the clockwise gyre develops into a MRG-type gyre over the central Pacific. A transition from an easterly wave-type gyre into a MRG-type gyre occurs associated with the southerly surge. The southerly surge forms a cross-equatorial flow on the western flank of the MRG-type gyre. The gyre is amplified when the southerly surge reaches the equatorial tropics. At the same time, convection coupled with the MRG-type gyre is enhanced. The southerly surges are originated in the midlatitude South Pacific, and they are induced by synoptic-scale baroclinic disturbances propagating along the SH midlatitude westerly jet. An eddy vorticity budget analysis indicates that the southerly surge plays an important role in spinning up the MRG-type gyre through transient advection of absolute vorticiy. A case study of a MRG-wave event in mid-July 2006 also illustrates development of a MRG wave associated with the southerly surge and an easterly wave-to-MRG wave transition.

  15. Identification of storm surge events over the German Bight from atmospheric reanalysis and climate model data

    Science.gov (United States)

    Befort, D. J.; Fischer, M.; Leckebusch, G. C.; Ulbrich, U.; Ganske, A.; Rosenhagen, G.; Heinrich, H.

    2015-06-01

    A new procedure for the identification of storm surge situations for the German Bight is developed and applied to reanalysis and global climate model data. This method is based on the empirical approach for estimating storm surge heights using information about wind speed and wind direction. Here, we hypothesize that storm surge events are caused by high wind speeds from north-westerly direction in combination with a large-scale wind storm event affecting the North Sea region. The method is calibrated for ERA-40 data, using the data from the storm surge atlas for Cuxhaven. It is shown that using information of both wind speed and direction as well as large-scale wind storm events improves the identification of storm surge events. To estimate possible future changes of potential storm surge events, we apply the new identification approach to an ensemble of three transient climate change simulations performed with the ECHAM5/MPIOM model under A1B greenhouse gas scenario forcing. We find an increase in the total number of potential storm surge events of about 12 % [(2001-2100)-(1901-2000)], mainly based on changes of moderate events. Yearly numbers of storm surge relevant events show high interannual and decadal variability and only one of three simulations shows a statistical significant increase in the yearly number of potential storm surge events between 1900 and 2100. However, no changes in the maximum intensity and duration of all potential events is determined. Extreme value statistic analysis confirms no frequency change of the most severe events.

  16. Identification of storm surge events over the German Bight from atmospheric reanalysis and climate model data

    Directory of Open Access Journals (Sweden)

    D. J. Befort

    2015-06-01

    Full Text Available A new procedure for the identification of storm surge situations for the German Bight is developed and applied to reanalysis and global climate model data. This method is based on the empirical approach for estimating storm surge heights using information about wind speed and wind direction. Here, we hypothesize that storm surge events are caused by high wind speeds from north-westerly direction in combination with a large-scale wind storm event affecting the North Sea region. The method is calibrated for ERA-40 data, using the data from the storm surge atlas for Cuxhaven. It is shown that using information of both wind speed and direction as well as large-scale wind storm events improves the identification of storm surge events. To estimate possible future changes of potential storm surge events, we apply the new identification approach to an ensemble of three transient climate change simulations performed with the ECHAM5/MPIOM model under A1B greenhouse gas scenario forcing. We find an increase in the total number of potential storm surge events of about 12 % [(2001–2100–(1901–2000], mainly based on changes of moderate events. Yearly numbers of storm surge relevant events show high interannual and decadal variability and only one of three simulations shows a statistical significant increase in the yearly number of potential storm surge events between 1900 and 2100. However, no changes in the maximum intensity and duration of all potential events is determined. Extreme value statistic analysis confirms no frequency change of the most severe events.

  17. 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

    2017-03-07

    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;page 1 of 9).

  18. Thermal structure of Svalbard glaciers and implications for thermal switch models of glacier surging

    Science.gov (United States)

    Sevestre, Heïdi; Benn, Douglas I.; Hulton, Nicholas R. J.; Bælum, Karoline

    2015-10-01

    Switches between cold- and warm-based conditions have long been invoked to explain surges of High Arctic glaciers. Here we compile existing and new data on the thermal regime of six glaciers in Svalbard to test the applicability of thermal switch models. Two of the large glaciers of our sample are water terminating while one is land terminating. All three have a well-known surge history. They have a thick basal layer of temperate ice, superimposed by cold ice. A cold terminus forms during quiescence but is mechanically removed by calving on tidewater glaciers. The other three glaciers are relatively small and are either entirely cold or have a diminishing warm core. All three bear evidence of former warm-based thermal regimes and, in two cases, surge-like behavior during the Little Ice Age. In Svalbard, therefore, three types of glaciers have switched from slow to fast flow: (1) small glaciers that underwent thermal cycles during and following the Little Ice Age (switches between cold- and warm-based conditions), (2) large terrestrial glaciers which remain warm based throughout the entire surge cycle but develop cold termini during quiescence, and (3) large tidewater glaciers that remain warm based throughout the surge cycle. Our results demonstrate that thermal switching cannot explain the surges of large glaciers in Svalbard. We apply the concept of enthalpy cycling to the spectrum of surge and surge-like behavior displayed by these glaciers and demonstrate that all Svalbard surge-type glaciers can be understood within a single conceptual framework.

  19. Time-frequency analysis of the Surge Onset in the Centrifugal Blower

    Directory of Open Access Journals (Sweden)

    Liskiewicz Grzegorz

    2015-09-01

    Full Text Available Time frequency analysis of the surge onset was performed in the centrifugal blower. A pressure signal was registered at the blower inlet, outlet and three locations at the impeller shroud. The time-frequency scalograms were obtained by means of the Continuous Wavelet Transform (CWT. The blower was found to successively operate in four different conditions: stable working condition, inlet recirculation, transient phase and deep surge. Scalograms revealed different spectral structures of aforementioned phases and suggest possible ways of detecting the surge predecessors.

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

    Institute of Scientific and Technical Information of China (English)

    LUO Yu; WANG Yan-li; WU Ying-biao; XU Yao; Geoffrey A.Head; Macgrathy Barry; LIANG Yu-lu

    2013-01-01

    Background 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.Methods 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.Results 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 <0.05) than in the normotensive group.The rate of morning surge in BP was found to be correlated with the daytime SBP (r=0.236,P <0.01),the difference between the day and night plateau (r=0.249,P <0.01),and the night SBP (r=-0.160,P <0.05),respectively.After controlling for age,sex,and mean systolic pressure within 24 hours (24 h SBP),the rate of morning surge in SBP was closely correlated with daytime SBP (r=0.463,P <0.001),night SBP (r=-0.173,P <0.05),and the difference between the day and night plateau (r=0.267,P <0.001).Logistic regression analysis revealed that the rate of morning surge in SBP was an independent determinant of myocardial infarction (OR=1.266,95% CI=1.153-1.389,P

  1. 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.

  2. 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.

  3. Southeastern Regional Pediatric Disaster Surge Network: a public health partnership.

    Science.gov (United States)

    Ginter, Peter M; Rucks, Andrew C; Duncan, W Jack; Wingate, Martha S; Beeman, S Kenn; Reeves, Jane; West, Maury A

    2010-01-01

    In the event of a natural or man-made disaster involving large numbers of children, resources in the Southeastern U.S. are extremely limited. This article chronicles the efforts of the Alabama Department of Public Health, the Mississippi State Department of Health, and the South Central Center for Public Health Preparedness in conjunction with more than 40 organizations to develop a voluntary network of health-care providers, public health departments, volunteers, and emergency responders from Alabama, Florida, Louisiana, Mississippi, and Tennessee. The purpose of the Southeastern Regional Pediatric Disaster Surge Network (the Network) is to improve the pediatric preparedness response strategies of public health, emergency response, and pediatric providers in the event of large-scale emergencies or disasters that overwhelm local or state pediatric resources. The planning and development of the Network is proceeding through three general phases--information sharing, mutual goal setting and collective action, and long-term formal linkages. In Phase 1, critical planning tasks to be undertaken in the development of the Network were identified. In Phase 2, the agencies developed a draft operational handbook that served as the basis for a formal memorandum of understanding. In Phase 3, participants will engage in exercises and evaluations that will further identify and work out logistical and operational details.

  4. Hydroxylated PBDEs induce developmental arrest in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Usenko, Crystal Y., E-mail: Crystal_usenko@baylor.edu; Hopkins, David C.; Trumble, Stephen J., E-mail: Stephen_trumble@baylor.edu; Bruce, Erica D., E-mail: Erica_bruce@baylor.edu

    2012-07-01

    The ubiquitous spread of polybrominated diphenyl ethers (PBDEs) has led to concerns regarding the metabolites of these congeners, in particular hydroxylated PBDEs. There are limited studies regarding the biological interactions of these chemicals, yet there is some concern they may be more toxic than their parent compounds. In this study three hydroxylated PBDEs were assessed for toxicity in embryonic zebrafish: 3-OH-BDE 47, 5-OH-BDE 47, and 6-OH-BDE 47. All three congeners induced developmental arrest in a concentration-dependent manner; however, 6-OH-BDE 47 induced adverse effects at lower concentrations than the other congeners. Furthermore, all three induced cell death; however apoptosis was not observed. In short-term exposures (24–28 hours post fertilization), all hydroxylated PBDEs generated oxidative stress in the region corresponding to the cell death at 5 and 10 ppm. To further investigate the short-term effects that may be responsible for the developmental arrest observed in this study, gene regulation was assessed for embryos exposed to 0.625 ppm 6-OH-BDE 47 from 24 to 28 hpf. Genes involved in stress response, thyroid hormone regulation, and neurodevelopment were significantly upregulated compared to controls; however, genes related to oxidative stress were either unaffected or downregulated. This study suggests that hydroxylated PBDEs disrupt development, and may induce oxidative stress and potentially disrupt the cholinergic system and thyroid hormone homeostasis. -- Highlights: ► OH-PBDEs induce developmental arrest in a concentration-dependent manner. ► Hydroxyl group location influences biological interaction. ► OH-PBDEs induce oxidative stress. ► Thyroid hormone gene regulation was disrupted following exposure. ► To our knowledge, this is the first whole organism study of OH-PBDE toxicity.

  5. Predictors for outcome among cardiac arrest patients

    DEFF Research Database (Denmark)

    Wibrandt-Johansen, Ida Maria; Norsted, Kristine; Schmidt, Henrik

    2015-01-01

    BackgroundIn the past decade, early treatment of cardiac arrest (CA) victims has been improved in several ways, leading to more optimistic over all prognoses. However, the global survival rate after out-of-hospital CA (OHCA) is still not more than 5-10%. With a better knowledge of the predictors...... circulation (ROSC).ResultsThe overall mortality was 44% and a favorable neurological outcome was seen among 52%. Strong predictors for survival and favorable neurological outcome were ventricular tachycardia/ventricular fibrillation (VT/VF) as initial rhythm, cardiac etiology and time to ROSC¿... rhythm of VT/VF and a cardiac etiology were the strongest....

  6. A case of thyroid storm with cardiac arrest

    Directory of Open Access Journals (Sweden)

    Nakashima Y

    2014-05-01

    Full Text Available Yutaka Nakashima,1 Tsuneaki Kenzaka,2 Masanobu Okayama,3 Eiji Kajii31Department for Support of Rural Medicine, Yamaguchi Grand Medical Center, 2Division of General Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Shimotsuke, Japan; 3Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Shimotsuke, JapanAbstract: A 23-year-old man became unconscious while jogging. He immediately received basic life support from a bystander and was transported to our hospital. On arrival, his spontaneous circulation had returned from a state of ventricular fibrillation and pulseless electrical activity. Following admission, hyperthyroidism led to a suspicion of thyroid storm, which was then diagnosed as a possible cause of the cardiac arrest. Although hyperthyroidism-induced cardiac arrest including ventricular fibrillation is rare, it should be considered when diagnosing the cause of treatable cardiac arrest.Keywords: hyperthyroidism, ventricular fibrillation, treatable cardiac arrest, cardiac arrest, cardiopulmonary arrest

  7. Postoperative cardiac arrest in children with congenital heart abnormalities

    OpenAIRE

    2013-01-01

    BACKGROUND The exact survival rates and markers of survival after postoperative cardiac arrest in children with congenital heart abnormalities are unknown. METHODS In this one-year study, we identified children younger than seven years of age with postoperative cardiac arrest in our pediatric cardiac intensive care unit database. Parameters from perioperative, pre-arrest, and resuscitation periods were analyzed for these patients. Comparisons were made between survivors and non-survivors afte...

  8. Multi-Output Artificial Neural Network for Storm Surge Prediction in North Carolina

    CERN Document Server

    Bezuglov, Anton; Santiago, Reinaldo

    2016-01-01

    During hurricane seasons, emergency managers and other decision makers need accurate and `on-time' information on potential storm surge impacts. Fully dynamical computer models, such as the ADCIRC tide, storm surge, and wind-wave model take several hours to complete a forecast when configured at high spatial resolution. Additionally, statically meaningful ensembles of high-resolution models (needed for uncertainty estimation) cannot easily be computed in near real-time. This paper discusses an artificial neural network model for storm surge prediction in North Carolina. The network model provides fast, real-time storm surge estimates at coastal locations in North Carolina. The paper studies the performance of the neural network model vs. other models on synthetic and real hurricane data.

  9. More Research Shows Big Surge in U.S. Opioid Use, Addictions

    Science.gov (United States)

    ... Research Shows Big Surge in U.S. Opioid Use, Addictions Report from major insurer shows more than 20 ... Health News on Health Disparities Opioid Abuse and Addiction Recent Health News Related MedlinePlus Health Topics Health ...

  10. 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...

  11. 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...

  12. 3D Simulations of a Pyroclastic Surge as an Example of a Compressible Suspension Flow

    National Research Council Canada - National Science Library

    ISHIMINE, Yasuhiro

    2004-01-01

    .... As a conspicuous example of such a flow, we present three-dimensional numerical simulations of a pyroclastic surge, which spreads laterally over the ground surface during some volcanic eruptions...

  13. Lethal thermal impact at periphery of pyroclastic surges: evidences at Pompeii

    National Research Council Canada - National Science Library

    Mastrolorenzo, Giuseppe; Petrone, Pierpaolo; Pappalardo, Lucia; Guarino, Fabio M

    2010-01-01

    The evaluation of mortality of pyroclastic surges and flows (PDCs) produced by explosive eruptions is a major goal in risk assessment and mitigation, particularly in distal reaches of flows that are often heavily urbanized...

  14. Lethal Thermal Impact at Periphery of Pyroclastic Surges: Evidences at Pompeii: e11127

    National Research Council Canada - National Science Library

    Giuseppe Mastrolorenzo; Pierpaolo Petrone; Lucia Pappalardo; Fabio M Guarino

    2010-01-01

      Background The evaluation of mortality of pyroclastic surges and flows (PDCs) produced by explosive eruptions is a major goal in risk assessment and mitigation, particularly in distal reaches of flows that are often heavily urbanized...

  15. 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.

  16. Three-Dimensional Numerical Analysis of Compound Lining in Complex Underground Surge-Shaft Structure

    Directory of Open Access Journals (Sweden)

    Juntao Chen

    2015-01-01

    Full Text Available The mechanical behavior of lining structure of deep-embedded cylinder surge shaft with multifork tunnel is analyzed using three-dimensional nonlinear FEM. With the elastic-plastic constitutive relations of rock mass imported and the implicit bolt element and distributed concrete cracking model adopted, a computing method of complex surge shaft is presented for the simulation of underground excavations and concrete lining cracks. In order to reflect the interaction and initial gap between rock mass and concrete lining, a three-dimensional nonlinear interface element is adopted, which can take into account both the normal and tangential characteristics. By an actual engineering computation, the distortion characteristics and stress distribution rules of the dimensional multifork surge-shaft lining structure under different behavior are revealed. The results verify the rationality and feasibility of this computation model and method and provide a new idea and reference for the complex surge-shaft design and construction.

  17. 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...

  18. Global reconstructed daily storm surge levels from the 20th century reanalysis (1871-2010)

    Science.gov (United States)

    Cid, Alba; Camus, Paula; Castanedo, Sonia; Mendez, Fernando; Medina, Raul

    2015-04-01

    The study of global patterns of wind and pressure gradients, and more specifically, their effect on the sea level variation (storm surge), is a key issue in the understanding of recent climate changes. The local effect of storm surges on coastal areas (zones particularly vulnerable to climate variability and changes in sea level), is also of great interest in, for instance, flooding risk assessment. Studying the spatial and temporal variability of storm surges from observations is a difficult task to accomplish since observations are not homogeneous in time and scarce in space, and moreover, their temporal coverage is limited. The development of a global storm surge database (DAC, Dynamic Atmospheric Correction by Aviso, Carrère and Lyard, 2003) fulfils the lack of data in terms of spatial coverage, but not regarding time extent since it only includes last couple of decades (1992-2014). In this work, we propose the use of the 20CR ensemble (Compo et al., 2011) which spans from 1871 to 2010 to statistically reconstruct storm surge at a global scale and for a long period of time. Therefore, the temporal and spatial variability of storm surges can be fully studied and with much less effort than performing a dynamical downscaling. The statistical method chosen to carry out the reconstruction is based on multiple linear regression between an atmospheric predictor and the storm surge level at daily scale (Camus et al., 2014). The linear regression model is calibrated and validated using daily mean sea level pressure fields (and gradients) from the ERA-interim reanalysis and daily maxima surges from DAC. The obtained daily database of maximum daily surges has allowed us to estimate global trends at a centennial scale and analyse the effect of the changing climate on storm surges during the 20th century. Hence, this work improves the knowledge on historical storm-surge conditions and provides helpful information to the community concern on marine climate evolution and

  19. On the 'real' mass loss of some surging glaciers in the central Karakoram

    Science.gov (United States)

    Paul, Frank

    2016-04-01

    Several assessments of the mass changes of surging glaciers in the central Karakoram (and elsewhere) have shown near-zero changes over the typically decadal-long observation periods. This is in line with the theory that during a surge mass from a reservoir area is moved down-glacier to a receiving area with limited overall change. The resulting elevation changes of the glacier surface as determined by differencing DEMs from two points in time show a typical pattern (decreasing at higher, increasing at lower elevations) with a possible strong frontal advance (km scale) of the terminus. However, this is only half of the story as the observed mass gain at lower elevations is ultimately also a loss. This loss can only be determined when it is calculated separately and when sufficiently precise DEMs from the beginning and the end of a surge are available for each individual glacier. As the latter are hard to obtain, this study presents a simplified geomorphometric approach to approximate a potential maximum surge volume for 20 glaciers with a channel-like glacier fore field. By assuming a semi-elliptical cross-section of the channels, simple measurements of their average width, height and length in Google Earth provide the volume. Further glacier-specific parameters are taken from a recently compiled glacier inventory (area, slope) and Google Earth (minimum length and highest/lowest elevations) to obtain characteristics such as elevation ranges and volume. The average annual specific volume loss for each glacier is then determined by dividing the calculated surge volumes by the respective glacier area and the duration of a full surge cycle (obtained in a previous study). Which glacier area (minimum?) and surge duration (only the active phase?) have to be taken for this calculation is likely a matter of debate. With surge distances between about 1 and 5 km and channel widths (heights) between 300 and 700 (50 and 125) m, the surge volumes vary between 15 and 250 (mean 80

  20. An Analysis of Air Force Systems Command’s Industrial Surge Preparedness Planning.

    Science.gov (United States)

    1987-09-01

    have you taken related to suroe preparedness planning? Only three participants stated that they had taken the * basic production management courses AFIT...program phase was/(will) surge planning initially (be) put on contract? a. Suroe not applicable b. Concept Exploration c. Demonstration/Validation d...constantly. (2) Bad answers - Surge is problem in avionics only if suroes requires more test equipment to build upon to suroe rate. 7 esl equipment at least

  1. 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.

  2. A time series of TanDEM-X digital elevation models to monitor a glacier surge

    Science.gov (United States)

    Wendt, Anja; Mayer, Christoph; Lambrecht, Astrid; Floricioiu, Dana

    2016-04-01

    Bivachny Glacier, a tributary of the more than 70 km long Fedchenko Glacier in the Pamir Mountains, Central Asia, is a surge-type glacier with three known surges during the 20th century. In 2011, the most recent surge started which, in contrast to the previous ones, evolved down the whole glacier and reached the confluence with Fedchenko Glacier. Spatial and temporal glacier volume changes can be derived from high-resolution digital elevation models (DEMs) based on bistatic InSAR data from the TanDEM-X mission. There are nine DEMs available between 2011 and 2015 covering the entire surge period in time steps from few months up to one year. During the surge, the glacier surface elevation increased by up to 130 m in the lower part of the glacier; and change rates of up to 0.6 m per day were observed. The surface height dataset was complemented with glacier surface velocity information from TerraSAR-X/ TanDEM-X data as well as optical Landsat imagery. While the glacier was practically stagnant in 2000 after the end of the previous surge in the 1990s, the velocity increase started in 2011 in the upper reaches of the ablation area and successively moved downwards and intensified, reaching up to 4.0 m per day. The combination of surface elevation changes and glacier velocities, both of high temporal and spatial resolution, provides the unique opportunity to describe and analyse the evolution of the surge in unprecedented detail. Especially the relation between the mobilization front and the local mass transport provides insight into the surge dynamics.

  3. 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)

    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.

  4. 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.

  5. Operation Duty of Metal Oxide Surge Arresters at Lightning Surge%雷电冲击下金属氧化物避雷器动作负荷研究

    Institute of Scientific and Technical Information of China (English)

    郭洁; 刘良壁; 朱跃

    2005-01-01

    通过对110、35 kV金属氧化物避雷器(MOA)电阻片φ70×20、φ56×20在高幅值雷电波冲击下伏安特性和动作负荷特性的实验研究,借助MOA电阻片的微观结构理论,从电场应力、热应力及避雷器的吸收能量几方面阐述了雷电波冲击下MOA的动作负荷、损坏机理,分析了雷电过电压对避雷器的损坏机理和影响因素,指出高幅值、陡波瞬时冲击下电阻片瞬时电流的极不均匀分布引起的内部热应力是导致电阻片损坏的主要原因.

  6. Linkage of Rainfall-Runoff and Hurricane Storm Surge in Galveston Bay

    Science.gov (United States)

    Deitz, R.; Christian, J.; Wright, G.; Fang, N.; Bedient, P.

    2012-12-01

    In conjunction with the SSPEED Center, large rainfall events in the upper Gulf of Mexico are being studied in an effort to help design a surge gate to protect the Houston Ship Channel during hurricane events. The ship channel is the world's second largest petrochemical complex and the Coast Guard estimates that a one-month closure would have a $60 billion dollar impact on the national economy. In this effort, statistical design storms, such as the 24-hour PMP, as well as historical storms, like Hurricane Ike, Hurricane Katrina, and Hurricane Rita, are being simulated in a hydrologic/hydraulic model using radar and rain gauge data. VfloTM, a distributed hydrologic model, is being used to quantify the effect that storm size, intensity, and location has on timing and peak flows in the in the upper drainage area. These hydrographs were input to a hydraulic model with various storm surges from Galveston Bay. Results indicate that there is a double peak phenomenon with flows from the west draining days earlier than flows from the north. With storm surge typically lasting 36-48 hours, this indicates the flows from the west are interacting with the storm surge, whereas flows from the north would arrive once the storm surge is receding. Gate operations were optimized in the model to account for the relative timing of upland runoff and hurricane surge, and to quantify the capability of the gate structure to protect the Ship Channel industry.

  7. Modeling Flood Inundation Induced by River Flow and Storm Surges over a River Basin

    Directory of Open Access Journals (Sweden)

    Wei-Bo Chen

    2014-10-01

    Full Text Available Low-lying coastal regions and their populations are at risk during storm surge events and high freshwater discharges from upriver. An integrated storm surge and flood inundation modeling system was used to simulate storm surge and inundation in the Tsengwen River basin and the adjacent coastal area in southern Taiwan. A three-dimensional hydrodynamic model with an unstructured grid was used, which was driven by the tidal elevation at the open boundaries and freshwater discharge at the upriver boundary. The model was validated against the observed water levels for three typhoon events. The simulation results for the model were in reasonable agreement with the observational data. The model was then applied to investigate the effects of a storm surge, freshwater discharge, and a storm surge combined with freshwater discharge during an extreme typhoon event. The super Typhoon Haiyan (2013 was artificially shifted to hit Taiwan: the modeling results showed that the inundation area and depth would cause severe overbank flow and coastal flooding for a 200 year return period flow. A high-resolution grid model is essential for the accurate simulation of storm surges and inundation.

  8. 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.

  9. 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.

  10. 3D Simulation of Storm Surge Disaster Based on Scenario Analysis

    Institute of Scientific and Technical Information of China (English)

    王晓玲; 孙小沛; 张胜利; 孙蕊蕊; 李瑞金; 朱泽彪

    2016-01-01

    The occurrence of storm surge disaster is often accompanied with floodplain, overflow, dike breach and other complex phenomena, while current studies on storm surge flooding are more concentrated on the 1D/2D numerical simulation of single disaster scenario (floodplain, overflow or dike breach), ignoring the composite ef-fects of various phenomena. Therefore, considering the uncertainty in the disaster process of storm surge, scenario analysis was firstly proposed to identify the composite disaster scenario including multiple phenomena by analyzing key driving forces, building scenario matrix and deducing situation logic. Secondly, by combining the advantages of k-ωand k-εmodels in the wall treatment, a shear stress transmission k-ωmodel coupled with VOF was proposed to simulate the 3D flood routing for storm surge disaster. Thirdly, risk degree was introduced to make the risk analysis of storm surge disaster. Finally, based on the scenario analysis, four scenarios with different storm surge intensity (100-year and 200-year frequency) were identified in Tianjin Binhai New Area. Then, 3D numerical simulation and risk map were made for the case.

  11. Cortisol interferes with the estradiol-induced surge of luteinizing hormone in the ewe.

    Science.gov (United States)

    Wagenmaker, Elizabeth R; Breen, Kellie M; Oakley, Amy E; Pierce, Bree N; Tilbrook, Alan J; Turner, Anne I; Karsch, Fred J

    2009-03-01

    Two experiments were conducted to test the hypothesis that cortisol interferes with the positive feedback action of estradiol that induces the luteinizing hormone (LH) surge. Ovariectomized sheep were treated sequentially with progesterone and estradiol to create artificial estrous cycles. Cortisol or vehicle (saline) was infused from 2 h before the estradiol stimulus through the time of the anticipated LH surge in the artificial follicular phase of two successive cycles. The plasma cortisol increment produced by infusion was approximately 1.5 times greater than maximal concentrations seen during infusion of endotoxin, which is a model of immune/inflammatory stress. In experiment 1, half of the ewes received vehicle in the first cycle and cortisol in the second; the others were treated in reverse order. All ewes responded with an LH surge. Cortisol delayed the LH surge and reduced its amplitude, but both effects were observed only in the second cycle. Experiment 2 was modified to provide better control for a cycle effect. Four treatment sequences were tested (cycle 1-cycle 2): vehicle-vehicle, cortisol-cortisol, vehicle-cortisol, cortisol-vehicle. Again, cortisol delayed but did not block the LH surge, and this delay occurred in both cycles. Thus, an elevation in plasma cortisol can interfere with the positive feedback action of estradiol by delaying and attenuating the LH surge.

  12. 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.

  13. An ensemble study of extreme North Sea storm surges in a changing climate

    Directory of Open Access Journals (Sweden)

    A. Sterl

    2009-05-01

    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. 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. Annual bed statistics give a misleading picture of hospital surge capacity.

    Science.gov (United States)

    DeLia, Derek

    2006-10-01

    I describe how annual hospital surge capacity is affected by within-year variation in patient volume and bed supply. Surge capacity was measured as the percentage and total number of hospital beds that are not occupied by patients. Administrative data were used to calculate these bed statistics for 78 hospitals in New Jersey--statewide and by emergency planning regions--in 2003. Annual bed statistics were compared to more refined calculations for each day of the year. Calculated numbers of empty beds were compared to federal disaster planning benchmarks. Annual bed statistics showed no major limitations on surge capacity. Statewide occupancy rates were well below 80% (ie, more than 20% of beds were empty), and the number of empty beds that were set up and staffed (ie, maintained) was well above federal disaster planning benchmarks. In contrast, daily bed statistics reveal long periods in 2003 when regional and statewide surge capacity was severely strained. Strained capacity was most likely to occur on Tuesdays through Fridays and least likely to occur on weekends. On 212 days, statewide occupancy of maintained beds met or exceeded 85%. This occupancy rate met or exceeded 90% and 95% on 88 and 4 days, respectively. On 288 days, the statewide number of empty maintained beds fell below the federal planning benchmark. Annual bed statistics give a misleading picture of hospital surge capacity. Analysis of surge capacity should account for daily variation in patient volume and within-year variation in bed supply.

  15. 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

  16. Requirement of ultra-high voltage GIS arrester to voltage gradient of metal-oxide varistor

    Institute of Scientific and Technical Information of China (English)

    HE JinLiang; HU Jun; MENG BoWen; ZHANG Bo; ZHU Bin; CHEN ShuiMing; ZENG Rong

    2009-01-01

    The surge arrestor with excellent protection characteristics would decrease the overvoltage level ap-plied on the power apparatus to reduce their insulation levels and manufacturing bottleneck. The ar-restor for the 1000-kV ultra-high voltage ac power transmission system is designed as tank-type structure. The field-circuit combination numerical method combining the three-dimensional finite ele-ment method with circuit is proposed to analyze the potential distribution of GIS arrester. By comparing several design schemes, the most effective method to improve the potential distribution along the varistor column is to increase the voltage gradient of the ZnO varistor. Synthesizing several influential factors, the suitable voltage gradient of ZnO varistor should be controlled to 435 V/mm, and the re-sulted nonuniform degree of the potential distribution along the varistor column inside the GIS arrestor would be controlled smaller than 10%. The result in this paper provides the fundamental technical in-dex for the study of the high voltage gradient ZnO varistors.

  17. Neural Correlates of Consciousness at Near-Electrocerebral Silence in an Asphyxial Cardiac Arrest Model.

    Science.gov (United States)

    Lee, Donald E; Lee, Lauren G; Siu, Danny; Bazrafkan, Afsheen K; Farahabadi, Maryam H; Dinh, Tin J; Orellana, Josue; Xiong, Wei; Lopour, Beth A; Akbari, Yama

    2017-04-01

    Recent electrophysiological studies have suggested surges in electrical correlates of consciousness (i.e., elevated gamma power and connectivity) after cardiac arrest (CA). This study examines electrocorticogram (ECoG) activity and coherence of the dying brain during asphyxial CA. Male Wistar rats (n = 16) were induced with isoflurane anesthesia, which was washed out before asphyxial CA. Mean phase coherence and ECoG power were compared during different stages of the asphyxial period to assess potential neural correlates of consciousness. After asphyxia, the ECoG progressed through four distinct stages (asphyxial stages 1-4 [AS1-4]), including a transient period of near-electrocerebral silence lasting several seconds (AS3). Electrocerebral silence (AS4) occurred within 1 min of the start of asphyxia, and pulseless electrical activity followed the start of AS4 by 1-2 min. AS3 was linked to a significant increase in frontal coherence between the left and right motor cortices (p silence contains distinctive neural activity. Specifically, the burst in frontal coherence and posterior shift of ECoG power that we find during this period immediately preceding CA may be a neural correlate of conscious processing.

  18. 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.

  19. 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

    2015-02-01

    Full Text Available Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR 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, the flagship disaster mitigation program of the Department of Science and Technology (DOST, Government of the Philippines, 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 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.

  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 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. Twelve-year cyclic surging episode at Donjek Glacier in Yukon, Canada

    Science.gov (United States)

    Furuya, M.; Abe, T.; Sakakibara, D.

    2015-12-01

    Surge-type glaciers exhibit several-fold to orders-of-magnitude speed-up during the short active phase, resulting in km-scale terminus advance. Although there are many surge-type glaciers near the border of Alaska and the Yukon, the generation mechanisms remain uncertain because of limited and few continuous observations. To better understand the surge dynamics and predict the next event, it is essential to examine the entire surge cycles. Here we use Landsat optical imageries to reveal the long-term evolutions, and report three surging episodes at Donjek Glacier in Yukon, Canada. Using the Landsat images, we found three surging events in 1989, 2001, and 2013. In the 2001 event, the surface speed significantly increased by up to 4.5 m/d; during the quiescent phases it was ~0.5 m/d at the terminus. While the duration of active phase is about 4~5 and 2~3 year in the 2001 and 2013 events, the period in the 1989 event is unclear because of the lack of high temporal resolution data. Remarkably, the surging area is limited to the ~20-km section from the terminus instead of the entire glacier. Moreover, we examined the terminus area changes from 1975 to 2014. Although the area has been secularly decreasing probably due to the tread of global warming, it has also revealed four significant fluctuations during the nearly forty years. Comparing the speed and the area changes, the three speed-up events correspond to the terminus area fluctuations with a few time lags. It turns out that the surge event has been quite regularly repeating every twelve years. Although the behavior is rather similar to that in Svalbard glaciers in terms of maximum speed and unclear initiation season, the recurrence interval is much shorter than other nearby surges. Considering that the surge events seem to have initiated around significantly narrower area than upstream, the strong valley constriction may control the regularity as well as the twelve-year recurrence time.

  2. The eSurge-Venice project: altimeter and scatterometer satellite data to improve the storm surge forecasting in the city of Venice

    Science.gov (United States)

    Zecchetto, Stefano; De Biasio, Francesco; Umgiesser, Georg; Bajo, Marco; Vignudelli, Stefano; Papa, Alvise; Donlon, Craig; Bellafiore, Debora

    2013-04-01

    On the framework of the Data User Element (DUE) program, the European Space Agency is funding a project to use altimeter Total Water Level Envelope (TWLE) and scatterometer wind data to improve the storm surge forecasting in the Adriatic Sea and in the city of Venice. The project will: a) Select a number of Storm Surge Events occurred in the Venice lagoon in the period 1999-present day b) Provide the available satellite Earth Observation (EO) data related to the Storm Surge Events, mainly satellite winds and altimeter data, as well as all the available in-situ data and model forecasts c) Provide a demonstration Near Real Time service of EO data products and services in support of operational and experimental forecasting and warning services d) Run a number of re-analysis cases, both for historical and contemporary storm surge events, to demonstrate the usefulness of EO data The re-analysis experiments, based on hindcasts performed by the finite element 2-D oceanographic model SHYFEM (https://sites.google.com/site/shyfem/), will 1. use different forcing wind fields (calibrated and not calibrated with satellite wind data) 2. use Storm Surge Model initial conditions determined from altimeter TWLE data. The experience gained working with scatterometer and Numerical Weather Prediction (NWP) winds in the Adriatic Sea tells us that the bias NWP-Scatt wind is negative and spatially and temporally not uniform. In particular, a well established point is that the bias is higher close to coasts then offshore. Therefore, NWP wind speed calibration will be carried out on each single grid point in the Adriatic Sea domain over the period of a Storm Surge Event, taking into account of existing published methods. Point #2 considers two different methodologies to be used in re-analysis tests. One is based on the use of the TWLE values from altimeter data in the Storm Surge Model (SSM), applying data assimilation methodologies and trying to optimize the initial conditions of the

  3. Resuscitation, prolonged cardiac arrest, and an automated chest compression device

    DEFF Research Database (Denmark)

    Risom, Martin; Jørgensen, Henrik; Rasmussen, Lars S

    2010-01-01

    The European Resuscitation Council's 2005 guidelines for cardiopulmonary resuscitation (CPR) emphasize the delivery of uninterrupted chest compressions of adequate depth during cardiac arrest.......The European Resuscitation Council's 2005 guidelines for cardiopulmonary resuscitation (CPR) emphasize the delivery of uninterrupted chest compressions of adequate depth during cardiac arrest....

  4. Cardiac catheterization is underutilized after in-hospital cardiac arrest.

    Science.gov (United States)

    Merchant, Raina M; Abella, Benjamin S; Khan, Monica; Huang, Kuang-Ning; Beiser, David G; Neumar, Robert W; Carr, Brendan G; Becker, Lance B; Vanden Hoek, Terry L

    2008-12-01

    Indications for immediate cardiac catheterization in cardiac arrest survivors without ST elevation myocardial infarction (STEMI) are uncertain as electrocardiographic and clinical criteria may be challenging to interpret in this population. We sought to evaluate rates of early catheterization after in-hospital ventricular fibrillation (VF) arrest and the association with survival. Using a billing database we retrospectively identified cases with an ICD-9 code of cardiac arrest (427.5) or VF (427.41). Discharge summaries were reviewed to identify in-hospital VF arrests. Rates of catheterization on the day of arrest were determined by identifying billing charges. Unadjusted analyses were performed using Chi-square, and adjusted analyses were performed using logistic regression. One hundred and ten in-hospital VF arrest survivors were included in the analysis. Cardiac catheterization was performed immediately or within 1 day of arrest in 27% (30/110) of patients and of these patients, 57% (17/30) successfully received percutaneous coronary intervention. Of those who received cardiac catheterization the indication for the procedure was STEMI or new left bundle branch block (LBBB) in 43% (13/30). Therefore, in the absence of standard ECG data suggesting acute myocardial infarction, 57% (17/30) received angiography. Patients receiving cardiac catheterization were more likely to survive than those who did not receive catheterization (80% vs. 54%, psurvival. Future recommendations need to be established to guide clinicians on which arrest survivors might benefit from immediate catheterization.

  5. Arrested puberty associated with a Sertoli-Leydig cell tumor.

    Science.gov (United States)

    Kelly, A C; Feinman, M A; Husami, N

    1985-06-01

    Androgen-producing ovarian tumors are rarely recognized as a cause of delayed or arrested puberty, despite their frequent association with secondary amenorrhea in the older patient. A case is discussed of a Sertoli-Leydig cell tumor in an 18-year-old girl resulting in arrest of breast development and primary amenorrhea.

  6. Evolution of the dragonfly head-arresting system

    Science.gov (United States)

    Gorb, S. N.

    1999-01-01

    The arrester or fixation system of the head in adult Odonata is unique among arthropods. This system involves the organs of two body segments: the head and the neck. It consists of a skeleton–muscle apparatus that sets the arrester parts in motion. The parts comprise formations covered with complicated microstructures: fields of microtrichia on the rear surface of the head and post-cervical sclerites of the neck. The arrester immobilizes the head during feeding or when the dragonfly is in tandem flight. Thus, it may serve as an adaptation to save the head from violent mechanical disturbance and to stabilize gaze in a variety of behavioural situations. This study shows the evolutionary trend of the arrester in the order Odonata by using scanning electron microscopy and measurements of arrester structures in 227 species from 26 odonate families. The arrester design occurring in the Epiophlebiidae, Gomphidae, Neopetaliidae, Petaluridae and Chlorogomphinae is suggested to be the basic one. Two convergent pathways of head-arrester evolution among Zygoptera and Anisoptera are proposed. The possible functional significance of the arrester system is discussed.

  7. Predictive Value of Brain Arrest Neurological Outcome Scale (BrANOS) on Mortality and Morbidity After Cardiac Arrest

    Science.gov (United States)

    Şahutoğlu, Cengiz; Uyar, Mehmet; Demirağ, Kubilay; İsayev, Hasan; Moral, Ali Reşat

    2016-01-01

    Objective There are several prediction scales and parameters for prognosis after a cardiac arrest. One of these scales is the brain arrest neurological outcome scale (BrANOS), which consists of duration of cardiac arrest, Glasgow Coma Scale score and Hounsfield unit measured on cranial computed tomography (CT) scan. The objective of this study is to investigate the effectiveness of BrANOS on predicting the mortality and disability after a cardiac arrest. Methods We retrospectively investigated cardiac arrest patients who were hospitalized in our intensive care unit (ICU) within a 3-year period. Inclusion criteria were age over 18 years old, survival of more than 24 hours after cardiac arrest and availability of cranial CT. We recorded the age, sex, diagnosis, duration of cardiac arrest and hospital stay, mortality, Glasgow Outcome Score (GOS) and BrANOS score. The primary endpoint of the study was to establish the relationship between mortality and BrANOS score in patients who survived for more than 24 hours after a cardiac arrest. The secondary endpoint of the study was to determine the 2-year life expectancy and GOS after cardiac arrest. Results The mean age of the patients was 57±17 years (33 females, 67 males). ICU mortality rate was 57%. The BrANOS mean score was 10.3±3.2. There was a significant difference between survivors and non-survivors in terms of the BrANOS score (8.8±3.2 vs. 11.6±2.7; p14 predicted death with 100% accuracy. All the patients without disability had a BrANOS score of <10. The BrANOS score also correlated well with GOS (p<0.001). The 2-year life expectancy rate was 31% in patients who survived more than 24 hours after a cardiac arrest. Conclusion In this study, we demonstrated that BrANOS provided reliable data for prognostic evaluation after a cardiac arrest. PMID:28058140

  8. Association of National Initiatives to Improve Cardiac Arrest Management With Rates of Bystander Intervention and Patient Survival After Out-of-Hospital Cardiac Arrest

    DEFF Research Database (Denmark)

    Wissenberg, Mads; Lippert, Freddy K; Folke, Fredrik

    2013-01-01

    resuscitation was attempted were identified between 2001 and 2010 in the nationwide Danish Cardiac Arrest Registry. Of 29 111 patients with cardiac arrest, we excluded those with presumed noncardiac cause of arrest (n = 7390) and those with cardiac arrests witnessed by emergency medical services personnel (n...

  9. Structural arrest in an ideal gas.

    Science.gov (United States)

    van Ketel, Willem; Das, Chinmay; Frenkel, Daan

    2005-04-08

    We report a molecular dynamics study of a simple model system that has the static properties of an ideal gas, yet exhibits nontrivial "glassy" dynamics behavior at high densities. The constituent molecules of this system are constructs of three infinitely thin hard rods of length L, rigidly joined at their midpoints. The crosses have random but fixed orientation. The static properties of this system are those of an ideal gas, and its collision frequency can be computed analytically. For number densities NL(3)/V>1, the single-particle diffusivity goes to zero. As the system is completely structureless, standard mode-coupling theory cannot describe the observed structural arrest. Nevertheless, the system exhibits many dynamical features that appear to be mode-coupling-like. All high-density incoherent intermediate scattering functions collapse onto master curves that depend only on the wave vector.

  10. Mapping Risks Due To Storm Surges Within The Coastal Zone

    Science.gov (United States)

    Mai, S.; Zimmermann, C.

    The coast protection at the Wadden Sea coastline of Lower Saxony, Germany, is mainly guaranteed by sea dikes. In case of a failure of these dikes a total area of approx. 7.130 km2 is endangered from inundation. Besides that approx. 1.3 million people and economic values of 150 billion Euro are at risk. The consequences of dike failure show a large spatial variability. However today's design of sea dikes does not take into account the spatial variability, i.e. coastal areas with high losses in case of dike failure are not protected better than those with low. In order to improve this sit- uation a scheme for risk analysis was developed and applied at the estuaries Jade and Weser including the cities Wilhelmshaven, Bremerhaven, Bremen and Cuxhaven. The scheme of risk analysis comprises on the one hand a calculation of the probability of dike failure and a determination of the area flooded in case of dike breaching and on the other hand a register of all values, i.e. houses, industrial estates and infrastructure, within the hinterland. The different steps are integrated and linked to a Geographical Information System GIS using ARCVIEW. Within the developed design scheme failure of sea dikes is related to wave overtop- ping. Therefore the probability of failure is determined from the joined probability of tidal high water-levels and waves. The statistics of latter are calculated from the wind statistics using the numerical wave model SWAN. The time dependent flooding process after dike breaches is calculated with the numer- ical model MIKE 21 HD providing information on the depth, velocity and duration of the inundation. The sensitivity of the calculations of the inundation characteristics with respect to the width of the dike breach, the surface roughness and the character- istics of the storm surge is evaluated. The inundation depth and speed is used to estimate the damage factor, i.e. the ratio of the expected loss after inundation and the maximum possible loss. The

  11. Morning blood pressure surge: the reliability of different definitions.

    Science.gov (United States)

    Stergiou, George S; Mastorantonakis, Stylianos E; Roussias, Leonidas G

    2008-08-01

    Preliminary evidence suggests that the morning surge (MS) in blood pressure (BP) is an independent predictor of cerebrovascular disease. However, the optimal definition of MS is uncertain. To compare the reproducibility of several MS definitions used in the literature, 132 untreated hypertensives were assessed with ambulatory BP monitoring twice, 2 weeks apart. Five MS definitions were compared. MS-1: the average BP of the first hour after rising minus the average BP of the first hour before rising; MS-2: BP 2 h after rising minus that of 2 h before rising; MS-3: BP 3 h after rising minus that of 3 h before rising; MS-4: BP 2 h after rising minus the average BP during sleep; MS-5: BP 2 h after rising minus the average BP of 3 consecutive readings, centered on the lowest reading during sleep. The reproducibility of each MS definition was assessed using the concordance correlation coefficient (CCC), the standard deviation of differences (SDD) and the coefficient of variation (CV) between repeated MS assessments, and the agreement in detecting "surgers," defined as subjects at the top quartile (Q4) of the MS distribution. CCCs were 0.20/0.30, 0.43/0.45, 0.53/0.51, 0.51/0.47, and 0.46/0.48 (systolic/diastolic) for MS-1 to MS-5 respectively; SDDs were 14.3/11.4, 12.1/9.9, 11.2/9.5, 10.3/8.2, and 11.9/9.8, respectively; CVs were 0.49/0.57, 0.44/0.39, 0.37/0.35, 0.36/0.31, and 0.27/0.24, respectively; and the agreement in detecting "surgers" was 69%/70%, 71%/76%, 75%/75%, 81%/83%, and 74%/75%, with kappa of 0.18/0.20, 0.23/0.36, 0.33/0.33, 0.49/0.53 and 0.29/0.31, respectively. There are important differences in the reproducibility of MS calculated by different methods. MS4 appears to provide the most reproducible definition of MS.

  12. Selection of gonadotrophin surge attenuating factor phage antibodies by bioassay

    Directory of Open Access Journals (Sweden)

    Mason Helen D

    2005-09-01

    Full Text Available Abstract Background We aimed to combine the generation of "artificial" antibodies with a rat pituitary bioassay as a new strategy to overcome 20 years of difficulties in the purification of gonadotrophin surge-attenuating factor (GnSAF. Methods A synthetic single-chain antibody (Tomlinson J phage display library was bio-panned with partially purified GnSAF produced by cultured human granulosa/luteal cells. The initial screening with a simple binding immunoassay resulted in 8 clones that were further screened using our in-vitro rat monolayer bioassay for GnSAF. Initially the antibodies were screened as pooled phage forms and subsequently as individual, soluble, single-chain antibody (scAbs forms. Then, in order to improve the stability of the scAbs for immunopurification purposes, and to widen the range of labelled secondary antibodies available, these were engineered into full-length human immunoglobulins. The immunoglobulin with the highest affinity for GnSAF and a previously described rat anti-GnSAF polyclonal antiserum was then used to immunopurify bioactive GnSAF protein. The two purified preparations were electrophoresed on 1-D gels and on 7 cm 2-D gels (pH 4–7. The candidate GnSAF protein bands and spots were then excised for peptide mass mapping. Results Three of the scAbs recognised GnSAF bioactivity and subsequently one clone of the purified scAb-derived immunoglobulin demonstrated high affinity for GnSAF bioactivity, also binding the molecule in such as way as to block its bioactivity. When used for repeated immunopurification cycles and then Western blot, this antibody enabled the isolation of a GnSAF-bioactive protein band at around 66 kDa. Similar results were achieved using the rat anti-GnSAF polyclonal antiserum. The main candidate molecules identified from the immunopurified material by excision of 2-D gel protein spots was human serum albumin precursor and variants. Conclusion This study demonstrates that the combination of

  13. Out-of-Hospital Cardiac Arrest in Denmark

    DEFF Research Database (Denmark)

    Wissenberg Jørgensen, Mads

    challenges, due to the victim’s physical location, which brings an inherent risk of delay (or altogether absence) of recognition and treatment of cardiac arrest. A low frequency of bystander cardiopulmonary resuscitation and low 30-day survival after out-of-hospital cardiac arrest were identified nearly ten......BACK COVER TEXT Cardiac arrest is an emergency medical condition characterized by the cessation of cardiac mechanical activity; without immediate and decisive treatment, a victim’s chances of survival are minimal. Out-of-hospital cardiac arrest is a particular arrest subgroup that poses additional...... years ago in Denmark. These findings led to several national initiatives to strengthen bystander resuscitation attempts and advance care. Despite these nationwide efforts, it was unknown prior to this project whether these efforts resulted in changes in resuscitation attempts by bystanders and changes...

  14. Sublingual Microcirculation is Impaired in Post-cardiac Arrest Patients

    DEFF Research Database (Denmark)

    G. Omar, Yasser; Massey, Michael; Wiuff Andersen, Lars;

    2013-01-01

    AIM: We hypothesized that microcirculatory dysfunction, similar to that seen in sepsis, occurs in post-cardiac arrest patients and that better microcirculatory flow will be associated with improved outcome. We also assessed the association between microcirculatory dysfunction and inflammatory...... markers in the post-cardiac arrest state. METHODS: We prospectively evaluated the sublingual microcirculation in post-cardiac arrest patients, severe sepsis/septic shock patients, and healthy control patients using Sidestream Darkfield microscopy. Microcirculatory flow was assessed using...... the microcirculation flow index (MFI) at 6 and 24h in the cardiac arrest patients, and within 6h of emergency department admission in the sepsis and control patients. RESULTS: We evaluated 30 post-cardiac arrest patients, 16 severe sepsis/septic shock patients, and 9 healthy control patients. Sublingual...

  15. The Business Value of Online Monitoring System for Arrester%避雷器在线监测系统的商业价值

    Institute of Scientific and Technical Information of China (English)

    季倩

    2013-01-01

    金属氧化物避雷器,简称MOA,广泛应用于各大电力系统对相关设备进行过电压保护,避免设备遭受雷击等损害。为确保相关系统稳定运行,必须对MOA本身进行状态监测以确保MOA正常运行。目前各大电力系统对于MOA的监测方式仍然比较落后,避雷器在线监测系统的商业潜在价值非常大,值得相关人员进行研发推广。%Metal oxide surge arrester(referred to MOA)have been used in various power system to prevent overvoltage and avoid equipment’s damage from lightning.We must monitor the working status of MOA to make sure MOA works in a normal condition so that underlying system can work normally.At present the methods for monitoring the MOA in our power system is still relatively backward,so remote monitoring system for Arrest-er is full of commercial potential value,and is worth to developing and promoting for related people.

  16. Mitigation of hurricane storm surge impacts: Modeling scenarios over wide continental shelves

    Science.gov (United States)

    Lima Rego, Joao; Li, Chunyan

    2010-05-01

    The improvement of present understanding of surge dynamics over wide and shallow shelves is vital for the improvement of our ability to forecast storm surge impacts to coastal regions, particularly the low-lying land areas that are most vulnerable to hurricane flooding (e.g. the Northern Gulf of Mexico, coastal Bangladesh, the Southeast China sea). Given the increase of global sea-surface temperature, both the total number and proportion of intense tropical cyclones have increased notably since 1970 (Emanuel, 2005; Nature). Therefore, more intense hurricanes may hit densely populated coastal regions, and this problem may be aggravated by the prospect of accelerated sea-level rise in the 21st century. This presentation offers a review of recent work on hurricane-induced storm surge. The finite-volume coastal ocean model ("FVCOM", by Chen et al., 2003; J. Atmos. Ocean Tech.) was applied to the storm surge induced by Hurricanes Rita and Ike along the coasts of Louisiana and Texas in 2005 and 2008, respectively, to study coastal storm surge dynamics. The sensitivity analysis of Rego and Li (2009; Geophys. Res. Lett.) demonstrated how stronger, wider or faster tropical cyclones would affect coastal flooding. Li, Weeks and Rego (2009; Geophys. Res. Lett) looked into how hurricane flooding and receding dynamics differ, concluding that the overland flow in the latter stage is of considerable importance. Rego and Li (2010; J. Geophys. Res.) showed how extreme events may result of a combination of non-extreme factors, by studying the nonlinear interaction of tide and hurricane surge. The ability of models to reproduce these extreme events and to proactive plan for damage reduction is covered in Rego and Li's (2010; J. Marine Syst.) study of how barrier island systems protect coastal bays from offshore surge propagation. Here we combine these results for a wider perspective on how hurricane flooding could be mitigated under changing conditions.

  17. Studies on scaled models for gas entrainment in the surge tank of LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Ramdasu, D.; Shivakumar, N.S.; Padmakumar, G.; Anand Babu, C.; Vaidyanathan, G. [Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Rammohan, S.; Sreekala, S.K.; Manikandan, S.; Saseendran, S. [Fluid Control Research Institute, Palghat (India)

    2007-07-01

    This paper presents the studies carried out in the different scale models of Surge tank used in the secondary circuit of Liquid metal fast breeder reactor (LMFBR). Surge tank acquires importance because of its ability to take care of pressure surges in case of a sodium water reaction in Steam Generators (SG). The blanket of argon cover gas above the sodium free surface in the surge tank acts as a cushion for the surges. At the same time, argon gas is a source of entrainment into the sodium which is undesirable from the consideration of effective heat transfer in Inter mediate Heat Exchanger and SG, cavitation in pumps and operational problems of continuous feed and bleed of cover gas, thus leading to unfavourable reactor operating conditions. To investigate the phenomenon of gas entrainment in surge tank, hydraulic experiments were conducted in water using 1/38, 1/32, 1/22 and 1/12 scale models with Froude similarity. The minimum height of liquid column required to avoid gas entrainment was determined using different types of internal devices. Experiments were carried out in the 5/8 scale model to confirm the results of the smaller scale models. It was found that free surface height to avoid gas entrainment varies for different scale models. The combination of Pepper pot with ring plate was found to be the most effective in avoiding gas entrainment at H/D equals 1.28 where H is the height of liquid column in the tank from tank bottom and D is the inner diameter of surge tank.

  18. 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.

  19. Investigating changes in basal conditions of Variegated Glacier prior and during its 1982–1983 surge

    Directory of Open Access Journals (Sweden)

    O. Gagliardini

    2011-05-01

    Full Text Available The 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-year dataset, consisting in surface topography and surface velocity observations along a flow line for 25 dates, we have reconstructed the evolution of the basal conditions prior 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 Gudmundson (2010. This method is here slightly modified by incorporating a regularisation term in the cost function to avoid short wave length changes in the friction parameter. Our results indicate that dramatic changes in the basal conditions occurred between 1973 to 1983. Prior to the surge, periodical 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. It confirms 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 infer realistic scenarios for the hydrological history leading to the occurrence of a surge.

  20. Tsivat Basin conduit system persists through two surges, Bering Piedmont Glacier, Alaska

    Science.gov (United States)

    Fleisher, P.J.; Cadwell, D.H.; Muller, E.H.

    1998-01-01

    The 1993-1995 surge of Bering Glacier, Alaska, occurred in two distinct phases. Phase 1 of the surge began on the eastern sector in July, 1993 and ended in July, 1994 after a powerful outburst of subglacial meltwater into Tsivat Lake basin on the north side of Weeping Peat Island. Within days, jokulhlaup discharge built a 1.5 km2 delta of ice blocks (25-30 m) buried in outwash. By late October 1994, discharge temporarily shifted to a vent on Weeping Peat Island, where a second smaller outburst dissected the island and built two new sandar. During phase 2, which began in spring 1995 and ended within five months, continuous discharge issued from several vents along the ice front on Weeping Peat Island before returining to the Tsivat Basin. Surge related changes include a five- to six-fold increase in meltwater turbidity; the redirection of supercooled water in two ice-contact lakes; and an increase in the rate of glaciolacustrine sedimentation. US Geological Survey aerial photos by Austin Post show large ice blocks in braided channels indicating excessive subglacial discharge in a similar position adjacent to Weeping Peat Island during the 1966-1967 surge. During the subsequent three decades of retreat, the location of ice-marginal, subglacial discharge vents remained aligned on a linear trend that describes the position of a persistent subglacial conduit system. The presence of a major conduit system, possibly stabilized by subglacial bedrock topography, is suggested by: 1) high-level subglacial meltwater venting along the northern side of Weeping Peat Island during the 1966-1967 surge, 2) persistent low-level discharge between surges, and 3) the recurrence of localizing meltwater outbursts associated with both phases of the 1993-1005 surge.

  1. 广东地区变电站出线断路器侵入波过电压实时数字仿真分析%Realtime Digital Simulation of Lightning Surge Intrusion on Outlet Circuit Breakers of Substations in Guangdong Region

    Institute of Scientific and Technical Information of China (English)

    彭向阳; 姚森敬; 郭婷; 周文俊

    2012-01-01

    General situation of substation outlet circuit breaker faults caused by lightning surge intrusion occurred in Guangdong region before the installation of outlet arrester is described, and it is clarified that the lightning surge intrusion protection for outlet circuit breakers during its reclosure must be reinforced, i.e., outlet arresters must be installed in front of outlet circuit breakers. Utilizing real-time" digital simulator (RTDS), the overvoltage caused by lightning surge intrusion during the reclosure of outlet circuit breaker is simulated, and the effect of enhancing insulation level of transmission line and the protection result of adding outlet arresters are evaluated as well. Simulation results show that after outlet arrester is installed, although the insulation level of transmission line is strengthened considerably, dangerous lightning surge intrusion will not appear on outlet circuit breaker, thus the operating condition of lightning protection for substation can be effectively improved.%介绍广东地区变电站未安装出线避雷器前雷电侵入波事故概况,明确了必须加强出线断路器重合闸期间的侵入波保护,即应安装出线断路器前置避雷器。利用实时数字仿真器(real.timedigitalsimulator,RTDS)分析变电站出线断路器开断期间雷电侵入波过电压,并对加强线路绝缘的影响以及出线避雷器的保护效果进行评估。计算结果表明:变电站装设出线避雷器后,即使大幅提高输电线路绝缘水平,也不会在出线断路器产生危险的雷电侵入波过电压,能有效地改善变电站防雷运行工况。

  2. 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.

  3. A probabilistic storm surge risk model for the German North Sea and Baltic Sea coast

    Science.gov (United States)

    Grabbert, Jan-Henrik; Reiner, Andreas; Deepen, Jan; Rodda, Harvey; Mai, Stephan; Pfeifer, Dietmar

    2010-05-01

    The German North Sea coast is highly exposed to storm surges. Due to its concave bay-like shape mainly orientated to the North-West, cyclones from Western, North-Western and Northern directions together with astronomical tide cause storm surges accumulating the water in the German bight. Due to the existence of widespread low-lying areas (below 5m above mean sea level) behind the defenses, large areas including large economic values are exposed to coastal flooding including cities like Hamburg or Bremen. The occurrence of extreme storm surges in the past like e.g. in 1962 taking about 300 lives and causing widespread flooding and 1976 raised the awareness and led to a redesign of the coastal defenses which provide a good level of protection for today's conditions. Never the less the risk of flooding exists. Moreover an amplification of storm surge risk can be expected under the influence of climate change. The Baltic Sea coast is also exposed to storm surges, which are caused by other meteorological patterns. The influence of the astronomical tide is quite low instead high water levels are induced by strong winds only. Since the exceptional extreme event in 1872 storm surge hazard has been more or less forgotten. Although such an event is very unlikely to happen, it is not impossible. Storm surge risk is currently (almost) non-insurable in Germany. The potential risk is difficult to quantify as there are almost no historical losses available. Also premiums are difficult to assess. Therefore a new storm surge risk model is being developed to provide a basis for a probabilistic quantification of potential losses from coastal inundation. The model is funded by the GDV (German Insurance Association) and is planned to be used within the German insurance sector. Results might be used for a discussion of insurance cover for storm surge. The model consists of a probabilistic event driven hazard and a vulnerability module, furthermore an exposure interface and a financial

  4. Impacts of land cover changes on hurricane storm surge in the lower Chesapeake Bay

    Science.gov (United States)

    Denton, M.; Lawler, S.; Ferreira, C.

    2013-12-01

    The Chesapeake Bay is the largest estuary in the United States with more than 150 rivers draining into the bay's tidal wetlands. Coastal wetlands and vegetation play an important role in shaping the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge. In this way coastal wetlands act as a natural barrier to inland flooding, particularly against less intense storms. Threats to wetlands come from both land development (residential or commercial/industrial) and sea level rise. The lower region of the Chesapeake Bay near its outlet is especially vulnerable to flooding from Atlantic storm surge brought in by hurricanes, tropical storms and nor'easters (e.g., hurricanes Isabel [2003] and Sandy [2012]). This region is also intensely developed with nearly 1.7 million residents within the greater Hampton Roads metropolitan area. Anthropogenic changes to land cover in the lower bay can directly impact basin drainage and storm surge propagation with impacts reaching beyond the immediate coastal zone to affect flooding in inland areas. While construction of seawall barriers around population centers may provide storm surge protection to a specifically defined area, these barriers deflect storm surge rather than attenuate it, underscoring the importance of wetlands. To analyze these impacts a framework was developed combining numerical simulations with a detailed hydrodynamic characterization of flow through coastal wetland areas. Storm surges were calculated using a hydrodynamic model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using the FEMA region 3 unstructured mesh (2.3 million nodes) under a High Performance Computing (HPC) environment. Multiple model simulations were performed using historical hurricanes data and hypothetical storms to compare the predicted storm surge inundation with various levels of wetland reduction and/or beach hardening. These data were combined and overlaid

  5. Metal Oxide Surge Arrester Typical Defect Analysis%金属氧化物避雷器典型缺陷分析

    Institute of Scientific and Technical Information of China (English)

    王鹤许; 刘海峰; 李俊卿

    2012-01-01

    介绍金属氧化物避雷器的结构和检测方法,分析金属氧化物避雷器运行中的典型缺陷,认为电阻片受潮和老化是造成金属氧化物避雷器缺陷的主要原因,并提出减少避雷器故障的建议.

  6. 无间隙金属氧化物避雷器带电监测%Power-on Monitoring of Metal-oxide Surge Arrester without Gaps

    Institute of Scientific and Technical Information of China (English)

    赵雪林; 林蒙丹

    2007-01-01

    以无间隙金属氧化物避雷器的技术条件为依据,分析了停电检测的局限性与带电监测测量的可行性,提出MOA正常运行时,以带电试验为主,在MOA的带电试验测量数据出现异常时,则采用停电测试和带电测试相结合的方法,并以停电试验数据作为MOA是否继续投运的最终判断依据.

  7. Application and Standards of Metal Oxide Surge Arresters with Gaps%有间隙金属氧化物避雷器的应用与标准

    Institute of Scientific and Technical Information of China (English)

    张家骞

    2005-01-01

    有间隙金属氧化物避雷器由于其串联间隙的隔离与分压作用,大大降低了对氧化锌电阻片性能上的要求.相对早期的无间隙产品,运行可靠性高,成本优势突现.本文列出了有间隙金属氧化物避雷器的国内最新标准(报批稿)所规定的技术参数,并针对新标准的相关问题进行了解释.选用有间隙金属氧化物避雷器时,除了看残压外还应兼顾产品的冲击放电伏一秒特性,且以数值相对差的一种视作该产品的保护特性.

  8. 日本氧化锌避雷器的发展动向%Development Trends of Metal Oxide Surge Arresters in Japan

    Institute of Scientific and Technical Information of China (English)

    王兰义

    1999-01-01

    对日本金属氧化物避雷器主要生产企业的氧化锌避雷器及氧化锌非线性电阻片的水平和发展方向进行了综述,指出了今后金属氧化物避雷器及氧化锌电阻片的发展方向.这对国内氧化锌避雷器及氧化锌电阻片的生产厂家来说,具有一定的指导意义.

  9. 避雷器设计口诀和焦点问题探讨%Discussion of Design Mnemonics and Focal Question of Surge Arrester

    Institute of Scientific and Technical Information of China (English)

    车文俊; 李凡

    2011-01-01

    在避雷器参数与选用等相关铺垫的基础上,提出并剖析经实践总结得出的避雷器设计口诀.探讨特/超高压和直流等高大瓷套型避雷器的人工污秽试验、较高电压等级避雷器监测器的压力释放试验和门槛动作电流等焦点问题.提出选用避雷器时应注重性价比.

  10. Swift snowmelt and floods (lahars) caused by great pyroclastic surge at Mount St Helens volcano, Washington, 18 May 1980

    Science.gov (United States)

    Waitt, R.B.

    1989-01-01

    The initial explosions at Mount St. Helens, Washington, on the moring of 18 May 1980 developed into a huge pyroclastic surge that generated catastrophic floods off the east and west flanks of the volcano. Near-source surge deposits on the east and west were lithic, sorted, lacking in accretionary lapilli and vesiculated ash, not plastered against upright obstacles, and hot enough to char wood - all attributes of dry pyroclastic surge. Material deposited at the surge base on steep slopes near the volcano transformed into high-concentration lithic pyroclastic flows whose deposits contain charred wood and other features indicating that these flows were hot and dry. Stratigraphy shows that even the tail of the surge had passed the east and west volcano flanks before the geomorphically distinct floods (lahars) arrived. This field evidence undermines hypotheses that the turbulent surge was itself wet and that its heavy components segregated out to transform directly into lahars. Nor is there evidence that meters-thick snow-slab avalanches intimately mixed with the surge to form the floods. The floods must have instead originated by swift snowmelt at the base of a hot and relatively dry turbulent surge. Impacting hot pyroclasts probably transferred downslope momentum to the snow surface and churned snow grains into the surge base. Melting snow and accumulating hot surge debris may have moved initially as thousands of small thin slushflows. As these flows removed the surface snow and pyroclasts, newly uncovered snow was partly melted by the turbulent surge base; this and accumulating hot surge debris in turn began flowing, a self-sustaining process feeding the initial flows. The flows thus grew swiftly over tens of seconds and united downslope into great slushy ejecta-laden sheetfloods. Gravity accelerated the floods to more than 100 km/h as they swept down and off the volcano flanks while the snow component melted to form great debris-rich floods (lahars) channeled into

  11. Mass Balance Evolution of Black Rapids Glacier, Alaska, 1980–2100, and Its Implications for Surge Recurrence

    OpenAIRE

    Christian Kienholz; Regine Hock; Martin Truffer; Peter Bieniek; Richard Lader

    2017-01-01

    Surge-type Black Rapids Glacier, Alaska, has undergone strong retreat since it last surged in 1936–1937. To assess its evolution during the late Twentieth and Twenty-first centuries and determine potential implications for surge likelihood, we run a simplified glacier model over the periods 1980–2015 (hindcasting) and 2015–2100 (forecasting). The model is forced by daily temperature and precipitation fields, with downscaled reanalysis data used for the hindcasting. A constant climate scenario...

  12. 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.

  13. Numerical study of flow fluctuation attenuation performance of a surge tank

    Institute of Scientific and Technical Information of China (English)

    郭兰兰; 刘正刚; 耿介; 李东; 杜广生

    2013-01-01

    The surge tank plays an important role in ensuring the stability of a water flow standard device. To study the influence of the structure and the working conditions on the regulator performance of a surge tank, a three-dimensional model, including a surge tank, the pipeline and the water tank is built, and the VOF model in the Fluent software is used to simulate the two-phase pulsatile flow in the surge tank. The inlet flow pulsation is defined by the User Defined Functions (UDF), and the outlet flow is set to be a free jet. By calculating the flow fluctuation coefficient of the variation under different flow conditions, the influences of the pulse frequency, the initial water level height and the baffle plate structure on the flow stability are analyzed. It is shown that the surge tank has a good attenuation effect on high-frequency pulsations, there is an optimal initial water level to suppress the fluctuations, the round holes of the baffle should ensure a certain circulation area with the bore diameter small enough to have the necessary damping effect.

  14. The optimization of design parameters for surge relief valve for pipeline systems

    Science.gov (United States)

    Kim, Hyunjun; Hur, Jisung; Kim, Sanghyun

    2017-06-01

    Surge is an abnormal pressure which induced by rapid changes of flow rate in pipeline systems. In order to protect pipeline system from the surge pressure, various hydraulic devices have been developed. Surge-relief valve(SRV) is one of the widely applied devices to control surge due to its feasibility in application, efficiency and cost-effectiveness. SRV is designed to automatically open under abnormal pressure and discharge the flow and makes pressure of the system drop to the allowable level. The performance of the SRV is influenced by hydraulics. According to previous studies, there are several affecting factors which determine performance of the PRV such as design parameters (e.g. size of the valve), system parameters (e.g. number of the valves and location of the valve), and operation parameters (e.g. set point and operation time). Therefore, the systematic consideration for factors affecting performance of SRV is required for the proper installation of SRV in the system. In this study, methodology for finding optimum parameters of the SRV is explored through the integration of Genetic Algorithm(GA) into surge analysis.

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

    Science.gov (United States)

    Bastidas, Luis A.; Knighton, James; Kline, Shaun W.

    2016-09-01

    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 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.

  16. Changes in the Earth's largest surge glacier system from satellite and airborne altimetry and imagery

    Science.gov (United States)

    Trantow, T.; Herzfeld, U. C.

    2015-12-01

    The Bering-Bagley Glacier System (BBGS), Alaska, one of the largest ice systems outside of Greenland and Antarctica, has recently surged (2011-2013), providing a rare opportunity to study the surge phenomenon in a large and complex system. Understanding fast-flowing glaciers and accelerations in ice flow, of which surging is one type, is critical to understanding changes in the cryosphere and ultimately changes in sea level. It is important to distinguish between types of accelerations and their consequences, especially between reversible or quasi-cyclic and irreversible forms of glacial acceleration, but current icesheet models treat all accelerating ice identically. Additionally, the surge provides an exceptional opportunity to study the influence of surface roughness and water content on return signals of altimeter systems. In this presentation, we analyze radar and laser altimeter data from CryoSat-2, NASA's Operation IceBridge (OIB), the ICESat Geoscience Laser Altimeter System (GLAS), ICESat-2's predecessor the Multiple Altimeter Beam Experimental Lidar (MABEL), and airborne laser altimeter and imagery campaigns by our research group. These measurements are used to study elevation, elevation change and crevassing throughout the glacier system. Analysis of the imagery from our airborne campaigns provides comprehensive characterizations of the BBGS surface over the course of the surge. Results from the data analysis are compared to numerical modeling experiments.

  17. Relationship between Intrauterine Bacterial Infection and Early Embryonic Developmental Arrest

    Institute of Scientific and Technical Information of China (English)

    Shao-Fei Yan; Xin-Yan Liu; Yun-Fei Cheng; Zhi-Yi Li; Jie Ou; Wei Wang; Feng-Qin Li

    2016-01-01

    Background:Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy.The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear.This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest.Methods:Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion (control group) and from 45 patients who displayed early embryonic developmental arrest (trial group).Results:Intrauterine bacterial infection was discovered in both groups.The infection rate was 24.44% (11/45) in the early embryonic developmental arrest group and 9.09% (3/33) in the artificial abortion group.Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% (6/45),and none was detected in the artificial abortion group.M.luteus infection was significantly different between the groups (P < 0.05 as shown by Fisher's exact test).In addition,no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest.Conclusions:M.luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.

  18. Teenage cardiac arrest following abuse of synthetic cannabis.

    Science.gov (United States)

    Davis, C; Boddington, D

    2015-10-01

    The cardiac effects of many illegal substances (cocaine, methadone) have previously been well described [1,2]. However the association between synthetic cannabis and cardiac arrest is less well documented. Here we describe an out-of-hospital cardiac arrest in a previously healthy 16-year-old female associated with the use of inhaled synthetic cannabis. An electronic systematic search of online databases PubMed and Embase was performed using keywords, "synthetic cannabis death" and "cardiac arrest". In this case study a previously healthy 16-year-old had a cardiac arrest after synthetic cannabis use. Despite extensive investigations no other cause for her arrest was found. To the best of our knowledge there has been one previous case report of cardiac arrest following synthetic cannabis use in a 56-year-old man [3]. This case report augments the relationship between synthetic cannabis and cardiac arrest in the medical community. More awareness surrounding the risk of synthetic cannabinoids is warranted. Copyright © 2015 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  19. The cool surge following flux emergence in a radiation-MHD experiment

    CERN Document Server

    Nóbrega-Siverio, D; Martínez-Sykora, J

    2016-01-01

    Cool and dense ejections, typically H$_{\\alpha}$ surges, often appear alongside EUV or X-Ray coronal jets as a result of the emergence of magnetized plasma from the solar interior. Idealized numerical experiments explain those ejections as being indirectly associated with the magnetic reconnection taking place between the emerging and preexisting systems. However, those experiments miss basic elements that can importantly affect the surge phenomenon. In this paper we study the cool surges using a realistic treatment of the radiation transfer and material plasma properties. To that end, the Bifrost code is used, which has advanced modules for the equation of state of the plasma, photospheric and chromospheric radiation transfer, heat conduction and optically thin radiative cooling. We carry out a 2.5D experiment of the emergence of magnetized plasma through (meso)granular convection cells and the low atmosphere to the corona. Through detailed Lagrange tracing, we study the formation and evolution of the cool e...

  20. Google Earth-based dynamic visualization system for storm surge flood routing

    Institute of Scientific and Technical Information of China (English)

    Liu Donghai; Wang Qian; Zuo Wentao

    2013-01-01

    To describe the dynamic process of flood routing intuitively and realistically when storm surge disaster occurs,a method for ArcGIS data and Google Earth (GE) data integration is proposed,which realizes the impor-ting and integrating of basic geographic information into GE. Based on SketchUp and AutoCAD software,three-dimension (3D) visualization of seawall and other tidal defense structures is achieved. By employing Microsoft Foundation Class Library (MFC),the related system modules and storm surge flood routing dynamic visualization system are developed. Therefore,dynamic visualization of flood routing process and interactive query of sub-merged area and inundated depth are implemented. A practical application case study of Tianjin Binhai New Area provides decision-making support for coastal seawall planning and storm surge disaster prevention and reduction.

  1. 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.

  2. Approximate Nonlinear Modeling of Aircraft Engine Surge Margin Based on Equilibrium Manifold Expansion

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaofeng; ZHAO Lei

    2012-01-01

    Stable operation of aircraft engine compressions is constrained by rotating surge.In this paper,an approximate nonlinear surge margin model of aircraft engine compression system by using equilibrium manifold is presented.Firstly,this paper gives an overview of the current state of modeling aerodynamic flow instabilities in engine compressors.Secondly,the expansion form of equilibrium manifold is introduced,and the choosing scheduling variable method is discussed.Then,this paper also gives the identification procedure of modeling the approximate nonlinear model.Finally,the modeling and simulations with high pressure (HP) compressor surge margin of the aircraft engine show that this real-time model has the same accuracy with the thermodynamic model,but has simpler structure and shorter computation time.

  3. Sedimentological features of the surge emitted during the August, 2006 pyroclastic eruption at Tungurahua volcano (Ecuador)

    Science.gov (United States)

    Douillet, G.; Goldstein, F.; Lavallee, Y.; Hanson, J. B.; Kueppers, U.; Robin, C.; Ramon, P.

    2009-12-01

    Tungurahua volcano, Ecuador, is a stratovolcano, which began a new eruptive phase in 1999. Notable pyroclastic Density Currents (PDC) were generated in July (VEI 2) and August (VEI 3) 2006 and covered its N and W flanks. PDCs and associated lahars represent a major hazard for 20,000 inhabitants and an hydrological dam. The volcano has been monitored by the Instituto Geofisico of the Escuela Politécnica Nacional of Quito, since 1988. Field work carried out in 2009 provide information on the behavior of the fine-grained fraction of the PDC (i.e., surge) during transport and deposition. We mapped out the sedimentological characteristics of the deposits and distinguished three depositional environments: 1- The core of the deposit, up to several m in thickness, is confined to valleys and consists of poorly-sorted lapilli scoria and blocks (cm to m scale) and a small fraction of ash matrix. Ongoing analysis of the ash matrix will help to understand the link between the main PDC and the associated surge. 2- On ridges and outer margins of valleys, the deposits total a thickness of 10s to 100s cm and consist of fine- to coarse-grain ashes organized in cm-scale beds. Horizontal to cross bed laminations with 10-cm long wavelength prevail. They are typical of deposition under sustained high-energy current, which we associate with the flow of a surge. 3- In the distal part of surge deposits, we observe fine grained surge deposits with a thickness up to ca. 5 m. The characteristic structures are curved crested dunes, 10s of cm high and up to 10s of m long, with dip angles ranging from 15 to 35° and a strongly asymmetric shape. The steepest side tends to be the upslope face. Dunes show mainly a climbing structure, with beds cm in thickness, but some are more complicated, containing cut and fill structures, interpreted as late-stage pulses of energetic turbulence. No displacement dunes were observed in this area. Using the flow direction given by 100s of dunes, we provide

  4. 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.

  5. Protection of New York City Urban Fabric With Low-Cost Textile Storm Surge Barriers

    CERN Document Server

    Bolonkin, Alexander

    2007-01-01

    Textile storm surge barriers, sited at multiple locations, are literally extensions of the city world famous urban fabric - another manifestation of the dominance of the City over local Nature. Textile Storm Surge Barriers (TSSB) are intended to preserve the City from North Atlantic Ocean hurricanes that cause sea waves impacting the densely populated and high-value real estate, instigating catastrophic, and possibly long-term, infrastructure and monetary losses. Complicating TSSB installation macroproject planning is the presence of the Hudson and other rivers, several small tidal straits, future climate change and other factors. We conclude that TSSB installations made of homogeneous construction materials are worthwhile investigating because they may be less expensive to build, and more easily replaced following any failure, than concrete and steel storm surge barriers, which are also made of homogeneous materials. We suppose the best macroproject outcome will develop in the perfect Macro-engineering plann...

  6. 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.

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

    Science.gov (United States)

    Peng, Shiqiu; Li, Yineng

    2015-10-26

    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.

  8. Experiment and surge analysis of centrifugal two-stage turbocharging system

    Institute of Scientific and Technical Information of China (English)

    Yituan HE; Chaochen MA

    2008-01-01

    To study a centrifugal two-stage turbocharging system's surge and influencing factors, a special test bench was set up and the system surge test was performed. The test results indicate that the measured parameters such as air mass flow and rotation speed of a high pressure (HP) stage compressor can be converted into corrected para-meters under a standard condition according to the Mach number similarity criterion, because the air flow in a HP stage compressor has entered the Reynolds number (Re) auto-modeling range. Accordingly, the reasons leading to a two-stage turbocharging system's surge can be analyzed according to the corrected mass flow characteristic maps and actual operating conditions of HP and low pressure (LP) stage compressors.

  9. Winter speed-up of quiescent surge-type glaciers in Yukon, Canada

    Science.gov (United States)

    Abe, T.; Furuya, M.

    2015-06-01

    Glacier surges often initiate in winter, but the mechanism remains unclear in contrast to the well-known summer speed-up at normal glaciers. To better understand the mechanism, we used radar images to examine spatial-temporal changes in the ice velocity of surge-type glaciers near the border of Alaska and the Yukon, focusing on their quiescent phase. We found significant accelerations in the upstream region from autumn to winter, regardless of surging episodes. Moreover, the winter speed-up propagated from upstream to downstream. Given the absence of surface meltwater input in winter, we suggest the presence of water storage near the base that does not directly connect to the surface, yet can promote basal sliding through increased water pressure. Our findings have implications for the modelling of glacial hydrology in winter, which may help us better understand glacier dynamics.

  10. Winter speed-up of quiescent surge-type glaciers in Yukon, Canada

    Directory of Open Access Journals (Sweden)

    T. Abe

    2014-05-01

    Full Text Available Glacier surge is known to often initiate in winter, but the mechanisms remain unclear in light of the summer speed-up at normal glaciers. We examined spatial-temporal changes in the ice velocity of surge-type glaciers near the border of Alaska and Yukon, and found significant upstream accelerations from fall to winter, regardless of surging episodes. Moreover, whereas the summer speed-up was observed downstream, the winter speed-up propagated from upstream to downglacier. Given the absence of upstream surface meltwater input in winter, we speculate the presence of water storages near the base that do not directly connect to the surface but can promote basal sliding through increased water pressure as winter approaches. Our findings have implications for modeling of glacial hydrology in winter time, and its link to glacier dynamics and subglacial erosion.

  11. Evolution of the dragonfly head-arresting system

    OpenAIRE

    Gorb, S. N.

    1999-01-01

    The arrester or fixation system of the head in adult Odonata is unique among arthropods. This system involves the organs of two body segments: the head and the neck. It consists of a skeleton–muscle apparatus that sets the arrester parts in motion. The parts comprise formations covered with complicated microstructures: fields of microtrichia on the rear surface of the head and post-cervical sclerites of the neck. The arrester immobilizes the head during feeding or when the dragonfly is in tan...

  12. Friction distribution at the base of a surging glacier inferred from an inverse method

    Science.gov (United States)

    Gagliardini, O.; Jay-Allemand, M.; Gillet-Chaulet, F.

    2010-12-01

    The main objectives of this study is to investigate the basal conditions of a surging glacier. For that, we apply the inverse method proposed by Arthern and Gudmundsson (Journal of Glaciology, 2010). This method is based on an iterative descent algorithm numerically implemented in the finite element code Elmer/Ice. Neumann and Dirichlet problems are solved successively in order to minimize the cost function constructed as the norm of the difference between the basal velocities solutions of both problems. The method is applied to the Variegated glacier, a surge type glacier located in Alaska. We use measurements on this glacier carried out by Raymond and Harrison (Journal of Glaciology, 1988) during the quiescent stage of 1966-81 and the surge of 1982-83. Data contain surface velocities as well as the bed and surface topography along the central flow-line. In a first step, for each set of data obtained at different dates, we run the model diagnostically to solve for the basal drag coefficient in order to match the modelled horizontal surface velocities and the observed velocities. In a second step, inferred basal drag coefficient are analysed and then integrated in a transient simulation which cover the whole period of the data set, i.e. both quiescent and surge stages. Results show the contribution of basal sliding in the surge phenomenon and the modification of the basal condition from the quiescent to the surge stages. These modifications can be interpreted in term of changes in sub-glacial water pressure and runoff.

  13. 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.

  14. 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

  15. A model study of Abrahamsenbreen, a surging glacier in northern Spitsbergen

    Directory of Open Access Journals (Sweden)

    J. Oerlemans

    2014-11-01

    Full Text Available The climate sensitivity of Abrahamsenbreen, a 20 km long surge-type glacier in northern Spitsbergen, is studied with a simple glacier model. A scheme to describe the surges is included, which makes it possible to account for the effect of surges on the total mass budget of the glacier. A climate reconstruction back to AD 1300, based on ice-core data from Lomonosovfonna and climate records from Longyearbyen, is used to drive the model. The model is calibrated by requesting that it produces the correct Little Ice Age maximum glacier length and simulates the observed magnitude of the 1978-surge. Abrahamsenbreen is strongly out of balance with the current climate. If climatic conditions will remain as they were for the period 1989–2010, the glacier will ultimately shrink to a length of about 4 km (but this will take hundreds of years. For a climate change scenario involving a 2 m yr−1 rise of the equilibrium line from now onwards, we predict that in the year 2100 Abrahamsenbreen will be about 12 km long. The main effect of a surge is to lower the mean surface elevation and to increase the ablation area, thereby causing a negative perturbation of the mass budget. We found that the occurrence of surges leads to a somewhat stronger retreat of the glacier in a warming climate. Because of the very small bed slope, Abrahamsenbreen is sensitive to small perturbations in the equilibrium-line altitude E. For a decrease of E of only 160 m, the glacier would steadily grow into the Woodfjorddalen until after 2000 years it would reach the Woodfjord and calving could slow down the advance.

  16. 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.

  17. 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.

  18. 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.

  19. Neurological and circulatory outcomes of cardiopulmonary resuscitation in progress: influence of pre-arrest and arrest factors.

    Science.gov (United States)

    Jørgensen, E O

    1998-01-01

    Possible correlations between the circulatory and neurological responses to cardiopulmonary resuscitation (CPR) and the influence of pre-arrest factors (demographic data, medical history and aetiology of circulatory arrest) and arrest factors (location of arrest, ECG configurations, and duration of resuscitation) on the course of circulatory and neurological recovery were investigated in 111 victims of circulatory arrest. At the start of resuscitation 57 patients (Group I) had some brain function and 54 (Group II) had no brain function. Sixty nine patients (62%) had circulation restored but 54 (78%) were left with heart failure. Forty one patients (39%) survived the first day, 26 (63%) with heart failure; only 34 (31%) were alive after 48 h, 17 (50%) with heart failure. Half of the patients surviving 24 or 48 h had awakened. Consciousness returned in 32 patients (29%) during the first 48 h, more frequently in Group I than in Group II. Patients in Group I had a higher incidence of in-hospital arrest and had their circulation restored more often than those in Group II. Survival and post-resuscitation heart failure was alike in the groups. The pre-arrest factors explored did not modify the circulatory or neurological outcome whereas initial ventricular fibrillation was significantly related to recovery of consciousness. The revivability of spontaneous circulation and of neurological functions was found thus mainly to be determined by global ischaemia sustained prior to and during CPR.

  20. 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

    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...... 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...

  1. Surge motion of an ice floe in waves: comparison of theoretical and experimental models

    CERN Document Server

    Meylan, Michael; Bennetts, Luke; French, Benjamin; Thomas, Giles

    2014-01-01

    A theoretical model and an experimental model of surge motions of an ice floe due to regular waves are presented. The theoretical model is a modified version of Morrison's equation, valid for small floating bodies. The experimental model is implemented in a wave basin at scale 1:100, using a thin plastic disk to model the floe. The processed experimental data displays a regime change in surge amplitude when the incident wavelength is approximately twice the floe diameter. It is shown that the theoretical model is accurate in the large wavelength regime, but highly inaccurate for the small wavelength regime.

  2. Modelling of variable speed centrifugal compressors for anti-surge control

    OpenAIRE

    Aaslid, Per

    2009-01-01

    A mathematical model for simulation of gas compressor systems is developed. The model is designed for anti-surge control validation, and models a continuous flow gas compressor. The model also includes a cooler for gas cooling, a scrubber for liquid draining, and a recycle line with a control valve for anti-surge control. The system outlet has a check valve to prevent reversed flows. The model is one-dimensional and models pressure, temperature and mass flow for all system components, and als...

  3. Implementation and application of a nested numerical storm surge forecast model in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    于福江; 张占海

    2002-01-01

    A nested numerical storm surge forecast model for the East China Sea is developed. A one-way relaxing nest method is used to exchange the information between coarse grid and fine grid. In the inner boundary of the fine grid model a transition area is set up to relax the forecast variables. This ensures that the forecast variables of the coarse model may transit to those of fine grid gradually, which enhances the model stability. By using this model, a number of hindcasts and forecast are performed for six severe storm surges caused by tropical cyclones in the East China Sea. The results show good agreement with the observations.

  4. 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.

  5. A new concept for glacial geological investigations of surges, based on High-Arctic examples (Svalbard)

    Science.gov (United States)

    Lønne, Ida

    2016-01-01

    Svalbard is a key area for the investigation of glacial surges, and almost two centuries worth of field observations exists from this region. Studies have shown that the course of a surge and the associated formation of landforms are strongly influenced by basinal factors, and that the broad range of variables involved can hamper interpretations and comparisons. Based on a review of surges in Svalbard, a new concept for glacial geological investigations has been developed that combines ice-flows, ice-front movements, and morphostratigraphy. The concept is comprised of the following four elements: 1) classification based on the configuration and characteristics of the receiving basin, 2) division of the surge cycle into six stages, 3) guidelines for morphological mapping, and 4) use of an allostratigraphic approach for interpreting ice-front movements. In this context, delineation of the active phase is critical, which include the history of terminus movements, and four main categories of receiving basins are recognized. These are (A) terrestrial basins with deformable substrates, (B) terrestrial basins with poorly deformable substrates, (C) shallow water basins, and (D) deep water basins. The ice-front movement history is reconstructed by coupling information from the proglacial moraines (syn-surge), the supraglacial moraines (post-surge), and the associated traces of meltwater to the surge stages (I-VI). This approach has revealed a critical relationship between the termination of the active phase and three morphological elements, namely, the maximum ice-front position, the maximum moraine extent and the youngest proglacial moraine, which are unique for each of the basins A-D. The concept is thus a novel and more precise approach for mapping the active phase and the active phase duration, as shown by the ∼12-year long surge of Fridtjovbreen, where stage I was 30 months (inception), stage II was 54 months (ice-front advance), stage III was 12 months (stillstand

  6. Effects of seismic surge waves and implications for moraine-dammed lake outburst

    Science.gov (United States)

    Du, Cui; Yao, Lingkan; Huang, Yidan; Yan, Jiahong; Shakya, Subhashsagar

    2016-09-01

    Moraine dams usually collapse due to overtopping by the surge wave in the dammed lake, and the surge wave is most likely caused by an earthquake. The seismic water wave (SWW) is a major factor causing the dam to break in the earthquake zone. This paper focused on the SWW by model experiments with a shaking water tank under conditions of various water depths, seismic waves, and peak ground accelerations. Two empirical equations were obtained for estimating maximal wave height for the low and high frequency, respectively. Finally, we present the application of the empirical equations on Midui Glacier Lake in Tibet plateau.

  7. Analysis of vehicle surge. Relationship with the coefficient of variation in combustion of engine; Sharyo surge no kaiseki. Engine nensho hendoritsu tono kankei

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, H. [Subaru Research Center Co. Ltd., Tokyo (Japan)

    1998-05-01

    Leaning of great magnitude and increase in EGR rate are being moved forward to reduce fuel consumption and improve exhaust gas emission, where variation in combustion is one of the important evaluation items. No studies can be found to date, which express the relationship between variation in combustion and vehicle surge as a specific numerical function including vehicle characteristics. Forward and rearward vehicle acceleration may be expressed by root mean square (RMS) of square mean of instantaneous acceleration. The Parseval`s theorem was used to convert the forward and rearward vehicle acceleration and time function of engine torque into a frequency function, and to perform an analysis in the frequency region. It was made clear that, when engine rotation speed is 1200 rpm or higher, or if there is no torque deviation between cylinders, vehicle surge can be expressed as the vehicle power characteristic value, the drivetrain characteristic value, the indicated mean effective pressure, the torque shape coefficient, the surge rate, and the product of the combustion variation coefficient. The drivetrain characteristic value could be said a dynamic total reduction gear ratio, and is a function of the drivetrain factors, which are largely affected especially by the mechanical loss factor of tires and suspension systems. 6 refs., 7 figs., 2 tabs.

  8. Improvements of Storm Surge Modelling in the Gulf of Venice with Satellite Data: The ESA Due Esurge-Venice Project

    Science.gov (United States)

    De Biasio, F.; Bajo, M.; Vignudelli, S.; Papa, A.; della Valle, A.; Umgiesser, G.; Donlon, C.; Zecchetto, S.

    2016-08-01

    Among the most detrimental natural phenomena, storm surges heavily endanger the environment, the economy and the everyday life of sea-side countries and coastal zones. Considering that 120.000.000 people live in the Mediterranean area, with additional 200.000.000 presences in Summer for tourism purposes, the correct prediction of storm surges is crucial to avoid fatalities and economic losses. Earth Observation (EO) can play an important role in operational storm surge forecasting, yet it is not widely diffused in the storm surge community. In 2011 the European Space Agency (ESA), through its Data User Element (DUE) programme, financed two projects aimed at encouraging the uptake of EO data in this sector: eSurge and eSurge-Venice (eSV). The former was intended to address the issues of a wider users' community, while the latter was focused on a restricted geographical area: the northern Adriatic Sea and the Gulf of Venice. Among the objectives of the two projects there were a number of storm surge hindcast experiments using satellite data, to demonstrate the improvements on the surge forecast brought by EO. We report here the results of the hindcast experiments of the eSV project. They were aimed to test the sensitivity of a storm surge model to a forcing wind field modified with scatterometer data in order to reduce the bias between simulated and observed winds. Hindcast experiments were also performed to test the response of the storm surge model to the assimilation, with a dual 4D-Var system, of satellite altimetry observations as model errors of the initial state of the sea surface level. Remarkable improvements on the storm surge forecast have been obtained for what concerns the modified model wind forcing. Encouraging results have been obtained also in the assimilation experiments.

  9. The outcome of anaesthesia related cardiac arrest in a

    Directory of Open Access Journals (Sweden)

    O.O. Adekola

    2016-07-01

    Conclusion: Anaesthesia related cardiac arrest and mortality were linked to cardiovascular depression from halothane overdose in our institution. The burden can be reduced by improving on establishing standard monitoring in the perioperative period, and a team approach to patients care.

  10. Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Takahashi

    Full Text Available A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells.

  11. Adapting NEMO for use as the UK operational storm surge forecasting model

    Science.gov (United States)

    Furner, Rachel; Williams, Jane; Horsburgh, Kevin; Saulter, Andrew

    2016-04-01

    The United Kingdom is an area vulnerable to damage due to storm surges, particularly the East Coast which suffered losses estimated at over £1 billion during the North Sea surge event of the 5th and 6th December 2013. Accurate forecasting of storm surge events for this region is crucial to enable government agencies to assess the risk of overtopping of coastal defences so they can respond appropriately, minimising risk to life and infrastructure. There has been an operational storm surge forecast service for this region since 1978, using a numerical model developed by the National Oceanography Centre (NOC) and run at the UK Met Office. This is also implemented as part of an ensemble prediction system, using perturbed atmospheric forcing to produce an ensemble surge forecast. In order to ensure efficient use of future supercomputer developments and to create synergy with existing operational coastal ocean models the Met Office and NOC have begun a joint project transitioning the storm surge forecast system from the current CS3X code base to a configuration based on the Nucleus for European Modelling of the Ocean (NEMO). This work involves both adapting NEMO to add functionality, such as allowing the drying out of ocean cells and changes allowing NEMO to run efficiently as a two-dimensional, barotropic model. As the ensemble surge forecast system is run with 12 members 4 times a day computational efficiency is of high importance. Upon completion this project will enable interesting scientific comparisons to be made between a NEMO based surge model and the full three-dimensional baroclinic NEMO based models currently run within the Met Office, facilitating assessment of the impact of baroclinic processes, and vertical resolution on sea surface height forecasts. Moving to a NEMO code base will also allow many future developments to be more easily used within the storm surge model due to the wide range of options which currently exist within NEMO or are planned for

  12. Usage of Lightning Arrester Line to Feed Light Electrical Loads

    Directory of Open Access Journals (Sweden)

    Hani B. Odeh

    2009-01-01

    Full Text Available In remote areas, light loads (tens of kilowatts are scattered and situated in the field of high voltage lines (66KV and above. These loads are very far from the main feeders/sub-stations (33KV-0.380KV. Feeding such loads in the traditional ways like provision of Diesel-Powered Stations, installation of new distribution lines from the Feeding Centers, or building new Sub-Stations are not practical ways from the economical point of view, because it requires huge additional expenses and will increase electrical power losses. These expenses are not worthy for such loads and therefore, it is necessary to search for other methods to supply them. One of these methods is to use the lightning arrester line as capacitive divider to supply the light loads. In this research, the induced voltage of the lightning arrester line was calculated when it is isolated from the earth. We found the capacitance between lightning arrester line versus the phases and lightning arrester. It was also found the selective power out of the lightning arrester line and the required length which is to be isolated from the earth keeping the main function of the lightning arrester line. When economically comparing between supplying the light electrical loads by traditional ways and the method of lightning arrester, it was found the advantage of using lightning arresters to supply such loads. Also, by using the traditional methods, it was noted that there is a power loss in the power transmission lines by a percentage of 1.8%.

  13. Al-Qaeda arrest casts shadow over the LHC

    CERN Multimedia

    Dacey, James

    2010-01-01

    "Cern remains on course for the imminent switch-on of the Large Hadron Collider (LHC) despite the media frenzy following the recent arrest of a physicist who had been working at the facility. The researcher in question is a 32-year-old man of Algerian descent who is expected to face trail in France - the country in which he was arrested" (0.5 page)

  14. Cardiac arrest due to lymphocytic colitis: a case report

    Directory of Open Access Journals (Sweden)

    Groth Kristian A

    2012-03-01

    Full Text Available Abstract Introduction We present a case of cardiac arrest due to hypokalemia caused by lymphocytic colitis. Case presentation A 69-year-old Caucasian man presented four months prior to a cardiac arrest with watery diarrhea and was diagnosed with lymphocytic colitis. Our patient experienced a witnessed cardiac arrest at his general practitioner's surgery. Two physicians and the emergency medical services resuscitated our patient for one hour and four minutes before arriving at our university hospital. Our patient was defibrillated 16 times due to the recurrence of ventricular tachyarrhythmias. An arterial blood sample revealed a potassium level of 2.0 mmol/L (reference range: 3.5 to 4.6 mmol/L and pH 6.86 (reference range: pH 7.37 to 7.45. As the potassium level was corrected, the propensity for ventricular tachyarrhythmias ceased. Our patient recovered from his cardiac arrest without any neurological deficit. Further tests and examinations revealed no other reason for the cardiac arrest. Conclusion Diarrhea can cause life-threatening situations due to the excretion of potassium, ultimately causing cardiac arrest due to hypokalemia. Physicians treating patients with severe diarrhea should consider monitoring their electrolyte levels.

  15. Respiratory Arrest in an Obese Pregnant Woman with Hyperemesis Gravidarum

    Directory of Open Access Journals (Sweden)

    Ayumi Iwashita

    2015-01-01

    Full Text Available A pregnant, non-Japanese-speaking Peruvian, and, thus, with communication difficulty, suffered hyperemesis gravidarum and had respiratory arrest, requiring cardiopulmonary resuscitation. The obese pregnant woman (prepregnancy weight: 107 kg had vomited and lost 15 kg in bodyweight over appropriately 2 weeks prior to the arrest but had not complained due to communication difficulty, which, together with her obesity, prevented a Japanese obstetrician from noticing her severe condition. 1,000 mL of low potassium fluid plus thiamine was administered. She became unable to stand, suggesting lower-extremity-proximal-muscle weakness, and then respiratory arrest occurred. Hypopotassemia (2.3 mEq/L, pulseless electrical activity, and muscle weakness suggested the presence of severe potassium deficiency, which may have caused respiratory muscle paralysis, leading to the respiratory arrest. Hypercapnea was severer than expected for compensatory hypoventilation, indicating the presence of concomitant severe hypoventilation, which may also have contributed to respiratory arrest. She recovered with electrolyte and volume replacement. Respiratory arrest can occur with hyperemesis gravidarum, and obesity and communication difficulties can prevent the early detection of severe conditions.

  16. Associates of Cardiopulmonary Arrest in the Perihemodialytic Period

    Directory of Open Access Journals (Sweden)

    Jennifer E. Flythe

    2014-01-01

    Full Text Available Cardiopulmonary arrest during and proximate to hemodialysis is rare but highly fatal. Studies have examined peridialytic sudden cardiac event risk factors, but no study has considered associates of cardiopulmonary arrests (fatal and nonfatal events including cardiac and respiratory causes. This study was designed to elucidate patient and procedural factors associated with peridialytic cardiopulmonary arrest. Data for this case-control study were taken from the hemodialysis population at Fresenius Medical Care, North America. 924 in-center cardiopulmonary events (cases and 75,538 controls were identified. Cases and controls were 1 : 5 matched on age, sex, race, and diabetes. Predictors of cardiopulmonary arrest were considered for logistic model inclusion. Missed treatments due to hospitalization, lower body mass, coronary artery disease, heart failure, lower albumin and hemoglobin, lower dialysate potassium, higher serum calcium, greater erythropoietin stimulating agent dose, and normalized protein catabolic rate (J-shaped were associated with peridialytic cardiopulmonary arrest. Of these, lower albumin, hemoglobin, and body mass index; higher erythropoietin stimulating agent dose; and greater missed sessions had the strongest associations with outcome. Patient health markers and procedural factors are associated with peridialytic cardiopulmonary arrest. In addition to optimizing nutritional status, it may be prudent to limit exposure to low dialysate potassium (<2 K bath and to use the lowest effective erythropoietin stimulating agent dose.

  17. Cardiopulmonary resuscitation for cardiac arrest: the importance of uninterrupted chest compressions in cardiac arrest resuscitation.

    Science.gov (United States)

    Cunningham, Lee M; Mattu, Amal; O'Connor, Robert E; Brady, William J

    2012-10-01

    Over the last decade, the importance of delivering high-quality cardiopulmonary resuscitation (CPR) for cardiac arrest patients has become increasingly emphasized. Many experts are in agreement concerning the appropriate compression rate, depth, and amount of chest recoil necessary for high-quality CPR. In addition to these factors, there is a growing body of evidence supporting continuous or uninterrupted chest compressions as an equally important aspect of high-quality CPR. An innovative resuscitation protocol, called cardiocerebral resuscitation, emphasizes uninterrupted chest compressions and has been associated with superior rates of survival when compared with traditional CPR with standard advanced life support. Interruptions in chest compressions during CPR can negatively impact outcome in cardiac arrest; these interruptions occur for a range of reasons, including pulse determinations, cardiac rhythm analysis, electrical defibrillation, airway management, and vascular access. In addition to comparing cardiocerebral resuscitation to CPR, this review article also discusses possibilities to reduce interruptions in chest compressions without sacrificing the benefit of these interventions. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Exploration of the arrest peptide sequence space reveals arrest-enhanced variants.

    Science.gov (United States)

    Cymer, Florian; Hedman, Rickard; Ismail, Nurzian; von Heijne, Gunnar

    2015-04-17

    Translational arrest peptides (APs) are short stretches of polypeptides that induce translational stalling when synthesized on a ribosome. Mechanical pulling forces acting on the nascent chain can weaken or even abolish stalling. APs can therefore be used as in vivo force sensors, making it possible to measure the forces that act on a nascent chain during translation with single-residue resolution. It is also possible to score the relative strengths of APs by subjecting them to a given pulling force and ranking them according to stalling efficiency. Using the latter approach, we now report an extensive mutagenesis scan of a strong mutant variant of the Mannheimia succiniciproducens SecM AP and identify mutations that further increase the stalling efficiency. Combining three such mutations, we designed an AP that withstands the strongest pulling force we are able to generate at present. We further show that diproline stretches in a nascent protein act as very strong APs when translation is carried out in the absence of elongation factor P. Our findings highlight critical residues in APs, show that certain amino acid sequences induce very strong translational arrest and provide a toolbox of APs of varying strengths that can be used for in vivo force measurements.

  19. 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.

  20. 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.

  1. 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.

  2. 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 w

  3. 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 w

  4. 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 recru...

  5. Assessing the hydrodynamic boundary conditions for risk analyses in coastal areas: a stochastic storm surge model

    Directory of Open Access Journals (Sweden)

    T. Wahl

    2011-11-01

    Full Text Available This paper describes a methodology to stochastically simulate a large number of storm surge scenarios (here: 10 million. The applied model is very cheap in computation time and will contribute to improve the overall results from integrated risk analyses in coastal areas. Initially, the observed storm surge events from the tide gauges of Cuxhaven (located in the Elbe estuary and Hörnum (located in the southeast of Sylt Island are parameterised by taking into account 25 parameters (19 sea level parameters and 6 time parameters. Throughout the paper, the total water levels are considered. The astronomical tides are semidiurnal in the investigation area with a tidal range >2 m. The second step of the stochastic simulation consists in fitting parametric distribution functions to the data sets resulting from the parameterisation. The distribution functions are then used to run Monte-Carlo-Simulations. Based on the simulation results, a large number of storm surge scenarios are reconstructed. Parameter interdependencies are considered and different filter functions are applied to avoid inconsistencies. Storm surge scenarios, which are of interest for risk analyses, can easily be extracted from the results.

  6. The Cool Surge Following Flux Emergence in a Radiation-MHD Experiment

    Science.gov (United States)

    Nóbrega-Siverio, D.; Moreno-Insertis, F.; Martínez-Sykora, J.

    2016-05-01

    Cool and dense ejections, typically Hα surges, often appear alongside EUV or X-ray coronal jets as a result of the emergence of magnetized plasma from the solar interior. Idealized numerical experiments explain those ejections as being indirectly associated with the magnetic reconnection taking place between the emerging and preexisting systems. However, those experiments miss basic elements that can importantly affect the surge phenomenon. In this paper we study the cool surges using a realistic treatment of the radiation transfer and material plasma properties. To that end, the Bifrost code is used, which has advanced modules for the equation of state of the plasma, photospheric and chromospheric radiation transfer, heat conduction, and optically thin radiative cooling. We carry out a 2.5D experiment of the emergence of magnetized plasma through (meso) granular convection cells and the low atmosphere to the corona. Through detailed Lagrange tracing we study the formation and evolution of the cool ejection and, in particular, the role of the entropy sources; this allows us to discern families of evolutionary patterns for the plasma elements. In the launch phase, many elements suffer accelerations well in excess of gravity; when nearing the apex of their individual trajectories, instead, the plasma elements follow quasi-parabolic trajectories with accelerations close to {g}⊙ . We show how the formation of the cool ejection is mediated by a wedge-like structure composed of two shocks, one of which leads to the detachment of the surge from the original emerged plasma dome.

  7. An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

    Science.gov (United States)

    Wernet, Mark P.; Bright, Michelle M.; Skoch, Gary J.

    2002-01-01

    Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to successfully control these events. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to simultaneously capture transient velocity and pressure measurements in the non-stationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique which is ideally suited for studying transient flow phenomena in high speed turbomachinery and has been used previously to successfully map the stable operating point flow field in the diffuser of a high speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

  8. 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.

  9. 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…

  10. 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.

  11. A Theoretical Basis for Surges of Electroencephalogram Activity and Vivid Mental Sensation during Near Death Experience

    Directory of Open Access Journals (Sweden)

    Kanad Ray

    2010-10-01

    Full Text Available According to Chawla et. al.[1]near-death experiences could be caused by a surge of electrical energy released. We account for this spike using an electromagnetic-physiological theory based on transmission line model plus cortical network activity and using known properties of forward and backward propagating waves proposed earlier[2-5

  12. Effects of winds, tides and storm surges on ocean surface waves in the Sea of Japan

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; TIAN Jiwei; LI Peiliang; HOU Yijun

    2007-01-01

    Ocean surface waves are strongly forced by high wind conditions associated with winter storms in the Sea of Japan. They are also modulated by tides and storm surges. The effects of the variability in surface wind forcing, tides and storm surges on the waves are investigated using a wave model, a high-resolution atmospheric mesoscale model and a hydrodynamic ocean circulation model. Five month-long wave model simulations are inducted to examine the sensitivity of ocean waves to various wind forcing fields, tides and storm surges during January 1997. Compared with observed mean wave parameters, results indicate that the high frequency variability in the surface wind filed has very great effect on wave simulation. Tides and storm surges have a significant impact on the waves in nearshores of the Tsushima-kaihyō, but not for other regions in the Sea of Japan. High spatial and temporal resolution and good quality surface wind products will be crucial for the prediction of surface waves in the JES and other marginal seas, especially near the coastal regions.

  13. 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

  14. Numerical Modeling of a Marine Propeller Undergoing Surge and Heave Motion

    Directory of Open Access Journals (Sweden)

    Spyros A. Kinnas

    2012-01-01

    Full Text Available A boundary element method (BEM and a vortex-lattice method (VLM are extended in order to predict the unsteady performance of propellers subject to rigid body motions. The methods are applied in the case of prescribed surge and heave motions, and the results are compared with those from other methods.

  15. 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 t

  16. Performance analysis of traffic surges in multi-class communication networks

    NARCIS (Netherlands)

    Jonckheere, M.T.S.; Núñez-Queija, R.; Prabhu, B.J.

    2010-01-01

    In multi-class communication networks, traffic surges due to one class of users can significantly degrade the performance for other classes. During these transient periods, it is thus of crucial importance to implement priority mechanisms allowing the conservation of the quality of service experienc

  17. 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)

  18. Probabilistic design of the steel structure of the new waterway storm surge barrier

    NARCIS (Netherlands)

    Manen, S.E. van; Vrouwenvelder, A.C.W.M.; Foeken, R.J. van

    1996-01-01

    As part of the sea defence system along the Dutch coast, a storm surge barrier is under construction in the New Waterway, near Rotterdam. The Dutch Ministry of Public Works requires for this structure that the probability of failure is at most 10' per year (104 in life time of 100 years). This is al

  19. 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 t

  20. 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 induc...

  1. DIBROMOACETIC ACID ATTENUATES A DIMETHYLDITHIOCARBAMATE-INDUCED SUPPRESSION OF THE RAT LH SURGE

    Science.gov (United States)

    DIBROMOACETIC ACID ATTENUATES A DITHIOCARBAMATE-INDUCED SUPPRESSION OF THE LH SURGE IN THE RAT. Jerome M. Goldman, Ashley S. Murr, Angela R. Buckelew, W. Keith McElroy and Janet M. Ferrell. Repro. Toxicol. Div., NHEERL, ORD, US EPA, RTP, NCAt elevated concentrations, the ...

  2. 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

  3. 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.

  4. 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.

  5. [Perioperative cardiac arrest: an evolutionary analysis of the intra-operative cardiac arrest incidence in tertiary centers in Brazil].

    Science.gov (United States)

    Vane, Matheus Fachini; do Prado Nuzzi, Rafael Ximenes; Aranha, Gustavo Fabio; da Luz, Vinicius Fernando; Sá Malbouisson, Luiz Marcelo; Gonzalez, Maria Margarita Castro; Auler, José Otávio Costa; Carmona, Maria José Carvalho

    2016-01-01

    Great changes in medicine have taken place over the last 25 years worldwide. These changes in technologies, patient risks, patient profile, and laws regulating the medicine have impacted the incidence of cardiac arrest. It has been postulated that the incidence of intraoperative cardiac arrest has decreased over the years, especially in developed countries. The authors hypothesized that, as in the rest of the world, the incidence of intraoperative cardiac arrest is decreasing in Brazil, a developing country. The aim of this study was to search the literature to evaluate the publications that relate the incidence of intraoperative cardiac arrest in Brazil and analyze the trend in the incidence of intraoperative cardiac arrest. There were 4 articles that met our inclusion criteria, resulting in 204,072 patients undergoing regional or general anesthesia in two tertiary and academic hospitals, totalizing 627 cases of intraoperative cardiac arrest. The mean intraoperative cardiac arrest incidence for the 25 years period was 30.72:10,000 anesthesias. There was a decrease from 39:10,000 anesthesias to 13:10,000 anesthesias in the analyzed period, with the related lethality from 48.3% to 30.8%. Also, the main causes of anesthesia-related cause of mortality changed from machine malfunction and drug overdose to hypovolemia and respiratory causes. There was a clear reduction in the incidence of intraoperative cardiac arrest in the last 25 years in Brazil. This reduction is seen worldwide and might be a result of multiple factors, including new laws regulating the medicine in Brazil, incorporation of technologies, better human development level of the country, and better patient care. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

  6. Perioperative cardiac arrest: an evolutionary analysis of the intra-operative cardiac arrest incidence in tertiary centers in Brazil.

    Science.gov (United States)

    Vane, Matheus Fachini; do Prado Nuzzi, Rafael Ximenes; Aranha, Gustavo Fabio; da Luz, Vinicius Fernando; Sá Malbouisson, Luiz Marcelo; Gonzalez, Maria Margarita Castro; Auler, José Otávio Costa; Carmona, Maria José Carvalho

    2016-01-01

    Great changes in medicine have taken place over the last 25 years worldwide. These changes in technologies, patient risks, patient profile, and laws regulating the medicine have impacted the incidence of cardiac arrest. It has been postulated that the incidence of intraoperative cardiac arrest has decreased over the years, especially in developed countries. The authors hypothesized that, as in the rest of the world, the incidence of intraoperative cardiac arrest is decreasing in Brazil, a developing country. The aim of this study was to search the literature to evaluate the publications that relate the incidence of intraoperative cardiac arrest in Brazil and analyze the trend in the incidence of intraoperative cardiac arrest. There were 4 articles that met our inclusion criteria, resulting in 204,072 patients undergoing regional or general anesthesia in two tertiary and academic hospitals, totalizing 627 cases of intraoperative cardiac arrest. The mean intraoperative cardiac arrest incidence for the 25 years period was 30.72:10,000 anesthesias. There was a decrease from 39:10,000 anesthesias to 13:10,000 anesthesias in the analyzed period, with the related lethality from 48.3% to 30.8%. Also, the main causes of anesthesia-related cause of mortality changed from machine malfunction and drug overdose to hypovolemia and respiratory causes. There was a clear reduction in the incidence of intraoperative cardiac arrest in the last 25 years in Brazil. This reduction is seen worldwide and might be a result of multiple factors, including new laws regulating the medicine in Brazil, incorporation of technologies, better human development level of the country, and better patient care. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  7. Comparing and Contrasting the Benefits of Land Mass vs. Land Cover on Storm Surge Attenuation

    Science.gov (United States)

    Siverd, C. G.; Hagen, S. C.; Bilskie, M. V.; Twilley, R.; Braud, D.; Peele, H.

    2015-12-01

    From 1930 through 2012 Louisiana lost approximately 1,880 sq mi (4,870 sq km) of coastal wetlands due to land subsidence, erosion, and sea level rise among other factors. Louisiana could potentially lose an additional 1,750 sq mi (4,530 sq km) of coastal wetlands by 2062 if no action is taken to prevent this land loss (CPRA, 2012). If risk is defined as probability multiplied by consequence (Vrijling, 2006), such land loss will significantly increase the risk of flooding in coastal communities and communities located farther inland. Vital coastal infrastructure will also be at a heightened risk of flood damage. This will be attributable to the increase in frequency of hurricane storm surge events featuring greater depths and farther inland extent. This risk can be described by contrasting the surface area of land and water along the Louisiana coast. Using aerial or satellite imagery, isopleths can be plotted along the coast that describe the land to water (L:W) ratio over time (e.g., Gagliano et al., 1970, 1971 plotted the calculated 50% L:W ratio isopleths for the years 1930, and 1970, with an estimated 2000 isopleth). Risk to coastal infrastructure and coastal communities increases as the L:W ratio is reduced. One possible way to reduce the depth and extent of storm surge is to increase the land area along the coast. A second way is to modify the land cover (i.e. vary the type and density of vegetation). The L:W ratio can be used to quantify storm surge attenuation and assess such contributing factors. For this study, storm surge is simulated along coastal Louisiana for various instances - with increased land area and separately with different land cover types and densities - to determine which of these factors most effectively reduce the depth and extent of storm surge. New metrics involving hydrologic basins for evaluating storm surge attenuation are also described. The results of this study should inform policy makers which factors contribute the most to storm

  8. 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

  9. Development of Storm Surge Hazard Maps and Advisory System for the Philippines

    Science.gov (United States)

    Santiago, Joy; Mahar Francisco Lagymay, Alfredo; Caro, Carl Vincent; Suarez, John Kenneth; Tablazon, Judd; Dasallas, Lea; Garnet Goting, Prince

    2016-04-01

    The Philippines, located in the most active region of cyclogenesis in the world, experiences an average of 20 tropical cyclones annually. Strong winds brought by tropical cyclones, among other factors, cause storm surges that inundate the coastal areas of the country. As an archipelago with the fourth longest coastline in the world, the country is expose to the threats of storm surges. This was manifested by Typhoon Haiyan on 8 November 2013, which devastated the country and left 6,293 deaths and approximately USD 2 billion worth of damages. To prevent such disaster from happening again, the Nationwide Operational Assessment of Hazards (Project NOAH) developed a Storm Surge Advisory (SSA) that aims to warn communities in coastal areas against impending floods due to storm surges. The Japan Meteorological Agency storm surge model was used to simulate 721 tropical cyclones that entered the Philippine Area of Responsibility from 1951-2013. The resulting storm surge time series from the simulations were added to the maximum tide levels from the WXTide software for the 4,996 observation points placed nearshore in the entire country. The storm tide levels were categorized into four groups based on their peak height to create the SSA - SSA 1 (0.01m to 2m), SSA 2 (2.01m to 3m), SSA 3 (3.01m to 4m), and SSA 4 (4m and above). The time series for each advisory level was used in inundation modelling using FLO-2D, a two-dimensional flood modeling software that uses continuity and dynamic wave momentum equation. The model produced probable extent, depth of inundation, and hazard level for each advisory level. The SSA hazard maps are used as reference to warn communities that are likely to be affected by storm surges. Advisory is released 24 hours in advance and is updated every six hours in the Project NOAH website. It is also being utilized in the pre-disaster risk assessment of the national government agencies and local government units in designing appropriate response to

  10. 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

    2016-05-01

    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. 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. 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. 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 also been instrumental in building local capacity

  11. Characterization of mitochondrial injury after cardiac arrest (COMICA).

    Science.gov (United States)

    Donnino, Michael W; Liu, Xiaowen; Andersen, Lars W; Rittenberger, Jon C; Abella, Benjamin S; Gaieski, David F; Ornato, Joseph P; Gazmuri, Raúl J; Grossestreuer, Anne V; Cocchi, Michael N; Abbate, Antonio; Uber, Amy; Clore, John; Peberdy, Mary Anne; Callaway, Clifton W

    2017-04-01

    Mitochondrial injury post-cardiac arrest has been described in pre-clinical settings but the extent to which this injury occurs in humans remains largely unknown. We hypothesized that increased levels of mitochondrial biomarkers would be associated with mortality and neurological morbidity in post-cardiac arrest subjects. We performed a prospective multicenter study of post-cardiac arrest subjects. Inclusion criteria were comatose adults who suffered an out-of-hospital cardiac arrest. Mitochondrial biomarkers were measured at 0, 12, 24, 36 and 48h after return of spontaneous circulation as well as in healthy controls. Out of 111 subjects enrolled, 102 had evaluable samples at 0h. Cardiac arrest subjects had higher baseline cytochrome c levels compared to controls (2.18ng/mL [0.74, 7.74] vs. 0.16ng/mL [0.03, 0.91], p<0.001), and subjects who died had higher 0h cytochrome c levels compared to survivors (3.66ng/mL [1.40, 14.9] vs. 1.27ng/mL [0.16, 2.37], p<0.001). There were significantly higher Ribonuclease P (RNaseP) (3.3 [1.2, 5.7] vs. 1.2 [0.8, 1.2], p<0.001) and Beta-2microglobulin (B2M) (12.0 [1.0, 22.9], vs. 0.6 [0.6, 1.3], p<0.001) levels in cardiac arrest subjects at baseline compared to the control subjects. There were no differences between survivors and non-survivors for mitochondrial DNA, nuclear DNA, or cell free DNA. Cytochrome c was increased in post- cardiac arrest subjects compared to controls, and in post-cardiac arrest non-survivors compared to survivors. Nuclear DNA and cell free DNA was increased in plasma of post-cardiac arrest subjects. There were no differences in mitochondrial DNA, nuclear DNA, or cell free DNA between survivors and non-survivors. Mitochondrial injury markers showed mixed results in the post-cardiac arrest period. Future research needs to investigate these differences. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Winter speed-up of ice flow at quiescent surge-type glaciers in Yukon, Canada

    Science.gov (United States)

    Furuya, M.; Abe, T.

    2013-12-01

    Glacier surge exhibits order-of-magnitude faster velocity and km-scale terminus advance during its short active phase after a long quiescent period. The observations of glacier surge are still limited, and the mechanisms of glacier surge cycle remain elusive. Moreover, with the exception of several well-examined glaciers, the glacier dynamics during their quiescent periods remains even more uncertain due to the paucity of surface velocity measurement data. Here we examined spatial-temporal changes in the ice surface velocity of surge-type glaciers in the St. Elias Mountains near the border of Alaska and Yukon during the period from December 2006 to March 2011. We applied the offset-tracking (feature-tracking) technique to the L-band synthetic aperture radar (SAR) images derived from the Japanese Advanced Land Observation Satellite (ALOS). The Chitina, Anderson, Walsh, and Logan Glaciers, the major subpolar surge-type glaciers of the Chitina River valley system, could be examined with the highest temporal resolution because of the overlap of multiple satellite tracks. We have found significant upstream accelerations from fall to winter at a number of glaciers during their quiescence. Moreover, whereas the upstream propagating summer speed-up was observed, the winter speed-up propagated from upstream to downglacier. Although the winter speed-up seems to be at odds with the well-known summer speed-up, these observations are consistent with the fragmentary but well-known fact of glacier surge that often initiates in winter, suggesting that some of the mechanisms would be valid even during quiescent phases. Ice surface velocity at mountain glaciers and ice sheets typically exhibits the greatest acceleration from spring to early summer, followed by deceleration in mid-summer to fall, and is slowest in winter. These short-term velocity changes are attributed to subglacial slip associated with water pressure changes that occur because of the seasonal variability of

  13. Evolution of surge levels inside of the Seine Bay : application to Johanna and Xynthia storms

    Science.gov (United States)

    Laborie, Vanessya; Sergent, Philippe; Hissel, François

    2014-05-01

    Within the Technical Commission for the Study and the Evaluation of Maritime Submersions in the Seine Estuary (CteeSMES), whose aim is to improve the collective knowledge on physical processes related to maritime surge levels, a numerical model of the Seine Estuary based on TELEMAC2D has been constructed to study the evolution of surge levels from the ocean to the harbour area of Le Havre and, in particular, evaluate the amplification of the global signal and the apparition of seiches inside René Coty's basin. The bathymetry of the model were partially provided by Le Havre and Rouen Harbours for the north-east part of the model. The numerical model was calibrated on JOHANNA and XYNTHIA storm events, which respectively occurred in March 2008 and in February 2010. Tide propagation was firstly calibrated through the test of several tide models used at the maritime boundary and a change of the friction coefficient on the bottom. Concerning the tide calibration, numerical results were compared with the predicted tide provided at Le Havre by two softwares : PREDIT and REFMAR (SHOM). To calibrate the global signal (tide + surge levels), measurements available on ten outputs of the Seine Estuary and provided by ports of Le Havre and Rouen were used to optimize the coefficient for wind influence. Winds and pressure fields were CFSR data. Once the numerical model of the Seine Bay had been calibrated both for tide and surge levels, it has been possible to draw the evolution of surge levels from the ocean to Le Havre (quai Meunier) and then to compare the signal obtained inside René Coty's basin. Consistently with measurements, numerical results show the apparition of an oscillating signal which adds to the signal at the entry of the Harbour. At the moment, the amplification is under-estimated, and results have to be improved to represent properly the process of the seiche inside the port, near the François Ier lock.

  14. Towards improved storm surge models in the northern Bay of Bengal

    Science.gov (United States)

    Krien, Y.; Testut, L.; Islam, A. K. M. S.; Bertin, X.; Durand, F.; Mayet, C.; Tazkia, A. R.; Becker, M.; Calmant, S.; Papa, F.; Ballu, V.; Shum, C. K.; Khan, Z. H.

    2017-03-01

    The northern Bay of Bengal is home to some of the deadliest cyclones recorded during the last decades. Storm surge models developed for this region significantly improved in recent years, but they still fail to predict patterns of coastal flooding with sufficient accuracy. In the present paper, we make use of a state-of-the art numerical modeling system with improved bathymetric and topographic data to identify the strengths, weaknesses, and to suggest areas for improvement of current storm surge models in this area. The new model is found to perform relatively well in reproducing waves characteristics and maximum water levels for the two extreme cyclones studied here: Phailin (2013) and Sidr (2007). The wave setup turns out to be small compared to the wind-driven surge, although it still plays a significant role for inland flooding. Relatively large tide-surge interactions mainly due to shallow water effects are also evidenced by the model. These findings plead in favor of further efforts to improve the representation of the bathymetry, especially in the nearshore area, and the implementation of models including tides and radiation stresses explicitly. The main limit of the model is its inability to predict the detailed patterns of coastal flooding satisfactorily. The reason lies mainly in the fact that topographic data also need to be further improved. In particular, a good knowledge of embankments characteristics (crest elevation and their condition) is found to be of primary importance to represent inland flooding correctly. Public authorities should take urgent action to ensure that better data are available to the scientific community, so that state-of-the-art storm surge models reaching a sufficiently high level of confidence can be used for emergency preparedness and to implement mitigation strategies in the northern Bay of Bengal.

  15. Revealing glacier flow and surge dynamics from animated satellite image sequences: examples from the Karakoram

    Science.gov (United States)

    Paul, F.

    2015-11-01

    Although animated images are very popular on the internet, they have so far found only limited use for glaciological applications. With long time series of satellite images becoming increasingly available and glaciers being well recognized for their rapid changes and variable flow dynamics, animated sequences of multiple satellite images reveal glacier dynamics in a time-lapse mode, making the otherwise slow changes of glacier movement visible and understandable to the wider public. For this study, animated image sequences were created for four regions in the central Karakoram mountain range over a 25-year time period (1990-2015) from freely available image quick-looks of orthorectified Landsat scenes. The animations play automatically in a web browser and reveal highly complex patterns of glacier flow and surge dynamics that are difficult to obtain by other methods. In contrast to other regions, surging glaciers in the Karakoram are often small (10 km2 or less), steep, debris-free, and advance for several years to decades at relatively low annual rates (about 100 m a-1). These characteristics overlap with those of non-surge-type glaciers, making a clear identification difficult. However, as in other regions, the surging glaciers in the central Karakoram also show sudden increases of flow velocity and mass waves travelling down glacier. The surges of individual glaciers are generally out of phase, indicating a limited climatic control on their dynamics. On the other hand, nearly all other glaciers in the region are either stable or slightly advancing, indicating balanced or even positive mass budgets over the past few decades.

  16. Utilizing Land:Water Isopleths for Storm Surge Model Development in Coastal Louisiana

    Science.gov (United States)

    Siverd, C. G.; Hagen, S. C.; Bilskie, M. V.; Braud, D.; Peele, H.; Twilley, R.

    2016-12-01

    In the Mississippi River Delta (MRD) Land:Water (L:W) isopleths (Gagliano et al., 1970, 1971) can be used to better understand coastal flood risk from hurricanes than simple estimates of land loss (Twilley et al., 2016). The major goal of this study is to develop a methodology that utilizes L:W isopleths to simplify a detailed present day storm surge model of coastal Louisiana. A secondary goal is to represent marsh fragmentation via L:W isopleths for modeling (for example) storm surge. Isopleths of L:W were derived for the year 2010 and include 1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99% (1% being mostly water and 99% being mostly land). Thirty-six models were developed via permutations of two isopleths selected with no repetition between 1% and 99%. The selected two isopleths result in three polygons which represent "open water/transition", "marsh", and "land". The ADvaced CIRCulation (ADCIRC) code (Luettich and Westerink, 2006) was used to perform storm surge simulations. Hydrologic basins, specifically Hydrologic Unit Code 12 (HUC12s), were used to quantify the water surface elevation, depth, volume, area and retention time across south Louisiana for each storm simulation and to provide a basin by basin comparison for the detailed model vs. simplified model results. This methodology aids in identifying the simplified model that most closely resembles the detailed model. It can also be used to develop comparable storm surge models for historical eras prior to the advent of modern remote sensing technology for the purpose of storm surge analysis throughout time.

  17. 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.

  18. Nursing students’ knowledge about arrest rhythms and their treatment

    Directory of Open Access Journals (Sweden)

    Aikaterini Kyrgianidou

    2014-04-01

    Full Text Available Cardiovascular diseases are one of the leading causes of death worldwide. Knowledge of health professionals for the arrest rhythms, is considered particularly important for the early recognition and proper treatment. Aim: The purpose of the present study was to assess the knowledge of nursing students on arrest rhythms and how to treat them. Material and Methods: The sample studied included 151 students from the Department of Nursing A' (n = 60, 40% and B' (n = 91, 60%, TEI of Athens, of whom 83% (n=125 were women and 17% (n=26 were men with a mean age of 23 years. Data collection was performed with specially designed questionnaire, that apart from demographics and students’ education level, it included ten questions about arrest rhythms’ knowledge and also self-assessment questions of their level of knowledge. The data were analyzed with the SPSS package v.19, using the criteria t-Test and χ2. Results: Of all the participants in the research, 95% (n = 144 did not answer correctly more than 6 questions from a total of 10. The students of the Department of Nursing A’ recognized with greater accuracy the arrest rhythms (p = 0.003. Those studying in lower semester acknowledged best the arrest rhythms (p = 0.002. Students who had recently attended course in basic or advanced resuscitation recognized best the arrest rhythms (p = 0.006. Older students knew better right treatment of the arrest rhythms (p = 0.037. Also, students who had attended the course of cardiac nursing in the last year, knew better the right treatment (p <0.001. Finally, the level of self-assessment was in line with the actual level of knowledge of students (p = 0.05. Conclusions: Continuous attendance of courses, education on certified programs and refresh courses help to maintain a good level of knowledge for longer periods.

  19. Prediction of cardiac arrest recurrence using ensemble classifiers

    Indian Academy of Sciences (India)

    NACHIKET TAPAS; TUSHAR LONE; DAMODAR REDDY; VENKATANARESH KUPPILI

    2017-07-01

    Inability of a heart to contract effectually or its failure to contract prevents blood from circulating efficiently, causing circulatory arrest or cardiac arrest or cardiopulmonary arrest. The unexpected cardiac arrest is medically referred to as sudden cardiac arrest (SCA). Poor survival rate of patients with SCA is one of themost ubiquitous health care problems today. Recent studies show that heart-rate-derived features can act as early predictors of SCA. Addition of angiographic and electrophysiological features can increase the robustness of the prediction system. Early warning has the capability of saving many lives. Risk of recurrent terminal cardiac arrest is high for out-of-hospital survivors. Foregoing studies indicate that recurrent cardiac events are time dependent and, while in clinical follow-up, are highly probable, predominantly in early phase. In this paper, we observe the changing risk of and changing influence of various clinical, angiographic and electrophysiological parameters on subsequent cardiac arrest recurrence with time. Various medical and synthetic datasets such as ECG dataset from PhysioNet, Pima Indian Diabetes dataset from UCI Machine Learning Repository and gene expression dataset from GEO are used, which are unique as compared with related works. Various classifiers such as LogitBoost with simple regression function, random forest and multilayer perceptron are used for recurrence risk prediction. Collection of these classifiers together forms the ensemble classifiers. Classifiers are compared based on various measures like accuracy and precision. Based on the classification, risk scores are calculated using logistic regression with backward elimination. The proposed method is used for final risk estimation. The same datasets are used for risk score calculation model development. Experimental results are found to be encouraging.

  20. The stringent response and cell cycle arrest in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Daniel J Ferullo

    2008-12-01

    Full Text Available The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes upon arrest. Nucleoids of these cells are decondensed; in the absence of the ability to synthesize ppGpp, nucleoids become highly condensed, similar to that seen after treatment with the translational inhibitor chloramphenicol. After induction of the stringent response, while regions corresponding to the origins of replication segregate, the termini remain colocalized in wild-type cells. In contrast, cells arrested by rifampicin and cephalexin do not show colocalized termini, suggesting that the stringent response arrests chromosome segregation at a specific point. Release from starvation causes rapid nucleoid reorganization, chromosome segregation, and resumption of replication. Arrest of replication and inhibition of colony formation by ppGpp accumulation is relieved in seqA and dam mutants, although other aspects of the stringent response appear to be intact. We propose that DNA methylation and SeqA binding to non-origin loci is necessary to enforce a full stringent arrest, affecting both initiation of replication and chromosome segregation. This is the first indication that bacterial chromosome segregation, whose mechanism is not understood, is a step that may be regulated in response to environmental conditions.