WorldWideScience

Sample records for periods pressure buildup

  1. Applying Petroleum the Pressure Buildup Well Test Procedure on Thermal Response Test—A Novel Method for Analyzing Temperature Recovery Period

    Directory of Open Access Journals (Sweden)

    Tomislav Kurevija

    2018-02-01

    Full Text Available The theory of Thermal Response Testing (TRT is a well-known part of the sizing process of the geothermal exchange system. Multiple parameters influence the accuracy of effective ground thermal conductivity measurement; like testing time, variable power, climate interferences, groundwater effect, etc. To improve the accuracy of the TRT, we introduced a procedure to additionally analyze falloff temperature decline after the power test. The method is based on a premise of analogy between TRT and petroleum well testing, since the origin of both procedures lies in the diffusivity equation with solutions for heat conduction or pressure analysis during radial flow. Applying pressure build-up test interpretation techniques to borehole heat exchanger testing, greater accuracy could be achieved since ground conductivity could be obtained from this period. Analysis was conducted on a coaxial exchanger with five different power steps, and with both direct and reverse flow regimes. Each test was set with 96 h of classical TRT, followed by 96 h of temperature decline, making for almost 2000 h of cumulative borehole testing. Results showed that the ground conductivity value could vary by as much as 25%, depending on test time, seasonal period and power fluctuations, while the thermal conductivity obtained from the falloff period provided more stable values, with only a 10% value variation.

  2. History matching of transient pressure build-up in a simulation model using adjoint method

    Energy Technology Data Exchange (ETDEWEB)

    Ajala, I.; Haekal, Rachmat; Ganzer, L. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany); Almuallim, H. [Firmsoft Technologies, Inc., Calgary, AB (Canada); Schulze-Riegert, R. [SPT Group GmbH, Hamburg (Germany)

    2013-08-01

    The aim of this work is the efficient and computer-assisted history-matching of pressure build-up and pressure derivatives by small modification to reservoir rock properties on a grid by grid level. (orig.)

  3. Change in surface SP caused by pressure buildup observed at the Nigorikawa geothermal area; Nigorikawa chiiki ni okeru atsuryoku buildup ji no shizen den`i henka

    Energy Technology Data Exchange (ETDEWEB)

    Yasukawa, K; Yano, Y; Matsushima, N; Ishido, T [Geological Survey of Japan, Tsukuba (Japan); Takahashi, M; Suzuki, I; Aoyama, K; Kuwano, T

    1996-10-01

    To examine the effect of change of subsurface flow system on the surface SP (self potential), SP measurements were carried out before and after the pressure buildup and drawdown during the periodic inspection at Nigorikawa area. Relation between the SP distribution and the observed data was also examined by 2-D numerical simulation. Tendency was found that the SP increased gradually with the production near the production well, decreased during the pressure buildup, and increased again during the drawdown. There were some points having the reverse tendency in the surrounding area. Behavior during the pressure buildup and drawdown was not clear. The resistivity near the ground surface was low ranging between 2 and 5 ohm/m within the Nigorikawa basin. The variation of SP was not so large when compared with the measuring error. The SP profiles on the secondary section passing in the center of caldera at the production stop and at one week after the production start were well corresponded with the profiles under natural conditions which were reproduces using the 2-D model. It was considered that the SP profile before the production stop was affected by the production. 12 refs., 6 figs., 1 tab.

  4. The Effect of Sloshing on a Tank Pressure Build-up Unit

    OpenAIRE

    Banne, Håvard Bolstad

    2017-01-01

    This thesis work has aimed to identify how sloshing will affect a liquefied natural gas (LNG) fuel tank. The physical nature of LNG means it needs to be kept cooled and pressurized in order to remain in a liquid state. By implementing a pressure build-up unit (PBU) it is possible to pressurize the tank vaporizing the tank’s contents, for the vapour then to return to tank in a loop, building pressure in the process. A tank pressure build-up unit has been built in the laboratory ...

  5. Prediction of moisture migration and pore pressure build-up in concrete at high temperatures

    International Nuclear Information System (INIS)

    Ichikawa, Y.; England, G.L.

    2004-01-01

    Prediction of moisture migration and pore pressure build-up in non-uniformly heated concrete is important for safe operation of concrete containment vessels in nuclear power reactors and for assessing the behaviour of fire-exposed concrete structures. (1) Changes in moisture content distribution in a concrete containment vessel during long-term operation should be investigated, since the durability and radiation shielding ability of concrete are strongly influenced by its moisture content. (2) The pressure build-up in a concrete containment vessel in a postulated accident should be evaluated in order to determine whether a venting system is necessary between liner and concrete to relieve the pore pressure. (3) When concrete is subjected to rapid heating during a fire, the concrete can suffer from spalling due to pressure build-up in the concrete pores. This paper presents a mathematical and computational model for predicting changes in temperature, moisture content and pore pressure in concrete at elevated temperatures. A pair of differential equations for one-dimensional heat and moisture transfer in concrete are derived from the conservation of energy and mass, and take into account the temperature-dependent release of gel water and chemically bound water due to dehydration. These equations are numerically solved by the finite difference method. In the numerical analysis, the pressure, density and dynamic viscosity of water in the concrete pores are calculated explicitly from a set of formulated equations. The numerical analysis results are compared with two different sets of experimental data: (a) long-term (531 days) moisture migration test under a steady-state temperature of 200 deg. C, and (b) short-term (114 min) pressure build-up test under transient heating. These experiments were performed to investigate the moisture migration and pressure build-up in the concrete wall of a reactor containment vessel at high temperatures. The former experiment simulated

  6. Optimal Pile Arrangement for Minimizing Excess Pore Water Pressure Build-Up

    DEFF Research Database (Denmark)

    Barari, Amin; Saadati, Meysam; Ibsen, Lars Bo

    2013-01-01

    Numerical analysis of pile group in a liquefiable soil was considered to investigate the influence of pile spacing on excess pore pressure distribution and liquefaction potential. The analysis is conducted using a two-dimensional plain strain finite difference program considering a nonlinear...... constitutive model for sandy soil, strength and stiffness reduction, and pile-soil interaction. The Mohr-Coulomb constitutive model coupled with Byrne pore pressure build-up model have been employed in the analysis. Numerical analysis results show that pile groups have significant influence on the dynamic...... response of sandy soil as they reduce the amount of excess pore pressure development during seismic shaking and may even prevent liquefaction....

  7. Process and equipment for pressure build-up in nuclear reactor fuel rods

    International Nuclear Information System (INIS)

    Heer, W.F.; Carli, E.V. de.

    1976-01-01

    The equipment makes possible the build-up of inert gas pressure in a filled and closed fuel can, i.e. in a complete fuel rod. Handling is simple, it is suitable for mass production and only causes low processing costs. The quality, e.g. the degree of purity of the contents of the rod, remains unchangedin processing. The equipment consists of a vacuum-tight space, into which the equally vacuum tight fuel rod is introduced, and can be fixed so that its position can be reproduced unmistakeably. The vacuum space contains a connection for the inert gases and a laser arrangement. After inserting a fuel rod into the facility, this is evacuated and the fuel can has a hole bored in it by a laser beam. After fast equalisation of pressure, an inert gas at the required pressure is introduced into the chamber and the fuel rod. After the filling process is completed, the fuel can is closed again with the same laser beam. The quality of the seal obtained, i.e the leak-tightness of the fuel can, can be checked after reduction of the inert gas pressure and before taking out the fuel rod, by repeated evacuation of the chamber. Laser light energies between 13,000 and 110,000 Joule/sq cm are sufficient. Optimum results were obtained for a Zircaloy fuel can with about 52,000 Joule/sq cm. (TK) [de

  8. The Influence of Seal Properties on Pressure Buildup and Leakage of Carbon Dioxide from Sequestration Reservoirs (Invited)

    Science.gov (United States)

    Benson, S. M.; Chabora, E.

    2009-12-01

    The transport properties of seals, namely permeability, relative permeability, and capillary pressure control both migration of carbon dioxide and brine through the seal. Only recently has the the importance of brine migration emerged as key issue in the environmental performance of carbon dioxide sequestration projects. In this study we use numerical simulation to show that brine migration through the seal can be either advantageous or deleterious to the environmental performance of a carbon dioxide sequestration project. Brine migration through the seal can lower the pressure buildup in the storage reservoir, thereby reducing the risk of leakage or geomechanical stresses on the seal. On the other hand, if the seal is penetrated by a permeable fault it can lead to focused flow up a fault, which could lead to brine migration into drinking water aquifers. We also show that as the carbon dioxide plume grows, brine flow undergoes a complex evolution from upward flow to downward flows driven by countercurrent migration of carbon dioxide and brine in the seal and capillary pressure gradients at the base of the seal. Finally, we discuss desirable attributes seals, taking into account both carbon dioxide and brine migration through the seal. In particular, identifying seals that provide an effective capillary barrier to block the flow of carbon dioxide while allowing some brine migration through the seal can help to control pressure buildup and allow more efficient utilization of a sequestration reservoir. This could be particularly important in those settings that may be limited by the maximum allowable pressure buildup.

  9. Influence of Pressure Build-Up Time of Compression Chamber on Improving the Operation Frequency of a Single-Piston Hydraulic Free-Piston Engine

    Directory of Open Access Journals (Sweden)

    Hai-bo Xie

    2013-01-01

    Full Text Available A single-piston hydraulic free-piston engine with a two-cylinder four-stroke diesel engine as its driver is introduced. It takes the free-piston assembly a certain time to move after the pressure in the compression chamber starts to increase. The time difference between the pressure increasing and the piston starting to move is defined as the pressure build-up time. The characteristics of the pressure build-up time and its influence on the performance of the free-piston engine are introduced and analyzed. Based on the basic law of dynamics of the free-piston assembly, the parameters which influence the pressure build-up time are analyzed. And then improvement and optimization are proposed to shorten the pressure build-up time.

  10. Model Study of the Pressure Build-Up during Subcutaneous Injection

    DEFF Research Database (Denmark)

    Thomsen, Maria; Hernandez Garcia, Anier; Mathiesen, Joachim

    2014-01-01

    In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws...

  11. Considerations on pressure build-up in deep geological repositories for radioactive waste

    International Nuclear Information System (INIS)

    Beer, Hans-Frieder

    2015-01-01

    Gas formation caused by corrosion of metals is a pivotal point with respect to the safety analysis of deep geological repositories. Solid corrosion products are formed unavoidably during the gas formation. The volumes of these solid corrosion products are multiples of the original waste volume. These solid corrosion products are chemically extremely stable and result in a pressure increase inside the repository. This pressure is considerably higher than that of the overlaying rock. The question that arises is, why this aspect is not considered in the consulted documents.

  12. SOIL-AIR PERMEABILITY MEASUREMENT WITH A TRANSIENT PRESSURE BUILDUP METHOD

    Science.gov (United States)

    An analytical solution for transient pressure change in a single venting well was derived from mass conservation of air, Darcy's law of flow in porous media, and the ideal gas law equation of state. Slopes of plots of Pw2 against ln (t+Δt)/Δt similar to Homer's plot were used to ...

  13. Modelling Venting and Pressure Build-up in a 18650 LCO Cell during Thermal Runaway (ABSTRACT)

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian; White, Ralph

    Li-ion batteries are a very popular type of electric storage devices that possess high energy density when compared to the other battery chemistries. Due to this property, when operating under abusive conditions such as high ambient temperature, the batteries can experience thermal runaway, which...... may lead to fires and explosions. To prevent this, it is therefore important to model thermal runaway considering different events such as venting and the pressure development inside the battery cell, which makes the main purpose of this paper. A model consisting of the different decomposition....... By fitting the activation energies, and measuring experimentally the mass of the ejecta during thermal runaway, the model is compared and validated against an extensive experiment performed by Golukbov et al. [1] during oven heating. When analysing the results, it is found that by including the venting...

  14. Effect of ultraviolet light irradiation period on bond strengths between fiber-reinforced composite post and core build-up composite resin.

    Science.gov (United States)

    Asakawa, Yuya; Takahashi, Hidekazu; Iwasaki, Naohiko; Kobayashi, Masahiro

    2014-01-01

    The aim of the present study was to characterize the effects of the ultraviolet light (UV) irradiation period on the bond strength of fiber-reinforced composite (FRC) posts to core build-up resin. Three types of FRC posts were prepared using polymethyl methacrylate, urethane dimethacrylate, and epoxy resin. The surfaces of these posts were treated using UV irradiation at a distance of 15 mm for 0 to 600 s. The pull-out bond strength was measured and analyzed with the Dunnett's comparison test (α=0.05). The bond strengths of the post surfaces without irradiation were 6.9 to 7.4 MPa; those after irradiation were 4.2 to 26.1 MPa. The bond strengths significantly increased after 15 to 120-s irradiation. UV irradiation on the FRC posts improved the bond strengths between the FRC posts and core build-up resin regardless of the type of matrix resin.

  15. Ultrasound periodic inspections of reactor pressure vessels

    International Nuclear Information System (INIS)

    Haniger, L.

    1980-01-01

    Two versions are described of ultrasonic equipment for periodic inspections of reactor pressure vessels. One uses the principle of exchangeable programmators with solid-state logic while the other uses programmable logic with semiconductor memories. The equipment is to be used for inspections of welded joints on the upper part of the V-1 reactor pressure vessel. (L.O.)

  16. Investigations with respect to pressure build-up in 200 l drums with supercompacted low level waste (LLW)

    International Nuclear Information System (INIS)

    Kroth, K.; Lammertz, H.

    1988-04-01

    In the drum storage facilities of various nuclear power stations, ballooning effects have recently been observed on a limited number of 200 l drums filled with hypercompacted mixed LLW. The ballooning of the drums lid and bottom is due to internal overpressure caused by gas formation in the waste. The internal drum pressures and the composition of the drum gases were measured on a considerable number of 200 l drums. Hydrogen, formed by chemical reactions between the waste components, was identified as the pressure generating gas. The reasons for the hydrogen formation were investigated on both real and simulated wastes. (orig.) [de

  17. First evaluation of experimental results describing pressure buildup and hydrogen distribution, obtained by experimental series E11

    International Nuclear Information System (INIS)

    Holzbauer, H.; Wolf, L.; Valencia, L.

    1990-01-01

    The beginning of the core meltdown process in the reactor pressure vessel, with a supposed release position for hydrogen in the upper part of the containment, is simulated, and the influence of the plant geometry on the distribution process is studied. In addition, the release point is shifted to the lower containment area, additional hydrogen production owing to the interaction between concrete and melt is taken into account, and sump boiling is simulated. The experimental program covers analytical investigations in the form of blind post-calculations. (DG) [de

  18. Simulation of the build-up phase of a high voltage low pressure gas discharge using Monte-Carlo-methods

    International Nuclear Information System (INIS)

    Niessen, W.

    1990-02-01

    In this report the simulation of a Pseudospark predischarge between anode and cathode using Monte-Carlo-Methods is described. In the early phase of the discharge electric and magnetic self-fields can be neglected. The model is based on a discharge between two infinitely extended capacitor plates. Eleven different collision reactions and two electrode surface effects are taken into account. A Fortran program was developed that computes the built-up of the discharge in time and space. A specially of the code is, that not only electrons and ions are taken into account, but also fast neutral atoms and molecules. Three pairs of diode-length and voltage were investigated at different pressures: 350 kV/5.0 cm, 30 kV/10.0 cm and 6.9 kV/0.7 cm. The working gas was hydrogen. The computations included: The Paschen-curve, the time evolution of the current densities of the electrons at the anode and the ions at the cathode, the space- and time-dependent particle densities, the time-dependent energy distributions of the different particle species, the relative number of the different collision reactions. (orig./HSI) [de

  19. On the transient pressure build-up in the full pressure safety shell of watercooled nuclear reactors after a loss of coolant accident

    International Nuclear Information System (INIS)

    Mansfeld, G.

    1979-08-01

    The thermo-and fluid-dynamic processes in a multichamber full pressure safety containment during a loss of coolant accident have been investigated. Comparison of the calculations carried out with the computer programs, in which ZOCO VI was used as being representative of similar programs, with the experimental results pointed out discrepancies in the determination of time dependent pressure, pressure difference and temperature curves. This led to the development of a new theoretical model and a program COFLOW which pays particular attention to the fluid dynamic processes in the initial phase of a loss of coolant accident. It can also be used to determine the maximum containment pressure towards the end of a loss of coolant accident. Comparison of the COFLOW results with experiments has shown that COFLOW provides a model and a procedure by which the physical processes in a multichamber full pressure safety containment can be simulated satisfactorily

  20. Plastics control paraffin buildup

    Energy Technology Data Exchange (ETDEWEB)

    1965-06-01

    Paraffin buildup in producing oil wells has been virtually eliminated by the use of plastic-coated sucker rods. The payout of the plasticing process is generally reached in less than a year, and the paraffin buildup may be inhibited for 10 yr or longer. Most of the plants applying plastic coatings to sucker rods are now fully automated, though a few still offer the hand-sprayed coating that some operators prefer. The several steps involved are described. The ideal plastic for the job is resistant to chemicals at high and low temperatures, flexible, has good adhesion, abrasion resistance, impact resistance, and a smooth glossy finish. The phenol aldehyde and epoxy resins presently offered by the industry fulfill these specifications very well; the multicoating and multibaking techniques improve their performance. Due to wide variations in the severity of the paraffin problem from one oil field to another, there is no general rule to estimate the possible savings from using plastic-coated sucker rods. The process, however, does appear to do a remarkable job in controlling paraffin buildup wherever it is a problem in producing oil by pump.

  1. Mars base buildup scenarios

    International Nuclear Information System (INIS)

    Blacic, J.D.

    1985-01-01

    Two surface base build-up scenarios are presented in order to help visualize the mission and to serve as a basis for trade studies. In the first scenario, direct manned landings on the Martian surface occur early in the missions and scientific investigation is the main driver and rationale. In the second scenario, early development of an infrastructure to exploite the volatile resources of the Martian moons for economic purposes is emphasized. Scientific exploration of the surface is delayed at first, but once begun develops rapidly aided by the presence of a permanently manned orbital station

  2. Am-241 buildup in nematode organisms

    International Nuclear Information System (INIS)

    Martyushov, V.Z.; Tarasov, O.V.

    1990-01-01

    The process of Am-241 intake into earthworm organisms from chernozem leached in their presence in soil contaminated with this radionuclide is studied. The data on Am-241 buildup values during long-time radionuclide intake into earthworm organisms from soil are given. It s shown that Am-241 buildup in earthworm organisms do not exceed its concentration in soil for the whole observation period (as Am-241 presents in soil in state unavailable for animals). Intensive extraction of the radionuclide from the organisms is observed when earthworm contacts with soil are stopped

  3. Pressure Build-up and Decay in Acid Gas Injection Operations in Reefs in the Zama Field, Canada, and Implications for CO2 Storage

    International Nuclear Information System (INIS)

    Pooladi-Darvish, M.; Hong, H.; Pooladi-Darvish, M.; Bachu, S.

    2011-01-01

    The objective of this paper is to examine reasons for pressure rise in the Zama X2X pool in northwestern Alberta, Canada, that was used for acid gas disposal, and whether subsequent pressure decay was a result of pressure dissipation into a larger aquifer. The Zama X2X pool, approximately 1 km 2 in size, is connected to four other nearby pools through a common underlying aquifer. Pressure analysis for all the pools indicates that they are in good hydraulic communication. Initial pressure in the Zama X2X pool was approximately 15 MPa. Pressure declined first during oil production, stabilizing at around 10 MPa in the early 1970's, after which started to increase such that it reached 26 MPa in 1986. Subsequently, pressure declined reaching 22 MPa by 1995 just prior to starting injection of acid gas (80% CO 2 and 20% H 2 S). The operator injected acid gas at lower rates and wellhead pressures than those licensed by the regulatory agency. Despite significant production of water and hydrocarbons, the pressure in the Zama X2X pool continued to be higher than the initial reservoir pressure by more than 5 MPa, such that disposal operations were suspended in late 1998. Oil production continued all this time until 2002. Numerical simulations using CMG-IMEM and corresponding sensitivity studies reported in this paper show that disposal of more than 1 million m 3 of water between 1970 and 1988 and again in 1992-1993 in the adjacent Zama YY pool, which is in good hydrodynamic communication with the Zama X2X pool through the aquifer below the oil column, is the main reason for the high pressures observed in the Zama X2X pool. Sensitivity studies indicate that pressure decay in the X2X pool was due to fluid production. The study indicates that while pressure rise has been caused by hydraulic communication between the X2X and YY pools through the common aquifer, the aquifer was not of large volume to allow dissipation of the pressure. In addition to the case study, the implications

  4. Considerations on pressure build-up in deep geological repositories for radioactive waste; Betrachtungen zum Druckaufbau in einem geologischen Tiefenlager fuer radioaktive Abfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Hans-Frieder [Paul Scherrer Institut, Villigen-PSI (Switzerland)

    2015-07-01

    Gas formation caused by corrosion of metals is a pivotal point with respect to the safety analysis of deep geological repositories. Solid corrosion products are formed unavoidably during the gas formation. The volumes of these solid corrosion products are multiples of the original waste volume. These solid corrosion products are chemically extremely stable and result in a pressure increase inside the repository. This pressure is considerably higher than that of the overlaying rock. The question that arises is, why this aspect is not considered in the consulted documents.

  5. An advanced analytical solution for pressure build-up during CO2 injection into infinite saline aquifers: The role of compressibility

    Science.gov (United States)

    Wu, Haiqing; Bai, Bing; Li, Xiaochun

    2018-02-01

    Existing analytical or approximate solutions that are appropriate for describing the migration mechanics of CO2 and the evolution of fluid pressure in reservoirs do not consider the high compressibility of CO2, which reduces their calculation accuracy and application value. Therefore, this work first derives a new governing equation that represents the movement of complex fluids in reservoirs, based on the equation of continuity and the generalized Darcy's law. A more rigorous definition of the coefficient of compressibility of fluid is then presented, and a power function model (PFM) that characterizes the relationship between the physical properties of CO2 and the pressure is derived. Meanwhile, to avoid the difficulty of determining the saturation of fluids, a method that directly assumes the average relative permeability of each fluid phase in different fluid domains is proposed, based on the theory of gradual change. An advanced analytical solution is obtained that includes both the partial miscibility and the compressibility of CO2 and brine in evaluating the evolution of fluid pressure by integrating within different regions. Finally, two typical sample analyses are used to verify the reliability, improved nature and universality of this new analytical solution. Based on the physical characteristics and the results calculated for the examples, this work elaborates the concept and basis of partitioning for use in further work.

  6. Pore pressure buildup and soil stress relaxation in monopile foundations of offshore wind converters; Porenwasserdruckaufbau und Bodenentfestigung um Pfahlgruendungen von Offshore-Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Cuellar, Pablo; Baessler, Matthias; Georgi, Steven; Ruecker, Werner [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany). Fachbereich 7.2 Ingenieurbau

    2012-09-15

    For the installation of wind turbines in the offshore environment and their foundation in the seabed it is customary to employ large-diameter steel piles, either in monopile or multi-pile configurations (jacket, tripod, etc..). The effects of cyclic lateral loading on the offshore piles and particularly the possibility of a progressive accumulation of residual pore water pressure within the saturated embedding soil are discussed in this article. Here it is shown that this can lead to significant changes of their behaviour under external loading, which can potentially compromise the foundation's stability or serviceability. Furthermore, some of the singular effects arising during a realistic storm of moderate magnitude as well as their potential for transient damages to the foundation's stiffness are addressed in the paper. For the investigation of these phenomena the authors have employed a coupled bi-phasic analytical model of the offshore foundation. The constitutive model employed for the seabed, in the frame of the theory of Generalized Plasticity, can reproduce some complex features of cyclic soil behaviour such as the tendency for a progressive densification under cyclic loading, which is responsible for the soil liquefaction phenomena in undrained conditions. Finally, some implications and specific recommendations for the design of offshore monopiles in the frame of the limit states are provided. (orig.)

  7. FISCAL PRESSURE IN ROMANIA IN THE CURRENT PERIOD

    Directory of Open Access Journals (Sweden)

    HARALAMBIE GEORGE ALIN

    2014-05-01

    Full Text Available Determination of optimal fiscal pressure threshold is difficult to determine given the conditions under which the state must ensure a balance between the goals to be funded, on account of the tax levies, and need to be available to the economic operators and the general public a sufficient portion of the income to continue their work. Practice has shown that an excessive taxation results in reducing budget revenue due to tax fraud and abstinence of tax payers. They will find ingenious ways to evade the payment of tax liabilities by non-taxable matter or by establishing their domicile for tax purposes in a country with low taxation.

  8. Quasi-periodic fluctuations of atmospheric pressure and cosmic rays observed in the stratosphere

    International Nuclear Information System (INIS)

    Kodama, Masahiro; Abe, Toshiaki; Sakai, Takasuke; Kato, Masato; Kogami, Shinichi.

    1976-01-01

    Quasi-periodicities of barometric pressure and cosmic ray intensity, with 5.5-minute period and one hour persistency, have been observed by means of a high-precision barometer and a large plastic scintillation counter in a balloon at an altitude of --18 km over the Pacific Ocean. From characteristics of such short period fluctuations, it is suggested that the observed pressure fluctuation may possibly be caused by the internal atmospheric gravity wave whose amplitude and wave length are --30 m and --30 km respectively. (auth.)

  9. Numerical Investigation of Periodically Unsteady Pressure Field in a High Power Centrifugal Diffuser Pump

    Directory of Open Access Journals (Sweden)

    Ji Pei

    2014-05-01

    Full Text Available Pressure fluctuations are the main factors that can give rise to reliability problems in centrifugal pumps. The periodically unsteady pressure characteristics caused by rotor-stator interaction have been investigated by CFD calculation in a residual heat removal pump. Side chamber flow effect is also considered for the simulation to accurately predict the flow in whole flow passage. The pressure fluctuation results in time and frequency domains were considered for several typical monitoring points in impeller and diffuser channels. In addition, the pressure fluctuation intensity coefficient (PFIC based on standard deviation was defined on each grid node for entire space and impeller revolution period. The results show that strong pressure fluctuation intensity can be found in the gap between impeller and diffuser. As a source, the fluctuation can spread to the upstream and downstream flow channels as well as the side chamber channels. Meanwhile, strong pressure fluctuation intensity can be found in the discharge tube of the circular casing. In addition, the obvious influence of operational flow rate on the PFIC distribution can be found. The analysis indicates that the pressure fluctuations in the aspects of both frequency and intensity can be used to comprehensively evaluate the unsteady pressure characteristics in centrifugal pumps.

  10. Hydrostatic pressure and strain effects in short period InN/GaN superlattices

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede

    2012-01-01

    The electronic structures of short-period pseudomorphically grown superlattices (SLs) of the form mInN/nGaN are calculated and the band gap variation with the well and the barrier thicknesses is discussed including hydrostatic pressure effects. The calculated band gap shows a strong dependence...... strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....

  11. From detached to attached buildup complexes

    DEFF Research Database (Denmark)

    Rafaelsen, B.; Elvebakk, G.; Andreassen, K.

    2008-01-01

    -like ridges and possibly areas with restricted circulation. Warm-water carbonate buildups, forming ridges and isolated mounds, occur in the Gipsdalen Group (latest Serpukhovian-mid-Sakmarian), where they initially grew in a detached platform setting. The carbonate buildups are several tens of kilometres long...... deposition and buildup growth bridged the detached platform with the attached platform. In the Bjarmeland Group (Lower Permian) 0.35-4.8 km wide, 1.5-27 km long and 60-420 m thick cool-water bryozoan-dominated straight, sinuous and continuous carbonate ridges or atoll-like ridges are located on top...

  12. Fission gas pressure build-up and fast-breeder economy; Accumulation de la pression des gaz de fission et economie des reacteurs surgenerateurs a neutrons rapides; Nakoplenie davleniya gazov produktov deleniya i ehkonomika reaktorov-razmnozhitelej na bystrykh nejtronakh; Aumento de la presion de los gases de fision y economia de los reactores reproductores rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Engelmann, P [Kernforschungszentrum, Karlsruhe (Germany)

    1962-03-15

    Fuel-cycle costs and doubling time of fast-breeder reactors are strongly affected by the fuel-burn-up obtainable. Use of oxide or carbide fuel offers the possibility of reaching a burn-up of 100 000 MWd/t. In fuel-clad elements, a limiting factor is the fission-gas-pressure build-up. At the high burn-up considered, an appreciable fraction of the fission gases gets into the pores and thus contributes to the pressure on the can. Starting from the known fission-product yields and decay chains, gas production and pressure build-up have been calculated. Three physical models have been employed in calculating the pressure acting upon the can : the gas is contained either in interconnected pores, in separate pores, or in a central hole. The pressure-dependence upon free volume (fuel density) and temperature will be discussed. Cans made of high-strength materials as Ineonel-X and molybdenum could stand the fission-gas pressure at operating temperatures. Unfortunately, these materials have higher absorption cross-sections than stainless steel. Results of a multi-group calculation are given, showing the effect of using these can materials and of decreasing the fuel density on critical mass and breeding ratio in small and medium-size breeders. (author) [French] Le cout du cycle de combustible et la periode de doublement des reacteurs surgenerateurs a neutrons rapides dependent etroitement du taux de combustion. En utilisant pour combustible un oxyde ou un carbure, on peut atteindre un taux de combustion de 100 000 MW j/t. Avec des combustibles gaines, l'accumulation de la pression des gaz de fission est un facteur limitatif. Pour le fort taux de combustion envisage, une fraction non negligeable des gaz de fission penetre dans les interstices et contribue ainsi a la pression sur la gaine. A partir des rendements en produits de fission et des chaines de desintegration connus, l'auteur a calcule la production de gaz et l'accumulation de pression. Pour calculer la pression

  13. Momentum management strategy during Space Station buildup

    Science.gov (United States)

    Bishop, Lynda; Malchow, Harvey; Hattis, Philip

    1988-01-01

    The use of momentum storage devices to control effectors for Space Station attitude control throughout the buildup sequence is discussed. Particular attention is given to the problem of providing satisfactory management of momentum storage effectors throughout buildup while experiencing variable torque loading. Continuous and discrete control strategies are compared and the effects of alternative control moment gyro strategies on peak momentum storage requirements and on commanded maneuver characteristics are described.

  14. The Pressure-Temperature Regime of Iraq during the Period of 1948–2013

    Directory of Open Access Journals (Sweden)

    Yu.P. Perevedentsev

    2016-03-01

    Full Text Available We have considered spatiotemporal changes in the pressure-temperature regime at the territory of Iraq and Middle Eastern countries, which is limited by the following geographical coordinates: 27.5–37.5° N, 37.5–50.0° E. The initial data have been obtained from NCEP/NCAR reanalysis in the nodes of 2.5° × 2.5° grids, as well as from the indices of atmospheric circulation during the period of 1948–2013. Statistical processing of the material and construction of the linear trends and composites have allowed to reveal the dynamics of changes in the air temperature and pressure, its dependence on fluctuations in the atmospheric circulation. A tendency has been revealed towards a decrease in the temperature during the cold period and its increase during the warm period. Deviations (anomalies of the distribution of actual temperature and atmospheric pressure from the climatological norm have been estimated. Maps of temperature and pressure distribution in the regions have been created.

  15. Development of Extended Period Pressure-Dependent Demand Water Distribution Models

    Energy Technology Data Exchange (ETDEWEB)

    Judi, David R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mcpherson, Timothy N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-20

    Los Alamos National Laboratory (LANL) has used modeling and simulation of water distribution systems for N-1 contingency analyses to assess criticality of water system assets. Critical components considered in these analyses include pumps, tanks, and supply sources, in addition to critical pipes or aqueducts. A contingency represents the complete removal of the asset from system operation. For each contingency, an extended period simulation (EPS) is run using EPANET. An EPS simulates water system behavior over a time period, typically at least 24 hours. It assesses the ability of a system to respond and recover from asset disruption through distributed storage in tanks throughout the system. Contingencies of concern are identified as those in which some portion of the water system has unmet delivery requirements. A delivery requirement is defined as an aggregation of water demands within a service area, similar to an electric power demand. The metric used to identify areas of unmet delivery requirement in these studies is a pressure threshold of 15 pounds per square inch (psi). This pressure threshold is used because it is below the required pressure for fire protection. Any location in the model with pressure that drops below this threshold at any time during an EPS is considered to have unmet service requirements and is used to determine cascading consequences. The outage area for a contingency is the aggregation of all service areas with a pressure below the threshold at any time during the EPS.

  16. Numerical analysis of pressure and porosity evolution in lava domes during periodic degassing conditions

    Science.gov (United States)

    Hyman, D.; Bursik, M. I.; Pitman, E. B.

    2017-12-01

    The collapse or explosive breakup of growing and degassing lava domes presents a significant hazard due to the generation of dense, mobile pyroclastic flows as well as the wide dispersal of dense ballistic blocks. Lava dome stability is in large part governed by the balance of transport and storage of gas within the pore space. Because pore pressurization reduces the effective stress within a dome, the transient distribution of elevated gas pressure is critically important to understanding dome break up. We combine mathematical and numerical analyses to gain a better understanding of the temporal variation in gas flow and storage within the dome system. In doing so, we develop and analyze new governing equations describing nonlinear gas pressure diffusion in a deforming dome with an evolving porosity field. By relating porosity, permeability, and pressure, we show that the flux of gas through a dome is highly sensitive to the porosity distribution and viscosity of the lava, as well as the timescale and magnitude of the gas supply. The numerical results suggest that the diffusion of pressure and porosity variations play an integral role in the cyclic growth and destruction of small domes.The nearly continuous cycles of lava dome growth, pressurization, and failure that have characterized the last two decades of eruptive history at Volcán Popocatépetl, Mexico provide excellent natural data with which to compare new models of transient dome pressurization. At Popocatépetl, periodic pressure increases brought on by changes in gas supply into the base of the dome may play a role in its cyclic growth and destruction behavior. We compare our model of cyclic pressurization with lava dome survival data from Popocatépetl. We show that transient changes in pore pressure explain how small lava domes evolve to a state of criticality before explosion or collapse. Additionally, numerical analyses presented here suggest that short-term oscillations cannot arise within the dome

  17. Programmable - logic equipment for ultrasound periodic inspections of reactor pressure vessels

    International Nuclear Information System (INIS)

    Haniger, L.

    1980-01-01

    Two alternatives are presented of programmable logic corresponding to the 2nd generation of the apparatus for performing periodic ultrasonic inspections of power reactor pressure vessels and a solution is outlined of inspecting the circumferential weld on the pressure vessel head. The apparatus will allow using any measuring head taken into consideration for operational inspection. Command words are taken from a punched type reader. Czechoslovak made RAM memories are used. The algorithm of instrument function is supposed to be controlled by a microprocessor as soon as necessary preconditions for this technology are created in Czechoslovakia

  18. Effects of periodic atmospheric pressure variation on radon entry into buildings

    Science.gov (United States)

    Tsang, Y. W.; Narasimhan, T. N.

    1992-06-01

    Using a mathematical model, we have investigated the temporal variations of radon entry into a house basement in the presence of time-dependent periodic variations of barometric pressure as well as a persistent small steady depressurization within the basement. The tool for our investigation is an integral finite difference numerical code which can solve for both diffusive and advective flux of radon in the soil gas which is treated as a slightly compressible fluid. Two different boundary conditions at the house basement are considered: (1) a dirt floor basement so that diffusion is equally or more important than advective transport, and (2) an "impermeable" cement basement except for a 1-cm-wide crack near the perimeter of the basement floor; in which case, advective transport of radon flux dominates. Two frequencies of barometric pressure fluctuation with representative values of amplitudes, based on a Fourier decomposition of barometric pressure data, were chosen in this study: one with a short period of 0.5 hour with pressure amplitude of 50 Pa, the other a diurnal variation with a period of 24 hours with the typical pressure amplitude of 250 Pa. For a homogeneous soil medium with soil permeability to air between 10-13 and 10-10 m2, we predict that the barometric fluctuations increase the radon entry into the basement by up to 120% of the steady radon inflow into the basement owing to a steady depressurization of 5 Pa. If soil permeability heterogeneity is present, such as the presence of a thin layer of higher permeability aggregate immediately below the basement floor, radon flux due to atmospheric pumping is further increased. Effects of pressure pumping on radon entry are also compared to diffusion-only transport when the steady depressurization is absent. It is found that contribution to radon entry is significant for the basement crack configuration. In particular, for pressure pumping at 0.5-hour period and for a homogeneous medium of permeability of 10

  19. Effect of surface treatments on radiation buildup in steam generators

    International Nuclear Information System (INIS)

    Asay, R.H.; Pick, M.E.; van Melsen, C.

    1991-11-01

    Test coupons of typical PWR materials of construction were prepared using a number of pretreatments to minimize radiation buildup. The coupons were then exposed to primary coolant at the Doel-2 PWR in Belgium. The exposure periods for the coupons ranged from one to three fuel cycles. After removal from the primary system, doserate and gamma spectroscopy measurements were made to determine the radioactivity levels on the coupons. Varying levels of success were achieved for the preconditioning techniques tested. Electropolishing alone provided some degree of resistance to radiation buildup on the treated surface and electropolishing plus passivation was shown to be even better. Radiation buildup resistance of the palladium-coated coupons was poor; radiation levels on these coupons were even higher than on the untreated reference coupons. The poor performance of the palladium-coated coupons was possibly due to the method used to apply the coating. In contrast to palladium coating, very encouraging results were achieved with chromium plating plus passivation. Preliminary results show that this technique can inhibit activity deposition by as much as a factor of ten. 4 refs., 64 figs., 26 tabs

  20. The operative treatment of pressure sores in the pelvic region: A 10-year period overview.

    Science.gov (United States)

    Jósvay, János; Klauber, András; Both, Béla; Kelemen, Péter B; Varga, Zsombor Z; Pesthy, Pál Cs

    2015-07-01

    Pelvic region pressure sores often develop following spinal cord injury. Surgery is often necessary for long standing, large-sized pressure sores not responding to conservative treatment. Authors analyze their results of a 10-year period, and identify factors contributing to the reduction of the recurrence rate. A total of 119 pressure sores were operated on 98 patients in two institutions during a 10-year period (1 January 2003 to 31 December 2012). The encountered perioperative complications are summarized, and the recurrence rate is analyzed with a patient follow-up questionnaire. We experienced 15 perioperative complications (12.6%). All complications were fully resolved by conservative treatment. Fifty-eight returned patient replies were processed. The average follow-up time after surgery was 5.2 years. The recurrence rate was 5.47%. The strict adherence to surgical indications, full patient compliance, specialized pre- and post-operative patient care, our routinely used preferred surgical method, all contribute to a low post-operative complication rate, long-term flap survival, and an extended recurrence free period.

  1. Dose determination on buildup region using photodiodes

    International Nuclear Information System (INIS)

    Khoury, H.J.; Lopes, F.J.; Melo, F. de A.

    1989-01-01

    A clinical dosemeter using photodiode BPW-34 was developed, allowing the determination of dose on buildup region. The measures were made with X-rays beam of linear accelerator and with gamma radiation of cobalt 60. The results were compared with others made in a ionization chamber. (C.G.C.) [pt

  2. Photon buildup factors of some chemotherapy drugs.

    Science.gov (United States)

    Kavaz, Esra; Ahmadishadbad, Nader; Özdemir, Yüksel

    2015-02-01

    Everyday more and more people are diagnosed with some form of cancer. Some are treatable with chemotherapy alone, while others need radiotherapy and occasionally surgery. Recently, concurrent administration of chemotherapy and radiotherapy has been increasingly used in cancer treatment, leading to improvements in survival as well as quality of life. Accordingly, interaction of chemotherapy drugs with radiation will be meaningful to examine. In the present study, gamma ray energy absorption and exposure of buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for some chemotherapy drugs in the energy range 0.015-15 MeV, and for penetration depths up to 40 mean free path (mfp). The generated energy absorption (EABF) and exposure buildup factors (EBF) of chemotherapy drugs have been studied as a function of penetration depth and incident photon energy. The significant variations in EABF and EBF for chemotherapy drugs have been observed at the moderate energy region. It has been concluded that the buildup of photons is less in azathioprine and is more in vinblastine compared with other drugs. Buildup factors investigated in the present work could be useful in radiation dosimetry and therapy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  3. BWR radiation buildup control with ionic zinc

    International Nuclear Information System (INIS)

    Marble, W.J.; Wood, C.J.; Leighty, C.E.; Green, T.A.

    1986-01-01

    In 1983 a hypothesis was disclosed which suggested that the presence of ionic zinc in the reactor water of the BWR could reduce radiation buildup. This hypothesis was developed from correlations of plant data, and subsequently, from laboratory experiments which demonstrated clearly that ionic zinc inhibits the corrosion of stainless steel. The benefits of zinc addition have been measured at the Vallecitos Nuclear Center under and EPRI/GE project. Experimentation and analyses have been performed to evaluate the impact of intentional zinc addition on the IGSCC characteristics of primary system materials and on the performance of the nuclear fuel. It has been concluded that no negative effects are expected. The author conclude that the intentional addition of ionic zinc to the BWR reactor water at a concentration of approximately 10 ppb will provide major benefits in controlling the Co-60 buildup on primary system stainless steel surfaces. The intentional addition of zinc is now a qualified technique for use in BWRs

  4. Electron-Cloud Build-Up: Summary

    International Nuclear Information System (INIS)

    Furman, M.A.

    2007-01-01

    I present a summary of topics relevant to the electron-cloud build-up and dissipation that were presented at the International Workshop on Electron-Cloud Effects 'ECLOUD 07' (Daegu, S. Korea, April 9-12, 2007). This summary is not meant to be a comprehensive review of the talks. Rather, I focus on those developments that I found, in my personal opinion, especially interesting. The contributions, all excellent, are posted in http://chep.knu.ac.kr/ecloud07/

  5. Families of periodic orbits in Hill's problem with solar radiation pressure: application to Hayabusa 2

    Science.gov (United States)

    Giancotti, Marco; Campagnola, Stefano; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

    2014-11-01

    This work studies periodic solutions applicable, as an extended phase, to the JAXA asteroid rendezvous mission Hayabusa 2 when it is close to target asteroid 1999 JU3. The motion of a spacecraft close to a small asteroid can be approximated with the equations of Hill's problem modified to account for the strong solar radiation pressure. The identification of families of periodic solutions in such systems is just starting and the field is largely unexplored. We find several periodic orbits using a grid search, then apply numerical continuation and bifurcation theory to a subset of these to explore the changes in the orbit families when the orbital energy is varied. This analysis gives information on their stability and bifurcations. We then compare the various families on the basis of the restrictions and requirements of the specific mission considered, such as the pointing of the solar panels and instruments. We also use information about their resilience against parameter errors and their ground tracks to identify one particularly promising type of solution.

  6. Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans

    NARCIS (Netherlands)

    Silvani, A.; Calandra-Buonaura, G.; Johnson, B.D.; Helmond, N. van; Barletta, G.; Cecere, A.G.; Joyner, M.J.; Cortelli, P.

    2017-01-01

    The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological

  7. Research and development activities of the High Pressure Physics Division for the period March 1991-September 1993

    International Nuclear Information System (INIS)

    Godwal, B.K.; Bhadauria, Y.S.

    1993-01-01

    The research and development activities of the High Pressure Physics Division during the period March 1991 to September 1993 are reported in the form of abstracts and titles of the publications. The report is organised into two sections: (A) High Pressure Physics Section, and (B) Seismology Section. A list of staff members of the two sections is also given. (author)

  8. Investigation of the effects of time periodic pressure and engpotential gradients on viscoelastic fluid flow in circular narrow confinements

    DEFF Research Database (Denmark)

    Nguyen, Trieu; van der Meer, Devaraj; van den Berg, Albert

    2017-01-01

    -Boltzmann equation, together with the incompressible Cauchy momentum equation under no-slip boundary conditions for viscoelastic fluid in the case of a combination of time periodic pressure-driven and electro-osmotic flow. The resulting solutions allow us to predict the electrical current and solution flow rate...... conversion applications. We also found that time periodic electro-osmotic flow in many cases is much stronger enhanced than time periodic pressure-driven flow when comparing the flow profiles of oscillating PDF and EOF in micro-and nanochannels. The findings advance our understanding of time periodic......In this paper we present an in-depth analysis and analytical solution for time periodic hydrodynamic flow (driven by a time-dependent pressure gradient and electric field) of viscoelastic fluid through cylindrical micro-and nanochannels. Particularly, we solve the linearized Poisson...

  9. Efflux Performance of Submicron Particles in Packed Bed under Periodic Pressure Conditions; Shuki atsuho ni yoru juten sonai sabumikuron biryushi no ryushutsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Ping, Z; Iritani, E; Murase, T [Nagaya Univ. Nagoya (Japan). Department of Chemical Engineering

    1997-09-01

    Permeation experiments of ultrapure water were conducted under periodic pressure conditions using a packed bed obtained by dispersing submicron particles of polymethyl methacrylate (PMMA) uniformly into a packed bed of particles of White Alundum. It is clearly demonstrated that washing performance under periodic pressure conditions where the permeation pressure is applied periodically is improved dramatically, compared with that under constant pressure conditions. It is also shown that the effect of periodic pressure operation is especially noticeable in the initial stage of the pressurizing period, and that a pressurizing time smaller than 2 min is very effective under conditions examined in this study. 4 figs.

  10. Build-up and management of transuranium

    International Nuclear Information System (INIS)

    Uematsu, Kunihiko

    1984-01-01

    About 17,000,000 kW is generated by nuclear power station at present and this figure correspond to 20 % of total power generation in Japan, and is expected to increase year after year. Following the increase of power generation, build-up of Transuraium from nuclear power station will increase as a matter of course. In 2,000 AD; the build-up of Pu and TPu is expected to reach up to 200 T(TPu = 24 T). Effective management of TPu build-up is now an urgent problem Recycling of Pu and TPu including LWR-Pu recycling, ATR-Pu recycling and FBR-Pu recycling were investigated. In LWR-Pu recycling, recycling quantities of Pu and TPu, and generation of power increase following the repetition of recycling. In ATR-Pu recycling, the increase of TPu following recycling is more remakable than that of LWR-Pu recycling. On the contrary, in FBR-Pu recycling, TPu decreases following the repetition of recycling. The decrease of TPu is thought to be caused by extinction effect in FBR. All of these recycling are suitable for the utilization of Pu, but FBR-Pu recycling is most effective for utilization of Pu and decrease of TPu. Accordingly, when LWR or ATR recycling is applied, Pu shall be transferred to FBR after 1 - 2 recycling. For long-term management of TPu, recycling is not sufficient and some positive method such as oxtinction by strong neutron source like proton linear accelerator is necessary. Fundamental researches on nuclear fuel cycle, nuclide separation method and extinction process of TPu must be carried out. (Ishimitsu, A.)

  11. Buildup of radioxenon isotopes in MOX-assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Gniffke, Thomas; Kirchner, Gerald [Carl Friedrich von Weizsaecker-Centre for Science and Peace Research, Hamburg (Germany)

    2015-07-01

    Radioxenon is the main tracer for detection of nuclear tests conducted underground under the verification regime of the Comprehensive Nuclear Test Ban Treaty (CTBT). Since radioxenon is emitted by civilian sources too, like commercial nuclear reactors, source discrimination is still an important issue. Inventory calculations are necessary to predict which xenon isotopic ratios are built up in a reactor and how they differ from those generated by a nuclear explosion. The screening line actually used by the CTBT Organization for source discrimination is based on calculations for uranium fuel of various enrichments used in pressurized water reactors (PWRs). The usage of different fuel, especially mixed U/Pu oxide (MOX) assemblies with reprocessed plutonium, may alter the radioxenon signature of civilian reactors. In this talk, calculations of the radioxenon buildup in a MOX-assembly used in a commercial PWR are presented. Implications for the CTBT verification regimes are discussed and open questions are addressed.

  12. Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods

    Science.gov (United States)

    Noda, Takahiro; Nakakita, Kazuyki; Wakahara, Masaki; Kameda, Masaharu

    2018-06-01

    Image measurement using pressure-sensitive paint (PSP) is an effective tool for analyzing the unsteady pressure field on the surface of a body in a low-speed air flow, which is associated with wind noise. In this study, the surface pressure fluctuation due to the tonal trailing edge (TE) noise for a two-dimensional NACA 0012 airfoil was quantitatively detected using a porous anodized aluminum PSP (AA-PSP). The emission from the PSP upon illumination by a blue laser diode was captured using a 12-bit high-speed complementary metal-oxide-semiconductor (CMOS) camera. The intensities of the captured images were converted to pressures using a standard intensity-based method. Three image-processing methods based on the fast Fourier transform (FFT) were tested to determine their efficiency in improving the signal-to-noise ratio (SNR) of the unsteady PSP data. In addition to two fundamental FFT techniques (the full data and ensemble averaging FFTs), a technique using the coherent output power (COP), which involves the cross correlation between the PSP data and the signal measured using a pointwise sound-level meter, was tested. Preliminary tests indicated that random photon shot noise dominates the intensity fluctuations in the captured PSP emissions above 200 Hz. Pressure fluctuations associated with the TE noise, whose dominant frequency is approximately 940 Hz, were successfully measured by analyzing 40,960 sequential PSP images recorded at 10 kfps. Quantitative validation using the power spectrum indicates that the COP technique is the most effective method of identification of the pressure fluctuation directly related to TE noise. It is possible to distinguish power differences with a resolution of 10 Pa^2 (4 Pa in amplitude) when the COP was employed without use of another wind-off data. This resolution cannot be achieved by the ensemble averaging FFT because of an insufficient elimination of the background noise.

  13. Dynamic pressure probe response tests for robust measurements in periodic flows close to probe resonating frequency

    Science.gov (United States)

    Ceyhun Şahin, Fatma; Schiffmann, Jürg

    2018-02-01

    A single-hole probe was designed to measure steady and periodic flows with high fluctuation amplitudes and with minimal flow intrusion. Because of its high aspect ratio, estimations showed that the probe resonates at a frequency two orders of magnitude lower than the fast response sensor cut-off frequencies. The high fluctuation amplitudes cause a non-linear behavior of the probe and available models are neither adequate for a quantitative estimation of the resonating frequencies nor for predicting the system damping. Instead, a non-linear data correction procedure based on individual transfer functions defined for each harmonic contribution is introduced for pneumatic probes that allows to extend their operating range beyond the resonating frequencies and linear dynamics. This data correction procedure was assessed on a miniature single-hole probe of 0.35 mm inner diameter which was designed to measure flow speed and direction. For the reliable use of such a probe in periodic flows, its frequency response was reproduced with a siren disk, which allows exciting the probe up to 10 kHz with peak-to-peak amplitudes ranging between 20%-170% of the absolute mean pressure. The effect of the probe interior design on the phase lag and amplitude distortion in periodic flow measurements was investigated on probes with similar inner diameters and different lengths or similar aspect ratios (L/D) and different total interior volumes. The results suggest that while the tube length consistently sets the resonance frequency, the internal total volume affects the non-linear dynamic response in terms of varying gain functions. A detailed analysis of the introduced calibration methodology shows that the goodness of the reconstructed data compared to the reference data is above 75% for fundamental frequencies up to twice the probe resonance frequency. The results clearly suggest that the introduced procedure is adequate to capture non-linear pneumatic probe dynamics and to

  14. Influence of periodic heartbeat reversal and abdominal movements on hemocoelic and tracheal pressure in resting blowflies Calliphora vicina.

    Science.gov (United States)

    Wasserthal, Lutz Thilo

    2012-01-15

    In Calliphoridae and Drosophilidae, the dorsal vessel (heart and aorta with associated venous channels) is the only connection between the thorax and the abdomen. Hemolymph oscillates between the compartments by periodic heartbeat reversal, but both the mechanism and its influence on hemocoelic and tracheal pressure have remained unclear. The pumping direction of the heart regularly reverses, with a higher pulse rate during backward compared with forward pumping. A sequence of forward and backward pulse periods lasts approximately 34 s. Pulse rate, direction, velocity and the duration of heartbeat periods were determined by thermistor and electrophysiological measurements. For the first time, heartbeat-induced pressure changes were measured in the hemocoel and in the tracheal system of the thorax and the abdomen. The tracheal pressure changed from sub-atmospheric during backward heartbeat to supra-atmospheric during forward heartbeat in the thorax and inversely in the abdomen. The heartbeat reversals were coordinated with slow abdominal movements with a pumping stroke at the beginning of the forward pulse period. The pressure effect of the pumping stroke was visible only in the abdomen. Periodic hemolymph shift and abdominal movements resulted in pressure changes in the hemocoel and tracheal system alternating in the thorax and abdomen, suggesting an effect on respiratory gas exchange.

  15. Photoluminescence and pressure effects in short period InN/nGaN superlattices

    DEFF Research Database (Denmark)

    Staszczak, G.; Gorczyca, I.; Suski, T.

    2013-01-01

    Measurements of photoluminescence and its dependence on hydrostatic pressure are performed on a set of InN/nGaN superlattices with one InN monolayer and with different numbers of GaN monolayers. The emission energies, EPL, measured at ambient pressure, are close to the value of the band gap, Eg......, in bulk GaN, in agreement with other experimental findings. The pressure dependence of the emission energies, dEPL/dp, however, resembles that of the InN energy gap. Further, the magnitudes of both EPL and dEPL/dp are significantly higher than those obtained from ab-initio calculations for 1In...

  16. Effect of altered eating habits and periods during Ramadan fasting on intraocular pressure, tear secretion, corneal and anterior chamber parameters

    NARCIS (Netherlands)

    Kerimoglu, H.; Ozturk, B.; Gunduz, K.; Bozkurt, B.; Kamis, U.; Okka, M.

    Purpose To determine whether altered eating habits and periods, especially the pre-dawn meal, during Ramadan fasting have any significant effect on intraocular pressure (IOP), tear secretion, corneal and anterior chamber parameters. Methods IOP, basal tear secretion (BTS), reflex tear secretion

  17. Transition to chaos in periodically driven thermionic diodes at low pressure

    International Nuclear Information System (INIS)

    Klinger, T.; Timm, R.; Piel, A.

    1992-01-01

    The static I(U) characteristic of thermionic diodes at mbar pressures shows a large hysteresis, which describes the transition from the 'anode-glow-mode' (AGM), with essentially negative plasma potential, to the 'temperature-limited-mode' (TLM), with positive plasma potential. Many features of these modes are also found in magnetic-box discharges with filament cathodes at pressures of 10 -2 -10 -1 Pa. Although these two pressure regimes are basically different concerning the transport properties (diffusion vs. free streaming), the elementary processes that establish the AGM in the low pressure regime are very similar to the high pressure regime. Ions are produced in that part of the anode sheath where the potential exceeds the ionization energy. The production rate is enhanced by multiple reflections of electrons between the magnetic fields of the permanent magnet array at the anode and the repulsive potential of the cathode plasma. Although the mean free path for charge exchange or elastic collisions substantially exceeds the anode-cathode distance, some few ions are stopped and trapped within the potential well of the virtual cathode. This accumulation of ions forms a cathodic plasma, which is essentially at cathode potential. Plasma formation in the anode sheath is suppressed as long as the ion production time is larger than the ion transit time through the sheath. These model ideas are supported by 1d-Particle-in-cell simulations using a modified PDP1-code. The AGM is attractive for studies of nonlinear dynamics because of its feedback processes and oscillations, which occur close to the hysteresis point. (author) 7 refs., 3 figs

  18. CURRENT BUILDUP IN EMERGING SERPENTINE FLUX TUBES

    International Nuclear Information System (INIS)

    Pariat, E.; Masson, S.; Aulanier, G.

    2009-01-01

    The increase of magnetic flux in the solar atmosphere during active-region formation involves the transport of the magnetic field from the solar convection zone through the lowest layers of the solar atmosphere, through which the plasma β changes from >1 to <1 with altitude. The crossing of this magnetic transition zone requires the magnetic field to adopt a serpentine shape also known as the sea-serpent topology. In the frame of the resistive flux-emergence model, the rising of the magnetic flux is believed to be dynamically driven by a succession of magnetic reconnections which are commonly observed in emerging flux regions as Ellerman bombs. Using a data-driven, three-dimensional (3D) magnetohydrodynamic numerical simulation of flux emergence occurring in active region 10191 on 2002 November 16-17, we study the development of 3D electric current sheets. We show that these currents buildup along the 3D serpentine magnetic-field structure as a result of photospheric diverging horizontal line-tied motions that emulate the observed photospheric evolution. We observe that reconnection can not only develop following a pinching evolution of the serpentine field line, as usually assumed in two-dimensional geometry, but can also result from 3D shearing deformation of the magnetic structure. In addition, we report for the first time on the observation in the UV domain with the Transition Region and Coronal Explorer (TRACE) of extremely transient loop-like features, appearing within the emerging flux domain, which link several Ellermam bombs with one another. We argue that these loop transients can be explained as a consequence of the currents that build up along the serpentine magnetic field.

  19. Metal transfer and build-up in friction and cutting

    CERN Document Server

    Kuznetsov, V D

    1956-01-01

    Metal Transfer and Build-up in Friction and Cutting aims to systematize our knowledge of the metal build-up, to describe some of the investigations past and present carried out in SFTI (Tomsk), and to make an effort to explain a number of the phenomena in cutting, scratching, and sliding from the point of view of metal transfer theory. The book opens with a chapter on the temperature of the rubbing interface of two solids. This temperature is needed in order to elucidate the nature of the formation of a build-up in scratching, cutting, and sliding. Separate chapters follow on the seizure phen

  20. Adaptation to periodic pressure chamber hypoxia and its influence on systolic and diastolic functions in chronic heart failure

    Directory of Open Access Journals (Sweden)

    Dmitrieva М.К.

    2012-06-01

    Full Text Available Research objective is to determine the influence of adaptation method to periodic pressure chamber hypoxia on dynamics of systolic and diastolic functions of myocardium in patients with early stages of chronic heart failure. Materials and Methods: 100 men with post-infarction cardiosclerosis at the age of 40-65 years with I and IIA stages and l-ll functional classes (NYHA of chronic heart failure have been examined. Results: Positive dynamics of systolic and diastolic cardiac functions and other parameters of echocardioscopy under the influence of the hypoxic therapy in comparison with classical physical rehabilitation have been obtained. Furthermore, a more significant effect has been observed in patients with CHF IIA. Conclusion: Improvement in the geometry of the heart has proved that adaptation method to periodic pressure chamber hypoxia could be recommended for rehabilitation of patients with heart failure of early stages.

  1. Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans

    OpenAIRE

    Silvani, Alessandro; Calandra-Buonaura, Giovanna; Johnson, Blair D.; van Helmond, Noud; Barletta, Giorgio; Cecere, Anna G.; Joyner, Michael J.; Cortelli, Pietro

    2017-01-01

    The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological mechanisms that mediate the coupling between HP and SAP in response to different postures, we analyzed the cross-correlation functions between low-frequency HP and SAP fluctuations and estimated cBR...

  2. Avian predation pressure as a potential driver of periodical cicada cycle length

    Science.gov (United States)

    Walter E. Koenig; Andrew M. Liebhold

    2013-01-01

    The extraordinarily long life cycles, synchronous emergences at 13- or 17-year intervals, and complex geographic distribution of periodical cicadas (Magicicada spp.) in eastern North America are a long-standing evolutionary enigma. Although a variety of factors, including satiation of aboveground predators and avoidance of interbrood hybridization,...

  3. Radiography simulation based on exposure buildup factors for multilayer structures

    International Nuclear Information System (INIS)

    Marinkovic, Predrag; Pesic, Milan

    2009-01-01

    Monte Carlo techniques were usually used to study the effect of scattered photons on a radiographic X-ray image. Such approach is accurate, but computer time consuming. On the other hand, the exposure buildup factors can be used as approximate and efficient assessment to account for the scattering of X-rays. This method uses the known radiography parameters to find the resulting detector exposure due to both scattered and un-collided photons. A model for radiography simulation, based on X-ray dose buildup factor, is proposed. This model includes non-uniform attenuation in voxelized object of imaging (patient body tissue). Composition of patient body is considered as a multi-layer structure. Various empirical formulas exist for multi-layer structure calculations and they all calculate multi-layer buildup factors by combining single-layer buildup factors. The proposed model is convenient in cases when more exact techniques (like Monte Carlo) are not economical. (author)

  4. Synthesis of coesite nanocrystals from ethane bridged periodic mesoporous organosilica at low temperature and extreme pressure.

    Science.gov (United States)

    Liang, Zhili; Mohanty, Paritosh; Fei, Yingwei; Landskron, Kai

    2010-12-14

    Coesite nanocrystals have been synthesized from periodic mesoporous organosilica (PMO) with (CH(2))(2) bridges heated at 300 °C for 150 min and 12 GPa. The crystals are not sintered, single crystalline, and have diameters of ca. 100-300 nm. Below 300 °C, an amorphous non-porous organosilica glass was obtained. Heating above 300 °C at 12 GPa results in the rapid crystal growth and micron size coesite crystals were formed.

  5. An Empirical Model for Build-Up of Sodium and Calcium Ions in Small Scale Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    Subriyer Nasir

    2011-05-01

    Full Text Available A simple models for predicting build-up of solute on membrane surface were formulated in this paper. The experiments were conducted with secondary effluent, groundwater and simulated feed water in small-scale of RO with capacity of 2000 L/d. Feed water used in the experiments contained varying concentrations of sodium, calcium, combined sodium and calcium. In order to study the effect of sodium and calcium ions on membrane performance, experiments with ground water and secondary effluent wastewater were also performed. Build-up of salts on the membrane surface was calculated by measuring concentrations of sodium and calcium ions in feed water permeate and reject streams using Atomic Absorption Spectrophotometer (AAS. Multiple linear regression of natural logarithmic transformation was used to develop the model based on four main parameters that affect the build-up of solute in a small scale of RO namely applied pressure, permeate flux, membrane resistance, and feed concentration. Experimental data obtained in a small scale RO unit were used to develop the empirical model. The predicted values of theoretical build-up of sodium and calcium on membrane surface were found in agreement with experimental data. The deviation in the prediction of build-up of sodium and calcium were found to be 1.4 to 10.47 % and 1.12 to 4.46%, respectively.

  6. Guide to the periodic inspection of nuclear reactor steel pressure vessels

    International Nuclear Information System (INIS)

    1969-01-01

    This Guide is intended to provide general information and guidance to reactor owners or operators, inspection authorities, certifying authorities or regulatory bodies who are responsible for establishing inspection procedures for specific reactors or reactor types, and for the preparation of national codes or standards. The recommendations of the Guide apply primarily to water-cooled steel reactor vessels which are at a sufficiently early stage of design so that recommendations to provide accessibility for inspection can be incorporated into the early stages of design and inspection planning. However, much of the contents of the Guide are also applicable in part to vessels for other reactor types, such as gas-cooled, pressure-tube, or liquid-metal-cooled reactors, and also to some existing water-cooled reactors and reactors which are in advanced stage of design or construction. 46 refs, figs, 1 tab

  7. Effect of altered eating habits and periods during Ramadan fasting on intraocular pressure, tear secretion, corneal and anterior chamber parameters.

    Science.gov (United States)

    Kerimoglu, H; Ozturk, B; Gunduz, K; Bozkurt, B; Kamis, U; Okka, M

    2010-01-01

    To determine whether altered eating habits and periods, especially the pre-dawn meal, during Ramadan fasting have any significant effect on intraocular pressure (IOP), tear secretion, corneal and anterior chamber parameters. IOP, basal tear secretion (BTS), reflex tear secretion (RTS), and Pentacam measurements of 31 healthy volunteers were performed at 0800 and 1600 hours during Ramadan fasting and 1 month later during non-fasting period. Comparison of measurements between fasting and non-fasting periods at 0800 hours revealed significantly higher values for IOP (P=0.005), RTS (P=0.006), and BTS (P=0.014) during fasting. Conversely at 1600 hours, IOP was significantly lower during fasting (P=0.013) and no statistically significant difference was noted for RTS and BTS. IOP showed a diurnal variation of 2.45 mmHg (P<0.001) and BTS showed a 3.06 mm decrease (P=0.04) during the fasting period. No significant differences could be found in the corneal and anterior chamber parameters during fasting and non-fasting periods. Our results revealed that fluid loading at the pre-dawn meal during Ramadan fasting might increase the IOP and tear secretion in the early morning period and these values decrease remarkably at the end of 12 h of fasting due to dehydration.

  8. Estimating vertical and lateral pressures in periodically structured montmorillonite clay particles

    Directory of Open Access Journals (Sweden)

    Guillermo A. Narsilio

    2010-03-01

    Full Text Available Given a montmorillonitic clay soil at high porosity and saturated by monovalent counterions, we investigate the particle level responses of the clay to different external loadings. As analytical solutions are not possible for complex arrangements of particles, we employ computational micromechanical models (based on the solution of the Poisson-Nernst-Planck equations using the finite element method, to estimate counterion and electrical potential distributions for particles at various angles and distances from one another. We then calculate the disjoining pressures using the Van't Hoff relation and Maxwell stress tensor. As the distance between the clay particles decreases and double-layers overlap, the concentration of counterions in the micropores among clay particles increases. This increase lowers the chemical potential of the pore fluid and creates a chemical potential gradient in the solvent that generates the socalled 'disjoining' or 'osmotic' pressure. Because of this disjoining pressure, particles do not need to contact one another in order to carry an 'effective stress'. This work may lead towards theoretical predictions of the macroscopic load deformation response of montmorillonitic soils based on micromechanical modelling of particles.Dada uma argila montmorilonítica de alta porosidade e saturada por counteríons monovalentes, investigamos as respostas da argila ao nível de partículas para diferentes cargas externas. Como soluções analíticas não são possíveis para arranjos complexos de partículas, empregamos modelos computacionais micro-mecânicos (baseados na solução das equações de Poisson-Nernst-Planck, utilizando o método de elementos finitos, para estimar counteríons e distribuições de potencial elétrico para partículas em diversos ângulos e distâncias uma da outra. Nós então calculamos as pressões de separação usando a relação de Van't Hoff e a tensão de cisalhamento de Maxwell. À medida que a

  9. Task related doses in Spanish pressurized water reactors over the period 1988-1992

    Energy Technology Data Exchange (ETDEWEB)

    O`Donnell, P.; Labarta, T.; Amor, I. [Subdireccion de Proteccion Radiologica, Madrid (Spain)

    1995-03-01

    In order to evaluate in depth the collective dose trend and its correlation with the effectiveness of the practical application of the ALARA principle in Spanish nuclear facilities, and base the different policy lines to promote this criteria, the CSN has fullfilled an analysis of the task related doses data over the period 1988-1992. Previously, the CSN had required to the utilities the compilation of their refuelling outage collective dose from 1988 according with a predeterminate number of tasks, in order to have available a representative and retrospective set of data in an homogeneous way and coherent with the international data banks on occupational exposure in NPP, as the CEC and the NEA ones. The scope of this analysis was the following: first, the collective dose summaries for outage tasks and departments for PWR and for BWR, including the minimum, maximum and average dose (and statistics data) for 18 different refuelling outage tasks and 12 personal departments for each generation of each type of rector, the task and department related collective dose trends in each plant and in each generation, and second, the dose reduction techniques having been used during that period in each plant and the relative level of adoption. In this presentation the main results and conclusions of the first part of the study are reviewed for PWR.

  10. The effect of lateral decubitus position on nocturnal intraocular pressure over a habitual 24-hour period in healthy adults.

    Science.gov (United States)

    Hao, Jie; Zhen, Yi; Wang, Hao; Yang, Diya; Wang, Ningli

    2014-01-01

    To investigate the effect of lateral decubitus position (LDP) on nocturnal intraocular pressure (IOP) and the effect of LDP on 24-hour habitual IOP pattern in healthy subjects. Intraocular pressure was measured every 2-hours using an Accupen Applanation Tonometer (Accutome, USA). During the diurnal period (7:30 am, 9:30 am, 11:30 am, 1:30 pm, 3:30 pm, 5:30 pm, 7:30 pm, and 9:30 pm), IOP was measured in the sitting position under bright light (500-1000 lux) after the subjects had been seated for 5 min. The nocturnal IOP was measured in the supine position, right LDP, and left LDP, with randomized sequences, under dim light (hour habitual IOP patterns were obtained according to the nocturnal position (supine, right LDP and left LDP) for either eye. Phour period, the effect of LDP on habitual IOP pattern was not statistically significant, although the mean nocturnal IOP and the diurnal-nocturnal IOP change for the right and the left eye in the LDP pattern was slightly higher than that in the sitting-supine pattern. Significant nocturnal IOP differences existed between the dependent eye and the supine, but did not occur consistently for all time points. Over a 24-hour period, the effect of LDP on habitual IOP pattern was not statistically significant in healthy subjects.

  11. Effect of Reynolds number, turbulence level and periodic wake flow on heat transfer on low pressure turbine blades.

    Science.gov (United States)

    Suslov, D; Schulz, A; Wittig, S

    2001-05-01

    The development of effective cooling methods is of major importance for the design of new gas turbines blades. The conception of optimal cooling schemes requires a detailed knowledge of the heat transfer processes on the blade's surfaces. The thermal load of turbine blades is predominantly determined by convective heat transfer which is described by the local heat transfer coefficient. Heat transfer is closely related to the boundary layer development along the blade surface and hence depends on various flow conditions and geometrical parameters. Particularly Reynolds number, pressures gradient and turbulence level have great impact on the boundary layer development and the according heat transfer. Therefore, in the present study, the influence of Reynolds number, turbulence intensity, and periodic unsteady inflow on the local heat transfer of a typical low pressure turbine airfoil is experimentally examined in a plane cascade.

  12. Weaning from non-invasive positive pressure ventilation: Experience with progressive periods of withdraw

    Directory of Open Access Journals (Sweden)

    C. Damas

    2008-01-01

    Full Text Available Background: In recent years non-invasive ventilation (NIV as become a valuable therapeutic option in exacerbations of patients with chronic pulmonary obstructive disease. Although widely used there is a paucity of information on weaning from NIV. Objectives: We aimed to describe the performance of a weaning protocol based on progressive periods of NIV withdraw. Methods: During a one year period we performed NIV in 78 patients with acute exacerbation of chronic respiratory failure. Weaning was considered in patients with 24 hours without acidosis and respiratory rate less than 25 cycles per minute. Weaning was performed as following: during the first 24 hours in each 3 hours, one hour without NIV (except during night period, in the second day in each 3 hours, two hours without NIV (except during night period and in the third day NIV was used during the night period. Results: Sixty five patients began the weaning protocol. Mean NIV time was 120,9 hours (17 to 192 hours. No adverse effects were recorded in patients who began the weaning protocol. All patients completed the weaning protocol with no re-institution of NIV or invasive ventilation during hospitalization. Conclusions: We report an excellent weaning success rate of NIV in patients with acute severe exacerbation of CRF. Although our weaning protocol required 72 hours, our results suggest that strategies based on periods with and with-out NIV are effective. Weather similar less time consuming weaning strategies are effective, merits investigation. Resumo: Introdução: Nos últimos anos, a ventilação não invasiva (VNI tornou-se numa opção terapêutica válida nas exacerbações agudas de doentes com doença pulmonar crónica obstrutiva. No entanto, apesar de muito utilizada, existe muito pouca informação sobre o desmame deste modo ventilatório. Objectivos: Descrever um protocolo de desmame baseado em períodos progressivos de descontinuação de VNI. Métodos: Durante um ano foram

  13. Evaluation of pressure drop across area changes during blowdown. Quarterly progress report for period ending June 30, 1976

    International Nuclear Information System (INIS)

    Weisman, J.

    1976-11-01

    Transient pressure drops across abrupt area changes are being determined in a series of blowdown experiments. These tests are being conducted with Freon 113 as the test fluid in a well instrumented apparatus. During this period, test runs were obtained with the first abrupt expansion test section. Test data from two typical runs are included in this report. Additional progress was made in developing the computer programs which were to be used in analyzing this data but funding of this analytical effort has been suspended

  14. Chemical composition dependence of exposure buildup factors for some polymers

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Tejbir [Department of Physics, S.D.D.I.E.T., Barwala, District Panchkula, Haryana 134 118 (India)], E-mail: tejbir.s@rediffmail.com; Kumar, Naresh [Department of Physics, Lovely Professional University, Phagwara 144 402 (India)], E-mail: naresh20dhiman@yahoo.com; Singh, Parjit S. [Department of Physics, Punjabi University, Patiala 147 002 (India)], E-mail: dr_parjit@hotmail.com

    2009-01-15

    Exposure buildup factors for some polymers such as poly-acrylo-nitrile (PAN), poly-methyl-acrylate (PMA), poly-vinyl-chloride (PVC), synthetic rubber (SR), tetra-fluro-ethylene (Teflon) have been computed using the G.P. fitting method in the energy range of 0.015-15.0 MeV, up to the penetration of 40 mean free paths (mfp). The variation of exposure buildup factors for all the selected polymers with incident photon energy at the fixed penetration depths has been studied, mainly emphasizing on chemical composition (equivalent atomic number) of the selected polymers. It has been observed that for the lower penetration depths (below 10 mfp), the exposure buildup factor decreases with the increase in equivalent atomic number of the selected polymers at all the incident photon energies. However, at the penetration depth of 10 mfp and incident photon energy above 3 MeV, the exposure buildup factor becomes almost independent of the equivalent atomic number of the selected polymers. Further, above the fixed penetration depth of 15 mfp of the selected polymers and above the incident photon energy of 3 MeV, reversal in the trend has been observed, i.e., the exposure buildup factor increases with the increase in equivalent atomic number.

  15. Chemical composition dependence of exposure buildup factors for some polymers

    International Nuclear Information System (INIS)

    Singh, Tejbir; Kumar, Naresh; Singh, Parjit S.

    2009-01-01

    Exposure buildup factors for some polymers such as poly-acrylo-nitrile (PAN), poly-methyl-acrylate (PMA), poly-vinyl-chloride (PVC), synthetic rubber (SR), tetra-fluro-ethylene (Teflon) have been computed using the G.P. fitting method in the energy range of 0.015-15.0 MeV, up to the penetration of 40 mean free paths (mfp). The variation of exposure buildup factors for all the selected polymers with incident photon energy at the fixed penetration depths has been studied, mainly emphasizing on chemical composition (equivalent atomic number) of the selected polymers. It has been observed that for the lower penetration depths (below 10 mfp), the exposure buildup factor decreases with the increase in equivalent atomic number of the selected polymers at all the incident photon energies. However, at the penetration depth of 10 mfp and incident photon energy above 3 MeV, the exposure buildup factor becomes almost independent of the equivalent atomic number of the selected polymers. Further, above the fixed penetration depth of 15 mfp of the selected polymers and above the incident photon energy of 3 MeV, reversal in the trend has been observed, i.e., the exposure buildup factor increases with the increase in equivalent atomic number

  16. Energy absorption build-up factors in teeth

    International Nuclear Information System (INIS)

    Manjunatha, H.C.; Rudraswamy, B.

    2012-01-01

    Geometric progression fitting method has been used to compute energy absorption build-up factor of teeth [enamel outer surface, enamel middle, enamel dentin junction towards enamel, enamel dentin junction towards dentin, dentin middle and dentin inner surface] for wide energy range (0.015-15 MeV) up to the penetration depth of 40 mean free path. The dependence of energy absorption build-up factor on incident photon energy, penetration depth, electron density and effective atomic number has also been studied. The energy absorption build-up factors increases with the penetration depth and electron density of teeth. So that the degree of violation of Lambert-Beer (I = I 0 e -μt ) law is less for least penetration depth and electron density. The energy absorption build-up factors for different regions of teeth are not same hence the energy absorbed by the different regions of teeth is not uniform which depends on the composition of the medium. The relative dose of gamma in different regions of teeth is also estimated. Dosimetric implication of energy absorption build-up factor in teeth has also been discussed. The estimated absorption build up factors in different regions of teeth may be useful in the electron spin resonance dosimetry. (author)

  17. Build-up dynamics of heavy metals deposited on impermeable urban surfaces.

    Science.gov (United States)

    Wicke, D; Cochrane, T A; O'Sullivan, A

    2012-12-30

    A method using thin boards (3 cm thick, 0.56 m(2)) comprising different paving materials typically used in urban environments (2 asphalt types and concrete) was employed to specifically investigate air-borne deposition dynamics of TSS, zinc, copper and lead. Boards were exposed at an urban car park near vehicular traffic to determine the rate of contaminant build-up over a 13-day dry period. Concentration profiles from simulated rainfall wash-off were used to determine contaminant yields at different antecedent dry days. Maximum contaminant yields after 13 days of exposure were 2.7 kg ha(-1) for TSS, 35 g ha(-1) zinc, 2.3 g ha(-1) copper and 0.4 g ha(-1) lead. Accumulation of all contaminants increased over the first week and levelled off thereafter, supporting theoretical assumptions that contaminant accumulation on impervious surfaces asymptotically approaches a maximum. Comparison of different surface types showed approximately four times higher zinc concentrations in runoff from asphalt surfaces and two times higher TSS concentrations in runoff from concrete, which is attributed to different physical and chemical compositions of the pavement types. Contaminant build-up and wash-off behaviours were modelled using exponential and saturation functions commonly applied in the US EPA's Stormwater Management Model (SWMM) showing good correlation between measured and modelled concentrations. Maximum build-up, half-saturation time, build-up rate constants and wash-off coefficients, necessary for stormwater contaminant modelling, were determined for the four contaminants studied. These parameters are required to model contaminant concentrations in urban runoff assisting in stormwater management decisions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Buildup of gamma ray photons in flyash concretes: A study

    International Nuclear Information System (INIS)

    Singh, Sukhpal; Ghumman, S.S.; Singh, Charanjeet; Thind, Kulwant Singh; Mudahar, Gurmel S.

    2010-01-01

    The gamma ray buildup factors of flyash concretes have been calculated by using Geometrical Progression formula in the energy region of 0.015-15 MeV as well as up to a penetration depth of 40 mean free paths, and have been studied as a function of incident photon energy. From the obtained results it is seen that for a fixed penetration depth the values of buildup factor are very large in the medium energy region and are small in the low and high energy regions. The results have been shown graphically.

  19. The effect of lateral decubitus position on nocturnal intraocular pressure over a habitual 24-hour period in healthy adults.

    Directory of Open Access Journals (Sweden)

    Jie Hao

    Full Text Available PURPOSE: To investigate the effect of lateral decubitus position (LDP on nocturnal intraocular pressure (IOP and the effect of LDP on 24-hour habitual IOP pattern in healthy subjects. METHODS: Intraocular pressure was measured every 2-hours using an Accupen Applanation Tonometer (Accutome, USA. During the diurnal period (7:30 am, 9:30 am, 11:30 am, 1:30 pm, 3:30 pm, 5:30 pm, 7:30 pm, and 9:30 pm, IOP was measured in the sitting position under bright light (500-1000 lux after the subjects had been seated for 5 min. The nocturnal IOP was measured in the supine position, right LDP, and left LDP, with randomized sequences, under dim light (<10 lux at 11:30 pm, 1:30 am, 3:30 am, and 5:30 am. The subjects were awakened and maintained each position for 5 min before the measurement. The 24-hour habitual IOP patterns were obtained according to the nocturnal position (supine, right LDP and left LDP for either eye. P<0.05 was considered to be significant. RESULTS: Nineteen healthy subjects were included with a mean age of 51.3±5.8 years. During the nocturnal period, a significant IOP difference was found between the dependent eye (the eye on the lower side of LDP and the supine position, but not for all the nocturnal time points. Over a 24-hour period, the effect of LDP on habitual IOP pattern was not statistically significant, although the mean nocturnal IOP and the diurnal-nocturnal IOP change for the right and the left eye in the LDP pattern was slightly higher than that in the sitting-supine pattern. CONCLUSION: Significant nocturnal IOP differences existed between the dependent eye and the supine, but did not occur consistently for all time points. Over a 24-hour period, the effect of LDP on habitual IOP pattern was not statistically significant in healthy subjects.

  20. Damage buildup and edge dislocation mobility in equiatomic multicomponent alloys

    Energy Technology Data Exchange (ETDEWEB)

    Granberg, F., E-mail: fredric.granberg@helsinki.fi [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Djurabekova, F. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Helsinki Institute of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Levo, E.; Nordlund, K. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland)

    2017-02-15

    Highlights: • We studied the damage buildup in equiatomic multicomponent alloys by MD simulations. • Edge dislocation mobility was lower in the studied alloys compared to elemental Ni. • Damage buildup in alloys saturated at lower levels than in elemental Ni. • Initial damage buildup is faster in alloys compared to elemental Ni. - Abstract: A new class of single phase metal alloys of equal atomic concentrations has shown very promising mechanical properties and good corrosion resistance. Moreover, a significant reduction in damage accumulation during prolonged irradiation has also been observed in these equiatomic multicomponent alloys. A comparison of elemental Ni with the two component NiFe- and the three component NiCoCr-alloy showed a substantial reduction in damage in both alloys, and an even larger difference was seen if only larger clusters were considered. One of the factors limiting the damage build-up in the alloys compared to the elemental material was seen to be dislocation mobility (Granberg et al., 2016). In this Article, we focus on a more thorough investigation of the mobility of edge dislocations in different cases of the Ni-, NiFe- and NiCoCr-samples. We find that even though the saturated amount of defects in the alloys is lower than in elemental Ni, the defect buildup in the early stages is faster in the alloys. We also find that the dislocation mobility in NiFe is lower than in Ni, at low stresses, and that the onset stress in NiFe is higher than in Ni. The same phenomenon was seen in comparison between NiFe and NiCoCr, since the three component alloy had lower dislocation mobility and higher onset stress. The dislocation velocity in elemental Ni plateaued out just under the forbidden velocity, whereas the alloys showed a more complex behaviour.

  1. Improved SVR Model for Multi-Layer Buildup Factor Calculation

    International Nuclear Information System (INIS)

    Trontl, K.; Pevec, D.; Smuc, T.

    2006-01-01

    The accuracy of point kernel method applied in gamma ray dose rate calculations in shielding design and radiation safety analysis is limited by the accuracy of buildup factors used in calculations. Although buildup factors for single-layer shields are well defined and understood, buildup factors for stratified shields represent a complex physical problem that is hard to express in mathematical terms. The traditional approach for expressing buildup factors of multi-layer shields is through semi-empirical formulas obtained by fitting the results of transport theory or Monte Carlo calculations. Such an approach requires an ad-hoc definition of the fitting function and often results with numerous and usually inadequately explained and defined correction factors added to the final empirical formula. Even more, finally obtained formulas are generally limited to a small number of predefined combinations of materials within relatively small range of gamma ray energies and shield thicknesses. Recently, a new approach has been suggested by the authors involving one of machine learning techniques called Support Vector Machines, i.e., Support Vector Regression (SVR). Preliminary investigations performed for double-layer shields revealed great potential of the method, but also pointed out some drawbacks of the developed model, mostly related to the selection of one of the parameters describing the problem (material atomic number), and the method in which the model was designed to evolve during the learning process. It is the aim of this paper to introduce a new parameter (single material buildup factor) that is to replace the existing material atomic number as an input parameter. The comparison of two models generated by different input parameters has been performed. The second goal is to improve the evolution process of learning, i.e., the experimental computational procedure that provides a framework for automated construction of complex regression models of predefined

  2. Electron-cloud build-up in hadron machines

    International Nuclear Information System (INIS)

    Furman, M.A.

    2004-01-01

    The first observations of electron-proton coupling effect for coasting beams and for long-bunch beams were made at the earliest proton storage rings at the Budker Institute of Nuclear Physics (BINP) in the mid-60's [1]. The effect was mainly a form of the two-stream instability. This phenomenon reappeared at the CERN ISR in the early 70's, where it was accompanied by an intense vacuum pressure rise. When the ISR was operated in bunched-beam mode while testing aluminum vacuum chambers, a resonant effect was observed in which the electron traversal time across the chamber was comparable to the bunch spacing [2]. This effect (''beam-induced multipacting''), being resonant in nature, is a dramatic manifestation of an electron cloud sharing the vacuum chamber with a positively-charged beam. An electron-cloud-induced instability has been observed since the mid-80's at the PSR (LANL) [3]; in this case, there is a strong transverse instability accompanied by fast beam losses when the beam current exceeds a certain threshold. The effect was observed for the first time for a positron beam in the early 90's at the Photon Factory (PF) at KEK, where the most prominent manifestation was a coupled-bunch instability that was absent when the machine was operated with an electron beam under otherwise identical conditions [4]. Since then, with the advent of ever more intense positron and hadron beams, and the development and deployment of specialized electron detectors [5-9], the effect has been observed directly or indirectly, and sometimes studied systematically, at most lepton and hadron machines when operated with sufficiently intense beams. The effect is expected in various forms and to various degrees in accelerators under design or construction. The electron-cloud effect (ECE) has been the subject of various meetings [10-15]. Two excellent reviews, covering the phenomenology, measurements, simulations and historical development, have been recently given by Frank Zimmermann [16

  3. Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans.

    Science.gov (United States)

    Silvani, Alessandro; Calandra-Buonaura, Giovanna; Johnson, Blair D; van Helmond, Noud; Barletta, Giorgio; Cecere, Anna G; Joyner, Michael J; Cortelli, Pietro

    2017-01-01

    The upright posture strengthens the coupling between heart period (HP) and systolic arterial pressure (SAP) consistently with a greater contribution of the arterial baroreflex to cardiac control, while paradoxically decreasing cardiac baroreflex sensitivity (cBRS). To investigate the physiological mechanisms that mediate the coupling between HP and SAP in response to different postures, we analyzed the cross-correlation functions between low-frequency HP and SAP fluctuations and estimated cBRS with the sequence technique in healthy male subjects during passive head-up tilt test (HUTT, n = 58), during supine wakefulness, supine slow-wave sleep (SWS), and in the seated and active standing positions ( n = 8), and during progressive loss of 1 L blood ( n = 8) to decrease central venous pressure in the supine position. HUTT, SWS, the seated, and the standing positions, but not blood loss, entailed significant increases in the positive correlation between HP and the previous SAP values, which is the expected result of arterial baroreflex control, compared with baseline recordings in the supine position during wakefulness. These increases were mirrored by increases in the low-frequency variability of SAP in each condition but SWS. cBRS decreased significantly during HUTT, in the seated and standing positions, and after blood loss compared with baseline during wakefulness. These decreases were mirrored by decreases in the RMSSD index, which reflects cardiac vagal modulation. These results support the view that the cBRS decrease associated with the upright posture is a byproduct of decreased cardiac vagal modulation, triggered by the arterial baroreflex in response to central hypovolemia. Conversely, the greater baroreflex contribution to cardiac control associated with upright posture may be explained, at least in part, by enhanced fluctuations of SAP, which elicit a more effective entrainment of HP fluctuations by the arterial baroreflex. These SAP fluctuations may result

  4. Hot ion buildup and lifetime in LITE. Final report

    International Nuclear Information System (INIS)

    1978-09-01

    An experimental investigation of hot ion buildup and lifetime in a small scale mirror device (LITE) is described. Hot ions were produced by 27 kV neutral beam injection into laser produced LiH plasmas and H plasmas produced by a washer gun. Hot H ion (12 kV) densities of approx. = 10 12 cm -3 were produced with the LiH target plasmas and densities an order of magnitude lower were produced with the washer gun target plasmas. Hot ion dominant plasmas were not achieved in LITE. The experimental measurements and subsequent analysis using numerical models of the plasma buildup indicate that in small, unshielded mirror plasmas, careful control must be maintained over the transient background gas density in the vicinity of the plasma surface. The hot ion lifetime in LITE was set by the transient cold neutral background resulting from the washer gun of reflux from the target plasma striking the adjacent surfaces

  5. Quality of USMC Officers: Buildup Vs. Reduction in Forces

    Science.gov (United States)

    2016-03-01

    the system and difficult to remove. Bacolod (2007), analyzes the decline in teacher quality due to expanded access to professional jobs for women ...display diminishing returns or contributions to an officer’s quality , productivity, job performance, or output. The FITREP is designed for the RS to take...minus FY Average of RS Highs between the Buildup and Drawdown An alternative measure of officer quality based on their job performance is the difference

  6. Humidity Buildup in Electronic Enclosures Exposed to Constant Conditions

    DEFF Research Database (Denmark)

    Conseil, Helene; Staliulionis, Zygimantas; Jellesen, Morten Stendahl

    2017-01-01

    Electronic components and devices are exposed to a wide variety of climatic conditions, therefore the protection of electronic devices from humidity is becoming a critical factor in the system design. The ingress of moisture into typical electronic enclosures has been studied with defined paramet....... The moisture buildup inside the enclosure has been simulated using an equivalent RC circuit consisting of variables like controlled resistors and capacitors to describe the diffusivity, permeability, and storage in polymers....

  7. BUILDUP OF PROACTIVE INTERFERENCE IN JAPANESE KANJI LEARNING

    OpenAIRE

    FUJITA, Tadashi

    1995-01-01

    The discriminative assumption on buildup of proactive interference in short-term memory predicts that when intertrial similarity of items is high, the proactive interference is built up while interlist similarity of items is low, the proactive interference is not built up. To test the discriminative assumption in Japanese Kanji learning, intertrial similarity was changed by the acoustic, the radical (as one of the figurative properties), and the radical plus semantic properties in Kanji. For ...

  8. Energy absorption and exposure build-up factors in teeth

    International Nuclear Information System (INIS)

    Manjunatha, H.C.; Rudraswamy, B.

    2010-01-01

    Full text: Gamma and X-radiation are widely used in medical imaging and radiation therapy. The user of radioisotopes must have knowledge about how radiation interacts with matter, especially with the human body, because when photons enter the medium/body, they degrade their energy and build up in the medium, giving rise to secondary radiation which can be estimated by a factor which is called the 'build-up factor'. It is essential to study the exposure build up factor in radiation dosimetry. G.P. fitting method has been used to compute energy absorption and exposure build-up factor of teeth (enamel outer surface (EOS), enamel middle (EM), enamel dentin junction towards enamel (EDJE), enamel dentin junction towards dentin (EDJD), dentin middle (DM) and dentin inner surface (DIS)) for wide energy range (0.015 MeV-15 MeV) up to the penetration depth of 40 mean free path. The dependence of energy absorption and exposure build up factor on incident photon energy, Penetration depth and effective atomic number has also been assessed. The relative dose distribution at a distance r from the point source is also estimated. The computed exposure and absorption build-up factors are useful to estimate the gamma and Bremsstrahlung radiation dose distribution teeth which is useful in clinical dosimetry

  9. The evaluation of nylon and polyethylene as build-up material in a neutron therapy beam

    International Nuclear Information System (INIS)

    Hough, J.H.; Binns, P.J.

    1995-01-01

    In high-energy neutron beams a substantial amount of build-up material is required to irradiate biological samples under conditions of charged particle equilibrium. Ideally A-150 tissue-equivalent plastic is used for this purpose. This material is however not always readily available and hence the need for a substitute compound. The selected hydrocarbon should satisfy two requirements: the quality of the radiation on the distal side needs to be the same as that measured for A-150 plastic and the absorbed dose should remain consistent. A tissue-equivalent proportional counter operating at reduced pressure not only measures the absorbed dose accurately but provides a means for assessing the nature of a radiation field in terms of a secondary charged particle spectrum. Using build-up caps manufactured from nylon (type 6) and polyethylene, it is shown that the former is an acceptable substitute for A-150 plastic. The data further demonstrate that both the absorbed dose and the spectral character of the measured single-event distribution are altered when polyethylene is used and that these discrepancies are attributable to the higher hydrogen content of polyethylene. (Author)

  10. Activities concerning a re-evaluation of gamma-ray buildup factors in Japan

    International Nuclear Information System (INIS)

    Hirayama, Hideo

    2000-01-01

    Research related to gamma-ray buildup factors in Japan are continuing to improve in accuracy and usefulness after the publication of new standard buildup factors as NUREG/CR-5740. Buildup factors for homogeneous materials were studied by three different calculation methods. Several improvements were made to calculate buildup factors up to 40 mfp for various materials for a wide energy range at each code. Systematic data production of buildup factors for multilayer materials were performed by using the EGS4 Monte Carlo code, and were used to improve the fitting formula. These research activities related to gamma-ray buildup factors performed in Japan are presented together with discussions concerning re-evaluation of buildup factors. (author)

  11. Efforts to control radiation build-up in Ringhals

    Energy Technology Data Exchange (ETDEWEB)

    Egner, K.; Aronsson, P.O.; Erixon, O. [Vattenfall AB, Vaeroebacka (Sweden)

    1995-03-01

    It is well known that good control of the primary chemistry in a PWR is essential in order to minimize material problems and fuel damages. It has also been well established that the water chemistry has a great influence on accumulation of corrosion products on the fuel and the radiation build-up on primary system surfaces. Ringhals was one of the pioneers to increase operating pH in order to reduce radiation build-up and has now been operating for ten years with pH at 7.4 or (in later years) 7.2. Our experience is favourable and includes low radiation levels in the new (1989) steam generators of Ringhals 2. Ringhals 4 has operated almost its whole life at pH 7.2 or higher and it remains one of the cleanest PWRs of its vintage. In addition to strict adherence to a stable operating chemistry, Ringhals is now working on a program with the aim to find optimum shut-down and start-up chemistry to reduce activity levels in the primary systems. A particular goal is to use the shut-down and start-up chemistry at the 1994 outage in Ringhals 3 in order to reduce doserates in preparation for the planned steam generator replacement in 1995. The paper summarizes the experience to date of the established operating chemistry, on-going tests with modified shut-down and start-up chemistry and other measures to limit or reduce the activity build-up.

  12. Efforts to control radiation build-up in Ringhals

    International Nuclear Information System (INIS)

    Egner, K.; Aronsson, P.O.; Erixon, O.

    1995-01-01

    It is well known that good control of the primary chemistry in a PWR is essential in order to minimize material problems and fuel damages. It has also been well established that the water chemistry has a great influence on accumulation of corrosion products on the fuel and the radiation build-up on primary system surfaces. Ringhals was one of the pioneers to increase operating pH in order to reduce radiation build-up and has now been operating for ten years with pH at 7.4 or (in later years) 7.2. Our experience is favourable and includes low radiation levels in the new (1989) steam generators of Ringhals 2. Ringhals 4 has operated almost its whole life at pH 7.2 or higher and it remains one of the cleanest PWRs of its vintage. In addition to strict adherence to a stable operating chemistry, Ringhals is now working on a program with the aim to find optimum shut-down and start-up chemistry to reduce activity levels in the primary systems. A particular goal is to use the shut-down and start-up chemistry at the 1994 outage in Ringhals 3 in order to reduce doserates in preparation for the planned steam generator replacement in 1995. The paper summarizes the experience to date of the established operating chemistry, on-going tests with modified shut-down and start-up chemistry and other measures to limit or reduce the activity build-up

  13. PyECLOUD and build-up simulations at CERN

    International Nuclear Information System (INIS)

    Iadarola, G; Rumolo, G

    2013-01-01

    PyECLOUD is a newly developed code for the simulation of the electron cloud (EC) build-up in particle accelerators. Almost entirely written in Python, it is mostly based on the physical models already used in the ECLOUD code but, thanks to the implementation of new optimized algorithms, it exhibits a significantly improved performance in accuracy, speed, reliability and flexibility. Such new features of PyECLOUD have been already broadly exploited to study EC observations in the Large Hadron Collider (LHC) and its injector chain as well as for the extrapolation to high luminosity upgrade scenarios. (author)

  14. Buildup of 236U in the gaseous diffusion plant product

    International Nuclear Information System (INIS)

    Ford, J.S.

    1975-01-01

    A generalized projection of the average annual 236 U concentration that can be expected in future enriched uranium product from the US-ERDA gaseous diffusion plants when reprocessed fuels become available for cascade feeding is given. It is concluded that the buildup of 236 U is not an ever-increasing function, but approaches a limiting value. Projected concentrations result in only slight separative work losses and present no operational problem to ERDA in supplying light water reactor requirements. The use of recycle uranium from power reactor spent fuels will result in significant savings in natural uranium feed

  15. A new approach to age-period-cohort analysis using partial least squares regression: the trend in blood pressure in the Glasgow Alumni cohort.

    Directory of Open Access Journals (Sweden)

    Yu-Kang Tu

    2011-04-01

    Full Text Available Due to a problem of identification, how to estimate the distinct effects of age, time period and cohort has been a controversial issue in the analysis of trends in health outcomes in epidemiology. In this study, we propose a novel approach, partial least squares (PLS analysis, to separate the effects of age, period, and cohort. Our example for illustration is taken from the Glasgow Alumni cohort. A total of 15,322 students (11,755 men and 3,567 women received medical screening at the Glasgow University between 1948 and 1968. The aim is to investigate the secular trends in blood pressure over 1925 and 1950 while taking into account the year of examination and age at examination. We excluded students born before 1925 or aged over 25 years at examination and those with missing values in confounders from the analyses, resulting in 12,546 and 12,516 students for analysis of systolic and diastolic blood pressure, respectively. PLS analysis shows that both systolic and diastolic blood pressure increased with students' age, and students born later had on average lower blood pressure (SBP: -0.17 mmHg/per year [95% confidence intervals: -0.19 to -0.15] for men and -0.25 [-0.28 to -0.22] for women; DBP: -0.14 [-0.15 to -0.13] for men; -0.09 [-0.11 to -0.07] for women. PLS also shows a decreasing trend in blood pressure over the examination period. As identification is not a problem for PLS, it provides a flexible modelling strategy for age-period-cohort analysis. More emphasis is then required to clarify the substantive and conceptual issues surrounding the definitions and interpretations of age, period and cohort effects.

  16. Energy buildup in sheared force-free magnetic fields

    Science.gov (United States)

    Wolfson, Richard; Low, Boon C.

    1992-01-01

    Photospheric displacement of the footpoints of solar magnetic field lines results in shearing and twisting of the field, and consequently in the buildup of electric currents and magnetic free energy in the corona. The sudden release of this free energy may be the origin of eruptive events like coronal mass ejections, prominence eruptions, and flares. An important question is whether such an energy release may be accompanied by the opening of magnetic field lines that were previously closed, for such open field lines can provide a route for matter frozen into the field to escape the sun altogether. This paper presents the results of numerical calculations showing that opening of the magnetic field is permitted energetically, in that it is possible to build up more free energy in a sheared, closed, force-free magnetic field than is in a related magnetic configuration having both closed and open field lines. Whether or not the closed force-free field attains enough energy to become partially open depends on the form of the shear profile; the results presented compare the energy buildup for different shear profiles. Implications for solar activity are discussed briefly.

  17. New buildup factor data for point kernel calculations

    International Nuclear Information System (INIS)

    Trubey, D.K.; Harima, Y.

    1986-01-01

    An American Nuclear Society Standards Committee Working Group, identified as ANS-6.4.3, is developing a set of evaluated gamma-ray isotropic point-source buildup factors and attenuation coefficients for a standard reference data base. As a first step, a largely unpublished set of buildup factors calculated with the moments method has been evaluated by recalculating key values with Monte Carlo, integral transport, and discrete ordinates methods. Attention is being given to frequently-neglected processes such as bremsstrahlung and the effect of introducing a tissue phantom behind the shield. The proposed standard contains data for a source energy range from 15 keV to 15 MeV and for approximately 19 elements and 3 mixtures (water, air, and concrete). The data will also be represented as coefficients for the G-P fitting function. The 1985 data base was released as part of the CCC-493B/QAD-CGGP code package available from the Radiation Shielding Information Center (RSIC)

  18. Scintiscanning of arthritis and analysis of build-up curves

    International Nuclear Information System (INIS)

    Yamagishi, Tsuneo; Omori, Shigeo; Miyawaki, Haruo; Maniwa, Masato; Yoshizaki, Kenichi

    1975-01-01

    In the present study 40 knee joints with rheumatoid arthritis, 23 knee joints with osteoarthrosis deformans, 3 knee joints with non-synovitis, one knee joint with pyogenic arthritis and 4 normal knee joints were scanned. By analysis of build-up curves obtained immediately after the intravenous injection of sup(99m)Tc-pertechnetate, the rate of accumulation of radioactivity (t 1/2) in the affected joints was simultaneously estimated in order to compare them with clinical findings. 1. Scintiscanning of arthritis, rheumatoid arthritis, osteoarthrosis deformans of the knee joint, non-specific synovitis, and pyogenic arthritis of the knee joint, yielded a positive scan for all of the joint diseases. 2. In the scintigram of healthy knee joints, there are no areas of RI accumulation or right to left difference. 3. In some instances abnormal uptake of RI was seen on scintigrams of arthritis even after normal clinical and laboratory findings had been achieved with therapy. 4. sup(99m)Tc-pertechnetate, a radionuclide with a short half-life, allows repeated scans and provides a useful radiologic means of evaluating therapeutic course and effectiveness. 5. Analysis of build-up curves revealed that the rate of accumulation of RI was faster in rheumatoid arthritis than in osteoarthrosis deformans. (auth.)

  19. Zinc injection helps reduce radiation field buildup in BWRs

    International Nuclear Information System (INIS)

    Wood, C.

    1991-01-01

    The injection of zinc into the reactor water of BWRs (Boiling Water Reactors) was a technique developed by General Electric (GE) and the Electric Power Research Institute (EPRI) to control the buildup of radiation fields from cobalt-60 on out-of-core piping. The presence of 5-10ppb zinc in the reactor water reduces the growth of oxide films on stainless steel surfaces, thereby reducing the number of sites available for the incorporation of cobalt; zinc also competes with cobalt for the sites. In September 1990, EPRI organized a workshop at the request of several US utilities to provide a forum to discuss experiences with zinc injection. The meeting focused on six main issues: the effect of zinc on radiation fields in normal water chemistry; the radiation buildup in hydrogen water chemistry, with and without zinc; the effects of zinc-65; the corrosion of fuel cladding and structural materials; the performance of zinc injection and monitoring equipment; and planning for zinc injection. (author)

  20. Higher pressure periodic CO/sub 2/ laser with non-self-sustaining discharge and UV ionization

    Energy Technology Data Exchange (ETDEWEB)

    Muratov, E A; Pismennyi, V D; Rakhimov, A T

    1979-02-01

    Stimulated emission was achieved in a CO/sub 2/ laser operating at 250 torr excited by a periodic non-self-sustaining discharge controlled by a spark source of UV radiation. Use of a UV source operating in periodic pulse regime is shown to permit quasicontinuous operation of the laser with characteristic radiating times up to several hundred microseconds.

  1. Two-Dimensional Simulation of Spatial-Temporal Behaviors About Period Doubling Bifurcation in an Atmospheric-Pressure Dielectric Barrier Discharge

    International Nuclear Information System (INIS)

    Zhang Jiao; Wang Yanhui; Wang Dezhen; Zhuang Juan

    2014-01-01

    As a spatially extended dissipated system, atmospheric-pressure dielectric barrier discharges (DBDs) could in principle possess complex nonlinear behaviors. In order to improve the stability and uniformity of atmospheric-pressure dielectric barrier discharges, studies on temporal behaviors and radial structure of discharges with strong nonlinear behaviors under different controlling parameters are much desirable. In this paper, a two-dimensional fluid model is developed to simulate the radial discharge structure of period-doubling bifurcation, chaos, and inverse period-doubling bifurcation in an atmospheric-pressure DBD. The results show that the period-2n (n = 1, 2…) and chaotic discharges exhibit nonuniform discharge structure. In period-2n or chaos, not only the shape of current pulses doesn't remains exactly the same from one cycle to another, but also the radial structures, such as discharge spatial evolution process and the strongest breakdown region, are different in each neighboring discharge event. Current-voltage characteristics of the discharge system are studied for further understanding of the radial structure. (low temperature plasma)

  2. Characterizing polycyclic aromatic hydrocarbon build-up processes on urban road surfaces

    International Nuclear Information System (INIS)

    Liu, Liang; Liu, An; Li, Dunzhu; Zhang, Lixun; Guan, Yuntao

    2016-01-01

    Reliable prediction models are essential for modeling pollutant build-up processes on urban road surfaces. Based on successive samplings of road deposited sediments (RDS), this study presents empirical models for mathematical replication of the polycyclic aromatic hydrocarbon (PAH) build-up processes on urban road surfaces. The contaminant build-up behavior was modeled using saturation functions, which are commonly applied in US EPA's Stormwater Management Model (SWMM). Accurate fitting results were achieved in three typical urban land use types, and the applicability of the models was confirmed based on their acceptable relative prediction errors. The fitting results showed high variability in PAH saturation value and build-up rate among different land use types. Results of multivariate data and temporal-based analyses suggested that the quantity and property of RDS significantly influenced PAH build-up. Furthermore, pollution sources, traffic parameters, road surface conditions, and sweeping frequency could synthetically impact the RDS build-up and RDS property change processes. Thus, changes in these parameters could be the main reason for variations in PAH build-up in different urban land use types. - Highlights: • Sufficient robust prediction models were established for analysis of PAH build-up on urban road surfaces. • PAH build-up processes showed high variability among different land use types. • Pollution sources as well as the quantity and property of RDS mainly influenced PAH build-up. - Sufficient robust prediction models were established for analysis of PAH build-up on urban road surfaces. Pollution sources as well as the quantity and property of RDS mainly influenced PAH build-up.

  3. Buildup factor studies of HCO-materials as a function of weight fraction of constituent elements

    International Nuclear Information System (INIS)

    Brar, G.S.; Sidhu, G.S.; Singh, Parjit S.; Mudahar, Gurmel S.

    1999-01-01

    The effects of fractional abundance of constituent elements have been investigated on the energy absorption buildup factors of HCO-materials for some incident photon energies at a fixed penetration depth of 20 mfp. At low incident photon energies, a change in buildup factor is seen whereas buildup factor values of HCO-materials are independent of fractional abundances of H, C and O for high energies

  4. New concept of the buildup factor in bent ducts

    International Nuclear Information System (INIS)

    Faik Ouahab, Z.; Jehouani, A.; Groetz, J.-E.

    2011-01-01

    A major problem confronting the radiation shielding designer is the accurate determination of neutron streaming through various penetrations in walls, ducts and mazes. The previous studies on neutron transmission were performed through empty ducts. The aim of this work is to evaluate the neutron transmission probability through a filled bent duct and the proposition of a new concept of the buildup factor for neutrons in multilegged ducts. An angular biaising technique is used in the Monte Carlo simulations to accelerate the calculation convergence. Results are first compared with those obtained by the MCNPX code. For an empty bent duct, the neutron transmission is only due to the neutron reflection on the duct wall. For a filled duct, the major contribution is due to the scattering on the atoms filling the duct.

  5. Detection of hydrogen buildup in initially pure nonhydrogenous liquids

    International Nuclear Information System (INIS)

    McNeany, S.R.; Jenkins, J.D.

    1978-12-01

    A technique for monitoring hydrogen buildup in initially pure nonhydrogenous liquids is described in this report. The detection method is based upon the neutron-moderating properties of hydrogen. The analysis leading to the selection and design of a hydrogen-monitoring device is described. An experimental mockup of the device was then constructed and tested for hydrogen sensitivity. A hot cell was used for these tests. A device proved capable of measuring hydrogen concentrations in the range of 0 to 13.0 x 10 27 atoms/m 3 , with an accuracy of about 1.0 x 10 27 atoms/m 3 . A typical measurement can be made in 3 to 5 min. The experimental results confirmed the sensitivities predicted by the analysis and demonstrated that such a device would be practical for hydrogen concentration measurements for criticality control in an HTGR fuel refabrication plant

  6. Electron-Cloud Build-Up: Theory and Data

    International Nuclear Information System (INIS)

    Furman, M.A.

    2010-01-01

    We present a broad-brush survey of the phenomenology, history and importance of the electron-cloud effect (ECE). We briefly discuss the simulation techniques used to quantify the electron-cloud (EC) dynamics. Finally, we present in more detail an effective theory to describe the EC density build-up in terms of a few effective parameters. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire 'ECLOUD' series. In addition, the proceedings of the various flavors of Particle Accelerator Conferences contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC.

  7. Investigating the build-up of precedence effect using reflection masking

    DEFF Research Database (Denmark)

    Hartcher-O'Brien, Jessica; Buchholz, Jörg

    2006-01-01

    signal processing, such an approach represents a bottom-up approach to the buildup of precedence. Three conditioner configurations measuring a possible buildup of reflection suppression were compared to the baseline RMT for four reflection delays ranging from 2.5–15 ms. No buildup of reflection...... suppression was observed for any of the conditioner configurations. Buildup of template (decrease in RMT for two of the conditioners), on the other hand, was found to be delay dependent. For five of six listeners, with reflection delay=2.5 and 15 ms, RMT decreased relative to the baseline. For 5- and 10-ms...

  8. Damage buildup and edge dislocation mobility in equiatomic multicomponent alloys

    Science.gov (United States)

    Granberg, F.; Djurabekova, F.; Levo, E.; Nordlund, K.

    2017-02-01

    A new class of single phase metal alloys of equal atomic concentrations has shown very promising mechanical properties and good corrosion resistance. Moreover, a significant reduction in damage accumulation during prolonged irradiation has also been observed in these equiatomic multicomponent alloys. A comparison of elemental Ni with the two component NiFe- and the three component NiCoCr-alloy showed a substantial reduction in damage in both alloys, and an even larger difference was seen if only larger clusters were considered. One of the factors limiting the damage build-up in the alloys compared to the elemental material was seen to be dislocation mobility (Granberg et al., 2016). In this Article, we focus on a more thorough investigation of the mobility of edge dislocations in different cases of the Ni-, NiFe- and NiCoCr-samples. We find that even though the saturated amount of defects in the alloys is lower than in elemental Ni, the defect buildup in the early stages is faster in the alloys. We also find that the dislocation mobility in NiFe is lower than in Ni, at low stresses, and that the onset stress in NiFe is higher than in Ni. The same phenomenon was seen in comparison between NiFe and NiCoCr, since the three component alloy had lower dislocation mobility and higher onset stress. The dislocation velocity in elemental Ni plateaued out just under the forbidden velocity, whereas the alloys showed a more complex behaviour.

  9. Periodic motions and chaos for a damped mobile piston system in a high pressure gas cylinder with P control

    International Nuclear Information System (INIS)

    Wang, Donghua; Huang, Jianzhe

    2017-01-01

    In this paper, the complex motions for a moving piston in a closed gas cylinder will be analyzed using the discrete implicit maps method. The strong nonlinearity of such system will be observed due to the large quadratic and cubic stiffness. Period-1 motions which contain high order of harmonic components will be presented. The periodic motions will be discretized into multiple continuous mappings, and such mapping can be analyzed via Newton–Raphson iteration. The stability analysis will be given and the analytic conditions for the saddle-node and period-doubling bifurcation will be determined. From the semi-analytic solution route, the possible motions without considering the impact of the piston with the end wall of the cylinder will be obtained analytically. The scheme to reduce the vibration of the piston can be obtained through the parameter studies.

  10. Experimental investigations in high-pressure natural circulation loop: progress report for the period January-June, 1999

    International Nuclear Information System (INIS)

    Naveen Kumar; Rajalakshmi, R.; Kulkarni, R.D.; Sagar, T.V.; Vijayan, P.K.; Saha, D.

    2000-02-01

    The Advanced Heavy Water Reactor employs natural circulation as the normal mode of coolant circulation. This is expected to enhance safety and reliability as it eliminates all safety issues associated with the pump failure. Two-phase natural circulation, however, is susceptible to several types of instabilities. In addition, the flow rate in a natural circulation loop is a dependent quantity and is not known a priori. Reliable calculations of the flow rate and stability behaviour are essential to ensure the success of AHWR design. Hence computer codes developed to predict the steady state flow rate and stability behaviour require validation against test data under natural circulation. For this purpose a high-pressure natural circulation loop has been designed, constructed and commissioned. Steady state experiments have been carried out in this loop to study the effect of pressure on natural circulation flow rate. The experimental results for this case are presented in this report. More experiments are planned in future to study the various aspects of two-phase natural circulation. (author)

  11. SU-E-T-184: Feasibility of Superabsorbent Polymers as a Buildup Material

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, T; Sheu, R; Lo, Y [Mount Sinai Medical Center, NY, NY (United States)

    2014-06-01

    Purpose: To investigate the feasibility of superabsorbent polymers as a buildup material for radiation therapy Methods: A standard bolus, a layered damp towel, and a superabsorbent polymer (SAP) phantom were created and scanned to compare the Hounsfield units of each buildup material. A single field plan was developed on Eclipse TPS with AAA dose calculation algorithm to examine dose buildup. Relative film dosimetery (EBT3) was performed to evaluate the surface dose with each buildup material. Each buildup material had an approximate thickness of 0.5 cm and 100 monitor units with 6MV were delivered with solid water placed underneath film to simulate backscatter and more realistic surface dose. Results: The average HU units of the bolus, wet towel, and SAP phantom were 75 (SD=3), -378 (SD=113), -198 (SD=45) respectively. AAA dose calculation demonstrated sufficient dose buildup in all three materials. The relative surfaces doses to film were 23.7% without buildup, 87.5% with 0.5 cm bolus, 92.4% for the SAP phantom, and 87.1% for the damp towel. Conclusion: We demonstrate that superabsorbent polymers can provide sufficient dose buildup. Furthermore, due to the form in which SAPs are traditionally manufactured, this material is less expensive conforms more easily to irregular surfaces than standard sheets of bolus. Also, as a substance which is designed to absorb and retain water efficiently, SAPs are much more comfortable and more consistent than damp towels.

  12. SU-E-T-184: Feasibility of Superabsorbent Polymers as a Buildup Material

    International Nuclear Information System (INIS)

    Tseng, T; Sheu, R; Lo, Y

    2014-01-01

    Purpose: To investigate the feasibility of superabsorbent polymers as a buildup material for radiation therapy Methods: A standard bolus, a layered damp towel, and a superabsorbent polymer (SAP) phantom were created and scanned to compare the Hounsfield units of each buildup material. A single field plan was developed on Eclipse TPS with AAA dose calculation algorithm to examine dose buildup. Relative film dosimetery (EBT3) was performed to evaluate the surface dose with each buildup material. Each buildup material had an approximate thickness of 0.5 cm and 100 monitor units with 6MV were delivered with solid water placed underneath film to simulate backscatter and more realistic surface dose. Results: The average HU units of the bolus, wet towel, and SAP phantom were 75 (SD=3), -378 (SD=113), -198 (SD=45) respectively. AAA dose calculation demonstrated sufficient dose buildup in all three materials. The relative surfaces doses to film were 23.7% without buildup, 87.5% with 0.5 cm bolus, 92.4% for the SAP phantom, and 87.1% for the damp towel. Conclusion: We demonstrate that superabsorbent polymers can provide sufficient dose buildup. Furthermore, due to the form in which SAPs are traditionally manufactured, this material is less expensive conforms more easily to irregular surfaces than standard sheets of bolus. Also, as a substance which is designed to absorb and retain water efficiently, SAPs are much more comfortable and more consistent than damp towels

  13. Variability of blood pressure and blood glucose during perioperative period for patients with secondary neovascular glaucoma after silicone oil removed in PDR

    Directory of Open Access Journals (Sweden)

    Fu-Lin Gao

    2015-06-01

    Full Text Available AIM:To research blood pressure and blood glucose variability during peroperative period for patients with secondary neovasular glaucoma(NVGafter silicone oil removed in proliferative diabetic retinaopathy(PDR.METHODS: Totally, 271 patients(271 eyesundergone surgery of vitrectomy and silicon-oil tamponade combined with cataract were respective analyzed. Fourteen patients(14 eyeswith secondary NVG after silicon oil removed and randomly controlled group of no NVG according with ages, operation method in the same time were studied. The blood pressure and blood glucose variability during peroperative period was analyzed, and did comparison after excluded contralateral eye. The complications of 271 patients were surveyed in following-up period 1~12mo. The incidence of NVG, the time, blood pressure, blood glucose and glycated hemoglobin(Hbc%variability during peroperative period was statisticed and compared by software of SPSS 11.0.RESULTS: Fourteen eyes(5.2%of 271 cases was with secondary NVG(female: 4 eyes, 28.6%; male: 10 eyes, 71.4%, average ages was 57.07 years(49~68 years. NVG presented in the 107~ 135d after vitrectomy and 7~45d(average 31.78dafter silicon-oil removed. Diabetes mellitus was 10~15(average 13.2a. In NVG group, the variability of blood glucose was 4.0~10.2mmol/L(mean 8.52±3.24mmol/L, variable coefficient was 0.48. In NNVG group, the variability of blood glucose was 5.0~8.2mmol/L(mean 7.22±0.24mmol/L, variable coefficient was 0.43. It was significantly difference in comparison in variable coefficient(PPPPCONCLUSION: There are significant variability on fasting blood glucose, daytime SBP and night DBP during perioperative in PDR patients with secondary NVG. It might be occurred 1wk after silicone oil removal surgery.

  14. Recommendations on dose buildup factors used in models for calculating gamma doses for a plume

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.; Thykier-Nielsen, S.

    1980-09-01

    Calculations of external γ-doses from radioactivity released to the atmosphere have been made using different dose buildup factor formulas. Some of the dose buildup factor formulas are used by the Nordic countries in their respective γ-dose models. A comparison of calculated γ-doses using these dose buildup factors shows that the γ-doses can be significantly dependent on the buildup factor formula used in the calculation. Increasing differences occur for increasing plume height, crosswind distance, and atmospheric stability and also for decreasing downwind distance. It is concluded that the most accurate γ-dose can be calculated by use of Capo's polynomial buildup factor formula. Capo-coefficients have been calculated and shown in this report for γ-energies below the original lower limit given by Capo. (author)

  15. Radiation buildup and control in BWR recirculation piping

    International Nuclear Information System (INIS)

    Meyer, W.; Wood, R.M.; Rao, T.V.; Vook, R.W.

    1987-01-01

    Boiling water nuclear reactors (BWRs) employ stainless steel (Types 304 or 316 NG) pipes in which high-purity water at temperatures of ∼ 275 0 C are circulated. Various components of the system, such as valves and bearings, often contain hard facing metal alloys such as Stellite-6. These components, along with the stainless steel tubing and feedwater, serve as sources of 59 Co. This cobalt, along with other soluble and insoluble impurities, is carried along with the circulating water to the reactor core where it is converted to radioactive 60 Co. After reentering the circulating water, the 60 Co can be incorporated into a complex corrosion layer in the form of CoCr 2 O 4 and/or CoFe 2 O 4 . The presence of even small amounts of 60 Co on the walls of BWR cooling systems is the dominant contributor to inplant radiation levels. Thus BWR owners and their agents are expending significant time and resources in efforts to reduce both the rate and amount of 60 Co buildup. The object of this research is twofold: (a) to form a thin diffusion barrier against the outward migration of cobalt from a cobalt-containing surface and (b) to prevent the growth of a 60 Co-containing corrosion film. The latter goal was the more important since most of the radioactive cobalt will originate from sources other than the stainless steel piping itself

  16. The Mechanism for Energy Buildup in the Solar Corona

    Science.gov (United States)

    Antiochos, Spiro; Knizhnik, Kalman; DeVore, Richard

    2017-10-01

    Magnetic reconnection and helicity conservation are two of the most important basic processes determining the structure and dynamics of laboratory and space plasmas. The most energetic dynamics in the solar system are the giant CMEs/flares that produce the most dangerous space weather at Earth, yet may also have been essential for the origin of life. The origin of these explosions is that the lowest-lying magnetic flux in the Sun's corona undergoes the continual buildup of stress and free energy that can be released only through explosive ejection. We perform MHD simulations of a coronal volume driven by quasi-random boundary flows designed to model the processes by which the solar interior drives the corona. Our simulations are uniquely accurate in preserving magnetic helicity. We show that even though small-scale stress is injected randomly throughout the corona, the net result of magnetic reconnection is a coherent stressing of the lowest-lying field lines. This highly counter-intuitive result - magnetic stress builds up locally rather than spreading out to a minimum energy state - is the fundamental mechanism responsible for the Sun's magnetic explosions. It is likely to be a mechanism that is ubiquitous throughout laboratory and space plasmas. This work was supported by the NASA LWS and SR Programs.

  17. Optimum Water Chemistry in radiation field buildup control

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chien, C. [Vallecitos Nuclear Center, Pleasanton, CA (United States)

    1995-03-01

    Nuclear utilities continue to face the challenGE of reducing exposure of plant maintenance personnel. GE Nuclear Energy has developed the concept of Optimum Water Chemistry (OWC) to reduce the radiation field buildup and minimize the radioactive waste production. It is believed that reduction of radioactive sources and improvement of the water chemistry quality should significantly reduce both the radiation exposure and radwaste production. The most important source of radioactivity is cobalt and replacement of cobalt containing alloy in the core region as well as in the entire primary system is considered the first priority to achieve the goal of low exposure and minimized waste production. A plant specific computerized cobalt transport model has been developed to evaluate various options in a BWR system under specific conditions. Reduction of iron input and maintaining low ionic impurities in the coolant have been identified as two major tasks for operators. Addition of depleted zinc is a proven technique to reduce Co-60 in reactor water and on out-of-core piping surfaces. The effect of HWC on Co-60 transport in the primary system will also be discussed.

  18. Blood pressure changes associated with sibutramine and weight management - an analysis from the 6-week lead-in period of the sibutramine cardiovascular outcomes trial (SCOUT)

    DEFF Research Database (Denmark)

    Sharma, A M; Caterson, I D; Coutinho, W

    2009-01-01

    OBJECTIVE: To explore vital sign changes among patient subgroups during the 6-week lead-in period of the sibutramine cardiovascular outcomes (SCOUT) trial. METHODS: SCOUT is an ongoing, double-blind, randomized, placebo-controlled outcome trial in overweight/obese patients at high risk of a cardi......OBJECTIVE: To explore vital sign changes among patient subgroups during the 6-week lead-in period of the sibutramine cardiovascular outcomes (SCOUT) trial. METHODS: SCOUT is an ongoing, double-blind, randomized, placebo-controlled outcome trial in overweight/obese patients at high risk...... of a cardiovascular event. During the 6-week lead-in period, 10,742 patients received sibutramine and weight management. Vital sign changes were assessed post hoc by initial blood pressure (mmHg) categorized as normal (or=140/>or=90); weight change...... categories (weight gain/no weight change, >0 to 2.5% weight loss, >2.5 to 5% weight loss and >5% weight loss) and current antihypertensive medication class use (none, one, or two or more). To assess the impact of sibutramine on blood pressure and pulse rate, only patients (N = 10,025) who reported no change...

  19. Process for start-up and slack period operation of fully charged boilers, e. g. of coal pressure gasification plants, and boiler system to carry out the process

    Energy Technology Data Exchange (ETDEWEB)

    Meyer-Kahrweg, H

    1978-10-19

    For the start-up and slack period of fully charged boilers hot water of e.g. 180/sup 0/C from a high pressure heater which is fed by a start-up boiler is used. In the first instance the boiler, its preheater and the vaporizer are filled with hot water from the start-up boiler until a medium water level is obtained. Subsequently water from the water separator is recycled through the preheater and the boiler by forced circulation and it is heated up to the hot water temperature by the start-up boiler. After the desired temperature has been reached the pressure combustion is ignited and the circulation through the preheater is interrupted by reversing to direct feed back. A considerable shortening of the start-up time is achieved because no heat is released to the condensation water in the boiler system as is done usually.

  20. Effect of Reynolds Number and Periodic Unsteady Wake Flow Condition on Boundary Layer Development, Separation, and Intermittency Behavior Along the Suction Surface of a Low Pressure Turbine Blade

    Science.gov (United States)

    Schobeiri, M. T.; Ozturk, B.; Ashpis, David E.

    2007-01-01

    The paper experimentally studies the effects of periodic unsteady wake flow and different Reynolds numbers on boundary layer development, separation and re-attachment along the suction surface of a low pressure turbine blade. The experimental investigations were performed on a large scale, subsonic unsteady turbine cascade research facility at Turbomachinery Performance and Flow Research Laboratory (TPFL) of Texas A&M University. The experiments were carried out at Reynolds numbers of 110,000 and 150,000 (based on suction surface length and exit velocity). One steady and two different unsteady inlet flow conditions with the corresponding passing frequencies, wake velocities, and turbulence intensities were investigated. The reduced frequencies chosen cover the operating range of LP turbines. In addition to the unsteady boundary layer measurements, surface pressure measurements were performed. The inception, onset, and the extent of the separation bubble information collected from the pressure measurements were compared with the hot wire measurements. The results presented in ensemble-averaged, and the contour plot forms help to understand the physics of the separation phenomenon under periodic unsteady wake flow and different Reynolds number. It was found that the suction surface displayed a strong separation bubble for these three different reduced frequencies. For each condition, the locations defining the separation bubble were determined carefully analyzing and examining the pressure and mean velocity profile data. The location of the boundary layer separation was dependent of the Reynolds number. It is observed that starting point of the separation bubble and the re-attachment point move further downstream by increasing Reynolds number from 110,000 to 150,000. Also, the size of the separation bubble is smaller when compared to that for Re=110,000.

  1. Response to long-period seismic waves recorded by broadband seismometer and pore pressure sensor at IODP Site C0002, Nankai Trough

    Science.gov (United States)

    Kitada, K.; Araki, E.; Kimura, T.; Saffer, D. M.

    2013-12-01

    Long term in situ monitoring of seismic activity, slow slip event, and pore fluid behavior around mega earthquake zone is important for understanding the processes of earthquake generation and strain accumulation. In order to characterize the response to long-period seismic waves, we compared waveforms and hydroseismograms recorded by broadband seismometer and pore pressure transducers, respectively, which were installed at IODP Site C0002 in the Nankai Trough Kumano Basin. The borehole monitoring system sensor array at Site C0002 is designed to collect multiparameter observations covering a dynamic range of events, including local microearthquakes, low frequency earthquakes, and large-scale earthquakes similar to the Tonankai earthquake. The suite of sensors for the downhole portion of the observatory includes a broadband seismometer (CMG3TBD, Guralp Systems Ltd.) with sampling rate of 100Hz at the depth of 907mbsf, and four pressure ports connected to pressure gauges located at 948mbsf, 917mbsf, 766mbsf, and at the seafloor. The sampling rate of the data logger was set to 1Hz after successful connection to the DONET seafloor cable network for real-time monitoring on 24 Jan 2013. Since then, we processed 12 earthquakes between a moment magnitude of 6.5 to 8.3. In addition to the comparison of long-period surface waves waveform and pressure data, we compared the records with theoretical strain seismograms. The latter were calculated by normal mode summation using the earth model PREM of Dziewonski and Anderson (1981). A Butterworth bandpass filter was applied to the records with cut-off frequencies of 0.003 and 0.1 Hz. Our initial results indicate that the hydroseismograms correspond well with the vertical rather than the horizontal (radial and transverse) components in seismic data. The observed hydroseismogram have a good correlation with the predicted volumetric strain seismogram, especially for the Okhotsk (2013/05/24 14:17UT, Mw8.3, 632km depth), the Chishima

  2. Total Ambient Dose Equivalent Buildup Factor Determination for Nbs04 Concrete.

    Science.gov (United States)

    Duckic, Paulina; Hayes, Robert B

    2018-06-01

    Buildup factors are dimensionless multiplicative factors required by the point kernel method to account for scattered radiation through a shielding material. The accuracy of the point kernel method is strongly affected by the correspondence of analyzed parameters to experimental configurations, which is attempted to be simplified here. The point kernel method has not been found to have widespread practical use for neutron shielding calculations due to the complex neutron transport behavior through shielding materials (i.e. the variety of interaction mechanisms that neutrons may undergo while traversing the shield) as well as non-linear neutron total cross section energy dependence. In this work, total ambient dose buildup factors for NBS04 concrete are calculated in terms of neutron and secondary gamma ray transmission factors. The neutron and secondary gamma ray transmission factors are calculated using MCNP6™ code with updated cross sections. Both transmission factors and buildup factors are given in a tabulated form. Practical use of neutron transmission and buildup factors warrants rigorously calculated results with all associated uncertainties. In this work, sensitivity analysis of neutron transmission factors and total buildup factors with varying water content has been conducted. The analysis showed significant impact of varying water content in concrete on both neutron transmission factors and total buildup factors. Finally, support vector regression, a machine learning technique, has been engaged to make a model based on the calculated data for calculation of the buildup factors. The developed model can predict most of the data with 20% relative error.

  3. A new approximating formula for calculating gamma-ray buildup factors in multilayer shields

    International Nuclear Information System (INIS)

    Assad, A.; Chiron, M.; Nimal, J.C.; Diop, C.M.; Ridoux, P.

    1999-01-01

    This study proposes a new approximating formula for calculating gamma-ray buildup factors in multilayer shields. The formula combines the buildup factors of single-layer shields with products and quotients. The feasibility of the formula for reproducing the buildup factors was tested by using point isotropic buildup factors calculated with the SN1D discrete ordinates code as reference data. The dose buildup factors of single-, double-, and multilayer shields composed of water, aluminum, iron, and lead were calculated for a spherical geometry in the energy range between 10 MeV and 40 keV and for total thicknesses of up to 30 mean free paths. The calculation of the buildup factors takes into account the bound electron effect of Compton scattering (incoherent scattering), the coherent scattering, the pair production, and the secondary sources of bremsstrahlung and fluorescence. The tests have shown that the approximating formula reproduces the reference data of double-layer shields very well for most cases. With the same parameters and with a new physical consideration that takes into account in a global way the degradation of the gamma-ray energy spectrum, the buildup factors of three- and five-layer shields were also very well reproduced

  4. MAGNETIC ENERGY BUILDUP FOR RELATIVISTIC MAGNETAR GIANT FLARES

    International Nuclear Information System (INIS)

    Yu Cong

    2011-01-01

    Motivated by coronal mass ejection studies, we construct general relativistic models of a magnetar magnetosphere endowed with strong magnetic fields. The equilibrium states of the stationary, axisymmetric magnetic fields in the magnetar magnetosphere are obtained as solutions of the Grad-Shafranov equation in a Schwarzschild spacetime. To understand the magnetic energy buildup in the magnetar magnetosphere, a generalized magnetic virial theorem in the Schwarzschild metric is newly derived. We carefully address the question whether the magnetar magnetospheric magnetic field can build up sufficient magnetic energy to account for the work required to open up the magnetic field during magnetar giant flares. We point out the importance of the Aly-Sturrock constraint, which has been widely studied in solar corona mass ejections, as a reference state in understanding magnetar energy storage processes. We examine how the magnetic field can possess enough energy to overcome the Aly-Sturrock energy constraint and open up. In particular, general relativistic (GR) effects on the Aly-Sturrock energy constraint in the Schwarzschild spacetime are carefully investigated. It is found that, for magnetar outbursts, the Aly-Sturrock constraint is more stringent, i.e., the Aly-Sturrock energy threshold is enhanced due to the GR effects. In addition, neutron stars with greater mass have a higher Aly-Sturrock energy threshold and are more difficult to erupt. This indicates that magnetars are probably not neutron stars with extreme mass. For a typical neutron star with mass of 1-2 M sun , we further explore the cross-field current effects, caused by the mass loading, on the possibility of stored magnetic field energy exceeding the Aly-Sturrock threshold.

  5. Three-Dimensional Unsteady Simulation of a Modern High Pressure Turbine Stage Using Phase Lag Periodicity: Analysis of Flow and Heat Transfer

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali; Luk, Daniel F.; Chen, Jen-Ping

    2010-01-01

    Unsteady three-dimensional RANS simulations have been performed on a highly loaded transonic turbine stage and results are compared to steady calculations as well as experiment. A low Reynolds number k- turbulence model is employed to provide closure for the RANS system. A phase-lag boundary condition is used in the periodic direction. This allows the unsteady simulation to be performed by using only one blade from each of the two rows. The objective of this paper is to study the effect of unsteadiness on rotor heat transfer and to glean any insight into unsteady flow physics. The role of the stator wake passing on the pressure distribution at the leading edge is also studied. The simulated heat transfer and pressure results agreed favorably with experiment. The time-averaged heat transfer predicted by the unsteady simulation is higher than the heat transfer predicted by the steady simulation everywhere except at the leading edge. The shock structure formed due to stator-rotor interaction was analyzed. Heat transfer and pressure at the hub and casing were also studied. Thermal segregation was observed that leads to the heat transfer patterns predicted by steady and unsteady simulations to be different.

  6. Pressure Indication of 3013 Inner Containers Using Digital Radiography

    International Nuclear Information System (INIS)

    HENSEL, SJ

    2004-01-01

    Plutonium bearing materials packaged for long term storage per the Department of Energy Standard 3013 (DOE-STD-3013) are required to be examined periodically in a non-destructive manner (i.e. without compromising the storage containers) for pressure buildup. Radiography is the preferred technology for performing the examinations. The concept is to measure and record the container lid position. As a can pressurizes the lid will deflect outward and thus provide an indication of the internal pressure. A radiograph generated within 30 days of creation of each storage container serves as the baseline from which future surveillance examinations will be compared. A problem with measuring the lid position was discovered during testing of a digital radiography system. The solution was to provide a distinct feature upon the lower surface of the container lid from which the digital radiography system could easily track the lid position

  7. Opacity Build-up in Impulsive Relativistic Sources

    International Nuclear Information System (INIS)

    Granot, Jonathan; Cohen-Tanugi, Johann; Silva, Eduardo do Couto e

    2007-01-01

    Opacity effects in relativistic sources of high-energy gamma-rays, such as gamma-ray bursts (GRBs) or Blazars, can probe the Lorentz factor of the outflow as well as the distance of the emission site from the source, and thus help constrain the composition of the outflow (protons, pairs, magnetic field) and the emission mechanism. Most previous works consider the opacity in steady state. Here we study the effects of the time dependence of the opacity to pair production (γγ → e + e - ) in an impulsive relativistic source, which may be relevant for the prompt gamma-ray emission in GRBs or flares in Blazars. We present a simple, yet rich, semi-analytic model for the time and energy dependence of the optical depth, τγγ, in which a thin spherical shell expands ultra-relativistically and emits isotropically in its own rest frame over a finite range of radii, R 0 (le) R (le) R 0 +ΔR. This is particularly relevant for GRB internal shocks. We find that in an impulsive source (ΔR ∼ 0 ), while the instantaneous spectrum (which is typically hard to measure due to poor photon statistics) has an exponential cutoff above the photon energy (var e psilon)1(T) where tγγ((var e psilon)1) = 1, the time integrated spectrum (which is easier to measure) has a power-law high-energy tail above the photon energy (var e psilon)1* ∼ (var e psilon)1(ΔT) where ΔT is the duration of the emission episode. Furthermore, photons with energies (var e psilon) > (var e psilon)1* are expected to arrive mainly near the onset of the spike in the light curve or flare, which corresponds to the short emission episode. This arises since in such impulsive sources it takes time to build-up the (target) photon field, and thus the optical depth τγγ((var e psilon)) initially increases with time and (var e psilon)1(T) correspondingly decreases with time, so that photons of energy (var e psilon) > (var e psilon)1* are able to escape the source mainly very early on while (var e psilon)1(T) > (var

  8. The build-up and characterization of nuclear burn-up wave in a fast ...

    Indian Academy of Sciences (India)

    K V Anoop

    2018-02-07

    Feb 7, 2018 ... evaluating the quality of the wave by the researchers working in the field of nuclear burn-up wave build-up and propagation. Keywords. ... However, there are concerns relating to the nuclear safety, ... Simulation studies have.

  9. Development and buildup of a biomass by various yeasts on whey

    Energy Technology Data Exchange (ETDEWEB)

    Zalashka, L S; Samtsevich, S A; Bakunowicz, L

    1967-01-01

    Of the 113 strains of yeast grown on whey, 29 assimilated lactose by fermentation and 23 by direct souring. The most productive were Candida humicola and C. curvata. The buildup of biomass averaged 18 to 30 g./1. medium.

  10. Sustained effect of resistance training on blood pressure and hand grip strength following a detraining period in elderly hypertensive women: a pilot study

    Directory of Open Access Journals (Sweden)

    Nascimento D da C

    2014-01-01

    Full Text Available Dahan da Cunha Nascimento,1,5,8 Ramires Alsamir Tibana,1,8 Franklin M Benik,2 Keila Elizabeth Fontana,3 Frederico Ribeiro Neto,8 Frederico Santos de Santana,5,8 Leopoldo Santos-Neto,4 Renato André Sousa Silva,1,5,6 Alessandro Oliveira Silva,1,7 Darlan Lopes Farias,1,7 Sandor Balsamo,4,5,8 Jonato Prestes1 1Postgraduate Program in Physical Education, Catholic University of Brasilia, Brasilia, Brazil; 2Department of Kinesiology and Sports Studies Graduate Program, Eastern Illinois University, Charleston, IL, USA; 3Faculty of Physical Education, University of Brasilia, Brasilia, Brazil; 4Graduate Program in Medical Sciences of the University of Brasilia, School of Medicine and Rheumatology Service, University Hospital of Brasilia (HUB, Brasilia, Brazil; 5Department of Physical Education, University Center Euro American University Center, Brasilia, Brazil; 6Center of Excellence in Medicine of Exercise (CEMEx, Brasilia, Brazil; 7Center University of Brasilia (UNICEUB, Brasilia, Brazil; 8Strength Training and Health Research Group (GEPEEFS, Brasilia, Brazil Introduction: Hypertension is the most prevalent modifiable risk factor with a high prevalence among older adults. Exercise is a nonpharmacological treatment shown to benefit all patients with hypertension. Objective: This study examined the effects of a 14-week moderate intensity resistance training program (RT on the maintenance of blood pressure and hand grip strength during an extended detraining period in elderly hypertensive women. Methods: Twelve hypertensive sedentary elderly women completed 14 weeks of whole body RT at a moderate perceived exertion following a detraining period of 14 weeks. Results: Following the training period, participants demonstrated an increase in absolute hand grip strength (P=0.001, relative hand grip strength (P=0.032 and a decrease of systolic (P=0.001, diastolic (P=0.008, and mean blood pressure (P=0.002 when compared to pre-exercise values. In addition, these

  11. Prediction of wax buildup in 24 inch cold, deep sea oil loading line

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.; Sattler, R.E.; Tolonen, W.J.; Pitchford, A.C.

    1981-10-01

    When designing pipelines for cold environments, it is important to know how to predict potential problems due to wax deposition on the pipeline's inner surface. The goal of this work was to determine the rate of wax buildup and the maximum, equlibrium wax thickness for a North Sea field loading line. The experimental techniques and results used to evaluate the waxing potential of the crude oil (B) are described. Also, the theoretic model which was used for predicting the maximum wax deposit thickness in the crude oil (B) loading pipeline at controlled temperatures of 40 F (4.4 C) and 100 F (38 C), is illustrated. Included is a recommendation of a procedure for using hot oil at the end of a tanker loading period in order to dewax the crude oil (B) line. This technique would give maximum heating of the pipeline and should be followed by shutting the hot oil into the pipeline at the end of the loading cycle which will provide a hot oil soaking to help soften existing wax. 14 references.

  12. Analysis of the build-up of semi and non volatile organic compounds on urban roads.

    Science.gov (United States)

    Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna

    2011-04-01

    Vehicular traffic in urban areas may adversely affect urban water quality through the build-up of traffic generated semi and non volatile organic compounds (SVOCs and NVOCs) on road surfaces. The characterisation of the build-up processes is the key to developing mitigation measures for the removal of such pollutants from urban stormwater. An in-depth analysis of the build-up of SVOCs and NVOCs was undertaken in the Gold Coast region in Australia. Principal Component Analysis (PCA) and Multicriteria Decision tools such as PROMETHEE and GAIA were employed to understand the SVOC and NVOC build-up under combined traffic scenarios of low, moderate, and high traffic in different land uses. It was found that congestion in the commercial areas and use of lubricants and motor oils in the industrial areas were the main sources of SVOCs and NVOCs on urban roads, respectively. The contribution from residential areas to the build-up of such pollutants was hardly noticeable. It was also revealed through this investigation that the target SVOCs and NVOCs were mainly attached to particulate fractions of 75-300 μm whilst the redistribution of coarse fractions due to vehicle activity mainly occurred in the >300 μm size range. Lastly, under combined traffic scenario, moderate traffic with average daily traffic ranging from 2300 to 5900 and average congestion of 0.47 were found to dominate SVOC and NVOC build-up on roads. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Determination of contamination-free build-up for 60Co

    International Nuclear Information System (INIS)

    Higgins, P.D.; Sibata, CH.; Paliwal, B.R.

    1985-01-01

    Experimental verification of the difference between absorbed dose in tissue and the collision fraction of kerma requires precise knowledge of the absorbed dose curve, particularly in the build-up and build-down regions. A simple method from direct measurement of contamination-free build-up for 60 Co, which should also be applicable for most of the photon energies commonly employed for treatment, is presented. It is shown that the contribution from air-scattered electrons to the surface dose may be removed by extrapolating measurements of build-up to zero field size. The remaining contribution to contamination from the collimators and other source-related hardware may be minimised by measuring these build-up curves sufficiently far from the source. These results were tested by measuring the build-up using a magnet to sweep scattered electrons from the primary photon beam and by measuring the surface dose in the limit of an evacuated beam path. The relative dose at zero depth in polystyrene was found to be approximately 8.9+-0.3% of the dose at the depth of maximum build-up. (author)

  14. Plasma density enhancement in atmospheric-pressure dielectric-barrier discharges by high-voltage nanosecond pulse in the pulse-on period: a PIC simulation

    International Nuclear Information System (INIS)

    Sang Chaofeng; Sun Jizhong; Wang Dezhen

    2010-01-01

    A particle-in-cell (PIC) plus Monte Carlo collision simulation is employed to investigate how a sustainable atmospheric pressure single dielectric-barrier discharge responds to a high-voltage nanosecond pulse (HVNP) further applied to the metal electrode. The results show that the HVNP can significantly increase the plasma density in the pulse-on period. The ion-induced secondary electrons can give rise to avalanche ionization in the positive sheath, which widens the discharge region and enhances the plasma density drastically. However, the plasma density stops increasing as the applied pulse lasts over certain time; therefore, lengthening the pulse duration alone cannot improve the discharge efficiency further. Physical reasons for these phenomena are then discussed.

  15. Plasma density enhancement in atmospheric-pressure dielectric-barrier discharges by high-voltage nanosecond pulse in the pulse-on period: a PIC simulation

    Science.gov (United States)

    Sang, Chaofeng; Sun, Jizhong; Wang, Dezhen

    2010-02-01

    A particle-in-cell (PIC) plus Monte Carlo collision simulation is employed to investigate how a sustainable atmospheric pressure single dielectric-barrier discharge responds to a high-voltage nanosecond pulse (HVNP) further applied to the metal electrode. The results show that the HVNP can significantly increase the plasma density in the pulse-on period. The ion-induced secondary electrons can give rise to avalanche ionization in the positive sheath, which widens the discharge region and enhances the plasma density drastically. However, the plasma density stops increasing as the applied pulse lasts over certain time; therefore, lengthening the pulse duration alone cannot improve the discharge efficiency further. Physical reasons for these phenomena are then discussed.

  16. Activity build-up in the primary circuit of pressurized water reactors

    International Nuclear Information System (INIS)

    Sachse, G.; Mittag, I.

    1986-01-01

    Based upon international literature, the following topics are reviewed: research and development efforts; release, transport, and deposition of radioactive corrosion products under primary circuit conditions; experimental results in test and technical systems; possibilities of controlling radiation fields in nuclear power plants by water-chemical measures, decontamination, and high-temperature filtration. (author)

  17. Problems of Gas Pressure Build-up in Casing String of UGS and Gas Wells

    Directory of Open Access Journals (Sweden)

    Peter Sovius

    2006-10-01

    Full Text Available This paper consists of three basic parts. The opening part is a brief description of problems associated with the secondary untightness of UGS wells (Underground Gas Storages and gas wells generally.The main part of the paper is composed of some cases that we have met in our company. Solution proposals of various cases are also supplied in this part. Separate problem situations are described in terms of finding out an untight point and also a testing result and consequential removing of untightness.The conclusion includes knowledge summary that were taken by solution of complicatedsituations connected with well non-hermeticity.

  18. Understanding the build-up of SMBH and Galaxies

    Science.gov (United States)

    Carrera, Francisco; Georgakakis, Antonis; Ueda, Yoshihiro; Akylas, Thanassis; Lanzuisi, Giorgio; Castello, N.

    2015-09-01

    . The excellent survey capabilities of Athena/WFI (effective area, angular resolution, field of view) will allow to measure the incidence of feedback in the shape of warm absorbers and Ultra Fast Outflows among the general population of AGN, as well as to complete the census of black hole growth by detecting and characterising significant samples of the most heavily obscured (including Compton thick) AGN, to redshifts z~3-4. The outstanding spectral throughput and resolution of Athena/X-IFU will permit measuring the energetics of those outflows to assess their influence on their host galaxies. The demographics of the heavily obscured and outflowing populations relative to their hosts are fundamental for understanding how major black hole growth events relate to the build-up of galaxies.

  19. An Inverse Function Least Square Fitting Approach of the Buildup Factor for Radiation Shielding Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Je [Sejong Univ., Seoul (Korea, Republic of); Alkhatee, Sari; Roh, Gyuhong; Lee, Byungchul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Dose absorption and energy absorption buildup factors are widely used in the shielding analysis. The dose rate of the medium is main concern in the dose buildup factor, however energy absorption is an important parameter in the energy buildup factors. ANSI/ANS-6.4.3-1991 standard data is widely used based on interpolation and extrapolation by means of an approximation method. Recently, Yoshida's geometric progression (GP) formulae are also popular and it is already implemented in QAD code. In the QAD code, two buildup factors are notated as DOSE for standard air exposure response and ENG for the response of the energy absorbed in the material itself. In this paper, a new least square fitting method is suggested to obtain a reliable buildup factors proposed since 1991. Total 4 datasets of air exposure buildup factors are used for evaluation including ANSI/ANS-6.4.3-1991, Taylor, Berger, and GP data. The standard deviation of the fitted data are analyzed based on the results. A new reverse least square fitting method is proposed in this study in order to reduce the fitting uncertainties. It adapts an inverse function rather than the original function by the distribution slope of dataset. Some quantitative comparisons are provided for concrete and lead in this paper, too. This study is focused on the least square fitting of existing buildup factors to be utilized in the point-kernel code for radiation shielding analysis. The inverse least square fitting method is suggested to obtain more reliable results of concave shaped dataset such as concrete. In the concrete case, the variance and residue are decreased significantly, too. However, the convex shaped case of lead can be applied to the usual least square fitting method. In the future, more datasets will be tested by using the least square fitting. And the fitted data could be implemented to the existing point-kernel codes.

  20. Passive containment cooling system with drywell pressure regulation for boiling water reactor

    Science.gov (United States)

    Hill, P.R.

    1994-12-27

    A boiling water reactor is described having a regulating valve for placing the wetwell in flow communication with an intake duct of the passive containment cooling system. This subsystem can be adjusted to maintain the drywell pressure at (or slightly below or above) wetwell pressure after the initial reactor blowdown transient is over. This addition to the PCCS design has the benefit of eliminating or minimizing steam leakage from the drywell to the wetwell in the longer-term post-LOCA time period and also minimizes the temperature difference between drywell and wetwell. This in turn reduces the rate of long-term pressure buildup of the containment, thereby extending the time to reach the design pressure limit. 4 figures.

  1. The period of the day affects the twenty-four hour blood pressure response to an acute combined exercise session in Brazilian jiu jitsu athletes

    Directory of Open Access Journals (Sweden)

    Rafaello Pinheiro Mazzoccante

    2015-09-01

    Full Text Available AbstractThe purpose of this study was to compare the effect of a combined exercise session performed at different periods of the day on the 24h blood pressure (BP response. Anaerobic threshold (AT and 12 repetition maximum (12RM tests were evaluated in nine Brazilian jiu-jitsu athletes (male (22±3.7 y; 176±5.0 cm; 73.4±9.7 kg; 6.8±2.1 % body fat. Four experimental sessions were performed: resistance exercise followed by aerobic exercise [Morning (MornS and Afternoon (AfternS] and Control (C [Morning and Afternoon]. The morning sessions were conducted at 09:00 a.m. and the afternoon sessions were conducted at 3:00 p.m. The resistance exercise consisted of three sets at 90% of a 12RM for six resistance exercises. The aerobic exercise consisted of 15min at 90% of the AT. Blood pressure (BP was measured before, during and 1h (Microlife(r BP3A1C after the performance of exercises in laboratory, and then during daily activities for the succeeding 23h by ambulatory BP monitoring (Dyna-MAPA(r. Analysis of the area under the curve (AUC indicated significant reductions in blood pressure parameters at various time points during the 24h monitoring period. For systolic BP (SBP, significantly lower values were shown following the morning session versus the control (MornS: 1756.2±100.8 vs. C: 1818.2±84.3 mmHg*15h; p < .05 and total-24h (MornS: 2695.8±143.3 vs. C: 2784.1±143.2 mmHg*24h; p < .05. The total-24h mean BP (MAP was also significantly lower following the morning session versus the control (MornS: 2015.7±121.2 vs. C: 2087.3±153.8 mmHg*24h; p < .05. There were significant differences in the sleeping AUC of SBP (AfternS: 883.6±27.0 vs. C: 965.2±67.9 mmHg*9h; p< .05, diastolic BP (DBP (AfternS: 481.4±30.9 vs. MornS: 552.9±34.2 and C: 562.1±52.3 mmHg*9h; p < .01 and MBP (AfternS: 651.9±22.4 vs. MornS: 708.7±43.1 and C: 726.9±64.7 mmHg*9h; p < .01. The combined exercise performed at different periods of the day contributed distinctly to

  2. Gamma-ray energy buildup factor calculations and shielding effects of some Jordanian building structures

    Science.gov (United States)

    Sharaf, J. M.; Saleh, H.

    2015-05-01

    The shielding properties of three different construction styles, and building materials, commonly used in Jordan, were evaluated using parameters such as attenuation coefficients, equivalent atomic number, penetration depth and energy buildup factor. Geometric progression (GP) method was used to calculate gamma-ray energy buildup factors of limestone, concrete, bricks, cement plaster and air for the energy range 0.05-3 MeV, and penetration depths up to 40 mfp. It has been observed that among the examined building materials, limestone offers highest value for equivalent atomic number and linear attenuation coefficient and the lowest values for penetration depth and energy buildup factor. The obtained buildup factors were used as basic data to establish the total equivalent energy buildup factors for three different multilayer construction styles using an iterative method. The three styles were then compared in terms of fractional transmission of photons at different incident photon energies. It is concluded that, in case of any nuclear accident, large multistory buildings with five layers exterior walls, style A, could effectively attenuate radiation more than small dwellings of any construction style.

  3. A model for the build-up of disordered material in ion bombarded Si

    International Nuclear Information System (INIS)

    Nelson, R.S.

    1977-01-01

    A new model based on experimental observation is developed for the build-up of disordered material in ion bombarded silicon. The model assumes that disordered zones are created in a background of migrating point defects, these zones then act as neutral sinks for such defects which interact with the zones and cause recrystallization. A simple steady state rate theory is developed to describe the build-up of disordered material with ion dose as a function of temperature. In general the theory predicts two distinct behaviour patterns depending on the temperature and the ion mass, namely a linear build-up with dose to complete disorder for heavy bombarding ions and a build-up to saturation at a relatively low level for light ions such as protons. However, in some special circumstances a transition region is predicted where the build-up of disorder approximately follows a (dose)sup(1/2) relationship before reverting to a linear behaviour at high dose. (author)

  4. Characterizing heavy metal build-up on urban road surfaces: Implication for stormwater reuse

    International Nuclear Information System (INIS)

    Liu, An; Liu, Liang; Li, Dunzhu; Guan, Yuntao

    2015-01-01

    Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a “fit-for-purpose” road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. - Highlights: • Heavy metal (HM) build-up varies with traffic and road surface conditions. • Traffic congestion and surface roughness exert a higher impact on HM build-up. • A “fit-for-purpose” strategy could suit urban road stormwater reuse

  5. Characterizing heavy metal build-up on urban road surfaces: Implication for stormwater reuse

    Energy Technology Data Exchange (ETDEWEB)

    Liu, An [Research Centre of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen (China); Cooperative Research and Education Centre for Environmental Technology, Kyoto University–Tsinghua University, 518055 Shenzhen (China); Liu, Liang; Li, Dunzhu [Research Centre of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen (China); Guan, Yuntao, E-mail: guanyt@tsinghua.edu.cn [Research Centre of Environmental Engineering and Management, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen (China); School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-05-15

    Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a “fit-for-purpose” road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. - Highlights: • Heavy metal (HM) build-up varies with traffic and road surface conditions. • Traffic congestion and surface roughness exert a higher impact on HM build-up. • A “fit-for-purpose” strategy could suit urban road stormwater reuse.

  6. Exposure Buildup Factors for Heavy Metal Oxide Glass: A Radiation Shield

    DEFF Research Database (Denmark)

    Manonara, S. R.; Hanagodimath, S. M.; Gerward, Leif

    2011-01-01

    Gamma ray exposure buildup factors for three Heavy Metal Oxide (HMO) glass systems, viz. PbO-Bi2O3-B2O3, PbO-B2O3, and Bi2O3-B2O3 glasses are presented. The computations were done by interpolation method using the Geometric Progression fitting formula and ANSI/ANS-6.4.3 library for the energy ran...... of graphs. Buildup factors of these HMO glasses cannot be found in any standard database, but they are useful for practical calculations in gamma ray shield designs, and they also, help to determine and control the thickness of the shielding material used.......Gamma ray exposure buildup factors for three Heavy Metal Oxide (HMO) glass systems, viz. PbO-Bi2O3-B2O3, PbO-B2O3, and Bi2O3-B2O3 glasses are presented. The computations were done by interpolation method using the Geometric Progression fitting formula and ANSI/ANS-6.4.3 library for the energy range...... from 0.015 to 15 MeV, up to penetration depths of 40 mfp (mean free path). The buildup factors have been studied as functions of incident photon energy and penetration depth. The variations in the buildup factor, for all the glass systems, in different energy regions; have been presented in the form...

  7. Noise Reduction, Atmospheric Pressure Admittance Estimation and Long-Period Component Extraction in Time-Varying Gravity Signals Using Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Linsong Wang

    2015-01-01

    Full Text Available Time-varying gravity signals, with their nonlinear, non-stationary and multi-scale characteristics, record the physical responses of various geodynamic processes and consist of a blend of signals with various periods and amplitudes, corresponding to numerous phenomena. Superconducting gravimeter (SG records are processed in this study using a multi-scale analytical method and corrected for known effects to reduce noise, to study geodynamic phenomena using their gravimetric signatures. Continuous SG (GWR-C032 gravity and barometric data are decomposed into a series of intrinsic mode functions (IMFs using the ensemble empirical mode decomposition (EEMD method, which is proposed to alleviate some unresolved issues (the mode mixing problem and the end effect of the empirical mode decomposition (EMD. Further analysis of the variously scaled signals is based on a dyadic filter bank of the IMFs. The results indicate that removing the high-frequency IMFs can reduce the natural and man-made noise in the data, which are caused by electronic device noise, Earth background noise and the residual effects of pre-processing. The atmospheric admittances based on frequency changes are estimated from the gravity and the atmospheric pressure IMFs in various frequency bands. These time- and frequency-dependent admittance values can be used effectively to improve the atmospheric correction. Using the EEMD method as a filter, the long-period IMFs are extracted from the SG time-varying gravity signals spanning 7 years. The resulting gravity residuals are well correlated with the gravity effect caused by the _ polar motion after correcting for atmospheric effects.

  8. Dynamic model for tritium build-up at NPP with RBMK type reactors and its enviromental beraviour

    International Nuclear Information System (INIS)

    Badyaev, V.V.; Egorov, Yu.A.; Ivanov, E.A.; Stegachev, G.F.; Tolstykh, V.D.

    1982-01-01

    A model of tritium production dynamics for a high power NPP with RBMK type reactors is proposed and investigated. The main ''skeleton'' model structure for forecasting tritium buildup at a NPP and its exchange with the environment has been singled out at a heuristic level. Decomposition and layout of the units have been performed by global functional relations of the investigated objects (NPP and environment). the model accounts for only oxidized tritium forms. Water exchange between the NPP subsystems and environment is the main mechanism for tritium migration. The model does not account for scheduled periodic maintenance work effects, presence of stagnant zones in the station circuits, fuel burn-up, etc. The parametric identification method applied in the model makes the model adaptable to particular situations and considered systems of the NPP and environment. Completing the model with necessary and sufficient experimental data one can pass to certain forecasting problems and to NPP control as a tritium source in the environment

  9. Contour Crafting Simulation Plan for Lunar Settlement Infrastructure Build-Up

    Science.gov (United States)

    Khoshnevis, B.; Carlson, A.; Leach N.; Thangavelu, M.

    2016-01-01

    Economically viable and reliable building systems and tool sets are being sought, examined and tested for extraterrestrial infrastructure buildup. This project focused on a unique architecture weaving the robotic building construction technology with designs for assisting rapid buildup of initial operational capability Lunar and Martian bases. The project aimed to study new methodologies to construct certain crucial infrastructure elements in order to evaluate the merits, limitations and feasibility of adapting and using such technologies for extraterrestrial application. Current extraterrestrial settlement buildup philosophy holds that in order to minimize the materials needed to be flown in, at great transportation costs, strategies that maximize the use of locally available resources must be adopted. Tools and equipment flown as cargo from Earth are proposed to build required infrastructure to support future missions and settlements on the Moon and Mars.

  10. Build-up of actinides in irradiated fuel rods of the ET-RR-1 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Adib, M.; Naguib, K.; Morcos, H.N

    2001-09-01

    The content concentrations of actinides are calculated as a function of operating reactor regime and cooling time at different percentage of fuel burn-up. The build-up transmutation equations of actinides content in an irradiated fuel are solved numerically .A computer code BAC was written to operate on a PC computer to provide the required calculations. The fuel element of 10% {sup 235}U enrichment of ET-RR-1 reactor was taken as an example for calculations using the BAC code. The results are compared with other calculations for the ET-RR-1 fuel rod. An estimation of fissile build-up content of a proposed new fuel of 20% {sup 235}U enrichment for ET-RR-1 reactor is given. The sensitivity coefficients of build-up plutonium concentrations as a function of cross-section data uncertainties are also calculated.

  11. Paleochannel and beach-bar palimpsest topography as initial substrate for coralligenous buildups offshore Venice, Italy.

    Science.gov (United States)

    Tosi, Luigi; Zecchin, Massimo; Franchi, Fulvio; Bergamasco, Andrea; Da Lio, Cristina; Baradello, Luca; Mazzoli, Claudio; Montagna, Paolo; Taviani, Marco; Tagliapietra, Davide; Carol, Eleonora; Franceschini, Gianluca; Giovanardi, Otello; Donnici, Sandra

    2017-05-02

    We provide a model for the genesis of Holocene coralligenous buildups occurring in the northwestern Adriatic Sea offshore Venice at 17-24 m depth. High-resolution geophysical surveys and underwater SCUBA diving reconnaissance revealed meandering shaped morphologies underneath bio-concretionned rocky buildups. These morphologies are inferred to have been inherited from Pleistocene fluvial systems reactivated as tidal channels during the post- Last Glacial Maximum transgression, when the study area was a lagoon protected by a sandy barrier. The lithification of the sandy fossil channel-levee systems is estimated to have occurred at ca. 7 cal. ka BP, likely due to the interaction between marine and less saline fluids related to onshore freshwater discharge at sea through a sealed water-table. The carbonate-cemented sandy layers served as nucleus for subsequent coralligenous buildups growth.

  12. Hypertriglyceridemic Waist Phenotype and Changes in the Fasting Glycemia and Blood Pressure in Children and Adolescents Over One-Year Follow-Up Period.

    Science.gov (United States)

    Costa, Priscila Ribas de Farias; Assis, Ana Marlúcia Oliveira; Cunha, Carla de Magalhães; Pereira, Emile Miranda; Jesus, Gabriela Dos Santos de; Silva, Lais Eloy Machado da; Alves, Wilanne Pinheiro de Oliveira

    2017-07-01

    The hypertriglyceridemic waist (HTW) phenotype is defined as the simultaneous presence of increased waist circumference (WC) and serum triglycerides (TG) levels and it has been associated with cardiometabolic risk in children and adolescents. The objective was to evaluate the influence of HTW phenotype in the fasting glycemia and blood pressure in children and adolescents over one-year follow-up period. It is a cohort study involving 492 children and adolescents from 7 to 15 years old, both genders, who were submitted to anthropometric, biochemical and clinical evaluation at the baseline, and also after 6 and 12 months of follow-up. Generalized Estimating Equation (GEE) models were calculated to evaluate the longitudinal influence of the HTW phenotype in the glycemia and blood pressure over one-year. It was observed a prevalence of 10.6% (n = 52) of HTW phenotype in the students. The GEE models identified that students with HTW phenotype had an increase of 3.87 mg/dl in the fasting glycemia mean (CI: 1.68-6.05) and of 3.67mmHg in the systolic blood pressure (SBP) mean (CI: 1.55-6.08) over one-year follow-up, after adjusting for confounding variables. The results of this study suggest that HTW phenotype is a risk factor for longitudinal changes in glycemia and SBP in children and adolescents over one-year follow-up period. O fenótipo de cintura hipertrigliceridêmica (CHT) é definido como a presença simultânea de circunferência de cintura (CC) e níveis séricos de triglicérides (TG) aumentados e tem sido associado com risco cardiometabólico em crianças e adolescentes. Avaliar a influência do fenótipo CHT na glicemia de jejum e na pressão arterial em crianças e adolescentes em um período de acompanhamento de um ano. Trata-se de um estudo de coorte envolvendo 492 crianças e adolescentes de 7 a 15 anos de ambos os sexos, que foram submetidos à avaliação antropométrica, bioquímica e clínica no início e também após 6 e 12 meses de seguimento. Os

  13. Hydropower build-up and the timber floating in Northern Finland after the Second World War

    Energy Technology Data Exchange (ETDEWEB)

    Haenninen, N. (Univ. of Oulu, Thule Inst. (Finland)). email: niko.hanninen@oulu.fi

    2009-07-01

    During the Second World War, Finland lost a substantial amount of built and yet un-built hydropower capacity to Soviet Union due to loss of Karelia. The most significant energy user at the time was the forest industry, especially paper and pulp mills, which had to replace this loss and to secure uninterrupted supply of energy in the future; otherwise the industry could not realise their expansion plans. One solution was to harness the still untouched northern waters for the service of the industry and society in large. However, these rivers served already the forest industry in another way, as transport routes in floating of timber. Vast waterways had made the emergence of forest industry in Finland possible. Transportation of timber from distant forests, located more than hundreds of kilometres away from the mills, was possible using rivers and lakes. Especially in Northern Finland the industry had to rely on floating as the railway network was less extensive than in some other parts of the country. The objective of this paper is to study closer, how the emergence of vast hydropower dams in these northern rivers from late 1940's to 1970's changed the transportation of timber. Road transportation in particular could not compete with floating because of their higher costs and the lack of suitable trucks and roads, but this changed after the war. Despite the fact that expanding industries consumed more and more timber, the role of floating decreased. But how did these ratios change during this period? Did the build-up of hydropower plants contribute to this shift of timber transportations from waterways to the land? Salmon and logs did not fit on the same river, the fishermen had to yield in the end. Did the hydropower plants do the same to the floaters

  14. Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation

    International Nuclear Information System (INIS)

    Hong, Nian; Zhu, Panfeng; Liu, An

    2017-01-01

    Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. - Highlights: • A model was developed to simulate heavy metal build-up loads on urban roads. • This model is based on artificial neural networks. • Land use fractions was used to model build-up loads on different particle sizes. • The maps of heavy metal spatial distribution and ecological risk were generated. • This model can be used for effective stormwater reuse strategy implementation. - Development of a robust modelling approach to mapping heavy metals build-up and their ecological risks for stormwater reuse safety.

  15. Source mechanisms of persistent shallow earthquakes during eruptive and non-eruptive periods between 1981 and 2011 at Mount St. Helens, Washington

    Science.gov (United States)

    Lehto, Heather L.; Roman, Diana C.; Moran, Seth C.

    2013-01-01

    Shallow seismicity between 0 and 3-km depth has persisted at Mount St. Helens, Washington (MSH) during both eruptive and non-eruptive periods for at least the past thirty years. In this study we investigate the source mechanisms of shallow volcano-tectonic (VT) earthquakes at MSH by calculating high-quality hypocenter locations and fault plane solutions (FPS) for all VT events recorded during two eruptive periods (1981–1986 and 2004–2008) and two non-eruptive periods (1987–2004 and 2008–2011). FPS show a mixture of normal, reverse, and strike-slip faulting during all periods, with a sharp increase in strike-slip faulting observed in 1987–1997 and an increase in normal faulting in 1998–2004. FPS P-axis orientations show a ~ 90° rotation with respect to regional σ1 (N23°E) during 1981–1986 and 2004–2008, bimodal orientations (~ N-S and ~ E-W) during 1987–2004, and bimodal orientations at ~ N-E and ~ S-W from 2008–2011. We interpret these orientations to likely be due to pressurization accompanying the shallow intrusion and subsequent eruption of magma as domes during 1981–1986 and 2004–2008 and the buildup of pore pressure beneath a seismogenic volume (located at 0–1 km) with a smaller component due to the buildup of tectonic forces during 1987–2004 and 2008–2011.

  16. A method of the sensitivity analysis of build-up and decay of actinides

    International Nuclear Information System (INIS)

    Mitani, Hiroshi; Koyama, Kinji; Kuroi, Hideo

    1977-07-01

    To make sensitivity analysis of build-up and decay of actinides, mathematical methods related to this problem have been investigated in detail. Application of time-dependent perturbation technique and Bateman method to sensitivity analysis is mainly studied. For the purpose, a basic equation and its adjoint equation for build-up and decay of actinides are systematically solved by introducing Laplace and modified Laplace transforms and their convolution theorems. Then, the mathematical method of sensitivity analyses is formulated by the above technique; its physical significance is also discussed. Finally, application of eigenvalue-method is investigated. Sensitivity coefficients can be directly calculated by this method. (auth.)

  17. Basic principle of constant q/sub a/ current build-up in tokamaks

    International Nuclear Information System (INIS)

    Kikuchi, M.

    1985-05-01

    An analytic expression is derived such that the current profile shape is kept constant during the current build-up phase in tokamaks. The required conductivity profile is parametrized by two externally controllable parameters, I/sub p/ and a/sub p/ in the case of the Gaussian current profile. It is shown that a Gaussian current profile can be maintained for a realistically broad conductivity profile by using the constant q/sub a/ current build-up method even under the condition of a high I/sub p/

  18. Pennsylvanian carbonate buildups, Paradox basin: Increasing reserves in heterogeneous, shallow-shelf reservoirs

    Science.gov (United States)

    Montgomery, S.L.; Chidsey, T.C.; Eby, D.E.; Lorenz, D.M.; Culham, W.E.

    1999-01-01

    Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer precipitous declines. An important new study focused on the detailed characterization of five separate reservoirs has resulted in significant information relevant to their future redevelopment. Completed assessment of Anasazi field suggests that phylloid algal mounds, the major productive buildup type in this area, consist of ten separate lithotypes and can be described in terms of a two-level reservoir system with an underlying high-permeability mound-core interval overlain by a lower permeability but volumetrically larger supramound (mound capping) interval. Reservoir simulations and related performance predictions indicate that CO2 flooding of these reservoirs should have considerable success in recovering remaining oil reserves.Productive carbonate buildups of Pennsylvanian age in the southern Paradox basin, Utah, contain up to 200 million bbl remaining oil potentially recoverable by enhanced recovery methods. These buildups comprise over 100 satellite fields to the giant Greater Aneth field, where secondary recovery operations thus far have been concentrated. Several types of satellite buildups exist and produce oil from the Desert Creek zone of the Paradox Formation. Many of the relevant fields have undergone early abandonment; wells in Desert Creek carbonate mounds commonly produce at very high initial rates (>1000 bbl/day) and then suffer

  19. Test for bacterial resistance build-up against plasma treatment

    International Nuclear Information System (INIS)

    Zimmermann, J L; Shimizu, T; Li, Y-F; Morfill, G E; Schmidt, H-U; Isbary, G

    2012-01-01

    It is well known that the evolution of resistance of microorganisms to a range of different antibiotics presents a major problem in the control of infectious diseases. Accordingly, new bactericidal ‘agents’ are in great demand. Using a cold atmospheric pressure (CAP) plasma dispenser operated with ambient air, a more than five orders of magnitude inactivation or reduction of Methicillin-resistant Staphylococcus aureus (MRSA; resistant against a large number of the tested antibiotics) was obtained in less than 10 s. This makes CAP the most promising candidate for combating nosocomial (hospital-induced) infections. To test for the occurrence and development of bacterial resistance against such plasmas, experiments with Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Enterococcus mundtii) were performed. The aim was to determine quantitative limits for primary (naturally) or secondary (acquired) resistance against the plasma treatment. Our results show that E. coli and E. mundtii possess no primary resistance against the plasma treatment. By generating four generations of bacteria for every strain, where the survivors of the plasma treatment were used for the production of the next generation, a lower limit to secondary resistance was obtained. Our results indicate that CAP technology could contribute to the control of infections in hospitals, in outpatient care and in disaster situations, providing a new, fast and efficient broad-band disinfection technology that is not constrained by bacterial resistance mechanisms. (paper)

  20. Effect of heat build-up on carbon emissions in chimato compost piles ...

    African Journals Online (AJOL)

    A study was conducted to determine impacts of heat build-up of chimato compost piles TD0, TD20, TD40, TD50, TD60, TD80 and TD100, made by blending maize stalks with 0, 20, 40, 50, 60, 80 and 100% Tithonia diversifolia, respectively, on carbon losses and emissions during composting. Compost piles temperatures ...

  1. "Testing during Study Insulates against the Buildup of Proactive Interference": Correction

    Science.gov (United States)

    Szpunar, Karl K.; McDermott, Kathleen B.; Roedigger, Henry L., III

    2009-01-01

    Reports an error in "Testing during study insulates against the buildup of proactive interference" by Karl K. Szpunar, Kathleen B. McDermott and Henry L. Roediger III ("Journal of Experimental Psychology: Learning, Memory, and Cognition," 2008[Nov], Vol 34[6], 1392-1399). Incorrect figures were printed due to an error in the…

  2. Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy-absorption...

  3. Effect of finite sample dimensions and total scatter acceptance angle on the gamma ray buildup factor

    International Nuclear Information System (INIS)

    Singh, Sukhpal; Kumar, Ashok; Singh, Charanjeet; Thind, Kulwant Singh; Mudahar, Gurmel S.

    2008-01-01

    The simultaneous variation of gamma ray buildup factors with absorber thickness (up to 6.5 mfp) and total scatter acceptance angle (which is the sum of incidence and exit beam divergence) in the media of high volume flyash concrete and water was studied experimentally using a point isotropic 137 Cs source

  4. Monte Carlo simulation of photon buildup factors for shielding materials in diagnostic x-ray facilities

    International Nuclear Information System (INIS)

    Kharrati, Hedi; Agrebi, Amel; Karoui, Mohamed Karim

    2012-01-01

    Purpose: A simulation of buildup factors for ordinary concrete, steel, lead, plate glass, lead glass, and gypsum wallboard in broad beam geometry for photons energies from 10 keV to 150 keV at 5 keV intervals is presented. Methods: Monte Carlo N-particle radiation transport computer code has been used to determine the buildup factors for the studied shielding materials. Results: An example concretizing the use of the obtained buildup factors data in computing the broad beam transmission for tube potentials at 70, 100, 120, and 140 kVp is given. The half value layer, the tenth value layer, and the equilibrium tenth value layer are calculated from the broad beam transmission for these tube potentials. Conclusions: The obtained values compared with those calculated from the published data show the ability of these data to predict shielding transmission curves. Therefore, the buildup factors data can be combined with primary, scatter, and leakage x-ray spectra to provide a computationally based solution to broad beam transmission for barriers in shielding x-ray facilities.

  5. Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

    African Journals Online (AJOL)

    The study examined the effect of fallow generational cycles on the buildup of nutrients in the soil. Fallow sequence of 1st, 2nd, 3rd, 4th and 5th generations were studied. The quadrat approach of sampling was employed to collect soil samples (surface and subsurface) from five plots of 10m x 10m across the five fallow ...

  6. Monte Carlo simulation of photon buildup factors for shielding materials in diagnostic x-ray facilities.

    Science.gov (United States)

    Kharrati, Hedi; Agrebi, Amel; Karoui, Mohamed Karim

    2012-10-01

    A simulation of buildup factors for ordinary concrete, steel, lead, plate glass, lead glass, and gypsum wallboard in broad beam geometry for photons energies from 10 keV to 150 keV at 5 keV intervals is presented. Monte Carlo N-particle radiation transport computer code has been used to determine the buildup factors for the studied shielding materials. An example concretizing the use of the obtained buildup factors data in computing the broad beam transmission for tube potentials at 70, 100, 120, and 140 kVp is given. The half value layer, the tenth value layer, and the equilibrium tenth value layer are calculated from the broad beam transmission for these tube potentials. The obtained values compared with those calculated from the published data show the ability of these data to predict shielding transmission curves. Therefore, the buildup factors data can be combined with primary, scatter, and leakage x-ray spectra to provide a computationally based solution to broad beam transmission for barriers in shielding x-ray facilities.

  7. A 4-year clinical evaluation of direct composite build-ups for space closure after orthodontic treatment.

    Science.gov (United States)

    Demirci, Mustafa; Tuncer, Safa; Öztaş, Evren; Tekçe, Neslihan; Uysal, Ömer

    2015-12-01

    To evaluate the medium-term clinical performance of direct composite build-ups for diastema closures and teeth recontouring using a nano and a nanohybrid composite in combination with three- or two-step etch-and-rinse adhesives following treatment with fixed orthodontic appliances. A total of 30 patients (mean age, 19.5 years) received 147 direct composite additions for teeth recontouring and diastema closures. A nano and a nanohybrid composite (Filtek Supreme XT and CeramX Duo) were bonded to tooth structure by using a three-step (Scotchbond Multipurpose) or a two-step (XP Bond) etch and rinse adhesive. Ten out of 147 composite build-ups (composite addition) constituted tooth recontouring cases, and the remaining 137 constituted diastema closure cases. The restorations were evaluated by two experienced, calibrated examiners according to modified Ryge criteria at the following time intervals: baseline, 1, 2, 3, and 4 years. The 4-year survival rates were 92.8 % for Filtek Supreme XT/Scotchbond Multi-Purpose Plus and 93 % for CeramX Duo/XP Bond. Only ten restorations failed (5 Filtek Supreme XT and 5 CeramX Duo). Statistical analysis revealed no significant differences between the two composite-adhesive combinations with respect to color match, marginal discoloration, wear/loss of anatomical form, caries formation, marginal adaptation, and surface texture on comparing the five time periods (baseline, 1, 2, 3, and 4 years) The 4-year survival rates in the present study were favorable. The restorations exhibited excellent scores with regard to color match, marginal adaptation, surface texture, marginal discoloration, wear/loss of anatomical form, and caries formation, after 4 years of clinical evaluation. Clinical relevance An alternative clinical approach for correcting discrepancies in tooth size and form, such as performing direct composite restorations following fixed orthodontic treatment, may be an excellent and minimally invasive treatment.

  8. A study of the energy absorption and exposure buildup factors of some anti-inflammatory drugs

    International Nuclear Information System (INIS)

    Ekinci, Neslihan; Kavaz, Esra; Özdemir, Yüksel

    2014-01-01

    Human radiation exposure is increasing due to radiation development in science and technology. The development of radioprotective agents is important for protecting patients from the side effects of radiotherapy and for protecting the public from unwanted irradiation. Radioprotective agents are used to reduce the damage caused by radiation in healthy tissues. There are several classes of radioprotective compounds that are under investigation. Analgesics and anti-inflammatory compounds are being considered for treating or preventing the effects of damage due to radiation exposure, or for increasing the chance of survival after exposure to a high dose of radiation. In this study, we investigated the radioprotective effects of some analgesic and anti-inflammatory compounds by evaluating buildup factors. The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) were calculated to select compounds in a 0.015–15 MeV energy region up to a penetration depth of 40 mfp (mean free path). Variations of EABF and EBF with incident photon energy and penetration depth elements were also investigated. Significant variations in both EABF and EBF values were observed for several compounds at the moderate energy region. At energies below 0.15 MeV, EABF and EBF values increased with decreasing equivalent atomic number (Z eq ) of the samples. In addition, EABF and EBF were the largest for ibuprofen, aspirin, paracetamol, naproxen and ketoprofen at 0.05 and 0.06 MeV, respectively, and the EABF value was 0.1 MeV for aceclofenac. From these results, we concluded that the buildup of photons is less for aceclofenac compared to other materials. - Highlights: • Buildup factors of anti-inflammatory drugs have been calculated by a G-P fitting method. • Z eff of diclofenac was observed higher than other compounds. • It was found that buildup of photons is less for aceclofenac and diclofenac. • It would be appealing to use aceclofenac and diclofenac as radioprotective

  9. Dose discrepancies in the buildup region and their impact on dose calculations for IMRT fields

    International Nuclear Information System (INIS)

    Hsu, Shu-Hui; Moran, Jean M.; Chen Yu; Kulasekere, Ravi; Roberson, Peter L.

    2010-01-01

    Purpose: Dose accuracy in the buildup region for radiotherapy treatment planning suffers from challenges in both measurement and calculation. This study investigates the dosimetry in the buildup region at normal and oblique incidences for open and IMRT fields and assesses the quality of the treatment planning calculations. Methods: This study was divided into three parts. First, percent depth doses and profiles (for 5x5, 10x10, 20x20, and 30x30 cm 2 field sizes at 0 deg., 45 deg., and 70 deg. incidences) were measured in the buildup region in Solid Water using an Attix parallel plate chamber and Kodak XV film, respectively. Second, the parameters in the empirical contamination (EC) term of the convolution/superposition (CVSP) calculation algorithm were fitted based on open field measurements. Finally, seven segmental head-and-neck IMRT fields were measured on a flat phantom geometry and compared to calculations using γ and dose-gradient compensation (C) indices to evaluate the impact of residual discrepancies and to assess the adequacy of the contamination term for IMRT fields. Results: Local deviations between measurements and calculations for open fields were within 1% and 4% in the buildup region for normal and oblique incidences, respectively. The C index with 5%/1 mm criteria for IMRT fields ranged from 89% to 99% and from 96% to 98% at 2 mm and 10 cm depths, respectively. The quality of agreement in the buildup region for open and IMRT fields is comparable to that in nonbuildup regions. Conclusions: The added EC term in CVSP was determined to be adequate for both open and IMRT fields. Due to the dependence of calculation accuracy on (1) EC modeling, (2) internal convolution and density grid sizes, (3) implementation details in the algorithm, and (4) the accuracy of measurements used for treatment planning system commissioning, the authors recommend an evaluation of the accuracy of near-surface dose calculations as a part of treatment planning commissioning.

  10. Special Features of a 24-hour Arterial Blood Pressure Profile in Healthy Children During the Period of Adaptation to Studying at Different School Types

    Directory of Open Access Journals (Sweden)

    I. N. Zakharova

    2015-01-01

    Full Text Available Arterial hypertension in children is a serious socially important problem, because it holds a position within the top of cardiovascular diseases, beginning from the adolescent age. A timely start of preventive measures based on appropriate forecast assessment in children from risk groups will make it possible to reduce the disease burden in elder age groups. Research purpose. Based on comprehensive assessment of clinic-anamnestic, genealogic, psychologic data, peculiarities of daily profile of arterial tension in the course of adaptation to education in educational institutions, to characterize the markers and single out the factors associated with AT increase in children that are considered relatively healthy.Patients. On a voluntary basis, 199 children of 1–2 health groups were included in the research at the age of 10–12 years (11.3 ± 0.02 years who had just started their education at a cadet educational institution or middle school. The children did not have any complaints by the time of the research, nor did they have the necessity of taking medicines which could have an effect on the cardiovascular system and acute infectious diseases during the previous month.Methods. The research was carried out during the period from September 2013 until May 2014 in 2 successive stages corresponding to the first and second academic terms. The examination included clinic-anamnestic and genealogic methods, anthropometry, three-fold measuring of arterial pressure by Korotkoff’s method, 24-hour ECG and AP monitoring, monitoring of motion activity volume, study of general and school levels of anxiety and psychic tension, assessment of the vegetative nervous system condition, nature of exercise tolerance and volume of additional sports load, volume of additional academic load.Results. The most important predictors of AH development and elevated AP persistence in children aged 10–12 years of 1 and 2 health groups are: values of SAP and

  11. Intraocular pressure change over a habitual 24-hour period after changing posture or drinking water and related factors in normal tension glaucoma.

    Science.gov (United States)

    Sakata, Rei; Aihara, Makoto; Murata, Hiroshi; Saito, Hitomi; Iwase, Aiko; Yasuda, Noriko; Araie, Makoto

    2013-08-07

    We investigated the correlation between 24-hour IOP in the habitual (sitting during day and supine during night) position (H24h-IOP) and IOP after a postural-change test (PCT-IOP) and a water-drinking test (WDT-IOP). We also investigated ocular and systemic factors related with them in patients with normal tension glaucoma (NTG). Japanese NTG patients underwent H24h-IOP, PCT-IOP, and WDT-IOP measurements during a 24-hour period. Correlations among H24h-IOP, PCT-IOP, and WDT-IOP, and contributing ocular/systemic factors were investigated using regression analysis. There were 33 patients included. Peak H24h-IOP correlated positively with peak PCT-IOP and peak WDT-IOP (estimate = 0.422 and 0.419, P ≤ 0.010), and peak PCT-IOP with WDT-IOP (0.44, P = 0.002). Peak H24h-IOP correlated with refraction (0.36, P = 0.048) and negatively with the mean deviation (MD, -0.066, P = 0.031). MD and baseline IOP (the mean of H24h-IOP) correlated negatively with the H24h-IOP fluctuation (-0.058 and -0.58, P ≤ 0.050). Refraction, baseline IOP, mean blood pressure (mBP), and body mass index (BMI) correlated with peak PCT-IOP (0.23, 0.52, 0.097, and 0.32, respectively, P ≤ 0.038). PCT-IOP difference correlated with refraction and mBP (0.31 and 0.093, P ≤ 0.016) and negatively with age (-0.069, P = 0.003). Central corneal thickness, baseline IOP, age, and BMI correlated with peak WDT-IOP (0.030, 0.40, 0.088, and 0.26, P ≤ 0.050). Age and BMI correlated with WDT-IOP difference (0.086 and 0.20, P < 0.032). Positive correlation was found among the peaks of H24h-, PCT-, and WDT-IOP. A worse visual field was associated with higher peak and greater fluctuation of H24h-IOP in NTG. Several ocular/systemic factors were important in interpreting H24h-, PCT-, and WDT-IOP.

  12. Mechanism of the re-buildup phenomenon in moyamoya disease; Analysis of local cerebral hemodynamics with intra-arterial digital subtraction angiography

    Energy Technology Data Exchange (ETDEWEB)

    Touho, Hajime; Karasawa, Jun; Shishido, Hisashi; Morisako, Toshitaka; Yamada, Keisuke; Nagai, Shigeki; Shibamoto, Kenji [Osaka Neurological Institute, Osaka (Japan)

    1990-10-01

    The authors investigated the mechanism of the re-buildup phenomenon on electroencephalogram in 14 patients of moyamoya disease with superficial temporal artery-middle cerebral artery anastomosis. Visualization of the lateral view of the common carotid angiography was performed with intra-arterial digital subtraction angiography (IA-DSA), using a 4/sec x 3 sec + 2/sec x 5 sec + 1/sec x 5 sec film sequence. The catheter tip was inserted into C5/6 level and 250 mgl/ml of iopamidol was used as the contrast agent; 6 ml in total was injected over 1.5 seconds. Circulation times of the common carotid artery (C{sub 3} portion)-ascending parietal vein ({delta}TTP{sub s}) and common carotid artery-internal cerebral vein ({delta}TTP{sub D}) were measured before hyperventilation (HV), immediately after HV, and 3 minutes after HV during pre- and postoperative periods. {delta}TTP{sub D} in the preoperative period was prolonged by HV and was normalized at 3 minutes after HV but {delta}TTP{sub S} were prolonged immediately after and 3 minutes after HV. In the postoperative period, however, these values did not change significantly immediately after and 3 minutes after HV. These findings indicate that delayed cerebral blood flow response to HV is a pathogenetic factor of the re-buildup phenomenon in moyamoya disease. (author).

  13. Evaluation Of Liner Back-pressure Due To Concrete Pore Pressure At Elevated Temperatures

    International Nuclear Information System (INIS)

    James, R.J.; Rashid, Y.R.; Liu, A.S.; Gou, B.

    2006-01-01

    GE's latest evolution of the boiling water reactor, the ESBWR, has innovative passive design features that reduce the number and complexity of active systems, which in turn provide economic advantages while also increasing safety. These passive systems used for emergency cooling also mean that the primary containment system will experience elevated temperatures with longer durations than conventional plants in the event of design basis accidents. During a Loss of Coolant Accident (LOCA), the drywell in the primary containment structure for the ESBWR will be exposed to saturated steam conditions for up to 72 hours following the accident. A containment spray system may be activated that sprays the drywell area with water to condense the steam as part of the recovery operations. The liner back-pressure will build up gradually over the 72 hours as the concrete temperatures increase, and a sudden cool down could cause excessive differential pressure on the liner to develop. For this analysis, it is assumed that the containment spray is activated at the end of the 72-hour period. A back-pressure, acting between the liner and the concrete wall of the containment, can occur as a result of elevated temperatures in the concrete causing steam and saturated vapor pressures to develop from the free water remaining in the pores of the concrete. Additional pore pressure also develops under the elevated temperatures from the non-condensable gases trapped in the concrete pores during the concrete curing process. Any buildup of this pore pressure next to the liner, in excess of the drywell internal pressure, will act to push the liner away from the concrete with a potential for tearing at the liner anchorages. This paper describes the methods and analyses used to quantify this liner back-pressure so that appropriate measures are included in the design of the liner and anchorage system. A pore pressure model is developed that calculates the pressure distribution across the concrete

  14. Correlation between Co-60 and X-ray exposures on radiation-induced charge buildup in silicon-on-insulator buried oxides

    International Nuclear Information System (INIS)

    Schwank, James R.; Shaneyfelt, Marty R.; Loemker, Rhonda Ann; Draper, Bruce L.; Dodd, Paul E.; Witczak, StevenN C.; Riewe, Leonard Charles; Ferlet-Cavrois, V.; Paillet, P.; Leray, J.-L.; Fleetwood, D.M.

    2000-01-01

    Large differences in charge buildup in SOI buried oxides can result between x-ray and Co-60 irradiations. The effects of bias configuration and substrate type on charge buildup and hardness assurance issues are explored

  15. Exposure buildup factors for a cobalt-60 point isotropic source for single and two layer slabs

    International Nuclear Information System (INIS)

    Chakarova, R.

    1992-01-01

    Exposure buildup factors for point isotropic cobalt-60 sources are calculated by the Monte Carlo method with statistical errors ranging from 1.5 to 7% for 1-5 mean free paths (mfp) thick water and iron single slabs and for 1 and 2 mfp iron layers followed by water layers 1-5 mfp thick. The computations take into account Compton scattering. The Monte Carlo data for single slab geometries are approximated by Geometric Progression formula. Kalos's formula using the calculated single slab buildup factors may be applied to reproduce the data for two-layered slabs. The presented results and discussion may help when choosing the manner in which the radiation field gamma irradiation units will be described. (author)

  16. Calculation of point isotropic buildup factors of gamma rays for water and lead

    Directory of Open Access Journals (Sweden)

    A. S. H.

    2001-12-01

    Full Text Available   Exposure buildup factors for water and lead have been calculated by the Monte-Carlo method for an isotropic point source in an infinite homogeneous medium, using the latest cross secions available on the Internet. The types of interactions considered are ,photoelectric effect, incoherent (or bound-electron Compton. Scattering, coherent (or Rayleigh scattering and pair production. Fluorescence radiations have also been taken into acount for lead. For each material, calculations were made at 10 gamma ray energies in the 40 keV to 10 MeV range and up to penetration depths of 10 mean free paths at each energy point. The results presented in this paper can be considered as modified gamma ray exposure buildup factors and be used in radiation shielding designs.

  17. Energy buildup factor for ICRU 33 sphere surrounded by an air layer

    International Nuclear Information System (INIS)

    Ochiana, G.; Oncescu, M.

    1994-01-01

    The buildup factor due to the air surrounding an ICRU 33 sphere is a desirable quantity in the assessment of the air kerma rate for external exposure to gamma emitters distributed on the ground. A Monte Carlo algorithm has been developed to perform the photon transport calculation within the air layer around the sphere. The energy buildup factor due to the air layer has been calculated for an extended radioactive source - the contaminated ground. The transport of photons within the air layer surrounding a sphere -ICRU 33 phantom - is done by calculating separately the energies deposited by photons into the sphere when this one is in vacuum and when it is surrounded by the air, respectively. The results are given for an air layer of 100 m thickness and photon energy between 0.01 and 3.0 MeV. (Author) 1 Fig., 1 Tab., 9 Refs

  18. Gamma-ray energy absorption and exposure buildup factor studies in some human tissues with endometriosis

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.co [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Dogan, Bekir [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Ingec, Metin [Faculty of Medicine, Department of Obstetrics and Gynecology, Ataturk University, 25240 Erzurum (Turkey); Ekinci, Neslihan; Ozdemir, Yueksel [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)

    2011-02-15

    Human tissues with endometriosis have been analyzed in terms of energy absorption (EABF) and exposure (EBF) buildup factors using the five-parameter geometric progression (G-P) fitting formula in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). Chemical compositions of the tissue samples were determined using a wavelength dispersive X-ray fluorescence spectrometer (WDXRFS). Possible conclusions were drawn due to significant variations in EABF and EBF for the selected tissues when photon energy, penetration depth and chemical composition changed. Buildup factors so obtained may be of use when the method of choice for treatment of endometriosis is radiotherapy.

  19. Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Barale, M.; Guillodo, M.; Foucault, M., E-mail: Morgan.Barale@areva.com [AREVA NP SAS, Technical Centre, Le Creusot (France); Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C. [AREVA NP SAS, Chemistry and Radiochemistry Group, Paris (France); Corredera, G. [Electricite de France, Centre d' Expertise et d' Inspection dans les domaines de la Realisation et de l' Exploitation, Saint-Denis (France)

    2010-07-01

    Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N{sub 2}H{sub 4}, amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide

  20. Effect of tungsten-187 in primary coolant on dose rate build-up in Vandellos 2

    International Nuclear Information System (INIS)

    Fernandez Lillo, E.; Llovet, R.; Boronat, M.

    1994-01-01

    The present work proposes a relationship between the Cobalt-60 piping deposited activity and the relatively high levels of Tungsten-187 in the coolant of Vandellos 2. The conclusions of this work can be applicable to other plants, since it proposes a tool to estimate and quantify the contribution of stellite to the generation of Cobalt-60 and the radiation dose build-up. (authors). 7 figs., 6 refs

  1. Secondary side TSP deposit buildup: lab test investigation focused on electrokinetic considerations

    International Nuclear Information System (INIS)

    Barale, M.; Guillodo, M.; Foucault, M.; Ryckelynck, N.; Clinard, M-H.; Chahma, F.; Brun, C.; Corredera, G.

    2010-01-01

    Deposit buildup which caused the clogging of the 'foils' of the upper tube-support-plates (TSP) inside a PWR steam generator of French NPPs in 2006 presents certain similarities with deposits observed in lab tests performed in secondary coolant chemistry at the Technical Centre of AREVA NP in 2002. The mechanism of TSP clogging seems not to present obvious phenomenological links with the fouling of the free span of SG since deposits buildup is quite uniform and is currently related to a surface boiling effect due to the surface heat flux. A specific mechanism could account for TSP clogging. In particular, electrokinetic effects were investigated by EDF-CEIDRE and AREVA NP SAS in the framework of a lab test program started in 2007. The electrokinetic approach is to consider that the coupling of local hydrodynamic and surface electrochemistry could lead to the formation of a very localized and heterogeneous deposit at the leading edge between both TSP and SG tubing material. Electrokinetic effects can lead to the oxidation and/or the precipitation of ferrous ions and to a variation of the electrokinetic potential which can produce strong attraction of iron oxide colloids. These electrokinetic effects are dependent of the T/H and local hydrodynamic conditions and surface electrochemistry explaining. The objective of this EDF-AREVA lab test program is to investigate the role of secondary chemistry coolant (pH, DH, N 2 H 4 , amine, redox) and of the nature of materials (SS, Ni base alloy) on deposit buildup. Properties of oxide surface and zeta potential of oxidized metallic materials have been also determined at temperature to understand their potential contribution on mechanism of TSP clogging in secondary side chemistry coolant. In this paper, a set of specific experiments carried out in this frame have been presented and discussed, paying particular attention to the effects of electrokinetic considerations and surface charges at oxide-solution interfaces

  2. Neutron Buildup Factors Calculation for Support Vector Regression Application in Shielding Analysis

    International Nuclear Information System (INIS)

    Duckic, P.; Matijevic, M.; Grgic, D.

    2016-01-01

    In this paper initial set of data for neutron buildup factors determination using Support Vector Regression (SVR) method is prepared. The performance of SVR technique strongly depends on the quality of information used for model training. Thus it is very important to provide representable data to the SVR. SVR is a supervised type of learning so it demands data in the input/output form. In the case of neutron buildup factors estimation, the input parameters are the incident neutron energy, shielding thickness and shielding material and the output parameter is the neutron buildup factor value. So far the initial sets of data for different shielding configurations have been obtained using SCALE4.4 sequence SAS3. However, this results were obtained using group constants, thus the incident neutron energy was determined as the average value for each energy group. Obtained this way, the data provided to the SVR are fewer and therefore insufficient. More valuable information is obtained using SCALE6.2beta5 sequence MAVRIC which can perform calculations for the explicit incident neutron energy, which leads to greater maneuvering possibilities when active learning measures are employed, and consequently improves the quality of the developed SVR model.(author).

  3. Planar imaging quantification using 3D attenuation correction data and Monte Carlo simulated buildup factors

    International Nuclear Information System (INIS)

    Miller, C.; Filipow, L.; Jackson, S.; Riauka, T.

    1996-01-01

    A new method to correct for attenuation and the buildup of scatter in planar imaging quantification is presented. The method is based on the combined use of 3D density information provided by computed tomography to correct for attenuation and the application of Monte Carlo simulated buildup factors to correct for buildup in the projection pixels. CT and nuclear medicine images were obtained for a purpose-built nonhomogeneous phantom that models the human anatomy in the thoracic and abdominal regions. The CT transverse slices of the phantom were converted to a set of consecutive density maps. An algorithm was developed that projects the 3D information contained in the set of density maps to create opposing pairs of accurate 2D correction maps that were subsequently applied to planar images acquired from a dual-head gamma camera. A comparison of results obtained by the new method and the geometric mean approach based on published techniques is presented for some of the source arrangements used. Excellent results were obtained for various source - phantom configurations used to evaluate the method. Activity quantification of a line source at most locations in the nonhomogeneous phantom produced errors of less than 2%. Additionally, knowledge of the actual source depth is not required for accurate activity quantification. Quantification of volume sources placed in foam, Perspex and aluminium produced errors of less than 7% for the abdominal and thoracic configurations of the phantom. (author)

  4. Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation.

    Science.gov (United States)

    Hong, Nian; Zhu, Panfeng; Liu, An

    2017-12-01

    Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Processing ultrasonic inspection data from multiple scan patterns for turbine rotor weld build-up evaluations

    Science.gov (United States)

    Guan, Xuefei; Rasselkorde, El Mahjoub; Abbasi, Waheed; Zhou, S. Kevin

    2015-03-01

    The study presents a data processing methodology for weld build-up using multiple scan patterns. To achieve an overall high probability of detection for flaws with different orientations, an inspection procedure with three different scan patterns is proposed. The three scan patterns are radial-tangential longitude wave pattern, axial-radial longitude wave pattern, and tangential shear wave pattern. Scientific fusion of the inspection data is implemented using volume reconstruction techniques. The idea is to perform spatial domain forward data mapping for all sampling points. A conservative scheme is employed to handle the case that multiple sampling points are mapped to one grid location. The scheme assigns the maximum value for the grid location to retain the largest equivalent reflector size for the location. The methodology is demonstrated and validated using a realistic ring of weld build-up. Tungsten balls and bars are embedded to the weld build-up during manufacturing process to represent natural flaws. Flat bottomed holes and side drilled holes are installed as artificial flaws. Automatic flaw identification and extraction are demonstrated. Results indicate the inspection procedure with multiple scan patterns can identify all the artificial and natural flaws.

  6. Acetone as biomarker for ketosis buildup capability--a study in healthy individuals under combined high fat and starvation diets.

    Science.gov (United States)

    Prabhakar, Amlendu; Quach, Ashley; Zhang, Haojiong; Terrera, Mirna; Jackemeyer, David; Xian, Xiaojun; Tsow, Francis; Tao, Nongjian; Forzani, Erica S

    2015-04-22

    Ketogenic diets are high fat and low carbohydrate or very low carbohydrate diets, which render high production of ketones upon consumption known as nutritional ketosis (NK). Ketosis is also produced during fasting periods, which is known as fasting ketosis (FK). Recently, the combinations of NK and FK, as well as NK alone, have been used as resources for weight loss management and treatment of epilepsy. A crossover study design was applied to 11 healthy individuals, who maintained moderately sedentary lifestyle, and consumed three types of diet randomly assigned over a three-week period. All participants completed the diets in a randomized and counterbalanced fashion. Each weekly diet protocol included three phases: Phase 1 - A mixed diet with ratio of fat: (carbohydrate + protein) by mass of 0.18 or the equivalence of 29% energy from fat from Day 1 to Day 5. Phase 2- A mixed or a high-fat diet with ratio of fat: (carbohydrate + protein) by mass of approximately 0.18, 1.63, or 3.80 on Day 6 or the equivalence of 29%, 79%, or 90% energy from fat, respectively. Phase 3 - A fasting diet with no calorie intake on Day 7. Caloric intake from diets on Day 1 to Day 6 was equal to each individual's energy expenditure. On Day 7, ketone buildup from FK was measured. A statistically significant effect of Phase 2 (Day 6) diet was found on FK of Day 7, as indicated by repeated analysis of variance (ANOVA), F(2,20) = 6.73, p fat content and 90% fat content vs. 29% fat content (with p = 0.00159**, and 0.04435**, respectively), with no significant difference between diets with 79% fat content and 90% fat content. In addition, independent of the diet, a significantly higher ketone buildup capability of subjects with higher resting energy expenditure (R(2) = 0.92), and lower body mass index (R(2) = 0.71) was observed during FK.

  7. A collection of sub-daily pressure and temperature observations for the early instrumental period with a focus on the “year without a summer” 1816

    Czech Academy of Sciences Publication Activity Database

    Brugnara, Y.; Auchmann, R.; Broennimann, S.; Allan, R. J.; Auer, I.; Barriendos, M.; Bergström, H.; Bhend, J.; Brázdil, Rudolf; Compo, G. S.; Cornes, R. C.; Dominguez-Castro, F.; van Engelen, A. F. V.; Filipiak, J.; Holopainen, J.; Jourdain, S.; Kunz, M.; Luterbacher, J.; Maugeri, M.; Mercalli, L.; Moberg, A.; Mock, C. J.; Pichard, G.; Řezníčková, Ladislava; van der Schrier, G.; Slonosky, V.; Ustrnul, Z.; Valente, M. A.; Wypych, A.; Yin, X.

    2015-01-01

    Roč. 11, č. 8 (2015), s. 1027-1047 ISSN 1814-9324 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : daily-air temperature * sea-level pressure * volcanic eruptions * climate Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 3.638, year: 2015

  8. Layer-splitting technique for testing the recursive scheme for multilayer shields gamma ray buildup factors

    International Nuclear Information System (INIS)

    Alkhatib, Sari F.; Park, Chang Je; Jeong, Hae Yong; Lee, Yongdeok

    2016-01-01

    Highlights: • A simple formalism is suggested for the recursive approach and then it is used to produce buildup factors for certain multilayer shields. • The newly layer-splitting technique is implemented on the studied cases for testing the suggested formalism performance. • The buildup factors are generated using cubic polynomial fitting functions that are produced based on previous well-acknowledge data. - Abstract: This study illustrates the implementation of the newly suggested layer-splitting testing technique. This technique is introduced in order to be implemented in examining suggested formalisms for the recursive scheme (or iterative scheme). The recursive scheme is a concept used in treating and producing the gamma ray buildup factors in the case of multilayer shields. The layer-splitting technique simply enforces the scheme to treat a single layer of one material as two separated layers with similar characteristics. Thus it subjects the scheme to an abnormal definition of the multilayer shield that will test its performance in treating the successive layers. Thus, it will act as a method of verification for the approximations and assumptions taken in consideration. A simple formalism was suggested for the recursive scheme then the splitting technique was implemented on it. The results of implementing both the suggested formalism and the splitting technique are then illustrated and discussed. Throughout this study, cubic polynomial fitting functions were used to generate the data of buildup factors for the basic single-media that constitute the multilayer shields understudy. This study is limited to the cases of multiple shields consisting of repeated consecutive thin layers of lead–water and iron–water shields for 1 MeV gamma rays. The produced results of the buildup factor values through the implementation of the suggested formalism showed good consistency with the Monte Carlo simulation results of Lin and Jiang work. In the implementation of

  9. Variation of energy absorption buildup factors with incident photon energy and penetration depth for some commonly used solvents

    International Nuclear Information System (INIS)

    Singh, Parjit S.; Singh, Tejbir; Kaur, Paramjeet

    2008-01-01

    G.P. fitting method has been used to compute energy absorption buildup factor of some commonly used solvents such as acetonitrile (C 4 H 3 N), butanol (C 4 H 9 OH), chlorobenzene (C 6 H 5 Cl), diethyl ether (C 4 H 10 O), ethanol (C 2 H 5 OH), methanol (CH 3 OH), propanol (C 3 H 7 OH) and water (H 2 O) for the wide energy range (0.015-15.0 MeV) up to the penetration depth of 10 mean free path. The variation of energy absorption buildup factor with chemical composition as well as incident photon energy for the selected solvents has been studied. It has been observed that the maximum value of energy absorption buildup factors shifts to the slightly higher incident photon energy with the increase in equivalent atomic number of the solvent and the solvent with least equivalent atomic number possesses the maximum value of energy absorption buildup factor

  10. Document turn-over analysis to determine need of NPP construction in build-up structures of reinforced concrete

    International Nuclear Information System (INIS)

    Vojpe, D.K.; Lyubavin, V.K.

    1986-01-01

    Document turn-over to determine used of NPP construction in build-up structures of reinforced concrete is carried out. Ways of improving determination of needs of NPP construction board in the mentioned structures are pointed out

  11. Decomposition of litter and soil organic matter - Can we distinguish a mechanism for soil organic matter buildup ?

    International Nuclear Information System (INIS)

    Berg, B.; Johansson, M.B.; McClaugherty, C.; Virzo de Santo, A.; Ekbohm, G.

    1995-01-01

    This synthesis paper presents a model for estimating the buildup of soil organic matter in various types of coniferous forests. The knowledge used was obtained from a well-studied forest with good litterfall data, decomposition information and validation measurements of the soil organic matter layer. By constructing a simple model for litterfall, and the information on maximum decomposition levels for litter, we could estimate the annual increase in soil organic matter and extend this to encompass stand age. The validation measurement and the estimated amount of soil organic matter differed by about 8 or 26% over a 120-yr period, depending on the litterfall model. The estimated increased storage of soil organic matter as a consequence of climate change was found to be drastic. We thus found that the soil organic matter layer would grow about four times as fast as a result of the needle component only. This estimate was based on a comparison between latitudes with a difference of 17 degrees. 35 refs, 7 figs, 3 tabs

  12. Accumulation and dissipation of positive charges induced on a PMMA build-up cap of an ionisation chamber by 60Co gamma-ray irradiation

    International Nuclear Information System (INIS)

    Morishita, Y.; Takata, N.

    2013-01-01

    The signal current from an ionisation chamber with a PMMA build-up cap decreases with irradiation time due to electric fields produced by positive charges induced on the cap. In the present study, it was confirmed that the signal current decreases faster for irradiation using narrower 60 Co gamma-ray beams. This is because the number of secondary electrons that are emitted from surrounding materials and penetrate the build-up cap is smaller in a narrower gamma-ray beam, so that fewer positive charges are neutralised. The ionisation chamber was first subjected to continuous gamma-ray irradiation for 24 h, following which it was irradiated with shorter periodic gamma-ray bursts while measuring the current signal. This allowed the coefficients of positive charge accumulation and dissipation to be determined. It was found that the dissipation coefficient has a large constant value during gamma-ray irradiation and decreases asymptotically to a small value after irradiation is stopped. From the coefficients, the minimum signal current was calculated, which is the value when accumulation and dissipation balance each other under continuous irradiation. The time required for the signal current to recover following irradiation was also calculated. (authors)

  13. Uncertainty analysis of pollutant build-up modelling based on a Bayesian weighted least squares approach

    International Nuclear Information System (INIS)

    Haddad, Khaled; Egodawatta, Prasanna; Rahman, Ataur; Goonetilleke, Ashantha

    2013-01-01

    Reliable pollutant build-up prediction plays a critical role in the accuracy of urban stormwater quality modelling outcomes. However, water quality data collection is resource demanding compared to streamflow data monitoring, where a greater quantity of data is generally available. Consequently, available water quality datasets span only relatively short time scales unlike water quantity data. Therefore, the ability to take due consideration of the variability associated with pollutant processes and natural phenomena is constrained. This in turn gives rise to uncertainty in the modelling outcomes as research has shown that pollutant loadings on catchment surfaces and rainfall within an area can vary considerably over space and time scales. Therefore, the assessment of model uncertainty is an essential element of informed decision making in urban stormwater management. This paper presents the application of a range of regression approaches such as ordinary least squares regression, weighted least squares regression and Bayesian weighted least squares regression for the estimation of uncertainty associated with pollutant build-up prediction using limited datasets. The study outcomes confirmed that the use of ordinary least squares regression with fixed model inputs and limited observational data may not provide realistic estimates. The stochastic nature of the dependent and independent variables need to be taken into consideration in pollutant build-up prediction. It was found that the use of the Bayesian approach along with the Monte Carlo simulation technique provides a powerful tool, which attempts to make the best use of the available knowledge in prediction and thereby presents a practical solution to counteract the limitations which are otherwise imposed on water quality modelling. - Highlights: ► Water quality data spans short time scales leading to significant model uncertainty. ► Assessment of uncertainty essential for informed decision making in water

  14. Fusion-product ash buildup in tokamak with radial electric field

    International Nuclear Information System (INIS)

    Downum, W.B.; Choi, C.K.; Miley, G.H.

    1979-01-01

    The buildup of thermalized fusion products (ash) in a tokamak can seriously limit burn times. Prior studies have concentrated on deposition profile effects on alpha particle transport in tokamaks but have not considered the effect on ash of radial electric fields (either created internally, e.g. due to high-energy alpha leakage, or generated externally). The present study focuses on this issue since it appears that electric fields might offer one approach to control of the ash. Approximate field and source profiles are used, based on prior calculations

  15. The application of the LTSN method in the evaluation of the buildup factor

    International Nuclear Information System (INIS)

    Rodriguez, Barbara A.; Borges, Volnei; Zabadal, Jorge R.

    2005-01-01

    In this paper the LTS N method is used to solve the transport equation for photons in a heterogeneous medium, assuming the Klein-Nishina scattering kernel as the scattering differential cross section as well the multigroup model in the wavelength variable. The flux density of photons and the parameters of the medium are used for the calculation of the exposure buildup factor. We present numerical simulations and comparisons with available results in the literature for different compositions containing water, iron and lead. (author)

  16. Reconstruction of pH and partial pressure of carbon dioxide during the Mesozoic era period using boron and oxygen isotopic compositions of fresh ammonoids & nautiloids

    Science.gov (United States)

    Kawahata, Hodaka; Fukushima, Ayaka; Moriya, Kazuyori; Ishikawa, Tsuyoshi; Suzuki, Atsushi; Tanabe, Kazushige

    2013-04-01

    The increase of partial pressure of carbon dioxide (pCO2) in the atmosphere induces global warming and ocean acidification at the modern condition. The reconstruction of pCO2 during the geological time is required together with proxy calibration by laboratory experiments to predict the future environments. Boron isotopic ratio is an excellent proxy for pH and the relevant partial pressure of carbon dioxide in the seawater (PCO2). This study is the first to quantify pH dependence of delta 11B of the ammonoids and nautiloids mainly in the Cretaceous and in Jurassic (70-162 Ma), which are expected to be much warmer due to higher PCO2. However, no reliable reconstruction data using foraminiferal delta 11B before Cenozoic era has been reported. We used the very fresh aragonite shells of ammonoids and nautiloids by big advantages. Since aragonite changes into secondary calcite by diagenesis, it is easy and effective to identify the degree of alteration at each sample by measuring calcite/aragonite ratio. Also we carefully conducted the assessment of secondary alteration from three perspectives: 1) Determination of calcite/aragonite ratio by X-ray diffraction (XRD), 2) Observation of microstructures of the nacreous layers by scanning electron microscope (SEM), and 3) Measurement of trace element contents and stable isotope ratios. We conducted high precision boron isotope analysis of biogenic carbonates with +/- 0.1 per mil reproducibility by adopting positive thermal ionization mass spectrometry (P-TIMS) methods. Also we analyzed delta 18O to estimate paleo-temperature, at which biogenic aragonite was formed. Combination of delta 11B and delta 18O of biogenic aragonite in 80 Ma and 86 Ma revealed that deeper dwellers showed lower delta 11B values, which corresponded to lower pH. This feature is consistent with those observed in the modern vertical water column. The respective shallow water temperature was 19.7 and 19.1 centigrade. Based on these results, the

  17. Radiation Build-Up Of High Energy Gamma In Shielding Of High Atomic Number

    International Nuclear Information System (INIS)

    Yuliati, Helfi; Akhadi, Mukhlis

    2000-01-01

    Research to observe effect of radiation build-up factor (b) in iron (Fe) and lead (Pb) for high energy gamma shielding from exp.137 Cs (E gamma : 662 keV) and exp.60 Co (E gamma : 1332 keV) sources has been carried out. Research was conducted bt counting of radiation intensity behind shielding with its thickness vary from 1 to 5 times of half value thickness (HVT). NaI (TI) detector which connected to multi channel analyzer (MCA) was used for the counting. Calculation result show that all of b value are near to 1 (b∼1) both for Fe and Pb. Without inserting b in calculation, from the experiment it was obtained HVT value of Fe for high gamma radiation of 662 and 1332 keV were : (12,94 n 0,03) mm and (17,33 n 0,01) mm with their deviation standards were 0,2% and 0,06% respectively. Value of HVT for Pb with the same energy were : (6,31 n 0,03) mm and (11,86 n 0,03) mm with their deviation standars were : 0,48% and 0,25% respectively. HVL concept could be applied directly to estimate shielding thickness of high atomic number of high energy gamma radiation, without inserting correction of radiation build-up factor

  18. Radiation Build-Up In Shielding Of Low Activity High Energia Gamma Source

    International Nuclear Information System (INIS)

    Helfi-Yuliati; Mukhlis-Akhadi

    2003-01-01

    Research to observe radiation build-up factor (b) in aluminium (Al), iron (Fe) and lead (Pb) for shielding of gamma radiation of high energy from 137 cs (E γ : 662 keV) source and 60 Co (E γ : 1332 keV) of low activity sources has been carried out. Al with Z =13 represent metal of low atomic number, Fe with Z =26 represent metal of medium atomic number, and Pb with Z = 82 represent metal of high atomic number. Low activity source in this research is source which if its dose rate decrease to 3 % of its initial dose rate became safe for the workers. Research was conducted by counting of radiation intensity behind shielding with its thickness vary from 1 to 5 times of half value thickness (HVT). NaI(TI) detector which connected to multi channel analyzer (MCA) was used for the counting. Calculation result show that all of b value are close to 1 (b ∼ 1) for all kinds of metals. No radiation build-up factor is required in estimating the shielding thickness from several kinds of metals for low activity of high energy gamma source. (author)

  19. Buildup factors for multilayer shieldings in deterministic methods and their comparison with Monte Carlo

    International Nuclear Information System (INIS)

    Listjak, M.; Slavik, O.; Kubovcova, D.; Vermeersch, F.

    2008-01-01

    In general there are two ways how to calculate effective doses. The first way is by use of deterministic methods like point kernel method which is implemented in Visiplan or Microshield. These kind of calculations are very fast, but they are not very convenient for a complex geometry with shielding composed of more then one material in meaning of result precision. In spite of this that programs are sufficient for ALARA optimisation calculations. On other side there are Monte Carlo methods which can be used for calculations. This way of calculation is quite precise in comparison with reality but calculation time is usually very large. Deterministic method like programs have one disadvantage -usually there is option to choose buildup factor (BUF) only for one material in multilayer stratified slabs shielding calculation problems even if shielding is composed from different materials. In literature there are proposed different formulas for multilayer BUF approximation. Aim of this paper was to examine these different formulas and their comparison with MCNP calculations. At first ware compared results of Visiplan and Microshield. Simple geometry was modelled - point source behind single and double slab shielding. For Build-up calculations was chosen Geometric Progression method (feature of the newest version of Visiplan) because there are lower deviations in comparison with Taylor fitting. (authors)

  20. The future role of reforestation in reducing buildup of atmospheric CO2

    International Nuclear Information System (INIS)

    Marland, G.

    1993-01-01

    Among the options posed for mitigating the buildup of atmospheric CO 2 is planting new forest areas to sequester carbon from the atmosphere. Among the questions of interest in modeling the global carbon cycle is the extent to which reforestation is likely to succeed in providing physical removal of CO 2 from the atmosphere. There are many strategies for using forest land to mitigate the atmospheric buildup of CO 2 : decreasing the rate at which forests are cleared for other land uses, increasing the density of carbon storage in existing forests, improving the rate and efficiency at which forest products are used in the place of other energy intensive products, substitution of renewable wood fuels for fossil fuels, improved management of forests and agroforestry, and increasing the amount of land in standing forest. Because increasing the area of forests has social, political, and economic limitations; in addition to physical limitations; it is hard to envision a large increase in forest area except where there are associated economic benefits. The authors speculation is that, over the next several decades, the forest strategies most likely to be pursued for the express purpose of CO 2 mitigation are those which provide more or more-efficient substitution of forest products for energy or energy-intensive resources and that the physical accumulation of additional carbon in forests will be of lesser importance

  1. French experience to reduce radiation field build-up and improve nuclear fuel performance

    International Nuclear Information System (INIS)

    Thomazet, J.; Beslu, P.; Noe, M.; Stora, J.P.

    1983-01-01

    Over these last years, considerable information has been obtained on primary coolant chemistry, activity build-up and nuclear fuel behavior. As of December 1982, twenty three 900 MWe type reactors were in operation in France and about 1.3 millions of rods had been loaded in power reactors among which six regions of 17x17 fuel assemblies had completed successfully their third cycle of irradiation with a lead assembly burn-up of 37,000 MWd/MtU. Visual examination shows that crud deposited on fuel clads is mostly thin or inexistent. This result is due to the appropriate B/Li coolant concentration control which is currently applied in French reactors since several years. Correlatively, radiation field build-up is minimized and excessive external corrosion has never been observed. Nevertheless for higher coolant temperature plants, where occurrence of nucleate boiling could increase crud deposition, and for load follow and high burn-up operation, an extensive programme is performed jointly by Commissariat a l'Energie Atomique (CEA), Electricite de France, FRAMATOME and FRAGEMA to reduce even more the radiation field. This programme, described in the paper, includes: loop tests; on site chemical and radiochemical surveys; radiation field measurements; on site fuel examination crud-scrapping, crud analysis and oxide thickness measurements; hot cells examination. Some key results are presented and discussed in this paper. (author)

  2. Quantitative assessment of the effect of corrosion product buildup on occupational exposure

    International Nuclear Information System (INIS)

    Divine, J.R.

    1982-10-01

    The program was developed to provide a method for predicting occupational exposures caused by the deposition of radioactive corrosion products outside the core of the primary system of an operating power reactor. This predictive capability will be useful in forecasting total occupational doses during maintenance, inspection, decontamination, waste treatment, and disposal. In developing a reliable predictive model, a better understanding of the parameters important to corrosion product film formation, corrosion product transport, and corrosion product film removal will be developed. This understanding can lead to new concepts in reactor design to minimize the buildup and transport of radioactive corrosion products or to improve methods of operation. To achieve this goal, three objectives were established to provide: (1) criteria for acceptable coolant sampling procedures and sampling equipment that will provide data which will be used in the model development; (2) a quantitative assessment of the effect of corrosion product deposits on occupational exposure; and (3) a model which describes the influence of flow, temperature, coolant chemistry, construction materials, radiation, and other operating parameters on the transport and buildup of corrosion products

  3. Electron Cloud Buildup Characterization Using Shielded Pickup Measurements and Custom Modeling Code at CESRTA

    CERN Document Server

    Crittenden, James A

    2013-01-01

    The Cornell Electron Storage Ring Test Accelerator experimental program includes investigations into electron cloud buildup, applying various mitigation techniques in custom vacuum chambers. Among these are two 1.1-m-long sections located symmetrically in the east and west arc regions. These chambers are equipped with pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of small holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. Carbon-coated, TiN-coated and uncoated aluminum chambers have been tested. Electron and positron beams of 2.1, 4.0 and 5.3 GeV with a variety of bunch populations and spacings in steps of 4 and 14 ns have been used. Here we report on results from the ECLOUD modeling code which highlight the sensitivity of these measurements to the physical phenomena determining cloud buildup such as the photoelectron produ...

  4. Buildup factors for multilayer shieldings in deterministic methods and their comparison with Monte Carlo

    International Nuclear Information System (INIS)

    Listjak, M.; Slavik, O.; Kubovcova, D.; Vermeersch, F.

    2009-01-01

    In general there are two ways how to calculate effective doses. The first way is by use of deterministic methods like point kernel method which is implemented in Visiplan or Microshield. These kind of calculations are very fast, but they are not very convenient for a complex geometry with shielding composed of more then one material in meaning of result precision. In spite of this that programs are sufficient for ALARA optimisation calculations. On other side there are Monte Carlo methods which can be used for calculations. This way of calculation is quite precise in comparison with reality but calculation time is usually very large. Deterministic method like programs have one disadvantage -usually there is option to choose buildup factor (BUF) only for one material in multilayer stratified slabs shielding calculation problems even if shielding is composed from different materials. In literature there are proposed different formulas for multilayer BUF approximation. Aim of this paper was to examine these different formulas and their comparison with MCNP calculations. At first ware compared results of Visiplan and Microshield. Simple geometry was modelled - point source behind single and double slab shielding. For Build-up calculations was chosen Geometric Progression method (feature of the newest version of Visiplan) because there are lower deviations in comparison with Taylor fitting. (authors)

  5. Periodical in-service inspection as part of individual program of quality assurance of steam generators and pressurizers of WWER 440 nuclear power plant

    International Nuclear Information System (INIS)

    Kawalec, M.

    1982-01-01

    The manufacturers of equipment for nuclear power plants in the Czechoslovak Socialist Republic are obligated to process so-called individual programs of quality assurance in order to secure the quality of selected equipment in nuclear power. These programmes should include the evaluation of the design of the individual equipments with regard to the implementation of in-service inspection. The main problems are discussed related to the processing of the program of quality assurance for the steam generator and pressurizer. To solve these problems it is necessary that the general project designer should make a classification of the components according to safety categories and that the manufacturers should determine the weak points of the design on the basis of an analysis of the design of individual component nodes. On the basis of such an analysis it is then necessary to evaluate the existing design of the scale of in-service inspections and to decide whether or not new inspection methods should be added. (Z.M.)

  6. Impact of eccentricity build-up and graveyard disposal Strategies on MEO navigation constellations

    Science.gov (United States)

    Radtke, Jonas; Domínguez-González, Raúl; Flegel, Sven K.; Sánchez-Ortiz, Noelia; Merz, Klaus

    2015-12-01

    With currently two constellations being in or close to the build-up phase, in a few years the Medium Earth Orbit (MEO) region will be populated with four complete navigation systems in relatively close orbital altitudes: The American GPS, Russian GLONASS, European Galileo, and Chinese BeiDou. To guarantee an appropriate visibility of constellation satellites from Earth, these constellations rely on certain defined orbits. For this, both the repeat pattern, which is basically defined by the semimajor axis and inclination, as well as the orbital planes, which are defined by the right ascension of ascending node, are determining values. To avoid an overcrowding of the region of interest, the disposal of satellites after their end-of-life is recommended. However, for the MEO region, no internationally agreed mitigation guidelines exist. Because of their distances to Earth, ordinary disposal manoeuvres leading to a direct or delayed re-entry due to atmospheric drag are not feasible: The needed fuel masses for such manoeuvres are by far above the reasonable limits and available fuel budgets. Thus, additional approaches have to be applied. For this, in general two options exist: disposal to graveyard orbits or the disposal to eccentricity build-up orbits. In the study performed, the key criterion for the graveyard strategy is that the disposed spacecraft must keep a safe minimum distance to the altitude of the active constellation on a long-term time scale of up to 200 years. This constraint imposes stringent requirements on the stability of the graveyard orbit. Similar disposals are also performed for high LEO satellites and disposed GEO payloads. The eccentricity build-up strategy on the other hand uses resonant effects between the Earth's geopotential, the Sun and the Moon. Depending on the initial conditions, these can cause a large eccentricity build-up, which finally can lead to a re-entry of the satellite. In this paper, the effects of applying either the first or

  7. Deep breathing exercises with positive expiratory pressure at a higher rate improve oxygenation in the early period after cardiac surgery--a randomised controlled trial.

    Science.gov (United States)

    Urell, Charlotte; Emtner, Margareta; Hedenström, Hans; Tenling, Arne; Breidenskog, Marie; Westerdahl, Elisabeth

    2011-07-01

    In addition to early mobilisation, a variety of breathing exercises are used to prevent postoperative pulmonary complications after cardiac surgery. The optimal duration of the treatment is not well evaluated. The aim of this study was to determine the effect of 30 versus 10 deep breaths hourly, while awake, with positive expiratory pressure on oxygenation and pulmonary function the first days after cardiac surgery. A total of 181 patients, undergoing cardiac surgery, were randomised into a treatment group, performing 30 deep breaths hourly the first postoperative days, or into a control group performing 10 deep breaths hourly. The main outcome measurement arterial blood gases and the secondary outcome pulmonary function, evaluated with spirometry, were determined on the second postoperative day. Preoperatively, both study groups were similar in terms of age, SpO(2), forced expiratory volume in 1s and New York Heart Association classification. On the second postoperative day, arterial oxygen tension (PaO(2)) was 8.9 ± 1.7 kPa in the treatment group and 8.1 ± 1.4 kPa in the control group (p = 0.004). Arterial oxygen saturation (SaO(2)) was 92.7 ± 3.7% in the treatment group and 91.1 ± 3.8% in the control group (p = 0.016). There were no differences in measured lung function between the groups or in compliance to the breathing exercises. Compliance was 65% of possible breathing sessions. A significantly increased oxygenation was found in patients performing 30 deep breaths the first two postoperative days compared with control patients performing 10 deep breaths hourly. These results support the implementation of a higher rate of deep breathing exercises in the initial phase after cardiac surgery. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

  8. Support vector regression model for the estimation of γ-ray buildup factors for multi-layer shields

    International Nuclear Information System (INIS)

    Trontl, Kresimir; Smuc, Tomislav; Pevec, Dubravko

    2007-01-01

    The accuracy of the point-kernel method, which is a widely used practical tool for γ-ray shielding calculations, strongly depends on the quality and accuracy of buildup factors used in the calculations. Although, buildup factors for single-layer shields comprised of a single material are well known, calculation of buildup factors for stratified shields, each layer comprised of different material or a combination of materials, represent a complex physical problem. Recently, a new compact mathematical model for multi-layer shield buildup factor representation has been suggested for embedding into point-kernel codes thus replacing traditionally generated complex mathematical expressions. The new regression model is based on support vector machines learning technique, which is an extension of Statistical Learning Theory. The paper gives complete description of the novel methodology with results pertaining to realistic engineering multi-layer shielding geometries. The results based on support vector regression machine learning confirm that this approach provides a framework for general, accurate and computationally acceptable multi-layer buildup factor model

  9. Calculation of gamma ray dose buildup factors in water for isotropic point, plane mono directional and line sources using MCNP code

    International Nuclear Information System (INIS)

    Atak, H.; Celikten, O. S.; Tombakoglu, M.

    2009-01-01

    Gamma ray dose buildup factors in water for isotropic point, plane mono directional and infinite/finite line sources were calculated using the MCNP code. The buildup factors are determined for gamma ray energies of 1, 2, 3 and 4 Mev and for shield thicknesses of 1, 2, 4 and 7 mean free paths. The calculated buildup factors were then fitted in the Taylor and Berger forms. For the line sources a buildup factor table was also constructed using the Sievert function and the constants in Taylor form derived in this study to compare with the Monte Carlo results. All buildup factors were compared with the tabulated data given in literature. In order to reduce the statistical errors on buildup factors, 'forced collision' option was used in the MCNP calculations.

  10. The Build-Up to Eruptive Solar Events Viewed as the Development of Chiral Systems

    Science.gov (United States)

    Martin, S. F.; Panasenco, O.; Berger, M. A.; Engvold, O.; Lin, Y.; Pevtsov, A. A.; Srivastava, N.

    2012-12-01

    When we examine the chirality or observed handedness of the chromospheric and coronal structures involved in the long-term build-up to eruptive events, we find that they evolve in very specific ways to form two and only two sets of large-scale chiral systems. Each system contains spatially separated components with both signs of chirality, the upper portion having negative (positive) chirality and the lower part possessing positive (negative) chirality. The components within a system are a filament channel (represented partially by sets of chromospheric fibrils), a filament (if present), a filament cavity, sometimes a sigmoid, and always an overlying arcade of coronal loops. When we view these components as parts of large-scale chiral systems, we more clearly see that it is not the individual components of chiral systems that erupt but rather it is the approximate upper parts of an entire evolving chiral system that erupts. We illustrate the typical pattern of build-up to eruptive solar events first without and then including the chirality in each stage of the build-up. We argue that a complete chiral system has one sign of handedness above the filament spine and the opposite handedness in the barbs and filament channel below the filament spine. If the spine has handedness, the observations favor its having the handedness of the filament cavity and coronal loops above. As the separate components of a chiral system form, we show that the system appears to maintain a balance of right-handed and left-handed features, thus preserving an initial near-zero net helicity. We further argue that the chiral systems allow us to identify key sites of energy transformation and stored energy later dissipated in the form of concurrent CMEs, erupting filaments and solar flares. Each individual chiral system may produce many successive eruptive events above a single filament channel. Because major eruptive events apparently do not occur independent of, or outside of, these unique

  11. Build-up Factor Calculation for Ordinary Concrete, Baryte Concrete and Blast-furnace Slugges Concrete as γ Radiation Shielding

    International Nuclear Information System (INIS)

    Isman MT; Elisabeth Supriatni; Tochrul Binowo

    2002-01-01

    Calculation of build up factor ordinary concrete, baryte concrete and blast-furnace sludge concrete have been carried out. The calculations have been carried out by dose rate measurement of Cs 137 source before and after passing through shielding. The investigated variables were concrete type, thickness of concrete and relative possession of concrete. Concrete type variables are ordinary concrete, baryte concrete and blast sludge furnace concrete. The thickness variables were 6, 12, 18, 24, 30 and 36 cm. The relative position variables were dose to the source and close to detector. The result showed that concrete type and position did not have significant effect to build-up factor value, while the concrete thickness (r) and the attenuation coefficient (μ) were influenced to the build-up factor. The higher μr value the higher build-up factor value. (author)

  12. Urban nonpoint source pollution buildup and washoff models for simulating storm runoff quality in the Los Angeles County.

    Science.gov (United States)

    Wang, Long; Wei, Jiahua; Huang, Yuefei; Wang, Guangqian; Maqsood, Imran

    2011-07-01

    Many urban nonpoint source pollution models utilize pollutant buildup and washoff functions to simulate storm runoff quality of urban catchments. In this paper, two urban pollutant washoff load models are derived using pollutant buildup and washoff functions. The first model assumes that there is no residual pollutant after a storm event while the second one assumes that there is always residual pollutant after each storm event. The developed models are calibrated and verified with observed data from an urban catchment in the Los Angeles County. The application results show that the developed model with consideration of residual pollutant is more capable of simulating nonpoint source pollution from urban storm runoff than that without consideration of residual pollutant. For the study area, residual pollutant should be considered in pollutant buildup and washoff functions for simulating urban nonpoint source pollution when the total runoff volume is less than 30 mm. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Buildup factor and mechanical properties of high-density cement mixed with crumb rubber and prompt gamma ray study

    Science.gov (United States)

    Aim-O, P.; Wongsawaeng, D.; Tancharakorn, S.; Sophon, M.

    2017-09-01

    High-density cement mixed with crumb rubber has been studied to be a gamma ray and neutron shielding material, especially for photonuclear reactions that may occur from accelerators where both types of radiation exist. The Buildup factors from gamma ray scattering, prompt and secondary gamma ray emissions from neutron capture and mechanical properties were evaluated. For buildup factor studies, two different geometries were used: narrow beam and broad beam. Prompt Gamma Neutron Activation Analysis (PGNAA) was carried out to determine the prompt and secondary gamma ray emissions. The compressive strength of samples was evaluated by using compression testing machine which was central point loading crushing test. The results revealed that addition of crumb rubber increased the buildup factor. Gamma ray spectra following PGNAA revealed no prompt or secondary gamma ray emission. Mechanical testing indicated that the compressive strength of the shielding material decreased with increasing volume percentage of crumb rubber.

  14. Energy absorption buildup factors of human organs and tissues at energies and penetration depths relevant for radiotherapy and diagnostics

    DEFF Research Database (Denmark)

    Manohara, S. R.; Hanagodimath, S. M.; Gerward, Leif

    2011-01-01

    Energy absorption geometric progression (GP) fitting parameters and the corresponding buildup factors have been computed for human organs and tissues, such as adipose tissue, blood (whole), cortical bone, brain (grey/white matter), breast tissue, eye lens, lung tissue, skeletal muscle, ovary......, testis, soft tissue, and soft tissue (4-component), for the photon energy range 0.015-15 MeV and for penetration depths up to 40 mfp (mean free path). The chemical composition of human organs and tissues is seen to influence the energy absorption buildup factors. It is also found that the buildup factor...... of human organs and tissues changes significantly with the change of incident photon energy and effective atomic number, Zeff. These changes are due to the dominance of different photon interaction processes in different energy regions and different chemical compositions of human organs and tissues...

  15. Aesthetic Closure of Maxillary and Mandibular Anterior Spaces Using Direct Composite Resin Build-Ups: A Case Report

    Directory of Open Access Journals (Sweden)

    Schick Simona-Georgiana

    2016-07-01

    Full Text Available The presence of multiple spaces in the anterior aesthetic zone can produce discomfort for patients and its treatment can be difficult for dental professionals. A variety of treatment options are available and these include orthodontic movement, prosthetic indirect restorations or direct composite resin build-ups. Among these, the closure of interdental spaces using composite build-ups combined with orthodontic treatment is considered to be most conservative. This type of treatment has several advantages like the maximum preservation of tooth substance (no tooth preparation, no need for anesthesia, no multiple time-consuming visits, no provisional restorations and also comparably low costs. Clinical Consideration: This case report describes the clinical restorative procedure of direct composite resin build-ups for the closure of multiple anterior spaces.

  16. The effect of plasma minor-radius expansion in the current build-up phase of a large tokamak

    International Nuclear Information System (INIS)

    Kobayashi, Tomofumi; Tazima, Teruhiko; Tani, Keiji; Tamura, Sanae

    1977-03-01

    A plasma simulation code has been developed to study the plasma current build-up process in JT-60. Plasma simulation is made with a model which represents well overall plasma behavior of the present-day tokamaks. The external electric circuit is taken into consideration in simulation calculation. An emphasis is placed on the simulation of minor-radius expansion of the plasma and behavior of neutral particles in the plasma during current build-up. A calculation with typical parameters of JT-60 shows a week skin distribution in the current density and the electron temperature, if the minor radius of the plasma expands with build-up of the plasma current. (auth.)

  17. THE XMM CLUSTER SURVEY: THE BUILD-UP OF STELLAR MASS IN BRIGHTEST CLUSTER GALAXIES AT HIGH REDSHIFT

    International Nuclear Information System (INIS)

    Stott, J. P.; Collins, C. A.; Hilton, M.; Capozzi, D.; Sahlen, M.; Lloyd-Davies, E.; Hosmer, M.; Liddle, A. R.; Mehrtens, N.; Romer, A. K.; Miller, C. J.; Stanford, S. A.; Viana, P. T. P.; Davidson, M.; Hoyle, B.; Kay, S. T.; Nichol, R. C.

    2010-01-01

    We present deep J- and K s -band photometry of 20 high redshift galaxy clusters between z = 0.8 and1.5, 19 of which are observed with the MOIRCS instrument on the Subaru telescope. By using near-infrared light as a proxy for stellar mass we find the surprising result that the average stellar mass of Brightest Cluster Galaxies (BCGs) has remained constant at ∼9 x 10 11 M sun since z ∼ 1.5. We investigate the effect on this result of differing star formation histories generated by three well-known and independent stellar population codes and find it to be robust for reasonable, physically motivated choices of age and metallicity. By performing Monte Carlo simulations we find that the result is unaffected by any correlation between BCG mass and cluster mass in either the observed or model clusters. The large stellar masses imply that the assemblage of these galaxies took place at the same time as the initial burst of star formation. This result leads us to conclude that dry merging has had little effect on the average stellar mass of BCGs over the last 9-10 Gyr in stark contrast to the predictions of semi-analytic models, based on the hierarchical merging of dark matter halos, which predict a more protracted mass build-up over a Hubble time. However, we discuss that there is potential for reconciliation between observation and theory if there is a significant growth of material in the intracluster light over the same period.

  18. Interpolation of Gamma-ray buildup Factors for Arbitrary Source Energies in the Vicinity of the K-edge

    International Nuclear Information System (INIS)

    Michieli, I.

    1998-01-01

    Recently, a new buildup factors approximation formula based on the expanded polynomial set (E-P function) was successfully introduced (Michieli 1994.) with the maximum approximation error below 4% throughout the standard data domain. Buildup factors interpolation in E-P function parameters for arbitrary source energies, near the K-edge in lead, was satisfactory. Maximum interpolation error, for lead, lays within 12% what appears to be acceptable for most Point Kernel application. 1991. Harima at. al., showed that, near the K-edge, fluctuation in energy of exposure rate attenuation factors i.e.: D(E)B(E, μ E r)exp(-μ E r), given as a function of penetration depth (r) in ordinary length units (not mfps.), is not nearly as great as that of buildup factors. That phenomenon leads to the recommendation (ANSI/ANS-6.4.3) that interpolations in that energy range should be made in the attenuation factors B(E, μ E r)exp(-μ E r) rather than in the buildup factors alone. In present article, such interpolation approach is investigated by applying it to the attenuation factors in lead, with E-P function representation of exposure buildup factors. Simple form of the E-P function leads to strait calculation of new function parameters for arbitrary source energy near the K-edge and thus allowing the same representation form of buildup factors as in the standard interpolation procedure. results of the interpolation are discussed and compared with those from standard approach. (author)

  19. A modified method of calculating the lateral build-up ratio for small electron fields

    International Nuclear Information System (INIS)

    Tyner, E; McCavana, P; McClean, B

    2006-01-01

    This note outlines an improved method of calculating dose per monitor unit values for small electron fields using Khan's lateral build-up ratio (LBR). This modified method obtains the LBR directly from the ratio of measured, surface normalized, electron beam percentage depth dose curves. The LBR calculated using this modified method more accurately accounts for the change in lateral scatter with decreasing field size. The LBR is used along with Khan's dose per monitor unit formula to calculate dose per monitor unit values for a set of small fields. These calculated dose per monitor unit values are compared to measured values to within 3.5% for all circular fields and electron energies examined. The modified method was further tested using a small triangular field. A maximum difference of 4.8% was found. (note)

  20. Internal background build-up measurements in CaF2:Mn thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Balasybrahmanyam, V.; Measures, M.P.

    1977-01-01

    Some problems associated with the internal background build-up (IBB) of CaF 2 :Mn thermoluminescent dosimeters are reported. As a result of an investigation of batches of the EG and G model 15 dosimeter it is considered that measurements using this type of dosimeter are accurate and reproducible once the IBB has been determined. However, the use of the Manufacturer's claimed average of 0.064 mR/day can lead to erroneous results when determining environmental background dose rates. The authors therefore urge a rigid quality control program by the manufacturer and suggest that purchasers should be supplied with IBB information of each batch of dosimeters. Meanwhile each user should be aware of the IBB problem and be extremely cautious when using these dosimeters for environmental monitoring purposes. (U.K.)

  1. Resonant laser power build-up in ALPS. A 'light-shining-through-walls' experiment

    International Nuclear Information System (INIS)

    Ehret, Klaus; Ghazaryan, Samvel; Frede, Maik

    2009-05-01

    The ALPS collaboration runs a light-shining-through-walls (LSW) experiment to search for photon oscillations into weakly interacting sub-eV particles (WISPs) inside of a superconducting HERA dipole magnet at the site of DESY. In this paper we report on the first successful integration of a large-scale optical cavity to boost the available power for WISP production in this type of experiments. The key elements are a frequency tunable narrow line-width continuous wave laser acting as the primary light source and an electronic feed-back control loop to stabilize the power build-up. We describe and characterize our apparatus and demonstrate the data analysis procedures on the basis of a brief exemplary run. (orig.)

  2. Early-Time Solution of the Horizontal Unconfined Aquifer in the Buildup Phase

    Science.gov (United States)

    Gravanis, Elias; Akylas, Evangelos

    2017-10-01

    We derive the early-time solution of the Boussinesq equation for the horizontal unconfined aquifer in the buildup phase under constant recharge and zero inflow. The solution is expressed as a power series of a suitable similarity variable, which is constructed so that to satisfy the boundary conditions at both ends of the aquifer, that is, it is a polynomial approximation of the exact solution. The series turns out to be asymptotic and it is regularized by resummation techniques that are used to define divergent series. The outflow rate in this regime is linear in time, and the (dimensionless) coefficient is calculated to eight significant figures. The local error of the series is quantified by its deviation from satisfying the self-similar Boussinesq equation at every point. The local error turns out to be everywhere positive, hence, so is the integrated error, which in turn quantifies the degree of convergence of the series to the exact solution.

  3. Electron-Cloud Build-up in the FNAL Main Injector

    International Nuclear Information System (INIS)

    Furman, M.A.

    2007-01-01

    We present a summary on ongoing simulation results for the electron-cloud buildup in the context of the proposed FNAL Main Injector (MI) intensity upgrade [1] in a fieldfree region at the location of the RFA electron detector [2]. By combining our simulated results for the electron flux at the vacuum chamber wall with the corresponding measurements obtained with the RFA we infer that the peak secondary electron yield (SEY) (delta) max is ∼> 1.4, and the average electron density is n e ∼> 10 10 m -3 at transition energy for the specific fill pattern and beam intensities defined below. The sensitivity of our results to several variables remains to be explored in order to reach more definitive results. Effects from the electron cloud on the beam are being investigated separately [3

  4. Particle simulation of pedestal buildup and study of pedestal scaling law in a quiescent plasma edge

    International Nuclear Information System (INIS)

    Chang, C.S.; Ku, S.; Weitzner, H.; Groebner, R.; Osborne, T.

    2005-01-01

    A discrete guiding-center particle code XGC (X-point included Guiding Center code) is used to study pedestal buildup and sheared E r formation in a quiescent plasma edge of a diverted tokamak. A neoclassical pedestal scaling law has been deduced, which shows that the density pedestal width is proportional to T i 1/2 M 1/2 /B t where T i is the ion temperature, M is ion mass and B t is the toroidal magnetic field. Dependence on the pedestal density or the poloidal magnetic field is found to be much weaker. Ion temperature pedestal is not as well defined as the density pedestal. Neoclassical electron transport rate, including the collisional heat exchange rate with ions, is too slow to be considered in the time scale of simulation (∼ 10 ms). (author)

  5. Resonant laser power build-up in ALPS-A 'light shining through a wall' experiment

    International Nuclear Information System (INIS)

    Ehret, Klaus; Frede, Maik; Ghazaryan, Samvel; Hildebrandt, Matthias; Knabbe, Ernst-Axel; Kracht, Dietmar; Lindner, Axel; List, Jenny; Meier, Tobias; Meyer, Niels; Notz, Dieter; Redondo, Javier; Ringwald, Andreas; Wiedemann, Guenter; Willke, Benno

    2009-01-01

    The ALPS Collaboration runs a 'light shining through a wall' (LSW) experiment to search for photon oscillations into 'weakly interacting sub-eV particles' (WISPs) inside of a superconducting HERA dipole magnet at the site of DESY. In this paper we report on the first successful integration of a large-scale optical resonant cavity to boost the available power for WISP production in this type of experiments. The key elements are a frequency tunable narrow line-width continuous wave laser acting as the primary light source and an electronic feed-back control loop to stabilize the power build-up. We describe and characterize our apparatus and demonstrate the data analysis procedures on the basis of a brief exemplary run.

  6. Influence of fast alpha diffusion and thermal alpha buildup on tokamak reactor performance

    International Nuclear Information System (INIS)

    Uckan, N.A.; Tolliver, J.S.; Houlberg, W.A.; Attenberger, S.E.

    1988-01-01

    The effect of fast alpha diffusion and thermal alpha accumulation on the confinement capability of a candidate Engineering Test Reactor plasma (Tokamak Ignition/Burn Experimental Reactor) in achieving ignition and steady-state driven operation has been assessed using both global and 1-1/2-dimensional transport models. Estimates are made of the threshold for radial diffusion of fast alphas and thermal alpha buildup. It is shown that a relatively low level of radial transport, when combined with large gradients in the fast alpha density, leads to a significant radial flow with a deleterious effect on plasma performance. Similarly, modest levels of thermal alpha concentration significantly influence the ignition and steady-state burn capability

  7. Differences in night-time and daytime ambulatory blood pressure when diurnal periods are defined by self-report, fixed-times, and actigraphy: Improving the Detection of Hypertension study.

    Science.gov (United States)

    Booth, John N; Muntner, Paul; Abdalla, Marwah; Diaz, Keith M; Viera, Anthony J; Reynolds, Kristi; Schwartz, Joseph E; Shimbo, Daichi

    2016-02-01

    To determine whether defining diurnal periods by self-report, fixed-time, or actigraphy produce different estimates of night-time and daytime ambulatory blood pressure (ABP). Over a median of 28 days, 330 participants completed two 24-h ABP and actigraphy monitoring periods with sleep diaries. Fixed night-time and daytime periods were defined as 0000-0600 h and 1000-2000 h, respectively. Using the first ABP period, within-individual differences for mean night-time and daytime ABP and kappa statistics for night-time and daytime hypertension (systolic/diastolic ABP≥120/70 mmHg and ≥135/85 mmHg, respectively) were estimated comparing self-report, fixed-time, or actigraphy for defining diurnal periods. Reproducibility of ABP was also estimated. Within-individual mean differences in night-time systolic ABP were small, suggesting little bias, when comparing the three approaches used to define diurnal periods. The distribution of differences, represented by 95% confidence intervals (CI), in night-time systolic and diastolic ABP and daytime systolic and diastolic ABP was narrowest for self-report versus actigraphy. For example, mean differences (95% CI) in night-time systolic ABP for self-report versus fixed-time was -0.53 (-6.61, +5.56) mmHg, self-report versus actigraphy was 0.91 (-3.61, +5.43) mmHg, and fixed-time versus actigraphy was 1.43 (-5.59, +8.46) mmHg. Agreement for night-time and daytime hypertension was highest for self-report versus actigraphy: kappa statistic (95% CI) = 0.91 (0.86,0.96) and 1.00 (0.98,1.00), respectively. The reproducibility of mean ABP and hypertension categories was similar using each approach. Given the high agreement with actigraphy, these data support using self-report to define diurnal periods on ABP monitoring. Further, the use of fixed-time periods may be a reasonable alternative approach.

  8. MMS two-phase nonequilibrium pressurizer

    International Nuclear Information System (INIS)

    Oh, S.J.; Sursock, J.P.

    1987-01-01

    The pressurizer of a nuclear steam supply system establishes and maintains the nuclear plant primary loop pressure within the prescribed limit. It is a vertical cylindrical vessel which provides a water reserve and a steam surge chamber to accommodate coolant density changes during operation. To adjust the pressure to a desired value, electric heaters are provided in its lower section and the spray nozzles are provided in its upper section. Also, to protect against the buildup of the excess pressure, the pressurizer has two different types of relief valves, i.e., power operated relief valve and the safety relief valve. The pressurizer model implemented to the MMS is described in detail. In particular, the handling of the nonequilibrium condition, surgeline CCFL (Counter-current Flooding Limitation), and the level tracking model are described in detail. Next, the simulation of the Shippingport pressurizer load drop test is reported

  9. Variation of energy absorption buildup factors with incident photon energy and penetration depth for some commonly used solvents

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Parjit S. [Department of Physics, Punjabi University, Patiala 147 002 (India)], E-mail: dr_parjit@hotmail.com; Singh, Tejbir [Department of Physics, Lovely Professional University, Phagwara 144 402 (India); Kaur, Paramjeet [IAS and Allied Services Training Centre, Punjabi University, Patiala 147 002 (India)

    2008-06-15

    G.P. fitting method has been used to compute energy absorption buildup factor of some commonly used solvents such as acetonitrile (C{sub 4}H{sub 3}N), butanol (C{sub 4}H{sub 9}OH), chlorobenzene (C{sub 6}H{sub 5}Cl), diethyl ether (C{sub 4}H{sub 10}O), ethanol (C{sub 2}H{sub 5}OH), methanol (CH{sub 3}OH), propanol (C{sub 3}H{sub 7}OH) and water (H{sub 2}O) for the wide energy range (0.015-15.0 MeV) up to the penetration depth of 10 mean free path. The variation of energy absorption buildup factor with chemical composition as well as incident photon energy for the selected solvents has been studied. It has been observed that the maximum value of energy absorption buildup factors shifts to the slightly higher incident photon energy with the increase in equivalent atomic number of the solvent and the solvent with least equivalent atomic number possesses the maximum value of energy absorption buildup factor.

  10. Insect Venom Immunotherapy: Analysis of the Safety and Tolerance of 3 Buildup Protocols Frequently Used in Spain.

    Science.gov (United States)

    Gutiérrez Fernández, D; Moreno-Ancillo, A; Fernández Meléndez, S; Domínguez-Noche, C; Gálvez Ruiz, P; Alfaya Arias, T; Carballada González, F; Alonso Llamazares, A; Marques Amat, L; Vega Castro, A; Antolín Amérigo, D; Cruz Granados, S; Ruiz León, B; Sánchez Morillas, L; Fernández Sánchez, J; Soriano Gomis, V; Borja Segade, J; Dalmau Duch, G; Guspi Bori, R; Miranda Páez, A

    2016-01-01

    Hymenoptera venom immunotherapy (VIT) is an effective treatment but not one devoid of risk, as both local and systemic adverse reactions may occur, especially in the initial phases. We compared the tolerance to 3 VIT buildup protocols and analyzed risk factors associated with adverse reactions during this phase. We enrolled 165 patients divided into 3 groups based on the buildup protocol used (3, 4, and 9 weeks). The severity of systemic reactions was evaluated according to the World Allergy Organization model. Results were analyzed using exploratory descriptive statistics, and variables were compared using analysis of variance. Adverse reactions were recorded in 53 patients (32%) (43 local and 10 systemic). Local reactions were immediate in 27 patients (63%) and delayed in 16 (37%). The severity of the local reaction was slight/moderate in 15 patients and severe in 13. Systemic reactions were grade 1-2. No significant association was found between the treatment modality and the onset of local or systemic adverse reactions or the type of local reaction. We only found a statistically significant association between severity of the local reaction and female gender. As for the risk factors associated with systemic reactions during the buildup phase, we found no significant differences in values depending on the protocol used or the insect responsible. The buildup protocols compared proved to be safe and did not differ significantly from one another. In the population studied, patients undergoing the 9-week schedule presented no systemic reactions. Therefore, this protocol can be considered the safest approach.

  11. Effect of Nigella sativa supplementation over a one-year period on lipid levels, blood pressure and heart rate in type-2 diabetic patients receiving oral hypoglycemic agents: nonrandomized clinical trial.

    Science.gov (United States)

    Badar, Ahmed; Kaatabi, Huda; Bamosa, Abdullah; Al-Elq, Abdulmohsen; Abou-Hozaifa, Bodour; Lebda, Fatma; Alkhadra, Akram; Al-Almaie, Sameeh

    2017-01-01

    Diabetic patients with hypertension and dyslipidemia are at a high risk of cardiovascular complications. To determine the effect of Nigella sativa supplementation on the lipid profile, mean arterial pressure, and heart rate in persons with type 2 diabetes on oral hypoglycemic agents (OHA). Single-blind, nonrandomized. Diabetes clinic of a university hospital in Saudi Arabia. Type-2 diabetic patients were recruited by purposive sampling and assigned to treatment or control at the discretion of the investigator with the patient blinded to treatment. Before the in.tervention and every 3 months thereafter until the end of the treatment period, the following parameters were measured: triglycerides (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and body mass index (BMI). Results at the baseline and each subsequent visit were compared between the two groups. Lipid and cardiovascular parameters, and BMI. Fifty-seven patients were assigned to receive N sativa 2 g daily for one year and 57 were assigned to receive an identical regimen of placebo, along with OHA. A significant decrease in HDL-C and increase in the TC/HDL-C and LDL-C/HDL-C ratios were seen in the control group. The N sativa group had a signifi.cant decline in TC, LDL-C, TC/HDL-C and LDL-C/HDL-C ratios, compared with the respective baseline data and the control group. HDL-C was significantly elevated in the N sativa group. The control group showed a significant elevation in MAP. The N sativa group had a significant reduction in SBP, DBP, MAP and HR and a significant decrease in DBP, MAP and HR as compared with the control group. N sativa supplementation improves total cholesterol, mean arterial pressure and heart rate in type 2 diabetes patients on oral hypoglycemic agents. There were 9 subjects in each group lost to follow up

  12. Extremely rare collapse and build-up of turbulence in stochastic models of transitional wall flows.

    Science.gov (United States)

    Rolland, Joran

    2018-02-01

    This paper presents a numerical and theoretical study of multistability in two stochastic models of transitional wall flows. An algorithm dedicated to the computation of rare events is adapted on these two stochastic models. The main focus is placed on a stochastic partial differential equation model proposed by Barkley. Three types of events are computed in a systematic and reproducible manner: (i) the collapse of isolated puffs and domains initially containing their steady turbulent fraction; (ii) the puff splitting; (iii) the build-up of turbulence from the laminar base flow under a noise perturbation of vanishing variance. For build-up events, an extreme realization of the vanishing variance noise pushes the state from the laminar base flow to the most probable germ of turbulence which in turn develops into a full blown puff. For collapse events, the Reynolds number and length ranges of the two regimes of collapse of laminar-turbulent pipes, independent collapse or global collapse of puffs, is determined. The mean first passage time before each event is then systematically computed as a function of the Reynolds number r and pipe length L in the laminar-turbulent coexistence range of Reynolds number. In the case of isolated puffs, the faster-than-linear growth with Reynolds number of the logarithm of mean first passage time T before collapse is separated in two. One finds that ln(T)=A_{p}r-B_{p}, with A_{p} and B_{p} positive. Moreover, A_{p} and B_{p} are affine in the spatial integral of turbulence intensity of the puff, with the same slope. In the case of pipes initially containing the steady turbulent fraction, the length L and Reynolds number r dependence of the mean first passage time T before collapse is also separated. The author finds that T≍exp[L(Ar-B)] with A and B positive. The length and Reynolds number dependence of T are then discussed in view of the large deviations theoretical approaches of the study of mean first passage times and

  13. Extremely rare collapse and build-up of turbulence in stochastic models of transitional wall flows

    Science.gov (United States)

    Rolland, Joran

    2018-02-01

    This paper presents a numerical and theoretical study of multistability in two stochastic models of transitional wall flows. An algorithm dedicated to the computation of rare events is adapted on these two stochastic models. The main focus is placed on a stochastic partial differential equation model proposed by Barkley. Three types of events are computed in a systematic and reproducible manner: (i) the collapse of isolated puffs and domains initially containing their steady turbulent fraction; (ii) the puff splitting; (iii) the build-up of turbulence from the laminar base flow under a noise perturbation of vanishing variance. For build-up events, an extreme realization of the vanishing variance noise pushes the state from the laminar base flow to the most probable germ of turbulence which in turn develops into a full blown puff. For collapse events, the Reynolds number and length ranges of the two regimes of collapse of laminar-turbulent pipes, independent collapse or global collapse of puffs, is determined. The mean first passage time before each event is then systematically computed as a function of the Reynolds number r and pipe length L in the laminar-turbulent coexistence range of Reynolds number. In the case of isolated puffs, the faster-than-linear growth with Reynolds number of the logarithm of mean first passage time T before collapse is separated in two. One finds that ln(T ) =Apr -Bp , with Ap and Bp positive. Moreover, Ap and Bp are affine in the spatial integral of turbulence intensity of the puff, with the same slope. In the case of pipes initially containing the steady turbulent fraction, the length L and Reynolds number r dependence of the mean first passage time T before collapse is also separated. The author finds that T ≍exp[L (A r -B )] with A and B positive. The length and Reynolds number dependence of T are then discussed in view of the large deviations theoretical approaches of the study of mean first passage times and multistability

  14. Impacts of traffic and rainfall characteristics on heavy metals build-up and wash-off from urban roads.

    Science.gov (United States)

    Mahbub, Parvez; Ayoko, Godwin A; Goonetilleke, Ashantha; Egodawatta, Prasanna; Kokot, Serge

    2010-12-01

    An investigation into the effects of changes in urban traffic characteristics due to rapid urbanisation and the predicted changes in rainfall characteristics due to climate change on the build-up and wash-off of heavy metals was carried out in Gold Coast, Australia. The study sites encompassed three different urban land uses. Nine heavy metals commonly associated with traffic emissions were selected. The results were interpreted using multivariate data analysis and decision making tools, such as principal component analysis (PCA), fuzzy clustering (FC), PROMETHEE, and GAIA. Initial analyses established high, low, and moderate traffic scenarios as well as low, low to moderate, moderate, high, and extreme rainfall scenarios for build-up and wash-off investigations. GAIA analyses established that moderate to high traffic scenarios could affect the build-up, while moderate to high rainfall scenarios could affect the wash-off of heavy metals under changed conditions. However, in wash-off, metal concentrations in 1-75 μm fraction were found to be independent of the changes to rainfall characteristics. In build-up, high traffic activities in commercial and industrial areas influenced the accumulation of heavy metal concentrations in particulate size range from 75 - >300 μm, whereas metal concentrations in finer size range of 300 μm can be targeted for removal of Ni, Cu, Pb, Cd, Cr, and Zn from build-up, while organic matter from 300 μm can be targeted for removal of Cd, Cr, Pb, and Ni from wash-off. Cu and Zn need to be removed as free ions from most fractions in wash-off.

  15. Genetic diversity of G1P[8] rotavirus VP7 and VP8* antigens in Finland over a 20-year period: No evidence for selection pressure by universal mass vaccination with RotaTeq® vaccine.

    Science.gov (United States)

    Hemming, Maria; Vesikari, Timo

    2013-10-01

    Two live-attenuated oral vaccines (Rotarix™ and Rotateq®) against rotavirus gastroenteritis were licensed in 2006 and have been introduced into National Immunization Programs (NIPs) of several countries. Large scale use of rotavirus vaccines might cause antigenic pressure on circulating rotavirus types or lead to selection of new rotaviruses thus decreasing vaccine efficacy. We examined the nucleotide and amino acid sequences of the surface proteins VP7 and VP4 (cleaved to VP8(*) and VP5(*)) of a total of 108 G1P[8] rotavirus strains collected over a 20-year period from 1992, including the years 2006-2009 when rotavirus vaccine (mainly Rotarix™) was available, and the years 2009-2012 after implementation of RotaTeq® vaccine into the NIP of Finland. In G1 VP7 no changes at amino acid level were observed. In VP8(*) periodical fluctuation of the sublineage over the study period was found with multiple changes both at nucleotide and amino acid levels. Most amino acid changes were in the dominant antigenic epitopes of VP8(*). A change in VP8(*) sublineage occurred between 2008 and 2009, with a temporal correlation to the use of Rotarix™ up to 30% coverage in the period. In contrast, no antigenic changes in the VP8(*) protein appeared to be correlated to the exclusive use of RotaTeq® vaccine after 2009. Nevertheless, long-term surveillance of antigenic changes in VP4 and also VP7 proteins in wild-type rotavirus strains is warranted in countries with large scale use of the currently licensed live oral rotavirus vaccines. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Uji ketahanan galur padi terhadap wereng coklat biotipe 3 melalui population build-up

    Directory of Open Access Journals (Sweden)

    Baehaki Suherlan Effendi

    2015-09-01

    Full Text Available Screening of rice lines resistance to brown planthopper (BPH through mass screening, filtering line resistance and the population build-up are essential for the release of resistant rice varieties. In addition, the stages of the endurance are important in determining the stability of resistance, as well as the type of resistant. The research was carried out in the screen house at Indonesian Center for Rice Research in 2007. The BPH used in the research was the off spring of BPH biotype 3 that had been rearing on IR42 (bph2 variety since 1994. The result of this research showed that 22.2% of 18 lines/varieties were moderately resistant to BPH biotype 3ft namely BP4130-1f-13-3-2*B, BP4188-7f-1-2-2*B, BP2870-4e- Kn-22-2-1-5*B, and Pulut Lewok. On the population build-up test, the above lines/varieties were moderately resistant to BPH biotype 3pb. The low FPLI values were found in BP4130-1f-13-3-2*B and Pulut Lewok. The highest tolerance index was found on BP4130-1f- 13-3-2*B and Pulut Lewok followed by BP2870-4e-Kn-22-2-1-5*B and BP4188-7f-1-2-2*B. Pulut Lewok has the highest antibiosis index and is not significantly different to BP4130-1f-13-3-2*B, while BP4188-7f-1-2-2*B was lowest. Although Pulut Lewok has antibiosis defense mechanism, it is not tolerant to BPH biotype 3. The BP4130-1f-13-3-2*B line have both antibiosis and tolerant to BPH biotype 3. BP4188-7f-1-2-2*B line has tolerance character, but does not have character of antibiosis to BPH biotype 3.

  17. Problem Periods

    Science.gov (United States)

    ... ovary syndrome. Read our information on PCOS for teens , and see your doctor if you think you may have PCOS. Major weight loss. Girls who have anorexia will often stop having periods. When to see ...

  18. Molecular Dynamics of Equilibrium and Pressure-Driven Transport Properties of Water through LTA-Type Zeolites

    KAUST Repository

    Turgman-Cohen, Salomon; Araque, Juan C.; Hoek, Eric M. V.; Escobedo, Fernando A.

    2013-01-01

    We consider an atomistic model to investigate the flux of water through thin Linde type A (LTA) zeolite membranes with differing surface chemistries. Using molecular dynamics, we have studied the flow of water under hydrostatic pressure through a fully hydrated LTA zeolite film (∼2.5 nm thick) capped with hydrophilic and hydrophobic moieties. Pressure drops in the 50-400 MPa range were applied across the membrane, and the flux of water was monitored for at least 15 ns of simulation time. For hydrophilic membranes, water molecules adsorb at the zeolite surface, creating a highly structured fluid layer. For hydrophobic membranes, a depletion of water molecules occurs near the water/zeolite interface. For both types of membranes, the water structure is independent of the pressure drop established in the system and the flux through the membranes is lower than that observed for the bulk zeolitic material; the latter allows an estimation of surface barrier effects to pressure-driven water transport. Mechanistically, it is observed that (i) bottlenecks form at the windows of the zeolite structure, preventing the free flow of water through the porous membrane, (ii) water molecules do not move through a cage in a single-file fashion but rather exhibit a broad range of residence times and pronounced mixing, and (iii) a periodic buildup of a pressure difference between inlet and outlet cages takes place which leads to the preferential flow of water molecules toward the low-pressure cages. © 2013 American Chemical Society.

  19. Molecular Dynamics of Equilibrium and Pressure-Driven Transport Properties of Water through LTA-Type Zeolites

    KAUST Repository

    Turgman-Cohen, Salomon

    2013-10-08

    We consider an atomistic model to investigate the flux of water through thin Linde type A (LTA) zeolite membranes with differing surface chemistries. Using molecular dynamics, we have studied the flow of water under hydrostatic pressure through a fully hydrated LTA zeolite film (∼2.5 nm thick) capped with hydrophilic and hydrophobic moieties. Pressure drops in the 50-400 MPa range were applied across the membrane, and the flux of water was monitored for at least 15 ns of simulation time. For hydrophilic membranes, water molecules adsorb at the zeolite surface, creating a highly structured fluid layer. For hydrophobic membranes, a depletion of water molecules occurs near the water/zeolite interface. For both types of membranes, the water structure is independent of the pressure drop established in the system and the flux through the membranes is lower than that observed for the bulk zeolitic material; the latter allows an estimation of surface barrier effects to pressure-driven water transport. Mechanistically, it is observed that (i) bottlenecks form at the windows of the zeolite structure, preventing the free flow of water through the porous membrane, (ii) water molecules do not move through a cage in a single-file fashion but rather exhibit a broad range of residence times and pronounced mixing, and (iii) a periodic buildup of a pressure difference between inlet and outlet cages takes place which leads to the preferential flow of water molecules toward the low-pressure cages. © 2013 American Chemical Society.

  20. Shielded button electrodes for time-resolved measurements of electron cloud buildup

    International Nuclear Information System (INIS)

    Crittenden, J.A.; Billing, M.G.; Li, Y.; Palmer, M.A.; Sikora, J.P.

    2014-01-01

    We report on the design, deployment and signal analysis for shielded button electrodes sensitive to electron cloud buildup at the Cornell Electron Storage Ring. These simple detectors, derived from a beam-position monitor electrode design, have provided detailed information on the physical processes underlying the local production and the lifetime of electron densities in the storage ring. Digitizing oscilloscopes are used to record electron fluxes incident on the vacuum chamber wall in 1024 time steps of 100 ps or more. The fine time steps provide a detailed characterization of the cloud, allowing the independent estimation of processes contributing on differing time scales and providing sensitivity to the characteristic kinetic energies of the electrons making up the cloud. By varying the spacing and population of electron and positron beam bunches, we map the time development of the various cloud production and re-absorption processes. The excellent reproducibility of the measurements also permits the measurement of long-term conditioning of vacuum chamber surfaces

  1. Comparative study of mechanical properties of direct core build-up materials

    Directory of Open Access Journals (Sweden)

    Girish Kumar

    2015-01-01

    Full Text Available Background and Objectives: The strength greatly influences the selection of core material because core must withstand forces due to mastication and para-function for many years. This study was conducted to evaluate certain mechanical properties of commonly used materials for direct core build-up, including visible light cured composite, polyacid modified composite, resin modified glass ionomer, high copper amalgam, and silver cermet cement. Materials and Methods: All the materials were manipulated according to the manufacturer′s recommendations and standard test specimens were prepared. A universal testing machine at different cross-head speed was used to determine all the four mechanical properties. Mean compressive strength, diametral tensile strength, flexural strength, and elastic modulus with standard deviations were calculated. Multiple comparisons of the materials were also done. Results: Considerable differences in compressive strength, diametral tensile strength, and flexural strength were observed. Visible light cured composite showed relatively high compressive strength, diametral tensile strength, and flexural strength compared with the other tested materials. Amalgam showed the highest value for elastic modulus. Silver cermet showed less value for all the properties except for elastic modulus. Conclusions: Strength is one of the most important criteria for selection of a core material. Stronger materials better resist deformation and fracture provide more equitable stress distribution, greater stability, and greater probability of clinical success.

  2. The Build-Up Course of Visuo-Motor and Audio-Motor Temporal Recalibration

    Directory of Open Access Journals (Sweden)

    Yoshimori Sugano

    2011-10-01

    Full Text Available The sensorimotor timing is recalibrated after a brief exposure to a delayed feedback of voluntary actions (temporal recalibration effect: TRE (Heron et al., 2009; Stetson et al., 2006; Sugano et al., 2010. We introduce a new paradigm, namely ‘synchronous tapping’ (ST which allows us to investigate how the TRE builds up during adaptation. In each experimental trial, participants were repeatedly exposed to a constant lag (∼150 ms between their voluntary action (pressing a mouse and a feedback stimulus (a visual flash / an auditory click 10 times. Immediately after that, they performed a ST task with the same stimulus as a pace signal (7 flashes / clicks. A subjective ‘no-delay condition’ (∼50 ms served as control. The TRE manifested itself as a change in the tap-stimulus asynchrony that compensated the exposed lag (eg, after lag adaptation, the tap preceded the stimulus more than in control and built up quickly (∼3–6 trials, ∼23–45 sec in both the visuo- and audio-motor domain. The audio-motor TRE was bigger and built-up faster than the visuo-motor one. To conclude, the TRE is comparable between visuo- and audio-motor domain, though they are slightly different in size and build-up rate.

  3. Kick-Off Point (KOP and End of Buildup (EOB Data Analysis in Trajectory Design

    Directory of Open Access Journals (Sweden)

    Novrianti Novrianti

    2017-06-01

    Full Text Available Well X is a development well which is directionally drilled. Directional drilling is choosen because the coordinate target of Well X is above the buffer zone. The directional track plan needs accurate survey calculation in order to make the righ track for directional drilling. There are many survey calculation in directional drilling such as tangential, underbalance, average angle, radius of curvature, and mercury method. Minimum curvature method is used in this directional track plan calculation. This method is used because it gives less error than other method.  Kick-Off Point (KOP and End of Buildup (EOB analysis is done at 200 ft, 400 ft, and 600 ft depth to determine the trajectory design and optimal inclination. The hole problem is also determined in this trajectory track design. Optimal trajectory design determined at 200 ft depth because the inclination below 35º and also already reach the target quite well at 1632.28 ft TVD and 408.16 AHD. The optimal inclination at 200 ft KOP depth because the maximum inclination is 18.87º which is below 35º. Hole problem will occur if the trajectory designed at 600 ft. The problems are stuck pipe and the casing or tubing will not able to bend.

  4. Correction of build-up factor one x-ray hvl measurement

    International Nuclear Information System (INIS)

    Yuliati, Helfi; Akhadi, Mukhlis

    2000-01-01

    Research to obtain the value build-up factor (b) on half value layers (HVL) measurement of diagnostic X-Rays using pocket dosimeter behind aluminium (AI) filter with its thickness vary from 1 to 4 mm. From the measurement it was obtained HVL value of 1.997, 2.596 and 2.718 mmAI for X-Rays of kVp : 80 Kv with 1, 2, 3 and 4 mm filter thickness respectively. HVL value significantly increase with increasing AI filter thickness. Increasing of HVL means increasing filter thickness. From the calculation it was obtained increasing b value relative to 1 mm AI filter of 18.26 and 46% for filter thickness of 2, 3 and 4 mm respectively. Experiment result shows the need of involving b value in HVL calculation of X-Rays if the filter is relatively thick. Calculation of HVL of X-Rays can be carried out with thin layers filter. Key words : x-rays, half value layer, build up factor

  5. Development of fitting methods using geometric progression formulae of gamma-ray buildup factors

    International Nuclear Information System (INIS)

    Yoshida, Yoshitaka

    2006-01-01

    The gamma ray buildup factors are represented by an approximation method to speed up calculation using the point attenuation kernel method. The fitting parameters obtained by the GP formula and Taylor's formula are compiled in ANSI/ANS 6.4.3, available without any limitation. The GP formula featured high accuracy but required a high-level fitting technique. Thus the GP formula was divided into a curved line and a part representing the base values and used to develop the a fitting method and X k fitting method. As a result, this methodology showed that (1) when the fitting ranges were identical, there was no change in standard deviation when the unit penetration depth was varied; (2) even with fitting up to 300 mfp, the average standard deviation of 26 materials was 2.9% and acceptable GP parameters were extracted; (3) when the same end points of the fitting were selected and the starting points of fitting were identical with the unit penetration depth, the deviation became smaller with increasing unit penetration depth; and (4) even with the deviation adjusted to the positive side from 0.5 mfp to 300 mfp, the average standard deviation of 26 materials was 5.6%, which was an acceptable value. However, the GP parameters obtained by this methodology cannot be used for direct interpolation using gamma ray energy or materials. (author)

  6. VVER operational experience - effect of preconditioning and primary water chemistry on radioactivity build-up

    International Nuclear Information System (INIS)

    Zmitko, M.; Kysela, J.; Dudjakova, K.; Martykan, M.; Janesik, J.; Hanus, V.; Marcinsky, P.

    2004-01-01

    The primary coolant technology approaches currently used in VVER units are reviewed and compared with those used in PWR units. Standard and modified water chemistries differing in boron-potassium control are discussed. Preparation of the VVER Primary Water Chemistry Guidelines in the Czech Republic is noted. Operational experience of some VVER units, operated in the Czech Republic and Slovakia, in the field of the primary water chemistry, and radioactivity transport and build-up are presented. In Mochovce and Temelin units, a surface preconditioning (passivation) procedure has been applied during hot functional tests. The main principles of the controlled primary water chemistry applied during the hot functional tests are reviewed and importance of the water chemistry, technological and other relevant parameters is stressed regarding to the quality of the passive layer formed on the primary system surfaces. The first operational experience obtained in the course of beginning of these units operation is presented mainly with respect to the corrosion products coolant and surface activities. Effect of the initial passivation performed during hot functional tests and the primary water chemistry on corrosion products radioactivity level and radiation situation is discussed. (author)

  7. Probability analysis of MCO over-pressurization during staging

    International Nuclear Information System (INIS)

    Pajunen, A.L.

    1997-01-01

    The purpose of this calculation is to determine the probability of Multi-Canister Overpacks (MCOs) over-pressurizing during staging at the Canister Storage Building (CSB). Pressurization of an MCO during staging is dependent upon changes to the MCO gas temperature and the build-up of reaction products during the staging period. These effects are predominantly limited by the amount of water that remains in the MCO following cold vacuum drying that is available for reaction during staging conditions. Because of the potential for increased pressure within an MCO, provisions for a filtered pressure relief valve and rupture disk have been incorporated into the MCO design. This calculation provides an estimate of the frequency that an MCO will contain enough water to pressurize beyond the limits of these design features. The results of this calculation will be used in support of further safety analyses and operational planning efforts. Under the bounding steady state CSB condition assumed for this analysis, an MCO must contain less than 1.6 kg (3.7 lbm) of water available for reaction to preclude actuation of the pressure relief valve at 100 psid. To preclude actuation of the MCO rupture disk at 150 psid, an MCO must contain less than 2.5 kg (5.5 lbm) of water available for reaction. These limits are based on the assumption that hydrogen generated by uranium-water reactions is the sole source of gas produced within the MCO and that hydrates in fuel particulate are the primary source of water available for reactions during staging conditions. The results of this analysis conclude that the probability of the hydrate water content of an MCO exceeding 1.6 kg is 0.08 and the probability that it will exceed 2.5 kg is 0.01. This implies that approximately 32 of 400 staged MCOs may experience pressurization to the point where the pressure relief valve actuates. In the event that an MCO pressure relief valve fails to open, the probability is 1 in 100 that the MCO would experience

  8. SU-E-T-59: Calculations of Collimator Scatter Factors (Sc) with and Without Custom-Made Build-Up Caps for CyberKnife

    Energy Technology Data Exchange (ETDEWEB)

    Wokoma, S; Yoon, J; Jung, J [East Carolina University, Greenville, NC (United States); Lee, S [Rhode Island Hospital / Warren Alpert Medical, Providence, RI (United States)

    2014-06-01

    Purpose: To investigate the impact of custom-made build-up caps for a diode detector in robotic radiosurgery radiation fields with variable collimator (IRIS) for collimator scatter factor (Sc) calculation. Methods: An acrylic cap was custom-made to fit our SFD (IBA Dosimetry, Germany) diode detector. The cap has thickness of 5 cm, corresponding to a depth beyond electron contamination. IAEA phase space data was used for beam modeling and DOSRZnrc code was used to model the detector. The detector was positioned at 80 cm source-to-detector distance. Calculations were performed with the SFD, with and without the build-up cap, for clinical IRIS settings ranging from 7.5 to 60 mm. Results: The collimator scatter factors were calculated with and without 5 cm build-up cap. They were agreed within 3% difference except 15 mm cone. The Sc factor for 15 mm cone without buildup was 13.2% lower than that with buildup. Conclusion: Sc data is a critical component in advanced algorithms for treatment planning in order to calculate the dose accurately. After incorporating build-up cap, we discovered differences of up to 13.2 % in Sc factors in the SFD detector, when compared against in-air measurements without build-up caps.

  9. Humidity Build-Up in a Typical Electronic Enclosure Exposed to Cycling Conditions and Effect on Corrosion Reliability

    DEFF Research Database (Denmark)

    Conseil, Helene; Gudla, Visweswara Chakravarthy; Jellesen, Morten Stendahl

    2016-01-01

    The design of electronic device enclosures plays a major role in determining the humidity build-up inside the device as a response to the varying external humidity. Therefore, the corrosion reliability of electronic devices has direct connection to the enclosure design. This paper describes......, thermal mass, and port/opening size. The effect of the internal humidity build-up on corrosion reliability has been evaluated by measuring the leakage current (LC) on interdigitated test comb patterns, which are precontaminated with sodium chloride and placed inside the enclosure. The results showed...... that the exposure to cycling temperature causes significant change of internal water vapor concentration. The maximum value of humidity reached was a function of the opening size and the presence of thermal mass inside the enclosure. A pumping effect was observed due to cycling temperature, and the increase...

  10. A study of energy and effective atomic number dependence of the exposure build-up factors in biological samples

    International Nuclear Information System (INIS)

    Sidhu, G.S.; Singh, P.S.; Mudahar, G.S.

    2000-01-01

    A theoretical method is presented to determine the gamma-radiation build-up factors in various biological materials. The gamma energy range is 0.015-15.0 MeV, with penetration depths up to 40 mean free paths considered. The dependence of the exposure build-up factor on incident photon energy and the effective atomic number (Z eff ) has also been assessed. In a practical analysis of dose burden to gamma-irradiated biological materials, the sophistication of Monte Carlo computer techniques would be applied, with associated detailed modelling. However, a feature of the theoretical method presented is its ability to make the consequences of the physics of the scattering process in biological materials more transparent. In addition, it can be quickly employed to give a first-pass dose estimate prior to a more detailed computer study. (author)

  11. Measurement of exposure buildup factors: The influence of scattered photons on gamma-ray attenuation coefficients

    Science.gov (United States)

    Mann, Kulwinder Singh

    2018-01-01

    Scattered photon's influence on measured values of attenuation coefficients (μm, cm2g-1) for six low-Z (effective atomic number) building materials, at three photon energies has been estimated. Narrow-beam transmission geometry has been used for the measurements. Samples of commonly used engineering materials (Cements, Clay, Lime-Stone, Plaster of Paris) have been selected for the present study. Standard radioactive sources Cs137 and Co60 have been used for obtaining γ-ray energies 661.66, 1173.24 and 1332.50 keV. The optical thickness (OT) of 0.5 mfp (mean free path) has been found the optimum optical thickness (OOT) for μm-measurement in the selected energy range (661.66-1332.50 keV). The aim of this investigation is to provide neglected information regarding subsistence of scattered photons in narrow beam geometry measurements for low-Z materials. The measurements have been performed for a wide range of sample-thickness (2-26 cm) such that their OT varies between 0.2-3.5 mfp in selected energy range. A computer program (GRIC2-toolkit) has been used for various theoretical computations required in this investigation. It has been concluded that in selected energy-range, good accuracy in μm-measurement of low-Z materials can be achieved by keeping their sample's OT below 0.5 mfp. The exposure buildup factors have been measured with the help of mathematical-model developed in this investigation.

  12. Reducing the rate of carbon dioxide buildup with biomass fuel under climate change

    International Nuclear Information System (INIS)

    Peart, R.; Curry, R.; Jones, J.; Boote, K.; Allen, L.

    1993-01-01

    The authors have been working for several years on estimating, through crop simulation and crop growth chamber experiments, the changes in yield and in irrigation demand which would be brought about by a doubling of atmospheric greenhouse gases, given the results of three General Circulation Models (GCM) that simulate the climate change that would be expected. They are now beginning to study the impact this might have in relation to biomass fuels. An important question is the effect of the changed climate on crop production, would the increased carbon dioxide concentration outweigh the negative climate change effects on crop yields? Results are quite variable due to different climate change effects at different locations and the differences in historical weather and in soils in different locations. However, on balance, climate change would result in reduced yields of the crops we studied, soybean, maize and peanut. However, US production of these crops could be maintained or increased by the use of irrigation on more acres. Irrigated crops, in general, would have increased yields under climate change because of the increased photosynthetic efficiency with higher carbon dioxide levels. Results on net remediation of carbon dioxide buildup by the use of biomass fuel rather than fossil fuel are not completed, but previous work has shown that Midwest non-irrigated maize production provides much more equivalent biomass energy than is required for its production. The studies with soybean show a ratio of equivalent energy output in the seed to energy used in producing the crop ranging from 4 to almost 9 under climate change

  13. Venom Immunotherapy in High-Risk Patients: The Advantage of the Rush Build-Up Protocol.

    Science.gov (United States)

    Rosman, Yossi; Confino-Cohen, Ronit; Goldberg, Arnon

    2017-01-01

    Venom immunotherapy (VIT) is considered to be the gold standard treatment for patients with hymenoptera venom allergy. This treatment induces systemic reactions (SR) in a significant number of patients. To evaluate the outcome of VIT in patients with known risk factors for VIT-induced SR and to compare rush VIT (RVIT) and conventional VIT (CVIT). All of the patients who received VIT and had at least one of the following risk factors were included: current cardiovascular disease, uncontrolled asthma, high basal serum tryptase, current treatment with β-blockers or angiotensin-converting enzyme inhibitors, and age >70 or bee venom. Thirty-five (54.7%) patients underwent RVIT and 29 CVIT. The incidence of patients who developed SR during the build-up phase was similar for RVIT and CVIT (25.7 and 27.5%, respectively; p = 1). However, the incidence of SR per injection was significantly higher in CVIT than in RVIT (5.6 and 2.75%, respectively; p = 0.01). Most reactions (79.1%) were mild, limited to the skin. Most of the patients (92.1%) reached the full maintenance dose of 100 μg. This dose was reached by a significantly larger number of patients receiving RVIT compared to CVIT (100 and 82.7%, respectively; p = 0.01). None of the patients experienced exacerbation of their concurrent chronic disease during VIT. VIT can be performed safely and efficiently in patients with risk factors for immunotherapy. In these patients RVIT appears to be safer and more efficient than CVIT. © 2017 S. Karger AG, Basel.

  14. Clinical comparison of various esthetic restorative options for coronal build-up of primary anterior teeth

    Directory of Open Access Journals (Sweden)

    Himanshu Duhan

    2015-01-01

    Full Text Available Background: This study was designed to compare the clinical performance of composite, strip crowns, biological restoration, and composite with stainless steel band when used for the coronal build-up of anterior teeth. Materials and Methods: A total of 20 patients aged 3-6 years presenting with mutilated primary anterior teeth due to caries or trauma were selected for the study using randomized simple sampling. A total of 52 primary anterior teeth were randomly divided into four equal groups having 13 teeth in each group. Teeth in Group I were restored with composite, in Group II with strip crowns, in Group III with biologic restoration and with stainless steel band reinforced composite in group IV. The restorations were evaluated for color match, retention, surface texture, and anatomic form according to Ryge′s Direct (US Public Health Service evaluation criteria at baseline (immediate postoperative, after 48 h, 3, 6, and 9 months. The data obtained were statistically analyzed using Chi-square test, and level of significance, that is, P value was determined. Results: At baseline, none of the groups showed any color changes. Other than Group III all other groups showed highly significant changes (P 0.05. Deterioration in surface texture was exhibited maximum by restorations in Group IV followed by Group I at 3 months. Whereas, no surface changes were seen in Group II and III. Only Group I and IV showed discontinuity in anatomic form after 3 months. After 6 months, except in Group II, discontinuity in anatomic form was observed in all the groups. Discontinuity in anatomic form was seen in all the 4 groups after 9 months although the difference was not significant (P > 0.05. Conclusion: Biological restoration was found to be most satisfying esthetically owing to color compatibility with the patient′s tooth. Thus, it has a great potential to be used as esthetic restorative option in primary anteriors.

  15. Simulations of the electron cloud buildup and its influence on the microwave transmission measurement

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Oliver Sebastian, E-mail: o.haas@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Boine-Frankenheim, Oliver [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Schlossgartenstraße 8, 64289 Darmstadt (Germany); Petrov, Fedor [Technische Universität Darmstadt, Institut für Theorie Elektromagnetischer Felder, Schlossgartenstraße 8, 64289 Darmstadt (Germany)

    2013-11-21

    An electron cloud density in an accelerator can be measured using the Microwave Transmission (MWT) method. The aim of our study is to evaluate the influence of a realistic, nonuniform electron cloud on the MWT. We conduct electron cloud buildup simulations for beam pipe geometries and bunch parameters resembling roughly the conditions in the CERN SPS. For different microwave waveguide modes the phase shift induced by a known electron cloud density is obtained from three different approaches: 3D Particle-In-Cell (PIC) simulation of the electron response, a 2D eigenvalue solver for waveguide modes assuming a dielectric response function for cold electrons, a perturbative method assuming a sufficiently smooth density profile. While several electron cloud parameters, such as temperature, result in minor errors in the determined density, the transversely inhomogeneous density can introduce a large error in the measured electron density. We show that the perturbative approach is sufficient to describe the phase shift under realistic electron cloud conditions. Depending on the geometry of the beam pipe, the external magnetic field configuration and the used waveguide mode, the electron cloud density can be concentrated at the beam pipe or near the beam pipe center, leading to a severe over- or underestimation of the electron density. -- Author-Highlights: •Electron cloud distributions are very inhomogeneous, especially in dipoles. •These inhomogeneities affect the microwave transmission measurement results. •Electron density might be over- or underestimated, depending on setup. •This can be quantified with several models, e.g. a perturbative approach.

  16. Effect of curing mode on the hardness of dual-cured composite resin core build-up materials

    Directory of Open Access Journals (Sweden)

    César Augusto Galvão Arrais

    2010-06-01

    Full Text Available This study evaluated the Knoop Hardness (KHN values of two dual-cured composite resin core build-up materials and one resin cement exposed to different curing conditions. Two dual-cured core build-up composite resins (LuxaCore®-Dual, DMG; and FluoroCore®2, Dentsply Caulk, and one dual-cured resin cement (Rely X ARC, 3M ESPE were used in the present study. The composite materials were placed into a cylindrical matrix (2 mm in height and 3 mm in diameter, and the specimens thus produced were either light-activated for 40 s (Optilux 501, Demetron Kerr or were allowed to self-cure for 10 min in the dark (n = 5. All specimens were then stored in humidity at 37°C for 24 h in the dark and were subjected to KHN analysis. The results were submitted to 2-way ANOVA and Tukey's post-hoc test at a pre-set alpha of 5%. All the light-activated groups exhibited higher KHN values than the self-cured ones (p = 0.00001, regardless of product. Among the self-cured groups, both composite resin core build-up materials showed higher KHN values than the dual-cured resin cement (p = 0.00001. LuxaCore®-Dual exhibited higher KHN values than FluoroCore®2 (p = 0.00001 when they were allowed to self-cure, while no significant differences in KHN values were observed among the light-activated products. The results suggest that dual-cured composite resin core build-up materials may be more reliable than dual-cured resin cements when curing light is not available.

  17. Source term evaluation model for high-level radioactive waste repository with decay chain build-up.

    Science.gov (United States)

    Chopra, Manish; Sunny, Faby; Oza, R B

    2016-09-18

    A source term model based on two-component leach flux concept is developed for a high-level radioactive waste repository. The long-lived radionuclides associated with high-level waste may give rise to the build-up of activity because of radioactive decay chains. The ingrowths of progeny are incorporated in the model using Bateman decay chain build-up equations. The model is applied to different radionuclides present in the high-level radioactive waste, which form a part of decay chains (4n to 4n + 3 series), and the activity of the parent and daughter radionuclides leaching out of the waste matrix is estimated. Two cases are considered: one when only parent is present initially in the waste and another where daughters are also initially present in the waste matrix. The incorporation of in situ production of daughter radionuclides in the source is important to carry out realistic estimates. It is shown that the inclusion of decay chain build-up is essential to avoid underestimation of the radiological impact assessment of the repository. The model can be a useful tool for evaluating the source term of the radionuclide transport models used for the radiological impact assessment of high-level radioactive waste repositories.

  18. Urban nonpoint source pollution buildup and washoff models for simulating storm runoff quality in the Los Angeles County

    International Nuclear Information System (INIS)

    Wang Long; Wei Jiahua; Huang Yuefei; Wang Guangqian; Maqsood, Imran

    2011-01-01

    Many urban nonpoint source pollution models utilize pollutant buildup and washoff functions to simulate storm runoff quality of urban catchments. In this paper, two urban pollutant washoff load models are derived using pollutant buildup and washoff functions. The first model assumes that there is no residual pollutant after a storm event while the second one assumes that there is always residual pollutant after each storm event. The developed models are calibrated and verified with observed data from an urban catchment in the Los Angeles County. The application results show that the developed model with consideration of residual pollutant is more capable of simulating nonpoint source pollution from urban storm runoff than that without consideration of residual pollutant. For the study area, residual pollutant should be considered in pollutant buildup and washoff functions for simulating urban nonpoint source pollution when the total runoff volume is less than 30 mm. - Highlights: → An improved urban NPS model was developed. → It performs well in areas where storm events have great temporal variation. → Threshold of total runoff volume for ignoring residual pollutant was determined. - An improved urban NPS model was developed. Threshold of total runoff volume for ignoring residual pollutant was determined.

  19. The effect of different initial densities of nematode (Meloidogyne javanica) on the build-up of Pasteuria penetrans population.

    Science.gov (United States)

    Darban, Daim Ali; Pathan, Mumtaz Ali; Bhatti, Abdul Ghaffar; Maitelo, Sultan Ahmed

    2005-02-01

    Pasteuria penetrans will build-up faster where there is a high initial nematode density and can suppress root-knot nematode populations in the roots of tomato plants. The effect of different initial densities of nematode (Meloidogyne javanica) (150, 750, 1500, 3000) and P. penetrans infected females (F1, F3) densities (F0=control and AC=absolute control without nematode or P. penetrans inoculum) on the build-up of Pasteuria population was investigated over four crop cycles. Two major points of interest were highlighted. First, that within a confined soil volume, densities of P. penetrans can increase >100 times within 2 or 3 crop cycles. Second, from a relatively small amount of spore inoculum, infection of the host is very high. There were more infected females in the higher P. penetrans doses. The root growth data confirms the greater number of females in the controls particularly at the higher inoculum densities in the third and fourth crops. P. penetrans generally caused the fresh root weights to be higher than those in the control. P. penetrans has shown greater reduction of egg masses per plant at most densities. The effects of different initial densities of M. javanica and P. penetrans on the development of the pest and parasite populations were monitored. And no attempt was made to return the P. penetrans spores to the pots after each crop so the build-up in actual numbers of infected females and spores under natural conditions may be underestimated.

  20. Forced-air warming design: evaluation of intake filtration, internal microbial buildup, and airborne-contamination emissions.

    Science.gov (United States)

    Reed, Mike; Kimberger, Oliver; McGovern, Paul D; Albrecht, Mark C

    2013-08-01

    Forced-air warming devices are effective for the prevention of surgical hypothermia. However, these devices intake nonsterile floor-level air, and it is unknown whether they have adequate filtration measures to prevent the internal buildup or emission of microbial contaminants. We rated the intake filtration efficiency of a popular current-generation forced-air warming device (Bair Hugger model 750, Arizant Healthcare) using a monodisperse sodium chloride aerosol in the laboratory. We further sampled 23 forced-air warming devices (same model) in daily hospital use for internal microbial buildup and airborne-contamination emissions via swabbing and particle counting. Laboratory testing found the intake filter to be 63.8% efficient. Swabbing detected microorganisms within 100% of the forced-air warming blowers sampled, with isolates of coagulase-negative staphylococci, mold, and micrococci identified. Particle counting showed 96% of forced-air warming blowers to be emitting significant levels of internally generated airborne contaminants out of the hose end. These findings highlight the need for upgraded intake filtration, preferably high-efficiency particulate air filtration (99.97% efficient), on current-generation forced-air warming devices to reduce contamination buildup and emission risks.

  1. The effect of build-up cap materials on the response of an ionization chamber to 60Co gamma rays

    International Nuclear Information System (INIS)

    Rocha, M.P.O.; Almeida, C.E. de

    1993-01-01

    Knowledge of the effect of wall and build-up cap materials on ionization chamber response is necessary to determine absorbed dose in a medium using a calibration factor based on exposure or kerma in air. Attenuation and scattering effects of 60 Co gamma rays in the ionization chamber wall and build-up cap, as well as their non-equivalence to air, were studied with an OFS ionization chamber (Delrin wall) and a set of build-up caps specially built for this purpose. Results for a specific material were plotted as functions of wall and cap total thickness, extrapolated to zero wall thickness, then corrected for mean centre of electron production in the wall (= 0.136 g cm -2 ). Correction factors for a specific thickness were analysed in relation to cap material, and to relative responses compared with values calculated by using AAPM, SEFM and IAEA formalisms for cap effects. A Monte Carlo calculation was performed to compare the experimental and theoretical values. Calculations showed an agreement within 0.1% with experimental values and a wall effect of approximately 1.6%. (Author)

  2. A comprehensive study of the energy absorption and exposure buildup factors of different bricks for gamma-rays shielding

    Directory of Open Access Journals (Sweden)

    M.I. Sayyed

    Full Text Available The present investigation has been performed on different bricks for the purpose of gamma-ray shielding. The values of the mass attenuation coefficient (µ/ρ, energy absorption buildup factor (EABF and exposure buildup factor (EBF were determined and utilized to assess the shielding effectiveness of the bricks under investigation. The mass attenuation coefficients of the selected bricks were calculated theoretically using WinXcom program and compared with MCNPX code. Good agreement between WinXcom and MCNPX results was observed. Furthermore, the EABF and EBF have been discussed as functions of the incident photon energy and penetration depth. It has been found that the EABF and EBF values are very large in the intermediate energy region. The steel slag showed good shielding properties, consequently, this brick is eco-friendly and feasible compared with other types of bricks used for construction. The results in this work should be useful in the construction of effectual shielding against hazardous gamma-rays. Keywords: Brick, Mass attenuation coefficient, Buildup factor, G-P fitting, Radiation shielding

  3. Evaluation of Geometric Progression (GP Buildup Factors using MCNP Codes (MCNP6.1 and MCNP5-1.60

    Directory of Open Access Journals (Sweden)

    Kim Kyung-O

    2016-01-01

    Full Text Available The gamma-ray buildup factors of three-dimensional point kernel code (QAD-CGGP are re-evaluated by using MCNP codes (MCNP6.1 and MCNPX5-1.60 and ENDF/B-VI.8 photoatomic data, which cover an energy range of 0.015–15 MeV and an iron thickness of 0.5–40 Mean Free Path (MFP. These new data are fitted to the Geometric Progression (GP fitting function and are then compared with ANS standard data equipped with QAD-CGGP. In addition, a simple benchmark calculation was performed to compare the QAD-CGGP results applied with new and existing buildup factors based on the MCNP codes. In the case of the buildup factors of low-energy gamma-rays, new data are evaluated to be about 5% higher than the existing data. In other cases, these new data present a similar trend based on the specific penetration depth, while existing data continuously increase beyond that depth. In a simple benchmark, the calculations using the existing data were slightly underestimated compared to the reference data at a deep penetration depth. On the other hand, the calculations with new data were stabilized with an increasing penetration depth, despite a slight overestimation at a shallow penetration depth.

  4. A One-Dimensional Particle-in-Cell Model of Plasma Build-Up in Vacuum Arcs

    CERN Document Server

    Timko, H; Kovermann, J; Taborelli, M; Nordlund, K; Descoeudres, A; Schneider, R; Calatroni, S; Matyash, K; Wuensch, W; Hansen, A; Grudiev, A

    2011-01-01

    Understanding the mechanism of plasma build-up in vacuum arcs is essential in many fields of physics. A one-dimensional particle-in-cell computer simulation model is presented, which models the plasma developing from a field emitter tip under electrical breakdown conditions, taking into account the relevant physical phenomena. As a starting point, only an external electric field and an initial enhancement factor of the tip are assumed. General requirements for plasma formation have been identified and formulated in terms of the initial local field and a critical neutral density. The dependence of plasma build-up on tip melting current, the evaporation rate of neutrals and external circuit time constant has been investigated for copper and simulations imply that arcing involves melting currents around 0.5-1 A/mu m(2),evaporation of neutrals to electron field emission ratios in the regime 0.01 - 0.05, plasma build-up timescales in the order of similar to 1 - 10 ns and two different regimes depending on initial ...

  5. Calculation of Buildup Factor for Gamma-ray Exposure in Two Layered Shields Made of Water and Lead

    International Nuclear Information System (INIS)

    Al-Saadi, A.H.

    2012-01-01

    The buildup factor for gamma ray exposure is most useful in calculations for biological protective shields.The buildup factors for gamma ray exposure were calculated in tow layered shields consist of water-lead and lead-water up to optical Thickness 20 mean free path (mfp) at gamma ray energies 1, 2 and 6MeV by using kalos's formula.The program has been designed to work at any atomic number of the attenuating medium, photon energy, slab thickness and and the arrangement of materials.The results obtained in this search leading to the buildup factor for gamma ray exposure at energies (1and2MeV) in lead-water were higher than the reverse case,while at energy 6 MeV the effect was opposite.The calculated data were parameterized by an empirical formula as a function of optical thickness of tow materials.The results obtained were in reasonable agreement with a previous work

  6. Holocene beach buildup and coastal aeolian sand incursions off the Nile littoral cell

    Science.gov (United States)

    Roskin, Joel; Sivan, Dorit; Shtienberg, Gilad; Porat, Naomi; Bookman, Revital

    2017-04-01

    Israel's coastal plain is abundant with sand originating from the Nile littoral cell. The inland windblown loose sand has formed 3-6 km wide lobe-like sand and dune fields currently comprised of foredunes, linear and northeasterly facing transverse and parabolic dunes that are currently stabilized by vegetation. This study reviews the architecture and history of the these dune fields aiming to: (a) Date the timings of beach accretion, and sand and dune incursions. (b) Discriminate between natural and human-induced forcing factors of sand mobilization and stabilization in time and space. (c) Present a model of the dunescape development. (d) Assess scenarios of sand transport in the future charcaterized by intense human impact and climate change. Luminescence ages, radiocarbon dates and relative ages from previously published geological and archaeological reports, historical texts, together with new optically stimulated luminescence (OSL) ages and stratigraphic and sedimentological data are analyzed. The deposition, mobilizations and preservation of the sand bodies, initially induced by the decline in sea level rise at 6-4 ka, were later controlled by historic land-use intensity and modern land-use/negligence practices. At 6 ka, beach sand buildup rapidly started. Where aeolianite ridges bordered the coast, pulses of sand with biogenic carbonate grains unconformably draped the ridges and rapidly consolidated into a distinct sandy calcarenite unit. Further east, sand sheets and low dunes partly pedogenized following their incursion, but did not cement. The water retention capacities of the sand sheets enabled the establishment of a sand-stabilizing vegetation cover that probably became an attractive environment for fuel and grazing. The growing Hellenistic-Roman-Byzantine ( 2.4-1.3 ka) populations probably led to increased consumption and massive destruction of sand stabilizing vegetation, enabling sand erodibility and mobilization during winter storms. The sand

  7. Investigation of human teeth with respect to the photon interaction, energy absorption and buildup factor

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.co [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey); Topcuoglu, Sinan [Faculty of Dentistry, Department of Endodontic, Ataturk University, 25240 Erzurum (Turkey)

    2011-05-15

    The effective atomic numbers and electron densities of human teeth have been calculated for total photon interaction (Z{sub PI{sub e{sub f{sub f}}}},Ne{sub PI{sub e{sub f{sub f}}}}) and photon energy absorption (Z{sub PEA{sub e{sub f{sub f}}}},Z{sub RW{sub e{sub f{sub f}}}}Ne{sub PEA{sub e{sub f{sub f}}}}) in the energy region 1 keV-20 MeV. Besides, the energy absorption (EABF) and exposure (EBF) buildup factors have been calculated for these samples by using the geometric progression fitting approximation in the energy region 0.015-15 MeV up to 40 mfp (mean free path). Wherever possible the results were compared with experiment. Effective atomic numbers (Z{sub PI{sub e{sub f{sub f}}}}) of human teeth were calculated using different methods. Discrepancies were noted in Z{sub PI{sub e{sub f{sub f}}}} between the direct and interpolation methods in the low and high energy regions where absorption processes dominate while good agreement was observed in intermediate energy region where Compton scattering dominates. Significant variations up to 22% were observed between Z{sub PI{sub e{sub f{sub f}}}} and Z{sub PEA{sub e{sub f{sub f}}}} in the energy region 30-150 keV which is the used energy range in dental cone beam computed tomography (CBCT) X-ray machines. The Z{sub eff} values of human teeth were found to relatively vary within 1% if different laser treatments are applied. In this variation, the Er:YAG laser treated samples were found to be less effected than Nd:YAG laser treated ones when compared with control group. Relative differences between EABF and EBF were found to be significantly high in the energy region 60 keV-1 MeV even though they have similar variations with respect to the different parameters viz. photon energy, penetration depth.

  8. Aphanitic buildup from the onset of the Mulde Event (Homerian, middle Silurian at Whitman's Hill, Herefordshire, UK: ultrastructural insights into proposed microbial fabrics

    Directory of Open Access Journals (Sweden)

    Jan-Filip Päßler

    2014-12-01

    Full Text Available A microbial origin has been proposed for matrix-supported, low-diversity buildups reported from different palaeocontinents during the onset of the Mulde positive carbon isotope excursion. We have investigated a small aphanitic buildup from the Lower Quarried Limestone Member of the Much Wenlock Limestone Formation, exposed at Whitman's Hill (Herefordshire, corresponding to the central part of the Midland Platform (UK. Up to 50% of the rock volume in this buildup consists of mottled micrite. The SEM studies revealed that the micrite is largely detrital and does not show features characteristic of calcareous cyanobacteria or leiolites. The aphanitic character of the buildup is suggested to be controlled by the depositional rate, and the widespread occurrence of matrix-supported reefs in this interval to be driven by a mid-Homerian rapid eustatic transgression.

  9. Three-Step Buildup of the 17 March 2015 Storm Ring Current: Implication for the Cause of the Unexpected Storm Intensification

    Science.gov (United States)

    Keika, Kunihiro; Seki, Kanako; Nosé, Masahito; Miyoshi, Yoshizumi; Lanzerotti, Louis J.; Mitchell, Donald G.; Gkioulidou, Matina; Manweiler, Jerry W.

    2018-01-01

    We examine the spatiotemporal variations of the energy density and the energy spectral evolution of energetic ions in the inner magnetosphere during the main phase of the 17 March 2015 storm, using data from the RBSPICE and EMFISIS instruments onboard Van Allen Probes. The storm developed in response to two southward IMF intervals separated by about 3 h. In contrast to two steps seen in the Dst/SYM-H index, the ring current ion population evolved in three steps: the first subphase was apparently caused by the earlier southward IMF, and the subsequent subphases occurred during the later southward IMF period. Ion energy ranges that contribute to the ring current differed between the three subphases. We suggest that the spectral evolution resulted from the penetration of different plasma sheet populations. The ring current buildup during the first subphase was caused by the penetration of a relatively low-energy population that had existed in the plasma sheet during a prolonged prestorm northward IMF interval. The deeper penetration of the lower-energy population was responsible for the second subphase. The third subphase, where the storm was unexpectedly intensified to a Dst/SYM-H level of population. We attribute the hot, dense population to the entry of hot, dense solar wind into the plasma sheet and/or ion heating/acceleration in the near-Earth plasma sheet associated with magnetotail activity such as reconnection and dipolarization.

  10. Interpretation of changes in diffusive and non-diffusive transport in the edge plasma during pedestal buildup following a low-high transition in DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Stacey, W. M.; Sayer, M.-H.; Floyd, J.-P. [Georgia Tech, Atlanta, Georgia 30332 (United States); Groebner, R. J. [General Atomics, San Diego, California 92186 (United States)

    2013-01-15

    The evolution of diffusive and non-diffusive transport during pedestal buildup following a low-high (L-H) transition has been interpreted from a particle-momentum-energy balance analysis of the measured density, temperature, and rotation velocity profiles in the plasma edge (0.82<{rho}<1.0) of a DIII-D [Luxon, Nucl. Fusion 42, 614 (2002)] discharge. In the discharge examined, there was an edge-localized-mode-free period of more than 600 ms following the L-H transition, and the majority of edge pedestal development occurred within the first 100 ms following the L-H transition. There appears to be a spatio-temporal correlation among the measured toroidal and poloidal rotation, the formation of a negative well in the measured radial electric field, the creation of a large inward particle pinch, the calculated intrinsic rotation due to ion orbit loss, and the measured formation of steep gradients in density and temperature in the outer region ({rho}>0.95) of the edge pedestal.

  11. The effect of electron collimator leaf shape on the build-up dose in narrow electron MLC fields

    International Nuclear Information System (INIS)

    Vatanen, T; Vaeaenaenen, A; Lahtinen, T; Traneus, E

    2009-01-01

    Previously, we have found that the build-up dose from abutting narrow electron beams formed with unfocussed electron multi-leaf collimator (eMLC) steal leaves was higher than with the respective open field. To investigate more closely the effect of leaf material and shape on dose in the build-up region, straight, round (radius 1.5 cm) and leaf ends with a different front face angle of α (leaf front face pointing towards the beam axis at an angle of 90 - α) made of steel, brass and tungsten were modelled using the BEAMnrc code. Based on a treatment head simulation of a Varian 2100 C/D linac, depth-dose curves and profiles in water were calculated for narrow 6, 12 and 20 MeV eMLC beams (width 1.0 cm, length 10 cm) at source-to-surface distances (SSD) of 102 and 105 cm. The effects of leaf material and front face angle were evaluated based on electron fluence, angle and energy spectra. With a leaf front face angle of 15 deg., the dose in the build-up region of the 6 MeV field varied between 91 and 100%, while for straight and round leaf shapes the dose varied between 89 and 100%. The variation was between 94 and 100% for 12 and 20 MeV. For abutting narrow 6 MeV fields with total field size 5 x 10 cm 2 , the build-up doses at 5 mm depth for the face angle 15 deg. and straight and round leaf shapes were 96% and 86% (SSD 102 cm) and 89% and 85% (SSD 105 cm). With higher energies, the effect of eMLC leaf shape on dose at 5 mm was slight (3-4% units with 12 MeV) and marginal with 20 MeV. The fluence, energy and angle spectra for total and leaf scattered electrons were practically the same for different leaf materials with 6 MeV. With high energies, the spectra for tungsten were more peaked due to lower leaf transmission. Compared with straight leaf ends, the face angle of 15 deg. and round leaf ends led to a 1 mm (for 6 MeV) and between 1 and 5 mm (12 and 20 MeV at a SSD of 105 cm) decrease of therapeutic range and increase of the field size, respectively. However

  12. Activity build-up on the circulation loops of boiling water reactors: Basics for modelling of transport and deposition processes

    International Nuclear Information System (INIS)

    Covelli, B.; Alder, H.P.

    1988-03-01

    In the past 20 years the radiation field of nuclear power plant loops outside the core zone was the object of investigations in many countries. In this context test loops were built and basic research done. At our Institute PSI the installation of a LWR-contamination loop is planned for this year. This experimental loop has the purpose to investigate the complex phenomena of activity deposition from the primary fluid of reactor plants and to formulate analytical models. From the literature the following conclusions can be drawn: The principal correlations of the activity build-up outside the core are known. The plant specific single phenomena as corrosion, crud-transport, activation and deposit of cobalt in the oxide layer are complex and only partially understood. The operational experience of particular plants with low contaminated loops (BWR-recirculation loops) show that in principle the problem is manageable. The reduction of the activity build-up in older plants necessitates a combination of measures to modify the crud balance in the primary circuit. In parallel to the experimental work several simulation models in the form of computer programs were developed. These models have the common feature that they are based on mass balances, in which the exchange of materials and the sedimentation processes are described by global empirical transport coefficients. These models yield satisfactory results and allow parameter studies; the application however is restricted to the particular installation. All programs lack models that describe the thermodynamic and hydrodynamic mechanisms on the surface of deposition layers. Analytical investigations on fouling of process equipment led to models that are also applicable to the activity build-up in reactor loops. Therefore it seems appropriate to combine the nuclear simulation models with the fundamental equations for deposition. 10 refs., 18 figs., 3 tabs

  13. Ultrafiltration of protein solutions; the role of protein association in rejection and osmotic pressure

    NARCIS (Netherlands)

    van den Berg, G.B.; Hanemaaijer, J.H.; Smolders, C.A.

    1987-01-01

    The monomer-dimer equilibrium of the protein β-lactoglobulin under neutral conditions appears to influence the rejection and the osmotic pressure build-up, both phenomena closely related to ultrafiltration. Rejection measurements indicate different rejections for the β-lactoglobulin monomers and

  14. Understanding the build-up of supermassive black holes and galaxies

    Science.gov (United States)

    Carrera, Francisco; Ueda, Yoshihiro; Georgakakis, Antonis

    2016-07-01

    . The excellent survey capabilities of Athena/WFI (effective area, angular resolution, field of view) will allow to measure the incidence of feedback in the shape of warm absorbers and Ultra Fast Outflows among the general population of AGN, as well as to complete the census of black hole growth by detecting and characterising significant samples of the most heavily obscured (including Compton thick) AGN, to redshifts z~3-4. The outstanding spectral throughput and resolution of Athena/X-IFU will permit measuring the energetics of those outflows to assess their influence on their host galaxies. The demographics of the heavily obscured and outflowing populations relative to their hosts are fundamental for understanding how major black hole growth events relate to the build-up of galaxies.

  15. Probing the Build-Up of Quiescent Galaxies at z>3

    Science.gov (United States)

    Finkelstein, Steven

    We propose to perform the most robust investigation to date into the evolution of massive quiescent and star-forming galaxies at z > 3, at a time when the universe was less than two billion years old. The build-up of quiescent galaxies in particular is poorly understood, primarily due to large Poisson and cosmic variance issues that have plagued previous studies that probed small volumes, leading to a disagreement on the quiescent fraction by a factor of >3 in the literature. Our proposed work is only now possible due to a new legacy survey led by our team: the Spitzer-HETDEX Exploratory Large Area Survey (SHELA), which is imaging a 23 deg^2 area of the sky at optical, and near, mid and far-infrared, and X-ray wavelengths. In particular, the wide area coverage of the Spitzer/IRAC data allows us to be sensitive to massive galaxies at very high redshifts, the Herschel data allows us to rule out lower-redshift counterparts, and the XMM-Newton data allows us to remove quasar contaminants from our sample. This survey covers a volume >14X that of the largest previous survey for quiescent galaxies at z=3.5, and ~6X larger than that of the largest previous survey for star-forming galaxies at z=4. All of these data exist in the region soon to be observed by the Hobby Eberly Telescope Dark Energy Experiment (HETDEX), which will provide high-precision measures of halo masses and local density at z~3. Using this exquisite multi-wavelength dataset, we will measure the abundance of massive quiescent galaxies at z ~ 3-5, and, combining with measures of the halo masses and environment, compare properties of quiescent galaxies to star-forming galaxies to investigate the physical cause behind the quenching. We will also investigate the onset of quenching in star-forming galaxies in two ways, first by studying the relation between star formation rate and stellar mass, to search for a break in the typically-linear relation at high masses, and second by constraining the feedback

  16. SU-E-T-104: An Examination of Dose in the Buildup and Build-Down Regions

    International Nuclear Information System (INIS)

    Tome, W; Kuo, H; Phillips, J

    2015-01-01

    Purpose: To examine dose in the buildup and build-down regions and compare measurements made with various models and dosimeters Methods: Dose was examined in a 30×30cm 2 phantom of water-equivalent plastic with 10cm of backscatter for various field sizes. Examination was performed with radiochromic film and optically-stimulated-luminescent-dosimeter (OSLD) chips, and compared against a plane-parallel chamber with a correction factor applied to approximate the response of an extrapolation chamber. For the build-down region, a correction factor to account for table absorption and chamber orientation in the posterior-anterior direction was applied. The measurement depths used for the film were halfway through their sensitive volumes, and a polynomial best fit curve was used to determine the dose to their surfaces. This chamber was also compared with the dose expected in a clinical kernel-based computer model, and a clinical Boltzmann-transport-equation-based (BTE) computer model. The two models were also compared against each other for cases with air gaps in the buildup region. Results: Within 3mm, all dosimeters and models agreed with the chamber within 10% for all field sizes. At the entrance surface, film differed in comparison with the chamber from +90% to +15%, the BTE-model by +140 to +3%, and the kernel-based model by +20% to −25%, decreasing with increasing field size. At the exit surface, film differed in comparison with the chamber from −10% to −15%, the BTE-model by −53% to −50%, the kernel-based model by −55% to −57%, mostly independent of field size. Conclusion: The largest differences compared with the chamber were found at the surface for all field sizes. Differences decreased with increasing field size and increasing depth in phantom. Air gaps in the buildup region cause dose buildup to occur again post-gap, but the effect decreases with increasing phantom thickness prior to the gap

  17. Simulation of Electron-Cloud Build-Up for the Cold Arcs of the LHC and Comparison with Measured Data

    CERN Document Server

    Maury Cuna, H; Rumolo, G; Tavian, L; Zimmermann, F

    2011-01-01

    The electron cloud generated by synchrotron radiation or residual gas ionization is a concern for LHC operation and performance. We report the results of simulations studies which examine the electron cloud build-up, at injection energy, 3.5 TeV for various operation parameters. In particular, we determine the value of the secondary emission yield corresponding to the multipacting threshold, and investigate the electron density, and heat as a function of bunch intensity for dipoles and field-free regions. We also include a comparison between simulations results and measured heat-load data from the LHC scrubbing runs in 2011.

  18. Component build-up method for engineering analysis of missiles at low-to-high angles of attack

    Science.gov (United States)

    Hemsch, Michael J.

    1992-01-01

    Methods are presented for estimating the component build-up terms, with the exception of zero-lift drag, for missile airframes in steady flow and at arbitrary angles of attack and bank. The underlying and unifying bases of all these efforts are slender-body theory and its nonlinear extensions through the equivalent angle-of-attack concept. Emphasis is placed on the forces and moments which act on each of the fins, so that control cross-coupling effects as well as longitudinal and lateral-directional effects can be determined.

  19. Build-up of a liquid hydrogen target with extremely thin windows

    International Nuclear Information System (INIS)

    Jaeckle, V.G.

    1992-06-01

    Small hydrogen targets with only a few cubic millimeters of liquid have many advantages in experiments on accelerators with phase-space cooled particle beams. In order to achieve good suppression of systematic errors by secondary reactions in the target and in the target windows, the thickness of the foil window for a 1 mm target may only be 0.3 μm. A pressure difference of 200 mbar permits the use of such thin foils (with a diameter of 6 mm). A purely mechanical pressure control unit was built, which consists of soft bellows and a loading weight. The pressure difference from a vacuum, which is in the bellows, is set by the weight on the bellows. The working parameters were chosen so that deuterium, nitrogen and oxygen can be used. The pressure variations in the cell are only ± 2.5 mbar. A mixing of gaseous and liquid hydrogen in the target cell and the formation of bubbles due to free convection can be prevented. A quiet volume of liquid hydrogen free of bubbles was obtained. (orig./HP) [de

  20. Internal filtration and external filter cake build-up in sandstones

    NARCIS (Netherlands)

    Al-Abduwani, F.A.H.

    2005-01-01

    Water injection is an integral constituent of most field development scenarios. This injection may take place for secondary recovery and pressure maintenance such as sea water injection. Alternatively, it may take place as a waste water disposal method as in the case of produced water re-injection.

  1. Ion Composition and Energization in the Earth's Inner Magnetosphere and the Effects on Ring Current Buildup

    Science.gov (United States)

    Keika, K.; Kistler, L. M.; Brandt, P. C.

    2014-12-01

    In-situ observations and modeling work have confirmed that singly-charged oxygen ions, O+, which are of Earth's ionospheric origin, are heated/accelerated up to >100 keV in the magnetosphere. The energetic O+ population makes a significant contribution to the plasma pressure in the Earth's inner magnetosphere during magnetic storms, although under quiet conditions H+ dominates the plasma pressure. The pressure enhancements, which we term energization, are caused by adiabatic heating through earthward transport of source population in the plasma sheet, local acceleration in the inner magnetosphere and near-Earth plasma sheet, and enhanced ion supply from the topside ionosphere. The key issues regarding stronger O+ energization than H+ are non-adiabatic local acceleration, responsible for increase in O+ temperature, and more significant O+ supply than H+, responsible for increase in O+ density. Although several acceleration mechanisms and O+ supply processes have been proposed, it remains an open question what mechanism(s)/process(es) play the dominant role in stronger O+ energization. In this paper we summarize important spacecraft observations including those from Van Allen Probes, introduces the proposed mechanisms/processes that generate O+-rich energetic plasma population, and outlines possible scenarios of O+ pressure abundance in the Earth's inner magnetosphere.

  2. On the reversibility of cake buildup and compression in a membrane bioreactor

    DEFF Research Database (Denmark)

    Jørgensen, Mads Koustrup; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-01-01

    fouling depends on the relaxation time relative to the filtration time and pressure. Therefore, to observe a critical flux for irreversible fouling, the relaxation times applied in the stepping approach should be customized to be sufficient to remove all removable fouling. The model suggests...

  3. Diurnal blood pressure changes.

    Science.gov (United States)

    Asayama, Kei; Satoh, Michihiro; Kikuya, Masahiro

    2018-05-23

    The definition of diurnal blood pressure changes varies widely, which can be confusing. Short-term blood pressure variability during a 24-h period and the dipping status of diurnal blood pressure can be captured by ambulatory blood pressure monitoring, and these metrics are reported to have prognostic significance for cardiovascular complications. Morning blood pressure surge also indicates this risk, but its effect may be limited to populations with specific conditions. Meanwhile, the combined use of conventional office blood pressure and out-of-office blood pressure allows us to identify people with white-coat and masked hypertension. Current home devices can measure nocturnal blood pressure during sleep more conveniently than ambulatory monitoring; however, we should pay attention to blood pressure measurement conditions regardless of whether they are in a home, ambulatory, or office setting. The relatively poor reproducibility of diurnal blood pressure changes, including the nocturnal fall of blood pressure, is another underestimated issue to be addressed. Although information on diurnal blood pressure changes is expected to be used more effectively in the future, we should also keep in mind that blood pressure levels have remained central to the primary and secondary prevention of blood pressure-related cardiovascular diseases in clinical practice.

  4. Role of urban surface roughness in road-deposited sediment build-up and wash-off

    Science.gov (United States)

    Zhao, Hongtao; Jiang, Qian; Xie, Wenxia; Li, Xuyong; Yin, Chengqing

    2018-05-01

    Urban road surface roughness is one of the most important factors in estimation of surface runoff loads caused by road-deposited sediment (RDS) wash-off and design of its control measures. However, because of a lack of experimental data to distinguish the role of surface roughness, the effects of surface roughness on RDS accumulation and release are not clear. In this study, paired asphalt and concrete road surfaces and rainfall simulation designs were used to distinguish the role of surface roughness in RDS build-up and wash-off. Our results showed that typical asphalt surfaces often have higher depression depths than typical concrete surfaces, indicating that asphalt surfaces are relatively rougher than concrete surface. Asphalt surfaces can retain a larger RDS amount, relative higher percentage of coarser particles, larger RDS wash-off loads, and lower wash-off percentage, than concrete surfaces. Surface roughness has different effects in RDS motilities with different particle sizes during rainfall runoff, and the settleable particles (44-149 μm) were notably influenced by it. Furthermore, the first flush phenomenon tended to be greater on relatively smooth surfaces than relatively rough surfaces. Overall, surface roughness plays an important role in influencing the complete process of RDS build-up and wash-off on different road characteristics.

  5. Water chemistry and radiation buildup at the Commonwealth Edison Company LaSalle-1 BWR. Final report

    International Nuclear Information System (INIS)

    Earls, C.E.; Blok, J.

    1986-09-01

    This report presents the results of a comprehensive study of the water quality and radiation buildup at the LaSalle County Unit 2 boiling warer reactor (BWR). The purpose of the study was to determine the effect of corrosion product inputs from the forward pumped heater drains on overall water quality. Since the drains are pumped into the feedwater line without filtration or demineralization, corrosion products in these streams will directly add to the impurity levels of the final feedwater. At LaSalle, the forward pumped heater drains contributed less to the feedwater impurities, on average, than the effluent of the condensate demineralizer. The feedwater quality at LaSalle was generally in the ''acceptable'' range. Nevertheless, significant water chemistry improvements, especially in reducing the corrosion product spikes associated with power or flow transients, is highly desirable for this plant. Such improvements should begin with a more consistent quality of demineralizer operation. Quantitative gamma scans of the primary system piping at LaSalle 2 were carried out in the course of the water chemistry study. Although the cumulative operational exposure of the plant was relatively limited at the time this study was carried out, the radiation buildup rate did appear to be rapid (in fact, among the most rapid) compared to other similar BWRs

  6. Determination of point isotropic buildup factors of gamma rays including incoherent and coherent scattering for aluminum, iron, lead, and water by discrete ordinates method

    International Nuclear Information System (INIS)

    Kitsos, S.; Assad, A.; Diop, C.M.; Nimal, J.C.

    1994-01-01

    Exposure and energy absorption buildup factors for aluminum, iron, lead, and water are calculated by the SNID discrete ordinates code for an isotropic point source in a homogeneous medium. The calculation of the buildup factors takes into account the effects of both bound-electron Compton (incoherent) and coherent (Rayleigh) scattering. A comparison with buildup factors from the literature shows that these two effects greatly increase the buildup factors for energies below a few hundred kilo-electron-volts, and thus the new results are improved relative to the experiment. This greater accuracy is due to the increase in the linear attenuation coefficient, which leads to the calculation of the buildup factors for a mean free path with a smaller shield thickness. On the other hand, for the same shield thickness, exposure increases when only incoherent scattering is included and decreases when only coherent scattering is included, so that the exposure finally decreases when both effects are included. Great care must also be taken when checking the approximations for gamma-ray deep-penetration transport calculations, as well as for the cross-section treatment and origin

  7. Reservoir response to thermal and high-pressure well stimulation efforts at Raft River, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Plummer, Mitchell [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bradford, Jacob [Energy & Geoscience Institute at the Univ. of Utah, Salt Lake City, UT (United States); Moore, Joseph [Energy & Geoscience Institute at the Univ. of Utah, Salt Lake City, UT (United States); Podgorney, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    An injection stimulation test begun at the Raft River geothermal reservoir in June, 2013 has produced a wealth of data describing well and reservoir response via high-resolution temperature logging and distributed temperature sensing, seismic monitoring, periodic borehole televiewer logging, periodic stepped flow rate tests and tracer injections before and after stimulation efforts. One of the primary measures of response to the stimulation is the relationship between fluid pressure and flow rate, short-term during forced flow rate changes and the long-term change in injectivity. In this paper we examine that hydraulic response using standard pumping test analysis methods, largely because pressure response to the stimulation was not detected, or measurable, in other wells. Analysis of stepped rate flow tests supports the inference from other data that a large fracture, with a radial extent of one to several meters, intersects the well in the target reservoir, suggests that the flow regime is radial to a distance of only several meters and demonstrates that the pressure build-up cone reaches an effective constant head at that distance. The well’s longer term hydraulic response demonstrated continually increasing injectivity but at a dramatically faster rate later from ~2 years out and continuing to the present. The net change in injectivity is significantly greater than observed in other longterm injectivity monitoring studies, with an approximately 150–fold increase occurring over ~2.5 years. While gradually increasing injectivity is a likely consequence of slow migration of a cooling front, and consequent dilation of fractures, the steady, ongoing, rate of increase is contrary to what would be expected in a radial or linear flow regime, where the cooling front would slow with time. As a result, occasional step-like changes in injectivity, immediately following high-flow rate tests suggest that hydro shearing during high-pressure testing altered the near

  8. Measuring fluid pressure

    International Nuclear Information System (INIS)

    Lee, A.S.

    1978-01-01

    A method and apparatus are described for measuring the pressure of a fluid having characteristics that make it unsuitable for connection directly to a pressure gauge. The method is particularly suitable for the periodic measurement of the pressure of a supply of liquid Na to Na-lubricated bearings of pumps for pumping Na from a reservoir to the bearing via a filter, the reservoir being contained in a closed vessel containing an inert blanket gas, such as Ar, above the Na. (UK)

  9. Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A.I.; Som, S.; Aggarwal, Suresh K. [University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL (United States); Kastengren, A.L.; El-Hannouny, E.M.; Longman, D.E.; Powell, C.F. [Argonne National Laboratory, Energy Systems Division, Argonne, IL (United States)

    2009-07-15

    A quantitative and time-resolved X-ray radiography technique has been used for detailed measurements of high-pressure fuel sprays in the near-nozzle region of a diesel engine injector. The technique provides high spatial and temporal resolution, especially in the relatively dense core region. A single spray plume from a hydraulically actuated electronically controlled unit injector model 315B injector with a 6-hole nozzle was isolated and studied at engine-like densities for two different injection pressures. Optical spray imaging was also employed to evaluate the effectiveness of the shield used to isolate a single spray plume. The steady state fuel distributions for both injection pressures are similar and show a dense spray region along the axis of the spray, with the on-axis spray density decreasing as the spray progresses downstream. The higher injection pressure case exhibits a larger cone angle and spray broadening at the exit of the nozzle. For some time periods, the near-nozzle penetration speed is lower for the high injection pressure case than the low injection pressure case, which is unexpected, but can be attributed to the needle and flow dynamics inside the injector causing slower pressure build-up for the former case. Rate of injection testing was performed to further understand near-nozzle behavior. Mass distribution data were obtained and used to find mass-averaged velocity of the spray. Comparisons of the radiography data with that from a common rail single-hole light duty injectors under similar injection conditions show several significant differences. The current data show a larger cone angle and lower penetration speed than that from the light-duty injector. Moreover, these data display a Gaussian mass distribution across the spray near the injector, whereas in previous light-duty injector measurements, the mass distribution had steeper sides and a flatter peak. Measurements are also used to examine the spray models in the STAR-CD software

  10. Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector

    Science.gov (United States)

    Ramírez, A. I.; Som, S.; Aggarwal, Suresh K.; Kastengren, A. L.; El-Hannouny, E. M.; Longman, D. E.; Powell, C. F.

    2009-07-01

    A quantitative and time-resolved X-ray radiography technique has been used for detailed measurements of high-pressure fuel sprays in the near-nozzle region of a diesel engine injector. The technique provides high spatial and temporal resolution, especially in the relatively dense core region. A single spray plume from a hydraulically actuated electronically controlled unit injector model 315B injector with a 6-hole nozzle was isolated and studied at engine-like densities for two different injection pressures. Optical spray imaging was also employed to evaluate the effectiveness of the shield used to isolate a single spray plume. The steady state fuel distributions for both injection pressures are similar and show a dense spray region along the axis of the spray, with the on-axis spray density decreasing as the spray progresses downstream. The higher injection pressure case exhibits a larger cone angle and spray broadening at the exit of the nozzle. For some time periods, the near-nozzle penetration speed is lower for the high injection pressure case than the low injection pressure case, which is unexpected, but can be attributed to the needle and flow dynamics inside the injector causing slower pressure build-up for the former case. Rate of injection testing was performed to further understand near-nozzle behavior. Mass distribution data were obtained and used to find mass-averaged velocity of the spray. Comparisons of the radiography data with that from a common rail single-hole light duty injectors under similar injection conditions show several significant differences. The current data show a larger cone angle and lower penetration speed than that from the light-duty injector. Moreover, these data display a Gaussian mass distribution across the spray near the injector, whereas in previous light-duty injector measurements, the mass distribution had steeper sides and a flatter peak. Measurements are also used to examine the spray models in the STAR-CD software.

  11. Build-up and decay of fuel actinides in the fuel cycle of nuclear reactors

    International Nuclear Information System (INIS)

    Tasaka, Kanji; Kikuchi, Yasuyuki; Shindo, Ryuichi; Yoshida, Hiroyuki; Yasukawa, Shigeru

    1976-05-01

    For boiling water reactors, pressurized light-water reactors, pressure-tube-type heavy water reactors, high-temperature gas-cooled reactors, and sodium-cooled fast breeder reactors, uranium fueled and mixed-oxide fueled, each of 1000 MWe, the following have been studied: (1) quantities of plutonium and other fuel actinides built up in the reactor, (2) cooling behaviors of activities of plutonium and other fuel actinides in the spent fuels, and (3) activities of plutonium and other fuel actinides in the high-level reprocessing wastes as a function of storage time. The neutron cross section and decay data of respective actinide nuclides are presented, with their evaluations. For effective utilization of the uranium resources and easy reprocessing and high-level waste management, a thermal reactor must be fueled with uranium; the plutonium produced in a thermal reactor should be used in a fast reactor; and the plutonium produced in the blanket of a fast reactor is more appropriate for a fast reactor than that from a thermal reactor. (auth.)

  12. Effect of simulated pulpal pressure on all-in-one adhesive bond strengths to dentine.

    Science.gov (United States)

    Hosaka, Keiichi; Nakajima, Masatoshi; Yamauti, Monica; Aksornmuang, Juthatip; Ikeda, Masaomi; Foxton, Richard M; Pashley, David H; Tagami, Junji

    2007-03-01

    To evaluate the durability of all-in-one adhesive systems bonded to dentine with and without simulated hydrostatic pulpal pressure (PP). Flat dentine surfaces of extracted human molars were prepared. Two all-in-one adhesive systems, One-Up Bond F (OBF) (Tokuyama Corp., Tokyo, Japan), and Fluoro Bond Shake One (FBS) (Shofu Co., Kyoto, Japan) were applied to the dentine surfaces under either a PP of 0 or 15cm H(2)O. Then, resin composite build-ups were made. The specimens bonded under pressure were stored in 37 degrees C water for 24h, 1 and 3 months under 15cm H(2)O PP. Specimens not bonded under pressure were stored under zero PP. After storage, the specimens were sectioned into slabs that were trimmed to hourglass shapes and subjected to micro-tensile bond testing (muTBS). The data were analysed using two-way ANOVA and Holm-Sidak HSD multiple comparison tests (alpha=0.05). The muTBS of OBF fell significantly (phydrostatic pressure storage fell significantly over the 3 months period, the decrease was less than half as much as specimens stored under PP. In FBS bonded specimens, although there was no significant difference between the muTBS with and without hydrostatic pulpal pressure at 24h, by 1 and 3 months of storage under PP, significant reductions were seen compared with the control group without PP. The muTBS of OBF bonded specimens was lowered more by simulated PP than by storage time; specimens bonded with FBS were not sensitive to storage time in the absence of PP, but showed lower bond strengths at 1 and 3 months in the presence of PP.

  13. Monte Carlo simulation of x-ray buildup factors of lead and its applications in shielding of diagnostic x-ray facilities

    International Nuclear Information System (INIS)

    Kharrati, Hedi; Agrebi, Amel; Karaoui, Mohamed-Karim

    2007-01-01

    X-ray buildup factors of lead in broad beam geometry for energies from 15 to 150 keV are determined using the general purpose Monte Carlo N-particle radiation transport computer code (MCNP4C). The obtained buildup factors data are fitted to a modified three parameter Archer et al. model for ease in calculating the broad beam transmission with computer at any tube potentials/filters combinations in diagnostic energies range. An example for their use to compute the broad beam transmission at 70, 100, 120, and 140 kVp is given. The calculated broad beam transmission is compared to data derived from literature, presenting good agreement. Therefore, the combination of the buildup factors data as determined and a mathematical model to generate x-ray spectra provide a computationally based solution to broad beam transmission for lead barriers in shielding x-ray facilities

  14. Measurements of the Exerted Pressure by Pelvic Circumferential Compression Devices

    Science.gov (United States)

    Knops, Simon P; van Riel, Marcel P.J.M; Goossens, Richard H.M; van Lieshout, Esther M.M; Patka, Peter; Schipper, Inger B

    2010-01-01

    Background: Data on the efficacy and safety of non-invasive Pelvic Circumferential Compression Devices (PCCDs) is limited. Tissue damage may occur if a continuous pressure on the skin exceeding 9.3 kPa is sustained for more than two or three hours. The aim of this study was to gain insight into the pressure build-up at the interface, by measuring the PCCD-induced pressure when applying pulling forces to three different PCCDs (Pelvic Binder® , SAM-Sling ® and T-POD® ) in a simplified model. Methods: The resulting exerted pressures were measured at four ‘anatomical’ locations (right, left, posterior and anterior) in a model using a pressure measurement system consisting of pressure cuffs. Results: The exerted pressure varied substantially between the locations as well as between the PCCDs. Maximum pressures ranged from 18.9-23.3 kPa and from 19.2-27.5 kPa at the right location and left location, respectively. Pressures at the posterior location stayed below 18 kPa. At the anterior location pressures varied markedly between the different PCCDs. Conclusion: The circumferential compression by the different PCCDs showed high pressures measured at the four locations using a simplified model. Difference in design and functional characteristics of the PCCDs resulted in different pressure build-up at the four locations. When following the manufacturer’s instructions, the exerted pressure of all three PCCDs tested exceeded the tissue damaging level (9.3 kPa). In case of prolonged use in a clinical situation this might put patients at risk for developing tissue damage. PMID:20361001

  15. Weight and blood pressure response to weight management and sibutramine in diabetic and non-diabetic high-risk patients: an analysis from the 6-week lead-in period of the sibutramine cardiovascular outcomes (SCOUT) trial

    DEFF Research Database (Denmark)

    Van Gaal, L F; Caterson, I D; Coutinho, W

    2010-01-01

    To assess treatment responses to sibutramine and weight management in diabetic patients during the lead-in period of the Sibutramine Cardiovascular OUTcomes (SCOUT) trial.......To assess treatment responses to sibutramine and weight management in diabetic patients during the lead-in period of the Sibutramine Cardiovascular OUTcomes (SCOUT) trial....

  16. Endodontic treatment and esthetic management of a primary double tooth with direct composite using silicone buildup guide

    Directory of Open Access Journals (Sweden)

    Vinaya Kumar Kulkarni

    2012-01-01

    Full Text Available Gemination and fusion are morphological dental anomalies, characterized by the formation of a clinically wide tooth. Gemination occurs when one tooth bud tries to divide, while fusion occurs if two buds unite. The terms double teeth, double formation, conjoined teeth, geminifusion, vicinifusion and dental twinning are often used to describe fusion and gemination. Double teeth are associated with clinical problems such as poor esthetics, spacing problems and caries susceptibility. Management of such cases requires a comprehensive knowledge of the clinical entity as well as the problems associated with it. This report presents a case of primary double tooth in a 6-year-old boy involving maxillary left central incisor. The anomalous tooth was carious and pulpally involved. This was treated conservatively by endodontic treatment and esthetic rehabilitation was done with direct composite restoration using a silicone buildup guide. The treated tooth was followed up until exfoliation.

  17. Modeling of gamma ray energy-absorption buildup factors for thermoluminescent dosimetric materials using multilayer perceptron neural network

    DEFF Research Database (Denmark)

    Kucuk, Nil; Manohara, S.R.; Hanagodimath, S.M.

    2013-01-01

    In this work, multilayered perceptron neural networks (MLPNNs) were presented for the computation of the gamma-ray energy absorption buildup factors (BA) of seven thermoluminescent dosimetric (TLD) materials [LiF, BeO, Na2B4O7, CaSO4, Li2B4O7, KMgF3, Ca3(PO4)2] in the energy region 0.015–15Me......V, and for penetration depths up to 10 mfp (mean-free-path). The MLPNNs have been trained by a Levenberg–Marquardt learning algorithm. The developed model is in 99% agreement with the ANSI/ANS-6.4.3 standard data set. Furthermore, the model is fast and does not require tremendous computational efforts. The estimated BA...

  18. Applications of Monte Carlo codes to a study of gamma-ray buildup factors, skyshine and duct streaming

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, H. [High Energy Accelerator Research Organization (KEK), Ibaraki (Japan)

    2001-07-01

    Many shielding calculations for gamma-rays have continued to rely on point-kernel methods incorporating buildup factor data. Line beam or conical beam response functions, which are calculated using a Monte Carlo code, for skyshine problems are useful to estimate the skyshine dose from various facilities. A simple calculation method for duct streaming was proposed using the parameters calculated by the Monte Carlo code. It is therefore important to study, improve and produce basic parameters related to old, but still important, problems in the fields of radiation shielding using the Monte Carlo code. In this paper, these studies performed by several groups in Japan as applications of the Monte Carlo method are discussed. (orig.)

  19. Resonant laser power build-up in ALPS-A 'light shining through a wall' experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ehret, Klaus [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Frede, Maik [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany); Ghazaryan, Samvel [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Hildebrandt, Matthias [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany); Knabbe, Ernst-Axel [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Kracht, Dietmar [Laser Zentrum Hannover e.V., Hollerithallee 8, D-30419 Hannover (Germany); Lindner, Axel, E-mail: axel.lindner@desy.d [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); List, Jenny [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Meier, Tobias [Max-Planck-Institute for Gravitational Physics, Albert-Einstein-Institute, and Institut fuer Gravitationsphysik, Leibniz Universitaet, Hannover, Callinstrasse 38, D-30167 Hannover (Germany); Meyer, Niels; Notz, Dieter; Redondo, Javier; Ringwald, Andreas [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany); Wiedemann, Guenter [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany); Willke, Benno [Max-Planck-Institute for Gravitational Physics, Albert-Einstein-Institute, and Institut fuer Gravitationsphysik, Leibniz Universitaet, Hannover, Callinstrasse 38, D-30167 Hannover (Germany)

    2009-12-21

    The ALPS Collaboration runs a 'light shining through a wall' (LSW) experiment to search for photon oscillations into 'weakly interacting sub-eV particles' (WISPs) inside of a superconducting HERA dipole magnet at the site of DESY. In this paper we report on the first successful integration of a large-scale optical resonant cavity to boost the available power for WISP production in this type of experiments. The key elements are a frequency tunable narrow line-width continuous wave laser acting as the primary light source and an electronic feed-back control loop to stabilize the power build-up. We describe and characterize our apparatus and demonstrate the data analysis procedures on the basis of a brief exemplary run.

  20. Evaluation of pollutant build-up and wash-off from selected land uses at the Port of Brisbane, Australia.

    Science.gov (United States)

    Goonetilleke, Ashantha; Egodawatta, Prasanna; Kitchen, Brad

    2009-02-01

    The quality of stormwater runoff from seaports can be an important source of pollution to the marine environment. Currently, little knowledge exists with regards to the pollutant generation capacity specific to seaports as they do not necessarily compare well with conventional urban land use. The research project focussed on the assessment of pollutant build-up and wash-off. The study was undertaken using rainfall simulation and small impervious plots for different port land uses with the results obtained compared to typical urban land uses. The study outcomes confirmed that the Port land uses exhibit comparatively lower pollutant concentrations. However, the pollutant characteristics varied across different land uses. Hence, the provision of stereotypical water quality improvement measures could be of limited value. Particle size < 150microm was predominant in suspended solids. Therefore, if suspended solids are targeted as the surrogate parameter for water quality improvement, this particle size range needs to be removed.

  1. Resonant laser power build-up in ALPS. A 'light-shining-through-walls' experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ehret, Klaus; Ghazaryan, Samvel [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Frede, Maik [Laser Zentrum Hannover e.V. (DE)] (and others)

    2009-05-15

    The ALPS collaboration runs a light-shining-through-walls (LSW) experiment to search for photon oscillations into weakly interacting sub-eV particles (WISPs) inside of a superconducting HERA dipole magnet at the site of DESY. In this paper we report on the first successful integration of a large-scale optical cavity to boost the available power for WISP production in this type of experiments. The key elements are a frequency tunable narrow line-width continuous wave laser acting as the primary light source and an electronic feed-back control loop to stabilize the power build-up. We describe and characterize our apparatus and demonstrate the data analysis procedures on the basis of a brief exemplary run. (orig.)

  2. The computation of the build-up of long-lived radioisotopes on the surface of primary circuits and the ion exchange material of BWR

    International Nuclear Information System (INIS)

    Lundgren, K.

    1980-06-01

    The buildup of radionuclides on the surface of the primary circuits and in the ion exchange material is calculated. The computation is made by the computer code 'CRUD'. The buildup is interesting from the viewpoint of nuclear waste. Oskarshamn 2 is chosen as the reference plant. An extrapolation is made for 20 years of operation. Calculation are givin for Mn54, Fe55, Co60, Ni59, Ni63 and Zn65. The constants of deposition and disharge are determined by fitting the values. (G.B.)

  3. Evaluation of surface and build-up region dose for intensity-modulated radiation therapy in head and neck cancer

    International Nuclear Information System (INIS)

    Chung, Heeteak; Jin, Hosang; Dempsey, James F.; Liu, Chihray; Palta, Jatinder; Suh, Tae-Suk; Kim, Siyong

    2005-01-01

    Despite much development, there remains dosimetric uncertainty in the surface and build-up regions in intensity-modulated radiation therapy treatment plans for head and neck cancers. Experiments were performed to determine the dosimetric discrepancies in the surface and build-up region between the treatment planning system (TPS) prediction and experimental measurement using radiochromic film. A head and neck compression film phantom was constructed from two semicylindrical solid water slabs. Treatment plans were generated using two commercial TPSs (PINNACLE3 and CORVUS) for two cases, one with a shallow (∼0.5 cm depth) target and another with a deep (∼6 cm depth) target. The plans were evaluated for a 54 Gy prescribed dose. For each case, two pieces of radiochromic film were used for dose measurement. A small piece of film strip was placed on the surface and another was inserted within the phantom. Overall, both TPSs showed good agreement with the measurement. For the shallow target case, the dose differences were within ±300 cGy (5.6% with respect to the prescribed dose) for PINNACLE3 and ±240 cGy (4.4%) for CORVUS in 90% of the region of interest. For the deep target case, the dose differences were ±350 (6.5%) for PINNACLE3 and ±260 cGy (4.8%) for CORVUS in 90% of the region of interest. However, it was found that there were significant discrepancies from the surface to about 0.2 cm in depth for both the shallow and deep target cases. It was concluded that both TPSs overestimated the surface dose for both shallow and deep target cases. The amount of overestimation ranges from 400 to 1000 cGy (∼7.4% to 18.5% with respect to the prescribed dose, 5400 cGy)

  4. The rudist buildup depositional model, reservoir architecture and development strategy of the cretaceous Sarvak formation of Southwest Iran

    Directory of Open Access Journals (Sweden)

    Yang Du

    2015-03-01

    Full Text Available This paper studies the lithofacies, sedimentary facies, depositional models and reservoir architecture of the rudist-bearing Sar-3 zone of Cretaceous Sarvak in the Southwest of Iran by utilizing coring, thin section, XRD data of five coring wells and 3D seismic data. Research results include the following: According to lithofacies features and their association, the rudist-mound and tidal flat are the main microfacies in the Sar-3 depositional time. By investigating the regional tectonic setting and seismic interpretation, a depositional model was built for the Sar-3 zone, which highlights four key points: 1 The distribution of the rudist-buildup is controlled by the paleo-high. 2 The build-up outside of the wide colonize stage but reached the wave-base level in a short time by regression and formation uplift, and was destroyed by the high energy current, then forming the moundy allochthonous deposition after being dispersed and redeposited. 3 The tidal flat develops widely in the upper Sar-3, and the deposition thickness depends on the paleo-structure. The tidal channel develops in the valley and fringe of the Paleo-structure. 4 The exposure within the leaching effect by the meteoric water of the top of Sar-3 is the main controlling factor of the reservoir vertical architecture. The Sar-3 zone featured as the dualistic architecture consists of two regions: the lower is the rudist reef limestone reservoir and the upper is the tidal condense limestone interlayer. The thickness of each is controlled by the paleo-structure. The Paleo-high zone is the preferential development zone. Based on reservoir characteristics of the different zones, a targeted development strategy has been proposed. Keeping the trajectory in the middle of the oil-layer in the paleo-high, and in the paleo-low, make the trajectory crossing the oil-zone and then keep it in the lower.

  5. A resin composite material containing an eugenol derivative for intracanal post cementation and core build-up restoration.

    Science.gov (United States)

    Almaroof, A; Rojo, L; Mannocci, F; Deb, S

    2016-02-01

    To formulate and evaluate new dual cured resin composite based on the inclusion of eugenyl methacrylate monomer (EgMA) with Bis-GMA/TEGDMA resin systems for intracanal post cementation and core build-up restoration of endodontically treated teeth. EgMA was synthesized and incorporated at 5% (BTEg5) or 10% (BTEg10) into dual-cure formulations. Curing properties, viscosity, Tg, radiopacity, static and dynamic mechanical properties of the composites were determined and compared with Clearfil™DC Core-Plus, a commercial dual-cure, two-component composite. Statistical analysis of the data was performed with ANOVA and the Tukey's post-hoc test. The experimental composites were successfully prepared, which exhibited excellent curing depths of 4.9, 4.7 and 4.2 mm for BTEg0, BTEg5 and BTEg10 respectively, which were significantly higher than Clearfil™DC. However, the inclusion of EgMA initially led to a lower degree of cure, which increased when measured at 24 h with values comparable to formulations without EgMA, indicating post-curing. The inclusion of EgMA also lowered the polymerization exotherm thereby reducing the potential of thermal damage to host tissue. Both thermal and viscoelastic analyses confirmed the ability of the monomer to reduce the stiffness of the composites by forming a branched network. The compressive strength of BTEg5 was significantly higher than the control whilst flexural strength increased significantly from 95.9 to 114.8 MPa (BTEg5) and 121.9 MPa (BTEg10). Radiopacity of the composites was equivalent to ∼3 mm Al allowing efficient diagnosis. The incorporation of EgMA within polymerizable formulations provides a novel approach to prepare reinforced resin composite material for intracanal post cementation and core build-up and the potential to impart antibacterial properties of eugenol to endodontic restorations. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Blood pressure

    Science.gov (United States)

    Normal blood pressure is important for proper blood flow to the body's organs and tissues. The force of the blood on the walls of the arteries is called blood pressure. Blood pressure is measured both as the heart ...

  7. PAD WELDING EFFECT ON CRANKSHAFT LENGTH WHILE MAKING BUILD-UP PROCESS

    Directory of Open Access Journals (Sweden)

    T. V. Vigerina

    2011-01-01

    Full Text Available The paper reveals a pad welding effect on axial sizes of a crankshaft to be built-up and a dependence of axial deformation of built-up element on an elasticity modulus, a heating temperature and thermal coefficient of linear expansion of an element and a plating, weave bead sizes. This dependence enables to forecast tensile stresses in the plating. The paper contains justification on limitation of axial deformation of the built crank due to decrease of pad welding numbers up to only one during the whole period of its lifetime and carrying out  resource-saving measures.

  8. Measurements of dose on build-up region, surface dose and outlet dose by a 10 MeV Linear accelerator

    International Nuclear Information System (INIS)

    Souza, C.N. de; Khoury, H.J.

    1987-01-01

    The dose on buildup region and the surface dose for a 10 MeV photon beam from a linear acelerator (Mevatrom-74, Siemens) is studied. The influence of the tray of polycarbonate on the surface dose is determined. (M.A.C.) [pt

  9. Generation of point isotropic source dose buildup factor data for the PFBR special concretes in a form compatible for usage in point kernel computer code QAD-CGGP

    International Nuclear Information System (INIS)

    Radhakrishnan, G.

    2003-01-01

    Full text: Around the PFBR (Prototype Fast Breeder Reactor) reactor assembly, in the peripheral shields special concretes of density 2.4 g/cm 3 and 3.6 g/cm 3 are to be used in complex geometrical shapes. Point-kernel computer code like QAD-CGGP, written for complex shield geometry comes in handy for the shield design optimization of peripheral shields. QAD-CGGP requires data base for the buildup factor data and it contains only ordinary concrete of density 2.3 g/cm 3 . In order to extend the data base for the PFBR special concretes, point isotropic source dose buildup factors have been generated by Monte Carlo method using the computer code MCNP-4A. For the above mentioned special concretes, buildup factor data have been generated in the energy range 0.5 MeV to 10.0 MeV with the thickness ranging from 1 mean free paths (mfp) to 40 mfp. Capo's formula fit of the buildup factor data compatible with QAD-CGGP has been attempted

  10. The effect of zinc injection into PWR primary coolant on the reduction of radiation buildup and corrosion control. The solubilities of zinc, nickel and cobalt spinel oxides

    International Nuclear Information System (INIS)

    Miyajima, Kaori; Hirano, Hideo

    1999-01-01

    The use of zinc injection into PWR primary coolant to reduce radiation buildup has been widely studied, and te reduction effect has been experimentally confirmed. However, some items, such as the optimal concentration of zinc required to reduce radiation buildup, the corrosion control effect of zinc injection, and the influence of zinc injection on the integrity of fuel cladding, have not been clarified yet. In particular, the corrosion suppression effect of zinc remains unconfirmed. Therefore, it is necessary to measure and calculate the solubilities of zinc and nickel spinel oxides, which are formed on the surface of Ni-based alloys in PWR primary systems. In this study, in order to assess the effectiveness of zinc injection in the reduction of radiation buildup and the corrosion control of Ni-based alloy, the potential-pH diagrams for Zn-Cr-H 2 O, Ni-Cr-H 2 O, and Co-Cr-H 2 O systems at 300degC were constructed and the solubilities of Zn-Cr, Ni-Cr, and Co-Cr spinel oxides were calculated. It is concluded that under pH conditions for which NiCr 2 O 4 is stable, zinc injection is effective in corrosion control as well as in reducing radiation buildup. (author)

  11. RIBD-IRT, Isotope Buildup and Isotope Decay from Fission Source

    International Nuclear Information System (INIS)

    1990-01-01

    1 - Description of problem or function: RIBD-IRT calculates isotopic concentrations resulting from two fission sources with normal down- chain decay by beta emission and isomeric transfers and inter-chain coupling resulting from (n,gamma) reactions. Calculations can be made to follow an irradiation history through an unlimited number of step changes of unrestricted duration and variability including shutdown periods, restarts at different power levels and/or any other level changes. In addition, the program permits to track and modify the concentration of individual elements as they decay with time following reactor shutdown. Tracking individual elements enables one to estimate time-dependent source terms for a hypothetical LOCA based on known or postulated fission product release mechanisms. 2 - Method of solution: RIBD-IRT is a grid processor. It organizes the various members described by the fission product library data into a grid with the various linkages established from chain branching data, yield data, and neutron capture cross sections with their branching ratios. Radioactive decay includes not only the simple member-to-member cascade but also the more complex forms where branching may be partially or completely skip one or two intervening members

  12. Unexpected 226Ra build-up in wet-process phosphoric-acid plants

    International Nuclear Information System (INIS)

    Lardinoye, M.H.; Weterings, K.; Berg, W.B. van de

    1982-01-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filters. This higher radiation level is caused by radium which is present in very low concentrations in the phosphates used for fertilizer production. Detectable radiation levels around vessels and piping in other phosphoric-acid works have since been determined. In all factories the filter part and especially the washing-acid section showed the highest radiation level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of barium sulphate and calcium sulphate with a higher radium concentration is formed. The radium ions appeared to be incorporated in the barium sulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal contamination in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning the equipment in which the radioactive scaling is formed. (author)

  13. Unexpected /sup 226/Ra build-up in wet-process phosphoric-acid plants

    Energy Technology Data Exchange (ETDEWEB)

    Lardinoye, M.H.; Weterings, K. (Stamicarbon B.V., Geleen (Netherlands)); van de Berg, W.B. (Unie van Kunstmestfabrieken, Utrecht (Netherlands))

    1982-04-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filters. This higher radiation level is caused by radium which is present in very low concentrations in the phosphates used for fertilizer production. Detectable radiation levels around vessels and piping in other phosphoric-acid works have since been determined. In all factories the filter part and especially the washing-acid section showed the highest radiation level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of barium sulphate and calcium sulphate with a higher radium concentration is formed. The radium ions appeared to be incorporated in the barium sulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal contamination in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning the equipment in which the radioactive scaling is formed.

  14. Unexpected 226Ra build-up in wet-process phosphoric-acid plants.

    Science.gov (United States)

    Lardinoye, M H; Weterings, K; van de Berg, W B

    1982-04-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filtres. This higher radiation level is caused by radium, which, as a decay product in the 238U series, is present in very low concentrations (1-50 pCi 226R/g) in the phosphates used for fertilizer production. Specific research later on established that there were detectable radiation levels around vessels and piping in other phosphoric-acid works as well. It turned out that in all factories the filter part, and especially the washing-acid section showed the highest radiation-level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of bariumsulphate and calciumsulphate with a higher radiumconcentration (+/- 0.1 Ci/g) is formed. The radium ions appeared to be incorporated in the bariumsulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal pollution, for example in cleaning operations by radio-active intake or inhallation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning (every 1-3 yr) the equipment in which the radio-active scaling is formed.

  15. Unexpected /sup 226/Ra build-up in wet-process phosphoric-acid plants

    Energy Technology Data Exchange (ETDEWEB)

    Lardinoye, M.H.; Weterings, K.; van de Berg, W.B.

    1982-04-01

    During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filtres. This higher radiation level is caused by radium, which, as a decay product in the /sup 238/U series, is present in very low concentrations (1-50 pCi 226R/g) in the phosphates used for fertilizer production. Specific research later on established that there were detectable radiation levels around vessels and piping in other phosphoric-acid works as well. It turned out that in all factories the filter part, and especially the washing-acid section showed the highest radiation-level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of bariumsulfate and calciumsulfate with a higher radium concentration (+/- 0.1 Ci/g) is formed. The radium ions appeared to be incorporated in the bariumsulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal pollution, for example in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning (every 1-3 yr) the equipment in which the radioactive scaling is formed.

  16. A Measurement and Analysis of Buildup Region Dose for Open Field Photon Beams (Cobalt-60 through 24 MV)

    International Nuclear Information System (INIS)

    McCullough, Edwin C.

    2015-01-01

    The central axis depth dose in the build-up region (surface to d_m_a_x) of single open field photon beams (cobalt-60 through 24 MV) has been measured utilizing parallel plate and extrapolation chamber methodology. These data were used to derive, for a prescription dose of 100 cGy, values of surface dose, the maximum value of dose along the central axis (D_m_a_x) and the depth (nearest the surface) at which 90% of the prescription dose occurs (d_9_0). For both single and parallel opposed pair (POP) open field configurations, data are presented at field sizes of 5 × 5, 15 × 15 and 25 × 25 cm"2 for prescription depths of 10, 15 and 20 cm (midplane for POP). For the treatment machines, field sizes, and prescription depths studied, it is possible to conclude that: for single open field irradiation, surface dose values (as a percentage of the prescription dose) can be either low (<10%) or comparable to the prescription dose itself; for POP open fields, surface dose values are relatively independent of photon energy and midplane depth, and range between 30% and 70% of prescription dose, being principally dependent on field size; the depth of the initial 90 cGy point for a prescription dose of 100 cGy, d_9_0, was larger for POP fields. For either single or POP open field treatments, d_9_0 was always less than 22 mm, while for 6 MV or less, values of d_9_0 were less than 4 mm; D_m_a_x values can be very large (e.g., above 300 cGy) for certain treatment situations and are reduced significantly for POP treatments; for open field POP treatments, the percent reduction in D_m_a_x with each increment in beam energy above 10 MV is reduced over that seen at 10 MV or less and, possibly, this further reduction may be clinically insignificant; for open field POP treatments, changes in surface dose, d_9_0 and D_m_a_x with beam energy above 10 MV do not suggest, with regard to these specific build-up curve parameters, any obvious advantage for treatment with beam energies greater

  17. Effect of various physical parameters on surface and build-up dose for 15-MV X-rays

    International Nuclear Information System (INIS)

    Yadav, Girigesh; Yadav, R.S.; Kumar, Alok

    2010-01-01

    The purpose of this study was to find out the effect of various physical parameters on the skin and build-up doses of 15-MV photon beams. The effects of field dimensions, acrylic shadow tray, focus to-skin distance (FSD) on surface and buildup dose were determined for open, motorized 60 deg wedge (MW) and blocked fields. A 'Markus' plane parallel plate chamber was used for these measurements in an Elekta (6-15MV) linear accelerator. The surface dose for MW fields was lower than the dose for an open field, but the trend reversed for large fields and higher degree wedges. With the use of an acrylic shadow tray, the surface dose increased for all field sizes, but the increase was dominant for large fields. The surface dose for blocked fields was lower than the dose for open fields. The percentage depth dose of 10 x 10 cm 2 field at surface (PDD 0 ) for open beam were 13.89%, 11.71%, and 10.74% at 80 cm, 100 cm, and 120 cm FSD, respectively. The blocking tray increased PDD 0 of 10 x 10 cm 2 field to 26.29%, 14.01%, and 11.53%, while the motorized 60 deg wedge decreased PDD 0 to 11.32%, 9.7%, and 8.9 % at these FSDs. The maximum PDD difference seen at surface (i.e. skin) for 5x5 cm 2 , 15x15 cm 2 , and 30x30 cm 2 are 0.5%, 4.6%, and 5.6% for open field and 0.9%, 4.7%, and 7.2% for motorized 60 deg wedge field, when FSDs varied from 80 cm to 120 cm. The maximum PDD difference seen at surface for 5x5 cm 2 , 15x15 cm 2 , and 30x30 cm 2 fields are 5.6%, 22.8%, and 29.6%, respectively, for a 1.0-cm perspex-blocking tray as the FSD is changed. The maximum PDD difference was seen at the surface (i.e. skin) and this decreased with increasing depth. (author)

  18. Effect of silver sulfadiazine treat in Ⅲ-Ⅳ period pressure sores%磺胺嘧啶银治疗Ⅲ~Ⅳ期压疮的疗效观察

    Institute of Scientific and Technical Information of China (English)

    曹燕文; 顾宏华

    2015-01-01

    目的:探讨磺胺嘧啶银在压疮患者中的应用效果。方法:2012年1月~2013年10月收治住院患者124例,将其随机等分为对照组和试验组,对照组采用庆大霉素治疗压疮,试验组采用磺胺嘧啶银治疗压疮。比较两组患者的疗效。结果:试验组患者疗效优于对照组(P<0.05)。结论:对患者采用磺胺嘧啶银治疗,疗程短,治愈率高,疗效显著,符合现代伤口换药湿性愈合的理念。%Objective:To investigate the therapeutic effects of silver sulfadiazine in pressure sores .Methods:124 patients who were admitted to hospital in Jan.2012-Oct.2013.were randomly divided into control group and experimental group .The control group using gentamicin treatment of pressure sores on patients,the experimental group using silver sulfadiazine treatment .Results:The experimental group was significantly better than the control group .Conclu-sion:Patients with silver sulfadiazine treatment had some advontages,such as short course,high cure rate,a significant effect,in line with current wound dressing moist healing concept.

  19. Build-up of the silicon micro-strip detector array in ETF of HIRFL-CSR

    International Nuclear Information System (INIS)

    Wang Pengfei; Li Zhankui; Li Haixia

    2014-01-01

    Silicon micro-strip detectors have been widely used in the world-famous nuclear physics laboratories due to their better position resolution and energy resolution. Double-sided silicon micro-strip detectors with a position resolution of 0.5 mm × 0.5 mm, have been fabricated in the IMP (Institute of Modern Physics, CAS) by using microelectronics technology. These detectors have been used in the ETF (External Target Facility) of HIRFL-CSR, as ΔE detectors of the ΔE-E telescope system and the track detectors. With the help of flexibility printed circuit board (FPCB) and the integrated ASIC chips, a compact multi-channel front-end electronic board has been designed to fulfill the acquisition of the energy and position information of the Silicon micro-strip detectors. It is described in this paper that the build-up of the Silicon micro-strip detector array in ETF of HIRFL-CSR, the determination of the energy resolution of the detector units, and the energy resolution of approximately 1% obtained for 5∼9 MeV α particles in vacuum. (authors)

  20. Determination of neutron buildup factor using analytical solution of one-dimensional neutron diffusion equation in cylindrical geometry

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Julio Cesar L.; Vilhena, Marco Tullio, E-mail: julio.lombaldo@ufrgs.b, E-mail: vilhena@pq.cnpq.b [Universidade Federal do Rio Grande do Sul (DMPA/UFRGS), Porto Alegre, RS (Brazil). Dept. de Matematica Pura e Aplicada. Programa de Pos Graduacao em Matematica Aplicada; Borges, Volnei; Bodmann, Bardo Ernest, E-mail: bardo.bodmann@ufrgs.b, E-mail: borges@ufrgs.b [Universidade Federal do Rio Grande do Sul (PROMEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica

    2011-07-01

    The principal idea of this work, consist on formulate an analytical method to solved problems for diffusion of neutrons with isotropic scattering in one-dimensional cylindrical geometry. In this area were develop many works that study the same problem in different system of coordinates as well as cartesian system, nevertheless using numerical methods to solve the shielding problem. In view of good results in this works, we starting with the idea that we can represent a source in the origin of the cylindrical system by a Delta Dirac distribution, we describe the physical modeling and solved the neutron diffusion equation inside of cylinder of radius R. For the case of transport equation, the formulation of discrete ordinates S{sub N} consists in discretize the angular variables in N directions and in using a quadrature angular set for approximate the sources of scattering, where the Diffusion equation consist on S{sub 2} approximated transport equation in discrete ordinates. We solved the neutron diffusion equation with an analytical form by the finite Hankel transform. Was presented also the build-up factor for the case that we have neutron flux inside the cylinder. (author)

  1. Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages.

    Science.gov (United States)

    Mamoun, John

    2017-06-01

    Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.

  2. DC Model Cable under Polarity Inversion and Thermal Gradient: Build-Up of Design-Related Space Charge

    Directory of Open Access Journals (Sweden)

    Nugroho Adi

    2017-07-01

    Full Text Available In the field of energy transport, High-Voltage DC (HVDC technologies are booming at present due to the more flexible power converter solutions along with needs to bring electrical energy from distributed production areas to consumption sites and to strengthen large-scale energy networks. These developments go with challenges in qualifying insulating materials embedded in those systems and in the design of insulations relying on stress distribution. Our purpose in this communication is to illustrate how far the field distribution in DC insulation systems can be anticipated based on conductivity data gathered as a function of temperature and electric field. Transient currents and conductivity estimates as a function of temperature and field were recorded on miniaturized HVDC power cables with construction of 1.5 mm thick crosslinked polyethylene (XLPE insulation. Outputs of the conductivity model are compared to measured field distributions using space charge measurements techniques. It is shown that some features of the field distribution on model cables put under thermal gradient can be anticipated based on conductivity data. However, space charge build-up can induce substantial electric field strengthening when materials are not well controlled.

  3. Determination of neutron buildup factor using analytical solution of one-dimensional neutron diffusion equation in cylindrical geometry

    International Nuclear Information System (INIS)

    Fernandes, Julio Cesar L.; Vilhena, Marco Tullio; Borges, Volnei; Bodmann, Bardo Ernest

    2011-01-01

    The principal idea of this work, consist on formulate an analytical method to solved problems for diffusion of neutrons with isotropic scattering in one-dimensional cylindrical geometry. In this area were develop many works that study the same problem in different system of coordinates as well as cartesian system, nevertheless using numerical methods to solve the shielding problem. In view of good results in this works, we starting with the idea that we can represent a source in the origin of the cylindrical system by a Delta Dirac distribution, we describe the physical modeling and solved the neutron diffusion equation inside of cylinder of radius R. For the case of transport equation, the formulation of discrete ordinates S N consists in discretize the angular variables in N directions and in using a quadrature angular set for approximate the sources of scattering, where the Diffusion equation consist on S 2 approximated transport equation in discrete ordinates. We solved the neutron diffusion equation with an analytical form by the finite Hankel transform. Was presented also the build-up factor for the case that we have neutron flux inside the cylinder. (author)

  4. Pressure Sores

    Science.gov (United States)

    Pressure sores are areas of damaged skin caused by staying in one position for too long. They commonly ... wheelchair, or are unable to change your position. Pressure sores can cause serious infections, some of which are ...

  5. Vapor pressure isotope effect in 13CClF3/12CClF3 by cryogenic distillation kinetics

    International Nuclear Information System (INIS)

    Wieck, H.J.; Ishida, T.

    1975-08-01

    The vapor pressure of 13 CClF 3 relative to the vapor pressure of 12 CClF 3 was measured as a function of temperature between 169 0 and 206 0 K by using a modified Bigeleisen distillation column. The transient build-up of the isotopic concentration gradient along the length of the packed column during the start-up period was monitored by taking samples from the condenser section as a function of time. The gaseous samples were completely oxidized to carbon dioxide in the presence of a platinum catalyst and a large excess of oxygen at temperatures between 1050 and 1100 0 C. The combustion products were purified by means of gas chromatography, and the purified carbon dioxide samples were analyzed in a Nier-type isotope-ratio mass spectrometer. The data of each distillation run were reduced in the light of Cohen's theory of the kinetics of square cascade of close-separation stages. The vapor pressure isotope effect for the carbon substitution in CClF 3 at temperatures between 169 0 and 206 0 K was found to be an inverse effect and to be rather insensitive to changes in temperature. The relative vapor pressure may be expressed 1n(P'/P) = [(1.5 +- 14.1)/T 2 ] - [(0.159 +- 0.076)/T], or 1n(P'/P) = [(0.173 +- 0.098)/T] - [(0.11 +- 0.53) x 10 -3 ], where P' and P are the vapor pressures of 12 CClF 3 and 13 CClF 3 , respectively. To the first-order, the presence of chlorine isotopes would not affect the fractionation of carbon isotopes by the distillation of CClF 3

  6. Hydrogen purification by periodic adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Barg, Christian; Secchi, Argimiro R.; Trierweiler, Jorge O. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Dept. de Engenharia Quimica]. E-mail: cbarg@enq.ufrgs.br; arge@enq.ufrgs.br; jorge@enq.ufrgs.br

    2000-07-01

    The periodic adsorption processes have been widely used for industrial applications, mainly because it spends less energy than the usual gas separation processes, like the cryogenic distillation. The largest commercial application of periodic adsorption processes is the pressure swing adsorption (PSA) applied to hydrogen purification. Although its wide use in the chemical and petrochemical industry, there are no reports in the open literature about complete modeling studies of a complex commercial unit, with multiple adsorbents and multiple beds and several feed components. This study has as objective the modeling, optimization and dynamical analysis of an industrial PSA unit for hydrogen purification. (author)

  7. Intracranial Pressure

    DEFF Research Database (Denmark)

    Hvedstrup, Jeppe; Radojicic, Aleksandra; Moudrous, Walid

    2018-01-01

    OBJECTIVE: To compare a new method of noninvasive intracranial pressure (nICP) measurement with conventional lumbar puncture (LP) opening pressure. METHODS: In a prospective multicenter study, patients undergoing LP for diagnostic purposes underwent intracranial pressure measurements with HeadSen...

  8. Pressure Ulcers

    OpenAIRE

    Monfre, Jill M.

    2016-01-01

    Unrelieved pressure or friction of the skin, particularly over bony prominences, can lead to pressure ulcers, which affect up to one third of people in hospitals or community care, and one fifth of nursing home residents. Pressure ulcers are more likely in people with reduced mobility and poor skin condition, such as older people or those with vascular disease.

  9. Atmospheric Pressure During Landing

    Science.gov (United States)

    1997-01-01

    This figure shows the variation with time of pressure (dots) measured by the Pathfinder MET instrument during the landing period shown in image PIA00797. The two diamonds indicate the times of bridal cutting and 1st impact. The overall trend in the data is of pressure increasing with time. This is almost certainly due to the lander rolling downhill by roughly 10 m. The spacing of the horizontal dotted lines indicates the pressure change expected from 10 m changes in altitude. Bounces may also be visible in the data.

  10. Evolution of periodicity in periodical cicadas.

    Science.gov (United States)

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  11. Liquid return from gas pressurization of grouted waste

    International Nuclear Information System (INIS)

    Powell, W.J.; Benny, H.L.

    1994-05-01

    The ability to force pore liquids out of a simulated waste grout matrix using air pressure was measured. Specimens cured under various conditions were placed in a permeameter and subjected to increasing air pressure. The pressure was held constant for 24 hours and then stepped up until either liquid was released or 150 psi was reached. One specimen was taken to 190 psi with no liquid release. Permeability to simulated tank waste was then measured. Compressive strength was measured following these tests. This data is to assess the amount of fluid that might be released from grouted waste resulting from the buildup of radiolytically generated hydrogen and other gasses within the waste form matrix. A plot of the unconfined compressive strength versus breakthrough pressures identifies a region of ''good'' grout, which will resist liquid release

  12. Reference values and associated factors for Japanese newborns' blood pressure and pulse rate: the babies' and their parents' longitudinal observation in Suzuki Memorial Hospital on intrauterine period (BOSHI) study.

    Science.gov (United States)

    Satoh, Michihiro; Inoue, Ryusuke; Tada, Hideko; Hosaka, Miki; Metoki, Hirohito; Asayama, Kei; Murakami, Takahisa; Mano, Nariyasu; Ohkubo, Takayoshi; Yagihashi, Katsuyo; Hoshi, Kazuhiko; Suzuki, Masakuni; Imai, Yutaka

    2016-08-01

    Currently, normative means and ranges of blood pressure (BP) and pulse rates in Japanese newborns are not available. The objective of the present study was to estimate BP, pulse rate, and their distribution among Japanese newborns. Using oscillometric devices, arm or calf BP and pulse rate levels were obtained from 3148 infants born between 2007 and 2014, consecutively at Suzuki Memorial Hospital, Iwanuma, Japan. Of those, data from 2628 full-term, singleton newborns with BP measured on day 3 after birth were analyzed. Arm SBP/DBP and pulse rate in the reference group (n = 2628) were 70.5 ± 7.4/44.3 ± 6.7 mmHg and 117.3 ± 16.6 bpm, respectively. The 5-95th percentiles were 58-83 mmHg for SBP, 35-57 mmHg for DBP, and 91-145 bpm for pulse rate. Similar values were obtained from calf measurements. In multiple regression analysis, birth weight and spontaneous cephalic delivery were positively and light/deep sleep was inversely associated with higher arm SBP/DBP (P ≤ 0.04), whereas sex, Apgar score, gestational age, and mother's age did not significantly affect BP levels (P ≥ 0.06). Male sex, gestational age, spontaneous cephalic delivery, and light/deep sleep were inversely associated with higher pulse rate (P ≤ 0.02). The present study is the first to show the distributions of Asian newborns' BP levels and pulse rate. The assessment of newborns' BP levels and pulse rate should consider birth weight, gestational age after birth, and actual condition at BP measurement.

  13. A closed-form formulation for the build-up factor and absorbed energy for photons and electrons in the Compton energy range in Cartesian geometry

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Volnei; Vilhena, Marco Tullio, E-mail: borges@ufrgs.b, E-mail: vilhena@pq.cnpq.b [Universidade Federal do Rio Grande do Sul (PROMEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Fernandes, Julio Cesar Lombaldo, E-mail: julio.lombaldo@ufrgs.b [Universidade Federal do Rio Grande do Sul (DMPA/UFRGS), Porto Alegre, RS (Brazil). Dept. de Matematica Pura e Aplicada. Programa de Pos Graduacao em Matematica Aplicada

    2011-07-01

    In this work, we report on a closed-form formulation for the build-up factor and absorbed energy, in one and two dimensional Cartesian geometry for photons and electrons, in the Compton energy range. For the one-dimensional case we use the LTS{sub N} method, assuming the Klein-Nishina scattering kernel for the determination of the angular radiation intensity for photons. We apply the two-dimensional LTS{sub N} nodal solution for the averaged angular radiation evaluation for the two-dimensional case, using the Klein-Nishina kernel for photons and the Compton kernel for electrons. From the angular radiation intensity we construct a closed-form solution for the build-up factor and evaluate the absorbed energy. We present numerical simulations and comparisons against results from the literature. (author)

  14. A closed-form formulation for the build-up factor and absorbed energy for photons and electrons in the Compton energy range in Cartesian geometry

    International Nuclear Information System (INIS)

    Borges, Volnei; Vilhena, Marco Tullio; Fernandes, Julio Cesar Lombaldo

    2011-01-01

    In this work, we report on a closed-form formulation for the build-up factor and absorbed energy, in one and two dimensional Cartesian geometry for photons and electrons, in the Compton energy range. For the one-dimensional case we use the LTS N method, assuming the Klein-Nishina scattering kernel for the determination of the angular radiation intensity for photons. We apply the two-dimensional LTS N nodal solution for the averaged angular radiation evaluation for the two-dimensional case, using the Klein-Nishina kernel for photons and the Compton kernel for electrons. From the angular radiation intensity we construct a closed-form solution for the build-up factor and evaluate the absorbed energy. We present numerical simulations and comparisons against results from the literature. (author)

  15. Fast fracture of a zirconium alloy pressure tube: cause and implications

    International Nuclear Information System (INIS)

    Price, E.G.; Cheadle, B.A.

    1985-12-01

    The cause of the unstable fracture of a Zircaloy-2 pressure tube in the core of a CANDU reactor is reviewed. Failure was associated with the presence of brittle zones of zirconium hydride which developed as a result of thermal gradient induced hydrogen diffusion. Unstable fracture occurred when the partial thickness crack reached an unstable length and the crack ran 2 meters along the tube and terminated by circumferential tearing. The partial thickness defect initiated and propagated to an unstable length by delayed hydride cracking is high compared to fatigue progression and increases exponentially with temperature. Delayed hydride cracking can be prevented by reducing residual stresses to a minimum and by high standards of non-destructive testing that ensures freedom from unacceptable defects. Future prevention of fast fracture is based upon the inspection of a limited number of fuel channels for the presence of defects and for conditions which can cause hydride build-up together with the periodic removal of Zr-2.5wt% Nb tubes to monitor their condition

  16. Catheter for Cleaning Surgical Optics During Surgical Procedures: A Possible Solution for Residue Buildup and Fogging in Video Surgery.

    Science.gov (United States)

    de Abreu, Igor Renato Louro Bruno; Abrão, Fernando Conrado; Silva, Alessandra Rodrigues; Corrêa, Larissa Teresa Cirera; Younes, Riad Nain

    2015-05-01

    Currently, there is a tendency to perform surgical procedures via laparoscopic or thoracoscopic access. However, even with the impressive technological advancement in surgical materials, such as improvement in quality of monitors, light sources, and optical fibers, surgeons have to face simple problems that can greatly hinder surgery by video. One is the formation of "fog" or residue buildup on the lens, causing decreased visibility. Intracavitary techniques for cleaning surgical optics and preventing fog formation have been described; however, some of these techniques employ the use of expensive and complex devices designed solely for this purpose. Moreover, these techniques allow the cleaning of surgical optics when they becomes dirty, which does not prevent the accumulation of residue in the optics. To solve this problem we have designed a device that allows cleaning the optics with no surgical stops and prevents the fogging and residue accumulation. The objective of this study is to evaluate through experimental testing the effectiveness of a simple device that prevents the accumulation of residue and fogging of optics used in surgical procedures performed through thoracoscopic or laparoscopic access. Ex-vivo experiments were performed simulating the conditions of residue presence in surgical optics during a video surgery. The experiment consists in immersing the optics and catheter set connected to the IV line with crystalloid solution in three types of materials: blood, blood plus fat solution, and 200 mL of distilled water and 1 vial of methylene blue. The optics coupled to the device were immersed in 200 mL of each type of residue, repeating each immersion 10 times for each distinct residue for both thirty and zero degrees optics, totaling 420 experiments. A success rate of 98.1% was observed after the experiments, in these cases the device was able to clean and prevent the residue accumulation in the optics.

  17. On the relative role of meridional convergence and downwelling motion during the heat buildup leading to El Niño events

    Science.gov (United States)

    Ballester, Joan; Bordoni, Simona; Petrova, Desislava; Rodó, Xavier

    2015-04-01

    Despite steady progress in the understanding of El Niño-Southern Oscillation (ENSO) in the past decades, questions remain on the exact mechanisms leading to the onset of El Niño (EN) events. Several authors have highlighted how the subsurface heat buildup in the western tropical Pacific and the recharged phase in equatorial heat content are intrinsic elements of ENSO variability, leading to those changes in zonal wind stress, sea surface temperature and thermocline tilt that characterize the growing and mature phases of EN. Here we use an ensemble of ocean and atmosphere assimilation products to identify the mechanisms contributing to the heat buildup that precedes EN events by about 18-24 months on average. Anomalous equatorward subsurface mass convergence due to meridional Sverdrup transport is found to be an important mechanism of thermocline deepening near and to the east of the dateline. In the warm pool, instead, surface horizontal convergence and downwelling motion have a leading role in subsurface warming, since equatorward mass convergence is weaker and counterbalanced by subsurface zonal divergence. The picture emerging from our results highlights the complexity of the three dimensional dynamic and thermodynamic structure of the tropical Pacific during the heat buildup leading to EN events.

  18. A polynomial–based function approach to point isotropic gamma-ray buildup factor data in double layered spherical shield of water and lead

    Directory of Open Access Journals (Sweden)

    M. H. Alamatsaz

    2014-03-01

    Full Text Available As the input of MCNP code (Monte Carlo N - Particle code system, a monoenergetic and isotropic point source with the energy rangeg from 0.3 to 10 MeV was placed at the center of a spherical material surrounded by another one. The first shielding material was water and the second one was lead. The total thickness of the shield varied between 2 to 10 mfp. Then, using the output of MCNCP, exposure build up factor was calculated. The MCNP computed data were analyzed by plotting the buildup factor as a function of each independent variable (energy, first material thickness and second material thickness and observing the trends. Based on the trends, we examined many different expressions with different number of constants. By MINUIT the FORTRAN program, the constants were calculated, which gave the best agreement between the MCNP-computed exposure buildup factors and those obtained by the formula. At last, we developed a polynomial formula with 11 constants that reproduced exposure buildup factor with a relative error below 2% (in comparison with the MCNP result.

  19. Monte Carlo correction factors for a Farmer 0.6 cm3 ion chamber dose measurement in the build-up region of the 6 MV clinical beam

    International Nuclear Information System (INIS)

    Pena, J; Sanchez-Doblado, F; Capote, R; Terron, J A; Gomez, F

    2006-01-01

    Reference dosimetry of photon fields is a well-established subject and currently available protocols (such as the IAEA TRS-398 and AAPM TG-51) provide methods for converting the ionization chamber (IC) reading into dose to water, provided reference conditions of charged particle equilibrium (CPE) are fulfilled. But these protocols cannot deal with the build-up region, where the lack of CPE limits the applicability of the cavity theorems and so the chamber correction factors become depth dependent. By explicitly including the IC geometry in the Monte Carlo simulations, depth-dependent dose correction factors are calculated for a PTW 30001 0.6 cm 3 ion chamber in the build-up region of the 6 MV photon beam. The corrected percentage depth dose (PDD) agrees within 2% with that measured using the NACP 02 plane-parallel ion chamber in the build-up region at depths greater than 0.4 cm, where the Farmer chamber wall reaches the phantom surface

  20. Measurement of air kerma rates for 6- to 7-MeV high-energy gamma-ray field by ionisation chamber and build-up plate.

    Science.gov (United States)

    Kowatari, Munehiko; Tanimura, Yoshihiko; Tsutsumi, Masahiro

    2014-12-01

    The 6- to 7-MeV high-energy gamma-ray calibration field by the (19)F(p, αγ)(16)O reaction is to be served at the Japan Atomic Energy Agency. For the determination of air kerma rates using an ionisation chamber in the 6- to 7-MeV high-energy gamma-ray field, the establishment of the charged particle equilibrium must be achieved during measurement. In addition to measurement of air kerma rates by the ionisation chamber with a thick build-up cap, measurement using the ionisation chamber and a build-up plate (BUP) was attempted, in order to directly determine air kerma rates under the condition of regular calibration for ordinary survey meters and personal dosemeters. Before measurements, Monte Carlo calculations were made to find the optimum arrangement of BUP in front of the ionisation chamber so that the charged particle equilibrium could be well established. Measured results imply that air kerma rates for the 6- to 7-MeV high-energy gamma-ray field could be directly determined under the appropriate condition using an ionisation chamber coupled with build-up materials. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Comparison of build-up region doses in oblique tangential 6 MV photon beams calculated by AAA and CCC algorithms in breast Rando phantom

    Science.gov (United States)

    Masunun, P.; Tangboonduangjit, P.; Dumrongkijudom, N.

    2016-03-01

    The purpose of this study is to compare the build-up region doses on breast Rando phantom surface with the bolus covered, the doses in breast Rando phantom and also the doses in a lung that is the heterogeneous region by two algorithms. The AAA in Eclipse TPS and the collapsed cone convolution algorithm in Pinnacle treatment planning system were used to plan in tangential field technique with 6 MV photon beam at 200 cGy total doses in Breast Rando phantom with bolus covered (5 mm and 10 mm). TLDs were calibrated with Cobalt-60 and used to measure the doses in irradiation process. The results in treatment planning show that the doses in build-up region and the doses in breast phantom were closely matched in both algorithms which are less than 2% differences. However, overestimate of doses in a lung (L2) were found in AAA with 13.78% and 6.06% differences at 5 mm and 10 mm bolus thickness, respectively when compared with CCC algorithm. The TLD measurements show the underestimate in buildup region and in breast phantom but the doses in a lung (L2) were overestimated when compared with the doses in the two plannings at both thicknesses of the bolus.

  2. Pressure Ulcers Surveillance Report

    Directory of Open Access Journals (Sweden)

    Zehra Esin Gencer

    2015-04-01

    Full Text Available Objective: Pressure ulcer is a chronic wound. It reduces the quality of life of the elderly and individuals with restricted range of motion. It prolongs hospital stay and increases the risk of complications. The cost is quite high. Preventive actions for the prevention of pressure ulcers should be developed. Planning protocols and standards of care are among the main targets. Material and Method: Research was conducted in one-year period between 2012 May and 2013 May on patients who were followed up in Akdeniz University Hospital clinics and intensive care unit with pressure ulcers. The research population consisted of 569 patients. Patient data were recorded in SPSS 16 for Windows program. Statistical analyzes were performed with retrospective methods. The demographic characteristics of patients with pressure ulcers were analyzed as frequency and descriptive statistics. Prevalence and incidence of one year were calculated. Results: Of the patients, 58% were males, 42% were females. Of the patients, 36% were in the age range of 61-80 years, and their average length of stay was 42,9 days. Of the patients, 70% were at stage 2 and 3. In 15% of patients pressure ulcers occurred on the first day of hospitalization. Pressure ulcers were developed between days 2 and 10 in 59% of the patients. Prevalence rate was 2.5%, the incidence was 1.9%, the prevalence rate was 5.9% in the intensive care unit. Conclusion: It is easier to prevent pressure ulcers than treating.

  3. Mississippian carbonate buildups and development of cool-waterlike carbonate platforms in the Illinois Basin, Midcontinent U.S.A.

    Science.gov (United States)

    Lasemi, Z.; Norby, R.D.; Utgaard, J.E.; Ferry, W.R.; Cuffey, R.J.; Dever, G.R.

    2005-01-01

    Numerous biohermal buildups occur in Mississippian (Lower Carboniferous) strata in the Illinois Basin and adjacent regions. They developed as mud mounds, biodetrital calcisiltite mounds, and bryozoan frame thickets (fenestrate-frame coquina or rudstone) during the Kinderhookian and early Meramecian (Tournaisian and early Visean), and as microbial mud mounds, microbial- serpulidbryozoanboundstones, and solenoporoid (red algal) boundstones during the Chesterian (late Visean and Serpukhovian). True Waulsortian mounds did not develop in the Illinois Basin, but echinoderm (primarily crinoids)-bryozoan carbonate banks and bryozoan frame thickets generally occupied the same niche during the Kinderhookian-early Meramecian. Nutrient availability and the resulting increase in the productivity of echinoderms and bryozoans were apparently detrimental to Waulsortian mound development. Deposition of crinoidal-bryozoan carbonates during the Kinderhookian-Osagean initially occurred on a ramp setting that later evolved into a platform with a relatively steep margin through sediment aggradation and progradation. By mid-Osagean-early Meramecian, two such platforms, namely the Burlington Shelf and the Ullin Platform, developed adjacent to a deep, initially starved basin. Sedimentologic and petrographic characteristics of the Kinderhookian-earliest Meramecian carbonates resemble the modern cool-water Heterozoan Association. This is in contrast with post-earliest Meramecian carbonates, which are typically oolitic and peloidal with common peri tidal facies. The post-earliest Meramecian carbonates, therefore, resemble those of the warm-water Photozoan Association. The prevalence of Heterozoan carbonates in the Illinois Basin correlates with a rapid increase in the rate of subsidence and a major second-order eustatic sea-level rise that resulted in deep-water starved basins at this time. In the starved Illinois Basin, deposition was initially limited to a thin phosphatic shale that was

  4. Modeling steam pressure under martian lava flows

    Science.gov (United States)

    Dundas, Colin M.; Keszthelyi, Laszlo P.

    2013-01-01

    Rootless cones on Mars are a valuable indicator of past interactions between lava and water. However, the details of the lava–water interactions are not fully understood, limiting the ability to use these features to infer new information about past water on Mars. We have developed a model for the pressurization of a dry layer of porous regolith by melting and boiling ground ice in the shallow subsurface. This model builds on previous models of lava cooling and melting of subsurface ice. We find that for reasonable regolith properties and ice depths of decimeters, explosive pressures can be reached. However, the energy stored within such lags is insufficient to excavate thick flows unless they draw steam from a broader region than the local eruption site. These results indicate that lag pressurization can drive rootless cone formation under favorable circumstances, but in other instances molten fuel–coolant interactions are probably required. We use the model results to consider a range of scenarios for rootless cone formation in Athabasca Valles. Pressure buildup by melting and boiling ice under a desiccated lag is possible in some locations, consistent with the expected distribution of ice implanted from atmospheric water vapor. However, it is uncertain whether such ice has existed in the vicinity of Athabasca Valles in recent history. Plausible alternative sources include surface snow or an aqueous flood shortly before the emplacement of the lava flow.

  5. Pressure transducers

    International Nuclear Information System (INIS)

    Gomes, A.V.

    1975-01-01

    Strain gauges pressure transducers types are presented. Models, characteristics and calibration procedures were also analysed. Initially, a theoretical study was accomplished to evaluate metallic alloys behavior on sensing elements manufacturing, and diaphragm was used as deflecting elements. Electrical models for potenciometric transducers were proposed at the beginning and subsequently comproved according our experiments. Concerning bridge transducers, existing models confirmed the conditions of linearity and sensitivity related to the electrical signal. All the work done was of help on the calibration field and pressure measurements employing unbounded strain gauge pressure transducers

  6. Peer Pressure

    Science.gov (United States)

    ... for: Teens Dealing With Bullying Emotional Intelligence Sexual Harassment and Sexual Bullying Coping With Stressful Situations Prom Pressure What Stresses You Out About School? Virginity: A Very Personal Decision Stress & Coping Center ...

  7. Periodicity of the stable isotopes

    CERN Document Server

    Boeyens, J C A

    2003-01-01

    It is demonstrated that all stable (non-radioactive) isotopes are formally interrelated as the products of systematically adding alpha particles to four elementary units. The region of stability against radioactive decay is shown to obey a general trend based on number theory and contains the periodic law of the elements as a special case. This general law restricts the number of what may be considered as natural elements to 100 and is based on a proton:neutron ratio that matches the golden ratio, characteristic of biological and crystal growth structures. Different forms of the periodic table inferred at other proton:neutron ratios indicate that the electronic configuration of atoms is variable and may be a function of environmental pressure. Cosmic consequences of this postulate are examined. (author)

  8. Fracture Resistance of Endodontically Treated Teeth Restored with 2 Different Fiber-reinforced Composite and 2 Conventional Composite Resin Core Buildup Materials: An In Vitro Study.

    Science.gov (United States)

    Eapen, Ashly Mary; Amirtharaj, L Vijay; Sanjeev, Kavitha; Mahalaxmi, Sekar

    2017-09-01

    The purpose of this in vitro study was to comparatively evaluate the fracture resistance of endodontically treated teeth restored with 2 fiber-reinforced composite resins and 2 conventional composite resin core buildup materials. Sixty noncarious unrestored human maxillary premolars were collected, endodontically treated (except group 1, negative control), and randomly divided into 5 groups (n = 10). Group 2 was the positive control. The remaining 40 prepared teeth were restored with various direct core buildup materials as follows: group 3 teeth were restored with dual-cure composite resin, group 4 with posterior composite resin, group 5 with fiber-reinforced composite resin, and group 6 with short fiber-reinforced composite resin. Fracture strength testing was performed using a universal testing machine. The results were statistically analyzed by 1-way analysis of variance and the post hoc Tukey test. Fracture patterns for each sample were also examined under a light microscope to determine the level of fractures. The mean fracture resistance values (in newtons) were obtained as group 1 > group 6 > group 4 > group 3 > group 5 > group 2. Group 6 showed the highest mean fracture resistance value, which was significantly higher than the other experimental groups, and all the fractures occurred at the level of enamel. Within the limitations of this study, a short fiber-reinforced composite can be used as a direct core buildup material that can effectively resist heavy occlusal forces against fracture and may reinforce the remaining tooth structure in endodontically treated teeth. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  9. Build-up and wash-off dynamics of atmospherically derived Cu, Pb, Zn and TSS in stormwater runoff as a function of meteorological characteristics.

    Science.gov (United States)

    Murphy, Louise U; Cochrane, Thomas A; O'Sullivan, Aisling

    2015-03-01

    Atmospheric pollutants deposited on impermeable surfaces can be an important source of pollutants to stormwater runoff; however, modelling atmospheric pollutant loads in runoff has rarely been done, because of the challenges and uncertainties in monitoring their contribution. To overcome this, impermeable concrete boards (≈ 1m(2)) were deployed for 11 months in different locations within an urban area (industrial, residential and airside) throughout Christchurch, New Zealand, to capture spatially distributed atmospheric deposition loads in runoff over varying meteorological conditions. Runoff was analysed for total and dissolved Cu, Zn, Pb, and total suspended solids (TSS). Mixed-effect regression models were developed to simulate atmospheric pollutant loads in stormwater runoff. In addition, the models were used to explain the influence of different meteorological characteristics (e.g. antecedent dry days and rain depth) on pollutant build-up and wash-off dynamics. The models predicted approximately 53% to 69% of the variation in pollutant loads and were successful in predicting pollutant-load trends over time which can be useful for general stormwater planning processes. Results from the models illustrated the importance of antecedent dry days on pollutant build-up. Furthermore, results indicated that peak rainfall intensity and rain duration had a significant relationship with TSS and total Pb, whereas, rain depth had a significant relationship with total Cu and total Zn. This suggested that the pollutant speciation phase plays an important role in surface wash-off. Rain intensity and duration had a greater influence when the pollutants were predominantly in their particulate phase. Conversely, rain depth exerted a greater influence when a high fraction of the pollutants were predominantly in their dissolved phase. For all pollutants, the models were represented by a log-arctan relationship for pollutant build-up and a log-log relationship for pollutant wash

  10. The Periodic Pyramid

    Science.gov (United States)

    Hennigan, Jennifer N.; Grubbs, W. Tandy

    2013-01-01

    The chemical elements present in the modern periodic table are arranged in terms of atomic numbers and chemical periodicity. Periodicity arises from quantum mechanical limitations on how many electrons can occupy various shells and subshells of an atom. The shell model of the atom predicts that a maximum of 2, 8, 18, and 32 electrons can occupy…

  11. Book Reviews in Periodicals.

    Science.gov (United States)

    Ettelt, Harold J.

    All recent issues of periodicals found which contain indexed book reviews are listed in this compilation from Drake Memorial Library at the New York State University at Brockport. The periodicals are listed by 29 subject headings in this informal guide designed to be used at Drake Library. The number of reviews in the periodical in a recent year…

  12. Adaptive management for subsurface pressure and plume control in application to geological CO2 storage

    Science.gov (United States)

    Gonzalez-Nicolas, A.; Cihan, A.; Birkholzer, J. T.; Petrusak, R.; Zhou, Q.; Riestenberg, D. E.; Trautz, R. C.; Godec, M.

    2016-12-01

    Industrial-scale injection of CO2 into the subsurface can cause reservoir pressure increases that must be properly controlled to prevent any potential environmental impact. Excessive pressure buildup in reservoir may result in ground water contamination stemming from leakage through conductive pathways, such as improperly plugged abandoned wells or distant faults, and the potential for fault reactivation and possibly seal breaching. Brine extraction is a viable approach for managing formation pressure, effective stress, and plume movement during industrial-scale CO2 injection projects. The main objectives of this study are to investigate suitable different pressure management strategies involving active brine extraction and passive pressure relief wells. Adaptive optimized management of CO2 storage projects utilizes the advanced automated optimization algorithms and suitable process models. The adaptive management integrates monitoring, forward modeling, inversion modeling and optimization through an iterative process. In this study, we employ an adaptive framework to understand primarily the effects of initial site characterization and frequency of the model update (calibration) and optimization calculations for controlling extraction rates based on the monitoring data on the accuracy and the success of the management without violating pressure buildup constraints in the subsurface reservoir system. We will present results of applying the adaptive framework to test appropriateness of different management strategies for a realistic field injection project.

  13. New method of analyzing well tests in fractured wells using sandface pressure and rate data

    Energy Technology Data Exchange (ETDEWEB)

    Osman, M.; Almehaideb, R.; Abou-Kassem, J. [U.A.E. University, Al-Ain (United Arab Emirates)

    1998-05-01

    Analysis of variable flow rate tests has been of special interest recently because in many cases it is impractical to keep a flow rate constant long enough to perform a drawdown test. Further, in many other drawdown and buildup tests, the early data were influenced by wellbore storage effects, and the duration of these effects could be quite long for low-permeability reservoirs. This paper presents a mathematical model which describes drawdown and buildup tests in hydraulically fractured wells. This new method uses a specialized plot approach to analyze the linear flow data and combines it with the superposition of constant-rate solution method for the analysis of psuedoradial flow data. It does not require prior knowledge of the fracture type (uniform-flux or infinite-conductivity); in fact it predicts the fracture type. This method is useful for the analysis of simultaneously measured downhole pressure and sandface rate data. 12 refs., 11 figs., 3 tabs.

  14. Laguna Verde annulus pressurization loads evaluation

    International Nuclear Information System (INIS)

    Castaneda, M. A.; Cruz, M. A.; Cardenas, J. B.; Vargas, A.; Cruz, H. J.; Mercado, J. J.

    2010-10-01

    Annulus pressurization, jet impingement, pipe whip restraint and jet thrust are phenomena related to postulated pipe ruptures. A postulated pipe rupture at the weld between recirculation, or feedwater piping and a reactor nozzle safe end, will lead to a high flow rate of flashing water/steam mixture into the annulus between the reactor pressure vessel and the biological shield wall. The total effect of the vessel and pipe inventory blowdown from the break being postulated must be accounted for in the evaluation. A recirculation line break will give rise to an angular dependent short term pressure differential around the vessel, followed by a longer term pressure buildup in the annulus. A recirculation line postulated rupture may not produce worst case conditions and reference to time intervals for only the recirculation break should be treated superficially. A postulated rupture of the feedwater piping may produce the extreme case for determining: 1) the shield wall and reactor vessel to pedestal interactions, 2) loading on the reactor vessel internals, or 3) responses for the balance of piping attached to the vessel. Recently it was identified a potential issue regarding the criteria used to determine which cases were evaluated for Annulus Pressurization (A P) loads for new loads plants. The original A P loads methodology in the late 1970 and early 1980 years separated the mass/energy release calculation from the structural response calculation based on the implicit assumption that the maximum overall mass/energy release will result in maximizing the structural response and corresponding stresses on the reactor pressure vessel, internals, and containment structures. This process did not consider the dynamic response in the primary and secondary safety related structures, components and equipment. Consequently, the A P loads used as input for design adequacy evaluations of Nuclear Steam Supply System safety related components for new loads plants might have

  15. Lepton contamination and photon scatter produced by open field 18 MV X-ray beams in the build-up region

    International Nuclear Information System (INIS)

    Butson, M.J.; Cheung Tsang; Yu, P.K.N.

    2002-01-01

    18 MV X-ray beams used in radiotherapy have skin sparing properties as they produce a dose build-up effect whereby a smaller dose is delivered to the skin compared to dose at depth. Experimental results have shown that variations in the build-up dose significantly contribute to lepton contamination produced outside of the patient or the phantom in question. Monte Carlo simulations of 18 MV X-ray beams show that the surface dose contribution from in-phantom scatter alone is approximately 6% of the maximum dose. The contribution to dose from lepton contamination is found by comparison of Monte Carlo phantom photon scatter dose only and experimental data. Results show that the percentage contributions to dose from lepton contamination are approximately, 65%, 90% of dose at 0.05 mm (basal cell layer), 52%, 79% at 1 mm depth (dermal layer) and 15%, 26% at 10 mm depth (subcutaneous tissue) for 10 cmx10 cm 2 and 40 cmx40 cm 2 fields, respectively

  16. Lepton contamination and photon scatter produced by open field 18 MV X-ray beams in the build-up region

    Energy Technology Data Exchange (ETDEWEB)

    Butson, M.J. E-mail: mbutson@guessmail.com; Cheung Tsang; Yu, P.K.N

    2002-04-01

    18 MV X-ray beams used in radiotherapy have skin sparing properties as they produce a dose build-up effect whereby a smaller dose is delivered to the skin compared to dose at depth. Experimental results have shown that variations in the build-up dose significantly contribute to lepton contamination produced outside of the patient or the phantom in question. Monte Carlo simulations of 18 MV X-ray beams show that the surface dose contribution from in-phantom scatter alone is approximately 6% of the maximum dose. The contribution to dose from lepton contamination is found by comparison of Monte Carlo phantom photon scatter dose only and experimental data. Results show that the percentage contributions to dose from lepton contamination are approximately, 65%, 90% of dose at 0.05 mm (basal cell layer), 52%, 79% at 1 mm depth (dermal layer) and 15%, 26% at 10 mm depth (subcutaneous tissue) for 10 cmx10 cm{sup 2} and 40 cmx40 cm{sup 2} fields, respectively.

  17. Effects of internal and external scatter on the build-up characteristics of Monte Carlo calculated absorbed dose for electron irradiation

    International Nuclear Information System (INIS)

    Lin, H.; Wu, DS.; Wu, AD.

    2005-01-01

    The effects of internal and external scatter on surface, build-up and depth dose characteristics simulated by Monte Carlo code EGSnrc for varying field size and SSD for a 10 MeV monoenergetic electron beam with and without an accelerator model are extensively studied in this paper. In particular, sub-millimetre surface PDD was investigated. The percentage depth doses affected significantly by the external scatter show a larger build-up dose. A forward shifted Dmax depth and a sharper fall-off region compared to PDDs with only internal scatter considered. The surface dose with both internal and external scatter shows a marked decrease at 110 cm SSD, and then slight further changes with the increasing SSD since few external scattered particles from accelerator model can reach the phantom for large SSDs. The sharp PDD increase for the 5 cm x 5 cm field compared to other fields seen when only internal scatter is considered is significantly less when external scatter is also present. The effect of external scatter on surface PDD is more pronounced for large fields than small fields (5 cm x 5 cm field)

  18. Development of a fibre-optic dosemeter to measure the skin dose and percentage depth dose in the build-up region of therapeutic photon beams

    International Nuclear Information System (INIS)

    Kim, K. A.; Yoo, W. J.; Jang, K. W.; Moon, J.; Han, K. T.; Jeon, D.; Park, J. Y.; Cha, E. J.; Lee, B.

    2013-01-01

    In this study, a fibre-optic dosemeter (FOD) using an organic scintillator with a diameter of 0.5 mm for photon-beam therapy dosimetry was fabricated. The fabricated dosemeter has many advantages, including water equivalence, high spatial resolution, remote sensing and real-time measurement. The scintillating light generated from an organic-dosemeter probe embedded in a solid-water stack phantom is guided to a photomultiplier tube and an electrometer via 20 m of plastic optical fibre. Using this FOD, the skin dose and the percentage depth dose in the build-up region according to the depths of a solid-water stack phantom are measured with 6- and 15-MV photon-beam energies with field sizes of 10310 and 20320 cm 2 , respectively. The results are compared with those measured using conventional dosimetry films. It is expected that the proposed FOD can be effectively used in radiotherapy dosimetry for accurate measurement of the skin dose and the depth dose distribution in the build-up region due to its high spatial resolution. (authors)

  19. Suspension-firing of wood with coal ash addition: Probe measurements of ash deposit build-up at Avedøre Power Plant (AVV2)

    DEFF Research Database (Denmark)

    Shafique Bashir, Muhammad; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood-firing. Investigat...... to the gas phase as HCl(g). Effect of boiler operational parameters on gas emissions has also been investigated.......This report is about full-scale probe measurements of deposit build-up and removal conducted at the Avedøreværket Unit 2, a 800 MWth suspension boiler, firing wood and natural gas with the addition of coal ash. Coal ash was used as an additive to capture potassium (K) from wood...... and boiler load on ash deposition propensity was investigated. Results of ash deposition propensity showed increasing trend with increasing flue gas temperature. Video monitoring revealed that the deposits formed were not sticky and could be easily removed, and even at very high flue gas temperatures (> 1350...

  20. Improvement of gamma-ray Sn transport calculations including coherent and incoherent scatterings and secondary sources of bremsstrahlung and fluorescence: Determination of gamma-ray buildup factors

    International Nuclear Information System (INIS)

    Kitsos, S.; Diop, C.M.; Assad, A.; Nimal, J.C.; Ridoux, P.

    1996-01-01

    Improvements of gamma-ray transport calculations in S n codes aim at taking into account the bound-electron effect of Compton scattering (incoherent), coherent scattering (Rayleigh), and secondary sources of bremsstrahlung and fluorescence. A computation scheme was developed to take into account these phenomena by modifying the angular and energy transfer matrices, and no modification in the transport code has been made. The incoherent and coherent scatterings as well as the fluorescence sources can be strictly treated by the transfer matrix change. For bremsstrahlung sources, this is possible if one can neglect the charged particles path as they pass through the matter (electrons and positrons) and is applicable for the energy range of interest for us (below 10 MeV). These improvements have been reported on the kernel attenuation codes by the calculation of new buildup factors. The gamma-ray buildup factors have been carried out for 25 natural elements up to 30 mean free paths in the energy range between 15 keV and 10 MeV

  1. Painful menstrual periods

    Science.gov (United States)

    Menstruation - painful; Dysmenorrhea; Periods - painful; Cramps - menstrual; Menstrual cramps ... into two groups, depending on the cause: Primary dysmenorrhea Secondary dysmenorrhea Primary dysmenorrhea is menstrual pain that ...

  2. Middle Helladic Period

    DEFF Research Database (Denmark)

    Sarri, Kalliopi

    1999-01-01

    and their quality was improved considerably toward the end of this period. The profound cultural innovations of the Middle Helladic period were initially interpreted as a result of violent population movement and troubles provoked by the coming of the first Indo-European races. However, this matter does no more...... Helladic period is considered as a period of economic and social decline it was the time during which the mainland features merged with the insular influence, that is all the Aegean elements which led to the creation of the Mycenaean civilization were mixed in a creative way....

  3. On some periodicity effects

    DEFF Research Database (Denmark)

    Sorokin, Sergey V.

    2015-01-01

    The talk is concerned with the modelling of wave propagation in and vibration of periodic elastic structures. Although analysis of wave-guide properties of infinite periodic structures is a well establish research subject, some issues have not yet been fully addressed in the literature. The aim o...

  4. The Living Periodic Table

    Science.gov (United States)

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  5. A random-walk model for pore pressure accumulation in marine soils

    DEFF Research Database (Denmark)

    Sumer, B. Mutlu; Cheng, Niang-Sheng

    1999-01-01

    A numerical random-walk model has been developed for the pore-water pressure. The model is based on the analogy between the variation of the pore pressure and the diffusion process of any passive quantity such as concentration. The pore pressure in the former process is analogous...... to the concentration in the latter. In the simulation, particles are released in the soil, and followed as they travel through the statistical field variables. The model has been validated (1) against the Terzaghi consolidation process, and (2) against the process where the pore pressure builds up under progressive...... waves. The model will apparently enable the researcher to handle complex geometries (such as a pipeline buried in a soil) relatively easily. Early results with regard to the latter example, namely the buildup of pore pressure around a buried pipeline subject to a progressive wave, are encouraging....

  6. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    International Nuclear Information System (INIS)

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R.; Hong-Nian Jow

    1996-07-01

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm 3 thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm 3 active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response

  7. Periods and Nori motives

    CERN Document Server

    Huber, Annette

    2017-01-01

    This book casts the theory of periods of algebraic varieties in the natural setting of Madhav Nori’s abelian category of mixed motives. It develops Nori’s approach to mixed motives from scratch, thereby filling an important gap in the literature, and then explains the connection of mixed motives to periods, including a detailed account of the theory of period numbers in the sense of Kontsevich-Zagier and their structural properties. Period numbers are central to number theory and algebraic geometry, and also play an important role in other fields such as mathematical physics. There are long-standing conjectures about their transcendence properties, best understood in the language of cohomology of algebraic varieties or, more generally, motives. Readers of this book will discover that Nori’s unconditional construction of an abelian category of motives (over fields embeddable into the complex numbers) is particularly well suited for this purpose. Notably, Kontsevich's formal period algebra represents a to...

  8. Build-up of Red Blood Cells in Refuelling Bar-Tailed Godwits in Relation to Individual Migratory Quality

    NARCIS (Netherlands)

    Piersma, Theunis; Everaarts, Jan M.; Jukema, Joop

    1996-01-01

    We examined hemoglobin concentration, hematocrit and mean cell hemoglobin concentration (MCHbC) in Bar-tailed Godwits Limosa lapponica during the latter half of their staging period in May in the Wadden Sea of The Netherlands. Here they recover from a 4,000-5,000 km long flight from West African

  9. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation

    International Nuclear Information System (INIS)

    Schranz, C; Möller, K; Becher, T; Schädler, D; Weiler, N

    2014-01-01

    Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (p I ), inspiration and expiration time (t I , t E ) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal p I and adequate t E can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's ‘optimized’ settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end

  10. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation.

    Science.gov (United States)

    Schranz, C; Becher, T; Schädler, D; Weiler, N; Möller, K

    2014-03-01

    Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (pI), inspiration and expiration time (tI, tE) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal pI and adequate tE can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's 'optimized' settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory pressure.

  11. Mean-periodic functions

    Directory of Open Access Journals (Sweden)

    Carlos A. Berenstein

    1980-01-01

    Full Text Available We show that any mean-periodic function f can be represented in terms of exponential-polynomial solutions of the same convolution equation f satisfies, i.e., u∗f=0(μ∈E′(ℝn. This extends to n-variables the work of L. Schwartz on mean-periodicity and also extends L. Ehrenpreis' work on partial differential equations with constant coefficients to arbitrary convolutors. We also answer a number of open questions about mean-periodic functions of one variable. The basic ingredient is our work on interpolation by entire functions in one and several complex variables.

  12. Build-up and surface dose measurements on phantoms using micro-MOSFET in 6 and 10 MV x-ray beams and comparisons with Monte Carlo calculations

    International Nuclear Information System (INIS)

    Xiang, Hong F.; Song, Jun S.; Chin, David W. H.; Cormack, Robert A.; Tishler, Roy B.; Makrigiorgos, G. Mike; Court, Laurence E.; Chin, Lee M.

    2007-01-01

    This work is intended to investigate the application and accuracy of micro-MOSFET for superficial dose measurement under clinically used MV x-ray beams. Dose response of micro-MOSFET in the build-up region and on surface under MV x-ray beams were measured and compared to Monte Carlo calculations. First, percentage-depth-doses were measured with micro-MOSFET under 6 and 10 MV beams of normal incidence onto a flat solid water phantom. Micro-MOSFET data were compared with the measurements from a parallel plate ionization chamber and Monte Carlo dose calculation in the build-up region. Then, percentage-depth-doses were measured for oblique beams at 0 deg. - 80 deg. onto the flat solid water phantom with micro-MOSFET placed at depths of 2 cm, 1 cm, and 2 mm below the surface. Measurements were compared to Monte Carlo calculations under these settings. Finally, measurements were performed with micro-MOSFET embedded in the first 1 mm layer of bolus placed on a flat phantom and a curved phantom of semi-cylindrical shape. Results were compared to superficial dose calculated from Monte Carlo for a 2 mm thin layer that extends from the surface to a depth of 2 mm. Results were (1) Comparison of measurements with MC calculation in the build-up region showed that micro-MOSFET has a water-equivalence thickness (WET) of 0.87 mm for 6 MV beam and 0.99 mm for 10 MV beam from the flat side, and a WET of 0.72 mm for 6 MV beam and 0.76 mm for 10 MV beam from the epoxy side. (2) For normal beam incidences, percentage depth dose agree within 3%-5% among micro-MOSFET measurements, parallel-plate ionization chamber measurements, and MC calculations. (3) For oblique incidence on the flat phantom with micro-MOSFET placed at depths of 2 cm, 1 cm, and 2 mm, measurements were consistent with MC calculations within a typical uncertainty of 3%-5%. (4) For oblique incidence on the flat phantom and a curved-surface phantom, measurements with micro-MOSFET placed at 1.0 mm agrees with the MC

  13. Painful periods (dysmenorrhea) (image)

    Science.gov (United States)

    Primary dysmenorrhea is a normal cramping of the lower abdomen caused by hormone-induced uterine contractions before the period. Secondary dysmenorrhea may be caused by abnormal conditions such as ...

  14. Vaginal bleeding between periods

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003156.htm Vaginal bleeding between periods To use the sharing features ... this page, please enable JavaScript. This article discusses vaginal bleeding that occurs between a woman's monthly menstrual ...

  15. Super periodic potential

    Science.gov (United States)

    Hasan, Mohammd; Mandal, Bhabani Prasad

    2018-04-01

    In this paper we introduce the concept of super periodic potential (SPP) of arbitrary order n, n ∈I+, in one dimension. General theory of wave propagation through SPP of order n is presented and the reflection and transmission coefficients are derived in their closed analytical form by transfer matrix formulation. We present scattering features of super periodic rectangular potential and super periodic delta potential as special cases of SPP. It is found that the symmetric self-similarity is the special case of super periodicity. Thus by identifying a symmetric fractal potential as special cases of SPP, one can obtain the tunnelling amplitude for a particle from such fractal potential. By using the formalism of SPP we obtain the close form expression of tunnelling amplitude of a particle for general Cantor and Smith-Volterra-Cantor potentials.

  16. Establishing contract periods

    International Nuclear Information System (INIS)

    Huffman, F.C.

    1978-01-01

    The lead time for executing the Adjustable Fixed-Commitment (AFC) contract and exceptions which may be considered are discussed. The initial delivery period is also discussed. Delays, deferrals, and schedule adjustment charges are finally considered

  17. The Periodic Table CD.

    Science.gov (United States)

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  18. Setting the Periodic Table.

    Science.gov (United States)

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  19. Supersymmetrically transformed periodic potentials

    OpenAIRE

    C, David J. Fernandez

    2003-01-01

    The higher order supersymmetric partners of a stationary periodic potential are studied. The transformation functions associated to the band edges do not change the spectral structure. However, when the transformation is implemented for factorization energies inside of the forbidden bands, the final potential will have again the initial band structure but it can have bound states encrusted into the gaps, giving place to localized periodicity defects.

  20. Thyrotoxic periodic paralysis

    OpenAIRE

    Rojith Karandode Balakrishnan; Suresh Rama Chandran; Geetha Thirumalnesan; Nedumaran Doraisamy

    2011-01-01

    This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recove...

  1. Acoustic Radiation Pressure

    Science.gov (United States)

    Cantrell, John H.

    2018-01-01

    The theoretical foundation of acoustic radiation pressure in plane wave beams is reexamined. It is shown from finite deformation theory and the Boltzmann-Ehrenfest Adiabatic Principle that the Brillouin stress tensor (BST) is the radiation stress in Lagrangian coordinates (not Eulerian coordinates) and that the terms in the BST are not the momentum flux density and mean excess Eulerian stress but are simply contributions to the variation in the wave oscillation period resulting from changes in path length and true wave velocity, respectively, from virtual variations in the strain. It is shown that the radiation stress in Eulerian coordinates is the mean Cauchy stress (not the momentum flux density, as commonly assumed) and that Langevin's second relation does not yield an assessment of the mean Eulerian pressure, since the enthalpy used in the traditional derivations is a function of the thermodynamic tensions - not the Eulerian pressure. It is shown that the transformation between Lagrangian and Eulerian quantities cannot be obtained from the commonly-used expansion of one of the quantities in terms of the particle displacement, since the expansion provides only the difference between the value of the quantity at two different points in Cartesian space separated by the displacement. The proper transformation is obtained only by employing the transformation coefficients of finite deformation theory, which are defined in terms of the displacement gradients. Finite deformation theory leads to the result that for laterally unconfined, plane waves the Lagrangian and Eulerian radiation pressures are equal with the value (1/4)(2K) along the direction of wave propagation, where (K) is the mean kinetic energy density, and zero in directions normal to the propagation direction. This is contrary to the Langevin result that the Lagrangian radiation pressure in the propagation direction is equal to (2K) and the BST result that the Eulerian radiation pressure in that direction

  2. Blood Pressure Test

    Science.gov (United States)

    ... pressure monitors may have some limitations. Tracking your blood pressure readings It can be helpful in diagnosing or ... more Stage 2 high blood pressure (hypertension) Elevated blood pressure and stages 1 and 2 high blood pressure ( ...

  3. HETEROGENEOUS SHALLOW-SHELF CARBONATE BUILDUPS IN THE PARADOX BASIN, UTAH AND COLORADO: TARGETS FOR INCREASED OIL PRODUCTION AND RESERVES USING HORIZONTAL DRILLING TECHNIQUES. Semi-Annual Technical Progress Report April 6, 2000 - October 5, 2002

    International Nuclear Information System (INIS)

    Chidsey, Thomas C. Jr.

    2002-01-01

    The Paradox Basin of Utah, Colorado, Arizona, and New Mexico contains nearly 100 small oil fields producing from carbonate buildups within the Pennsylvanian (Desmoinesian) Paradox Formation. These fields typically have one to 10 wells with primary production ranging from 700,000 to 2,000,000 barrels (111,300-318,000 m 3 ) of oil per field and a 15 to 20 percent recovery rate. At least 200 million barrels (31.8 million m 3 ) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for horizontal drilling and enhanced oil recovery from existing, vertical, field wells based upon geological characterization and reservoir modeling case studies. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This report covers research activities for the first half of the third project year (April 6 through October 5, 2002). This work included capillary pressure/mercury injection analysis, scanning electron microscopy, and pore casting on selected samples from Cherokee and Bug fields, Utah. The diagenetic fabrics and porosity types found at these fields are indicators of reservoir flow capacity, storage capacity, and potential for enhanced oil recovery via horizontal drilling. The reservoir quality of Cherokee and Bug fields has been affected by multiple generations of dissolution, anhydrite plugging

  4. The Liquid Sustainer Build-up Time Impact on the Emptying Spacecraft Fuel Tank in Free Orbiting Conditions

    Directory of Open Access Journals (Sweden)

    V. B. Sapozhnikov

    2015-01-01

    Full Text Available Trouble-free operation of liquid rocket engines (LRE depends, among other factors, on the nonstop supply of liquid rocket fuel components in the fuel tank feed line with continuous flow.This condition becomes especially relevant for the aerial vehicles (AV in orbital (suborbital environment. With a little filled fuel tanks discontinuity of flow may occur because of pressurizing gas blow-by in the feed line as a result of the funnel generation (with or without vortex formation and so-called phenomenon of dynamic failure of the interface "liquid-gas”.The paper presents a mathematical model of the process of emptying tank initially a little filled and having a reduced level of the gravity acceleration. Using the developed mathematical model a parametric study has been conducted to find how stabilization rate of liquid flow effects on the volume of drained liquid. The computational experiment defines gas blow-by points in the feed line and propellant residuals, depending on the flow rate, physical properties of the fuel components, residual value of the acceleration, and diameter of the feed line.As a result, an effect is discovered that previously has been never mentioned in publications on research of the emptying processes of the aircraft fuel tanks, namely: with abrupt bootstrap of the flow rate a blow-by of gas occurs at the initial stage of emptying tank. In this case, to ensure LRE trouble-free operation there is a need in a special inner-tank device to prevent premature blow-by of pressurizing gas in the tank feed line.

  5. AAA and PBC calculation accuracy in the surface build-up region in tangential beam treatments. Phantom and breast case study with the Monte Carlo code PENELOPE

    International Nuclear Information System (INIS)

    Panettieri, Vanessa; Barsoum, Pierre; Westermark, Mathias; Brualla, Lorenzo; Lax, Ingmar

    2009-01-01

    Background and purpose: In tangential beam treatments accurate dose calculation of the absorbed dose in the build-up region is of major importance, in particular when the target has superficial extension close to the skin. In most analytical treatment planning systems (TPSs) calculations depend on the experimental measurements introduced by the user in which accuracy might be limited by the type of detector employed to perform them. To quantify the discrepancy between analytically calculated and delivered dose in the build-up region, near the skin of a patient, independent Monte Carlo (MC) simulations using the PENELOPE code were performed. Dose distributions obtained with MC simulations were compared with those given by the Pencil Beam Convolution (PBC) algorithm and the Analytical Anisotropic Algorithm (AAA) implemented in the commercial TPS Eclipse. Material and methods: A cylindrical phantom was used to approximate the breast contour of a patient for MC simulations and the TPS. Calculations of the absorbed doses were performed for 6 and 18 MV beams for four different angles of incidence: 15 deg., 30 deg., 45 deg. and 75 deg. and different field sizes: 3 x 3 cm 2 , 10 x 10 cm 2 and 40 x 40 cm 2 . Absorbed doses along the phantom central axis were obtained with both the PBC algorithm and the AAA and compared to those estimated by the MC simulations. Additionally, a breast patient case was calculated with two opposed 6 MV photon beams using all the aforementioned analytical and stochastic algorithms. Results: For the 6 MV photon beam in the phantom case, both the PBC algorithm and the AAA tend to underestimate the absorbed dose in the build-up region in comparison to MC results. These differences are clinically irrelevant and are included in a 1 mm range. This tendency is also confirmed in the breast patient case. For the 18 MV beam the PBC algorithm underestimates the absorbed dose with respect to the AAA. In comparison to MC simulations the PBC algorithm tends

  6. Time-resolved Shielded-Pickup Measurements and Modeling of Beam Conditioning Effects on Electron Cloud Buildup at CesrTA

    CERN Document Server

    Crittenden, J A; Liu, X; Palmer, M A; Santos, S; Sikora, J P; Kato, S; Calatroni, S; Rumolo, G

    2012-01-01

    The Cornell Electron Storage Ring Test Accelerator program includes investigations into electron cloud buildup in vacuum chambers with various coatings. Two 1.1-mlong sections located symmetrically in the east and west arc regions are equipped with BPM-like pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of 0.76 mm-diameter holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. We present new measurements of the effect of beam conditioning on a newly-installed amorphous carbon coated chamber, as well as on an extensively conditioned chamber with a diamond-like carbon coating. The ECLOUD modeling code is used to quantify the sensitivity of these measurements to model parameters, differentiating between photoelectron and secondary-electron production processes.

  7. GRAB - WRS system module number 60221 for calculating gamma-ray penetration in slab shields by the method of kernel integration with build-up factors

    International Nuclear Information System (INIS)

    Grimstone, M.J.

    1978-06-01

    The WRS Modular Programming System has been developed as a means by which programmes may be more efficiently constructed, maintained and modified. In this system a module is a self-contained unit typically composed of one or more Fortran routines, and a programme is constructed from a number of such modules. This report describes one WRS module, the function of which is to calculate the gamma-ray flux, dose, or heating rate in a slab shield using the build-up factor method. The information given in this manual is of use both to the programmer wishing to incorporate the module in a programme, and to the user of such a programme. (author)

  8. Study of the effect of external heating and internal temperature build-up during polymerization on the morphology of porous polymethacrylate adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Chan Yi, E-mail: vicchanyiwei@hotmail.com; Ongkudon, Clarence M., E-mail: clarence@ums.edu.my; Kansil, Tamar, E-mail: tamarkansil87@gmail.com [Biotechnology Research Institute, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah (Malaysia)

    2015-07-22

    Modern day synthesis protocols of methacrylate monolithic polymer adsorbent are based on existing polymerization blueprint without a thorough understanding of the dynamics of pore structure and formation. This has resulted in unproductiveness of polymer adsorbent consequently affecting purity and recovery of final product, productivity, retention time and cost effectiveness of the whole process. The problems magnified in monolith scaling-up where internal heat buildup resulting from external heating and high exothermic polymerization reaction was reflected in cracking of the adsorbent. We believe that through careful and precise control of the polymerization kinetics and parameters, it is possible to prepare macroporous methacrylate monolithic adsorbents with controlled pore structures despite being carried out in an unstirred mould. This research involved the study of the effect of scaling-up on pore morphology of monolith, in other words, porous polymethacrylate adsorbents that were prepared via bulk free radical polymerization process by imaging the porous morphology of polymethacrylate with scanning electron microscope.

  9. Together, slowly but surely: the role of social interaction and feedback in the build-up of benefit in collective decision-making

    DEFF Research Database (Denmark)

    Bahrami, Bahador; Olsen, Karsten; Bang, Dan

    2011-01-01

    That objective reference is necessary for formation of reliable beliefs about the external world is almost axiomatic. However, Condorcet (1785) suggested that purely subjective information-if shared and combined via social interaction-is enough for accurate understanding of the external world. We...... asked if social interaction and objective reference contribute differently to the formation and build-up of collective perceptual beliefs. In three experiments, dyads made individual and collective perceptual decisions in a two-interval, forced-choice, visual search task. In Experiment 1, participants...... negotiated their collective decisions with each other verbally and received feedback about accuracy at the end of each trial. In Experiment 2, feedback was not given. In Experiment 3, communication was not allowed but feedback was provided. Social interaction (Experiments 1 and 2 vs. 3) resulted...

  10. A-centres build-up kinetics in the conductive matrix of pulled n-type silicon with calculation of their recharges at defect clusters

    International Nuclear Information System (INIS)

    Dolgolenko, A.P.; Fishchuk, I.I.

    1981-01-01

    Pulled n-Si samples with rho approximately 40 Ωcm are investigated after irradiation with different doses of fast-pile neutrons. It is known that the simple defects are created not only in the conductive matrix but also in the region of the space charge of defect clusters. Then the charge state, for example, of A-centres in the region of the space charge is defined by both, the temperature and the value of the electrostatical potential. If this circumstance is not taken into account the calculation of the conductive volume is not precise enough. In the present paper the temperature dependence of the volume fraction is calculated, in which the space charge of defect clusters occurs, taking into account the recharges of A-centres in the region of the space charge. Using the expression obtained the A-centres build-up kinetics in the conductive matrix of pulled n-type silicon is calculated. (author)

  11. Comprehensive study on estimation of gamma-ray exposure buildup factors for smart polymers as a potent application in nuclear industries

    Science.gov (United States)

    Sayyed, M. I.; AlZaatreh, M. Y.; Matori, K. A.; Sidek, H. A. A.; Zaid, M. H. M.

    2018-06-01

    In the present study, the exposure buildup factors (EBF) have been investigated using geometric progression (G-P) fitting method for different types of smart polymers (DMSO, PDMS, PES, PMA, PVDC, and PVDF) in the energy range of 0.015-15 MeV. From the calculations, the values of the EBF were depended on the incident photon energy, penetration depth as well as chemical composition of the polymers. In the intermediate energy region, the EBF values were reached at maximum point while in low and high energy regions, the EBF values were decreased at minimum point. The obtained results of the selected polymers have been compared in terms of EBF with Al2O3 and other common polymers such as PAN, Teflon and SR. The shielding effectiveness of the selected polymers is found to be comparable to the common polymers. The results of this work should be useful in radiation shielding applications such as in industry, medical and nuclear engineering.

  12. Variation of energy absorption and exposure buildup factors with incident photon energy and penetration depth for boro-tellurite (B2O3-TeO2) glasses

    Science.gov (United States)

    Sayyed, M. I.; Elhouichet, H.

    2017-01-01

    The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) of (100-x)TeO2-xB2O3 glass systems (where x=5, 10, 15, 20, 22.5 and 25 mol%) have been calculated in the energy region 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path). The five parameters (G-P) fitting method has been used to estimate both EABF and EBF values. Variations of EABF and EBF with incident photon energy and penetration depth have been studied. It was found that EABF and EBF values were higher in the intermediate energy region, for all the glass systems. Furthermore, boro-tellurite glass with 5 mol% B2O3, was found to present the lowest EABF and EBF values, hence it is superior gamma-ray shielding material. The results indicate that the boro-tellurite glasses can be used as radiation shielding materials.

  13. Regional cerebral perfusion measurements: a comparative study of xenon-enhanced CT and C15O2 build-up using dynamic PET

    International Nuclear Information System (INIS)

    St Lawrence, K.S.; Bews, J.; Dunscombe, P.B.

    1992-01-01

    Regional cerebral perfusion can be determined by monitoring the uptake of a diffusable tracer concurrently in cerebral tissue and arterial blood. Two techniques based on this methodology are xenon-enhanced computed tomography (Xe CT) and C 15 O 2 build-up using dynamic positron emission tomography (C 15 O 2 PET). Serial images are used by both Xe CT and C 15 O 2 PET to characterize the uptake of the tracer in cerebral tissue. The noise present in these images will reduce the precision of the perfusion measurements obtained by either technique. Using Monte Carlo type computer simulations, the precision of the two techniques as a function of image noise has been examined. On the basis of their results, they conclude that the precision of the Xe CT technique is comparable to the precision of C 15 O 2 PET when realistic clinical protocols are employed for both. (author)

  14. SU-E-J-239: Influence of RF Coil Materials On Surface and Buildup Dose From a 6MV Photon Beam

    Energy Technology Data Exchange (ETDEWEB)

    Ghila, A; Fallone, B; Rathee, S [Cross Cancer Institute, Edmonton, AB (United Kingdom)

    2015-06-15

    Purpose: In order to perform real time tumour tracking using an integrated Linac-MR, images have to be acquired during irradiation. MRI uses RF coils in close proximity to the imaged volume. Given current RF coil designs this means that the high energy photons will be passing through the coil before reaching the patient. This study experimentally investigates the dose modifications that occur due to the presence of various RF coil materials in the treatment beam. Methods: Polycarbonate, copper or aluminum tape, and Teflon were used to emulate the base, conductor and cover respectively of a surface RF coil. These materials were placed at various distances from the surface of polystyrene or solid water phantoms which were irradiated in the presence of no magnetic field, a transverse 0.2T magnetic field, and a parallel 0.2T magnetic field. Percent depth doses were measured using ion chambers. Results: A significant increase in surface and buildup dose is observed. The surface dose is seen to decrease with an increasing separation between the emulated coil and the phantom surface, when no magnetic field is present. When a transverse magnetic field is applied the surface dose decreases faster with increasing separation, as some of the electrons created in the coil are curved away from the phantom’s surface. When a parallel field is present the surface dose stays approximately constant for small separations, only slightly decreasing for separations greater than 5cm, since the magnetic field focuses the electrons produced in the coil materials not allowing them to scatter. Conclusion: Irradiating a patient through an RF coil leads to an increase in the surface and buildup doses. Mitigating this increase is important for the successful clinical use of either a transverse or a parallel configuration Linac-MR unit. This project is partially supported by an operating grant from the Canadian Institute of Health Research (CIHR MOP 93752)

  15. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    International Nuclear Information System (INIS)

    Maekelae, K.; Laitinen, T.; Bojinov, M.

    1999-03-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for 60 Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.)

  16. The Influence Of Modified Water Chemistries On Metal Oxide Films, Activity Build-Up And Stress Corrosion Cracking Of Structural Materials In Nuclear Power Plants

    International Nuclear Information System (INIS)

    Maekelae, K.; Laitinen, T.; Bojinov, M.

    1998-07-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of activated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for 60 Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (author)

  17. The influence of modified water chemistries on metal oxide films, activity build-up and stress corrosion cracking of structural materials in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Maekelae, K.; Laitinen, T.; Bojinov, M. [VTT Manufacturing Technology, Espoo (Finland)

    1999-03-01

    The primary coolant oxidises the surfaces of construction materials in nuclear power plants. The properties of the oxide films influence significantly the extent of incorporation of actuated corrosion products into the primary circuit surfaces, which may cause additional occupational doses for the maintenance personnel. The physical and chemical properties of the oxide films play also an important role in different forms of corrosion observed in power plants. This report gives a short overview of the factors influencing activity build-up and corrosion phenomena in nuclear power plants. Furthermore, the most recent modifications in the water chemistry to decrease these risks are discussed. A special focus is put on zinc water chemistry, and a preliminary discussion on the mechanism via which zinc influences activity build-up is presented. Even though the exact mechanisms by which zinc acts are not yet known, it is assumed that Zn may block the diffusion paths within the oxide film. This reduces ion transport through the oxide films leading to a reduced rate of oxide growth. Simultaneously the number of available adsorption sites for {sup 60}Co is also reduced. The current models for stress corrosion cracking assume that the anodic and the respective cathodic reactions contributing to crack growth occur partly on or in the oxide films. The rates of these reactions may control the crack propagation rate and therefore, the properties of the oxide films play a crucial role in determining the susceptibility of the material to stress corrosion cracking. Finally, attention is paid also on the novel techniques which can be used to mitigate the susceptibility of construction materials to stress corrosion cracking. (orig.) 127 refs.

  18. Study of Diagenetic Features in Rudist Buildups of Cretaceous Edwards Formation Using Ground Based Hyperspectral Scanning and Terrestrial LiDAR

    Science.gov (United States)

    Krupnik, D.; Khan, S.; Okyay, U.; Hartzell, P. J.; Biber, K.

    2015-12-01

    Ground based remote sensing is a novel technique for development of digital outcrop models which can be instrumental in performing detailed qualitative and quantitative sedimentological analysis for the study of depositional environment, diagenetic processes, and hydrocarbon reservoir characterization. For this investigation, ground-based hyperspectral data collection is combined with terrestrial LiDAR to study outcrops of Late Albian rudist buildups of the Edwards formation in the Lake Georgetown Spillway in Williamson County, Texas. The Edwards formation consists of shallow water deposits of reef and associated inter-reef facies, including rudist bioherms and biostromes. It is a significant aquifer and was investigated as a hydrocarbon play in south central Texas. Hyperspectral data were used to map compositional variation in the outcrop by distinguishing spectral properties unique to each material. Lithological variation was mapped in detail to investigate the structure and composition of rudist buildups. Hyperspectral imagery was registered to a 3D model produced from the LiDAR point cloud with an accuracy of up to one pixel. Flat-topped toucasid-rich bioherm facies were distinguished from overlying toucasid-rich biostrome facies containing chert nodules, overlying sucrosic dolostones, and uppermost peloid wackestones and packstones of back-reef facies. Ground truth was established by petrographic study of samples from this area and has validated classification products of remote sensing data. Several types of porosity were observed and have been associated with increased dolomitization. This ongoing research involves integration of remotely sensed datasets to analyze geometrical and compositional properties of this carbonate formation at a finer scale than traditional methods have achieved and seeks to develop a workflow for quick and efficient ground based remote sensing-assisted outcrop studies.

  19. Analysis of the summertime buildup of tropospheric ozone abundances over the Middle East and North Africa as observed by the Tropospheric Emission Spectrometer instrument

    Science.gov (United States)

    Liu, Jane J.; Jones, Dylan B. A.; Worden, John R.; Noone, David; Parrington, Mark; Kar, Jay

    2009-03-01

    We use the GEOS-Chem chemical transport model to interpret observations of tropospheric ozone from the Tropospheric Emission Spectrometer (TES) satellite instrument in summer 2005. Observations from TES reveal elevated ozone in the middle troposphere (500-400 hPa) across North Africa and the Middle East. Observed ozone abundances in the middle troposphere are at a maximum in summer and a minimum in winter, consistent with the previously predicted summertime "Middle East ozone maximum." This summertime enhancement in ozone is associated with the Arabian and Sahara anticyclones, centered over the Zagros and Atlas Mountains, respectively. These anticyclones isolate the middle troposphere over northeast Africa and the Middle East, with westerlies to the north and easterlies to the south, facilitating the buildup of ozone. Over the Middle East, we find that in situ production and transport from Asia provides comparable contributions of 30-35% to the ozone buildup. Over North Africa, in situ production is dominant (at about 20%), with transport from Asia, North America, and equatorial Africa each contributing about 10-15% to the total ozone. We find that although the eastern Mediterranean is characterized by strong descent in the middle and upper troposphere in summer, transport from the boundary layer accounts for about 25% of the local Middle Eastern contribution to the ozone enhancement in the middle troposphere. This upward transport of boundary layer air is associated with orographic lifting along the Zagros Mountains in Iran and the Asir and Hijaz Mountain ranges in Saudi Arabia, and is consistent with TES observations of deuterated water.

  20. Periodic table of elements

    International Nuclear Information System (INIS)

    Fluck, E.; Heumann, K.G.

    1985-01-01

    Following a recommendation by the International Union for Pure and Applied Chemistry (IUPAC), the groups of the periodic table shall be numbered from 1 to 18, instead of I to VIII as before. The recommendations has been approved of by the Committee on Nomenclature of the American Chemical Society. The new system abandons the distinction between main groups (a) and auxiliary groups (b), which in the past frequently has been the reason for misunderstandings between European and American chemists, due to different handling. The publishing house VCH Verlagsgesellschaft recently produced a new periodic table that shows the old and the new numbering system together at a glance, so that chemists will have time to get familiar with the new system. In addition the new periodic table represents an extensive data compilation arranged by elements. The front page lists the chemical properties of elements, the back page their physical properties. (orig./EF) [de

  1. Thyrotoxic periodic paralysis

    Directory of Open Access Journals (Sweden)

    Rojith Karandode Balakrishnan

    2011-01-01

    Full Text Available This article aims at highlighting the importance of suspecting thyrotoxicosis in cases of recurrent periodic flaccid paralysis; especially in Asian men to facilitate early diagnosis of the former condition. A case report of a 28 year old male patient with recurrent periodic flaccid paralysis has been presented. Hypokalemia secondary to thyrotoxicosis was diagnosed as the cause of the paralysis. The patient was given oral potassium intervention over 24 hours. The patient showed complete recovery after the medical intervention and was discharged after 24 hours with no residual paralysis. Thyrotoxic periodic paralysis (TPP is a complication of thyrotoxicosis, more common amongst males in Asia. It presents as acute flaccid paralysis in a case of hyperthyroidism with associated hypokalemia. The features of thyrotoxicosis may be subtle or absent. Thus, in cases of recurrent or acute flaccid muscle paralysis, it is important to consider thyrotoxicosis as one of the possible causes, and take measures accordingly.

  2. Layer-by-layer buildup of polysaccharide-containing films: Physico-chemical properties and mesenchymal stem cells adhesion.

    Science.gov (United States)

    Kulikouskaya, Viktoryia I; Pinchuk, Sergei V; Hileuskaya, Kseniya S; Kraskouski, Aliaksandr N; Vasilevich, Irina B; Matievski, Kirill A; Agabekov, Vladimir E; Volotovski, Igor D

    2018-03-22

    Layer-by-Layer assembled polyelectrolyte films offer the opportunity to control cell attachment and behavior on solid surfaces. In the present study, multilayer films based on negatively charged biopolymers (pectin, dextran sulfate, carboxymethylcellulose) and positively charged polysaccharide chitosan or synthetic polyelectrolyte polyethyleneimine has been prepared and evaluated. Physico-chemical properties of the formed multilayer films, including their growth, morphology, wettability, stability, and mechanical properties, have been studied. We demonstrated that chitosan-containing films are characterized by the linear growth, the defect-free surface, and predominantly viscoelastic properties. When chitosan is substituted for the polyethyleneimine in the multilayer system, the properties of the formed films are significantly altered: the rigidity and surface roughness increases, the film growth acquires the exponential character. The multilayer films were subsequently used for culturing mesenchymal stem cells. It has been determined that stem cells effectively adhered to chitosan-containing films and formed on them the monolayer culture of fibroblast-like cells with high viability. Our results show that cell attachment is a complex process which is not only governed by the surface functionality because one of the key parameter effects on cell adhesion is the stiffness of polyelectrolyte multilayer films. We therefore propose our Layer-by-Layer films for applications in tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018. © 2018 Wiley Periodicals, Inc.

  3. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  4. Hereditary periodic fever syndromes

    NARCIS (Netherlands)

    McDermott, MF; Frenkel, J

    Hereditary periodic fever syndromes are defined by recurrent attacks of generalised inflammation for which no infectious or auto-immune cause can be identified. For most of these disorders, the molecular basis has recently been elucidated. This has opened the prospect of novel therapeutic

  5. Almost periodic Schroedinger operators

    International Nuclear Information System (INIS)

    Bellissard, J.; Lima, R.

    1984-01-01

    These lectures are devoted to recent developments in the theory of almost-periodic Schroedinger Operators. We specially describe the algebraic point of view, with applications to gap-labelling theorems. Particular models are also presented which exhibit various spectral properties. (orig.)

  6. Astrophysical implications of periodicity

    International Nuclear Information System (INIS)

    Muller, R.A.

    1988-01-01

    Two remarkable discoveries of the last decade have profound implications for astrophysics and for geophysics. These are the discovery by Alvarez et al., that certain mass extinctions are caused by the impact on the earth of a large asteroid or comet, and the discovery by Raup and Sepkoski that such extinctions are periodic, with a cycle time of 26 to 30 million years. The validity of both of these discoveries is assumed and the implications are examined. Most of the phenomena described depend not on periodicity, but just on the weaker assumption that the impacts on the earth take place primarily in showers. Proposed explanations for the periodicity include galactic oscillations, the Planet X model, and the possibility of Nemesis, a solar companion star. These hypotheses are critically examined. Results of the search for the solar companion are reported. The Deccan flood basalts of India have been proposed as the impact site for the Cretaceous impact, but this hypotheisis is in contradiction with the conclusion of Courtillot et al., that the magma flow began during a period of normal magnetic field. A possible resolution of this contradiction is proposed

  7. Periodic Table of Students.

    Science.gov (United States)

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  8. A Modern Periodic Table.

    Science.gov (United States)

    Herrenden-Harker, B. D.

    1997-01-01

    Presents a modern Periodic Table based on the electron distribution in the outermost shell and the order of filling of the sublevels within the shells. Enables a student to read off directly the electronic configuration of the element and the order in which filling occurs. (JRH)

  9. Thermo-mechanical analysis of the pressure plate of clutch

    Directory of Open Access Journals (Sweden)

    P.V.N. Venkata Mallikarjuna

    2017-09-01

    Full Text Available High Temperature appears in the contact surfaces of a clutch system (friction surface and pressure plate due to the relative motion between these parts during the sliding period. These high temperatures are responsible for several failures such as pressure plate crack, pressure plate warpage etc. With the help of Finite element analysis, the sliding friction process of the pressure plate and friction during clutch engagement is simulated to get temperature field characteristics and contact pressure of pressure plate.

  10. Periodic inspection of CANDU nuclear power plant containment components

    International Nuclear Information System (INIS)

    1989-09-01

    This Standard is one in a series intended to provide uniform requirements for CANDU nuclear power plants. It provides requirements for the periodic inspection of containment components including the containment pressure suppression systems

  11. Thyrotoxic periodic paralysis

    International Nuclear Information System (INIS)

    Ferreiro, J.E.; Arguelles, D.J.; Rams, H. Jr.

    1986-01-01

    A case of thyrotoxic periodic paralysis is reported in a Hispanic man with an unusual recurrence six weeks after radioactive iodine treatment. Thyrotoxic periodic paralysis has now been well characterized in the literature: it occurs primarily in Orientals with an overwhelming male preponderance and a higher association of specific HLA antigens. Clinical manifestations include onset after high carbohydrate ingestion or heavy exertion, with progressive symmetric weakness leading to flaccid paralysis of the extremities and other muscle groups, lasting several hours. If hypokalemia is present, potassium administration may help abort the attack. Although propranolol can be efficacious in preventing further episodes, the only definitive treatment is establishing a euthyroid state. The pathophysiology is still controversial, but reflects altered potassium and calcium dynamics as well as certain morphologic characteristics within the muscle unit itself

  12. Evaluation of build-up dose from 6 MV X-rays under pelvic and abdominal patient immobilisation devices

    Energy Technology Data Exchange (ETDEWEB)

    Cheung Tsang; Butson, M.J.Martin J. E-mail: mbutson@usa.netmbutson@guessmail.com; Yu, P.K.N

    2002-06-01

    The use of pelvic and abdominal immobilisation devices in radiotherapy is required for accurate positioning and repositioning of patients during their fractionated treatment delivered normally over a period of 5-6 weeks. 6 MV X-rays produced by a medical linear accelerator have a skin sparing effect whereby the skin dose delivered is considerably less than that received by the tumour. The treatment through a vacuum compressed immobilisation device (Vacbag) however increases the dose delivered to the skin by interactions of the X-rays within the Vacbag material. For example, the basal layer doses increased from 16% for an open field to 52% of maximum with a bag thickness of 2.5 cm for a 10 cmx10 cm field at 6 MV X-ray energy. At the same field size the dermal skin layer (1 mm depth) doses increased from 44% (no bag) to 60% for a bag thickness of 2.5 cm at 6 MV X-rays. The Vacbag should be placed outside the treatment field whenever possible to keep skin dose to a minimum level.

  13. Evaluation of build-up dose from 6 MV X-rays under pelvic and abdominal patient immobilisation devices

    International Nuclear Information System (INIS)

    Cheung Tsang; Butson, M.J.Martin J.; Yu, P.K.N.

    2002-01-01

    The use of pelvic and abdominal immobilisation devices in radiotherapy is required for accurate positioning and repositioning of patients during their fractionated treatment delivered normally over a period of 5-6 weeks. 6 MV X-rays produced by a medical linear accelerator have a skin sparing effect whereby the skin dose delivered is considerably less than that received by the tumour. The treatment through a vacuum compressed immobilisation device (Vacbag) however increases the dose delivered to the skin by interactions of the X-rays within the Vacbag material. For example, the basal layer doses increased from 16% for an open field to 52% of maximum with a bag thickness of 2.5 cm for a 10 cmx10 cm field at 6 MV X-ray energy. At the same field size the dermal skin layer (1 mm depth) doses increased from 44% (no bag) to 60% for a bag thickness of 2.5 cm at 6 MV X-rays. The Vacbag should be placed outside the treatment field whenever possible to keep skin dose to a minimum level

  14. Low Blood Pressure

    Science.gov (United States)

    ... a problem. Sometimes blood pressure that is too low can also cause problems. Blood pressure is the ... reading is 90/60 or lower, you have low blood pressure. Some people have low blood pressure ...

  15. Low Blood Pressure (Hypotension)

    Science.gov (United States)

    ... lowest at night and rises sharply on waking. Blood pressure: How low can you go? What's considered low ... low blood pressure. Medications that can cause low blood pressure Some medications can cause low blood pressure, including: ...

  16. Normal Pressure Hydrocephalus (NPH)

    Science.gov (United States)

    ... local chapter Join our online community Normal Pressure Hydrocephalus (NPH) Normal pressure hydrocephalus is a brain disorder ... Symptoms Diagnosis Causes & risks Treatments About Normal Pressure Hydrocephalus Normal pressure hydrocephalus occurs when excess cerebrospinal fluid ...

  17. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... of a pressure sore required? play_arrow How long is the typical healing time for a pressure ... arrow Why do some pressure sores take so long to heal? play_arrow Can a pressure sore ...

  18. Optical fiber powered pressure sensor

    International Nuclear Information System (INIS)

    Schweizer, P.; Neveux, L.; Ostrowsky, D.B.

    1987-01-01

    In the system described, a pressure sensor and its associated electronics are optically powered by a 20 mw laser and a photovoltaic cell via an optical fiber. The sensor is periodically interrogated and sends the measures obtained back to the central unit using an LED and a second fiber. The results obtained as well as the expected evolution will be described

  19. Temperature control for high pressure processes up to 1400 MPa

    International Nuclear Information System (INIS)

    Reineke, K; Mathys, A; Knorr, D; Heinz, V

    2008-01-01

    Pressure- assisted sterilisation is an emerging technology. Hydrostatic high pressure can reduce the thermal load of the product and this allows quality retention in food products. To guarantee the safety of the sterilisation process it is necessary to investigate inactivation kinetics especially of bacterial spores. A significant roll during the inactivation of microorganisms under high pressure has the thermodynamic effect of the adiabatic heating. To analyse the individual effect of pressure and temperature on microorganism inactivation an exact temperature control of the sample to reach ideal adiabatic conditions and isothermal dwell times is necessary. Hence a heating/cooling block for a high pressure unit (Stansted Mini-Food-lab; high pressure capillary with 300 μL sample volume) was constructed. Without temperature control the sample would be cooled down during pressure built up, because of the non-adiabatic heating of the steel made vessel. The heating/cooling block allows an ideal adiabatic heat up and cooling of the pressure vessel during compression and decompression. The high pressure unit has a pressure build-up rate up to 250 MPa s -1 and a maximum pressure of 1400 MPa. Sebacate acid was chosen as pressure transmitting medium because it had no phase shift over the investigate pressure and temperature range. To eliminate the temperature difference between sample and vessel during compression and decompression phase, the mathematical model of the adiabatic heating/cooling of water and sebacate acid was implemented into a computational routine, written in Test Point. The calculated temperature is the setpoint of the PID controller for the heating/cooling block. This software allows an online measurement of the pressure and temperature in the vessel and the temperature at the outer wall of the vessel. The accurate temperature control, including the model of the adiabatic heating opens up the possibility to realise an ideal adiabatic heating and cooling

  20. Spinal Cord Injury and Pressure Ulcer Prevention: Using Functional Activity in Pressure Relief

    OpenAIRE

    Stinson, May; Schofield, Rachel; Gillan, Cathy; Morton, Julie; Gardner, Evie; Sprigle, Stephen; Porter-Armstrong, Alison

    2013-01-01

    Background. People with spinal cord injury (SCI) are at increased risk of pressure ulcers due to prolonged periods of sitting. Concordance with pressure relieving movements is poor amongst this population, and one potential alternative to improve this would be to integrate pressure relieving movements into everyday functional activities. Objectives. To investigate both the current pressure relieving behaviours of SCI individuals during computer use and the application of an ergonomically adap...

  1. In-situ buildup of cosmogenic isotopes at the earth`s surface: measurement of erosion rates and exposure times

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, L K; Allan, G L; Stone, J O.H.; Evans, J M; Cresswell, R G; Ophel, T R [Australian National Univ., Canberra, ACT (Australia)

    1994-12-31

    Cosmic rays produce a number of nuclides in rocks that can be used to determine the geomorphic history of surfaces. The most useful are the radioactive isotopes {sup 10}Be (t{sub 1/2} = 1.5Ma), {sup 26}Al (0.7Ma) and {sup 36}Cl (0.3Ma). Within the top 2m of the surface, these are produced principally by fast neutrons. At greater depths, production is dominated by the capture of negative muons. Measurements of a single nuclide produced in situ can be used to determine total exposure times or erosion rates. The use of multiple nuclides with different half-lives makes it possible to determine more complex histories, such as exposures interrupted by periods of burial. At the ANU, all three of the isotopes above are being used to study a variety of problems in geomorphology and paleoclimatology, although to date, most of the work has concentrated on {sup 36}Cl. The accumulation of cosmogenic {sup 36}Cl in calcite (CaCO{sub 3}) provides a means of measuring erosion rates on limestone surfaces. Sensitivity is achieved over a wide range of erosion rates due to the high production rate of {sup 36}Cl in calcite (typically greater than 30 atoms/g/yr) and a detection limit of ca. 5000 atoms/g attainable with the ANU AMS system. The method is simplified by the predominance of Ca reactions (principally spallation) over other sources of {sup 36}Cl in calcite, and the ease of sample preparation. This presentation discuss the results of measurements of {sup 36}Cl in calcite from limestone samples from Australia and Papua New Guinea. Erosion rates derived from these measurements range from 3 microns per year (Australia) to over 200 microns per year in the New Guinea highlands. 3 refs.

  2. In-situ buildup of cosmogenic isotopes at the earth's surface: measurement of erosion rates and exposure times

    International Nuclear Information System (INIS)

    Fifield, L.K.; Allan, G.L.; Stone, J.O.H.; Evans, J.M.; Cresswell, R.G.; Ophel, T.R.

    1993-01-01

    Cosmic rays produce a number of nuclides in rocks that can be used to determine the geomorphic history of surfaces. The most useful are the radioactive isotopes 10 Be (t 1/2 = 1.5Ma), 26 Al (0.7Ma) and 36 Cl (0.3Ma). Within the top 2m of the surface, these are produced principally by fast neutrons. At greater depths, production is dominated by the capture of negative muons. Measurements of a single nuclide produced in situ can be used to determine total exposure times or erosion rates. The use of multiple nuclides with different half-lives makes it possible to determine more complex histories, such as exposures interrupted by periods of burial. At the ANU, all three of the isotopes above are being used to study a variety of problems in geomorphology and paleoclimatology, although to date, most of the work has concentrated on 36 Cl. The accumulation of cosmogenic 36 Cl in calcite (CaCO 3 ) provides a means of measuring erosion rates on limestone surfaces. Sensitivity is achieved over a wide range of erosion rates due to the high production rate of 36 Cl in calcite (typically greater than 30 atoms/g/yr) and a detection limit of ca. 5000 atoms/g attainable with the ANU AMS system. The method is simplified by the predominance of Ca reactions (principally spallation) over other sources of 36 Cl in calcite, and the ease of sample preparation. This presentation discuss the results of measurements of 36 Cl in calcite from limestone samples from Australia and Papua New Guinea. Erosion rates derived from these measurements range from 3 microns per year (Australia) to over 200 microns per year in the New Guinea highlands. 3 refs

  3. In-situ buildup of cosmogenic isotopes at the earth`s surface: measurement of erosion rates and exposure times

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, L.K.; Allan, G.L.; Stone, J.O.H.; Evans, J.M.; Cresswell, R.G.; Ophel, T.R. [Australian National Univ., Canberra, ACT (Australia)

    1993-12-31

    Cosmic rays produce a number of nuclides in rocks that can be used to determine the geomorphic history of surfaces. The most useful are the radioactive isotopes {sup 10}Be (t{sub 1/2} = 1.5Ma), {sup 26}Al (0.7Ma) and {sup 36}Cl (0.3Ma). Within the top 2m of the surface, these are produced principally by fast neutrons. At greater depths, production is dominated by the capture of negative muons. Measurements of a single nuclide produced in situ can be used to determine total exposure times or erosion rates. The use of multiple nuclides with different half-lives makes it possible to determine more complex histories, such as exposures interrupted by periods of burial. At the ANU, all three of the isotopes above are being used to study a variety of problems in geomorphology and paleoclimatology, although to date, most of the work has concentrated on {sup 36}Cl. The accumulation of cosmogenic {sup 36}Cl in calcite (CaCO{sub 3}) provides a means of measuring erosion rates on limestone surfaces. Sensitivity is achieved over a wide range of erosion rates due to the high production rate of {sup 36}Cl in calcite (typically greater than 30 atoms/g/yr) and a detection limit of ca. 5000 atoms/g attainable with the ANU AMS system. The method is simplified by the predominance of Ca reactions (principally spallation) over other sources of {sup 36}Cl in calcite, and the ease of sample preparation. This presentation discuss the results of measurements of {sup 36}Cl in calcite from limestone samples from Australia and Papua New Guinea. Erosion rates derived from these measurements range from 3 microns per year (Australia) to over 200 microns per year in the New Guinea highlands. 3 refs.

  4. Polysheroidal periodic functions

    International Nuclear Information System (INIS)

    Truskova, N.F.

    1985-01-01

    Separation of variables in the Helmholtz N-dimensional (N≥4) equation in polyspheroidal coordinate systems leads to the necessity of solving equations going over into equations for polyspheroidal periodic functions used for solving the two-centre problem in quantum mechanics, the three-body problem with Coulomb interaction, etc. For these functions the expansions are derived in terms of the Jacobi polynomials and Bessel functions. Their basic properties, asymptotics are considered. The algorithm of their computer calculations is developed. The results of numerical calculations are given

  5. Deciphering Periodic Methanol Masers

    Science.gov (United States)

    Stecklum, Bringfried; Caratti o Garatti, Alessio; Henning, Thomas; Hodapp, Klaus; Hopp, Ulrich; Kraus, Alex; Linz, Hendrik; Sanna, Alberto; Sobolev, Andrej; Wolf, Verena

    2018-05-01

    Impressive progress has been made in recent years on massive star formation, yet the involved high optical depths even at submm/mm wavelengths make it difficult to reveal its details. Recently, accretion bursts of massive YSOs have been identified to cause flares of Class II methanol masers (methanol masers for short) due to enhanced mid-IR pumping. This opens a new window to protostellar accretion variability, and implies that periodic methanol masers hint at cyclic accretion. Pinning down the cause of the periodicity requires joint IR and radio monitoring. We derived the first IR light curve of a periodic maser host from NEOWISE data. The source, G107.298+5.639, is an intermediate-mass YSO hosting methanol and water masers which flare every 34.5 days. Our recent joint K-band and radio observations yielded first but marginal evidence for a phase lag between the rise of IR and maser emission, respectively, and revealed that both NEOWISE and K-band light curves are strongly affected by the light echo from the ambient dust. Both the superior resolution of IRAC over NEOWISE and the longer wavelengths compared to our ground-based imaging are required to inhibit the distractive contamination by the light echo. Thus, we ask for IRAC monitoring of G107 to cover one flare cycle, in tandem with 100-m Effelsberg and 2-m Wendelstein radio and NIR observations to obtain the first high-quality synoptic measurements of this kind of sources. The IR-maser phase lag, the intrinsic shape of the IR light curves and their possible color variation during the cycle allow us to constrain models for the periodic maser excitation. Since methanol masers are signposts of intermediate-mass and massive YSOs, deciphering their variability offers a clue to the dynamics of the accretion-mediated growth of massive stars and their feedback onto the immediate natal environment. The Spitzer light curve of such a maser-hosting YSO would be a legacy science product of the mission.

  6. Optimization and Control of Pressure Swing Adsorption Processes Under Uncertainty

    KAUST Repository

    Khajuria, Harish; Pistikopoulos, Efstratios N.

    2012-01-01

    The real-time periodic performance of a pressure swing adsorption (PSA) system strongly depends on the choice of key decision variables and operational considerations such as processing steps and column pressure temporal profiles, making its design

  7. Plantar pressure during gait in pregnant women

    OpenAIRE

    Bertuit, Jeanne; Leyh, Clara; Rooze, Marcel; Feipel, Véronique

    2016-01-01

    Background: During pregnancy, physical and hormonal modifications occur. Morphologic alterations of the feet are found. These observations can induce alterations in plantar pressure. This study sought to investigate plantar pressures during gait in the last 4 months of pregnancy and in the postpartum period. A comparison with nulliparous women was conducted to investigate plantar pressure modifications during pregnancy. Methods: Fifty-eight women in the last 4 months of pregnancy, nine postpa...

  8. Periodically modulated dark states

    Science.gov (United States)

    Han, Yingying; Zhang, Jun; Zhang, Wenxian

    2018-04-01

    Phenomena of electromagnetically induced transparency (PEIT) may be interpreted by the Autler-Townes Splitting (ATS), where the coupled states are split by the coupling laser field, or by the quantum destructive interference (QDI), where the atomic phases caused by the coupling laser and the probe laser field cancel. We propose modulated experiments to explore the PEIT in an alternative way by periodically modulating the coupling and the probe fields in a Λ-type three-level system initially in a dark state. Our analytical and numerical results rule out the ATS interpretation and show that the QDI interpretation is more appropriate for the modulated experiments. Interestingly, dark state persists in the double-modulation situation where control and probe fields never occur simultaneously, which is significant difference from the traditional dark state condition. The proposed experiments are readily implemented in atomic gases, artificial atoms in superconducting quantum devices, or three-level meta-atoms in meta-materials.

  9. Ecloud Build-Up Simulations for the FNAL MI for a Mixed Fill Pattern: Dependence on Peak SEY and Pulse Intensity During the Ramp

    International Nuclear Information System (INIS)

    Furman, M.A.

    2010-01-01

    We present simulation results of the build-up of the electron-cloud density n e in three regions of the FNAL Main Injector (MI) for a beam fill pattern made up of 5 double booster batches followed by a 6th single batch. We vary the pulse intensity in the range N t = (2-5) x 10 13 , and the beam kinetic energy in the range E k = 8-120 GeV. We assume a secondary electron emission model qualitatively corresponding to TiN, except that we let the peak value of the secondary electron yield (SEY) (delta) max vary as a free parameter in a fairly broad range. Our main conclusions are: (1) At fixed N t there is a clear threshold behavior of n e as a function of (delta) max in the range ∼ 1.1-1.3. (2) At fixed (delta) max , there is a threshold behavior of n e as a function of N t provided (delta) max is sufficiently high; the threshold value of N t is a function of the characteristics of the region being simulated. (3) The dependence on E k is weak except possibly at transition energy. Most of these results were informally presented to the relevant MI personnel in April 2010.

  10. A THEORETICAL STUDY OF THE BUILD-UP OF THE SUN’S POLAR MAGNETIC FIELD BY USING A 3D KINEMATIC DYNAMO MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Hazra, Gopal; Choudhuri, Arnab Rai [Department of Physics, Indian Institute of Science, Bangalore, 560012 (India); Miesch, Mark S., E-mail: ghazra@physics.iisc.ernet.in, E-mail: arnab@physics.iisc.ernet.in, E-mail: miesch@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80301 (United States)

    2017-01-20

    We develop a three-dimensional kinematic self-sustaining model of the solar dynamo in which the poloidal field generation is from tilted bipolar sunspot pairs placed on the solar surface above regions of strong toroidal field by using the SpotMaker algorithm, and then the transport of this poloidal field to the tachocline is primarily caused by turbulent diffusion. We obtain a dipolar solution within a certain range of parameters. We use this model to study the build-up of the polar magnetic field and show that some insights obtained from surface flux transport models have to be revised. We present results obtained by putting a single bipolar sunspot pair in a hemisphere and two symmetrical sunspot pairs in two hemispheres. We find that the polar fields produced by them disappear due to the upward advection of poloidal flux at low latitudes, which emerges as oppositely signed radial flux and which is then advected poleward by the meridional flow. We also study the effect that a large sunspot pair, violating Hale’s polarity law, would have on the polar field. We find that there would be some effect—especially if the anti-Hale pair appears at high latitudes in the mid-phase of the cycle—though the effect is not very dramatic.

  11. Ecloud Build-Up Simulations for the FNAL MI for a Mixed Fill Pattern: Dependence on Peak SEY and Pulse Intensity During the Ramp

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M. A.

    2010-12-11

    We present simulation results of the build-up of the electron-cloud density n{sub e} in three regions of the FNAL Main Injector (MI) for a beam fill pattern made up of 5 double booster batches followed by a 6th single batch. We vary the pulse intensity in the range N{sub t} = (2-5) x 10{sup 13}, and the beam kinetic energy in the range E{sub k} = 8-120 GeV. We assume a secondary electron emission model qualitatively corresponding to TiN, except that we let the peak value of the secondary electron yield (SEY) {delta}{sub max} vary as a free parameter in a fairly broad range. Our main conclusions are: (1) At fixed N{sub t} there is a clear threshold behavior of n{sub e} as a function of {delta}{sub max} in the range {approx} 1.1-1.3. (2) At fixed {delta}{sub max}, there is a threshold behavior of n{sub e} as a function of N{sub t} provided {delta}{sub max} is sufficiently high; the threshold value of N{sub t} is a function of the characteristics of the region being simulated. (3) The dependence on E{sub k} is weak except possibly at transition energy. Most of these results were informally presented to the relevant MI personnel in April 2010.

  12. Electrophoretic build-up of alternately multilayered films and micropatterns based on graphene sheets and nanoparticles and their applications in flexible supercapacitors.

    Science.gov (United States)

    Niu, Zhiqiang; Du, Jianjun; Cao, Xuebo; Sun, Yinghui; Zhou, Weiya; Hng, Huey Hoon; Ma, Jan; Chen, Xiaodong; Xie, Sishen

    2012-10-22

    Graphene nanosheets and metal nanoparticles (NPs) have been used as nano-building-blocks for assembly into macroscale hybrid structures with promising performance in electrical devices. However, in most graphene and metal NP hybrid structures, the graphene sheets and metal NPs (e.g., AuNPs) do not enable control of the reaction process, orientation of building blocks, and organization at the nanoscale. Here, an electrophoretic layer-by-layer assembly for constructing multilayered reduced graphene oxide (RGO)/AuNP films and lateral micropatterns is presented. This assembly method allows easy control of the nano-architecture of building blocks along the normal direction of the film, including the number and thickness of RGO and AuNP layers, in addition to control of the lateral orientation of the resultant multilayered structures. Conductivity of multilayered RGO/AuNP hybrid nano-architecture shows great improvement caused by a bridging effect of the AuNPs along the out-of-plane direction between the upper and lower RGO layers. The results clearly show the potential of electrophoretic build-up in the fabrication of graphene-based alternately multilayered films and patterns. Finally, flexible supercapacitors based on multilayered RGO/AuNP hybrid films are fabricated, and excellent performance, such as high energy and power densities, are achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Periodic and in-service inspection programs

    International Nuclear Information System (INIS)

    Dinu, M.

    2000-01-01

    Periodic and in-service inspection programs for Cernavoda NPP consists of periodic inspections of CANDU NPP components CSAN N-285.4 and CSAN N-285.4, in-service inspections and repair and modifications general inspection. Periodic inspection program document (PIPD) determines the systems and components subject to inspection, the category of the inspection, techniques, areas and other details.The current status of the inspection programs is presented, including containment , erosion/corrosion, pressure vessel support and snubbers, main steam lines inspection programs. Qualification program in Cernavoda NPP involves equipment qualification in the on-site laboratory, yearly certification, special equipment qualification in the National Institute of Metrology. All procedures are approved by the ISCIR (regulatory body for pressure vessel and lifting equipment) and CNCAN (National Commission on Nuclear Activities Control). Qualification of the personnel is performed according to the ISCIR Technical prescription CR 11/82 for up to 3 year period. Final qualification and licensing is performed by CNCAN

  14. Line pressure effects on differential pressure measurements

    International Nuclear Information System (INIS)

    Neff, G.G.; Evans, R.P.

    1982-01-01

    The performance of differential pressure transducers in experimental pressurized water reactor (PWR) systems was evaluated. Transient differential pressure measurements made using a simple calibration proportionality relating differential pressure to output voltage could have large measurement uncertainties. A more sophisticated calibration equation was derived to incorporate the effects of zero shifts and sensitivity shifts as pressure in the pressure sensing line changes with time. A comparison made between the original calibration proportionality equation and the derived compensation equation indicates that potential measurement uncertainties can be reduced

  15. C-type period-doubling transition in nephron autoregulation

    DEFF Research Database (Denmark)

    Laugesen, Jakob Lund; Mosekilde, Erik; Holstein-Rathlou, Niels-Henrik

    2011-01-01

    The functional units of the kidney, called nephrons, utilize mechanisms that allow the individual nephron to regulate the incoming blood flow in response to fluctuations in the arterial pressure. This regulation tends to be unstable and to generate self-sustained oscillations, period-doubling bif......The functional units of the kidney, called nephrons, utilize mechanisms that allow the individual nephron to regulate the incoming blood flow in response to fluctuations in the arterial pressure. This regulation tends to be unstable and to generate self-sustained oscillations, period......-doubling bifurcations, mode-locking and other nonlinear dynamic phenomena in the tubular pressures and flows. Using a simplified nephron model, the paper examines how the regulatory mechanisms react to an external periodic variation in arterial pressure near a region of resonance with one of the internally generated...

  16. Magnetomechanically induced long period fiber gratings

    International Nuclear Information System (INIS)

    Causado-Buelvas, Jesus D.; Gomez-Cardona, Nelson D.; Torres, Pedro

    2008-01-01

    In this work, we report a simple, flexible method to create long period fiber gratings mechanically by controlling the repulsion/attraction force between two magnets that pressing a plate with a periodic array of small glass cylinders to a short length of optical fiber. Via the photoelastic effect, the pressure points induce the required periodic refractive index modulation to create the LPFG. We found that the induced device exhibits spectral characteristics similar to those of other types of LPFG. As the optical properties of LPFGs are directly related to the nature of the applied perturbations, we show, to our knowledge for the frrst time, how is the evolution of birefringence effects in mechanically induced LPFGs

  17. [Hypertension and pregnancy: Post-partum period].

    Science.gov (United States)

    Hugon-Rodin, Justine; Plu-Bureau, Geneviève

    2016-01-01

    Post-partum period is associated with specific characteristics in women with gestational disorders or preeclampsia. For breastfeeding women, the choice of antihypertensive treatment should take into account the impact on child health. The impact of breastfeeding on health mother must be also discussed. Moreover, for lactation inhibition, bromocriptine should not be used, especially in the context of gestational disorders. In post-partum period, the best contraceptive strategy is only-progestin contraception or non-hormonal contraceptives use. However, this choice will depend on the stabilization or normalization of blood pressure in early post-partum period. Finally, several consultations should be suggested: an information and announcement to explain the consequences of these gestational disorders and organize their multidisciplinary management and follow-up. A preconceptional consultation takes its place to anticipate potential recurrent preeclampsia or gestational hypertension and to schedule a future pregnancy in optimal conditions. Copyright © 2016. Published by Elsevier Masson SAS.

  18. [Childhood periodic syndromes].

    Science.gov (United States)

    Cuvellier, J-C; Lépine, A

    2010-01-01

    This review focuses on the so-called "periodic syndromes of childhood that are precursors to migraine", as included in the Second Edition of the International Classification of Headache Disorders. Three periodic syndromes of childhood are included in the Second Edition of the International Classification of Headache Disorders: abdominal migraine, cyclic vomiting syndrome and benign paroxysmal vertigo, and a fourth, benign paroxysmal torticollis is presented in the Appendix. The key clinical features of this group of disorders are the episodic pattern and intervals of complete health. Episodes of benign paroxysmal torticollis begin between 2 and 8 months of age. Attacks are characterized by an abnormal inclination and/or rotation of the head to one side, due to cervical dystonia. They usually resolve by 5 years. Benign paroxysmal vertigo presents as sudden attacks of vertigo, accompanied by inability to stand without support, and lasting seconds to minutes. Age at onset is between 2 and 4 years, and the symptoms disappear by the age of 5. Cyclic vomiting syndrome is characterized in young infants and children by repeated stereotyped episodes of pernicious vomiting, at times to the point of dehydration, and impacting quality of life. Mean age of onset is 5 years. Abdominal migraine remains a controversial issue and presents in childhood with repeated stereotyped episodes of unexplained abdominal pain, nausea and vomiting occurring in the absence of headache. Mean age of onset is 7 years. Both cyclic vomiting syndrome and abdominal migraine are noted for the absence of pathognomonic clinical features but also for the large number of other conditions to be considered in their differential diagnoses. Diagnostic criteria, such as those of the Second Edition of the International Classification of Headache Disorders and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition, have made diagnostic approach and management easier. Their diagnosis

  19. Nonparametric Inference for Periodic Sequences

    KAUST Repository

    Sun, Ying; Hart, Jeffrey D.; Genton, Marc G.

    2012-01-01

    the periodogram, a widely used tool for period estimation. The CV method is computationally simple and implicitly penalizes multiples of the smallest period, leading to a "virtually" consistent estimator of integer periods. This estimator is investigated both

  20. Positive pressure ventilation and cranial volume in newborn infants.

    OpenAIRE

    Milligan, D W

    1981-01-01

    The relationship between changes in airways pressure, pleural pressure, and cranial volume was studied in a group of sick newborn infants requiring ventilatory assistance. Cranial volume increased appreciably only when lung compliance was such that more than 20% of the applied airways pressure was transmitted to the pleural space, or if the absolute pleural pressure was greater than 4 cmH2O above atmospheric pressure. The findings stress the need for more-critical monitoring during periods of...

  1. Parent-Pressure

    DEFF Research Database (Denmark)

    Jensen, Helle Strandgaard

    2016-01-01

    of parents as co-consumers prevailed despite radical changes in views on children’s media consumption. In particular, I examine the shared inter-Scandinavian socio-cultural contexts that structured the changing professional and political groups’ pressure on parents to perform according to their norms......In this article, I examine change and continuity in conceptions of parental agency in public debates about children’s media consumption in Scandinavia, 1945-1975. During this period, public debates about the various kinds of media products children consumed were dominated by different groups....... However, a strong continuity in the debates was the negative influence parents were seen as having on children’s media consumption due to their lack of insight and interest in the topic. Drawing upon recent works on children’s media, consumption and enculturation, I analyse why the negative description...

  2. Critical pressure of non-equilibrium two-phase critical flow

    Energy Technology Data Exchange (ETDEWEB)

    Minzer, U [Israel Electric Corp. Ltd., Haifa (Israel)

    1996-12-01

    Critical pressure is defined as the pressure existing at the exit edge of the piping, when it remains constant despite a decrease in the back. According to this definition the critical pressure is larger than the back pressure and for two-phase conditions below saturation pressure. The two-phase critical pressure has a major influence on the two-phase critical flow characteristics. Therefore it is of High significance in calculations of critical mass flux and critical depressurization rate, which are important in the fields of Nuclear Reactor Safety and Industrial Safety. At the Nuclear Reactor Safety field is useful for estimations of the Reactor Cooling System depressurization, the core coolant level, and the pressure build-up in the containment. In the Industrial Safety field it is helpful for estimating the leakage rate of toxic gases Tom liquefied gas pressure vessels, depressurization of pressure vessels, and explosion conditions due to liquefied gas release. For physical description of non-equilibrium two-phase critical flow it would be convenient to divide the flow into two stages. The first stage is the flow of subcooled liquid at constant temperature and uniform pressure drop (i.e., the case of incompressible fluid and uniform piping cross section). The rapid flow of the liquid causes a delay in the boiling of the liquid, which begins to boil below saturation pressure, at thermal non-equilibrium. The boiling is the beginning of the second stage, characterized by a sharp increase of the pressure drop. The liquid temperature on the second stage is almost constant because most of the energy for vaporization is supplied from the large pressure drop The present work will focus on the two-phase critical pressure of water, since water serves as coolant in the vast majority of nuclear power reactors throughout the world. (author).

  3. Critical pressure of non-equilibrium two-phase critical flow

    International Nuclear Information System (INIS)

    Minzer, U.

    1996-01-01

    Critical pressure is defined as the pressure existing at the exit edge of the piping, when it remains constant despite a decrease in the back. According to this definition the critical pressure is larger than the back pressure and for two-phase conditions below saturation pressure. The two-phase critical pressure has a major influence on the two-phase critical flow characteristics. Therefore it is of High significance in calculations of critical mass flux and critical depressurization rate, which are important in the fields of Nuclear Reactor Safety and Industrial Safety. At the Nuclear Reactor Safety field is useful for estimations of the Reactor Cooling System depressurization, the core coolant level, and the pressure build-up in the containment. In the Industrial Safety field it is helpful for estimating the leakage rate of toxic gases Tom liquefied gas pressure vessels, depressurization of pressure vessels, and explosion conditions due to liquefied gas release. For physical description of non-equilibrium two-phase critical flow it would be convenient to divide the flow into two stages. The first stage is the flow of subcooled liquid at constant temperature and uniform pressure drop (i.e., the case of incompressible fluid and uniform piping cross section). The rapid flow of the liquid causes a delay in the boiling of the liquid, which begins to boil below saturation pressure, at thermal non-equilibrium. The boiling is the beginning of the second stage, characterized by a sharp increase of the pressure drop. The liquid temperature on the second stage is almost constant because most of the energy for vaporization is supplied from the large pressure drop The present work will focus on the two-phase critical pressure of water, since water serves as coolant in the vast majority of nuclear power reactors throughout the world. (author)

  4. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... play_arrow What is "sepsis," and why is it dangerous? play_arrow How common are pressure sores ... likely to develop pressure sores? play_arrow Is it true that a pressure sore can develop in ...

  5. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  6. High Blood Pressure Facts

    Science.gov (United States)

    ... Stroke Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir On ... Top of Page CDC Fact Sheets Related to High Blood Pressure High Blood Pressure Pulmonary Hypertension Heart Disease Signs ...

  7. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  8. Testing periodically integrated autoregressive models

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); M.J. McAleer (Michael)

    1997-01-01

    textabstractPeriodically integrated time series require a periodic differencing filter to remove the stochastic trend. A non-periodic integrated time series needs the first-difference filter for similar reasons. When the changing seasonal fluctuations for the non-periodic integrated series can be

  9. LPG based all plastic pressure sensor

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Lwin, R.; Leon-Saval, S.

    2015-01-01

    A prototype all-plastic pressure sensor is presented and characterized for potential use as an endoscope. The sensor is based on Long Period Gratings (LPG) inscribed with a CO2 laser in 6-ring microstructured PMMA fiber. Through a latex coated, plastic 3D-printed transducer pod, external pressure...... is converted to longitudinal elongation of the pod and therefore of the fiber containing the LPG. The sensor has been characterised for pressures of up to 160 mBar in an in-house built pressure chamber. Furthermore, the influence of the fiber prestrain, fiber thickness and the effect of different glues...

  10. Fall in blood pressure during radiation therapy

    International Nuclear Information System (INIS)

    Larsson, L.E.; Lindahl, J.; Unsgaard, B.

    1976-01-01

    Blood pressure and heart rate at rest in the supine and standing positions were followed before, during and after irradiation for malignant tumours in 114 patients. A statistically significant gradual reduction in blood pressure during the treatment period was established. This was more marked in older patients and in patients with higher initial blood pressure but was not related to the region irradiated or the type of tumour treated. Particularly if the patient experiences vertigo and nausea on change of position, it seems advisable to check the blood pressure during treatment. (author)

  11. Trace organic solutes in closed-loop forward osmosis applications: influence of membrane fouling and modeling of solute build-up.

    Science.gov (United States)

    D'Haese, Arnout; Le-Clech, Pierre; Van Nevel, Sam; Verbeken, Kim; Cornelissen, Emile R; Khan, Stuart J; Verliefde, Arne R D

    2013-09-15

    In this study, trace organics transport in closed-loop forward osmosis (FO) systems was assessed. The FO systems considered, consisted of an FO unit and a nanofiltration (NF) or reverse osmosis (RO) unit, with the draw solution circulating between both units. The rejection of trace organics by FO, NF and RO was tested. It was found that the rejection rates of FO were generally comparable with NF and lower than RO rejection rates. To assess the influence of fouling in FO on trace organics rejection, FO membranes were fouled with sodium alginate, bovine serum albumin or by biofilm growth, after which trace organics rejection was tested. A negative influence of fouling on FO rejection was found which was limited in most cases, while it was significant for some compounds such as paracetamol and naproxen, indicating specific compound-foulant interactions. The transport mechanism of trace organics in FO was tested, in order to differentiate between diffusive and convective transport. The concentration of trace organics in the final product water and the build-up of trace organics in the draw solution were modeled assuming the draw solution was reconcentrated by NF/RO and taking into account different transport mechanisms for the FO membrane and different rejection rates by NF/RO. Modeling results showed that if the FO rejection rate is lower than the RO rejection rate (as is the case for most compounds tested), the added value of the FO-RO cycle compared to RO only at steady-state was small for diffusively and negative for convectively transported trace organics. Modeling also showed that trace organics accumulate in the draw solution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Essential role of the electroneutral Na+-HCO3- cotransporter NBCn1 in murine duodenal acid-base balance and colonic mucus layer build-up in vivo.

    Science.gov (United States)

    Singh, Anurag Kumar; Xia, Weiliang; Riederer, Brigitte; Juric, Marina; Li, Junhua; Zheng, Wen; Cinar, Ayhan; Xiao, Fang; Bachmann, Oliver; Song, Penghong; Praetorius, Jeppe; Aalkjaer, Christian; Seidler, Ursula

    2013-04-15

    Duodenal epithelial cells need efficient defence strategies during gastric acidification of the lumen, while colonic mucosa counteracts damage by pathogens by building up a bacteria-free adherent mucus layer. Transport of HCO3(-) is considered crucial for duodenal defence against acid as well as for mucus release and expansion, but the transport pathways involved are incompletely understood. This study investigated the significance of the electroneutral Na(+)-HCO3(-) cotransporter NBCn1 for duodenal defence against acid and colonic mucus release. NBCn1 was localized to the basolateral membrane of duodenal villous enterocytes and of colonic crypt cells, with predominant expression in goblet cells. Duodenal villous enterocyte intracellular pH was studied before and during a luminal acid load by two-photon microscopy in exteriorized, vascularly perfused, indicator (SNARF-1 AM)-loaded duodenum of isoflurane-anaesthetized, systemic acid-base-controlled mice. Acid-induced HCO3(-) secretion was measured in vivo by single-pass perfusion and pH-stat titration. After a luminal acid load, NBCn1-deficient duodenocytes were unable to recover rapidly from intracellular acidification and could not respond adequately with protective HCO3(-) secretion. In the colon, build-up of the mucus layer was delayed, and a decreased thickness of the adherent mucus layer was observed, suggesting that basolateral HCO3(-) uptake is essential for optimal release of mucus. The electroneutral Na(+)-HCO3(-) cotransporter NBCn1 displays a differential cellular distribution in the murine intestine and is essential for HCO3(-)-dependent mucosal protective functions, such as recovery of intracellular pH and HCO3(-) secretion in the duodenum and secretion of mucus in the colon.

  13. Influence of light-exposure methods and depths of cavity on the microhardness of dual-cured core build-up resin composites

    Directory of Open Access Journals (Sweden)

    Keiichi YOSHIDA

    2014-01-01

    Full Text Available Objective: The purpose of this study was to evaluate the Knoop hardness number (KHN of dual-cured core build-up resin composites (DCBRCs at 6 depths of cavity after 3 post-irradiation times by 4 light-exposure methods. Material and Methods: Five specimens each of DCBRCs (Clearfil DC Core Plus [DCP] and Unifil Core EM [UCE] were filled in acrylic resin blocks with a semi-cylindrical cavity and light-cured using an LED light unit (power density: 1,000 mW/cm2at the top surface by irradiation for 20 seconds (20 s, 40 seconds (40 s, bonding agent plus 20 seconds (B+20 s, or 40 seconds plus light irradiation of both sides of each acrylic resin block for 40 seconds each (120 s. KHN was measured at depths of 0.5, 2.0, 4.0, 6.0, 8.0, and 10.0 mm at 0.5 hours, 24 hours, and 7 days post-irradiation. Statistical analysis was performed using repeated measures ANOVA and Tukey's compromise post-hoc test with a significance level of p0.05. In DCP, and not UCE, at 24 hours and 7 days post-irradiation, the B+20 s method showed significantly higher KHN at all depths of cavity, except the depth of 0.5 mm (p<0.05. Conclusion: KHN depends on the light-exposure method, use of bonding agent, depth of cavity, post-irradiation time, and material brand. Based on the microhardness behavior, DCBRCs are preferably prepared by the effective exposure method, when used for a greater depth of cavity.

  14. Soil environmental conditions and microbial build-up mediate the effect of plant diversity on soil nitrifying and denitrifying enzyme activities in temperate grasslands.

    Directory of Open Access Journals (Sweden)

    Xavier Le Roux

    Full Text Available Random reductions in plant diversity can affect ecosystem functioning, but it is still unclear which components of plant diversity (species number - namely richness, presence of particular plant functional groups, or particular combinations of these and associated biotic and abiotic drivers explain the observed relationships, particularly for soil processes. We assembled grassland communities including 1 to 16 plant species with a factorial separation of the effects of richness and functional group composition to analyze how plant diversity components influence soil nitrifying and denitrifying enzyme activities (NEA and DEA, respectively, the abundance of nitrifiers (bacterial and archaeal amoA gene number and denitrifiers (nirK, nirS and nosZ gene number, and key soil environmental conditions. Plant diversity effects were largely due to differences in functional group composition between communities of identical richness (number of sown species, though richness also had an effect per se. NEA was positively related to the percentage of legumes in terms of sown species number, the additional effect of richness at any given legume percentage being negative. DEA was higher in plots with legumes, decreased with increasing percentage of grasses, and increased with richness. No correlation was observed between DEA and denitrifier abundance. NEA increased with the abundance of ammonia oxidizing bacteria. The effect of richness on NEA was entirely due to the build-up of nitrifying organisms, while legume effect was partly linked to modified ammonium availability and nitrifier abundance. Richness effect on DEA was entirely due to changes in soil moisture, while the effects of legumes and grasses were partly due to modified nitrate availability, which influenced the specific activity of denitrifiers. These results suggest that plant diversity-induced changes in microbial specific activity are important for facultative activities such as denitrification

  15. Integral analysis of cavity pressurization in a fuel rod during an ULOF driven TOP with inclusion of surface tension effects on froth gas bubbles and variable cavity conditions due to fuel melting and ejection

    International Nuclear Information System (INIS)

    Royl, P.

    1984-02-01

    The transient cavity pressurization in an ULOF driven TOP excursion has been analyzed for the SPX-1 reactor with an equation of state that allows to simulate the contribution of small froth gas bubbles to the pressure build-up in a fuel pin with inclusion of restraints from surface tension. Calculations were performed for various bubble parameters. Estimates are made for effective gas availabilities at fuel melting which can be used in a cavity model with an ideal gas equation to arrive at similar pressure transients

  16. Multiple shell pressure vessel

    International Nuclear Information System (INIS)

    Wedellsborg, B.W.

    1988-01-01

    A method is described of fabricating a pressure vessel comprising the steps of: attaching a first inner pressure vessel having means defining inlet and outlet openings to a top flange, placing a second inner pressure vessel, having means defining inlet and outlet opening, concentric with and spaced about the first inner pressure vessel and attaching the second inner pressure vessel to the top flange, placing an outer pressure vessel, having inlet and outlet openings, concentric with and spaced apart about the second inner pressure vessel and attaching the outer pressure vessel to the top flange, attaching a generally cylindrical inner inlet conduit and a generally cylindrical inner outlet conduit respectively to the inlet and outlet openings in the first inner pressure vessel, attaching a generally cylindrical outer inlet conduit and a generally cylindrical outer outlet conduit respectively to the inlet and outlet opening in the second inner pressure vessel, heating the assembled pressure vessel to a temperature above the melting point of a material selected from the group, lead, tin, antimony, bismuth, potassium, sodium, boron and mixtures thereof, filling the space between the first inner pressure vessel and the second inner pressure vessel with material selected from the group, filling the space between the second inner pressure vessel and the outer pressure vessel with material selected from the group, and pressurizing the material filling the spaces between the pressure vessels to a predetermined pressure, the step comprising: pressurizing the spaces to a pressure whereby the wall of the first inner pressure vessel is maintained in compression during steady state operation of the pressure vessel

  17. Periodic vehicle inspection (MOT). [previously: Periodic Vehicle Inspection of cars (MOT).

    OpenAIRE

    2010-01-01

    In the 1980s the periodic vehicle inspection (MOT) of various categories of vehicles was introduced in the Netherlands. This fact sheet will discuss the legal framework of this measure and the research carried out into its effects on road safety, also in an international context. For instance, the technical conditions of cars at inspection as well as that of cars involved in crashes were studied. Tyre pressure will also be discussed in this fact sheet.

  18. Contamination of liquid oxygen by pressurized gaseous nitrogen

    Science.gov (United States)

    Zuckerwar, Allan J.; King, Tracy K.; Ngo, Kim Chi

    1989-01-01

    The penetration of pressurized gaseous nitrogen (GN2) into liquid oxygen (LOX) was investigated experimentally in the 7-inch High Temperature Tunnel, the pilot tunnel for the 8-foot High Temperature Tunnel (8'HTT) at Langley Research Center. A preliminary test using a nuclear monitor revealed the extent of the liquid nitrogen (LN2) build-up at the LOX interface as a function of GN2 pressure. Then an adaptation of the differential flash vaporization technique was used to determine the binary diffusivity of the LOX-LN2 system at a temperature of 90.2 K. The measured value D equals 0.000086 sq cm/s + or - 25 percent together with two prior measurements at lower temperatures revealed an excellent fit to the Arrhenius equation, yielding a pre-exponential factor D sub 0 equals 0.0452 sq cm/s and an activation enthalpy H equals 1.08 kcal/mol. At a pressure of 1700 psi and holding time of 15 min, the penetration of LN2 into LOX (to a 1 percent contamination level) was found to be 0.9 cm, indicating but minimal impact upon 8'HTT operations.

  19. Hypertensive crisis during pregnancy and postpartum period.

    Science.gov (United States)

    Too, Gloria T; Hill, James B

    2013-08-01

    Hypertension affects 10% of pregnancies, many with underlying chronic hypertension, and approximately 1-2% will undergo a hypertensive crisis at some point during their lives. Hypertensive crisis includes hypertensive urgency and emergency; the American College of Obstetricians and Gynecologists describes a hypertensive emergency in pregnancy as persistent (lasting 15 min or more), acute-onset, severe hypertension, defined as systolic BP greater than 160 mmHg or diastolic BP >110 mmHg in the setting of pre-eclampsia or eclampsia. Pregnancy may be complicated by hypertensive crisis, with lower blood pressure threshold for end-organ damage than non-pregnant patients. Maternal assessment should include a thorough history. Fetal assessment should include heart rate tracing, ultrasound for growth and amniotic assessment, and Doppler evaluation if growth restriction is suspected. Initial management of hypertensive emergency (systolic BP >160 mmHg or diastolic BP >110 mmHg in the setting of pre-eclampsia or eclampsia) generally includes the rapid reduction of blood pressure through the use of intravenous antihypertensive medications, with goal systolic blood pressure between 140 mmHg and 150 mmHg and diastolic pressure between 90 mmHg and 100 mmHg. First-line intravenous drugs include labetalol and hydralazine, but other agents may be used, including esmolol, nicardipine, nifedipine, and, as a last resort, sodium nitroprusside. Among patients with hypertensive urgency, slower blood pressure reduction can be provided with oral agents. The objective of this article is to review the current understanding, diagnosis, and management of hypertensive crisis during pregnancy and the postpartum period. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Periodicity, duration, and function of occupation at Tauroa Point, Northland, New Zealand

    International Nuclear Information System (INIS)

    Allen, M.S.

    2005-01-01

    Three coastal sites at Tauroa Point, Northland, New Zealand were explored using varied archaeological techniques. At least seven, and possibly more, distinct occupations were identified, the earliest dating to about the fourteenth century AD. The analysis presented here centres on defining the periodicity, duration, and nature of pre-European Maori activities on this coast over time. Geomorphic evidence, radiocarbon dates, feature characteristics, fauna and artefact assemblages, and wood charcoal data are used in this endeavour. Indications are that the earliest occupation was the most extended, followed by repeated ephemeral visits between AD 1400 and 1650, and intensified but short-term coastal occupations after AD 1650. These occupations all took place within a geomorphically active environment, yet were variably affected by erosion and aggradation; in at least one locality the build-up of dune sands intensified after site abandonment. (author). 54 refs., 17 figs., 9 tabs

  1. Some aspects of reactor pressure vessel integrity

    International Nuclear Information System (INIS)

    Korosec, D.; Vojvodic, G.J.

    1996-01-01

    Reactor pressure vessel of the pressurized water reactor nuclear power plant is the subject of extreme interest due to the fact that presents the pressure boundary of the reactor coolant system, which is under extreme thermal, mechanical and irradiation effects. Reactor pressure vessel by itself prevents the release of fission products to the environment. Design, construction and in-service inspection of such component is governed by strict ASME rules and other forms of administrative control. The reactor pressure vessel in nuclear power plant Kriko is designed and constructed in accordance with related ASME rules. The in-service inspection program includes all requests presented in ASME Code section XI. In the present article all major requests for the periodic inspections of reactor pressure vessel and fracture mechanics analysis are discussed. Detailed and strict fulfillment of all prescribed provisions guarantee the appropriate level of nuclear safety. (author)

  2. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Teens / Hypertension (High Blood Pressure) What's ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  3. Periodic feedback stabilization for linear periodic evolution equations

    CERN Document Server

    Wang, Gengsheng

    2016-01-01

    This book introduces a number of recent advances regarding periodic feedback stabilization for linear and time periodic evolution equations. First, it presents selected connections between linear quadratic optimal control theory and feedback stabilization theory for linear periodic evolution equations. Secondly, it identifies several criteria for the periodic feedback stabilization from the perspective of geometry, algebra and analyses respectively. Next, it describes several ways to design periodic feedback laws. Lastly, the book introduces readers to key methods for designing the control machines. Given its coverage and scope, it offers a helpful guide for graduate students and researchers in the areas of control theory and applied mathematics.

  4. The redoubtable ecological periodic table

    Science.gov (United States)

    Ecological periodic tables are repositories of reliable information on quantitative, predictably recurring (periodic) habitat–community patterns and their uncertainty, scaling and transferability. Their reliability derives from their grounding in sound ecological principle...

  5. Ionization chamber with build-up cup spectral sensitivity to megavoltage (0.5-20 MeV) photon fluences in free air

    International Nuclear Information System (INIS)

    Gorlachev, G.E.

    2002-01-01

    In-air measurements of photon beam properties, used in radiation therapy, is common practice for determining radiation output dependence from the field size, known as head scatter factors (HSF). PMMA and brass build-up caps are most popular miniphantoms for providing electron equilibrium. Discrepancies up to 2% in HSF measurements by different combinations of detectors and equilibrium caps have been published. One of the main reasons of those discrepancies is the detector system spectral sensitivity and differences in primary and scatter radiation spectra. In the light of new model based dose calculation methods direct radiation fluence measurement is of great interest. So, understanding of detector spectral sensitivity is important task for modern dosimetry of radiation therapy. In the present study Monte Carlo (MC) method was employed to calculate ionization chamber response to monoenergetic photon fluences, normalized to water kerma units. Simulation was done using EGS4 package. Electron transport was performed with ESTEPE equal to 4%. PEGS cross sections were generated for maximal energy 20 MeV with cutoff kinetic energy 10 KeV both for photons and electrons. Scanditronix RK-05 ionization chamber was chosen as a prototype. Eight cylindrical miniphantoms, representing four materials (PMMA, Al, Cu, Pb) and two front wall thickness, were simulated. Results are presented. Miniphantom front wall thicknesses in each case are shown in the figure. Diameter depends on the material and equal respectively: PMMA - 4, Al - 2.5, Cu - 1.5, and PB - 1.5 cm. Ionization chamber outer diameter is equal to 0.7 cm. Detector sensitivity has considerable energy dependence. Two effects explain it. First is the radiation attenuation in the miniphantom. Second is pair production, which dominates in high atomic number miniphantoms for energies above 5 MeV. Depending on the miniphantom material detector response changes from 1.5 to 5 times in the energy range from 0.5 to 20 MeV. Correct

  6. HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

    Science.gov (United States)

    Raivonen, Maarit; Smolander, Sampo; Backman, Leif; Susiluoto, Jouni; Aalto, Tuula; Markkanen, Tiina; Mäkelä, Jarmo; Rinne, Janne; Peltola, Olli; Aurela, Mika; Lohila, Annalea; Tomasic, Marin; Li, Xuefei; Larmola, Tuula; Juutinen, Sari; Tuittila, Eeva-Stiina; Heimann, Martin; Sevanto, Sanna; Kleinen, Thomas; Brovkin, Victor; Vesala, Timo

    2017-12-01

    Wetlands are one of the most significant natural sources of methane (CH4) to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2). Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH4, CO2, and oxygen (O2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O2

  7. HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

    Directory of Open Access Journals (Sweden)

    M. Raivonen

    2017-12-01

    Full Text Available Wetlands are one of the most significant natural sources of methane (CH4 to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2. Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI of aerenchymatous peatland vegetation, and water table depth (WTD, it simulates the concentrations and transport of CH4, CO2, and oxygen (O2 in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness, and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1 the model is flexible and robust and thus suitable for different environments; (2 the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3 the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular

  8. Particle-based optical pressure sensors for 3D pressure mapping.

    Science.gov (United States)

    Banerjee, Niladri; Xie, Yan; Chalaseni, Sandeep; Mastrangelo, Carlos H

    2015-10-01

    This paper presents particle-based optical pressure sensors for in-flow pressure sensing, especially for microfluidic environments. Three generations of pressure sensitive particles have been developed- flat planar particles, particles with integrated retroreflectors and spherical microballoon particles. The first two versions suffer from pressure measurement dependence on particles orientation in 3D space and angle of interrogation. The third generation of microspherical particles with spherical symmetry solves these problems making particle-based manometry in microfluidic environment a viable and efficient methodology. Static and dynamic pressure measurements have been performed in liquid medium for long periods of time in a pressure range of atmospheric to 40 psi. Spherical particles with radius of 12 μm and balloon-wall thickness of 0.5 μm are effective for more than 5 h in this pressure range with an error of less than 5%.

  9. Fracture risk assessment for the pressurized water reactor pressure vessel under pressurized thermal shock events

    International Nuclear Information System (INIS)

    Chou, Hsoung-Wei; Huang, Chin-Cheng

    2016-01-01

    Highlight: • The PTS loading conditions consistent with the USNRC's new PTS rule are applied as the loading condition for a Taiwan domestic PWR. • The state-of-the-art PFM technique is employed to analyze a reactor pressure vessel. • Novel flaw model and embrittlement correlation are considered in the study. • The RT-based regression formula of NUREG-1874 was also utilized to evaluate the failure risks of RPV. • For slightly embrittled RPV, the SO-1 type PTSs play more important role than other types of PTS. - Abstract: The fracture risk of the pressurized water reactor pressure vessel of a Taiwan domestic nuclear power plant has been evaluated according to the technical basis of the U.S.NRC's new pressurized thermal shock (PTS) screening criteria. The ORNL's FAVOR code and the PNNL's flaw models were employed to perform the probabilistic fracture mechanics analysis associated with plant specific parameters of the domestic reactor pressure vessel. Meanwhile, the PTS thermal hydraulic and probabilistic risk assessment data analyzed from a similar nuclear power plant in the United States for establishing the new PTS rule were applied as the loading conditions. Besides, an RT-based regression formula derived by the U.S.NRC was also utilized to verify the through-wall cracking frequencies. It is found that the through-wall cracking of the analyzed reactor pressure vessel only occurs during the PTS events resulted from the stuck-open primary safety relief valves that later reclose, but with only an insignificant failure risk. The results indicate that the Taiwan domestic PWR pressure vessel has sufficient structural margin for the PTS attack until either the current license expiration dates or during the proposed extended operation periods.

  10. Periodic waves in nonlinear metamaterials

    International Nuclear Information System (INIS)

    Liu, Wen-Jun; Xiao, Jing-Hua; Yan, Jie-Yun; Tian, Bo

    2012-01-01

    Periodic waves are presented in this Letter. With symbolic computation, equations for monochromatic waves are studied, and analytic periodic waves are obtained. Factors affecting properties of periodic waves are analyzed. Nonlinear metamaterials, with the continuous distribution of the dielectric permittivity obtained, are different from the ones with the discrete distribution. -- Highlights: ► Equations for the monochromatic waves in transverse magnetic polarization have been studied. ► Analytic periodic waves for the equations have been obtained. ► Periodic waves are theoretically presented and studied in the nonlinear metamaterials.

  11. Hotspots and key periods of Greenland climate change during the past six decades

    DEFF Research Database (Denmark)

    Abermann, Jakob; Hansen, Birger; Lund, Magnus

    2017-01-01

    We investigated air temperature and pressure gradients and their trends for the period 1996–2014 in Greenland and compared these to other periods since 1958. Both latitudinal temperature and pressure gradients were strongest during winter. An overall temperature increase up to 0.15 °C year−1 was ...

  12. Optimal ventilatory patterns in periodic breathing.

    Science.gov (United States)

    Ghazanshahi, S D; Khoo, M C

    1993-01-01

    The goal of this study was to determine whether periodic breathing (PB), which is highly prevalent during sleep at high altitudes, imposes physiological penalties on the respiratory system in the absence of any accompanying disease. Using a computer model of respiratory gas exchange, we compared the effects of a variety of PB patterns on the chemical and mechanical costs of breathing to those resulting from regular tidal breathing. Although PB produced considerable fluctuation in arterial blood gas tensions, for the same cycle-averaged ventilation, higher arterial oxygen saturation and lower arterial carbon dioxide levels were achieved. This result can be explained by the fact that the combination of large breaths and apnea in PB leads to a substantial reduction in dead space ventilation. At the same time, the savings in mechanical cost achieved by the respiratory muscles during apnea partially offset the increase during the breathing phase. Consequently, the "pressure cost," a criterion based on mean inspiratory pressure, was elevated only slightly, although the average work rate of breathing increased significantly. We found that, at extreme altitudes, PB patterns with clusters of 2 to 4 large breaths that alternate with apnea produce the highest arterial oxygenation levels and lowest pressure costs. The common occurrence of PB patterns with closely similar features has been reported in sleeping healthy sojourners at extreme altitudes. Taken together, these findings suggest that PB favors a reduction in the oxygen demands of the respiratory muscles and therefore may not be as detrimental as it is generally believed to be.

  13. Pressure Dome for High-Pressure Electrolyzer

    Science.gov (United States)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

  14. Nonparametric Inference for Periodic Sequences

    KAUST Repository

    Sun, Ying

    2012-02-01

    This article proposes a nonparametric method for estimating the period and values of a periodic sequence when the data are evenly spaced in time. The period is estimated by a "leave-out-one-cycle" version of cross-validation (CV) and complements the periodogram, a widely used tool for period estimation. The CV method is computationally simple and implicitly penalizes multiples of the smallest period, leading to a "virtually" consistent estimator of integer periods. This estimator is investigated both theoretically and by simulation.We also propose a nonparametric test of the null hypothesis that the data have constantmean against the alternative that the sequence of means is periodic. Finally, our methodology is demonstrated on three well-known time series: the sunspots and lynx trapping data, and the El Niño series of sea surface temperatures. © 2012 American Statistical Association and the American Society for Quality.

  15. Positive periodic solutions of delayed periodic Lotka-Volterra systems

    International Nuclear Information System (INIS)

    Lin Wei; Chen Tianping

    2005-01-01

    In this Letter, for a general class of delayed periodic Lotka-Volterra systems, we prove some new results on the existence of positive periodic solutions by Schauder's fixed point theorem. The global asymptotical stability of positive periodic solutions is discussed further, and conditions for exponential convergence are given. The conditions we obtained are weaker than the previously known ones and can be easily reduced to several special cases

  16. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    DEFF Research Database (Denmark)

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH solution O3 P is formed in a small...

  17. Pressure drops in low pressure local boiling

    International Nuclear Information System (INIS)

    Courtaud, Michel; Schleisiek, Karl

    1969-01-01

    For prediction of flow reduction in nuclear research reactors, it was necessary to establish a correlation giving the pressure drop in subcooled boiling for rectangular channels. Measurements of pressure drop on rectangular channel 60 and 90 cm long and with a coolant gap of 1,8 and 3,6 mm were performed in the following range of parameters. -) 3 < pressure at the outlet < 11 bars abs; -) 25 < inlet temperature < 70 deg. C; -) 200 < heat flux < 700 W/cm 2 . It appeared that the usual parameter, relative length in subcooled boiling, was not sufficient to correlate experimental pressure losses on the subcooled boiling length and that there was a supplementary influence of pressure, heat flux and subcooling. With an a dimensional parameter including these terms a correlation was established with an error band of ±10%. With a computer code it was possible to derive the relation giving the overall pressure drop along the channel and to determine the local gradients of pressure drop. These local gradients were then correlated with the above parameter calculated in local conditions. 95 % of the experimental points were computed with an accuracy of ±10% with this correlation of gradients which can be used for non-uniform heated channels. (authors) [fr

  18. High-pressure portable pneumatic drive unit.

    Science.gov (United States)

    Hete, B F; Savage, M; Batur, C; Smith, W A; Golding, L A; Nosé, Y

    1989-12-01

    The left ventricular assist device (LVAD) of the Cleveland Clinic Foundation (CCF) is a single-chamber assist pump, driven by a high-pressure pneumatic cylinder. A low-cost, portable driver that will allow cardiac care patients, with a high-pressure pneumatic ventricle assist, more freedom of movement has been developed. The compact and light-weight configuration can provide periods of 2 h of freedom from a fixed position driver and does not use exotic technology.

  19. From Periodic Properties to a Periodic Table Arrangement

    Science.gov (United States)

    Besalú, Emili

    2013-01-01

    A periodic table is constructed from the consideration of periodic properties and the application of the principal components analysis technique. This procedure is useful for objects classification and data reduction and has been used in the field of chemistry for many applications, such as lanthanides, molecules, or conformers classification.…

  20. Periodic instantons and scattering amplitudes

    International Nuclear Information System (INIS)

    Khlebnikov, S.Yu.; Rubakov, V.A.; Tinyakov, P.G.

    1991-04-01

    We discuss the role of periodic euclidean solutions with two turning points and zero winding number (periodic instantons) in instanton induced processes below the sphaleron energy E sph . We find that the periodic instantons describe certain multiparticle scattering events leading to the transitions between topologically distinct vacua. Both the semiclassical amplitudes and inital and final states of these transitions are determined by the periodic instantons. Furthermore, the corresponding probabilities are maximal among all states of given energy. We show that at E ≤ E sph , the periodic instantons can be approximated by infinite chains of ordinary instantons and anti-instantons, and they naturally emerge as deformations of the zero energy instanton. In the framework of 2d abelian Higgs model and 4d electroweak theory we show, however, that there is not obvious relation between periodic instantons and two-particle scattering amplitudes. (orig.)

  1. Real time control of the sawtooth period using EC launchers

    International Nuclear Information System (INIS)

    Paley, J I; Felici, F; Coda, S; Goodman, T P; Piras, F

    2009-01-01

    Tokamak plasmas operating at high performance are limited by several MHD instabilities. The sawtooth instability limits the core plasma pressure and can drive the neoclassical tearing mode unstable, but also prevents accumulation of impurities in the core. Electron cyclotron heating and current drive systems can be used to modify the local current profile and therefore tailor the sawtooth period. This paper reports on demonstrations of continuous real time feedback control of the sawtooth period by varying the EC injection angle.

  2. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... L Sarah Harrison, OT Anne Bryden, OT The Role of the Social Worker after Spinal Cord Injury ... do to prevent pressure sores? play_arrow What role does diet and hydration play in preventing pressure ...

  3. Atmospheric Pressure Indicator.

    Science.gov (United States)

    Salzsieder, John C.

    1995-01-01

    Discusses observable phenomena related to air pressure. Describes a simple, unobtrusive, semiquantitative device to monitor the changes in air pressure that are associated with altitude, using a soft-drink bottle and a balloon. (JRH)

  4. Blood Pressure Medicines

    Science.gov (United States)

    High blood pressure, also called hypertension, usually has no symptoms. But it can cause serious problems such as stroke, heart ... kidney failure. If you cannot control your high blood pressure through lifestyle changes such as losing weight and ...

  5. High blood pressure - adults

    Science.gov (United States)

    ... pressure is found. This is called essential hypertension. High blood pressure that is caused by another medical condition or medicine you are taking is called secondary hypertension. Secondary hypertension may be due to: Chronic ...

  6. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Injury Medical Expert Videos Topics menu Topics Preventing Pressure Sores Adult Injuries Spinal Cord Injury 101 David Chen, MD Preventing Pressure Sores Mary Zeigler, MS Transition from Hospital to Home ...

  7. Preventing Pressure Sores

    Science.gov (United States)

    ... and how can it be increased? play_arrow What do family members and caregivers need to know about pressure sores? play_arrow What do family members and caregivers need to do to prevent pressure sores? play_ ...

  8. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  9. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... play_arrow What do family members and caregivers need to know about pressure sores? play_arrow What do family members and caregivers need to do to prevent pressure sores? play_arrow ...

  10. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... increased? play_arrow What do family members and caregivers need to know about pressure sores? play_arrow What do family members and caregivers need to do to prevent pressure sores? play_ ...

  11. High blood pressure - children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007696.htm High blood pressure - children To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  12. Preventing High Blood Pressure

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

  13. High blood pressure - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007329.htm High blood pressure - infants To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  14. High blood pressure medications

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

  15. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... especially prone to pressure sores? play_arrow What parts of the body are most likely to develop ... play_arrow How long is the typical healing time for a pressure sore? play_arrow Why do ...

  16. Holonomic systems for period mappings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jingyue, E-mail: jychen@brandeis.edu [Department of Mathematics, Brandeis University, Waltham, MA 02454 (United States); Huang, An, E-mail: anhuang@math.harvard.edu [Department of Mathematics, Harvard University, Cambridge, MA 02138 (United States); Lian, Bong H., E-mail: lian@brandeis.edu [Department of Mathematics, Brandeis University, Waltham, MA 02454 (United States)

    2015-09-15

    Period mappings were introduced in the sixties [4] to study variation of complex structures of families of algebraic varieties. The theory of tautological systems was introduced recently [7,8] to understand period integrals of algebraic manifolds. In this paper, we give an explicit construction of a tautological system for each component of a period mapping. We also show that the D-module associated with the tautological system gives rise to many interesting vanishing conditions for period integrals at certain special points of the parameter space.

  17. Microprocessor controlled digital period meter

    International Nuclear Information System (INIS)

    Keefe, D.J.; McDowell, W.P.; Rusch, G.K.

    1980-01-01

    A microprocessor controlled digital period meter has been developed and tested operationally on a reactor at Argonne National Laboratory. The principle of operation is the mathematical relationship between asymptotic periods and pulse counting circuitry. This relationship is used to calculate and display the reactor periods over a range of /plus or minus/1 second to /plus or minus/999 seconds. The time interval required to update each measurement automatically varies from 8 seconds at the lowest counting rates to 2 seconds at higher counting rates. The paper will describe hardware and software design details and show the advantages of this type of Period Meter over the conventional circuits. 1 ref

  18. High pressure X-ray studies

    International Nuclear Information System (INIS)

    Sikka, S.K.

    1981-01-01

    High pressure research has already led to new insights in the physical properties of materials and at times to the synthesis of new ones. In all this, X-ray diffraction has been a valuable diagnostic experimental tool. In particular, X-rays in high pressure field have been used (a) for crystallographic identification of high pressure polymorphs and (b) for study of the effect of pressure on lattice parameters and volume under isothermal conditions. The results in the area (a) are reviewed. The techniques of applying high pressures are described. These include both static and dynamic shockwave X-ray apparatus. To illustrate the effect of pressure, some of the pressure induced phase transitions in pure metals are described. It has been found that there is a clear trend for elements in any group of the periodic table to adopt similar structures at high pressures. These studies have enabled to construct generalized phase diagrams for many groups. In the case of alloys, the high pressure work done on Ti-V alloys is presented. (author)

  19. High-pressure microbiology

    National Research Council Canada - National Science Library

    Michiels, Chris; Bartlett, Douglas Hoyt; Aertsen, Abram

    2008-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. High Hydrostatic Pressure Effects in the Biosphere: from Molecules to Microbiology * Filip Meersman and Karel Heremans . . . . . . . . . . . . 2. Effects...

  20. Design and Evaluation of a Pressure and Temperature Monitoring System for Pressure Ulcer Prevention

    Directory of Open Access Journals (Sweden)

    Farve Daneshvar Fard

    2014-08-01

    Full Text Available Introduction Pressure ulcers are tissue damages resulting from blood flow restriction, which occurs when the tissue is exposed to high pressure for a long period of time. These painful sores are common in patients and elderly, who spend extended periods of time in bed or wheelchair. In this study, a continuous pressure and temperature monitoring system was developed for pressure ulcer prevention. Materials and Methods The monitoring system consists of 64 pressure and 64 temperature sensors on a 40×50 cm2 sheet. Pressure and temperature data and the corresponding maps were displayed on a computer in real-time. Risk assessment could be performed by monitoring and recording absolute pressure and temperature values, as well as deviations over time. Furthermore, a posture detection procedure was proposed for sitting posture identification. Information about the patient’s movement history may help caregivers make informed decisions about the patient’s repositioning and ulcer prevention strategies. Results Steady temporal behaviour of the designed system and repeatability of the measurements were evaluated using several particular tests. The results illustrated that the system could be utilized for continuous monitoring of interface pressure and temperature for pressure ulcer prevention. Furthermore, the proposed method for detecting sitting posture was verified using a statistical analysis. Conclusion A continuous time pressure and temperature monitoring system was presented in this study. This system may be suited for pressure ulcer prevention given its feasibility for simultaneous monitoring of pressure and temperature and alarming options. Furthermore, a method for detecting different sitting postures was proposed and verified. Pressure ulcers in wheelchair-bound patients may be prevented using this sitting posture detection method.