Energy Technology Data Exchange (ETDEWEB)
Lechner, J. [Forschungsinstitut fuer Geodaesie, Topographie und Kartographie, Zdiby (Czechoslovakia)
1996-12-31
The contribution describes hydrostatic stationary measuring systems for measurements of height variations of a turbine unit. The measuring system developed at the research institute and the algorithms for calibration, measurement and evaluation are presented. Measurements were made on a 500 MW turbogenerator unit at different states of operation. (orig.) [Deutsch] Der Beitrag enthaelt eine kurze Uebersicht ueber die hydrostatischen stationaeren Messsysteme fuer das Gebiet der Messung der Hoehenaenderung eines Grossturbinentisches. Es wird das automatische stationaere hydrostatische Messsystem, das im Forschungsinstitut entwickelt wurde, der Algorithmus der Kalibrierung, der Messung und der Auswertung der Messergebnisse vorgestellt. Es wird das Messergebnis der Vertikalverschiebungen der Konstruktion des Turbogenerators mit der Leistung 500 Megawatt bei seinem verschiedenen Betriebszustand angefuehrt. (orig.)
Directory of Open Access Journals (Sweden)
Qinghua Liu
2014-12-01
Full Text Available Traffic congestion is a growing problem in urban areas all over the world. The transport sector has been in full swing event study on intelligent transportation system for automatic detection. The functionality of automatic incident detection on expressways is a primary objective of advanced traffic management system. In order to save lives and prevent secondary incidents, accurate and prompt incident detection is necessary. This paper presents a methodology that integrates moving average (MA model with stationary wavelet decomposition for automatic incident detection, in which parameters of layer coefficient are extracted from the difference between the upstream and downstream occupancy. Unlike other wavelet-based method presented before, firstly it smooths the raw data with MA model. Then it uses stationary wavelet to decompose, which can achieve accurate reconstruction of the signal, and does not shift the signal transfer coefficients. Thus, it can detect the incidents more accurately. The threshold to trigger incident alarm is also adjusted according to normal traffic condition with congestion. The methodology is validated with real data from Tokyo Expressway ultrasonic sensors. Experimental results show that it is accurate and effective, and that it can differentiate traffic accident from other condition such as recurring traffic congestion.
Niemi, Antti H.
2013-12-01
We investigate the application of the discontinuous Petrov-Galerkin (DPG) finite element framework to stationary convection-diffusion problems. In particular, we demonstrate how the quasi-optimal test space norm improves the robustness of the DPG method with respect to vanishing diffusion. We numerically compare coarse-mesh accuracy of the approximation when using the quasi-optimal norm, the standard norm, and the weighted norm. Our results show that the quasi-optimal norm leads to more accurate results on three benchmark problems in two spatial dimensions. We address the problems associated to the resolution of the optimal test functions with respect to the quasi-optimal norm by studying their convergence numerically. In order to facilitate understanding of the method, we also include a detailed explanation of the methodology from the algorithmic point of view. © 2013 Elsevier Ltd. All rights reserved.
Niemi, Antti H; Calo, Victor M
2012-01-01
We investigate the application of the discontinuous Petrov-Galerkin (DPG) finite element framework to stationary convection-diffusion problems. In particular, we demonstrate how the quasi-optimal test space norm can be utilized to improve the robustness of the DPG method with respect to vanishing diffusion. We numerically compare coarse-mesh accuracy of the approximation when using the quasi-optimal norm, the standard norm, and the weighted norm. Our results show that the quasi-optimal norm leads to more accurate results on three benchmark problems in two spatial dimensions. We address the problems associated to the resolution of the optimal test functions with respect to the quasi-optimal norm by studying their convergence numerically. In order to facilitate understanding of the method, we also include a detailed explanation of the methodology from the algorithmic point of view.
Hydrostatic transmission design
Dalda Rivas, Ignacio
2009-01-01
This project treats the analysis of the hydrostatic transmission dynamic properties using a simulation model, which has been done with the simulation program AMESim. That simulation has been the main work in the project, especially because it is a good way to understand how a hydrostatic transmission works. The hydrostatic transmission are used in heavy vehicles such as earth moving machines, agriculture machines, forest machines, industrial and mining lifters. Nowadays, the demand of that...
Directory of Open Access Journals (Sweden)
Matviychuk K.S.
2012-06-01
Full Text Available The conditions of technical stability by measure of the dynamical states of the non-stationary control systems with variable structure are investigated in presence of filtration process of the control signals. The suitable systems of the differential equations have the changing coefficients, which are altering in time and by jumplike together with jumplike changing of the control function of the process and with simultaneous jumplike changing at the direction of the suitable phase velocity vector of the process. The criteria of technical stability by measure on finite and infinite intervals of time, asymptotical technical stability by measure, and also the criterion of the technical instability by measure of given, inwardly dependent on quality of filtering of control signals of non-stationary dynamical systems with variable structure are determiner under base of the differential inequalities method at combination with properties of the class of the absolutely positive functions, for all feasible initial disturbances from the pre-assigned by measure set of initial states of the process.
Slurry pipeline hydrostatic testing
Energy Technology Data Exchange (ETDEWEB)
Betinol, Roy G.; Navarro Rojas, Luis Alejandro [BRASS Chile S.A., Santiago (Chile)
2009-07-01
The transportation of concentrates and tailings through long distance pipeline has been proven in recent years to be the most economic, environmentally friendly and secure means of transporting of mine products. This success has led to an increase in the demand for long distance pipeline throughout the mining industry. In year 2007 alone, a total of over 500 km of pipeline has been installed in South America alone and over 800 km are in the planning stages. As more pipelines are being installed, the need to ensure its operating integrity is ever increasing. Hydrostatic testing of long distance pipeline is one of the most economical and expeditious way to proving the operational integrity of the pipe. The intent of this paper is to show the sound reasoning behind construction hydro testing and the economic benefit it presents. It will show how hydro test pressures are determined based on ASME B31.11 criteria. (author)
46 CFR 64.83 - Hydrostatic test.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Hydrostatic test. 64.83 Section 64.83 Shipping COAST... HANDLING SYSTEMS Periodic Inspections and Tests of MPTs § 64.83 Hydrostatic test. (a) The hydrostatic test..., the heating coil passing a hydrostatic test at a pressure of 200 psig or more or 50 percent or...
Scientific Evidence for Hydrostatic Shock
Courtney, Michael; Courtney, Amy
2008-01-01
This paper reviews the scientific support for a ballistic pressure wave radiating outward from a penetrating projectile and causing injury and incapacitation. This phenomenon is known colloquially as "hydrostatic shock." The idea apparently originates with Col. Frank Chamberlin, a World War II trauma surgeon and wound ballistics researcher. The paper reviews claims that hydrostatic shock is a myth and considers supporting evidence through parallels with blast, describing the physics of the pr...
Scientific Evidence for Hydrostatic Shock
Courtney, Michael
2008-01-01
This paper reviews the scientific support for a ballistic pressure wave radiating outward from a penetrating projectile and causing injury and incapacitation. This phenomenon is known colloquially as "hydrostatic shock." The idea apparently originates with Col. Frank Chamberlin, a World War II trauma surgeon and wound ballistics researcher. The paper reviews claims that hydrostatic shock is a myth and considers supporting evidence through parallels with blast, describing the physics of the pressure wave, evidence for remote cerebral effects, and remote effects in the spine and other internal organs. Finally, the review considers the levels of energy transfer required for the phenomenon to be readily observed.
Hydrostatic and hybrid bearing design
Rowe, W B
1983-01-01
Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des
Metal extrusion using hydrostatic pressures
International Nuclear Information System (INIS)
The main problems connected with the deformation of metals due to extrusion are described. A method is put forward for calculating the rational rate of percentage deformation in the case of bar extrusion using a cylindrical container; reference is made to previous work on extrusion using a hydrostatic pressure with or without back-pressure. An extrusion process is described using hydrostatic pressure, without back-pressure, and using the lubricant for transmitting the thrust. This process has been used for eight years by the C.E.A. for the extrusion of a very wide range of metals, from beryllium to uranium and including steels; it leads to excellent surface textures. A very fine crystallization can be obtained on extruded products when the rate of extrusion is very low. There appears to be nothing against the use of high extrusion rates using this method. (author)
Reliability of a hydrostatic bearing
CHARKI, Abderafi; DIOP, Khadim; CHAMPMARTIN, Stéphane; AMBARI, Abdelhak
2013-01-01
This paper presents a methodology for evaluating the failure probability of fluid bearings, which are sensitive components for the design of machine rotors, mechatronic systems, and high precision metrology. The static and dynamic behavior of a fluid bearing depends on several parameters, such as external load, bearing dimensions, supply pressure, quality of the machined surfaces, fluid properties, etc. In this paper, the characteristics of a simple geometry hydrostatic bearing are calculated...
ANSYS Modeling of Hydrostatic Stress Effects
Allen, Phillip A.
1999-01-01
Classical metal plasticity theory assumes that hydrostatic pressure has no effect on the yield and postyield behavior of metals. Plasticity textbooks, from the earliest to the most modem, infer that there is no hydrostatic effect on the yielding of metals, and even modem finite element programs direct the user to assume the same. The object of this study is to use the von Mises and Drucker-Prager failure theory constitutive models in the finite element program ANSYS to see how well they model conditions of varying hydrostatic pressure. Data is presented for notched round bar (NRB) and "L" shaped tensile specimens. Similar results from finite element models in ABAQUS are shown for comparison. It is shown that when dealing with geometries having a high hydrostatic stress influence, constitutive models that have a functional dependence on hydrostatic stress are more accurate in predicting material behavior than those that are independent of hydrostatic stress.
A high-order staggered finite-element vertical discretization for non-hydrostatic atmospheric models
Guerra, Jorge E.; Ullrich, Paul A.
2016-06-01
Atmospheric modeling systems require economical methods to solve the non-hydrostatic Euler equations. Two major differences between hydrostatic models and a full non-hydrostatic description lies in the vertical velocity tendency and numerical stiffness associated with sound waves. In this work we introduce a new arbitrary-order vertical discretization entitled the staggered nodal finite-element method (SNFEM). Our method uses a generalized discrete derivative that consistently combines the discontinuous Galerkin and spectral element methods on a staggered grid. Our combined method leverages the accurate wave propagation and conservation properties of spectral elements with staggered methods that eliminate stationary (2Δx) modes. Furthermore, high-order accuracy also eliminates the need for a reference state to maintain hydrostatic balance. In this work we demonstrate the use of high vertical order as a means of improving simulation quality at relatively coarse resolution. We choose a test case suite that spans the range of atmospheric flows from predominantly hydrostatic to nonlinear in the large-eddy regime. Our results show that there is a distinct benefit in using the high-order vertical coordinate at low resolutions with the same robust properties as the low-order alternative.
On hydrostatic flows in isentropic coordinates
Bokhove, Onno
2000-01-01
The hydrostatic primitive equations of motion which have been used in large-scale weather prediction and climate modelling over the last few decades are analysed with variational methods in an isentropic Eulerian framework. The use of material isentropic coordinates for the Eulerian hydrostatic equa
Generalized stationary phase approximations for mountain waves
Knight, H.; Broutman, D.; Eckermann, S. D.
2016-04-01
Large altitude asymptotic approximations are derived for vertical displacements due to mountain waves generated by hydrostatic wind flow over arbitrary topography. This leads to new asymptotic analytic expressions for wave-induced vertical displacement for mountains with an elliptical Gaussian shape and with the major axis oriented at any angle relative to the background wind. The motivation is to understand local maxima in vertical displacement amplitude at a given height for elliptical mountains aligned at oblique angles to the wind direction, as identified in Eckermann et al. ["Effects of horizontal geometrical spreading on the parameterization of orographic gravity-wave drag. Part 1: Numerical transform solutions," J. Atmos. Sci. 72, 2330-2347 (2015)]. The standard stationary phase method reproduces one type of local amplitude maximum that migrates downwind with increasing altitude. Another type of local amplitude maximum stays close to the vertical axis over the center of the mountain, and a new generalized stationary phase method is developed to describe this other type of local amplitude maximum and the horizontal variation of wave-induced vertical displacement near the vertical axis of the mountain in the large altitude limit. The new generalized stationary phase method describes the asymptotic behavior of integrals where the asymptotic parameter is raised to two different powers (1/2 and 1) rather than just one power as in the standard stationary phase method. The vertical displacement formulas are initially derived assuming a uniform background wind but are extended to accommodate both vertical shear with a fixed wind direction and vertical variations in the buoyancy frequency.
Railcar waste transfer system hydrostatic test
International Nuclear Information System (INIS)
Recent modifications have been performed on the T-Plant Railcar Waste Transfer System, This Acceptance Test Procedure (ATP) has been prepared to demonstrate that identified piping welds and mechanical connections incorporated during the modification are of high integrity and are acceptable for service. This will be achieved by implementation of a hydrostatic leak test
Railcar waste transfer system hydrostatic test report
International Nuclear Information System (INIS)
This Acceptance Test Report (ATR) documents for record purposes the field results, acceptance, and approvals of the completed acceptance test per HNF-SD-W417-ATP-001, ''Rail car Waste Transfer System Hydrostatic Test''. The test was completed and approved without any problems or exceptions
A Load Cell for Hydrostatic Weighing
Fahey, Thomas D.; Schroeder, Richard
1978-01-01
Although a load cell is more expensive than the autopsy scale for hydrostatic weighing, it is more accurate, easier to read, has no moving parts, is less susceptible to rust, and is less likely to be damaged by large subjects exceeding its capacity. (Author)
49 CFR 230.36 - Hydrostatic testing of boilers.
2010-10-01
... Appurtenances Pressure Testing of Boilers § 230.36 Hydrostatic testing of boilers. (a) Time of test. The... following any hydrostatic test where the pressure exceeds MAWP. ... 49 Transportation 4 2010-10-01 2010-10-01 false Hydrostatic testing of boilers. 230.36 Section...
49 CFR 178.605 - Hydrostatic pressure test.
2010-10-01
... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Testing of Non-bulk Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be conducted for the qualification of all metal, plastic, and...
46 CFR 154.562 - Cargo hose: Hydrostatic test.
2010-10-01
... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo hose: Hydrostatic test. 154.562 Section 154.562 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Hose § 154.562 Cargo hose: Hydrostatic test. Each cargo hose must pass a hydrostatic pressure test...
46 CFR 61.30-10 - Hydrostatic test.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Hydrostatic test. 61.30-10 Section 61.30-10 Shipping... INSPECTIONS Tests and Inspections of Fired Thermal Fluid Heaters § 61.30-10 Hydrostatic test. All new installations of thermal fluid heaters must be given a hydrostatic test of 11/2 times the maximum...
Haeseler, Friedrich
2003-01-01
Automatic sequences are sequences which are produced by a finite automaton. Although they are not random they may look as being random. They are complicated, in the sense of not being not ultimately periodic, they may look rather complicated, in the sense that it may not be easy to name the rule by which the sequence is generated, however there exists a rule which generates the sequence. The concept automatic sequences has special applications in algebra, number theory, finite automata and formal languages, combinatorics on words. The text deals with different aspects of automatic sequences, in particular:· a general introduction to automatic sequences· the basic (combinatorial) properties of automatic sequences· the algebraic approach to automatic sequences· geometric objects related to automatic sequences.
Mapping Initial Hydrostatic Models in Godunov Codes
Zingale, M.; Dursi, L. J.; ZuHone, J.; Calder, A. C.; Fryxell, B.; Plewa, T.; Truran, J. W.; Caceres, A; Olson, K; Ricker, P. M.; Riley, K.; Rosner, R.; Siegel, A.; Timmes, F. X.; Vladimirova, N.
2002-01-01
We look in detail at the process of mapping an astrophysical initial model from a stellar evolution code onto the computational grid of an explicit, Godunov type code while maintaining hydrostatic equilibrium. This mapping process is common in astrophysical simulations, when it is necessary to follow short-timescale dynamics after a period of long timescale buildup. We look at the effects of spatial resolution, boundary conditions, the treatment of the gravitational source terms in the hydrod...
History and evidence regarding hydrostatic shock
Courtney, Michael; Courtney, Amy
2011-01-01
This paper reviews the history and evidence related to remote wounding effects of ballistic pressure waves imparted to tissue by the impact of a bullet. Such remote effects are often referred to as hydraulic or hydrostatic shock. In spite of considerable published evidence and a long history, some medical professionals continue to regard the ability of a bullet to injure tissue that is not directly crushed or stretched as mythical (Jandial R, Reichwage B, Levy M, Duenas V, Sturdivan L. Ballis...
Structural and Hydrostatic Analysis of Deployment Vessel
Flink, Oskar; Holmberg, Tommy
2015-01-01
This research investigates the structural and hydrostatic stability of a barge of two different designs used for deploying wave energy converters (WECs) developed at Uppsala University. The key points examined are structural design, static stability and deployment strategy for WECs. This kind of research is needed for every unique design of a floating vessel to ensure the safety of the vessel. To design vessels and to simulate their structural stability, Solidworks 2014 has been used. The sta...
Hydrostatic compression in glycerinated rabbit muscle fibers.
Ranatunga, K.W.; Fortune, N S; Geeves, M A
1990-01-01
Glycerinated muscle fibers isolated from rabbit psoas muscle, and a number of other nonmuscle elastic fibers including glass, rubber, and collagen, were exposed to hydrostatic pressures of up to 10 MPa (100 Atm) to determine the pressure sensitivity of their isometric tension. The isometric tension of muscle fibers in the relaxed state (passive tension) was insensitive to increased pressure, whereas the muscle fiber tension in rigor state increased linearly with pressure. The tension of all o...
Mapping Initial Hydrostatic Models in Godunov Codes
Zingale, M A; Zu Hone, J; Calder, A C; Fryxell, B; Plewa, T; Truran, J W; Caceres, A; Olson, K; Ricker, P M; Riley, K; Rosner, R; Siegel, A; Timmes, F X; Vladimirova, N
2002-01-01
We look in detail at the process of mapping an astrophysical initial model from a stellar evolution code onto the computational grid of an explicit, Godunov type code while maintaining hydrostatic equilibrium. This mapping process is common in astrophysical simulations, when it is necessary to follow short-timescale dynamics after a period of long timescale buildup. We look at the effects of spatial resolution, boundary conditions, the treatment of the gravitational source terms in the hydrodynamics solver, and the initialization process itself. We conclude with a summary detailing the mapping process that yields the lowest ambient velocities in the mapped model.
Hydrostatic, aerostatic and hybrid bearing design
Rowe, W Brian
2012-01-01
Solve your bearing design problems with step-by-step procedures and hard-won performance data from a leading expert and consultant Compiled for ease of use in practical design scenarios, Hydrostatic, Aerostatic and Hybrid Bearing Design provides the basic principles, design procedures and data you need to create the right bearing solution for your requirements. In this valuable reference and design companion, author and expert W. Brian Rowe shares the hard-won lessons and figures from a lifetime's research and consultancy experience. Coverage includes: Clear e
Ceramic stationary gas turbine
Energy Technology Data Exchange (ETDEWEB)
Roode, M. van [Solar Turbines Inc., San Diego, CA (United States)
1995-10-01
The performance of current industrial gas turbines is limited by the temperature and strength capabilities of the metallic structural materials in the engine hot section. Because of their superior high-temperature strength and durability, ceramics can be used as structural materials for hot section components (blades, nozzles, combustor liners) in innovative designs at increased turbine firing temperatures. The benefits include the ability to increase the turbine inlet temperature (TIT) to about 1200{degrees}C ({approx}2200{degrees}F) or more with uncooled ceramics. It has been projected that fully optimized stationary gas turbines would have a {approx}20 percent gain in thermal efficiency and {approx}40 percent gain in output power in simple cycle compared to all metal-engines with air-cooled components. Annual fuel savings in cogeneration in the U.S. would be on the order of 0.2 Quad by 2010. Emissions reductions to under 10 ppmv NO{sub x} are also forecast. This paper describes the progress on a three-phase, 6-year program sponsored by the U.S. Department of Energy, Office of Industrial Technologies, to achieve significant performance improvements and emissions reductions in stationary gas turbines by replacing metallic hot section components with ceramic parts. Progress is being reported for the period September 1, 1994, through September 30, 1995.
International Nuclear Information System (INIS)
This report describes the comparison of stationary and non-stationary geostatistical models for the purpose of inferring block-scale hydraulic conductivity values from packer tests at Aespoe. The comparison between models is made through the evaluation of cross-validation statistics for three experimental designs. The first experiment consisted of a 'Delete-1' test previously used at Finnsjoen. The second test consisted of 'Delete-10%' and the third test was a 'Delete-50%' test. Preliminary data analysis showed that the 3 m and 30 m packer test data can be treated as a sample from a single population for the purposes of geostatistical analyses. Analysis of the 3 m data does not indicate that there are any systematic statistical changes with depth, rock type, fracture zone vs non-fracture zone or other mappable factor. Directional variograms are ambiguous to interpret due to the clustered nature of the data, but do not show any obvious anisotropy that should be accounted for in geostatistical analysis. Stationary analysis suggested that there exists a sizeable spatially uncorrelated component ('Nugget Effect') in the 3 m data, on the order of 60% of the observed variance for the various models fitted. Four different nested models were automatically fit to the data. Results for all models in terms of cross-validation statistics were very similar for the first set of validation tests. Non-stationary analysis established that both the order of drift and the order of the intrinsic random functions is low. This study also suggests that conventional cross-validation studies and automatic variogram fitting are not necessarily evaluating how well a model will infer block scale hydraulic conductivity values. 20 refs, 20 figs, 14 tabs
Käppeli, R.; Mishra, S.
2016-03-01
Context. Many problems in astrophysics feature flows which are close to hydrostatic equilibrium. However, standard numerical schemes for compressible hydrodynamics may be deficient in approximating this stationary state, where the pressure gradient is nearly balanced by gravitational forces. Aims: We aim to develop a second-order well-balanced scheme for the Euler equations. The scheme is designed to mimic a discrete version of the hydrostatic balance. It therefore can resolve a discrete hydrostatic equilibrium exactly (up to machine precision) and propagate perturbations, on top of this equilibrium, very accurately. Methods: A local second-order hydrostatic equilibrium preserving pressure reconstruction is developed. Combined with a standard central gravitational source term discretization and numerical fluxes that resolve stationary contact discontinuities exactly, the well-balanced property is achieved. Results: The resulting well-balanced scheme is robust and simple enough to be very easily implemented within any existing computer code that solves time explicitly or implicitly the compressible hydrodynamics equations. We demonstrate the performance of the well-balanced scheme for several astrophysically relevant applications: wave propagation in stellar atmospheres, a toy model for core-collapse supernovae, convection in carbon shell burning, and a realistic proto-neutron star.
International Nuclear Information System (INIS)
This booklet describes a series of administrative procedures regarding the code of practice in Alberta for the release of hydrostatic test water from hydrostatic testing of petroleum liquid and gas pipelines. The topics covered include the registration process, the type and quality of water to use during the test, and the analytical methods to be used. Reporting schedule and record keeping information are also covered. Schedule 1 discusses the requirements for the release of hydrostatic test water to land, while Schedule 2 describes the requirements for the release of hydrostatic test water to receiving water. 3 tabs
Stationary and Transient Response Statistics
DEFF Research Database (Denmark)
Madsen, Peter Hauge; Krenk, Steen
1982-01-01
The covariance functions for the transient response of a linear MDOF-system due to stationary time limited excitation with an arbitrary frequency content are related directly to the covariance functions of the stationary response. For rational spectral density functions closed form expressions fo...
Computer simulations of 3C-SiC under hydrostatic and non-hydrostatic stresses.
Guedda, H Z; Ouahrani, T; Morales-García, A; Franco, R; Salvadó, M A; Pertierra, P; Recio, J M
2016-03-01
The response of 3C-SiC to hydrostatic pressure and to several uni- and bi-axial stress conditions is thoroughly investigated using first principles calculations. A topological interpretation of the chemical bonding reveals that the so-called non-covalent interactions enhance only at high pressure while the nature of the covalent Si-C bonding network keeps essentially with the same pattern. The calculated low compressibility agrees well with experimental values and is in concordance with the high structural stability of this polymorph under hydrostatic pressure. Under uniaxial [001] stress, the c/a ratio shows a noticeable drop inducing a closure of the band gap and the emergence of a metallic state around 40 GPa. This behavior correlates with a plateau of the electron localization function exhibiting a roughly constant and non-negligible value surrounding CSi4 and SiC4 covalent bonded units. PMID:26922870
History and evidence regarding hydrostatic shock
Courtney, Michael; 10.1227/NEU.0b013e3182041992
2011-01-01
This paper reviews the history and evidence related to remote wounding effects of ballistic pressure waves imparted to tissue by the impact of a bullet. Such remote effects are often referred to as hydraulic or hydrostatic shock. In spite of considerable published evidence and a long history, some medical professionals continue to regard the ability of a bullet to injure tissue that is not directly crushed or stretched as mythical (Jandial R, Reichwage B, Levy M, Duenas V, Sturdivan L. Ballistics for the neurosurgeon. Neurosurgery. 2008:62:472-480.) Early references to these effects date to the 19th century; however, compelling experimental support and medical findings in human case studies did not become available until the late 20th and early 21st century.
Energy Technology Data Exchange (ETDEWEB)
Kalmbach, K.
2001-07-01
The product range of the rail vehicle industry comprises the construction of railroad material for long-distance and short-distance transport. This includes, for example, locomotives and cars, subway, light railway and tramway cars as well as rail vehicle equipment. The development of the industry is determined by the demand for transport services and government actions for the extension of railways and procurement of suitable vehicle types. In contrast to road vehicles, differential gears are only used in a negligible percentage of rail vehicles. Primarily in the short-distance rail transport sector, the demand for differential gears is growing due to increased drive power, smaller wheel diameters, lower vehicle mass with higher load capacity, the introduction of low-floor technology as well as the requirement of employing ever more quiet vehicles. In hydrostatic self-locking differential gears, oil is supplied to the gears within the differential gearbox. They only rotate relative to each other when the differential gear performs a compensation movement. In this case, oil is transported in the tooth space to the meshing of the gears, where it is displaced due to the meshing and must drain through tight gaps. The pressure generated by this process acts against the compensation movement of the gear, and the drive torque is transmitted to the wheel that has the higher friction. The achievable locking torque is linearly dependent on the differential speed of the drive wheel. This locking effect is achieved without wear-prone components and works automatically without active external intervention. The design space required corresponds to that of conventional differential gears, as the locking effect is integrated in the existing design. (orig.)
Calibration of capacitive hydrostatic leveling sensors of NSRL
International Nuclear Information System (INIS)
The principle of capacitive hydrostatic leveling sensors was presented. Simulations of sensors with two kinds of materials (metal and distilled water) as target electrode in the situations of calibration and work were carried out by Ansoft Maxwell software. Different values of capacitances in different situations were compared and analyzed. Then some experiments were done with independently developed prototype of capacitive hydrostatic leveling sensors to verify the above simulations. In the situations of calibration and work, the same property (conductivity and dielectric constant) material as target electrode should be chosen for capacitive hydrostatic leveling sensors. Otherwise, there is an error of sensors after calibration, and the main factor is conductivity. (authors)
Quasi-hydrostatic Primitive Equations for Ocean Global Circulation Models
Institute of Scientific and Technical Information of China (English)
Carine LUCAS; Madalina PETCU; Antoine ROUSSEAU
2010-01-01
Global existence of weak and strong solutions to the quasi-hydrostatic primitive equations is studied in this paper.This model,that derives from the full non-hydrostatic model for geophysical fluid dynamics in the zero-limit of the aspect ratio,is more realistic than the classical hydrostatic model,since the traditional approximation that consists in neglecting a part of the Coriolis force is relaxed.After justifying the derivation of the model,the authors provide a rigorous proof of global existence of weak solutions,and well-posedness for strong solutions in dimension three.
WORK PRINCIPLE AND CHARACTERISTIC ANALYSES OF HYDROSTATIC BEARING
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Aiming at the new characteristic of water hydraulic system, a kind of hydrostatic bearing with a concentric gap damper is introduced. The lubricative film thickness of the hydrostatic bearing possesses inflexibility and the loading capacity is just determined by the geometrical dimension of the piston-slipper subassembly and has no relation with system pressure, viscosity and temperature of water and speed of rotor. Theoretical analyses and the verification of scheme done at the test rig show that the hydrostatic bearing with a concentric gap damper is especially fit for water hydraulic components.
Compressive formability of 7075 aluminum alloy rings under hydrostatic pressure
Institute of Scientific and Technical Information of China (English)
LIU Gang; WANG Li-liang; YUAN Shi-jian; WANG Zhong-ren
2006-01-01
In order to investigate the influence of hydrostatic pressure on compression limit of the ring, numerical simulation and experimental research were carried out. The effect of hydrostatic pressure on the deformation of aluminum alloy 7075 ring was obtained by numerical simulation. The die set for compressing ring under high hydrostatic pressure was designed and manufactured. Experimental results show that the compression limit increases linearly as the hydrostatic pressure increases in a certain range. At 100 MPa the maximum compressive strain is increased by 32.42%. At strain limit, the cracks initiate from the corner of the outer wall to the middle of the inner wall along the direction of the maximum shear stress.
Nonlinear Analyses of the Dynamic Properties of Hydrostatic Bearing Systems
Institute of Scientific and Technical Information of China (English)
LIU Wei(刘伟); WU Xiujiang(吴秀江); V.A. Prokopenko
2003-01-01
Nonlinear analyses of hydrostatic bearing systems are necessary to adequately model the fluid-solid interaction. The dynamic properties of linear and nonlinear analytical models of hydrostatic bearings are compared in this paper. The analyses were based on the determination of the aperiodic border of transient processes with external step loads. The results show that the dynamic properties can be most effectively improved by increasing the hydrostatic bearing crosspiece width and additional pocket volume in a bearing can extend the load range for which the transient process is aperiodic, but an additional restrictor and capacitor (RC) chain must be introduced for increasing damping. The nonlinear analyses can also be used to predict typical design parameters for a hydrostatic bearing.
SPR Hydrostatic Column Model Verification and Validation.
Energy Technology Data Exchange (ETDEWEB)
Bettin, Giorgia [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lord, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rudeen, David Keith [Gram, Inc. Albuquerque, NM (United States)
2015-10-01
A Hydrostatic Column Model (HCM) was developed to help differentiate between normal "tight" well behavior and small-leak behavior under nitrogen for testing the pressure integrity of crude oil storage wells at the U.S. Strategic Petroleum Reserve. This effort was motivated by steady, yet distinct, pressure behavior of a series of Big Hill caverns that have been placed under nitrogen for extended period of time. This report describes the HCM model, its functional requirements, the model structure and the verification and validation process. Different modes of operation are also described, which illustrate how the software can be used to model extended nitrogen monitoring and Mechanical Integrity Tests by predicting wellhead pressures along with nitrogen interface movements. Model verification has shown that the program runs correctly and it is implemented as intended. The cavern BH101 long term nitrogen test was used to validate the model which showed very good agreement with measured data. This supports the claim that the model is, in fact, capturing the relevant physical phenomena and can be used to make accurate predictions of both wellhead pressure and interface movements.
Model flames in a hydrostatic atmosphere
Caceres Calleja, Alvaro
A model flame system based on the advection-diffusion-reaction method is defined and used to numerically study the problem of a flame propagating up an initially hydrostatic atmosphere, in 2-D. We identify and characterize the flame's steady states over a range of parameters, in the case where the gravitational scale height is much greater than the size of the flame, which itself is much greater than the flame's laminar width. We observe both laminar and turbulent steady flames and verify that, for strong enough gravity G, the turbulent flame speed is independent of the laminar flame speed and scales like the square root of GL, where L is the size of our domain. As this scaling law is commonly used to implement flame subgrid models, one of the aims of this thesis is to understand its robustness. We describe the flame geometry and discuss its relationship with the flame speed. The flow statistics inside turbulent flames are measured and found to be gaussian and isotropic, corresponding to strong mixing.
Control of hydrostatic transmission wind turbine
Rajabhandharaks, Danop
In this study, we proposed a control strategy for a wind turbine that employed a hydrostatic transmission system for transmitting power from the wind turbine rotor via a hydraulic transmission line to a ground level generator. Wind turbine power curve tracking was achieved by controlling the hydraulic pump displacement and, at the other end of the hydraulic line, the hydraulic motor displacement was controlled so that the overall transmission loss was minimized. Steady state response, dynamic response, and system stability were assessed. The maximum transmission efficiency obtained ranged from 79% to 84% at steady state when the proposed control strategy was implemented. The leakage and friction losses of the hydraulic components were the main factors that compromised the efficiency. The simulation results showed that the system was stable and had fast and well-damped transient response. Double wind turbine system sharing hydraulic pipes, a hydraulic motor, and a generator were also studied. The hydraulic pipe diameter used in the double-turbine system increased by 27% compared to the single-turbine system in order to make the transmission coefficient comparable between both systems. The simulation results suggested that the leakage losses were so significant that the efficiency of the system was worsened compared with the single-turbine system. Future studies of other behavioral aspects and practical issues such as fluid dynamics, structure strength, materials, and costs are needed.
Testing Strict Hydrostatic Equilibrium in Abell 1689
Molnar, S M; Hearn, N; Broadhurst, T; Bryan, G; Shang, C
2010-01-01
Recent mass estimates of the well-studied massive galaxy cluster Abell 1689 based on X-ray observations and gravitational lensing, assuming spherical symmetry, still give discrepant results. Contamination by a cool component, substructure and triaxial gas distribution have been proposed to resolve this discrepancy. However, none of these solutions is fully consistent with all observations and predictions of cold dark matter models. A common assumption in all proposed solutions is strict hydrostatic equilibrium, i.e., the gas pressure is provided entirely by thermal pressure, P_he = P_th. We derive P_th and P_he from X-ray and gravitational lensing observations of A1689 in order to test the validity of this assumption. Assuming spherical symmetry, we find that P_th/P_he ~0.6 within the core region of this cluster. We analyze a sample of massive clusters of galaxies drawn from high resolution cosmological simulations, and find, in accord with previous studies, that there is a significant contribution from non-t...
Hydrodynamic Analysis to Process of Hydrostatic Extrusion for Tungsten Alloy
Institute of Scientific and Technical Information of China (English)
Fuchi WANG; Zhaohui ZHANG; Shukui LI
2001-01-01
The hydrodynamic analysis to the process of the hydrostatic extrusion for tungsten alloy is carried through the hydrodynamic lubrication theory and Reynolds equation in this paper. The critical velocity equation when the hydrodynamic lubrication conditions appear between the surfaces of the work- piece and the die is obtained, and the relationship between the critical velocity and the extrusion parameters is discussed, which build the theoretical bases to the application of the hydrostatic extrusion for tungsten alloy.
Stationary surgical smoke evacuation systems.
2001-03-01
Two types of systems are available for evacuating the surgical smoke created by electrosurgery and laser surgery: portable and stationary surgical smoke evacuation systems. While portable systems dominate the market today, stationary systems are an alternative worth considering--even though they are still in their infancy, with fewer than 90 systems installed to date. Stationary systems represent a major commitment on the part of the healthcare facility. Several system components must be installed as part of the physical plant (for instance, within the walls), making the system a permanent fixture in the surgical suite. Installation of these systems is often carried out during building construction or major renovation--although the systems can be cost-effective even if no renovations are planned. For this Evaluation, we tested three stationary systems. All three are adequate to capture surgical smoke and evacuate it from the operating room. These systems are easy to use, are quietter than their portable counterparts, and require minimal user maintenance. They represent an excellent option for most hospitals actively evacuating surgical smoke. In this article, we discuss the factors to consider when selecting from among these systems. We also offer guidance on choosing between stationary systems and portable ones. PMID:11321758
Conformal extensions for stationary spacetimes
Aceña, Andrés E
2011-01-01
The construction of the cylinder at spatial infinity for stationary spacetimes is considered. Using a specific conformal gauge and frame, it is shown that the tensorial fields associated to the conformal Einstein field equations admit expansions in a neighbourhood of the cylinder at spatial infinity which are analytic with respect to some suitable time, radial and angular coordinates. It is then shown that the essentials of the construction are independent of the choice of conformal gauge. As a consequence, one finds that the construction of the cylinder at spatial infinity and the regular finite initial value problem for stationary initial data sets are, in a precise sense, as regular as they could be.
The stationary neutron radiography system
International Nuclear Information System (INIS)
To provide the high intensity neutron beam and support systems necessary for radiography, the Stationary Neutron Radiography System was constructed at McClellan Air Force Base. The Stationary Neutron Radiography System utilizes a one megawatt TRIGA reactor contained in an Aluminium tank surrounded by eight foot thick concrete walls. There are four neutron beam tubes at inclined angles from the reactor core to separate radiography bays. In three of the bays, robotic systems manipulate aircraft components in the neutron beam, while real-time imaging systems provide images concurrent with the irradiation. Film radiography of smaller components is performed in the remaining bay
Hydrostatic Microextrusion of Steel and Copper
International Nuclear Information System (INIS)
The paper presents an experimental investigation based on hydrostatic micro extrusion of billets in low carbon steel and commercially pure copper, and the relevant results. The starting billets have a diameter of 0.3 mm and are 5 mm long; a high pressure generator consisting of a manually operated piston screw pump is used to pressurize the fluid up to 4200 bar, the screw pump is connected through a 3-way distribution block to the extrusion die and to a strain gauge high pressure sensor. The sensor has a full scale of 5000 bar and the extrusion pressure is acquired at a sampling rate of 2 kHz by means of an acquisition program written in the LabVIEW environment. Tests have been conducted at room temperature and a lubricant for wire drawing (Chemetall Gardolube DO 338) acts both as the pressurizing fluid and lubricant too. In addition, billets were graphite coated. Different fluid pressures and process durations have been adopted, resulting in different extrusion lengths. The required extrusion pressure is much higher than in non-micro forming operations (this effect is more evident for steel). On the cross section of the extruded parts, hardness and grain size distribution have been measured, the former through Vickers micro hardness (10 g load) tests. In the case of the extrusion of copper, the material behaves as in microdrawing process. In the case of the extrusion of steel, the hardness increases from the core to the surface as in the drawing process, but with lower values. The analysis evidenced the presence of the external layer, but its thickness is about 1/3 of the external layer in the drawn wire and the grains appear smaller than in the layer of the drawn wire. The extruding force required along the extruding direction is higher (22-24 N) than the drawing force along the same direction (12 N): being the material, the reduction ratio, the die sliding length the same in both cases, the higher extrusion force should be caused by a higher tangential friction
Learning in Non-Stationary Environments Methods and Applications
Lughofer, Edwin
2012-01-01
Recent decades have seen rapid advances in automatization processes, supported by modern machines and computers. The result is significant increases in system complexity and state changes, information sources, the need for faster data handling and the integration of environmental influences. Intelligent systems, equipped with a taxonomy of data-driven system identification and machine learning algorithms, can handle these problems partially. Conventional learning algorithms in a batch off-line setting fail whenever dynamic changes of the process appear due to non-stationary environments and external influences. Learning in Non-Stationary Environments: Methods and Applications offers a wide-ranging, comprehensive review of recent developments and important methodologies in the field. The coverage focuses on dynamic learning in unsupervised problems, dynamic learning in supervised classification and dynamic learning in supervised regression problems. A later section is dedicated to applications in which dyna...
Hydrostatic Stress Effect on the Yield Behavior of Inconel 100
Allen, Phillip A.; Wilson, Christopher D.
2003-01-01
Classical metal plasticity theory assumes that hydrostatic stress has negligible effect on the yield and postyield behavior of metals. Recent reexaminations of classical theory have revealed a significant effect of hydrostatic stress on the yield behavior of various geometries. Fatigue tests and nonlinear finite element analyses (FEA) of Inconel 100 (IN100) equal-arm bend specimens and new monotonic tests and nonlinear finite element analyses of IN100 smooth tension, smooth compression, and double-edge notch tension (DENT) test specimens have revealed the effect of internal hydrostatic tensile stresses on yielding. Nonlinear FEA using the von Mises (yielding is independent of hydrostatic stress) and the Drucker-Prager (yielding is linearly dependent on hydrostatic stress) yield functions were performed. A new FEA constitutive model was developed that incorporates a pressure-dependent yield function with combined multilinear kinematic and multilinear isotropic hardening using the ABAQUS user subroutine (UMAT) utility. In all monotonic tensile test cases, the von Mises constitutive model, overestimated the load for a given displacement or strain. Considering the failure displacements or strains for the DENT specimen, the Drucker-Prager FEM s predicted loads that were approximately 3% lower than the von Mises values. For the failure loads, the Drucker Prager FEM s predicted strains that were up to 35% greater than the von Mises values. Both the Drucker-Prager model and the von Mises model performed equally-well in simulating the equal-arm bend fatigue test.
Well balanced finite volume methods for nearly hydrostatic flows
International Nuclear Information System (INIS)
In numerical approximations of nearly hydrostatic flows, a proper representation of the dominant hydrostatic balance is of crucial importance: unbalanced truncation errors can induce unacceptable spurious motions, e.g., in dynamical cores of models for numerical weather prediction (NWP) in particular near steep topography. In this paper we develop a new strategy for the construction of discretizations that are 'well-balanced' with respect to dominant hydrostatics. The classical idea of formulating the momentum balance in terms of deviations of pressure from a balanced background distribution is realized here through local, time dependent hydrostatic reconstructions. Balanced discretizations of the pressure gradient and of the gravitation source term are achieved through a 'discrete Archimedes' buoyancy principle'. This strategy is applied to extend an explicit standard finite volume Godunov-type scheme for compressible flows with minimal modifications. The resulting method has the following features: (i) It inherits its conservation properties from the underlying base scheme. (ii) It is exactly balanced, even on curvilinear grids, for a large class of near-hydrostatic flows. (iii) It solves the full compressible flow equations without reference to a background state that is defined for an entire vertical column of air. (iv) It is robust with respect to details of the implementation, such as the choice of slope limiting functions, or the particularities of boundary condition discretizations
Orientation of hydraulic fractures in SALT under hydrostatic and non-hydrostatic stresses
International Nuclear Information System (INIS)
A series of laboratory experiments were performed to determine the influence of deviatoric in situ stress on the form and orientation of hydraulic fractures in salt. The principal hydraulic fracturing tests were run on prismatic blocks confined in a polyaxial loading frame using flatjacks. The vertical stress and the minimum horizontal stress were 10.3 MPa for all tests. The maximum horizontal stress was varied form 10.3 MPa to 15.5 MPa to provide a range of horizontal stress ratios from 1.0 (hydrostatic) to 1.5. The fracturing oil contained a fluorescent dye that marked the fracture traces for mapping after the samples were split. At high stress ratios (1.5) the hydraulic fractures formed as two distinct traces emanating from opposite sides of the borehole in the maximum horizontal stress direction. At progressively lower stress ratios the orientations of the fractures varied about the maximum stress direction, and the fracture traces tended to branch. At stress ratios below between 1.10 and 1.13 the fracture no longer appeared to have an orientation controlled by the in situ stress directions. The results indicate that the form of the hydraulic fracture reflects whether or not the stresses are nearly hydrostatic. Fracture form can be determined by mapping dyed hydraulic fractures underground. The fractures should be made in portions of an underground facility that are to be excavated, and the fractures should be mapped as the excavation proceeds through the area of fracturing. 2 refs., 13 figs., 2 tabs
Condensational theory of stationary tornadoes
Makarieva, Anastassia M; Nefiodov, Andrei V; 10.1016/j.physleta.2011.04.023
2012-01-01
Using the Bernoulli integral for air streamline with condensing water vapor a stationary axisymmetric tornado circulation is described. The obtained profiles of vertical, radial and tangential velocities are in agreement with observations for the Mulhall tornado, world's largest on record and longest-lived among the three tornadoes for which 3D velocity data are available. Maximum possible vortex velocities are estimated.
Hydrostatic testing of power generating plant for atomic electric stations
International Nuclear Information System (INIS)
Descriptions are given of layouts for the hydrostatic testing of products; these vary according to the shell material and the technical specifications of the different test fluids. Recommendations are made for the organization of central installations for supplying several test sections with the necessary fluid, with these sections being suitably located close to such a centralized installation. Special features of the hydrostatic testing of large-volume components at test pressures of 20 MPa and over are discussed, as well as the problems of guaranteeing the safety of workers and equipment
Directory of Open Access Journals (Sweden)
Zhiwei WANG
2016-06-01
Full Text Available At present, the research on static and dynamic characteristics of hydrostatic supports depend on the form and structure of the restrictor, which are mainly focused on the influences of recess shape, bearing structure, bearing surface roughness, lubricant and elastic deformations of the bearing. There are few studies on the thermal effect of hydrostatic supports and static and dynamic characteristics of hydrostatic guideways. The research on motion errors of hydrostatic supports is primarily based on the static equilibrium of the moving part. The effects of the motion speed of the moving part and structural deformation on the motion errors are not considered. Finally, the research prospects from the standardization, modularization and industrialization of hydrostatic supports, thermal effect of hydrostatic bearing, the static and dynamic characteristics of hydrostatic guideways and motion errors of hydrostatic supports under operating conditions are concluded.
Non-Stationary Kriging For Design Optimization
Toal, D. J.J.; Keane, A. J.
2011-01-01
Abstract Traditional surrogate modelling techniques, such as kriging, have been employed quite effectively within design optimizations. However, such models can fail to accurately reproduce non-stationary responses. The following paper explores the application of non-stationary kriging to design optimization and attempts to determine its applicability with regard to the optimization of both stationary and non-stationary objective functions. A series of analytical test problems and ...
Stationary plasma accelerator - ATON engine
International Nuclear Information System (INIS)
The principles of a stationary plasma accelerator (engine) with closed electron drift are described. The accelerator has record integral characteristics. A method for analysis of operating process features in the integral characteristics is proposed. Results are presented of local measurements of the plasma parameters in the accelerator channel and in the leaving plasma jet Main attention is paid to determination of the part of twice ionized ions in the plasma flow
Are stationary hyperinflation paths learnable?
Adam, Klaus; W., George; Honkapohja, Seppo
2003-01-01
Earlier studies of the seigniorage inflation model have found that the high-inflation steady state is not stable under adaptive learning. We reconsider this issue and analyze the full set of solutions for the linearized model. Our main focus is on stationary hyperinflationary paths near the high-inflation steady state. The hyperinflationary paths are stable under learning if agents can utilize contemporaneous data. However, in an economy populated by a mixture of agents, some of whom only hav...
Comparison of hydrostatic and hydrodynamic pressure to inactivate foodborne viruses
The effect of high hydrostatic pressure (HPP) and hydrodynamic pressure (HDP), in combination with chemical treatments, was evaluated for inactivation of foodborne viruses and non-pathogenic surrogates in a pork sausage product. Sausages were immersed in water, 100 ppm EDTA, or 2 percent lactoferrin...
Brittle thermoelectric semiconductors extrusion under high hydrostatic pressure
International Nuclear Information System (INIS)
Origins of strength increase of brittle materials like thermoelectric (TE) semiconductors during plastic deformation under high external pressure are analyzed. TE material stressed state in the process of extrusion is reviewed. Plastic deformation of monocrystalline TE material billet produced by extrusion under sufficiently high external hydrostatic pressure is more uniform than under ordinary ambient pressure and can lead to crack free extruded TE material structure, crystallographic symmetry of which coincides with original billet one. Experimental device realized the scheme of extrusion under high hydrostatic pressure is described. Here extrusion are carrying out in compressed liquid medium. The developed device ensures the value of hydrostatic pressure up to 2 GPa and extrusion temperature interval 300--600 K. Properties of extruded Bi-Sb and Bi-Sb-Te single crystals are also reviewed. Possible application of presented method of extrusion under high hydrostatic pressure to form TE branches with highly accurate cross section for miniature TE coolers or generators is discussed. copyright 1995 American Institute of Physics
N2 vs H20 as purge/hydrostatic head
International Nuclear Information System (INIS)
This document provides the information to explain to the customer the ETP for the N2 vs H20 as Purge/Hydrostatic Head. This ETP follows the format described in Issurance of New Characterization Equipment Engineering Desk Instructions, 75200-95-013
Numerical construction of magneto-hydrostatic atmospheres in three dimensions
Gilchrist, Stuart; Braun, Douglas; Barnes, Graham
2016-05-01
There is a general interest in constructing magneto-hydrostatic models of the solar atmosphere. These models describe large-scale, long-lived magnetic structures like sunspots, prominences, coronal loops, and the corona itself on global scales. The nonlinearity of the magneto-hydrostatic equations prohibits direct analytic solution except when idealized approximations like self-similarity are made. Numerical approaches, too, are limited in scope, and primarily focus on the two-dimensional problem --- the general three-dimensional magneto-hydrostatic problem is not treated. In this presentation we present a new numerical scheme for solving the magneto-hydrostatic equations in three dimensions. We are presently using this method to construct sunspot models for helioseismic MHD wave-propagation simulations with the goal of comparing the simulations to local-helioseismic measurements. We will present the details of the method and its application to test cases.This work is supported by NASA Heliophysics Division through grant NNX14AD42G and by the NSF Solar-Terrestrial program through grant AGS-1127327.
Nonmonotone Saturation Profiles for Hydrostatic Equilibrium in Homogeneous Porous Media
Hilfer, R.; Doster, F.; Zegeling, P.A.
2012-01-01
Nonmonotonic saturation profiles (saturation overshoot) occur as travelling waves in gravity driven fingering. They seem important for preferential flow mechanisms and have found much attention recently. Here, we predict them even for hydrostatic equilibrium when all velocities vanish. We suggest th
Numerical and experimental study of hydrostatic displacement machine
DEFF Research Database (Denmark)
Sørensen, Rasmus Mørk; Hansen, Michael; Mouritsen, Ole Ø.
2012-01-01
This paper presents a simulation tool to determine the structural deflections and corresponding leakage flow in a hydrostatic displacement motor. The simulation tool is applied to a new motor principle that is categorized as an extreme low-speed high-torque motor with dimensions that calls for...
46 CFR 56.97-30 - Hydrostatic tests (modifies 137.4).
2010-10-01
... system is filling. (b) Test medium and test temperature. (1) Water will be used for a hydrostatic leak...) Examination for leakage after application of pressure. Following the application of the hydrostatic test...-transition sections. (e) Minimum required hydrostatic test pressure. Except as otherwise permitted in §...
High efficiency stationary hydrogen storage
Energy Technology Data Exchange (ETDEWEB)
Hynek, S.; Fuller, W.; Truslow, S. [Arthur D. Little, Inc., Cambridge, MA (United States)
1995-09-01
Stationary storage of hydrogen permits one to make hydrogen now and use it later. With stationary hydrogen storage, one can use excess electrical generation capacity to power an electrolyzer, and store the resultant hydrogen for later use or transshipment. One can also use stationary hydrogen as a buffer at fueling stations to accommodate non-steady fueling demand, thus permitting the hydrogen supply system (e.g., methane reformer or electrolyzer) to be sized to meet the average, rather than the peak, demand. We at ADL designed, built, and tested a stationary hydrogen storage device that thermally couples a high-temperature metal hydride to a phase change material (PCM). The PCM captures and stores the heat of the hydriding reaction as its own heat of fusion (that is, it melts), and subsequently returns that heat of fusion (by freezing) to facilitate the dehydriding reaction. A key component of this stationary hydrogen storage device is the metal hydride itself. We used nickel-coated magnesium powder (NCMP) - magnesium particles coated with a thin layer of nickel by means of chemical vapor deposition (CVD). Magnesium hydride can store a higher weight fraction of hydrogen than any other practical metal hydride, and it is less expensive than any other metal hydride. We designed and constructed an experimental NCM/PCM reactor out of 310 stainless steel in the form of a shell-and-tube heat exchanger, with the tube side packed with NCMP and the shell side filled with a eutectic mixture of NaCL, KCl, and MgCl{sub 2}. Our experimental results indicate that with proper attention to limiting thermal losses, our overall efficiency will exceed 90% (DOE goal: >75%) and our overall system cost will be only 33% (DOE goal: <50%) of the value of the delivered hydrogen. It appears that NCMP can be used to purify hydrogen streams and store hydrogen at the same time. These prospects make the NCMP/PCM reactor an attractive component in a reformer-based hydrogen fueling station.
Indian Academy of Sciences (India)
P K Karmakar
2011-06-01
The pulsational mode of gravitational collapse (PMGC) in a hydrostatically bounded dust molecular cloud is responsible for the evolution of tremendous amount of energy during star formation. The source of free energy for this gravito-electrostatic instability lies in the associated self-gravity of the dispersed phase of relatively huge dust grains of solid matter over the gaseous phase of background plasma. The nonlinear stability of the same PMGC in an inﬁnite dusty plasma model (plane geometry approximation for large wavelength ﬂuctuation in the absence of curvature effects) is studied in a hydrostatic kind of homogeneous equilibrium conﬁguration. By the standard reductive perturbation technique, a Korteweg–de Vries (KdV) equation for investigating the nonlinear evolution of the lowest order perturbed self-gravitational potential is developed in a time-stationary (steady-state) form, which is studied analytically as well as numerically. Different nonlinear structures (soliton-like and soliton chain-like) are found to exist in different situations. Astrophysical situations, relevant to it, are brieﬂy discussed.
Stationary bubbles: information loss paradox?
Domènech, Guillem
2016-01-01
The main purpose of this work is to build classically stationary bubbles, within the thin-shell formalism, which are unstable under quantum effects; they either collapse into a black hole or expand. Thus, the final state can be thought of a superposition of geometries. We point out that, from a quantum mechanical point of view, there is no issue with a loss of information in such configuration. A classical observer sees a definite geometry and, hence, finds an effective loss of information. Although it does not cover all possible cases, we emphasise the role of semi-classical gravitational effects, mediated by instatons, in alleviating/solving the information loss paradox.
Influence of Floating Monitoring Platform Structure on the Hydrostatic Characteristics
Directory of Open Access Journals (Sweden)
Su Feng
2015-01-01
Full Text Available According to the environment and work styles, the underwater monitoring devices can be divided into three type, fixed monitoring device, the floating monitoring device and mobile monitoring device. Floating monitoring platform is a new type of monitoring device of the floating monitoring device, which is mainly used for underwater video monitoring of pool. as the floating platform monitoring in water motion and hydrostatic characteristics are closely related, the influent of counterweight, weight distance and floating body diameter of the structure parameters on its hydrostatic characteristics and the natural periods for roll, pitch and heave should be considered, In this work, the floating body diameter influent most, the counterweight followed, and the structure parameters have different influence on the natural periods for roll, pitch and heave , it need to be analyzed according to the concrete structure parameters.
Hydrostatic Pressure Sensing with High Birefringence Photonic Crystal Fibers
Fávero, Fernando C.; Quintero, Sully M. M.; Martelli, Cicero; Braga, Arthur M.B.; Silva, Vinícius V.; Carvalho, Isabel C. S.; Llerena, Roberth W. A.; Valente, Luiz C. G.
2010-01-01
The effect of hydrostatic pressure on the waveguiding properties of high birefringence photonic crystal fibers (HiBi PCF) is evaluated both numerically and experimentally. A fiber design presenting form birefringence induced by two enlarged holes in the innermost ring defining the fiber core is investigated. Numerical results show that modal sensitivity to the applied pressure depends on the diameters of the holes, and can be tailored by independently varying the sizes of the large or small holes. Numerical and experimental results are compared showing excellent agreement. A hydrostatic pressure sensor is proposed and demonstrated using an in-fiber modal interferometer where the two orthogonally polarized modes of a HiBi PCF generate fringes over the optical spectrum of a broad band source. From the analysis of experimental results, it is concluded that, in principle, an operating limit of 92 MPa in pressure could be achieved with 0.0003% of full scale resolution. PMID:22163435
Application of hydrostatic extrusion to fabrication of zircaloy tubing
International Nuclear Information System (INIS)
Two approaches are presented to the fabrication of BWR Zircaloy cladding tubes: (7) replacing the final pass of the pilgering process with cold hydrostatic extrusion, and (2) application of hot hydrostatic extrusion to the manufacture of tube shells which are then processed by the conventional pilgering process. With the first approach, an extrusion ratio (ER) of 5 could be obtained, but it should be limited to a maximum of 3 to prevent the occurence of galling. The properties of the obtained tubes were nearly identical to those of the current BWR cladding tubes. Application of the second technique resulted in an increase of ER to three times that of the conventional direct extrusion. The tubing processed at higher ER showed higher strength and lower ductility in the tension tests but exhibited higher ductility in the burst tests. 5 refs
The influence of hydrostatic pressure on tissue engineered bone development.
Neßler, K H L; Henstock, J R; El Haj, A J; Waters, S L; Whiteley, J P; Osborne, J M
2016-04-01
The hydrostatic pressure stimulation of an appropriately cell-seeded porous scaffold within a bioreactor is a promising method for engineering bone tissue external to the body. We propose a mathematical model, and employ a suite of candidate constitutive laws, to qualitatively describe the effect of applied hydrostatic pressure on the quantity of minerals deposited in such an experimental setup. By comparing data from numerical simulations with experimental observations under a number of stimulation protocols, we suggest that the response of bone cells to an applied pressure requires consideration of two components; (i) a component describing the cell memory of the applied stimulation, and (ii) a recovery component, capturing the time cells require to recover from high rates of mineralisation. PMID:26796221
High hydrostatic pressure tests of the unsaturated polyester products
International Nuclear Information System (INIS)
For the purpose of evaluating the adaptability of the unsaturated polyester products to sea disposal, the leaching of radionuclides and integrity testes were carried out under high hydrostatic pressure. These testes were carried out for about a month under the conditions simulating hydrostatic pressure (500 ± 5 kg/cm2), temperature (2 ± 0.5 deg C) and flow rate (1.1 cm/sec) on the sea bed of 5,000 m depth level. The test results indicated that these products kept the integrity under the above-mentioned conditions and that they had a low leachability. Therefore, it is concluded that these products were adaptable enough to sea disposal without losing their high volume reduction property compared with cement solidified wastes. (author)
LoCuSS: Testing hydrostatic equilibrium in galaxy clusters
Smith, G. P.; Mazzotta, P.; Okabe, N.; Ziparo, F.; Mulroy, S. L.; Babul, A.; Finoguenov, A.; McCarthy, I. G.; Lieu, M.; Bahé, Y. M.; Bourdin, H.; Evrard, A. E.; Futamase, T.; Haines, C. P.; Jauzac, M.; Marrone, D. P.; Martino, R.; May, P. E.; Taylor, J. E.; Umetsu, K.
2016-02-01
We test the assumption of hydrostatic equilibrium in an X-ray luminosity selected sample of 50 galaxy clusters at 0.15 sub-4 per cent, and our hydrostatic measurements of the same achieve excellent agreement between XMM-Newton and Chandra. The mean ratio of X-ray to lensing mass for these 50 clusters is β_X= 0.95± 0.05, and for the 44 clusters also detected by Planck, the mean ratio of Planck mass estimate to LoCuSS lensing mass is β_P= 0.95± 0.04. Based on a careful like-for-like analysis, we find that LoCuSS, the Canadian Cluster Comparison Project, and Weighing the Giants agree on β_P ≃ 0.9-0.95 at 0.15 Planck cosmology results from the cosmic microwave background and galaxy cluster counts.
Achieving Textbook Multigrid Efficiency for Hydrostatic Ice Sheet Flow
Brown, Jed
2013-03-12
The hydrostatic equations for ice sheet flow offer improved fidelity compared with the shallow ice approximation and shallow stream approximation popular in today\\'s ice sheet models. Nevertheless, they present a serious bottleneck because they require the solution of a three-dimensional (3D) nonlinear system, as opposed to the two-dimensional system present in the shallow stream approximation. This 3D system is posed on high-aspect domains with strong anisotropy and variation in coefficients, making it expensive to solve with current methods. This paper presents a Newton--Krylov multigrid solver for the hydrostatic equations that demonstrates textbook multigrid efficiency (an order of magnitude reduction in residual per iteration and solution of the fine-level system at a small multiple of the cost of a residual evaluation). Scalability on Blue Gene/P is demonstrated, and the method is compared to various algebraic methods that are in use or have been proposed as viable approaches.
Imperfection effects on the buckling of hydrostatically loaded cylinders
DEFF Research Database (Denmark)
Pinna, Rodney; Madsen, Søren
2015-01-01
in design has also increased. Practical guidance on how to do this is fairly limited, in particular for geometries or load conditions other than the standard cases. The effect of imperfections on the collapse load of cylinders under axial load has been studied extensively, as such cylinders show the......The presence of geometric and other imperfections in cylinders has been known to result in collapse loads well below those predicted from eigenvalue analysis for a long time. As the designer's ability to routinely employ non-linear FEA has increased, the importance of modelling such imperfections...... largest imperfection sensitivity. Work on cylinders with other loading conditions, such as hydrostatic loading, is more limited. Similarly, there is limited work on cylinders with boundary conditions other than simply-supported ends. This paper looks at the case of cylinders under hydrostatic load, which...
Synthesis of an electro hydrostatic actuator from bicausal bond graphs
Gandanegara, Grace; Roboam, Xavier; Maré, Jean-Charles; Sareni, Bruno
2007-01-01
In this paper, the structure of an Electro Hydrostatic Actuator (EHA) devoted to flight control surfaces is firstly described by its Causal Bond Graph (CBG). Then, verifying the inversion conditions, the Bicausal Bond Graph (BBG) can be obtained to synthesize the system inputs (electrical constraints) from the outputs (aerodynamic torque and position of the flight control surface) given by data stored during an actual "flight mission". The particular issues of filtering and of synthesis by mo...
Equal-order finite elements of hydrostatic flow problems
Kimmritz, Madlen
2013-01-01
Subject of this thesis is the issue of equal-order finite element discretization of hydrostatic flow problems. These flow problems typically arise in geophysical fluid dynamics on large scales and in flat domains. This small aspect ratio between the depth and the horizontal extents of the considered domain allows to efficiently reduce the complexity of the incompressible three dimensional Navier-Stokes equations, which form the basis of geophysical flows. In the resulting set of equations, th...
Hydrostatic bearings for a turbine fluid flow metering device
Fincke, J.R.
1980-05-02
A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion.
Cold hydrostatic extrusion of powder metallurgy processed superconducting materials
International Nuclear Information System (INIS)
Hydrostatically extruded multifilamentary composites of Cu-Nb, Cu-Nb with a central tin core and Nb-Al were directly drawn to fine wires without intermediate annealing. Uniform deformation was observed throughout the process. Cu-Nb composite wires were Sn plated for external diffusion. Overall critical current densities of better than 104 A/cm2 at 16 T were achieved for Nb3Sn-Cu composite wires with nominal areal reductions of 2000
On the quasi-hydrostatic quasi-geostrophic model
Lucas, Carine; Mcwilliams, James C.; Rousseau, Antoine
2015-01-01
This paper introduces a rigorous derivation of the quasi-hydrostatic quasi-geostrophic (QHQG) equations of large scale ocean as the Rossby number goes to zero. We follow classical techniques for the derivation of the quasi-geostrophic (QG) equations (as in [BB94]), but the primitive equations that we consider account for the nontraditional rotating terms, as in [LPR10]. We end up with a slightly different QG model with a tilted vertical direction, which has been illustrated in previous works ...
Can Hydrostatic Cores Form Within Isothermal Molecular Clouds?
Vazquez-Semadeni, Enrique; Shadmehri, Mohsen; Ballesteros-Paredes, Javier
2002-01-01
Under the assumptions that molecular clouds are nearly spatially and temporally isothermal and that the density peaks (``cores'') within them are formed by turbulent fluctuations, we argue that cores cannot reach a hydrostatic (or magneto-static) state as a consequence of their formation process. In the non-magnetic case, stabilization requires a Bonnor-Ebert truncation at a finite radius, which is not feasible for a single-temperature flow, unless it amounts to a shock, which is clearly a dy...
Mechanical response of collagen molecule under hydrostatic compression
Energy Technology Data Exchange (ETDEWEB)
Saini, Karanvir, E-mail: karans@iitrpr.ac.in; Kumar, Navin
2015-04-01
Proteins like collagen are the basic building blocks of various body tissues (soft and hard). Collagen molecules find their presence in the skeletal system of the body where they bear mechanical loads from different directions, either individually or along with hydroxy-apatite crystals. Therefore, it is very important to understand the mechanical behavior of the collagen molecule which is subjected to multi-axial state of loading. The estimation of strains of collagen molecule along different directions resulting from the changes in hydrostatic pressure magnitude, can provide us new insights into its mechanical behavior. In the present work, full atomistic simulations have been used to study global (volumetric) as well as local (along different directions) mechanical properties of the hydrated collagen molecule which is subjected to different hydrostatic pressure magnitudes. To estimate the local mechanical properties, the strains of collagen molecule along its longitudinal and transverse directions have been acquired at different hydrostatic pressure magnitudes. In spite of non-homogeneous distribution of atoms within the collagen molecule, the calculated values of local mechanical properties have been found to carry the same order of magnitude along the longitudinal and transverse directions. It has been demonstrated that the values of global mechanical properties like compressibility, bulk modulus, etc. as well as local mechanical properties like linear compressibility, linear elastic modulus, etc. are functions of magnitudes of applied hydrostatic pressures. The mechanical characteristics of collagen molecule based on the atomistic model have also been compared with that of the continuum model in the present work. The comparison showed up orthotropic material behavior for the collagen molecule. The information on collagen molecule provided in the present study can be very helpful in designing the future bio-materials.
Response of Pathogenic Vibrio Species to High Hydrostatic Pressure
Berlin, Daniel L.; Herson, Diane S.; Hicks, Doris T.; Hoover, Dallas G.
1999-01-01
Vibrio parahaemolyticus ATCC 17802, Vibrio vulnificus ATCC 27562, Vibrio cholerae O:1 ATCC 14035, Vibrio cholerae non-O:1 ATCC 14547, Vibrio hollisae ATCC 33564, and Vibrio mimicus ATCC 33653 were treated with 200 to 300 MPa for 5 to 15 min at 25°C. High hydrostatic pressure inactivated all strains of pathogenic Vibrio without triggering a viable but nonculturable (VBNC) state; however, cells already existing in a VBNC state appeared to possess greater pressure resistance.
LoCuSS: Testing hydrostatic equilibrium in galaxy clusters
Smith, G P; Okabe, N; Ziparo, F; Mulroy, S L; Babul, A; Finoguenov, A; McCarthy, I G; Lieu, M; Bahe, Y; Bourdin, H; Evrard, A E; Futamase, T; Haines, C P; Jauzac, M; Marrone, D P; Martino, R; May, P E; Taylor, J E; Umetsu, K
2015-01-01
We test the assumption of hydrostatic equilibrium in an X-ray luminosity selected sample of 50 galaxy clusters at $0.15
Strong Stationary Duality for Diffusion Processes
fill, james Allen; Lyzinski, Vince
2014-01-01
We develop the theory of strong stationary duality for diffusion processes on compact intervals. We analytically derive the generator and boundary behavior of the dual process and recover a central tenet of the classical Markov chain theory in the diffusion setting by linking the separation distance in the primal diffusion to the absorption time in the dual diffusion. We also exhibit our strong stationary dual as the natural limiting process of the strong stationary dual sequence of a well ch...
Stationary fire detection and extinguishing systems in nuclear power plants
International Nuclear Information System (INIS)
A survey is made of stationary automatic fire protection systems in nuclear power stations based on analysis of national and foreign materials. Problems of detecting fires at an early stage are discussed in general terms, and recommendations are made on the use of alarms in various monitored zones, taking into account the fire risk materials contained in them. The main requirement put forward is that several alarms of different kinds should be used in a given zone, careful analysis of the environment being essential to ensure correct positioning of the alarms. For automatic fire extinguishing systems it is also recommended that the special characteristics of the combustible materials be taken into account and that a certain amount of redundancy be installed. Given the nature of nuclear power plant operations and the increased fire risk which would ensue if time were required for decisions, automatic triggering is considered preferable to manual triggering. Since fire warning and equipment control systems must be extremely reliable when a fire breaks out, a decentralized structure of monitoring equipment and redundancy of wiring (communication lines) are regarded as essential features of an effective nuclear power plant fire control system. (author)
Condensational theory of stationary tornadoes
International Nuclear Information System (INIS)
Using the Bernoulli integral for air streamline with condensing water vapor a stationary axisymmetric tornado circulation is described. The obtained profiles of vertical, radial and tangential velocities are in agreement with observations for the Mulhall tornado, world's largest on record and longest-lived among the three tornadoes for which 3D velocity data are available. Maximum possible vortex velocities are estimated. -- Highlights: → Water vapor condensation causes a logarithmic drop of air pressure towards tornado center. → The first ever theoretical description of tornado velocities is obtained. → The maximum vortex velocity grows logarithmically with decreasing tornado eye radius. → Air motion with high velocities can only develop in sufficiently large condensation areas.
Microdynamics in stationary complex networks
Gautreau, Aurelien; Barthelemy, Marc
2008-01-01
Many complex systems, including networks, are not static but can display strong fluctuations at various time scales. Characterizing the dynamics in complex networks is thus of the utmost importance in the understanding of these networks and of the dynamical processes taking place on them. In this article, we study the example of the US airport network in the time period 1990-2000. We show that even if the statistical distributions of most indicators are stationary, an intense activity takes place at the local (`microscopic') level, with many disappearing/appearing connections (links) between airports. We find that connections have a very broad distribution of lifetimes, and we introduce a set of metrics to characterize the links' dynamics. We observe in particular that the links which disappear have essentially the same properties as the ones which appear, and that links which connect airports with very different traffic are very volatile. Motivated by this empirical study, we propose a model of dynamical net...
A new generation of the regional climate model REMO: REMO non-hydrostatic
Sieck, Kevin; Raub, Thomas; Marien, Lennart; Buntemeyer, Lars; Jacob, Daniela
2016-04-01
The regional climate model REMO is well established and has proofed it's value in regional climate simulations for more than a decade. However, due to the hydrostatic formulation REMO is not able to produce useful regional climate information on scales smaller than ~10 km. The demand for higher resolution data especially in the climate service sector is evident. Often climate change information on urban district or even point level is needed. A previous development of a non-hydrostatic dynamical core for REMO utilizing ideas of Miller and Pearce (1974) and Janjic (2001) has been picked up and implemented into the latest hydrostatic REMO version. One of the advantages of the Janjic formulation is that hydrostatic and non-hydrostatic computations are well separated. This offers a straightforward implementation of the non-hydrostatic calculations into an existing hydrostatic model. Other advantages are the easy quantification of the error done by the hydrostatic approximation and the lower computational costs at lower resolutions by switching of the non-hydrostatic part. We will show results from climate simulations on the EURO-CORDEX domain with and without non-hydrostatic option.
Compression of α-cristobalite under different hydrostatic conditions
Cernok, Ana; Marquardt, Katharina; Bykova, Elena; Liermann, Hanns-Peter; Dubrovinsky, Leonid
2015-04-01
The response of α-cristobalite to high-pressure has been a subject of numerous experimental and theoretical studies for more than two decades. The results indicated prolific polymorphism under high pressures, yet no consensus has emerged on what is the sequence of these pressure-induced transformations. In particular, the structure of the high-pressure polymorph that appears above ~10 GPa (hereafter cristobalite X-I), which is believed to be a direct link between the low-pressure (silicon in SiO4 tetrahedra) and the high-pressure (SiO6 octahedra) forms of silica remained elusive. This study examined the response of α-cristobalite when compressed at different levels of hydrostaticity, with the special focus on formation and stability of cristobalite X-I. The structural behavior of cristobalite under pressure was investigated up to ~80 GPa and at ambient temperature. We investigated behavior of single crystals and powders, in either (quasy)-hydrostatic or non-hydrostatic environment. In situ high pressure transformation path and structural behavior was studied by means of Raman spectroscopy and synchrotron X-ray diffraction (XRD). The samples recovered after pressure release were additionally investigated by transmission electron microscopy (TEM). Low- or α-cristobalite responds differently to high pressure depending on the degree of the hydrostaticity. The highest attainable hydrostaticity preserves the initial structure of cristobalite at least up to ~15 GPa. When the crystal experiences even slight stresses during an experiment, transformation sequence leads to cristobalite X-I - a monoclinic polymorph with silicon in octahedral coordination. This polymorph belongs to the family of the high-pressure silica phases that are comprised of distorted close-packed array of oxygen ions in which silicon atoms fully or partially occupy octahedral sites. The reflections collected on a single crystal at ~11 GPa can be indexed by a monoclinic unit cell a=6.658(9) Å, b=4
Stationary Rotating Strings as Relativistic Particle Mechanics
Ogawa, Kouji; Ishihara, Hideki; Kozaki, Hiroshi; Nakano, Hiroyuki; Saito,Shinya
2008-01-01
Stationary rotating strings can be viewed as geodesic motions in appropriate metrics on a two-dimensional space. We obtain all solutions describing stationary rotating strings in flat spacetime as an application. These rotating strings have infinite length with various wiggly shapes. Averaged value of the string energy, the angular momentum and the linear momentum along the string are discussed.
ZF cPower – Hydrostatic-Mechanical Powersplit Transmission for Construction and Forest Machinery
Legner, Jürgen; Rebholz, Wolfgang; Morrison, Robert
2016-01-01
Until recently, hydrostatic-mechanical power split CVT drivelines have not found a place in construction machinery. The majority of these vehicles still use hydrodynamic powershift transmissions, full-hydrostatic transmissions or mechanical direct-shift transmissions. Hydrostatic drive lines are widely used in construction machinery possessing lower engine power. The upper power range is dominated by hydrodynamic powershift transmissions. Decisions made by vehicle manufacturers about which dr...
Sensor of hydrostatic pressure based on gallium antimonide microcrystals
Directory of Open Access Journals (Sweden)
Druzhinin A. A.
2015-08-01
Full Text Available Currently, silicon and germanium, the most common materials in the production of discrete semiconductor devices and integrated circuits, do not always meet all the requirements to the sensing elements of mechanical quantities sensors. Therefore, it is logical to research the properties of other semiconductor materials that could be used as sensing elements in such sensors. A3B5 semiconductor compounds seem promising for such purpose. Effect of hydrostatic pressure up to 5000 bar on the resistance of n-type antimonide gallium whiskers doped by Se or Te was studied. Coefficient of hydrostatic pressure for this crystals was determined, it equals Kh = (16,5—20,0•10–5 bar–1 at 20°N. Temperature dependence of resistance and coefficient Kh for this crystals in the temperature range ±60°N was studied. Design of the developed hydrostatic pressure sensor based on GaSb whiskers and its characteristics are presented. The possibility to decrease the temperature dependence of sensitive element resistance by mounting GaSb whiskers on the substrates fabricated from materials with different temperature coefficient of expansion was examined. It was shown that mounting of GaSb crystals on Cu substrate gives the optimal result, in this case the temperature coefficient decrease to 0,05%•°N–1, that leads to decrease of output temperature dependence. The main advantages of developed pressure sensor are: the simplified design in comparison with pressure sensors with strain gauges mounted on spring elements; the high sensitivity to pressure that is constant in the wide pressure range; the improvement of sensors metrological characteristics owing to hysteresis absence. The possible application fields of developed sensors are measuring of high and extremely high pressure, chemical and oil industries, measuring of pressure in oil bore-holes, investigation of explosive processes.
Hydrostatic pressure dependence of elastic constants for lead fluoride crystal
International Nuclear Information System (INIS)
The variations of the second order elastic constants (SOEC) and longitudinal and shear moduli with hydrostatic pressure for the lead fluoride have been investigated theoretically, for the first time, by means of a three-body force potential (TBP) model. The significance of three-body interactions (TBI) has been clearly demonstrated in these investigations. The present TBP model has reproduced the pressure derivatives of the SOEC of PbF more satisfactorily than the shell model and other model calculations. (author). 24 refs, 3 figs, 2 tabs
A technique to measure rotordynamic coefficients in hydrostatic bearings
Capaldi, Russell J.
1993-11-01
An experimental technique is described for measuring the rotordynamic coefficients of fluid film journal bearings. The bearing tester incorporates a double-spool shaft assembly that permits independent control over the journal spin speed and the frequency of an adjustable-magnitude circular orbit. This configuration yields data that enables determination of the full linear anisotropic rotordynamic coefficient matrices. The dynamic force measurements were made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. Some results are presented for a four-recess, oil-fed hydrostatic journal bearing.
High hydrostatic pressure treatment of porcine oocytes induces parthenogenetic activation
DEFF Research Database (Denmark)
Lin, Lin; Pribenszky, Csaba; Molnár, Miklós; Kragh, Peter M; Du, Yutao; Zhang, Xiuqing; Yang, Huanming; Bolund, Lars; Callesen, Henrik; Macháty, Zoltán; Vajta, Gábor
2010-01-01
An innovative technique called high hydrostatic pressure (HHP) treatment has recently been reported to improve the cryosurvival of gametes and embryos in certain mammalian species, including the mouse, pig, and cattle. In the present study the parthenogenetic activation (PA) of pig oocytes caused...... by HHP treatment was investigated in different holding media with or without Ca(2+). The efficiency of activation was tested at different pressure levels and media including T2 (HEPES-buffered TCM-199 containing 2% cattle serum), and mannitol-PVA fusion medium with (MPVA + Ca(2+)) or without Ca(2...
Hydrostatic pressure sensing with surface-core fibers
Osório, Jonas H.; Franco, Marcos A. R.; Cordeiro, Cristiano M. B.
2015-09-01
In this paper, we report the employment of surface-core fibers for hydrostatic pressure sensing. To our knowledge, this is the first demonstration of the use of these fibers for the referenced purpose. Theoretical simulations of the fiber structure were performed in order to estimate fiber phase and group birefringence values and its pressure sensitivity coefficient. In order to test fiber performance when acting as a pressure sensor, the same was placed in an polarimetric setup and its spectral response was measured. A sensitivity of 4.8 nm/MPa was achieved, showing good resemblance to the expected sensitivity value (4.6 nm/MPa).
Study of graphite strength properties under conditions of hydrostatic pressure
International Nuclear Information System (INIS)
Three graphite grades are studied under compression, tension and hydrostaic pressure. It is shown that an increase in the ultimate strength and higher arrangement of strain curves are observed beginning with a certain value of hydrostatic pressure under compression. Several different types of coatings have been tested under compression and none of them gave a reliable protection against of oil in pores and cracks of a specimen as a result of which the strength values in this case are lower that under atmospheric pressure
Hydrostatic extrusion of Cu-Ag melt spun ribbon
Hill, Mary Ann; Bingert, John F.; Bingert, Sherri A.; Thoma, Dan J.
1998-01-01
The present invention provides a method of producing high-strength and high-conductance copper and silver materials comprising the steps of combining a predetermined ratio of the copper with the silver to produce a composite material, and melt spinning the composite material to produce a ribbon of copper and silver. The ribbon of copper and silver is heated in a hydrogen atmosphere, and thereafter die pressed into a slug. The slug then is placed into a high-purity copper vessel and the vessel is sealed with an electron beam. The vessel and slug then are extruded into wire form using a cold hydrostatic extrusion process.
Descendents on local curves: Stationary theory
Pandharipande, R
2011-01-01
The stable pairs theory of local curves in 3-folds (equivariant with respect to the scaling 2-torus) is studied with stationary descendent insertions. Reduction rules are found to lower descendents when higher than the degree. Factorization then yields a simple proof of rationality in the stationary case and a proof of the functional equation related to inverting q. The method yields an effective determination of stationary descendent integrals. Particular descendent series in the cap geometry play a special role and are calculated exactly using the stable pairs vertex and an analysis of the solution of the quantum differential equation for the Hilbert scheme of points of the plane.
Genetics Home Reference: autosomal dominant congenital stationary night blindness
... stationary night blindness autosomal dominant congenital stationary night blindness Enable Javascript to view the expand/collapse boxes. ... Close All Description Autosomal dominant congenital stationary night blindness is a disorder of the retina , which is ...
Genetics Home Reference: X-linked congenital stationary night blindness
... stationary night blindness X-linked congenital stationary night blindness Enable Javascript to view the expand/collapse boxes. ... Close All Description X-linked congenital stationary night blindness is a disorder of the retina , which is ...
DX centers in III-V semiconductors under hydrostatic pressure
Energy Technology Data Exchange (ETDEWEB)
Wolk, J.A.
1992-11-01
DX centers are deep level defects found in some III-V semiconductors. They have persistent photoconductivity and large difference between thermal and optical ionization energies. Hydrostatic pressure was used to study microstructure of these defects. A new local vibrational mode (LVM) was observed in hydrostatically stressed, Si-doped GaAs. Corresponding infrared absorption peak is distinct from the Si{sub Ga} shallow donor LVM peak, which is the only other LVM peak observed in our samples, and is assigned to the Si DX center. Analysis of the relative intensities of the Si DX LVM and the Si shallow donor LVM peaks, combined with Hall effect and resistivity indicate that the Si DX center is negatively charged. Frequency of this new mode provides clues to the structure of this defect. A pressure induced deep donor level in S-doped InP was also discovered which has the properties of a DX center. Pressure at which the new defect becomes more stable than the shallow donor is 82 kbar. Optical ionization energy and energy dependence of the optical absorption cross section was measured for this new effect. Capture barrier from the conduction band into the DX state were also determined. That DX centers can be formed in InP by pressure suggests that DX states should be common in n-type III-V semiconductors. A method is suggested for predicting under what conditions these defects will be the most stable form of the donor impurity.
DX centers in III-V semiconductors under hydrostatic pressure
International Nuclear Information System (INIS)
DX centers are deep level defects found in some III-V semiconductors. They have persistent photoconductivity and large difference between thermal and optical ionization energies. Hydrostatic pressure was used to study microstructure of these defects. A new local vibrational mode (LVM) was observed in hydrostatically stressed, Si-doped GaAs. Corresponding infrared absorption peak is distinct from the SiGa shallow donor LVM peak, which is the only other LVM peak observed in our samples, and is assigned to the Si DX center. Analysis of the relative intensities of the Si DX LVM and the Si shallow donor LVM peaks, combined with Hall effect and resistivity indicate that the Si DX center is negatively charged. Frequency of this new mode provides clues to the structure of this defect. A pressure induced deep donor level in S-doped InP was also discovered which has the properties of a DX center. Pressure at which the new defect becomes more stable than the shallow donor is 82 kbar. Optical ionization energy and energy dependence of the optical absorption cross section was measured for this new effect. Capture barrier from the conduction band into the DX state were also determined. That DX centers can be formed in InP by pressure suggests that DX states should be common in n-type III-V semiconductors. A method is suggested for predicting under what conditions these defects will be the most stable form of the donor impurity
Innovative transient-proof hydrostatic level measuring method
International Nuclear Information System (INIS)
Most of the level monitoring systems for pressure vessels containing saturated steam-water mixture use the hydrostatic method. Differential pressure transducers are connected by pulse tubes with nozzles at different height of the pressure vessel. A disadvantage of this method is given by measuring errors caused by evaporation and/or degassing processes in vertical parts of these pulse lines. The error is caused by the decrease of the fluid density in the reference pipe, when a two-phase mixture appears. The present work aimed at the test of a novel differential pressure measuring system that eliminates the influence of density changes in the pulse lines. It is based on two differential pressure transducers, placed accurately at the elevation of the connecting nozzles. They are connected with the pressure vessel only by horizontal pipes. The vertical distance is bridged by a standpipe, the fluid of which is completely separated from the fluid in the vessel. Degassing respectively evaporation effects can therefore be completely excluded in the reference column of the new system. The method was tested at the pressurizer test facility of the University of Applied Sciences Zittau/Goertlitz, IPM on three types of transients including a rapid pressure decrease similar to a loss-of-coolant transient. Traditional differential pressure systems as well as local void probes were used for comparison. The method has proven its advantages compared to the traditional hydrostatic level measurement method. (orig.)
Photomultiplier tube failure under hydrostatic pressure in future neutrino detectors
International Nuclear Information System (INIS)
Failure of photomultiplier tubes (PMTs) under hydrostatic pressure is a concern in neutrino detection, specifically, in the proposed Long-Baseline Neutrino Experiment project. Controlled hydrostatic implosion tests were performed on prototypic PMT bulbs of 10-inch diameter and recorded using high speed filming techniques to capture failures in detail. These high-speed videos were analyzed frame-by-frame in order to identify the origin of a crack, measure the progression of individual crack along the surface of the bulb as it propagates through the glass, and estimate crack velocity. Crack velocity was calculated for each individual crack, and an average velocity was determined for all measurable cracks on each bulb. Overall, 32 cracks were measured in 9 different bulbs tested. Finite element modeling (FEM) of crack formation and growth in prototypic PMT shows stress concentration near the middle section of the PMT bulbs that correlates well with our crack velocity measurements in that section. The FEM model predicts a crack velocity value that is close to the terminal crack velocity reported. Our measurements also reveal significantly reduced crack velocities compared to terminal crack velocities measured in glasses using fracture mechanics testing and reported in literature
Testing hydrostatic equilibrium in galaxy cluster ms 2137
Chiu, I-Non; Chen, Pisin
2012-01-01
We test the assumption of strict hydrostatic equilibrium in galaxy cluster MS2137.3-2353 (MS 2137) using the latest CHANDRA X-ray observations and results from a combined strong and weak lensing analysis based on optical observations. We deproject the two-dimensional X-ray surface brightness and mass surface density maps assuming spherical and spheroidal dark matter distributions. We find a significant, 40%-50%, contribution from non-thermal pressure in the core assuming a spherical model. This non-thermal pressure support is similar to what was found by Molnar et al. (2010) using a sample of massive relaxed clusters drawn from high resolution cosmological simulations. We have studied hydrostatic equilibrium in MS 2137 under the assumption of elliptical cluster geometry adopting prolate models for the dark matter density distribution with different axis ratios. Our results suggest that the main effect of ellipticity (compared to spherical models) is to decrease the non-thermal pressure support required for eq...
Double nanoplate-based NEMS under hydrostatic and electrostatic actuations
Ebrahimi, Farzad; Hosseini, S. H. S.
2016-05-01
Presented herein is a comprehensive investigation on the nonlinear vibration behavior of nanoplate-based nano electromechanical systems (NEMS) under hydrostatic and electrostatic actuations based on nonlocal elasticity and Gurtin-Murdoch theory. Using nonlinear strain-displacement relations, the geometrical nonlinearity is modeled. Based on Kelvin-Voigt model, the influence of the viscoelastic coefficient is also discussed. Nonlocal plate theory and Hamilton's principle are utilized for deriving the governing equations. Furthermore, the differential quadrature method (DQM) is employed to compute the nonlinear frequency. In addition, pull-in voltage and hydrostatic pressure are considered by comparing the results obtained from nanoplates made of two different materials including aluminum (Al) and silicon (Si). Finally, the influences of important parameters including the small scale, thickness of the nanoplate, center gap and Winkler coefficient in the actuated nanoplate are thoroughly studied. The plots for the ratio of nonlinear-to-linear frequencies against thickness, maximum transverse amplitude and non-dimensional center gap of nanoplate are also presented.
Inelastic compaction, dilation and hysteresis of sandstones under hydrostatic conditions
Shalev, Eyal; Lyakhovsky, Vladimir; Ougier-Simonin, Audrey; Hamiel, Yariv; Zhu, Wenlu
2014-05-01
Sandstones display non-linear and inelastic behaviour such as hysteresis when subjected to cyclic loading. We present three hydrostatic compaction experiments with multiple loading-unloading cycles on Berea and Darley Dale sandstones and explain their hysteretic behaviour using non-linear inelastic compaction and dilation. Each experiment included eight to nine loading-unloading cycles with increasing maximum pressure in each subsequent cycle. Different pressure-volumetric strain relations during loading and unloading were observed. During the first cycles, under relatively low pressures, not all of the volumetric strain is recovered at the end of each cycle whereas at the last cycles, under relatively high pressures, the strain is recovered and the pressure-volumetric strain hysteresis loops are closed. The observed pressure-volumetric strain relations are non-linear and the effective bulk modulus of the sandstones changes between cycles. Observations are modelled with two inelastic deformation processes: irreversible compaction caused by changes in grain packing and recoverable compaction associated with grain contact adhesion, frictional sliding on grains or frictional sliding on cracks. The irreversible compaction is suggested to reflect rearrangement of grains into a more compact mode as the maximum pressure increases. Our model describes the `inelastic compaction envelope' in which sandstone sample will follow during hydrostatic loading. Irreversible compaction occurs when pressure is greater than a threshold value defined by the `inelastic compaction envelope'.
Study of glass hydrometer calibration by hydrostatic weighting
Chen, Chaoyun; Wang, Jintao; Li, Zhihao; Zhang, Peiman
2016-01-01
Glass hydrometers are simple but effective instruments for measuring the density of liquids. Glass hydrometers calibration based on the Archimedes law, using silicon ring as a reference standard solid density, n-tridecane with density stability and low surface tension as the standard working liquid, based on hydrostatic weighing method designs a glass hydrometer calibration system. Glass hydrometer calibration system uses CCD image measurement system to align the scale of hydrometer and liquid surface, with positioning accuracy of 0.01 mm. Surface tension of the working liquid is measured by Whihemy plate. According to twice glass hydrometer weighing in the air and liquid can calculate the correction value of the current scale. In order to verify the validity of the principle of the hydrostatic weighing method of glass hydrometer calibration system, for measuring the density range of (770-790) kg/m3, with a resolution of 0.2 kg/m3 of hydrometer. The results of measurement compare with the Physikalisch-Technische Bundesanstalt(PTB) ,verifying the validity of the calibration system.
Photomultiplier tube failure under hydrostatic pressure in future neutrino detectors
International Nuclear Information System (INIS)
Failure of photomultiplier tubes (PMTs) under hydrostatic pressure is a concern in neutrino detection, specifically, in the proposed Long-Baseline Neutrino Experiment (LBNE) project. Controlled hydrostatic implosion tests were performed on prototypic PMT bulbs of 10-inch diameter and recorded using high-speed filming techniques to capture failures in detail. These high-speed videos were analyzed frame-by-frame in order to identify the origin of a crack, measure the progression of individual crack along the surface of the bulb as it propagates through the glass, and estimate crack velocity. Crack velocity was calculated for each individual crack and an average velocity was determined for all measurable cracks on each bulb. Overall, 32 cracks were measured in 9 different bulbs tested. Finite element modeling (FEM) of crack formation and growth in prototypic PMT shows stress concentration near the middle section of the PMT bulbs that correlates well with our crack velocity measurements in that section. The FEM model predicts a crack velocity value that is close to the terminal crack velocity reported. Our measurements also reveal significantly reduced crack velocities compared to terminal crack velocities measured in glasses using fracture mechanics testing and reported in literature
Collapse of composite tubes under uniform external hydrostatic pressure
Smith, P. T.; Ross, C. T. F.; Little, A. P. F.
2009-08-01
This paper describes an experimental and a theoretical investigation into the collapse of 22 circular cylindrical composite tubes under external hydrostatic pressure. The investigations were on the collapse of fibre reinforced plastic tube specimens made from a mixture of three carbon and two E-glass fibre layers. The theoretical investigations were carried out using an in-house finite element computer program called BCLAM, together with the commercial computer package, namely ANSYS. It must be emphasised here that BS 5500 does not appear to exclusively cater for the buckling of composite shells under external hydrostatic pressure, so the work presented here is novel and should be useful to industry. The experimental investigations showed that the composite specimens behaved similarly to isotropic materials previously tested, in that the short vessels collapsed through axisymmetric deformation while the longer tubes collapsed through non-symmetric bifurcation buckling. Furthermore it was discovered that the models failed at changes of the composite lay-up due to the manufacturing process of these models. These changes seemed to be the weak points of the specimens.
Long, Fan; Ganesh, Vijay; Carbin, Michael James; Sidiroglou, Stelios; Rinard, Martin
2012-01-01
We present a novel technique, automatic input rectification, and a prototype implementation, SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process correctly. When given an atypical input that does not satisfy these constraints, SOAP automatically rectifies the input (i.e., changes the input so that it satisfies the learned constraints). The goal is to automatically convert potentially dangerous inputs into typical inputs that the ...
Directory of Open Access Journals (Sweden)
Narcis Eduard Mitu
2013-11-01
Full Text Available Policies or institutions (built into an economic system that automatically tend to dampen economic cycle fluctuations in income, employment, etc., without direct government intervention. For example, in boom times, progressive income tax automatically reduces money supply as incomes and spendings rise. Similarly, in recessionary times, payment of unemployment benefits injects more money in the system and stimulates demand. Also called automatic stabilizers or built-in stabilizers.
Automatic differentiation bibliography
Energy Technology Data Exchange (ETDEWEB)
Corliss, G.F. (comp.)
1992-07-01
This is a bibliography of work related to automatic differentiation. Automatic differentiation is a technique for the fast, accurate propagation of derivative values using the chain rule. It is neither symbolic nor numeric. Automatic differentiation is a fundamental tool for scientific computation, with applications in optimization, nonlinear equations, nonlinear least squares approximation, stiff ordinary differential equation, partial differential equations, continuation methods, and sensitivity analysis. This report is an updated version of the bibliography which originally appeared in Automatic Differentiation of Algorithms: Theory, Implementation, and Application.
Dynamic transmission response of a hydrostatic transmission measured on a test bench
Schmitz, J.; Diepeveen, N.F.B.; Vatheuer, N.; Murrenhoff, H.
2012-01-01
Within the scope of a current research project a hydrostatic transmission for wind turbines is being developed at IFAS. In this paper, two different strategies to control a hydrostatic transmission in wind turbines are presented and discussed. Main criteria are the optimal adaption of the system to
Effect of high hydrostatic pressure on overall quality parameters of watermelon juice.
Liu, Y; Zhao, X Y; Zou, L; Hu, X S
2013-06-01
High hydrostatic pressure as a kind of non-thermal processing might maintain the quality of thermo-sensitive watermelon juice. So, the effect of high hydrostatic pressure treatment on enzymes and quality of watermelon juice was investigated. After high hydrostatic pressure treatment, the activities of polyphenol oxidase, peroxidase, and pectin methylesterase of juice decreased significantly with the pressure (P pectin methylesterase could be described by first-order reaction model. Titratable acidity, pH, and total soluble solid of juice did not change significantly (P > 0.05). No significant difference was observed in lycopene and total phenolics after high hydrostatic pressure treatment when compared to the control (P > 0.05). Cloudiness and viscosity increased with pressure (P treatment time (P > 0.05). a*- and b*-value both unchanged after high hydrostatic pressure treatment (P > 0.05) while L*-value increased but the values had no significant difference among treated juices. Browning degree after high hydrostatic pressure treatment decreased with increase in pressure and treatment time (P < 0.05). Through the comparison of total color difference values, high hydrostatic pressure had little effect on color of juice. The results of this study demonstrated the efficacy of high hydrostatic pressure in inactivating enzymes and maintaining the quality of watermelon juice. PMID:23493787
Development of methods and equipment for bellows assemblies testing under hydrostatic pressure
Ol’khovik, E.
2016-04-01
The paper presents a newbellows assemblies test method for stop and safety valves. To create the real conditions it is suggested testing under external hydrostatic pressure, which is available in the piping system.A designed test apparatus allows testing of the bellows under the effect of external hydrostatic pressure. The paper describes the design of the apparatus, its specifications and the test procedures.
2013-11-25
... Act of 1995 (44 U.S.C. 3506 et seq.) and Secretary of Labor's Order No. 1-2012 (77 FR 3912). Signed at... Occupational Safety and Health Administration Thy Hydrostatic Testing Provision of the Portable Fire... contained in the Hydrostatic Testing provision of the Portable Fire Extinguishers Standard for...
46 CFR 54.10-10 - Standard hydrostatic test (modifies UG-99).
2010-10-01
... Boiler and Pressure Vessel Code (incorporated by reference, see 46 CFR 54.01-1). The value of “S” at test... 46 Shipping 2 2010-10-01 2010-10-01 false Standard hydrostatic test (modifies UG-99). 54.10-10... PRESSURE VESSELS Inspection, Reports, and Stamping § 54.10-10 Standard hydrostatic test (modifies...
2010-08-11
... Order No. 5-2007 (72 FR 31160). Signed at Washington, DC, this 6th day of August 2010. David Michaels... Occupational Safety and Health Administration The Hydrostatic Testing Provision of the Portable Fire... the Hydrostatic Testing provision of the Portable Fire Extinguishers Standard for General Industry...
Direct Georeferencing of Stationary LiDAR
Ahmed Mohamed; Benjamin Wilkinson
2009-01-01
Unlike mobile survey systems, stationary survey systems are given very little direct georeferencing attention. Direct Georeferencing is currently being used in several mobile applications, especially in terrestrial and airborne LiDAR systems. Georeferencing of stationary terrestrial LiDAR scanning data, however, is currently performed indirectly through using control points in the scanning site. The indirect georeferencing procedure is often troublesome; the availability of control stations w...
Adaptive covariance estimation of locally stationary processes
Mallat, Stéphane; Papanicolaou, George; Zhang, Zhifeng
1998-01-01
It is shown that the covariance operator of a locally stationary process has approximate eigenvectors that are local cosine functions. We model locally stationary processes with pseudo-differential operators that are time-varying convolutions. An adaptive covariance estimation is calculated by searching first for a "best" local cosine basis which approximates the covariance by a band or a diagonal matrix. The estimation is obtained from regularized versions of the diagonal coefficients in the...
Self-Organized Stationary States of Tokamaks.
Jardin, S C; Ferraro, N; Krebs, I
2015-11-20
We demonstrate that in a 3D resistive magnetohydrodynamic simulation, for some parameters it is possible to form a stationary state in a tokamak where a saturated interchange mode in the center of the discharge drives a near helical flow pattern that acts to nonlinearly sustain the configuration by adjusting the central loop voltage through a dynamo action. This could explain the physical mechanism for maintaining stationary nonsawtoothing "hybrid" discharges, often referred to as "flux pumping." PMID:26636854
Self-Organized Stationary States of Tokamaks
Energy Technology Data Exchange (ETDEWEB)
Jardin, S. C. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Ferraro, N. [General Atomics, San Diego, CA (United States); Krebs, I. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Max-Plank-Institut fur Plasmaphysik, Garching, Germany
2015-11-01
We demonstrate that in a 3D resistive magnetohydrodynamic simulation, for some parameters it is possible to form a stationary state in a tokamak where a saturated interchange mode in the center of the discharge drives a near helical flow pattern that acts to nonlinearly sustain the configuration by adjusting the central loop voltage through a dynamo action. This could explain the physical mechanism for maintaining stationary nonsawtoothing "hybrid" discharges, often referred to as "flux pumping."
Stationary Liquid Fuel Fast Reactor
International Nuclear Information System (INIS)
For effective burning of hazardous transuranic (TRU) elements of used nuclear fuel, a transformational advanced reactor concept named SLFFR (Stationary Liquid Fuel Fast Reactor) was proposed based on stationary molten metallic fuel. The fuel enters the reactor vessel in a solid form, and then it is heated to molten temperature in a small melting heater. The fuel is contained within a closed, thick container with penetrating coolant channels, and thus it is not mixed with coolant nor flow through the primary heat transfer circuit. The makeup fuel is semi- continuously added to the system, and thus a very small excess reactivity is required. Gaseous fission products are also removed continuously, and a fraction of the fuel is periodically drawn off from the fuel container to a processing facility where non-gaseous mixed fission products and other impurities are removed and then the cleaned fuel is recycled into the fuel container. A reference core design and a preliminary plant system design of a 1000 MWt TRU- burning SLFFR concept were developed using TRU-Ce-Co fuel, Ta-10W fuel container, and sodium coolant. Conservative design approaches were adopted to stay within the current material performance database. Detailed neutronics and thermal-fluidic analyses were performed to develop a reference core design. Region-dependent 33-group cross sections were generated based on the ENDF/B-VII.0 data using the MC2-3 code. Core and fuel cycle analyses were performed in theta-r-z geometries using the DIF3D and REBUS-3 codes. Reactivity coefficients and kinetics parameters were calculated using the VARI3D perturbation theory code. Thermo-fluidic analyses were performed using the ANSYS FLUENT computational fluid dynamics (CFD) code. Figure 0.1 shows a schematic radial layout of the reference 1000 MWt SLFFR core, and Table 0.1 summarizes the main design parameters of SLFFR-1000 loop plant. The fuel container is a 2.5 cm thick cylinder with an inner radius of 87.5 cm. The fuel
Stationary Liquid Fuel Fast Reactor
Energy Technology Data Exchange (ETDEWEB)
Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States); Grandy, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Boroski, Andrew [Argonne National Lab. (ANL), Argonne, IL (United States); Krajtl, Lubomir [Argonne National Lab. (ANL), Argonne, IL (United States); Johnson, Terry [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-09-30
For effective burning of hazardous transuranic (TRU) elements of used nuclear fuel, a transformational advanced reactor concept named SLFFR (Stationary Liquid Fuel Fast Reactor) was proposed based on stationary molten metallic fuel. The fuel enters the reactor vessel in a solid form, and then it is heated to molten temperature in a small melting heater. The fuel is contained within a closed, thick container with penetrating coolant channels, and thus it is not mixed with coolant nor flow through the primary heat transfer circuit. The makeup fuel is semi- continuously added to the system, and thus a very small excess reactivity is required. Gaseous fission products are also removed continuously, and a fraction of the fuel is periodically drawn off from the fuel container to a processing facility where non-gaseous mixed fission products and other impurities are removed and then the cleaned fuel is recycled into the fuel container. A reference core design and a preliminary plant system design of a 1000 MWt TRU- burning SLFFR concept were developed using TRU-Ce-Co fuel, Ta-10W fuel container, and sodium coolant. Conservative design approaches were adopted to stay within the current material performance database. Detailed neutronics and thermal-fluidic analyses were performed to develop a reference core design. Region-dependent 33-group cross sections were generated based on the ENDF/B-VII.0 data using the MC2-3 code. Core and fuel cycle analyses were performed in theta-r-z geometries using the DIF3D and REBUS-3 codes. Reactivity coefficients and kinetics parameters were calculated using the VARI3D perturbation theory code. Thermo-fluidic analyses were performed using the ANSYS FLUENT computational fluid dynamics (CFD) code. Figure 0.1 shows a schematic radial layout of the reference 1000 MWt SLFFR core, and Table 0.1 summarizes the main design parameters of SLFFR-1000 loop plant. The fuel container is a 2.5 cm thick cylinder with an inner radius of 87.5 cm. The fuel
Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing
International Nuclear Information System (INIS)
Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests
Investigating the nucleation of protein crystals with hydrostatic pressure
International Nuclear Information System (INIS)
Hydrostatic pressure in the 0.1-75 MPa range has been used as a non-invasive tool to study the crystallization process of the tetragonal crystal form of the protein thaumatin (Mr 22 200). Crystals were prepared within agarose gel and at temperatures in the range from 283 to 303 K. The solubility, i.e. the concentration of soluble macromolecules remaining in equilibrium with the crystals, decreases when the pressure increases and when the temperature decreases. High pressure was used to probe the nucleation behaviour of thaumatin. The pressure dependence of the nucleation rate leads to an activation volume of -46.5cm3 mol-1. It is shown that an increase in pressure decreases the enthalpy, the entropy and the free energy of crystallization of thaumatin. The data are discussed in the light of the results of crystallographic analyses and of the structure of the protein
Multi-Pulsed High Hydrostatic Pressure Treatment of Foods
Directory of Open Access Journals (Sweden)
Sencer Buzrul
2015-05-01
Full Text Available Multi-pulsed high hydrostatic pressure (mpHHP treatment of foods has been investigated for more than two decades. It was reported that the mpHHP treatment, with few exceptions, is more effective than the classical or single-pulsed HHP (spHHP treatment for inactivation of microorganisms in fruit juice, dairy products, liquid whole egg, meat products, and sea foods. Moreover, the mpHHP treatment could be also used to inactivate enzymes in foods and to increase the shelf-life of foods. The effects of the mpHHP treatment of foods are summarized and the differences between the mpHHP and spHHP are also emphasized.
Damage Characterization in Copper Deformed under Hydrostatic Stress - Experimental Analysis
International Nuclear Information System (INIS)
The results of an experimental investigation designed to determine the effect of damage created by hydrostatic tensile loading on the properties of copper are reported. Three metallurgical conditions of half-hard OFHC copper were investigated; as worked; annealed 2hr at 400 deg. C (∼40 micron grain diameter); and annealed 2hr at 800 deg. C (∼80 micron grain diameter). Mechanical property characterization included uniaxial compression tests. High rate plasticity and damage was introduced by Taylor and rod-on-rod impact tests. The damage from the high rate experiments was characterized using optical and scanning electron microscopy. Quasi-static compression specimens machined from recovered high rate samples were tested to determine the influence of damage on the mechanical response of the material. The compression test results will be discussed in relationship to the starting microstructure and the extent of damaged introduced into the material
Installation and debugging of the hydrostatic leveling system at SSRF
International Nuclear Information System (INIS)
In this paper, we discuss the technical problems during installation and debugging of the hydrostatic leveling system (HLS) established on the linac, booster and storage ring of Shanghai Synchrotron Radiation Facility (SSRF), and the ways to solve the problems. Before the system installation, all the sensors were tested to exclude anyone that failed, because of the reasons of transportation, to meet the accuracy requirement of the SSRF design. The test method and test process are given in detail. During the process of HLS system installation, we solved a number of problems that could not be anticipated, e.g problems of the supports and water supplying. The surveying results after system installation show that the system works normally and satisfies the designing requirement. (authors)
Photoionized gas in hydrostatic equilibrium: the role of gravity
Ascasibar, Y
2010-01-01
We present a method to include the effects of gravity in the plasma physics code Cloudy. More precisely, a term is added to the desired gas pressure in order to enforce hydrostatic equilibrium, accounting for both the self-gravity of the gas and the presence of an optional external potential. As a test case, a plane-parallel model of the vertical structure of the Milky Way disk near the solar neighbourhood is considered. It is shown that the gravitational force determines the scale height of the disk, and it plays a critical role in setting its overall chemical composition. However, other variables, such as the shape of incident continuum and the intensity of the Galactic magnetic field, strongly affect the predicted structure.
Role of osmotic and hydrostatic pressures in bacteriophage genome ejection
Lemay, Serge G.; Panja, Debabrata; Molineux, Ian J.
2013-02-01
A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly in vitro, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution or culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection in vivo; the mechanism is perfectly consistent with phage genome ejection in vitro.
Role of osmotic and hydrostatic pressures in bacteriophage genome ejection
Lemay, Serge G; Molineux, Ian J
2012-01-01
A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly \\textit{in vitro}, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution/culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection \\textit{in vivo}; the mechanism is perfectly consistent with phage genome ejection \\textit{in vitro}.
Hydrostatic equilibrium and stellar structure in f(R)-gravity
Capozziello, S; Odintsov, S D; Stabile, A
2011-01-01
We investigate the hydrostatic equilibrium of stellar structure by taking into account the modi- fied La\\'e-Emden equation coming out from f(R)-gravity. Such an equation is obtained in metric approach by considering the Newtonian limit of f(R)-gravity, which gives rise to a modified Poisson equation, and then introducing a relation between pressure and density with polytropic index n. The modified equation results an integro-differential equation, which, in the limit f(R) \\rightarrow R, becomes the standard La\\'e-Emden equation. We find the radial profiles of gravitational potential by solving for some values of n. The comparison of solutions with those coming from General Relativity shows that they are compatible and physically relevant.
Numerical and Experimental Study of Friction Loss in Hydrostatic Motor
DEFF Research Database (Denmark)
Sørensen, Rasmus Mørk; Hansen, Michael R.; Mouritsen, Ole Ø.
2012-01-01
This paper presents a numerical and experimental study of the losses in a hydrostatic motor principle. The motor is designed so that the structural de ections and lubricating regimes between moving surfaces and, subsequently, the leakage and friction losses, can be controlled during operation. This...... is done by means of additional pressure volumes that in uence the stator de ection. These pressures are referred to as compensation pressures and the main emphasis is on friction or torque loss modeling of the motor as a function of the compensation pressures and the high and low pressures related to...... the load torque. The torque loss modeling is identied as a Stribeck curve which depends on gap height. The asperity friction is decreasing exponentially with an increase in gap height. The parameters of the torque loss model are based on prototype measurements that include the structural de ections of...
Ultrahigh hydrostatic pressure extraction of flavonoids from Epimedium koreanum Nakai
Hou, Lili; Zhang, Shouqin; Dou, Jianpeng; Zhu, Junjie; Liang, Qing
2011-02-01
Herba Epimedii is one of the most famous Chinese herbal medicines listed in the Pharmacopoeia of the People's Republic of China, as one of the representatives of traditional Chinese herb, it has been widely applied in the field of invigorate the kidney and strengthen 'Yang'. The attention to Epimedium extract has more and more increased in recent years. In this work, a novel extraction technique, ultra-high hydrostatic pressure extraction (UPE) technology was applied to extract the total flavonoids of E. koreanum. Three factors (pressure, ethanol concentration and extraction time) were chosen as the variables of extraction experiments, and the optimum UPE conditions were pressure 350 MPa; ethanol concentration 50% (v/v); extraction time 5 min. Compared with Supercritical CO2 extraction, Reflux extraction and Ultrasonic-assisted extraction, UPE has excellent advantages (shorter extraction time, higher yield, better antioxidant activity, lower energy consumption and eco-friendly).
Effect of hydrostatic pressure on elastic properties of ZDTP tribofilms
Demmou, Karim; Loubet, Jean-Luc
2007-01-01
Previous studies have shown that the elastic properties of Zinc Dialkyl-dithiophosphate (ZDTP) tribofilms measured by nanoindentation increase versus applied pressure (Anvil effect) [1, 2]. The aim of this paper is to demonstrate that, up to 8 GPa, this increase is a reversible phenomenon. A ZDTP tribofilm has been produced on "AISI 52100" steel substrate using a Cameron-Plint tribometer. After its formation, a hydrostatic pressure of about 8 GPa was applied during one minute on the tribofilm using a large radius steel ball ("Brinell-like" test). Nanoindentation tests were performed with a Berkovich tip on pads in order to measure and compare the mechanical properties of the tribofilm inside and outside the macroscopic plastically deformed area. Careful AFM observations have been carried out on each indent in order to take into account actual contact area. No difference in elastic properties was observed between the two areas: tribofilm modulus and pressure sensitivity are the same inside and outside the resi...
APPLICATIONS OF HIGH HYDROSTATIC PRESSURE IN THE FOOD INDUSTRY
Directory of Open Access Journals (Sweden)
Yahya TÜLEK
2006-03-01
Full Text Available Nowadays, thermal processes are used in order to preserve food from microbiologic and enzymatic changes and extend the shelf life. Thermal treatments are particularly safe, assures a total inactivation of vegetative microorganism cells and spore. On the other hand it present some disadvantages related to the high temperature employed, such as denaturation of proteins, vitamins, productions of toxic compound, undesirable organoleptic features. The last decade, non-thermal inactivation techniques have been a major research issue, driven by an increased consumer demand for nutritious, fresh like food products with a high organoleptical quality and an acceptable shelf life. Present article represents studies on application aspects and effects of high hydrostatic pressure in foods.
On the Nature of Hydrostatic Equilibrium in Galaxy Clusters
Biffi, V.; Borgani, S.; Murante, G.; Rasia, E.; Planelles, S.; Granato, G. L.; Ragone-Figueroa, C.; Beck, A. M.; Gaspari, M.; Dolag, K.
2016-08-01
In this paper, we investigate the level of hydrostatic equilibrium (HE) in the intracluster medium of simulated galaxy clusters, extracted from state-of-the-art cosmological hydrodynamical simulations performed with the Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several physical processes, among which are stellar and active galactic nucleus feedback, and have been performed with an improved version of the code that allows for a better description of hydrodynamical instabilities and gas mixing processes. Evaluating the radial balance between the gravitational and hydrodynamical forces via the gas accelerations generated, we effectively examine the level of HE in every object of the sample and its dependence on the radial distance from the center and on the classification of the cluster in terms of either cool-coreness or dynamical state. We find an average deviation of 10%–20% out to the virial radius, with no evident distinction between cool-core and non-cool-core clusters. Instead, we observe a clear separation between regular and disturbed systems, with a more significant deviation from HE for the disturbed objects. The investigation of the bias between the hydrostatic estimate and the total gravitating mass indicates that, on average, this traces the deviation from HE very well, even though individual cases show a more complex picture. Typically, in the radial ranges where mass bias and deviation from HE are substantially different, the gas is characterized by a significant amount of random motions (≳ 30 % ), relative to thermal ones. As a general result, the HE-deviation and mass bias, at a given distance from the cluster center, are not very sensitive to the temperature inhomogeneities in the gas.
Thermal stability of hydrostatically extruded EUROFER 97 steel
International Nuclear Information System (INIS)
EUROFER 97 steel is a candidate structural material for the future fusion power reactors, as well as for the European Test Blanket Modules (TBMs) to be tested in ITER. In the reported study, the microstructure of EUROFER 97 was modified by hydrostatic extrusion (HE) which reduced the grain size from 400 to 86 nm and that of the carbide particles from 111 to 75 nm. The changes in the microstructure significantly improved the strength of the extruded samples. However, it is important that the enhanced properties of nanostructured materials are stable over the required range of intended service temperature. The thermal stability of the nanostructured EUROFER steel was evaluated by subjecting the hydrostatically extruded samples to annealing at temperatures ranging from 473 to 1073 K (200-800 deg. C) for 1 h. Tensile tests and microhardness measurements with a 200 g load were carried out on the annealed samples to determine the effect of the heat treatment. The results show that the highest microhardness (403 HV0.2) was achieved for samples annealed at 673 K. However, the tensile and yield strength decreased at the higher temperature of 873 K and the total elongation increased to 15%, compared to only 3% for as-extruded samples. The changes in the mechanical properties were rationalized by the examination of the microstructural changes. During heating the initial grain size remains virtually unchanged below a temperature of 873 K. However, above 873 K the grain size increased and it is very likely that growth will be very rapid at higher temperatures.
Thermal conductivity and compressive strain of foam neoprene insulation under hydrostatic pressure
International Nuclear Information System (INIS)
The purpose of this study was to show that the thermal properties of foam neoprene under hydrostatic pressure cannot be predicted by theoretical means, and that uni-axial pressure cannot simulate hydrostatic compression. The thermal conductivity and compressive strain of foam neoprene were measured under hydrostatic pressure. In parallel, uni-axial compressive strain data were collected. The experimental set-up and data were put into perspective with past published studies. It was shown that uni-axial compression yielded strains 20-25% greater than did hydrostatic compression. This suggests the need for direct hydrostatic pressure measurement. For comparison to hydrostatic experimental data, a series of thermal conductivity theories of two phase composites based on particulate phase geometry were utilized. Due to their dependence on the porosity and constituent thermal conductivities, a model to predict porosity under hydrostatic pressure was used and an empirical correlation was derived to calculate the thermal conductivity of pure neoprene rubber from experimental data. It was shown that, although some agreement between experimental data and thermal conductivity theories was present, no particular theory can be used because they all fail to model the complex structure of the pores. It was therefore concluded that an experimental programme, such as reported here, is necessary for direct measurement
DuRaine, G D; Athanasiou, K.A.
2012-01-01
The objective of this study was to identify the ERK 1/2 involvement in the changes in compressive and tensile mechanical properties associated with hydrostatic pressure treatment of self-assembled cartilage constructs. In study 1, ERK 1/2 phosphorylation was detected by immunoblot following application of hydrostatic pressure (1 hour of static 10MPa) applied at day 10-14 of self-assembly culture. In study 2, ERK 1/2 activation was blocked during hydrostatic pressure application on days 10-14....
Full Counting Statistics of Stationary Particle Beams
Kiukas, J; Werner, R F
2010-01-01
We present a general scheme for treating particle beams, including stationary beams, as many particle systems. This includes the full counting statistics and the requirements of Bose/Fermi symmetry. We treat in detail a model of a source, creating particles in a fixed state, which then evolve under the free time evolution, and we determine the resulting stationary beam in the far field. In comparison to the one-particle picture we obtain a correction from Bose/Fermi statistics, which depends on the emission rate.
Stationary Scalar Clouds Around Rotating Black Holes
Hod, Shahar
2012-01-01
Motivated by novel results in the theory of wave dynamics in black-hole spacetimes, we analyze the dynamics of a massive scalar field surrounding a rapidly rotating Kerr black hole. In particular, we report on the existence of stationary (infinitely long-lived) regular field configurations in the background of maximally rotating black holes. The effective height of these scalar "clouds" above the central black hole is determined analytically. Our results support the possible existence of stationary scalar field dark matter distributions surrounding rapidly rotating black holes.
Structure of stationary and axisymmetric metrics
International Nuclear Information System (INIS)
We study the structure of stationary and axisymmetric metrics solving the vacuum Einstein equations of general relativity in four and higher dimensions, building on recent work in Phys. Rev. D 70, 124002 (2004). We write the Einstein equations in a new form that naturally identifies the sources for such metrics. The sources live in a one-dimensional subspace and the entire metric is uniquely determined by them. We study in detail the structure of stationary and axisymmetric metrics in four dimensions, and consider as an example the sources of the Kerr black hole
Stationary occultations from low Earth orbit
Percival, Jeffrey W.
1993-01-01
The process of stationary lunar occultations is considered for observers in LEO. The orbit of the Hubble Space Telescope (HST) is used as a prototype. The noncoplanarity of the HST and lunar orbits disrupts many of the expected stationary events, and orbital drag complicates the prediction problem. In a typical year, the apparent speed of the lunar limb seen by the HST is slower than a typical ground-based event only about 0.7 percent of the time. The orbit prediction can be wrong by as much as 20 deg in 53 days, with most of the error lying in the plane of the orbit.
Automatic Implantable Cardiac Defibrillator
Full Text Available Automatic Implantable Cardiac Defibrillator February 19, 2009 Halifax Health Medical Center, Daytona Beach, FL Welcome to Halifax Health Daytona Beach, Florida. Over the next hour you' ...
Automatic Payroll Deposit System.
Davidson, D. B.
1979-01-01
The Automatic Payroll Deposit System in Yakima, Washington's Public School District No. 7, directly transmits each employee's salary amount for each pay period to a bank or other financial institution. (Author/MLF)
Automatic Arabic Text Classification
Al-harbi, S; Almuhareb, A.; Al-Thubaity , A; Khorsheed, M. S.; Al-Rajeh, A.
2008-01-01
Automated document classification is an important text mining task especially with the rapid growth of the number of online documents present in Arabic language. Text classification aims to automatically assign the text to a predefined category based on linguistic features. Such a process has different useful applications including, but not restricted to, e-mail spam detection, web page content filtering, and automatic message routing. This paper presents the results of experiments on documen...
Charged particle tunnels from the stationary and non-stationary Kerr-Newman black holes
Chen, Deyou; Yang, Shuzheng
2007-09-01
Considering the unfixed background space-time and self-gravitational interaction, we view the Hawking radiation of a stationary Kerr-Newman black hole by Hamilton-Jacobi method. Meanwhile, extending this work to non-stationary black holes, we attempt to investigate the Hawking radiation of the non-stationary Kerr-Newman black hole. Both of the results show the tunneling probabilities are related to the change of Bekenstein- Hawking entropy and the radiation spectrums deviate from the purely thermal one, which is in accordance with the known result.
Markov Chains with Stochastically Stationary Transition Probabilities
Orey, Steven
1991-01-01
Markov chains on a countable state space are studied under the assumption that the transition probabilities $(P_n(x,y))$ constitute a stationary stochastic process. An introductory section exposing some basic results of Nawrotzki and Cogburn is followed by four sections of new results.
Danish emission inventories for stationary combustion plants
DEFF Research Database (Denmark)
Nielsen, Malene; Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt
Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are SO2, NOx, NMVOC, CH4, CO, CO2, N2O, NH3, particulate matter, heavy metals, PCDD/F, HCB and PAH. The CO2 emission in 2011...
Danish emission inventories for stationary combustion plants
DEFF Research Database (Denmark)
Nielsen, Malene; Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt;
Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are SO2, NOx, NMVOC, CH4, CO, CO2, N2O, NH3, particulate matter, heavy metals, dioxins, HCB and PAH. The CO2 emission in 2008...
Danish emission inventories for stationary combustion plants
DEFF Research Database (Denmark)
Nielsen, Malene; Nielsen, Ole-Kenneth; Plejdrup, Marlene Schmidt;
Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are SO2, NOx, NMVOC, CH4, CO, CO2, N2O, particulate matter, heavy metals, dioxins, HCB and PAH. The CO2 emission in 2007 was 10...
Surrogate data for non-stationary signals
Schmitz, A; Schmitz, Andreas; Schreiber, Thomas
1999-01-01
Standard tests for nonlinearity reject the null hypothesis of a Gaussian linear process whenever the data is non-stationary. Thus, they are not appropriate to distinguish nonlinearity from non-stationarity. We address the problem of generating proper surrogate data corresponding to the null hypothesis of an ARMA process with slowly varying coefficients.
Stationary Double Layers in a Collisionless Magnetoplasma
DEFF Research Database (Denmark)
Noriyoshi, Sato; Mieno, Tetsu; Hatakeyama, Rikizo;
1983-01-01
plate on the low-potential side, being accompanied with current limitation. This localized potential drop moves along the plasma column, but finally stops and results in the formation of the stationary double layer in the presence of sufficient plasma supply from the plate on the high-potential side....
Polarization fluctuations in stationary light beams
International Nuclear Information System (INIS)
For stationary beams the degree of polarization contains only limited information on time dependent polarization. Two approaches towards assessing a beams polarization dynamics, one based on Poincare and the other on Jones vector formalism, are described leading to the notion of polarization time. Specific examples of partially temporally coherent electromagnetic beams are discussed. (Author)
Damping device for a stationary labyrinth seal
El-Aini, Yehia M. (Inventor); Mitchell, William S. (Inventor); Roberts, Lawrence P. (Inventor); Montgomery, Stuart K. (Inventor); Davis, Gary A. (Inventor)
2010-01-01
A stationary labyrinth seal system includes a seal housing having an annular cavity, a plurality of damping devices, and a retaining ring. The damping devices are positioned within the annular cavity and are maintained within the annular cavity by the retaining ring.
What is "stationary" deformation of pure Cu?
Czech Academy of Sciences Publication Activity Database
Blum, W.; Dvořák, Jiří; Král, Petr; Eisenlohr, P.; Sklenička, Václav
2014-01-01
Roč. 49, č. 8 (2014), s. 2987-2997. ISSN 0022-2461 R&D Projects: GA ČR(CZ) GAP108/11/2260 Institutional support: RVO:68081723 Keywords : creep * Cu * recrystallization * stationary deformation resistances Subject RIV: JJ - Other Materials Impact factor: 2.371, year: 2014
The General Stationary Gaussian Markov Process
Brown, Larry; Ernst, Philip; Shepp, Larry; Wolpert, Bob
2013-01-01
We find the class, ${\\cal{C}}_k, k \\ge 0$, of all zero mean stationary Gaussian processes, $Y(t), ~t \\in \\reals$ with $k$ derivatives, for which \\begin{equation} Z(t) \\equiv (Y^{(0)}(t), Y^{(1)}(t), \\ldots, Y^{(k)}(t) ), ~ t \\ge 0 \\end{equation} \
Martizzi, Davide
2016-01-01
Galaxy cluster mass determinations achieved using X-ray and Sunyaev-Zeldovich data combined with the assumption of hydrostatic equilibrium are generally biased. The bias exists for two main reasons: non-thermal pressure forces are expected to contribute to the overall pressure balance and deviations from spherical symmetry and hydrostatic equilibrium can be present. In this paper, we use a sample of zoom-in hydrodynamical simulations of galaxy clusters to measure the magnitude of hydrostatic bias and the contribution from turbulence to the total pressure. We propose a new empirical model for turbulent pressure based on our simulations that can be applied to observations. We show that our model can be successfully applied to remove most of the bias related to neglection of turbulent pressure, which is usually not included in hydrostatic cluster mass profile reconstructions. The use of this model may significantly improve the calibration of cluster scaling relations that are a key tool for cluster cosmology.
II-VI wide band gap semiconductors under hydrostatic pressure
International Nuclear Information System (INIS)
We set an analytical expression for the gap as a function of hydrostatic deformation, Eg(ε), by diagonalizing in Γ the corresponding Empirical Tight-binding Hamiltonian (ETBH). In our ETBH we use the well known d-2 Harrison Scaling Law (HSL) to adjust the TB parameter (TBP) to the changes in interatomic distances. We do not consider cation-anion charge transfer. We calculate Eg(ε) for wide band gap II-VI semiconductors with zincblende crystal structure for deformations under pressure up to -5%. Our results are in quite good agreement with experiment for the compounds of lower ionicity but deviate as the ionicity of the compound increases. This is due to the neglect of charge transfer which should be included self-consistently as done, for example, by Bertho et al. starting from an Empirical Tight-binding description of the bands similar as the one presented here. They sometimes get nevertheless a negative second derivative of Eg(ε) with respect to ε which is never gotten in the experiments. Within our approximation we always find a positive sing independently of the material. It seems that the procedure in which self-consistency is achieved is the source of this wrong sign. Furthermore, the inclusion of deviations from HSL appear to be unimportant to this problem. (author). 15 refs, 4 figs, 2 tabs
On the nature of hydrostatic equilibrium in galaxy clusters
Biffi, V; Murante, G; Rasia, E; Planelles, S; Granato, G L; Ragone-Figueroa, C; Beck, A M; Gaspari, M; Dolag, K
2016-01-01
In this paper we investigate the level of hydrostatic equilibrium (HE) in the intra-cluster medium of simulated galaxy clusters, extracted from state-of-the-art cosmological hydrodynamical simulations performed with the Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several physical processes, among which stellar and AGN feedback, and have been performed with an improved version of the code that allows for a better description of hydrodynamical instabilities and gas mixing processes. Evaluating the radial balance between the gravitational and hydrodynamical forces, via the gas accelerations generated, we effectively examine the level of HE in every object of the sample, its dependence on the radial distance from the center and on the classification of the cluster in terms of either cool-coreness or dynamical state. We find an average deviation of 10-20% out to the virial radius, with no evident distinction between cool-core and non-cool-core clusters. Instead, we observe a clear separ...
Optimization of hydrostatic transmissions by means of virtual instrumentation technique
Ion Guta, Dragos Daniel; Popescu, Teodor Costinel; Dumitrescu, Catalin
2010-11-01
Obtaining mathematical models, as close as possible to physical phenomena which are intended to be replicated or improved, help us in deciding how to optimize them. The introduction of computers in monitoring and controlling processes caused changes in technological systems. With support from the methods for identification of processes and from the power of numerical computing equipment, researchers and designers can shorten the period for development of applications in various fields by generating a solution as close as possible to reality, since the design stage [1]. The paper presents a hybrid solution of modeling / simulation of a hydrostatic transmission with mixed adjustment. For simulation and control of the examined process we have used two distinct environments, AMESim and LabVIEW. The proposed solution allows coupling of the system's model to the software control modules developed using virtual instrumentation. Simulation network of the analyzed system was "tuned" and validated by an actual model of the process. This paper highlights some aspects regarding energy and functional advantages of hydraulic transmissions based on adjustable volumetric machines existing in their primary and secondary sectors [2].
Recent Advances in Food Processing Using High Hydrostatic Pressure Technology.
Wang, Chung-Yi; Huang, Hsiao-Wen; Hsu, Chiao-Ping; Yang, Binghuei Barry
2016-03-11
High hydrostatic pressure is an emerging non-thermal technology that can achieve the same standards of food safety as those of heat pasteurization and meet consumer requirements for fresher tasting, minimally processed foods. Applying high-pressure processing can inactivate pathogenic and spoilage microorganisms and enzymes, as well as modify structures with little or no effects on the nutritional and sensory quality of foods. The U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) have approved the use of high-pressure processing (HPP), which is a reliable technological alternative to conventional heat pasteurization in food-processing procedures. This paper presents the current applications of HPP in processing fruits, vegetables, meats, seafood, dairy, and egg products; such applications include the combination of pressure and biopreservation to generate specific characteristics in certain products. In addition, this paper describes recent findings on the microbiological, chemical, and molecular aspects of HPP technology used in commercial and research applications. PMID:25629307
Challenging Oil Bioremediation at Deep-Sea Hydrostatic Pressure
Scoma, Alberto; Yakimov, Michail M.; Boon, Nico
2016-01-01
The Deepwater Horizon accident has brought oil contamination of deep-sea environments to worldwide attention. The risk for new deep-sea spills is not expected to decrease in the future, as political pressure mounts to access deep-water fossil reserves, and poorly tested technologies are used to access oil. This also applies to the response to oil-contamination events, with bioremediation the only (bio)technology presently available to combat deep-sea spills. Many questions about the fate of petroleum-hydrocarbons within deep-sea environments remain unanswered, as well as the main constraints limiting bioremediation under increased hydrostatic pressures and low temperatures. The microbial pathways fueling oil bioassimilation are unclear, and the mild upregulation observed for beta-oxidation-related genes in both water and sediments contrasts with the high amount of alkanes present in the spilled oil. The fate of solid alkanes (tar), hydrocarbon degradation rates and the reason why the most predominant hydrocarbonoclastic genera were not enriched at deep-sea despite being present at hydrocarbon seeps at the Gulf of Mexico have been largely overlooked. This mini-review aims at highlighting the missing information in the field, proposing a holistic approach where in situ and ex situ studies are integrated to reveal the principal mechanisms accounting for deep-sea oil bioremediation. PMID:27536290
Raman study of radiation-damaged zircon under hydrostatic compression
Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás
2008-12-01
Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ν3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.
The Research Status and Progress of Heavy/Large Hydrostatic Thrust Bearing
Xibing Li; Xun Wang; Ming Li; Yunshi Ma; Ying Huang
2014-01-01
How to improve the rotation speed of heavy/large CNC vertical lathe, the machining efficiency, and machining precision is one of the key issues which need to be solved urgently. Hydrostatic thrust bearing is the key part to the heavy/large CNC vertical lathe; its performance directly affects the machining quality and operation efficiency. This paper analyses the latest research results from the perspective of the mechanical properties of hydrostatic thrust bearing, oil film lubrication, stati...
Application of hydrostatic leveling system in key scientific engineering and its developing tendency
International Nuclear Information System (INIS)
This paper summarizes the basic principle of the hydrostatic leveling system and technologies used in the worldwide. It emphasizes on the introduction of the international application and development of HLS used in key scientific engineering, especially in electronic accelerators, and the researching background of the new type of HLS for BEPC II. By the introduction, the author also hopes to unify the English name of the hydrostatic leveling system in China, with an aim to be identical with the name internationally used. (authors)
Efficiency of the Ultrasound Guided Hydrostatic Reduction of Intussusception with Normal Saline
Azim Motamed Far; Hamid Dehdashti; Mohammad Davoudi
2010-01-01
Background/Objective: Conventional hydrostatic barium reduction or pneumatic reduction of intussusception is associated with considerable ionizing radiation. The aim of this study was to evaluate ultrasound guided hydrostatic reduction of childhood intussusceptions using water enema."nPatients and Methods: The reduction was attempted using a warm water reservoir at a height of 80-120 cm above the table. The vital signs and the abrupt accumulation of liquid in the abdomen were controlled ...
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The performance of automatic speech recognizer degrades seriously when there are mismatches between the training and testing conditions. Vector Taylor Series (VTS) approach has been used to compensate mismatches caused by additive noise and convolutive channel distortion in the cepstral domain. In this paper, the conventional VTS is extended by incorporating noise clustering into its EM iteration procedure, improving its compensation effectiveness under non-stationary noisy environments. Recognition experiments under babble and exhibition noisy environments demonstrate that the new algorithm achieves35 % average error rate reduction compared with the conventional VTS.
Experimental research on dynamic mechanical properties of PZT ceramic under hydrostatic pressure
International Nuclear Information System (INIS)
Highlights: → We developed an experimental device to examine dynamic mechanical properties of PZT. → Ductile behavior of PZT was seen when hydrostatic pressure was involved. → Compressive strength was shown sensitive to hydrostatic pressure and strain-rate. → A failure criterion was suggested to explain the failure behavior of PZT. - Abstract: An experimental technique for initially applied hydrostatic pressure in specimens subjected to axial impact has been developed to study the dynamic mechanical properties of materials. The technique was employed for the purpose of examining the dynamic mechanical properties of lead zirconate titanate (PZT) at zero to 15 MPa hydrostatic pressures. Experimental results unambiguously exhibit the ductile behavior of PZT when hydrostatic pressure is involved. The compressive strength is demonstrated sensitive to the initial hydrostatic pressure and the strain-rate. The fracture modes are analyzed by means of scanning electron microscopy (SEM). Moreover, a failure criterion based on Mohr-Coulomb failure theory is suggested to explain the brittle and ductile failure of PZT.
Hydraulic efficiency of a hydrostatic transmission with a variable displacement pump and motor
Coombs, Daniel
Pumps and motors are commonly connected hydraulically to create hydrostatic drives, also known as hydrostatic transmissions. A typical hydrostatic transmission consists of a variable displacement pump and a fixed displacement motor. Maximum efficiency is typically created for the system when the motor operates at maximum volumetric displacement. The objective of this research is to determine if a hydrostatic transmission with a variable displacement motor can be more efficient than one with a fixed displacement motor. A work cycle for a Caterpillar 320D excavator was created and the efficiency of the hydrostatic drive system, controlling the swing circuit, with a fixed displacement motor was compared to the efficiency with a variable displacement motor. Both multiplicative and additive uncertainty analysis were performed to determine uncertainty models that could be used to analyze the robustness of the system with feedback control applied. A PID and an H∞ controller were designed for a position control model, as well as velocity control. It was found that while it may seem obvious to achieve maximum efficiency at maximum displacement, there are some cases where maximum efficiency is achieved at a lower displacement. It was also found that for the given work cycle, a hydrostatic transmission with a variable displacement motor can be more efficient.
International Nuclear Information System (INIS)
The ESRF HLS (European Synchrotron Radiation Facility Hydrostatic Leveling system) are based on a water equipotential surface common to all measuring points. The ESRF instruments are composed of three parts. The captor vessel which holds the liquid, a capacitive sensor measuring the capacitance between the water surface and the electrode and a temperature sensor used to correct the dilation of water as a function of temperature between the different vessels in the system. The so-called first generation HLS was conceived and installed to fulfill three main objectives. The first, to minimize the number of leveling surveys by providing a reliable real time height difference measure over several months time period, has not been particularly successful. The second, to control the vertical movements made by the Steinsvik Maskinindustrie jacks during the machine realignment has been very successful. The HLS is regularly employed at the ESRF permitting the real time control of the machine realignment with beam in the machine. This provides a considerable savings in time at the startup for the machine as all pertinent parameters can be followed and corrected on line. Finally following machine and ground motion events in real time is generally reliable over short time spans typically in the order of 24 hours to two weeks. The second generation HLS presently installed on the Storage Ring tunnel roof on the other hand has unequivocally proved to be a reliable system. It demonstrates the usefulness of such a system when it is operating correctly. (Y. Tanaka)
R-peaks detection based on stationary wavelet transform.
Merah, M; Abdelmalik, T A; Larbi, B H
2015-10-01
Automatic detection of the QRS complexes/R-peaks in an electrocardiogram (ECG) signal is the most important step preceding any kind of ECG processing and analysis. The performance of these systems heavily relies on the accuracy of the QRS detector. The objective of present work is to drive a new robust method based on stationary wavelet transform (SWT) for R-peaks detection. The decimation of the coefficients at each level of the transformation algorithm is omitted, more samples in the coefficient sequences are available and hence a better outlier detection can be performed. Using the information of local maxima, minima and zero crossings of the fourth SWT coefficient detail, the proposed algorithm identifies the significant points for detection and delineation of the QRS complexes, as well as detection and identification of the QRS individual waves peaks of the pre-processed ECG signal. Various experimental results show that the proposed algorithm exhibits reliable QRS detection as well as accurate ECG delineation, achieving excellent performance on different databases, on the MIT-BIH database (Se=99.84%, P=99.88%), on the QT Database (Se=99.94%, P=99.89%) and on MIT-BIH Noise Stress Test Database, (Se=95.30%, P=93.98%). Reliability and accuracy are close to the highest among the ones obtained in other studies. Experiments results being satisfactory, the SWT may represent a novel QRS detection tool, for a robust ECG signal analysis. PMID:26105724
Classification of Histological Images Based on the Stationary Wavelet Transform
International Nuclear Information System (INIS)
Non-Hodgkin lymphomas are of many distinct types, and different classification systems make it difficult to diagnose them correctly. Many of these systems classify lymphomas only based on what they look like under a microscope. In 2008 the World Health Organisation (WHO) introduced the most recent system, which also considers the chromosome features of the lymphoma cells and the presence of certain proteins on their surface. The WHO system is the one that we apply in this work. Herewith we present an automatic method to classify histological images of three types of non-Hodgkin lymphoma. Our method is based on the Stationary Wavelet Transform (SWT), and it consists of three steps: 1) extracting sub-bands from the histological image through SWT, 2) applying Analysis of Variance (ANOVA) to clean noise and select the most relevant information, 3) classifying it by the Support Vector Machine (SVM) algorithm. The kernel types Linear, RBF and Polynomial were evaluated with our method applied to 210 images of lymphoma from the National Institute on Aging. We concluded that the following combination led to the most relevant results: detail sub-band, ANOVA and SVM with Linear and RBF kernels
DEFF Research Database (Denmark)
Automatic Program Development is a tribute to Robert Paige (1947-1999), our accomplished and respected colleague, and moreover our good friend, whose untimely passing was a loss to our academic and research community. We have collected the revised, updated versions of the papers published in his...... honor in the Higher-Order and Symbolic Computation Journal in the years 2003 and 2005. Among them there are two papers by Bob: (i) a retrospective view of his research lines, and (ii) a proposal for future studies in the area of the automatic program derivation. The book also includes some papers by...... members of the IFIP Working Group 2.1 of which Bob was an active member. All papers are related to some of the research interests of Bob and, in particular, to the transformational development of programs and their algorithmic derivation from formal specifications. Automatic Program Development offers a...
Energy Technology Data Exchange (ETDEWEB)
Smith, Colin Boughton [Energy Metering Technology (United Kingdom)
2000-08-01
At present, energy audits represent only snapshot situations of the flow of energy. The normal pattern of energy audits as seen through the eyes of an experienced energy auditor is described. A brief history of energy auditing is given. It is claimed that the future of energy auditing lies in automatic meter reading with expert data analysis providing continuous automatic auditing thereby reducing the skill element. Ultimately, it will be feasible to carry out auditing at intervals of say 30 minutes rather than five years.
DEFF Research Database (Denmark)
Burelli, Paolo; Preuss, Mike
2014-01-01
Automatically generating computer animations is a challenging and complex problem with applications in games and film production. In this paper, we investigate howto translate a shot list for a virtual scene into a series of virtual camera configurations — i.e automatically controlling the virtual...... camera. We approach this problem by modelling it as a dynamic multi-objective optimisation problem and show how this metaphor allows a much richer expressiveness than a classical single objective approach. Finally, we showcase the application of a multi-objective evolutionary algorithm to generate a shot...
Torres Moreno, Juan Manuel
2014-01-01
This new textbook examines the motivations and the different algorithms for automatic document summarization (ADS). We performed a recent state of the art. The book shows the main problems of ADS, difficulties and the solutions provided by the community. It presents recent advances in ADS, as well as current applications and trends. The approaches are statistical, linguistic and symbolic. Several exemples are included in order to clarify the theoretical concepts. The books currently available in the area of Automatic Document Summarization are not recent. Powerful algorithms have been develop
Stability of stationary and periodic solutions equations in Banach space
Directory of Open Access Journals (Sweden)
A. Ya. Dorogovtsev
1997-01-01
Full Text Available Linear difference and differential equations with operator coefficients and random stationary (periodic input are considered. Conditions are presented for the mean stability of stationary (periodic solutions under small perturbation of the coefficients.
Universal portfolios generated by weakly stationary processes
Tan, Choon Peng; Pang, Sook Theng
2014-12-01
Recently, a universal portfolio generated by a set of independent Brownian motions where a finite number of past stock prices are weighted by the moments of the multivariate normal distribution is introduced and studied. The multivariate normal moments as polynomials in time consequently lead to a constant rebalanced portfolio depending on the drift coefficients of the Brownian motions. For a weakly stationary process, a different type of universal portfolio is proposed where the weights on the stock prices depend only on the time differences of the stock prices. An empirical study is conducted on the returns achieved by the universal portfolios generated by the Ornstein-Uhlenbeck process on selected stock-price data sets. Promising results are demonstrated for increasing the wealth of the investor by using the weakly-stationary-process-generated universal portfolios.
Stationary processes with pure point diffraction
Lenz, Daniel
2011-01-01
We consider the construction and classification of some new mathematical objects, called ergodic spatial stationary processes, on locally compact Abelian groups, which provide a natural and very general setting for studying diffraction and the famous inverse problems associated with it. In particular we can construct complete families of solutions to the inverse problem from any given pure point measure that is chosen to be the diffraction. In this case these processes can be classified by the dual of the group of relators based on the set of Bragg peaks, and this gives a solution to the homometry problem for pure point diffraction. An ergodic spatial stationary process consists of a measure theoretical dynamical system and a mapping linking it with the ambient space in which diffracting density is supposed to exist. After introducing these processes we study their general properties and link pure point diffraction to almost periodicity. Given a pure point measure we show how to construct from it and a given ...
The stationary Maxwell-Dirac equations
International Nuclear Information System (INIS)
The Maxwell-Dirac equations are the equations for electronic matter, the 'classical' theory underlying QED. The system combines the Dirac equations with the Maxwell equations sourced by the Dirac current. A stationary Maxwell-Dirac system has ψ = e-iEtφ, with φ independent of t. The system is said to be isolated if the dependent variables obey quite weak regularity and decay conditions. In this paper, we prove the following strong localization result for isolated, stationary Maxwell-Dirac systems, - there are no embedded eigenvalues in the essential spectrum, i.e. -m ≤ E ≤ m; - if vertical bar E vertical bar < m then the Dirac field decays exponentially as vertical bar x vertical bar → ∞; - if vertical bar E vertical bar = m then the system is 'asymptotically' static and decays exponentially if the total charge is non-zero
Relativistic elasticity of stationary fluid branes
Armas, Jay; Obers, Niels A.
2013-02-01
Fluid mechanics can be formulated on dynamical surfaces of arbitrary codimension embedded in a background space-time. This has been the main object of study of the blackfold approach in which the emphasis has primarily been on stationary fluid configurations. Motivated by this approach we show under certain conditions that a given stationary fluid configuration living on a dynamical surface of vanishing thickness and satisfying locally the first law of thermodynamics will behave like an elastic brane when the surface is subject to small deformations. These results, which are independent of the number of space-time dimensions and of the fluid arising from a gravitational dual, reveal the (electro)elastic character of (charged) black branes when considering extrinsic perturbations.
Relativistic Elasticity of Stationary Fluid Branes
Armas, Jay
2012-01-01
Fluid mechanics can be formulated on dynamical surfaces of arbitrary co-dimension embedded in a background space-time. This has been the main object of study of the blackfold approach in which the emphasis has primarily been on stationary fluid configurations. Motivated by this approach we show under certain conditions that a given stationary fluid configuration living on a dynamical surface of vanishing thickness and satisfying locally the first law of thermodynamics will behave like an elastic brane when the surface is subject to small deformations. These results, which are independent of the number of space-time dimensions and of the fluid arising from a gravitational dual, reveal the (electro)elastic character of (charged) black branes when considering extrinsic perturbations.
Real Indeterminacy of Stationary Monetary Equilibria in Centralized Economies
Kamiya, Kazuya; Kubota, So; Nakajima, Kayuna
2011-01-01
In this paper, we present a new logic of indeterminacy of stationary monetary equilibria. We rst show that, in a class of dynamic Walrasian market models with at money, stationary equilibria are indeterminate; that is, there exists a continuum of stationary equilibria, where the value of money varies across the stationary equilibria. Then we explore the logic of the indeterminacy, and show that it can be applied not only to dynamic Walrasian market models but also to Jean et al. (2010)'s sear...
Stationary nonlinear Alfven waves and solitons
Hada, T.; Kennel, C. F.; Buti, B.
1989-01-01
Stationary solutions of the derivative nonlinear Schroedinger equation are discussed and classified by using a pseudopotential formulation. The solutions consist of a rich family of nonlinear Alfven waves and solitons with parallel and oblique propagation directions. Expressions for the envelope and the phase of nonlinear waves with periodic envelope modulation, and 'hyperbolic' and 'algebraic' solitons are given. The propagation angle for the slightly modulated elliptic, periodic waves and for oblique solitons is evaluated.
Stationary plume induced by carbon dioxide dissolution
International Nuclear Information System (INIS)
In this paper, laminar convection flows induced by carbon dioxide absorption are addressed from experimental, numerical and theoretical points of view. A vertical glass tube (of centimetre scale) filled with distilled water is subjected to a sudden increase in the partial pressure of carbon dioxide. As a result of the diffusion of the gas into the unsaturated solution, a thin layer of fluid located underneath the surface becomes heavier. This initial density gradient first destabilizes to form a plume, which goes downwards through the entire cell. After a first transient pulsating regime (periodic succession of such Rayleigh-Benard plumes), a stationary flow settles in the tube, which is maintained by the constant supply of gas at the surface. At late stages, this stationary regime is followed by an aperiodic regime, which lasts until the complete saturation of the solution (thermodynamic equilibrium). The present study only focuses on the stationary regime, whose characteristics appear to be almost independent of the Bond number and the aspect ratio but strongly dependent on the chemical Rayleigh number. Three decades of Rayleigh numbers are explored using particle image velocimetry measurements, which allows for a precise determination of the scaling exponents for the vertical velocity amplitude and the plume width. The assumption that gravity and a constant pressure gradient balance the viscous effects enables us to derive an analytic expression for the stationary vertical velocity on the axis, which scales as Ra2/3 (ln Ra)1/3. As a consequence, the width of the plume scales as Ra-1/6 (ln Ra)-1/3 and the mass Nusselt number as (Ra= ln Ra)1/3. These scalings are in excellent agreement with the experimental and numerical results. The multiplicative constants of these scalings can also be calculated and show a fairly good agreement if a rigid boundary condition (no-slip) is assumed at the free surface. (authors)
Stationary phase in the yeast Saccharomyces cerevisiae.
Werner-Washburne, M; Braun, E.; Johnston, G C; Singer, R A
1993-01-01
Growth and proliferation of microorganisms such as the yeast Saccharomyces cerevisiae are controlled in part by the availability of nutrients. When proliferating yeast cells exhaust available nutrients, they enter a stationary phase characterized by cell cycle arrest and specific physiological, biochemical, and morphological changes. These changes include thickening of the cell wall, accumulation of reserve carbohydrates, and acquisition of thermotolerance. Recent characterization of mutant c...
BISTATIC SONOBUOY DEPLOYMENT CONFIGURATION FOR STATIONARY TARGETS
KARATAŞ, Mümtaz; Gülşen AKMAN
2015-01-01
Countering submerged targets using bistatic and multistatic sonobuoy systems is a fundamental problem in Anti-Submarine Warfare. A key question is: what is the best deployment geometry of sensors to successfully detect a submarine threat in a field of interest? The unique properties of these systems distinguish this problem from the conventional ones. This paper examines the optimum deployment strategies of bistatic sonobuoys against stationary or low speed targets.
L1-stability of stationary discrete shocks
International Nuclear Information System (INIS)
The nonlinear stability in the Lp-norm, p ≥ 1, of stationary weak discrete shocks for the Lax-Friedrichs scheme approximating general m x m systems of nonlinear hyperbolic conservation laws is proved, provided that the summations of the initial perturbations equal zero. The result is proved by using a both weighted estimate and characteristic energy method based on the internal structures of the discrete shocks and the essential monotonicity of the Lax-Friedrichs scheme. 13 refs
Direct Georeferencing of Stationary LiDAR
Directory of Open Access Journals (Sweden)
Ahmed Mohamed
2009-12-01
Full Text Available Unlike mobile survey systems, stationary survey systems are given very little direct georeferencing attention. Direct Georeferencing is currently being used in several mobile applications, especially in terrestrial and airborne LiDAR systems. Georeferencing of stationary terrestrial LiDAR scanning data, however, is currently performed indirectly through using control points in the scanning site. The indirect georeferencing procedure is often troublesome; the availability of control stations within the scanning range is not always possible. Also, field procedure can be laborious and involve extra equipment and target setups. In addition, the conventional method allows for possible human error due to target information bookkeeping. Additionally, the accuracy of this procedure varies according to the quality of the control used. By adding a dual GPS antenna apparatus to the scanner setup, thereby supplanting the use of multiple ground control points scattered throughout the scanning site, we mitigate not only the problems associated with indirect georeferencing but also induce a more efficient set up procedure while maintaining sufficient precision. In this paper, we describe a new method for determining the 3D absolute orientation of LiDAR point cloud using GPS measurements from two antennae firmly mounted on the optical head of a stationary LiDAR system. In this paper, the general case is derived where the orientation angles are not small; this case completes the theory of stationary LiDAR direct georeferencing. Simulation and real world field experimentation of the prototype implementation suggest a precision of about 0.05 degrees (~1 milli-radian for the three orientation angles.
Relativistic elasticity of stationary fluid branes
DEFF Research Database (Denmark)
Armas, J.; Obers, N.A.
2013-01-01
under certain conditions that a given stationary fluid configuration living on a dynamical surface of vanishing thickness and satisfying locally the first law of thermodynamics will behave like an elastic brane when the surface is subject to small deformations. These results, which are independent of...... the number of space-time dimensions and of the fluid arising from a gravitational dual, reveal the (electro)elastic character of (charged) black branes when considering extrinsic perturbations. © 2013 American Physical Society....
Stationary Scalar Clouds Around Rotating Black Holes
Hod, Shahar
2012-01-01
Motivated by novel results in the theory of wave dynamics in black-hole spacetimes, we analyze the dynamics of a massive scalar field surrounding a rapidly rotating Kerr black hole. In particular, we report on the existence of stationary (infinitely long-lived) regular field configurations in the background of maximally rotating black holes. The effective height of these scalar "clouds" above the central black hole is determined analytically. Our results support the possible existence of stat...
Gravitating Stationary Dyons and Rotating Vortex Rings
Kleihaus, B; Neemann, U; Kleihaus, Burkhard; Kunz, Jutta; Neemann, Ulrike
2005-01-01
We construct dyons, and electrically charged monopole-antimonopole pairs and vortex rings in Yang-Mills-Higgs theory coupled to Einstein gravity. The solutions are stationary, axially symmetric and asymptotically flat. The dyons with magnetic charge $n\\ge 2$ represent non-static solutions with vanishing angular momentum. The electrically charged monopole-antimonopole pairs and vortex rings, in contrast, possess vanishing magnetic charge, but finite angular momentum, equaling $n$ times their electric charge.
Height Fluctuations for the Stationary KPZ Equation
Borodin, Alexei; Corwin, Ivan; Ferrari, Patrik; Vető, Bálint
2015-12-01
We compute the one-point probability distribution for the stationary KPZ equation (i.e. initial data , for B( X) a two-sided standard Brownian motion) and show that as time T goes to infinity, the fluctuations of the height function grow like T 1/3 and converge to those previously encountered in the study of the stationary totally asymmetric simple exclusion process, polynuclear growth model and last passage percolation. The starting point for this work is our derivation of a Fredholm determinant formula for Macdonald processes which degenerates to a corresponding formula for Whittaker processes. We relate this to a polymer model which mixes the semi-discrete and log-gamma random polymers. A special case of this model has a limit to the KPZ equation with initial data given by a two-sided Brownian motion with drift ß to the left of the origin and b to the right of the origin. The Fredholm determinant has a limit for ß > b, and the case where ß = b (corresponding to the stationary initial data) follows from an analytic continuation argument.
30 CFR 75.1723 - Stationary grinding machines; protective devices.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other...
30 CFR 57.9311 - Anchoring stationary sizing devices.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing...
30 CFR 56.9311 - Anchoring stationary sizing devices.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing...
30 CFR 57.4561 - Stationary diesel equipment underground.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary diesel equipment underground. 57... Fire Prevention and Control Installation/construction/maintenance § 57.4561 Stationary diesel equipment underground. Stationary diesel equipment underground shall be— (a) Supported on a noncombustible base; and...
30 CFR 77.401 - Stationary grinding machines; protective devices.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines; protective... OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped...
30 CFR 57.14115 - Stationary grinding machines.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...
International Nuclear Information System (INIS)
Highlights: •Stress distributions of pits under different hydrostatic pressures are simulated. •Corrosion model of Ni–Cr–Mo–V steel under hydrostatic pressure is established. •A novel understanding of the effect of hydrostatic pressure is proposed. -- Abstract: Corrosion of Ni–Cr–Mo–V high strength steel at different hydrostatic pressures is investigated by scanning electron microscopy (SEM) and finite element analysis (FEA). The results indicate that corrosion pits of Ni–Cr–Mo–V high strength steel originate from inclusions in the steel and high hydrostatic pressures accelerate pit growth rate parallel to steel and the coalescence rate of neighbouring pits, which lead to the fast formation of uniform corrosion. Corrosion of Ni–Cr–Mo–V high strength steel under high hydrostatic pressure is the interaction result between electrochemical corrosion and elastic stress
Automatic Dance Lesson Generation
Yang, Yang; Leung, H.; Yue, Lihua; Deng, LiQun
2012-01-01
In this paper, an automatic lesson generation system is presented which is suitable in a learning-by-mimicking scenario where the learning objects can be represented as multiattribute time series data. The dance is used as an example in this paper to illustrate the idea. Given a dance motion sequence as the input, the proposed lesson generation…
DEFF Research Database (Denmark)
Rosendahl, Mads
1989-01-01
One way to analyse programs is to to derive expressions for their computational behaviour. A time bound function (or worst-case complexity) gives an upper bound for the computation time as a function of the size of input. We describe a system to derive such time bounds automatically using abstract...
International Nuclear Information System (INIS)
Comparative studies in thickening of castings under hydrostatic working (HSW) and on hydrostatic pressing of corundozirconium powders, sintering of semifinished item, depending on HSW pressure were conducted. Some properties of obtained ceramics were analyzed. It was established that sintering of castings, produced by water slip casting with successive HSW, was sufficiently higher, as compared to semifinished item, produced by hydrostatic pressing of powders at the same prssure. This is related with the presence of nonpolymerized colloid components in castings
Hydrostatic pressure effects on the state density and optical transitions in quantum dots
International Nuclear Information System (INIS)
Using the effective mass approximation and variational method we have computed the effects of hydrostatic pressure on the absorption and photoluminescence spectra in spherical quantum dot GaAs-(Ga, Al) As, considering a finite confinement potential of this particular work we show the optical transitions in quantum of various sizes in the presence of hydrogenic impurities and hydrostatic pressure effects. Our first result describes the spectrum of optical absorption of 500 A QD for different values of hydrostatic pressure P = 0, 20 and 40 Kbar. The absorption peaks are sensitive to the displacement of the impurity center to the edge of the quantum dot and even more when the hydrostatic pressure changes in both cases showing that to the extent that these two effects are stronger quantum dots respond more efficiently. Also this result can be seen in the study of the photoluminescence spectrum as in the case of acceptor impurities consider them more efficiently capture carriers or electrons that pass from the conduction band to the valence band. Density states with randomly distributed impurity show that the additional peaks in the curves of the density of impurity states appear due to the presence of the additional hydrostatic pressure effects.
Structure and properties of nano-sized Eurofer 97 steel obtained by hydrostatic extrusion
International Nuclear Information System (INIS)
Full text of publication follows: Properties of engineering materials strongly depend on their microstructure. This in particular applies to the size of grains and/or particles in metals, which influence such properties as hardness, flow stress, toughness and creep. Recently, a large interest has been attracted to the so called nano-materials, characterized by the size of grains/particles below 100 nm. Such nano-scaled structures can be obtained in metals by methods of severe plastic deformation, SPD. Among these methods, hydrostatic extrusion offers the potential for producing homogeneous, fully-dense bulk materials in a variety of forms. Hydrostatic extrusion permits also processing of hard-deformable metals (hydrostatic pressure inhibits crack formation) and consolidation of powders. The objective of the present work was to apply hydrostatic extrusion to Eurofer 97 steel - a fusion relevant material. Samples were hydro-statically extruded in a multi-step process with the total true strain of about 4. Microstructure observations via light and transmission electron microscopy revealed significant grain size refinement and changes in carbides size and distribution. This resulted in substantial changes in mechanical properties of the material which were evaluated by hardness measurements, tensile and impact tests. Thermal stability of these properties was also determined. The results are discussed in terms of microstructure properties relationship. Application potential of nano-Eurofer 97 is also discussed. (authors)
Use of pressurized eccentric tubes to study the effect of hydrostatic stress on swelling
International Nuclear Information System (INIS)
A technique for measuring the effect of hydrostatic stress on radiation-induced swelling is presented. This technique is based on the nonuniform hydrostatic stress that arises when an eccentric tube (a tube with inner and outer surfaces having dissimilar centers of revolution) is internally pressurized. The elastic analyses of the thin- and thick-walled eccentric tube are given. The elastic stress state is allowed to relax plastically, based on a constitutive law for deformation during neutron irradiation. In this case, the constitutive law contains a linearly stress-dependent deviatoric strain rate and a dilatation rate that is linearly dependent on hydrostatic stress. Emphasis is placed on the specimen design and experimental procedure for in-reactor experiments in which the coefficient relating hydrostatic stress and swelling is sought. It is shown that, for the 316L stainless steel specimens placed in EBR-II, we may expect that any appreciable effect of hydrostatic stress on swelling will be observable through changes in specimen curvature
Institute of Scientific and Technical Information of China (English)
ZHANG Yan-qin; FAN Li-guo; LI Rui; DAI Chun-xi; YU Xiao-dong
2013-01-01
To study the heavy hydrostatic bearing with multiple oil pads,a reasonably simplified model of the pad is put forward,and the mathematical model of the bearing characteristics of the multiple oil pad hydrostatic bearing is built with consideration of variable viscosity.The pressure field in the clearance oil film of the hydrostatic bearing at various velocities is simulated based on the Finite Volume Method (FVM) by using the software of Computational Fluid Dynamics (CFD).Some pressure experiments on the hydrostatic bearing were carried out and the results verified the rationality of the simplified model of the pad and the validity of the numerical simulation.It is concluded that the viscosity has a great influence on the pressure in the heavy hydrostatic beating and cannot be neglected,especially,in cases of high rotating speed.The results of numerical calculations provide the internal flow states inside the bearing,which would help the design of the oil cavity structure of the bearing in engineering practice.
Learning Markov models for stationary system behaviors
DEFF Research Database (Denmark)
Chen, Yingke; Mao, Hua; Jaeger, Manfred;
2012-01-01
Establishing an accurate model for formal verification of an existing hardware or software system is often a manual process that is both time consuming and resource demanding. In order to ease the model construction phase, methods have recently been proposed for automatically learning accurate sy...
Automatic indexing, compiling and classification
International Nuclear Information System (INIS)
A review of the principles of automatic indexing, is followed by a comparison and summing-up of work by the authors and by a Soviet staff from the Moscou INFORM-ELECTRO Institute. The mathematical and linguistic problems of the automatic building of thesaurus and automatic classification are examined
International Nuclear Information System (INIS)
The paper describes the automatic gaussmeter operating according to the principle of nuclear magnetic resonance. There have been discussed the operating principle, the block diagram and operating parameters of the meter. It can be applied to measurements of induction in electromagnets of wide-line radio-spectrometers EPR and NMR and in calibration stands of magnetic induction values. Frequency range of an autodyne oscillator from 0,6 up to 86 MHz for protons is corresponding to the field range from 0.016 up to 2T. Applicaton of other nuclei, such as 7Li and 2D is also foreseen. The induction measurement is carried over automatically, and the NMR signal and value of measured induction are displayed on a monitor screen. (author)
Vamos¸, C˘alin
2013-01-01
Our book introduces a method to evaluate the accuracy of trend estimation algorithms under conditions similar to those encountered in real time series processing. This method is based on Monte Carlo experiments with artificial time series numerically generated by an original algorithm. The second part of the book contains several automatic algorithms for trend estimation and time series partitioning. The source codes of the computer programs implementing these original automatic algorithms are given in the appendix and will be freely available on the web. The book contains clear statement of the conditions and the approximations under which the algorithms work, as well as the proper interpretation of their results. We illustrate the functioning of the analyzed algorithms by processing time series from astrophysics, finance, biophysics, and paleoclimatology. The numerical experiment method extensively used in our book is already in common use in computational and statistical physics.
P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI
2013-01-01
The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time A...
Lígia Maria da Silva Ribeiro; Gabriel de Sousa Torcato David
2007-01-01
To profit from the data collected by the SIGARRA academic IS, a systematic setof graphs and statistics has been added to it and are available on-line. Thisanalytic information can be automatically included in a flexible yearly report foreach program as well as in a synthesis report for the whole school. Somedifficulties in the interpretation of some graphs led to the definition of new keyindicators and the development of a data warehouse across the university whereeffective data consolidation...
Automatic Inductive Programming Tutorial
Aler, Ricardo
2006-01-01
Computers that can program themselves is an old dream of Artificial Intelligence, but only nowadays there is some progress of remark. In relation to Machine Learning, a computer program is the most powerful structure that can be learned, pushing the final goal well beyond neural networks or decision trees. There are currently many separate areas, working independently, related to automatic programming, both deductive and inductive. The first goal of this tutorial is to give to the attendants ...
DEFF Research Database (Denmark)
Mueller Loose, Simone
Consumers' food decisions are to a large extent shaped by automatic processes, which are either internally directed through learned habits and routines or externally influenced by context factors and visual information triggers. Innovative research methods such as eye tracking, choice experiments...... and food diaries allow us to better understand the impact of unconscious processes on consumers' food choices. Simone Mueller Loose will provide an overview of recent research insights into the effects of habit and context on consumers' food choices....
Automatic Differentiation Variational Inference
Kucukelbir, Alp; Tran, Dustin; Ranganath, Rajesh; Gelman, Andrew; Blei, David M.
2016-01-01
Probabilistic modeling is iterative. A scientist posits a simple model, fits it to her data, refines it according to her analysis, and repeats. However, fitting complex models to large data is a bottleneck in this process. Deriving algorithms for new models can be both mathematically and computationally challenging, which makes it difficult to efficiently cycle through the steps. To this end, we develop automatic differentiation variational inference (ADVI). Using our method, the scientist on...
Automaticity or active control
DEFF Research Database (Denmark)
Tudoran, Ana Alina; Olsen, Svein Ottar
This study addresses the quasi-moderating role of habit strength in explaining action loyalty. A model of loyalty behaviour is proposed that extends the traditional satisfaction–intention–action loyalty network. Habit strength is conceptualised as a cognitive construct to refer to the psychologic......, respectively, between intended loyalty and action loyalty. At high levels of habit strength, consumers are more likely to free up cognitive resources and incline the balance from controlled to routine and automatic-like responses....
Automatic digital image registration
Goshtasby, A.; Jain, A. K.; Enslin, W. R.
1982-01-01
This paper introduces a general procedure for automatic registration of two images which may have translational, rotational, and scaling differences. This procedure involves (1) segmentation of the images, (2) isolation of dominant objects from the images, (3) determination of corresponding objects in the two images, and (4) estimation of transformation parameters using the center of gravities of objects as control points. An example is given which uses this technique to register two images which have translational, rotational, and scaling differences.
Institute of Scientific and Technical Information of China (English)
DING Jun; CHANG Yaqing; WANG Zichen; SONG Jian
2007-01-01
The manipulation of the chromosome set for commercially valuable marine animals is important for enhancing aquacultural production. In this study, triploid and tetraploid sea cucumber Apostichopus japonicus were induced by hydrostatic pressure shock, and the conditions of appropriate induction were tested with different starting times, and hydrostatic pressure intensities and durations. The highest rate of triploid induction reached 20% and that of tetraploid was 60%. In consideration of the survival rate and hatch rate, the appropriate treatment for triploid was 55 Mpa of hydrostatic pressure for 5 min at 55 min after fertilization (a.f.), while for tetraploid it was 60 Mpa for 5 min at 61 min a.f. The triploid of the sea cucumber could survive through the pelagic larval stage and attachment stage, and develop like the control group of the experiment. The tetraploid, however, could not survive the attachment stage.
International Nuclear Information System (INIS)
The report examines environmental regulatory issues related to the discharge of hydrostatic test waters generated from the integrity testing of natural gas pipelines. Hydrostatic testing, and proper environmental management of discharged waters is required by DOT regulations. However, disposal of water used to conduct a hydrostatic pipeline test is regulated on a state-by-state basis. State-specific requirements vary widely, ranging from an authorization letter to a complete NPDES permit. In some cases, both federal and state permits must be obtained. Monitoring may be required before and during discharge. While some states have established state-wide discharge limits, the majority of the monitoring requirements are determined on a site-specific basis and can include a variety of parameters. The report is Volume 2 of a 5-volume report series
A two-dimensional depth-integrated non-hydrostatic numerical model for nearshore wave propagation
Lu, Xinhua; Dong, Bingjiang; Mao, Bing; Zhang, Xiaofeng
2015-12-01
In this study, we develop a shallow-water depth-integrated non-hydrostatic numerical model (SNH model) using a hybrid finite-volume and finite-difference method. Numerical discretization is performed using the non-incremental pressure-correction method on a collocated grid. We demonstrate that an extension can easily be made from an existing finite-volume method and collocated-grid based hydrostatic shallow-water equations (SWE) model to a non-hydrostatic model. A series of benchmark tests are used to validate the proposed numerical model. Our results demonstrate that the proposed model is robust and well-balanced, and it captures the wet-dry fronts accurately. A comparison between the SNH and SWE models indicates the importance of considering the wave dispersion effect in simulations when the wave amplitude to water depth ratio is large.
Shi, Xun; Nagai, Daisuke; Lau, Erwin T
2015-01-01
Non-thermal pressure in galaxy clusters leads to underestimation of the mass of galaxy clusters based on hydrostatic equilibrium with thermal gas pressure. This occurs even for dynamically relaxed clusters that are used for calibrating the mass-observable scaling relations. We show that the analytical model for non-thermal pressure developed in Shi & Komatsu 2014 can correct for this so-called `hydrostatic mass bias', if most of the non-thermal pressure comes from bulk and turbulent motions of gas in the intracluster medium. Our correction works for the sample average irrespective of the mass estimation method, or the dynamical state of the clusters. This makes it possible to correct for the bias in the hydrostatic mass estimates from X-ray surface brightness and the Sunyaev-Zel'dovich observations that will be available for clusters in a wide range of redshifts and dynamical states.
DEVELOPMENT OF A HYDROSTATIC JOURNAL BEARING WITH SLIT-STEP COMPENSATION
Energy Technology Data Exchange (ETDEWEB)
Hale, L C; Donaldson, R R; Castro, C; Chung, C A; Hopkins, D J
2006-07-28
This paper describes the mathematical modeling and initial testing of an oil-hydrostatic bearing that derives compensation from both a central radial slit where fluid enters and stepped clearances near each end. Bearings using either a radial slit or stepped clearances for compensation were well studied over forty years ago by Donaldson. These bearings have smooth bores uninterrupted with multiple recesses around the circumference. The present slit-step bearing achieves the best of both types with somewhat higher hydrostatic stiffness than the slit bearing and fluid shear drag lower than the step bearing. This is apparent in TABLE 1, which compares calculated values of initial (i.e., centered) hydrostatic stiffness for each type. The slit-step bearing is one of several types being studied at Lawrence Livermore National Laboratory for possible use on the Precision Optical Grinder and Lathe (POGAL).
Energy Technology Data Exchange (ETDEWEB)
Glover, Alan; Purcell, Jennifer; Rudge, Paul; Hudson, Bob [TransCanada PipeLines Ltd., Toronto (Canada)
2005-07-01
Hydrostatic testing has been an accepted method of verifying the integrity of newly constructed pipelines prior to putting them in-service since the mid 1950s. Since that time many things have changed that have reduced the incidence of hydrostatic test failures both during the strength and leak testing portion. Critical to these changes have been improvements in pipeline design, materials and construction technology. Using these advancements TransCanada developed an Alternative Integrity Validation (AIV) approach that could be used to replace the field hydrostatic test on natural gas pipelines. This process was validated with key stake holders and the regulatory body (Alberta Energy Utilities Board) and experimental approval was given to apply the approach on a recent pipeline project. The paper will describe the background to the approach, the AIV process and its successful application on an onshore pipeline project completed in March 2005. The paper will also describe the current limitations in applying the approach and path forward. (author)
Magi, M.; Freivald, A.; Andersson, I.; Ericsson, U.
1981-01-01
Various hydrostatic power transmission systems for automotive applications with power supply at constant pressure and unrestricted flow and with a Volvo Flygmotor variable displacement motor as the principal unit were investigated. Two most promising concepts were analyzed in detail and their main components optimized for minimum power loss at the EPA Urban Driving Cycle. The best fuel consumption is less than 10 lit. per 100 kM for a 1542 kG vehicle with a hydrostatic motor and a two speed gear box in series (braking power not recovered). Realistic system pressure affects the fuel consumption just slightly, but the package volume/weight drastically. Back pressure increases losses significantly. Special attention was paid to description of the behavior and modeling of the losses of variable displacement hydrostatic machines.
Restrepo, R. L.; Giraldo, E.; Miranda, G. L.; Ospina, W.; Duque, C. A.
2009-12-01
The combined effects of the hydrostatic pressure and in-growth direction applied electric field on the binding energy of hydrogenic shallow-donor impurity states in parallel-coupled-GaAs- Ga1-xAlxAs-quantum-well wires are calculated using a variational procedure within the effective-mass and parabolic-band approximations. Results are obtained for several dimensions of the structure, shallow-donor impurity positions, hydrostatic pressure, and applied electric field. Our results suggest that external inputs such us hydrostatic pressure and in-growth direction electric field are two useful tools in order to modify the binding energy of a donor impurity in parallel-coupled-quantum-well wires.
Energy Technology Data Exchange (ETDEWEB)
Restrepo, R.L.; Giraldo, E.; Miranda, G.L.; Ospina, W. [EIA-Fisica Teorica y Aplicada, Escuela de Ingenieria de Antioquia, AA 7516, Medellin (Colombia); Duque, C.A., E-mail: cduque@fisica.udea.edu.c [Instituto de Fisica, Universidad de Antioquia, AA 1226, Medellin (Colombia)
2009-12-15
The combined effects of the hydrostatic pressure and in-growth direction applied electric field on the binding energy of hydrogenic shallow-donor impurity states in parallel-coupled-GaAs-Ga{sub 1-x}Al{sub x}As-quantum-well wires are calculated using a variational procedure within the effective-mass and parabolic-band approximations. Results are obtained for several dimensions of the structure, shallow-donor impurity positions, hydrostatic pressure, and applied electric field. Our results suggest that external inputs such us hydrostatic pressure and in-growth direction electric field are two useful tools in order to modify the binding energy of a donor impurity in parallel-coupled-quantum-well wires.
International Nuclear Information System (INIS)
The combined effects of the hydrostatic pressure and in-growth direction applied electric field on the binding energy of hydrogenic shallow-donor impurity states in parallel-coupled-GaAs-Ga1-xAlxAs-quantum-well wires are calculated using a variational procedure within the effective-mass and parabolic-band approximations. Results are obtained for several dimensions of the structure, shallow-donor impurity positions, hydrostatic pressure, and applied electric field. Our results suggest that external inputs such us hydrostatic pressure and in-growth direction electric field are two useful tools in order to modify the binding energy of a donor impurity in parallel-coupled-quantum-well wires.
Numerical Methods for Finding Stationary Gravitational Solutions
Dias, Oscar J C; Way, Benson
2015-01-01
The wide applications of higher dimensional gravity and gauge/gravity duality have fuelled the search for new stationary solutions of the Einstein equation (possibly coupled to matter). In this topical review, we explain the mathematical foundations and give a practical guide for the numerical solution of gravitational boundary value problems. We present these methods by way of example: resolving asymptotically flat black rings, singly-spinning lumpy black holes in anti-de Sitter (AdS), and the Gregory-Laflamme zero modes of small rotating black holes in AdS$_5\\times S^5$. We also include several tools and tricks that have been useful throughout the literature.
On D = 4 Stationary Black Holes
International Nuclear Information System (INIS)
We review some recent results concerning non-extremal and extremal stationary, asymptotically flat black hole solutions in extended D = 4 supergravities, and their properties with respect to the global symmetries of the theory. More specifically we refer to the effective three-dimensional description of these solutions and their classification within orbits with respect to the action of the global symmetry group, illustrating, for single-center solutions, the general mathematical relation between the orbits of non-extremal and extremal black holes
Stability estimates in stationary inverse transport
Bal, Guillaume
2008-01-01
We study the stability of the reconstruction of the scattering and absorption coefficients in a stationary linear transport equation from knowledge of the full albedo operator in dimension $n\\geq3$. The albedo operator is defined as the mapping from the incoming boundary conditions to the outgoing transport solution at the boundary of a compact and convex domain. The uniqueness of the reconstruction was proved in [M. Choulli-P. Stefanov, 1996 and 1999] and partial stability estimates were obtained in [J.-N. Wang, 1999] for spatially independent scattering coefficients. We generalize these results and prove an $L^1$-stability estimate for spatially dependent scattering coefficients.
Stationary Black Holes: Uniqueness and Beyond
Directory of Open Access Journals (Sweden)
Heusler Markus
1998-01-01
Full Text Available The spectrum of known black hole solutions to the stationary Einstein equations has increased in an unexpected way during the last decade. In particular, it has turned out that not all black hole equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black hole space-times ceases to exist in self-gravitating non-linear field theories. This text aims to review some of the recent developments and to discuss them in the light of the uniqueness theorem for the Einstein-Maxwell system.
Numerical methods for finding stationary gravitational solutions
Dias, Óscar J. C.; Santos, Jorge E.; Way, Benson
2016-07-01
The wide applications of higher dimensional gravity and gauge/gravity duality have fuelled the search for new stationary solutions of the Einstein equation (possibly coupled to matter). In this topical review, we explain the mathematical foundations and give a practical guide for the numerical solution of gravitational boundary value problems. We present these methods by way of example: resolving asymptotically flat black rings, singly spinning lumpy black holes in anti-de Sitter (AdS), and the Gregory–Laflamme zero modes of small rotating black holes in AdS{}5× {S}5. We also include several tools and tricks that have been useful throughout the literature.
Stationary Black Holes: Uniqueness and Beyond
Directory of Open Access Journals (Sweden)
Piotr T. Chruściel
2012-05-01
Full Text Available The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.
Stationary stochastic processes for scientists and engineers
Lindgren, Georg; Sandsten, Maria
2013-01-01
""This book is designed for a first course in stationary stochastic processes in science and engineering and does a very good job in introducing many concepts and ideas to students in these fields. … the book has probably been tested in the classroom many times, which also manifests itself in its virtual lack of typos. … Another great feature of the book is that it contains a wealth of worked example from many different fields. These help clarify concepts and theorems and I believe students will appreciate them-I certainly did. … The book is well suited for a one-semester course as it contains
Comment on "Conformally flat stationary axisymmetric metrics"
Barnes, A; Senovilla, José MM
2003-01-01
Garcia and Campuzano claim to have found a previously overlooked family of stationary and axisymmetric conformally flat spacetimes, contradicting an old theorem of Collinson. In both these papers it is tacitly assumed that the isometry group is orthogonally transitive. Under the same assumption, we point out here that Collinson's result still holds if one demands the existence of an axis of symmetry on which the axial Killing vector vanishes. On the other hand if the assumption of orthogonal transitivity is dropped, a wider class of metrics is allowed and it is possible to find explicit counterexamples to Collinson's result.
Hydrostatic pressure sensor based on micro-cavities developed by the catastrophic fuse effect
Domingues, M. F.; Paixão, T.; Mesquita, E.; Alberto, N.; Antunes, P.; Varum, H.; André, P. S.
2015-09-01
In this work, an optical fiber hydrostatic pressure sensor based in Fabry-Perot micro-cavities is presented. These micro structures were generated by the recycling of optical fiber previously damaged by the fiber fuse effect, resulting in a cost effective solution when compared with the traditional methods used to produce similar micro-cavities. The developed sensor was tested for pressures ranging from 20.0 to 190.0 cmH2O and a sensitivity of 53.7 +/- 2.6 pm/cmH2O for hydrostatic pressures below to 100 cmH2O was achieved.
Hydrostatic supports for telescopes: the experience of 3.5 NTT with a glance at VTL.
Andreolli, C.; Andreolli, C.
1988-10-01
Today's large telescopes use hydrostatic supports to give their axes of motion the highest precision and stiffness. Since their performance of a hydrostatic bearing depend as much on the pad as on the structures directly concerned, certain designing expedients that are peculiar of large machine tools can be adopted profitably with telescopes as well. This was the case with 3.5 m NTT. It may be assumed correctly that the experience made with 3.5 m NTT, may be extended successfully to telescopes of a larger size.
On the propagation of gravity waves in a hydrostatic, compressible fluid with vertical wind shear
Wiin-Nielsen, A.
2011-01-01
The speed of propagation of the vertical modes of gravity waves is found in a non-rotating hydrostatic and compressible fluid with a vertical variation of mean temperature and wind. The analysis is based on a set of linearized equations, and it is assumed that the basic flow as well as the perturbations are hydrostatic. We are therefore concerned with one of the possible wave-type solutions to the primitive equations as they are being used in studies of the general circulation of the atmosphe...
Nonlinear Control of Wind Turbines with Hydrostatic Transmission Based on Takagi-Sugeno Model
International Nuclear Information System (INIS)
A nonlinear model-based control concept for wind turbines with hydrostatic transmission is proposed. The complete mathematical model of a wind turbine drive train with variable displacement pump and variable displacement motor is presented. The controller design takes into consideration the nonlinearity of the aerodynamic maps and hydrostatic drive train by an convex combination of state space controller with measurable generator speed and hydraulic motor displacement as scheduling parameters. The objectives are the set point control of generator speed and tracking control of the rotor speed to reach the maximum power according to the power curve in the partial-load region
Akbas, H.; Sucu, S.; Minez, S.; Dane, C.; Akankan, O.; Erdogan, I.
2016-06-01
We have studied and computed variationally the impurity energy, impurity energy turning points, and ground state normalized binding energy as functions of the impurity position for shallow impurity in asymmetric quantum wells under hydrostatic pressure. We found that the normalized binding energy significantly depends on the asymmetry of the well, besides depending on the impurity position and hydrostatic pressure. Also, the dependence of the positive normalized binding energy on the pressure can be used to find out the degree of the asymmetry of the well or the impurity position in the well.
Nonlinear Control of Wind Turbines with Hydrostatic Transmission Based on Takagi-Sugeno Model
Schulte, Horst; Georg, Soren
2014-06-01
A nonlinear model-based control concept for wind turbines with hydrostatic transmission is proposed. The complete mathematical model of a wind turbine drive train with variable displacement pump and variable displacement motor is presented. The controller design takes into consideration the nonlinearity of the aerodynamic maps and hydrostatic drive train by an convex combination of state space controller with measurable generator speed and hydraulic motor displacement as scheduling parameters. The objectives are the set point control of generator speed and tracking control of the rotor speed to reach the maximum power according to the power curve in the partial-load region.
Comparison of Grain Refinement in Selected Materials Subjected to Hydrostatic Extrusion
Mizera J.; Maj P.; Adamczyk-Cieslak B.
2013-01-01
The subject of this study was to examine and compare the impact of intense hydrostatic extrusion on grain refinement in three different alloys: duplex stainless steel, commercially used aluminum alloy (6060) and Ag-Cu12 alloy. As a result of the process grain sizes from 370 nm to 90 nm were obtained in aluminum and duplex steel. To analyze the of hydrostatic on mechanical properties tensile tests were also carried out. The highest grain refinement (70 nm) and yield strength increase (over 300...
Eddy current inspection of stationary blade rings
International Nuclear Information System (INIS)
Stationary turbine blade rings in a US power plant have experienced chloride-induced cracking. Failure analysis determined two types of cracking mechanisms: corrosion fatigue cracking confined to the leading edge of the outer shroud; and stress corrosion cracking present all over the blade surface. Fluorescent dye penetrant is typically used to detect and size cracks. However, it requires cleaning the blade rings by sandblasting to obtain reliable inspection results. Sand blasting in turn requires sealing the lower half of the turbine housing to prevent sand from contaminating the rest of the power plant components. Furthermore, both the penetrant examination and the removal of the sand are time consuming and costly. An alternative NDE technique is desirable which requires no pre-cleaning of the blade and a quick go/no-go inspection with the capability of estimating the crack length. This paper presents an innovative eddy current technique which meets the desired objectives by incorporating the use of specially designed contoured scanners equipped with an array of pancake coils. A set of eddy current pancake coils housed in three different scanners is used to manually scan and inspect the convex side of the stationary blade rings. The pancake coils are operated in a transmit/receive mode using two separate eddy current instruments. This paper presents the inspection concept, including scanner and probe designs, and test results from the various stages of multiple blade rings
Feasibility of a stationary micro-SQUID
Berger, Jorge
2016-01-01
The standard operation of a dc SQUID leads to oscillatory electric fields that emit electromagnetic radiation and can change the state of the measured sample. A stationary SQUID could be advantageous when back action on the measured sample has to be avoided. We study a superconducting loop that encloses a magnetic flux, connected to a superconducting and to a normal electrode, when a fixed electric current between the electrodes flows through the loop. The considered circuit does not contain Josephson junctions. We find that in a very broad range of parameters the current flow converges to a stationary regime. The potential difference between the electrodes depends on the magnetic flux, so that measuring this voltage would provide information on the enclosed flux. The influence of thermal noise was estimated. The sizes of the voltage and of the power dissipation could be appropriate for the design of a practical fluxmeter. We found narrow ranges of flux at which the voltage varies sharply with the flux.
Stationary versus non-stationary (13)C-MFA: a comparison using a consistent dataset.
Noack, Stephan; Nöh, Katharina; Moch, Matthias; Oldiges, Marco; Wiechert, Wolfgang
2011-07-10
Besides the well-established (13)C-metabolic flux analysis ((13)C-MFA) which characterizes a cell's fluxome in a metabolic and isotopic stationary state a current area of research is isotopically non-stationary MFA. Non-stationary (13)C-MFA uses short-time isotopic transient data instead of long-time isotopic equilibrium data and thus is capable to resolve fluxes within much shorter labeling experiments. However, a comparison of both methods with data from one single experiment has not been made so far. In order to create a consistent database for directly comparing both methods a (13)C-labeling experiment in a fed-batch cultivation with a Corynebacterium glutamicum lysine producer was carried out. During the experiment the substrate glucose was switched from unlabeled to a specifically labeled glucose mixture which was immediately traced by fast sampling and metabolite quenching. The time course of labeling enrichments in intracellular metabolites until isotopic stationarity was monitored by LC-MS/MS. The resulting dataset was evaluated using the classical as well as the isotopic non-stationary MFA approach. The results show that not only the obtained relative data, i.e. intracellular flux distributions, but also the more informative quantitative fluxome data significantly depend on the combination of the measurements and the underlying modeling approach used for data integration. Taking further criteria on the experimental and computational part into consideration, the current limitations of both methods are demonstrated and possible pitfalls are concluded. PMID:20638432
U. YESILGUL; F. UNGAN; E. KASAPOGLU; Sari, H.; I. SÖKMEN
2011-01-01
Using the effective-mass approximation within a variational scheme, we have calculated the diamagnetic susceptibility and binding energy of a hydrogenic donor in a quantum well under different temperatures and hydrostatic pressure conditions. Our calculation have revealed the dependence of the diamagnetic susceptibility and the impurity binding on temperature and hydrostatic pressure.
Malashenko, V. V.; Belykh, N. V.
2013-03-01
The slip of a single edge dislocation in an elastic field of point defects chaotically distributed over a crystal with allowance for a high hydrostatic pressure has been studied theoretically. The numerical estimations have demonstrated that hydrostatic compression of some metals and alloys increases the dislocation drag force by point defects in them by several tens of percent.
International Nuclear Information System (INIS)
Hydrostatic test for RPV (Reactor Pressure Vessel) is not only a means to inspect the vessels and the associated systems but also an important way to verify the results of mechanical analysis. The loading obtained by measurement is useful for the establishment of loading spectrum. Some discussions on the shop hydrostatic test planning for the RPV of Qinshan NPP (Nuclear Power Plant) performed in Japan are presented. Comparisons between the results of hydrostatic test provided by vendor and those of primary system hydrostatic test conducted at Qinshan Site are also given. Some data obtained at Qinshan Site such as actual loading and technical data of the stud-bolt, are listed. The results of measurement for the flange rotation, important for the sealing characteristics of RPV, are specifically discussed. The authors point out some of the mistakes in the results of the shop hydrostatic test
The effect of hydrostatic pressure on the creep life of a 2.25% Cr1% Mo Steel
International Nuclear Information System (INIS)
The effect of superimposed hydrostatic pressures on the creep life of a 2.25% Cr 1% Mo steel, with a bainitic microstructure, is examined. Creep tests have been carried out at 923K with uniaxial stresses in the range 55 to 80 MPa and superimposed hydrostatic pressures up to 35 MPa. Optical and scanning electron microscopy have been used to evaluate the contribution of the hydrostatic stress to grain boundary cavitation. Increasing the hydrostatic pressure for a given uniaxial stress suppresses cavitation, but little changes the secondary creep rate, thereby excending the creep life. Furthermore, the time to failure depends on both the applied uniaxial stress and the hydrostatic pressure and not simply the principal stress. (orig.)
Static- and Stationary-complete Spacetimes: Algebraic and Causal Structures
Harris, Steven G
2014-01-01
This is intended as an analysis of the global properties of static and stationary spacetimes with complete (timelike) Killing field, with particular attention to quotients by group actions. This is presented in terms of algebraic structures which are fairly simple for the static case and more involved for the stationary case; the most important tool, the fundamental cocycle, is a cohomological class for static spacetimes but of somewhat looser structure in the stationary case. In particular: (1) A new measurement, similar to the spacetime interval in Minkowski space, is devised for detecting whether two points are causally related in a stationary spacetime; this proves very useful for analysis. (2) All stationary spacetimes are categorized by how they behave with respect to the fundamental cocycle; this enables a complete characterization of global causality properties. (3) It is shown how these tools determine whether global hyperbolicity of a stationary spacetime is inherited by its quotients. (4) Examples ...
The application of unattended ground sensors to stationary targets
International Nuclear Information System (INIS)
The unattended sensing of stationary (i.e. non-mobile) targets is important in applications ranging from counter-proliferation to law enforcement. With stationary targets, sources of seismic, acoustic, and electro-magnetic emissions can potentially be used to detect, identify, and locate the target. Stationary targets have considerably different sensing requirements than the traditional mobile-target unattended ground sensor applications. This paper presents the novel features and requirements of a system for sensing stationary targets. In particular, issues associated with long-listen time signal processing for signal detection, and array processing techniques for signal localization are presented. Example data and signal processing outputs from a stationary target will be used to illustrate these issues. The impact on sensor, electronic signal processing, battery subsystem, and communication requirements will also be discussed. The paper will conclude with a detailed comparison between mobile-target and stationary-target unattended ground sensor architectures
Automatic radioactive waste recycling
International Nuclear Information System (INIS)
The production of a plutonium ingot by calcium reduction process at CEA/Valduc generates a residue called 'slag'. This article introduces the recycling unit which is dedicated to the treatment of slags. The aim is to separate and to recycle the plutonium trapped in this bulk on the one hand, and to generate a disposable waste from the slag on the other hand. After a general introduction of the facilities, some elements will be enlightened, particularly the dissolution step, the filtration and the drying equipment. Reflections upon technological constraints will be proposed, and the benefits of a fully automatic recycling unit of nuclear waste will also be stressed. (authors)
Automatic Configuration in NTP
Institute of Scientific and Technical Information of China (English)
Jiang Zongli(蒋宗礼); Xu Binbin
2003-01-01
NTP is nowadays the most widely used distributed network time protocol, which aims at synchronizing the clocks of computers in a network and keeping the accuracy and validation of the time information which is transmitted in the network. Without automatic configuration mechanism, the stability and flexibility of the synchronization network built upon NTP protocol are not satisfying. P2P's resource discovery mechanism is used to look for time sources in a synchronization network, and according to the network environment and node's quality, the synchronization network is constructed dynamically.
Transient and Stationary Simulations for a Quantum Hydrodynamic Model
Institute of Scientific and Technical Information of China (English)
HU Xin; TANG Shao-Qiang
2007-01-01
The transient and stationary characteristics of a one-dimensional quantum hydrodynamic model are comparatively studied for semiconductor charge transport in a resonant tunnelling diode. When the bias is not small, our numerical results show a deviation of the asymptotic transient solutions from the stationary ones. A dynamic instability accounts for such deviation. The stationary quantum hydrodynamic model is therefore unsuitable in general for simulating quantum devices.
Stationary Charged Scalar Clouds around Black Holes in String Theory
Bernard, Canisius
2016-01-01
It was reported that Kerr-Newman black holes can support linear charged scalar field in their exterior regions. This stationary massive charged scalar field can form a bound-state and these bound-states are called stationary scalar clouds. In this paper, we study that Kerr-Sen black holes can also support stationary massive charged scalar clouds by matching the near and far region solutions of the radial part of Klein-Gordon wave equation. We also review stationary scalar clouds within the background of static electrically charged black hole solution in the low energy limit of heterotic string field theory namely the GMGHS black holes.
Directory of Open Access Journals (Sweden)
Isac Karimi
2013-01-01
Full Text Available Objective: This study examines the effects of hydrostatic pressure on in vitro maturation (IVM of oocytes derived from in vitro grown follicles.Materials and Methods: In this experimental study, preantral follicles were isolated from 12-day-old female NMRI mice. Each follicle was cultured individually in Alpha Minimal Essential Medium (α-MEM under mineral oil for 12 days. Then, follicles were induced for IVM and divided into two groups, control and experiment. In the experiment group follicles were subjected to 20 mmHg pressure for 30 minutes and cultured for 24-48 hours. We assessed for viability and IVM of the oocytes. The percentage of apoptosis in cumulus cells was determined by the TUNEL assay. A comparison between groups was made using the student’s t test.Results: The percentage of metaphase II oocytes (MII increased in hydrostatic pressure-treated follicles compared to controls (p<0.05. Cumulus cell viability reduced in hydrostatic pressure-treated follicles compared to controls (p<0.05. Exposure of follicles to pressure increased apoptosis in cumulus cells compared to controls (p<0.05.Conclusion: Hydrostatic pressure, by inducing apoptosis in cumulus cells, participates in the cumulus oocyte coupled relationship with oocyte maturation.
Inactivation of human norovirus in contaminated oysters and clams by high-hydrostatic pressure
Human norovirus (NoV) is the most frequent causative agent of foodborne disease associated with shellfish consumption. In this study, the effect of high-hydrostatic pressure (HHP) on inactivation of NoV was determined. Genogroup I.1 (GI.1) or Genogroup II.4 (GII.4) NoV were inoculated into oyster ho...
Hydrostatic Pressure Project: Linked-Class Problem-Based Learning in Engineering
Davis, Freddie J.; Lockwood-Cooke, Pamela; Hunt, Emily M.
2011-01-01
Over the last few years, WTAMU Mathematics, Engineering and Science faculty has used interdisciplinary projects as the basis for implementation of a linked-class approach to Problem-Based Learning (PBL). A project that has significant relevance to engineering statics, fluid mechanics, and calculus is the Hydrostatic Pressure Project. This project…
Huang, Weifeng; Liao, Chuanjun; Liu, Xiangfeng; Suo, Shuangfu; Liu, Ying; Wang, Yuming
2014-09-01
Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power plants. More accurate models on the operating mechanism of the seals are needed to help improve their performance. The thermal fluid-solid interaction (TFSI) mechanism of the hydrostatic seal is investigated in this study. Numerical models of the flow field and seal assembly are developed. Based on the mechanism for the continuity condition of the physical quantities at the fluid-solid interface, an on-line numerical TFSI model for the hydrostatic mechanical seal is proposed using an iterative coupling method. Dynamic mesh technology is adopted to adapt to the changing boundary shape. Experiments were performed on a test rig using a full-size test seal to obtain the leakage rate as a function of the differential pressure. The effectiveness and accuracy of the TFSI model were verified by comparing the simulation results and experimental data. Using the TFSI model, the behavior of the seal is presented, including mechanical and thermal deformation, and the temperature field. The influences of the rotating speed and differential pressure of the sealing device on the temperature field, which occur widely in the actual use of the seal, are studied. This research proposes an on-line and assembly-based TFSI model for hydrostatic mechanical face seals, and the model is validated by full-sized experiments.
Institute of Scientific and Technical Information of China (English)
HUANG Weifeng; LIAO Chuanjun; LIU Xiangfeng; SUO Shuangfu; LIU Ying; WANG Yuming
2014-01-01
Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power plants. More accurate models on the operating mechanism of the seals are needed to help improve their performance. The thermal fluid-solid interaction (TFSI) mechanism of the hydrostatic seal is investigated in this study. Numerical models of the flow field and seal assembly are developed. Based on the mechanism for the continuity condition of the physical quantities at the fluid-solid interface, an on-line numerical TFSI model for the hydrostatic mechanical seal is proposed using an iterative coupling method. Dynamic mesh technology is adopted to adapt to the changing boundary shape. Experiments were performed on a test rig using a full-size test seal to obtain the leakage rate as a function of the differential pressure. The effectiveness and accuracy of the TFSI model were verified by comparing the simulation results and experimental data. Using the TFSI model, the behavior of the seal is presented, including mechanical and thermal deformation, and the temperature field. The influences of the rotating speed and differential pressure of the sealing device on the temperature field, which occur widely in the actual use of the seal, are studied. This research proposes an on-line and assembly-based TFSI model for hydrostatic mechanical face seals, and the model is validated by full-sized experiments.
Phytophthora nicotianae Breda de Haan was used as a model pathogen to investigate the effects of hydrostatic pressure, agitation, and aeration with CO2 or breathable air on the survival of Phytophthora zoospores in water. Injecting CO2 into 2 liters of zoospore-infested water for 5 min at 110.4 ml ...
Zinoviev, P.A.; Tsvetkov, S.V.; Kulish, G.G.; Berg, van den R.W.; Schepdael, van L.J.M.M.
2001-01-01
Three types of high-strength unidirectional composite materials were studied under longitudinal tension with superposed high hydrostatic pressure. Reinforcing fibers were T1000G carbon, S2 glass and Zylon PBO fibers; the Ciba 5052 epoxy resin was used as matrix. The composites were tested under exte
Ill-Posedness of the Hydrostatic Euler and Singular Vlasov Equations
Han-Kwan, Daniel; Nguyen, Toan T.
2016-09-01
In this paper, we develop an abstract framework to establish ill-posedness, in the sense of Hadamard, for some nonlocal PDEs displaying unbounded unstable spectra. We apply this to prove the ill-posedness for the hydrostatic Euler equations as well as for the kinetic incompressible Euler equations and the Vlasov-Dirac-Benney system.
Pelton, Rick; Espy, John
This third in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I describes the principles and practices associated with hydrostatic testing. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student,…
Model experiments on the hydrostatic bearing of the 80 HGXW pump
International Nuclear Information System (INIS)
A stand simulating the design conditions in an actual sodium pump was built for testing a centrifugal liquid sodium pump with a radial hydrostatic guide bearing. The load capacity was measured on the stand and the experimental values obtained were compared to theoretical calculations. Inertia current effects included in the calculation are small and do not exceed the measurement error. (H.S.)
Mechanical stability of Ni and Ir under hydrostatic and uniaxial loading
Czech Academy of Sciences Publication Activity Database
Řehák, Petr; Černý, Miroslav; Šob, Mojmír
2015-01-01
Roč. 23, č. 5 (2015), art. n. 055010. ISSN 0965-0393 R&D Projects: GA ČR(CZ) GAP108/12/0311 Institutional support: RVO:68081723 Keywords : ab initio calculations * elastic stability * phonon instability * theoretical strength * hydrostatic loading * uniaxial loading Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.167, year: 2014
Hydrostatic compression of galenobismutite (PbBi_{2}S_{4})
DEFF Research Database (Denmark)
Olsen, Lars Arnskov; Balic Zunic, Tonci; Makovicky, Emil;
2007-01-01
A single-crystal sample of galenobismutite was subjected to hydrostatic pressures in the range of 0.0001 and 9 GPa at room temperature using the diamond-anvil cell technique. A series of X-ray diVraction intensities were collected at ten distinct pressures using a CCD equipped 4-circle di...
Roche, Yann; Klymchenko, Andrey S; Gerbeau-Pissot, Patricia; Gervais, Patrick; Mély, Yves; Simon-Plas, Françoise; Perrier-Cornet, Jean-Marie
2010-08-01
We monitored the behavior of plasma membrane (PM) isolated from tobacco cells (BY-2) under hydrostatic pressures up to 3.5kbar at 30 degrees C, by steady-state fluorescence spectroscopy using the newly introduced environment-sensitive probe F2N12S and also Laurdan and di-4-ANEPPDHQ. The consequences of sterol depletion by methyl-beta-cyclodextrin were also studied. We found that application of hydrostatic pressure led to a marked decrease of hydration as probed by F2N12S and to an increase of the generalized polarization excitation (GPex) of Laurdan. We observed that the hydration effect of sterol depletion was maximal between 1 and 1.5 kbar but was much less important at higher pressures (above 2 kbar) where both parameters reached a plateau value. The presence of a highly dehydrated gel state, insensitive to the sterol content, was thus proposed above 2.5 kbar. However, the F2N12S polarity parameter and the di-4-ANEPPDHQ intensity ratio showed strong effect on sterol depletion, even at very high pressures (2.5-3.5 kbar), and supported the ability of sterols to modify the electrostatic properties of membrane, notably its dipole potential, in a highly dehydrated gel phase. We thus suggested that BY-2 PM undergoes a complex phase behavior in response to the hydrostatic pressure and we also emphasized the role of phytosterols to regulate the effects of high hydrostatic pressure on plant PM. PMID:20381451
Israel, Holger; Nevalainen, Jukka; Massey, Richard; Reiprich, Thomas
2014-01-01
The temperature of X-ray emitting gas $T_X$ is often used to infer the total mass of galaxy clusters (under the assumption of hydrostatic equilibrium). Unfortunately, XMM-Newton and Chandra observatories measure inconsistent temperatures for the same gas, due to uncertain instrumental calibration. We translate the relative bias in $T_X$ measurements of Schellenberger et al. (2014) into a bias on inferred mass for a sample of clusters with homogeneous weak lensing (WL) masses, to simultaneously examine the hydrostatic bias and instrument calibration. Israel et al. (2014) found consistent WL and Chandra hydrostatic X-ray masses for a sample of clusters at $z$~0.5 and masses of a few $10^{14}$ $M_{\\odot}$. We find their XMM-Newton masses to be lower by $b^{xcal}=15$-$20$ % than their Chandra masses. At the massive end ($>5\\cdot 10^{14}$ $M_{\\odot}$), the XMM-Newton masses are ~35% lower than the WL masses. Assuming that the true hydrostatic bias is 20 %, as indicated by simulations, our results for the massive e...
Danish emission inventories for stationary combustion plants
DEFF Research Database (Denmark)
Nielsen, M.; Illerup, J. B.
Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are SO2, NOX, NMVOC, CH4, CO, CO2, N2O, particulate matter, heavy metals, dioxins and PAH. Since 1990 the fuel consumption in...... decrease of the SO2, NOX and heavy metal emissions is mainly a result of decreased emissions from large power plants and waste incineration plants. The greenhouse gas emission has decreased 1,3% since 1990. The emission of CH4, however, has increased due to increased use of lean-burn gas engines in CHP...... plants. The emission of PAH increased as a result of the increased combustion of wood in residential boilers and stoves. Uncertainties for the emissions and trends have been estimated...
Danish emission inventories for stationary combustion plants
DEFF Research Database (Denmark)
Nielsen, M.; Illerup, J. B.
Emission inventories for stationary combustion plants are presented and the methodologies and assumptions used for the inventories are described. The pollutants considered are: SO2, NOx, NMVOC, CH4, CO, CO2, N2O, particulate matter, heavy metals, dioxins and PAH. Since 1990 the fuel consumption in...... decrease of the SO2, NOx and heavy metal emissions is mainly a result of decreased emissions from large power plants and waste incineration plants. The greenhouse gas emission has decreased 1,5% since 1990. The emission of CH4, however, has increased due to increased use of lean-burn gas engines in CHP...... plants. The emission of PAH increased as a result of the increased combustion of wood in residential boilers and stoves. Uncertainties for the emissions and trends have been estimated....
Carbon nanotube stationary phases for microchip electrochromatography
DEFF Research Database (Denmark)
Mogensen, Klaus Bo; Bøggild, Peter; Kutter, Jörg Peter
, microfluidic devices with microfabricated carbon nanotube columns for electrochromatographic separations will be presented. The electrically conductive carbon nanotube layer has been patterned into hexoganol micropillars in order to support electroosmotic flow without forming gas bubbles from electrolysis of......The use of nanomaterials in separation science has increased rapidly in the last decade. The reason for this is to take advantage of the unique properties of these materials, such as a very high surface-to-volume ratio and favourable sorbent behaviour. Carbon nanostructures, such as carbon...... nanotubes are very interesting for integration in especially microfluidic devices, because they can readily be grown on planar substrates by means of chemical vapour deposition. In this way the cumbersome process of packing of the stationary phase in the finished microfluidic channels is avoided and the CNT...
Quantum teleportation between stationary macroscopic objects
International Nuclear Information System (INIS)
Quantum teleportation is a process to transfer a quantum state of an object without transferring the state carrier itself. So far, most of the teleportation experiments realized are within the photonic regime. For the teleportation of stationary states, the largest system reported is a single ion. We are now performing an experiment to teleport the state of an macroscopic atomic cloud which consists about 106 single atoms. In our experiment two atomic ensembles are utilized. In the first ensemble A we prepare the collective atomic state to be teleported using the quantum feedback technique. The second ensemble B is utilized to generate entanglement between it collective state with a scattered single-photon. Teleportation is realized by converting the atomic state of A to a single-photon and making a Bell state measurement with the scattered single-photon from ensemble B.
Separable geodesic action slicing in stationary spacetimes
Bini, Donato; Jantzen, Robert T
2014-01-01
A simple observation about the action for geodesics in a stationary spacetime with separable geodesic equations leads to a natural class of slicings of that spacetime whose orthogonal geodesic trajectories represent freely falling observers. The time coordinate function can then be taken to be the observer proper time, leading to a unit lapse function. This explains some of the properties of the original Painlev\\'e-Gullstrand coordinates on the Schwarzschild spacetime and their generalization to the Kerr-Newman family of spacetimes, reproducible also locally for the G\\"odel spacetime. For the static spherically symmetric case the slicing can be chosen to be intrinsically flat with spherically symmetric geodesic observers, leaving all the gravitational field information in the shift vector field.
Effective complexity of stationary process realizations
Ay, Nihat; Szkola, Arleta
2010-01-01
The concept of effective complexity of an object as the minimal description length of its regularities has been initiated by Gell-Mann and Lloyd. Based on their work we gave a precise definition of effective complexity of finite binary strings in terms of algorithmic information theory in our previous paper. Here we study the effective complexity of strings generated by stationary processes. Sufficiently long typical process realizations turn out to be effectively simple under any linear scaling with the string's length of the parameter $\\Delta$ which determines the minimization domain. For a class of computable ergodic processes including i.i.d. and ergodic Markovian processes a stronger result can be shown: There exist sublinear scalings of $\\Delta$ for which typical realizations turn out to be effectively simple. Our results become most transparent in the context of coarse effective complexity --a modification of plain effective complexity, where $\\Delta$ appears as a minimization argument. A similar modif...
Quantum teleportation between stationary macroscopic objects
Energy Technology Data Exchange (ETDEWEB)
Bao, Xiao-Hui; Yuan, Zhen-Sheng; Pan, Jian-Wei [Physikalisches Institut, Universitaet Heidelberg (Germany); Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei (China); Xu, Xiao-Fan [Physikalisches Institut, Universitaet Heidelberg (Germany); Li, Che-Ming [Physikalisches Institut, Universitaet Heidelberg (Germany); Department of Physics, National Center for Theoretical Sciences, National Cheng Kung University, Tainan (China)
2010-07-01
Quantum teleportation is a process to transfer a quantum state of an object without transferring the state carrier itself. So far, most of the teleportation experiments realized are within the photonic regime. For the teleportation of stationary states, the largest system reported is a single ion. We are now performing an experiment to teleport the state of an macroscopic atomic cloud which consists about 10{sup 6} single atoms. In our experiment two atomic ensembles are utilized. In the first ensemble A we prepare the collective atomic state to be teleported using the quantum feedback technique. The second ensemble B is utilized to generate entanglement between it collective state with a scattered single-photon. Teleportation is realized by converting the atomic state of A to a single-photon and making a Bell state measurement with the scattered single-photon from ensemble B.
Complex conjugate pairs in stationary Sturmians
International Nuclear Information System (INIS)
Sturmian expansions enable a simply accurate separable specification of two nucleon t matrices based upon realistic two nucleon interactions. Sturmian eigenstates specified by stationary scattering boundary conditions are particularly useful in that context, and they can be calculated by solving a generalised eigenvalue equation using real and symmetric matrices. In general, the spectrum of such an equation may contain complex eigenvalues. But to each complex eigenvalues there is a corresponding conjugate partner. In studies using realistic two nucleon potentials, and in certain positive energy intervals, these complex conjugated pairs indeed appear in the Sturmian spectrum. However, it is demonstrated that it is possible to recombine the complex conjugate pairs and corresponding states into a new, (and useful) pair of real eigenvalues and eigenstates with which of effect separable expansions of the (real) two nucleon reactance matrices. 8 refs
Complex conjugate pairs in stationary Sturmian eigenstates
International Nuclear Information System (INIS)
Sturmian eigenstates specified by stationary scattering boundary conditions are particularly useful in contexts such as forming simple separable two nucleon t matrices, and are determined via solution of generalized eigenvalue equation using real and symmetric matrices. In general, the spectrum of such an equation may contain complex eigenvalues. But to each complex eigenvalue there is a corresponding conjugate partner. In studies using realistic nucleon-nucleon potentials, and in certain positive energy intervals, these complex conjugated pairs indeed appear in the Sturmian spectrum. However, as we demonstrate herein, it is possible to recombine the complex conjugate pairs and corresponding states into a new, sign-definite pair of real quantities with which to effect separable expansions of the (real) nucleon-nucleon reactance matrices
Complex Conjugate Pairs in Stationary Sturmians
Dortmans, P J; Pisent, G; Amos, K A
1993-01-01
Sturmian eigenstates specified by stationary scattering boundary conditions are particularly useful in contexts such as forming simple separable two nucleon t matrices, and are determined via solution of generalised eigenvalue equation using real and symmetric matrices. In general, the spectrum of such an equation may contain complex eigenvalues. But to each complex eigenvalue there is a corresponding conjugate partner. In studies using realistic nucleon--nucleon potentials, and in certain positive energy intervals, these complex conjugated pairs indeed appear in the Sturmian spectrum. However, as we demonstrate herein, it is possible to recombine the complex conjugate pairs and corresponding states into a new, sign--definite pair of real quantities with which to effect separable expansions of the (real) nucleon--nucleon reactance matrices.
Stationary turbine component with laminated skin
James, Allister W.
2012-08-14
A stationary turbine engine component, such as a turbine vane, includes a internal spar and an external skin. The internal spar is made of a plurality of spar laminates, and the external skin is made of a plurality of skin laminates. The plurality of skin laminates interlockingly engage the plurality of spar laminates such that the external skin is located and held in place. This arrangement allows alternative high temperature materials to be used on turbine engine components in areas where their properties are needed without having to make the entire component out of such material. Thus, the manufacturing difficulties associated with making an entire component of such a material and the attendant high costs are avoided. The skin laminates can be made of advanced generation single crystal superalloys, intermetallics and refractory alloys.
Effective Complexity of Stationary Process Realizations
Directory of Open Access Journals (Sweden)
Arleta Szkoła
2011-06-01
Full Text Available The concept of effective complexity of an object as the minimal description length of its regularities has been initiated by Gell-Mann and Lloyd. The regularities are modeled by means of ensembles, which is the probability distributions on finite binary strings. In our previous paper [1] we propose a definition of effective complexity in precise terms of algorithmic information theory. Here we investigate the effective complexity of binary strings generated by stationary, in general not computable, processes. We show that under not too strong conditions long typical process realizations are effectively simple. Our results become most transparent in the context of coarse effective complexity which is a modification of the original notion of effective complexity that needs less parameters in its definition. A similar modification of the related concept of sophistication has been suggested by Antunes and Fortnow.
Stationary phases for superheated water chromatography
Saha, S
2002-01-01
This project focused on the comparison of conventional liquid chromatography and superheated water chromatography. It examined the differences in efficiency and retention of a range of different stationary phases. Alkyl aryl ketones and eight aromatic compounds were separated on PBD-zirconia, Xterra RP 18, Luna C sub 1 sub 8 (2) and Oasis HLB columns using conventional LC and superheated water chromatography system. The retention indices were determined in the different eluents. On changing the organic component of the eluent from methanol to acetonitrile to superheated water considerable improvements were found in the peak shapes and column efficiencies on the PBD-zirconia and Oasis HLB columns. PS-DVB, PBD-zirconia and Xterra RP 18 columns have been used in efficiency studies. It was found that simply elevating the column temperature did not increase the efficiency of a separation in superheated water chromatography. The efficiency depended on flow rate, injection volume and also mobile phase preheating sys...
Generalized Gibbs Entropy, Irreversibility and Stationary States
Directory of Open Access Journals (Sweden)
A. Pérez-Madrid
2005-12-01
Full Text Available A generalization of the Gibbs entropy postulate is proposed, based on the BBGKY hierarchy as the non-equilibrium entropy for a system of N interacting particles. This entropy satisfies the basic principles of thermodynamics in the sense that it reaches its maximum at equilibrium and is coherent with the second law. By using this entropy and the methods of non-equilibrium thermodynamics in the phase space, a generalization of the Liouville equation describing the evolution of the distribution vector in the form of a master equation is obtained. After neglecting correlations in this master equation, the Boltzmann equation was obtained. Moreover, this entropy remains constant in nonequilibrium stationary states and leads to macroscopic hydrodynamics. Non-equilibrium Green-Kubo type relations and the probability for the non-equilibrium fluctuations are also derived.
Electric propulsion for control of stationary satellites
Energy Technology Data Exchange (ETDEWEB)
Boucher, Roland
1963-03-15
The application of electric propulsion engines to attitude control and stationkeeping of 24-hour stationary satellites is analyzed and compared with the performance of contemporary cold gas, monopropellant, and bipropellant propulsion systems. Both a 500-pound spin-stabilized and a 1500-pound three-axis controlled satellite compatible with current boost vehicles are examined, and each type of propulsion system compared as a function of mission duration and maneuver requirements. Solar electric propulsion is shown to be superior to chemical propulsion for long term stationkeeping and three-axis attitude control of the larger satellite. Cold gas and chemical propulsion are superior for attitude control and provide strong competition for electric propulsion in the stationkeeping of the smaller spin-stabilized satellite. (auth)
Flood frequency analysis of historical flood data under stationary and non-stationary modelling
Directory of Open Access Journals (Sweden)
M. J. Machado
2015-01-01
Full Text Available Historical records are an important source of information about extreme and rare floods with a great value to establish a reliable flood return frequency. The use of long historic records for flood frequency analysis brings in the question of flood stationarity, since climatic and land-use conditions can affect the relevance of past flooding as a predictor of future flooding. In this paper, a detailed 400 year flood record from the Tagus River in Aranjuez (Central Spain was analysed under stationary and non-stationary flood frequency approaches, to assess their implications on hazard studies. Historical flood records in Aranjuez were obtained from documents (Proceedings of the City Council, diaries, chronicles, memoirs, etc., epigraphic marks, and indirect historical sources and reports. The water levels associated with different floods (derived from descriptions or epigraphic marks were computed into discharge values using a one-dimensional hydraulic model. Secular variations on flood magnitude and frequency, found to respond to climate and environmental drivers, showed a good correlation between high values of historical flood discharges and a negative mode of the North Atlantic Oscillation index (NAO index. Over the systematic gauge record (1913–2008, an abrupt change on flood magnitude was produced in 1957 due to constructions of three major reservoirs in the Tagus headwaters (Bolarque, Entrepeñas and Buendia controlling 80% of the watershed surface draining to Aranjuez. Two different models were used for the flood frequency analysis: (a a stationary model estimating statistical distributions incorporating imprecise and categorical data based on maximum likelihood estimators; (b a time–varying model based on "generalized additive models for location, scale and shape" (GAMLSS modelling, that incorporates external covariates related to climate variability (NAO index and catchment hydrology factors (in this paper a reservoir index; RI
Flood frequency analysis of historical flood data under stationary and non-stationary modelling
Machado, M. J.; Botero, B. A.; López, J.; Francés, F.; Díez-Herrero, A.; Benito, G.
2015-06-01
Historical records are an important source of information on extreme and rare floods and fundamental to establish a reliable flood return frequency. The use of long historical records for flood frequency analysis brings in the question of flood stationarity, since climatic and land-use conditions can affect the relevance of past flooding as a predictor of future flooding. In this paper, a detailed 400 yr flood record from the Tagus River in Aranjuez (central Spain) was analysed under stationary and non-stationary flood frequency approaches, to assess their contribution within hazard studies. Historical flood records in Aranjuez were obtained from documents (Proceedings of the City Council, diaries, chronicles, memoirs, etc.), epigraphic marks, and indirect historical sources and reports. The water levels associated with different floods (derived from descriptions or epigraphic marks) were computed into discharge values using a one-dimensional hydraulic model. Secular variations in flood magnitude and frequency, found to respond to climate and environmental drivers, showed a good correlation between high values of historical flood discharges and a negative mode of the North Atlantic Oscillation (NAO) index. Over the systematic gauge record (1913-2008), an abrupt change on flood magnitude was produced in 1957 due to constructions of three major reservoirs in the Tagus headwaters (Bolarque, Entrepeñas and Buendia) controlling 80% of the watershed surface draining to Aranjuez. Two different models were used for the flood frequency analysis: (a) a stationary model estimating statistical distributions incorporating imprecise and categorical data based on maximum likelihood estimators, and (b) a time-varying model based on "generalized additive models for location, scale and shape" (GAMLSS) modelling, which incorporates external covariates related to climate variability (NAO index) and catchment hydrology factors (in this paper a reservoir index; RI). Flood frequency
International Nuclear Information System (INIS)
A measuring system is disclosed for surveying and very accurately positioning objects with respect to a reference line. A principal use of this surveying system is for accurately aligning the electromagnets which direct a particle beam emitted from a particle accelerator. Prior art surveying systems require highly skilled surveyors. Prior art systems include, for example, optical surveying systems which are susceptible to operator reading errors, and celestial navigation-type surveying systems, with their inherent complexities. The present invention provides an automatic readout micrometer which can very accurately measure distances. The invention has a simplicity of operation which practically eliminates the possibilities of operator optical reading error, owning to the elimination of traditional optical alignments for making measurements. The invention has an extendable arm which carries a laser surveying target. The extendable arm can be continuously positioned over its entire length of travel by either a coarse or fine adjustment without having the fine adjustment outrun the coarse adjustment until a reference laser beam is centered on the target as indicated by a digital readout. The length of the micrometer can then be accurately and automatically read by a computer and compared with a standardized set of alignment measurements. Due to its construction, the micrometer eliminates any errors due to temperature changes when the system is operated within a standard operating temperature range
Automatic personnel contamination monitor
International Nuclear Information System (INIS)
United Nuclear Industries, Inc. (UNI) has developed an automatic personnel contamination monitor (APCM), which uniquely combines the design features of both portal and hand and shoe monitors. In addition, this prototype system also has a number of new features, including: micro computer control and readout, nineteen large area gas flow detectors, real-time background compensation, self-checking for system failures, and card reader identification and control. UNI's experience in operating the Hanford N Reactor, located in Richland, Washington, has shown the necessity of automatically monitoring plant personnel for contamination after they have passed through the procedurally controlled radiation zones. This final check ensures that each radiation zone worker has been properly checked before leaving company controlled boundaries. Investigation of the commercially available portal and hand and shoe monitors indicated that they did not have the sensitivity or sophistication required for UNI's application, therefore, a development program was initiated, resulting in the subject monitor. Field testing shows good sensitivity to personnel contamination with the majority of alarms showing contaminants on clothing, face and head areas. In general, the APCM has sensitivity comparable to portal survey instrumentation. The inherit stand-in, walk-on feature of the APCM not only makes it easy to use, but makes it difficult to bypass. (author)
Efficiency of the Ultrasound Guided Hydrostatic Reduction of Intussusception with Normal Saline
Directory of Open Access Journals (Sweden)
Azim Motamed Far
2010-05-01
Full Text Available Background/Objective: Conventional hydrostatic barium reduction or pneumatic reduction of intussusception is associated with considerable ionizing radiation. The aim of this study was to evaluate ultrasound guided hydrostatic reduction of childhood intussusceptions using water enema."nPatients and Methods: The reduction was attempted using a warm water reservoir at a height of 80-120 cm above the table. The vital signs and the abrupt accumulation of liquid in the abdomen were controlled during the procedure. Reduction of intussuscepted loops was controlled by sonography, the observed fluid surrounding the intussusception was gradually reduced through the ileocecal valve. The procedure was continued until the intussusceptum disappeared completely and the distal ileum was filled with water. The reduction was stopped for 10-15 minutes in those patients in whom the procedure failed after a 10-minute effort. Then the procedure was applied for maximum three times and manual abdominal palpation was applied in some patients to ease the reduction. After successful reduction, the abdomen was re-examined to detect any lead point or recurrence of intussusception. The patients were then transferred to the surgery ward and after 24 hours, the regular oral diet was started and the patients were discharged. Partially reduced cases of intussusception underwent surgical treatment. Fisher exact test was used for the assessment of the relation between intussusception sites and the hydrostatic reduction outcome and/or presence of gangrenous bowel."nResults: Complete reduction was achieved in 21 of 24 patients (87.5%. Hydrostatic reduction was impossible in three patients, bowel resection was performed in 2 patients and the intussusceptions were surgically reduced in one patient."nConclusion: Intussusception is the most common abdominal emergency of early childhood for which non-operative reduction is currently the treatment of choice."nKeywords: Intussusception
On the comparison between stationary and non-stationary high temperature tensile creep
International Nuclear Information System (INIS)
In the present paper the conditions for a comparison between stationary and non-stationary tensional creep are examined by means of an equivalent stress sigmasub(e) and equivalent temperature Tsub(e), respectively. These quantities properly take into account the direct influence of stress and temperature on creep for different loading type. For sigmasub(e) and Tsub(e) analytical expressions are derived which contain the parameters characterizing the particular loading type. From the analysis it follows that the virtual difference between creep at different loading types should manifest in the deformation substructure. As examples, saw tooth stress and temperature cycling, trapezoidal stress cycling and linear stress and temperature ramp loading are treated. (orig.)
Fabiano Azevedo DORÇA; Luciano Vieira LIMA; Márcia Aparecida FERNANDES; Carlos Roberto LOPES
2012-01-01
Considering learning and how to improve students' performances, an adaptive educational system must know how an individual learns best. In this context, this work presents an innovative approach for student modeling through probabilistic learning styles combination. Experiments have shown that our approach is able to automatically detect and precisely adjust students' learning styles, based on the non-deterministic and non-stationary aspects of learning styles. Because of the probabilistic an...
Automatic Speaker Recognition System
Directory of Open Access Journals (Sweden)
Parul,R. B. Dubey
2012-12-01
Full Text Available Spoken language is used by human to convey many types of information. Primarily, speech convey message via words. Owing to advanced speech technologies, people's interactions with remote machines, such as phone banking, internet browsing, and secured information retrieval by voice, is becoming popular today. Speaker verification and speaker identification are important for authentication and verification in security purpose. Speaker identification methods can be divided into text independent and text-dependent. Speaker recognition is the process of automatically recognizing speaker voice on the basis of individual information included in the input speech waves. It consists of comparing a speech signal from an unknown speaker to a set of stored data of known speakers. This process recognizes who has spoken by matching input signal with pre- stored samples. The work is focussed to improve the performance of the speaker verification under noisy conditions.
Directory of Open Access Journals (Sweden)
P.KEERTHANAA, K.JEEVITHA, V.NAVINA, G.INDIRA, S.JAYAMANI
2013-07-01
Full Text Available The Primary Aim Of The Project Is To Design, Develop And Implement Automatic Wall Painting Robot Which Helps To Achieve Low Cost Painting Equipment. Despite The Advances In Robotics And Its Wide Spreading Applications, Interior Wall Painting Has Shared Little In Research Activities. The Painting Chemicals Can Cause Hazards To The Human Painters Such As Eye And Respiratory System Problems. Also The Nature Of Painting Procedure That Requires Repeated Work And Hand Rising Makes It Boring, Time And Effort Consuming. When Construction Workers And Robots Are Properly Integrated In Building Tasks, The Whole Construction Process Can Be Better Managed And Savings In Human Labour And Timing Are Obtained As A Consequence. In Addition, It Would Offer The Opportunity To Reduce Or Eliminate Human Exposure To Difficult And Hazardous Environments, Which Would Solve Most Of The Problems Connected With Safety When Many Activities Occur At The Same Time. These Factors Motivate The Development Of An Automated Robotic Painting System.
Automatic alkaloid removal system.
Yahaya, Muhammad Rizuwan; Hj Razali, Mohd Hudzari; Abu Bakar, Che Abdullah; Ismail, Wan Ishak Wan; Muda, Wan Musa Wan; Mat, Nashriyah; Zakaria, Abd
2014-01-01
This alkaloid automated removal machine was developed at Instrumentation Laboratory, Universiti Sultan Zainal Abidin Malaysia that purposely for removing the alkaloid toxicity from Dioscorea hispida (DH) tuber. It is a poisonous plant where scientific study has shown that its tubers contain toxic alkaloid constituents, dioscorine. The tubers can only be consumed after it poisonous is removed. In this experiment, the tubers are needed to blend as powder form before inserting into machine basket. The user is need to push the START button on machine controller for switching the water pump ON by then creating turbulence wave of water in machine tank. The water will stop automatically by triggering the outlet solenoid valve. The powders of tubers are washed for 10 minutes while 1 liter of contaminated water due toxin mixture is flowing out. At this time, the controller will automatically triggered inlet solenoid valve and the new water will flow in machine tank until achieve the desire level that which determined by ultra sonic sensor. This process will repeated for 7 h and the positive result is achieved and shows it significant according to the several parameters of biological character ofpH, temperature, dissolve oxygen, turbidity, conductivity and fish survival rate or time. From that parameter, it also shows the positive result which is near or same with control water and assuming was made that the toxin is fully removed when the pH of DH powder is near with control water. For control water, the pH is about 5.3 while water from this experiment process is 6.0 and before run the machine the pH of contaminated water is about 3.8 which are too acid. This automated machine can save time for removing toxicity from DH compared with a traditional method while less observation of the user. PMID:24783795
30 CFR 56.14115 - Stationary grinding machines.
2010-07-01
... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 56.14115 Section 56.14115 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines....
Stationary states of two-level open quantum systems
International Nuclear Information System (INIS)
A problem of finding stationary states of open quantum systems is addressed. We focus our attention on a generic type of open system: a qubit coupled to its environment. We apply the theory of block operator matrices and find stationary states of two-level open quantum systems under certain conditions applied on both the qubit and the surrounding.
Stationary states of two-level open quantum systems
Gardas, Bartlomiej; Puchala, Zbigniew
2010-01-01
A problem of finding stationary states of open quantum systems is addressed. We focus our attention on a generic type of open system: a qubit coupled to its environment. We apply the theory of block operator matrices and find stationary states of two--level open quantum systems under certain conditions applied both on the qubit and the surrounding.
21 CFR 892.1680 - Stationary x-ray system.
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stationary x-ray system. 892.1680 Section 892.1680 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1680 Stationary x-ray system....
Threshold stationary real exchange rates: a nonlinear, multivariate approach
Philip Shively
2003-01-01
Purchasing power parity implies that real exchange rates are stationary. However, the finding of nonstationary real exchange rates has been difficult to dismiss. Using a nonlinear, three-regime structural bivariate threshold model, this paper finds evidence of threshold stationary real exchange rates which is consistent with purchasing power parity adjusted for market frictions such as transaction costs.
On stationary vacuum solutions to the Einstein equations
Anderson, M T
2000-01-01
It is proved that the only geodesically complete stationary vacuum solution of the Einstein equations is the empty Minkowski space, or a quotient of it by a discrete group of isometries, generalizing a classical result of Lichnerowicz. In addition, we obtain an apriori bound on the curvature of stationary vacuum solutions away from the boundary or horizon.
7 CFR 2902.28 - Stationary equipment hydraulic fluids.
2010-01-01
... designation can be found in the Comprehensive Procurement Guideline, 40 CFR 247.11. EPA provides recovered... 7 Agriculture 15 2010-01-01 2010-01-01 false Stationary equipment hydraulic fluids. 2902.28... PROCUREMENT Designated Items § 2902.28 Stationary equipment hydraulic fluids. (a) Definition....
Analysis of stress and deformation in non-stationary creep
International Nuclear Information System (INIS)
A variational method and its algorithm are presented; they permit the analysis of stress and deformation in non-stationary creep. This algorithm is applied to an infinite cylinder submitted to an internal pressure. The solution obtained is compared with the solution of non-stationary creep problems
Stationary Probability Vectors of Higher-order Markov Chains
Li, Chi-Kwong; Zhang, Shixiao
2013-01-01
We consider the higher-order Markov Chain, and characterize the second order Markov chains admitting every probability distribution vector as a stationary vector. The result is used to construct Markov chains of higher-order with the same property. We also study conditions under which the set of stationary vectors of the Markov chain has a certain affine dimension.
49 CFR 325.59 - Measurement procedure; stationary test.
2010-10-01
... Stationary Test, 40 CFR 202.21. (Table 1 in § 325.7 lists the range of maximum permissible sound level... 49 Transportation 5 2010-10-01 2010-10-01 false Measurement procedure; stationary test. 325.59... CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH...
Bazin, C; Wittich, R; Koutchmy, S; Mouette, J; Nitschelm, C
2015-01-01
We present some new accurate CCD photometry analysis of the white light solar corona at the time of the last 20 March 2015 total eclipse (airborne observations on a Falcon 7X and at ground-based Svalbard). We measured coronal brightness profiles taken along radial directions from 1.001 to 3 solar radii in the northern, southern and equatorial regions, after removing the F corona and the sky background. These studies allow to evaluate the density gradients, structures and temperature heterogeneity, by considering the Thomson scattering in white light of the K corona and also emissions of the EUV Fe XII 193A (1 to 2 MK) and Fe XI 171/174 (lower temperature) simultaneously observed by SDO/AIA and SWAP Proba2 space missions. Some dispersion between the regions is noticed. The limitation of the hydrostatic equilibrium assumption in the solar atmosphere is discussed as well as the contribution of the magnetic field pressure gradients as illustrated by a comparison with the model stationary magnetic corona from Pred...
Xiaohong Liu; Bingqian Liu; Huiling Hu; Ying Liu; Fei Deng; Jian Ge
2013-01-01
Purpose: To investigate the effects of MTP-131 on trabeculum cells cultured under hydrostatic pressure Methods: Glaucomatous human trabecular meshwork (GTM3) cells were divided into three groups: the MTP-131 group, the hydrostatic group, and the normal group. The MTP-131 group was pretreated with 1 µM MTP-131, and the cells were then cultured under 80 mmHg pressure for 24 hours. The normal group was cultured under normal atmospheric pressure for 24 h, and the hydrostatic group was cultured...
Makarov, M. V.
2011-06-01
An experimental study was undertaken to reveal the influence of the hydrostatic pressure on the early developmental stages of Laminaria saccharina, including the motile zoospores, the embryospores, and sprouting spores. The pressure did not affect the moving patterns and sinking rate of the zoospores. The sprouting spores were the most vulnerable among the other types; i.e., a pressure of 3 standard atmospheres (the hydrostatic pressure at the depth of 30 m) delayed or disturbed their development. The light conditions did not limit the vertical distribution of L. saccharina to greater depths. We assume that the hydrostatic pressure may significantly impact the vertical distribution of benthic macrophytes in the sublittoral zone.
Polarimetric SAR Image Object Segmentation via Level Set with Stationary Global Minimum
Directory of Open Access Journals (Sweden)
Shuai Yongmin
2010-01-01
Full Text Available We present a level set-based method for object segmentation in polarimetric synthetic aperture radar (PolSAR images. In our method, a modified energy functional via active contour model is proposed based on complex Gaussian/Wishart distribution model for both single-look and multilook PolSAR images. The modified functional has two interesting properties: (1 the curve evolution does not enter into local minimum; (2 the level set function has a unique stationary convergence state. With these properties, the desired object can be segmented more accurately. Besides, the modified functional allows us to set an effective automatic termination criterion and makes the algorithm more practical. The experimental results on synthetic and real PolSAR images demonstrate the effectiveness of our method.
Growth of microalgae in autotrophic stationary systems
Directory of Open Access Journals (Sweden)
Paulo Cunha
2008-06-01
Full Text Available In this paper we evaluate the growth of nine marine microalgae species (Nannochloropsis oculata, Thalassiosira pseudonana, Phaeodactylum tricornutum, Isochrysis galbana, Tetraselmis suecica, Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira fluviatilis and Isochrysis sp. and one freshwater species (Chlorella vulgaris under stationary autotrophy conditions, using erlenmeyers fl asks with 800mL of culture medium exposed to constant light intensities providing a photon flux density of about 150μmol.m-2.s-1 and 25±2oC temperature and constant air flow. The experiment was carried out in a controlled environment considering a block delineating randomized over time with three replicates. The Nannochloropsis oculata showed the highest value of maximum cellular density, but with a longer period of time and a lower growth rate. This was probably due to its tiny cell size, demanding a large number of cells per volume to attain its optimum conditions for light, nutrients, water and atmospheric carbon dioxide. In addition, in spite of showing one of the lowest values of maximum cellular density, Thalassiosira fluviatilis was the species that reached its maximum in a short period of time at the highest growth rate. Chlorella vulgaris was the only freshwater species tested and it showed the poorest performance for all the variables analyzed in the current study.
Baroclinic stationary waves in aquaplanet models
Zappa, Giuseppe; Navarra, Antonio; 10.1175/2011JAS3573.1
2011-01-01
An aquaplanet model is used to study the nature of the highly persistent low frequency waves that have been observed in models forced by zonally symmetric boundary conditions. Using the Hayashi spectral analysis of the extratropical waves, we find that a quasi-stationary (QS) wave five belongs to a wave packet obeying a well defined dispersion relation with eastward group velocity. The components of the dispersion relation with k>5 baroclinically convert eddy available potential energy into eddy kinetic energy, while those with k<5 are baroclinically neutral. In agreement with the Green's model of baroclinic instability, the wave five is weakly unstable, and the inverse energy cascade, which had been previously proposed as a main forcing for this type of waves, only acts as a positive feedback on its predominantly baroclinic energetics. The QS wave is reinforced by a phase lock to an analogous pattern in the tropical convection, which provides further amplification to the wave. We also find that the Pedlos...
Quasi-stationary distributions and population processes
Méléard, Sylvie
2011-01-01
This survey concerns the study of quasi-stationary distributions with a specific focus on models derived from ecology and population dynamics. We are concerned with the long time behavior of different stochastic population size processes when 0 is an absorbing point almost surely attained by the process. The hitting time of this point, namely the extinction time, can be large compared to the physical time and the population size can fluctuate for large amount of time before extinction actually occurs. This phenomenon can be understood by the study of quasi-limiting distributions. In this paper, general results on quasi-stationarity are given and examples developed in detail. One shows in particular how this notion is related to the spectral properties of the semi-group of the process killed at 0. Then we study different stochastic population models including nonlinear terms modeling the regulation of the population. These models will take values in countable sets (as birth and death processes) or in continuou...
On-Shell Description of Stationary Flames
Kazakov, K A
2004-01-01
The problem of non-perturbative description of stationary flames with arbitrary gas expansion is considered. On the basis of the Thomson circulation theorem an implicit integral of the flow equations is constructed. With the help of this integral, a simple explicit expression for the vortex mode of the burnt gas flow near the flame front is obtained. Furthermore, a dispersion relation for the potential mode at the flame front is written down, thus reducing the initial system of bulk equations and jump conditions for the flow variables to a set of integro-differential equations for the flame front position and the flow velocity at the front. The developed approach is applied to the case of zero-thickness flames. An equation accounting the transfer processes in the flame front is also obtained. Finally, an asymptotic expansion of the derived equations is carried out in the case \\theta\\to 1 where \\theta is the gas expansion coefficient, and a single equation for the front position is obtained in the first post-S...
An experimental stationary quadrotor with variable DOF
Indian Academy of Sciences (India)
Vasfi Emre Ömürlü; Utku Büyükşahin; Remzi Artar; Ahmet Kirli; M Nurullah Turgut
2013-04-01
Unmanned air vehicles (UAV) and especially quadrotors have drawn great attention in recent years because of their maneuverability, ease of design and control. Most of the works concentrate mostly on control; yet, design and communication are also some sub-topics. In this research, a stationary, four rotor air vehicle with limited/controlled degree of freedom is constructed so that various control algorithms and their changing effects with varying vehicle dynamics can be studied on the ground for safety purposes. Ascending/descending, pitch/yaw/roll motions can be limited/controlled by setting the vehicle’s degree of freedom mechanically, resulting better net observability of the control algorithms on the vehicle’s dynamic performance. Design, in terms of mechanics, mechatronics and software is presented and the usability of the system is shown. Parallel self tuning fuzzy PD + PD control is applied to the system for preliminary studies and results are discussed. Inspite of the sensor noise, satisfactory pitch/roll/yaw control is achieved.
Stationary power fuel cell commercialization status worldwide
Energy Technology Data Exchange (ETDEWEB)
Williams, M.C. [Dept. of Energy, Morgantown, WV (United States)
1996-12-31
Fuel cell technologies for stationary power are set to play a role in power generation applications worldwide. The worldwide fuel cell vision is to provide powerplants for the emerging distributed generation and on-site markets. Progress towards commercialization has occurred in all fuel cell development areas. Around 100 ONSI phosphoric acid fuel cell (PAFC) units have been sold, with significant foreign sales in Europe and Japan. Fuji has apparently overcome its PAFC decay problems. Industry-driven molten carbonate fuel cell (MCFC) programs in Japan and the U.S. are conducting megawatt (MW)-class demonstrations, which are bringing the MCFC to the verge of commercialization. Westinghouse Electric, the acknowledged world leader in tubular solid oxide fuel cell (SOFC) technology, continues to set performance records and has completed construction of a 4-MW/year manufacturing facility in the U.S. Fuel cells have also taken a major step forward with the conceptual development of ultra-high efficiency fuel cell/gas turbine plants. Many SOFC developers in Japan, Europe, and North America continue to make significant advances.
Model of non-stationary, inhomogeneous turbulence
Bragg, Andrew D.; Kurien, Susan; Clark, Timothy T.
2016-07-01
We compare results from a spectral model for non-stationary, inhomogeneous turbulence (Besnard et al. in Theor Comp Fluid Dyn 8:1-35, 1996) with direct numerical simulation (DNS) data of a shear-free mixing layer (SFML) (Tordella et al. in Phys Rev E 77:016309, 2008). The SFML is used as a test case in which the efficacy of the model closure for the physical-space transport of the fluid velocity field can be tested in a flow with inhomogeneity, without the additional complexity of mean-flow coupling. The model is able to capture certain features of the SFML quite well for intermediate to long times, including the evolution of the mixing-layer width and turbulent kinetic energy. At short-times, and for more sensitive statistics such as the generation of the velocity field anisotropy, the model is less accurate. We propose two possible causes for the discrepancies. The first is the local approximation to the pressure-transport and the second is the a priori spherical averaging used to reduce the dimensionality of the solution space of the model, from wavevector to wavenumber space. DNS data are then used to gauge the relative importance of both possible deficiencies in the model.
The Parametric Identification Of A Stationary Process
Directory of Open Access Journals (Sweden)
Radu BELEA
2003-12-01
Full Text Available In the problems of identification it is supposed that the process has at least one measurable input size and at least one measurable output size. The identification of a process has three stages: the obtaining of a registration of process measurable sizes; the choice of a proper mathematical model for the process; the extract of the parameter values of the mathematical models from registered data. The parametric identification problem is an optimization problem, in which the best combination of values for the model parameters set is searched. In the paper is presented the parametric identification of a water flow process in a laboratory stand. The identification had the following dims: detailed understanding of how the stand works, finding a new illustrative experiment for the stand, the application of advanced techniques of automat control, and the development of a project of new stand, meant to allow a large variety of experiments.
Making automatic differentiation truly automatic : coupling PETSc with ADIC
International Nuclear Information System (INIS)
Despite its name, automatic differentiation (AD) is often far from an automatic process. often one must specify independent and dependent variables, indicate the derivative quantities to be computed, and perhaps even provide information about the structure of the Jacobians or Hessians being computed. However, when AD is used in conjunction with a toolkit with well-defined interfaces, many of these issues do not arise. They describe recent research into coupling the ADIC automatic differentiation tool with PETSc, a toolkit for the parallel numerical solution of PDEs. This research leverages the interfaces and objects of PETSc to make the AD process very nearly transparent
Bayesian soft X-ray tomography using non-stationary Gaussian Processes
International Nuclear Information System (INIS)
In this study, a Bayesian based non-stationary Gaussian Process (GP) method for the inference of soft X-ray emissivity distribution along with its associated uncertainties has been developed. For the investigation of equilibrium condition and fast magnetohydrodynamic behaviors in nuclear fusion plasmas, it is of importance to infer, especially in the plasma center, spatially resolved soft X-ray profiles from a limited number of noisy line integral measurements. For this ill-posed inversion problem, Bayesian probability theory can provide a posterior probability distribution over all possible solutions under given model assumptions. Specifically, the use of a non-stationary GP to model the emission allows the model to adapt to the varying length scales of the underlying diffusion process. In contrast to other conventional methods, the prior regularization is realized in a probability form which enhances the capability of uncertainty analysis, in consequence, scientists who concern the reliability of their results will benefit from it. Under the assumption of normally distributed noise, the posterior distribution evaluated at a discrete number of points becomes a multivariate normal distribution whose mean and covariance are analytically available, making inversions and calculation of uncertainty fast. Additionally, the hyper-parameters embedded in the model assumption can be optimized through a Bayesian Occam's Razor formalism and thereby automatically adjust the model complexity. This method is shown to produce convincing reconstructions and good agreements with independently calculated results from the Maximum Entropy and Equilibrium-Based Iterative Tomography Algorithm methods
Stationary point of the radiometric control of cesium contamination of agricultural animals
International Nuclear Information System (INIS)
Stationary point of the radiometric control of cesium contamination of an agricultural animals. Is intended for vital measurements of the contents of radiocesium in muscular tissue of a cattle. Can be used on cattle-breeding farms, providing points, in meat factories and personal facilities. As a base means for accommodation of the control point the motor-car is used. Design of the car allows to automate operations on deployment of the control point on a place and translation of one to a transport mode. Limits of measured specific activity of cesium contamination of a cattle is up 5*10-9 to 5*10-6 Ci/kg. The basic error on the bottom limit of measurement at confidence coefficient 0,95 is no more than 30%. Measurement time for the bottom limit of determined specific activity is no more than 30 s. There is automatic measurement mode. Type of a power is 220 V, 50 Hz. Range of working temperatures is up -15 to +35 centigrade. Relative humidity is no more than 98% at 25 centigrade. External gamma background is till 0.035 mR/h. Time of installation and dismantle of stationary control point is no more than 1,5 hours. The direct radiometric control in divo allows to fulfil and to use biotechnological process of removing of cesium isotopes from body of animals for decrease of levels of radioactive contamination
Directory of Open Access Journals (Sweden)
Ferreira S.T.
2005-01-01
Full Text Available In the last few years, hydrostatic pressure has been extensively used in the study of both protein folding and misfolding/aggregation. Compared to other chemical or physical denaturing agents, a unique feature of pressure is its ability to induce subtle changes in protein conformation, which allow the stabilization of partially folded intermediate states that are usually not significantly populated under more drastic conditions (e.g., in the presence of chemical denaturants or at high temperatures. Much of the recent research in the field of protein folding has focused on the characterization of folding intermediates since these species appear to be involved in a variety of disease-causing protein misfolding and aggregation events. The exact mechanisms of these biologicalphenomena, however, are still poorly understood. Here, we review recent examples of the use of hydrostatic pressure as a tool to obtain insight into the forces and energetics governing the productive folding or the misfolding and aggregation of proteins.
Hydrostatic pressure and temperature calibration based on phase diagram of bismuth
Wang, Zhigang; Liu, Yonggang; Bi, Yan; Song, Wei; Xie, Hongsen
2012-06-01
Under high-temperature and high pressure (HTHP) experiments, materials of small elastic modulus deform easily, and the length of the sample can be hardly predicted which lead to failure of ultrasonic velocity measurement. In this paper, a hydrostatic assembly of the sample for ultrasonic measurements is designed under HPHT, which can prevent plastic deformation. According to the abrupt change of travel time of the sample across the different phase boundaries of bismuth, the correspondent relation of sample pressure and oil pressure of multi-anvil apparatus can be calibrated, and the relation of sample temperature and temperature measured by thermocouple can also be determined. Sample pressure under high temperature is also determined by ultrasonic results. It is believed that the new sample assembly of hydrostatic pressure is valid and feasible for ultrasonic experiments under HTHP.
International Nuclear Information System (INIS)
Bacterial spores are inactivated by moderate hydrostatic pressures. The radiation dose required to sterilize radiation sensitive pharmaceuticals can be considerably reduced using a combination hydrostatic pressure-radiation treatment. This paper describes a combination pressure-radiation sterilization process using Bacillus pumilus spores suspended in water, 0.9% saline, and 5% dextrose solutions. The optimum temperatures for spore inactivation at 35 MPa and the degree of inactivation at 35, 70 and 105 MPa applied for times up to 100 min have been determined. Inactivation was greatest in saline and least in dextrose. Spores in dextrose were only slightly less radiation resistant than in saline or water. It was calculated that the radiation dose required for sterilization could be halved with appropriate compression treatment. Examples of combinations of pressure-radiation suitable for sterilization are given. One combination is compression at 105 MPa for 18 min for a dose of 1.25 Mrad. (author)
The Effect of Hydrostatic Pressure and Seismic Load on ITER Lower Cryopump Ports
International Nuclear Information System (INIS)
The lower cryopump ports in International Thermonuclear Experimental Reactor (ITER) as a part of the vacuum vessel play many important roles. As the boundary of vacuum it must be ensured against structural damage. In this study a finite element model of the lower cryopump ports was developed by ANSYS code with a purpose to evaluate the stress and displacement level on it. Two kinds of loads were taken into account. One was the hydrostatic pressure including the normal operation pressure and test pressure. The other was the seismic load. The analysis results show that the peak stress does not exceed the allowable stress for either the hydrostatic pressure or the seismic load according to the ITER structural design criterion, which indicates that the structure has a good safety margin
High hydrostatic pressure effect on behaviour of SmS crystals under deformation
International Nuclear Information System (INIS)
Experiments are carried out on the deformation of SmS monocrystals by uniaxial compression under high (up to 10 kbar) hydrostatic pressure. It is shown that on the whole dependences of mechanical characteristics of samarium monosulfide on the pressure are qualitatively similar to analogous dependences for other materials. While in the quantitative respect effects in samarium monosulfide are much higher, which is evidently connected with high compressibility of semiconducting SmS. It is found that in the result of uniaxial com-- pression of SmS crystals under hydrostatic pressure less than 6.5 kbar, a phase transition analogous to the semiconductor-metal transition under poressure, takes ptace in them
Fumagalli, Michele; Hunt, Leslie K
2010-01-01
Stars in galaxies form in giant molecular clouds that coalesce when the atomic hydrogen is converted into molecules. There are currently two dominant models for what property of the galactic disk determines its molecular fraction: either hydrostatic pressure driven by the gravity of gas and stars, or a combination of gas column density and metallicity. To assess the validity of these models, we compare theoretical predictions to the observed atomic gas content of low-metallicity dwarf galaxies with high stellar densities. The extreme conditions found in these systems are optimal to distinguish the two models, otherwise degenerate in nearby spirals. Locally, on scales <100 pc, we find that the state of the interstellar medium is mostly sensitive to the gas column density and metallicity rather than hydrostatic pressure. On larger scales where the average stellar density is considerably lower, both pressure and shielding models reproduce the observations, even at low metallicity. We conclude that models base...
DEFF Research Database (Denmark)
Du, Yutao; Lin, Lin; Schmidt, Mette;
2008-01-01
An innovative technique, called the high hydrostatic pressure (HHP) treatment, has been recently reported to improve the cryosurvival of gametes or embryos in certain mammalian species. The aim of the present study was to investigate the in vitro and in vivo developmental competence and...... cryotolerance of embryos produced by handmade cloning (HMC) after pressure treatment of recipient oocytes. In vitro-matured porcine oocytes were treated with a sublethal hydrostatic pressure of 20 MPa (200 times greater than atmospheric pressure) and recovered for either 1 or 2 h (HHP1 and HHP2 groups...... day 5 of the estrous cycle. One recipient was diagnosed pregnant and gave birth to two healthy piglets by naturally delivery on day 122 of gestation. This pilot study proved that the sublethal HHP treatment of porcine oocytes before HMC results in improved in vitro developmental competence and...
Effect of Hydrostatic Pressure on BiS2-Based Layered Superconductors: A Review
Jha, Rajveer; Awana, V. P. S.
2016-04-01
We report impact of hydrostatic pressure on the newly discovered BiS2 based superconductors. In last couple of years the new BiS2 based superconductor attracted great attention of the condensed matter physics community. These new layered BiS2-based compounds are very sensitive to the concentration of carriers doping and pressure that cause profound changes in their physical properties with appearance of superconductivity in the vicinity of their insulating/semiconducting state. The BiS2-based new compounds are expected to provide us with the next stage of exploring new superconductors and to discuss their exotic superconductivity mechanisms. In current review, we present most of our findings related to impact of hydrostatic pressure on superconductivity of new BiS2 based superconductors at one place.
Structure and properties of nano-sized Eurofer 97 steel obtained by hydrostatic extrusion
International Nuclear Information System (INIS)
The objective of the present work was to apply hydrostatic extrusion to Eurofer 97 steel - a fusion relevant material that can be used for structural application in ITER. Samples were hydrostatically extruded in a multi-step process with a total true strain of about 4. Microstructure observations via light and transmission electron microscopy revealed significant grain size refinement from about 400 nm to 90 nm and changes in carbide size and distribution. Microstructure changes resulted in substantial improvement in mechanical properties of the material (the ultimate tensile strength and yield stress increase from 691 MPa to 1769 MPa and 582 MPa to 1641 MPa, respectively) which were evaluated by hardness measurements and tensile tests.
The Effect of Additives on The Performance of HydrostaticThrust Bearings
Directory of Open Access Journals (Sweden)
Muhammed Abdul Sattar
2008-01-01
Full Text Available The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed. Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness. The theoretical results show an increase in load capacity by (8.3% in the presence of solid graphite particles with concentration of (16% by weight as compared with pure oil, with increasing shear stress. . In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate, pumping power subjected to centrifugal parameter (S, recess position (r1, film thickness ratio (, particle concentration (.
Electrical Conductivity of Fine Crystalline Graphite under the Influence of the Hydrostatic Pressure
Directory of Open Access Journals (Sweden)
I.V. Ovsiienko
2016-06-01
Full Text Available It was investigated the influence of hydrostatic pressure on the electrical conductivity of crystalline graphite in temperature range (77-293 K. It was revealed that the reducing of electrical resistivity in specimens of fine crystalline graphite under the action of hydrostatic pressure is due to increasing of overlap between valence and conduction bands that leads to increase of the concentration of free charge carriers. The change of the overlap of valence and conduction bands was estimated. It is shown the decrease of the distance between the graphite layers under pressure is irreversible process, when load is remove the electric resistance increases slightly, but does not acquire the initial value.
High hydrostatic pressure adaptive strategies in an obligate piezophile Pyrococcus yayanosii
Michoud, Grégoire; Jebbar, Mohamed
2016-01-01
Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins. PMID:27250364
Second harmonic generation in an asymmetric rectangular quantum well under hydrostatic pressure
International Nuclear Information System (INIS)
The effects of structure parameters and hydrostatic pressure on the electronic states and the second harmonic generation (SHG) susceptibility of asymmetric rectangular quantum well (ARQW) are studied. The asymmetry of the potential can be controlled by changing the structural parameters and this adjustable asymmetry is important for optimizing the SHG susceptibility. We have calculated analytically the electronic states in ARQW within the framework of the envelope function approach. Numerical results for Al xl Ga1-xl As/GaAs/Al xr Ga1-xr As quantum well are presented. The results obtained show that the hydrostatic pressure and the structure parameters of ARQW significantly influence the SHG susceptibility. This behavior in the SHG susceptibility gives a new degree of freedom in regions of interest for device applications
Soda-lime silicate glass under hydrostatic pressure and indentation: a micro-Raman study
International Nuclear Information System (INIS)
Raman micro-spectroscopy is used to analyse the plastic behaviour of window glass (a soda-lime silicate glass) under high hydrostatic pressure and Vickers indentation. We show pressure-induced irreversible structural changes, notably an increase of Q2 species at the expense of Q3. For the first time, a very accurate Raman↔pressure calibration curve has been established. Local density variations of a Vickers indented window glass have been characterized by micro-Raman mapping using a high spatial resolution device. The effects of glass depolymerization on indentation and hydrostatic compression are discussed. Differences between window glass and pure SiO2 glass behaviour under high stresses are also highlighted and analysed at a local scale.
High hydrostatic pressure adaptive strategies in an obligate piezophile Pyrococcus yayanosii
Michoud, Gregoire
2016-06-02
Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins.
High hydrostatic pressure adaptive strategies in an obligate piezophile Pyrococcus yayanosii
Michoud, Grégoire; Jebbar, Mohamed
2016-06-01
Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins.
Hydrostatic pressure dependence of transformation temperatures of Ti-Ni-Cu alloys
International Nuclear Information System (INIS)
The transformation start temperatures of shape memory Ti50Ni50-xCux (x = 2, 3, 5, 12.5) alloys under hydrostatic pressures were obtained by resistivity measurements, and their thermodynamical analysis was made by using Clausius-Clapeyron equation. The obtained results are the followings. (1) As hydrostatic pressure increases, transformation temperatures (Ms and Af) of the B2 B19' transformation increase linearly for the 2Cu and 3Cu alloys, but decrease linearly for the 5Cu alloy. (2) For the 12.5Cu alloy, Ms and Af of B2 B19 transformation increase but those of B19 B19' transformation decrease as pressure increases. (3) The copper content dependence of volume change associated with martensitic transformation, which is calculated by Clausius-Clapeyron equation, suggests that the 5Cu alloy transforms in two steps B2 → B19 → B19' although it is believed to transform in one step. (orig.)
Automatic Kurdish Dialects Identification
Directory of Open Access Journals (Sweden)
Hossein Hassani
2016-02-01
Full Text Available Automatic dialect identification is a necessary Lan guage Technology for processing multi- dialect languages in which the dialects are linguis tically far from each other. Particularly, this becomes crucial where the dialects are mutually uni ntelligible. Therefore, to perform computational activities on these languages, the sy stem needs to identify the dialect that is the subject of the process. Kurdish language encompasse s various dialects. It is written using several different scripts. The language lacks of a standard orthography. This situation makes the Kurdish dialectal identification more interesti ng and required, both form the research and from the application perspectives. In this research , we have applied a classification method, based on supervised machine learning, to identify t he dialects of the Kurdish texts. The research has focused on two widely spoken and most dominant Kurdish dialects, namely, Kurmanji and Sorani. The approach could be applied to the other Kurdish dialects as well. The method is also applicable to the languages which are similar to Ku rdish in their dialectal diversity and differences.
International Nuclear Information System (INIS)
In this work we present the results obtained from the calculation of the level structure of a n-type delta-doped well Field Effect Transistor when is subjected to hydrostatic pressure. We study the energy level structure as a function of hydrostatic pressure within the range of 0 to 6 kbar for different Schottky barrier height (SBH). We use an analytical expression for the effect of hydrostatic pressure on the SBH and the pressure dependence of the basic parameters of the system as the effective mass m(P) and the dielectric constant ε(P) of GaAs. We found that due to the effects of hydrostatic pressure, in addition to electronic level structure alteration, the profile of the differential capacitance per unit area C−2 is affected
A global non-hydrostatic dynamical core using the spectral element method on a cubed-sphere grid
Choi, Suk-Jin; Hong, Song-You
2016-06-01
A new global model with a non-hydrostatic (NH) dynamical core is developed. It employs the spectral element method (SEM) in the horizontal discretization and the finite difference method (FDM) in the vertical discretization. The solver includes a time-split third-order Runge-Kutta (RK3) time-integration technique. Pursuing the quasi-uniform and pole singularity-free spherical geometry, a cubed-sphere grid is employed. To assess the performance of the developed dynamical solver, the results from a number of idealized benchmark tests for hydrostatic and non-hydrostatic flows are presented and compared. The results indicate that the non-hydrostatic dynamical solver is able to produce solutions with good accuracy and consistency comparable to reference solutions. Further evaluation of the model with a full-physics package demonstrates its capability in reproducing heavy rainfall over the Korean Peninsula, which confirms that coupling of the dynamical solver and full-physics package is robust.
Energy Technology Data Exchange (ETDEWEB)
Carlos-Pinedo, C.; Rodríguez-Vargas, I.; Martínez-Orozco, J. C. [Unidad Académica de Física. Universidad Autónoma de Zacatecas. Calzada Solidaridad Esquina con Paseo la Bufa S/N. C.P. 98060, Zacatecas, Zac. (Mexico)
2014-05-15
In this work we present the results obtained from the calculation of the level structure of a n-type delta-doped well Field Effect Transistor when is subjected to hydrostatic pressure. We study the energy level structure as a function of hydrostatic pressure within the range of 0 to 6 kbar for different Schottky barrier height (SBH). We use an analytical expression for the effect of hydrostatic pressure on the SBH and the pressure dependence of the basic parameters of the system as the effective mass m(P) and the dielectric constant ε(P) of GaAs. We found that due to the effects of hydrostatic pressure, in addition to electronic level structure alteration, the profile of the differential capacitance per unit area C{sup −2} is affected.
International Nuclear Information System (INIS)
This paper refers to testing procedures of the production capacity of heavy water production pilot, industrial scale plants and of heavy water reconcentration facilities. Simulation codes taking into account the mass and heat transfers inside the exchange columns were developed. These codes provided valuable insight about the isotope build-up of the installation which allowed estimating the time of reaching the stationary regime. Also transient regimes following perturbations in the operating parameters (i.e. temperature, pressure, fluid rates) of the installation were simulated and an optimal rate of routine inspections and adjustments was thus established
Modernization of the Hydrostatic Drive of Lower Gate Locks in Waterworks Gabcikovo
Stračár, Karol
2011-12-01
This paper deals with analysis of the combined load on hydraulic cylinder. Based on measurements of the parameters of the hydraulic cylinder and accurate calculations conclusions were drawn. Measurements were made on the lower hydrostatic drive gate locks at the waterworks Gabcikovo. Method of fixation of the hydraulic cylinder creates added bending torques which causes deformation of piston rod. The results are an effort to find relationship between dimensions, loading and safe operation.
PRAVEEN KUMAR; CHRIS CHU; DUDUKU KRISHNAIAH; AWANG BONO
2006-01-01
A modified version of high hydrostatic pressure extraction has been performed for extraction of antioxidants from M. citrifolia fruit at 5, 15, 25 bar and temperature 30° to 70°C for time duration 1, 2, 4 and 6 hours. The antioxidant activity of the extracts was determined by di-phenylpicrylhydrazyl radical scavenging method. The process parameters were optimized for antioxidant activity by central composite design method of response surface methodology using the statistical package, design e...
Effect of hydrostatic pressure on the tensile properties of alpha uranium
International Nuclear Information System (INIS)
This report examines the effect of a superimposed hydrostatic pressure on the tensile properties of four grades of rolled unalloyed alpha uranium. The materials varied in carbon content and heat treatment. The principal effect of increasing pressure is an increase in the ductility of the materials. By not heat treating the uranium after the rolling process, the interaction of carbon content on mechanical properties is almost nullified. (author)
Pham Hieu Liem; Naoki Morimoto; Atsushi Mahara; Chizuru Jinno; Koji Shima; Shuichi Ogino; Michiharu Sakamoto; Natsuko Kakudo; Masukazu Inoie; Kenji Kusumoto; Toshia Fujisato; Shigehiko Suzuki; Tetsuji Yamaoka
2015-01-01
We have reported that high-hydrostatic-pressure (HHP) technology is safe and useful for producing various kinds of decellularized tissue. However, the preparation of decellularized or inactivated skin using HHP has not been reported. The objective of this study was thus to prepare inactivated skin from human skin using HHP, and to explore the appropriate conditions of pressurization to inactivate skin that can be used for skin reconstruction. Human skin samples of 8 mm in diameter were packed...
Israel, H.; Schellenberger, G.; Nevalainen, J.; Massey, R; Reiprich, T. H.
2014-01-01
The mass of galaxy clusters can be inferred from the temperature of their X-ray emitting gas, $T_{\\mathrm{X}}$. Their masses may be underestimated if it is assumed that the gas is in hydrostatic equilibrium, by an amount $b^{\\mathrm{hyd}}\\sim(20\\pm10)$ % suggested by simulations. We have previously found consistency between a sample of observed \\textit{Chandra} X-ray masses and independent weak lensing measurements. Unfortunately, uncertainties in the instrumental calibration of {\\em Chandra}...
Filtration coefficient of the axon membrane as measured with hydrostatic and osmotic methods.
Vargas, F F
1968-01-01
The hydraulic conductivity of the membranes surrounding the giant axon of the squid, Dosidicus gigas, was measured. In some axons the axoplasm was partially removed by suction. Perfusion was then established by insertion of a second pipette. In other axons the axoplasm was left intact and only one pipette was inserted. In both groups hydrostatic pressure was applied by means of a water column in a capillary manometer. Displacement of the meniscus in time gave the rate of fluid flowing across the axon sheath. In both groups osmotic differences across the membrane were established by the addition of a test molecule to the external medium which was seawater. The hydraulic conductivity determined by application of hydrostatic pressure was 10.6 +/- 0.8.10(-8) cm/sec cm H(2)O in perfused axons and 3.2 +/- 0.6.10(-8) cm/sec cm H(2)O in intact axons. When the driving force was an osmotic pressure gradient the conductivity was 4.5 +/- 0.6 x 10(-10) cm/sec cm H(2)O and 4.8 +/- 0.9 x 10(-10) cm/sec cm H(2)O in perfused and intact axons, respectively. A comparable result was found when the internal solution was made hyperosmotic. The fluid flow was a linear function of the hydrostatic pressure up to 70 cm of water. Glycerol outflux and membrane conductance were increased 1.6 and 1.1 times by the application of hydrostatic pressure. These increments do not give an explanation of the difference between the filtration coefficients. Other possible explanations are suggested and discussed. PMID:5642470
High pressure study of BaFe2As2 - role of hydrostaticity and uniaxial stress
Duncan, W. J.; Welzel, O. P.; Harrison, C; X. F. Wang(Henan Normal University, Xinxiang, P. R. China); Chen, X. H.; F. M. Grosche; Niklowitz, P. G.
2009-01-01
We investigate the evolution of the electrical resistivity of BaFe2As2 single crystals with pressure. The samples used were from the same batch grown from self flux and showed properties that were highly reproducible. Samples were pressurised using three different pressure media: pentane-isopentane (in a piston cylinder cell), Daphne oil (in an alumina anvil cell) and steatite (in a Bridgman cell). Each pressure medium has its own intrinsic level of hydrostaticity, which dramatically affects ...
Hydrostatic Vibratory Drive of the Test Stand for Excitation of the Amplitude-Modulated Vibrations
Nizhegorodov, A. I.; Gavrilin, A. N.; Moyzes, B. B.
2016-01-01
The article reviews the problems arising during the development of the test stand hydrostatic vibratory drive, which synthesize controlled amplitude-modulated vibrations required testing of vibration strength and vibrostability of technological devices. The newly developed modification can adequately simulate the transport vibration and vibration of the operating power-supply units of technological machinery vibration by means of implementing of a continuous frequency spectrum of the vibration exposure in the desired frequency range.
The effects of defects on copper melting under hydrostatic and shock loading
Energy Technology Data Exchange (ETDEWEB)
Luo, Shengnian [Los Alamos National Laboratory; An, Qi [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Han, Li - Bo [USTC
2009-07-24
With molecular dynamics (MD) simulations, we investigate the effects of defects on Cu melting under hydrostatic and shock wave loading. We explore preexistent defects including vacancies, stacking faults and grain boundaries, as well as shock-induced defects. Depending on defect characteristics (energy and concentration), defects may have negligible or considerable effects on melting at MD scales However, it is expected that defects have more pronounced effects at heating rates lower than the MD rates.
WEIGHING GALAXY CLUSTERS WITH GAS. I. ON THE METHODS OF COMPUTING HYDROSTATIC MASS BIAS
International Nuclear Information System (INIS)
Mass estimates of galaxy clusters from X-ray and Sunyeav-Zel'dovich observations assume the intracluster gas is in hydrostatic equilibrium with their gravitational potential. However, since galaxy clusters are dynamically active objects whose dynamical states can deviate significantly from the equilibrium configuration, the departure from the hydrostatic equilibrium assumption is one of the largest sources of systematic uncertainties in cluster cosmology. In the literature there have been two methods for computing the hydrostatic mass bias based on the Euler and the modified Jeans equations, respectively, and there has been some confusion about the validity of these two methods. The word 'Jeans' was a misnomer, which incorrectly implies that the gas is collisionless. To avoid further confusion, we instead refer these methods as 'summation' and 'averaging' methods respectively. In this work, we show that these two methods for computing the hydrostatic mass bias are equivalent by demonstrating that the equation used in the second method can be derived from taking spatial averages of the Euler equation. Specifically, we identify the correspondences of individual terms in these two methods mathematically and show that these correspondences are valid to within a few percent level using hydrodynamical simulations of galaxy cluster formation. In addition, we compute the mass bias associated with the acceleration of gas and show that its contribution is small in the virialized regions in the interior of galaxy clusters, but becomes non-negligible in the outskirts of massive galaxy clusters. We discuss future prospects of understanding and characterizing biases in the mass estimate of galaxy clusters using both hydrodynamical simulations and observations and their implications for cluster cosmology
Hydrostatic pressure and strain effects in short period InN/GaN superlattices
DEFF Research Database (Denmark)
Gorczyca, I.; Suski, T.; Christensen, Niels Egede; Svane, Axel
2012-01-01
the superlattice geometry. The superlattice gap vanishes for n = m ≥ 4. These effects are related to the existence of the internal electric fields that strongly influence the valence- and conduction-band profiles and thus determine the effective band gap and emission energies. The electric field...... strength depends strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....
The Effect of Additives on The Performance of HydrostaticThrust Bearings
Muhammed Abdul Sattar; Albert E. Yousif
2008-01-01
The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed. Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness. The theoretical results show an increase in load capacity by (8.3%) in the presence of solid graphite particles with concentration...
Applied Energy Systems: Hydrostatic Fluid Power Transmission and Flow in Pipes
McGovern, Jim
2012-01-01
This is an intentionally compact textbook or set of notes for a module addressing basic Fluid Mechanics for incompressible fluids within the context of Applied Energy Systems. Rather than attempting to cover Fluid Mechanics in a very broad and general way, two practical areas are selected in the use of fluids: hydrostatic power transmission systems and the flow of fluids through pipes and fittings. This allows the two areas to be presented in some detail, but also allows them to be sample app...
Model Identification of Hydrostatic Center Frame Control System based on MATLAB
Zhongwen Wang; Ruizhen Duan; Xiaoqiu Xu
2013-01-01
The composition and principle of an electro-hydraulic servo oil film stiffness control system of hydrostatic center frame will be introduced, and the system model identification as well as the verification will be carried out based on semi-physical simulation environment of Real-time Workshop (RTW) and system identification toolbox in MATLAB. A control strategy of fuzzy sliding model variable structure will be presented , and it is applied in the model achieved by identifications, adopting th...
Innovation in the development and improvement of meat products: High hydrostatic pressures
Gallardo, Claudia; Garcia-Garcia, Rebeca; Welti-Chanes, Jorge
2015-01-01
One focus of interest in the development of products and processes of the food industry is related to the reduction in the use of additives that could have negative effects on consumer health. This view called cleaning nutritional label is aimed at the partial or total substitution of additives by other factors that do not have these negative effects and maintain the safety and quality of the products processed. The high hydrostatic pressure (HHP) is one of the new conservation factors used t...
Stationary phases for superheated water chromatography
International Nuclear Information System (INIS)
This project focused on the comparison of conventional liquid chromatography and superheated water chromatography. It examined the differences in efficiency and retention of a range of different stationary phases. Alkyl aryl ketones and eight aromatic compounds were separated on PBD-zirconia, Xterra RP 18, Luna C18 (2) and Oasis HLB columns using conventional LC and superheated water chromatography system. The retention indices were determined in the different eluents. On changing the organic component of the eluent from methanol to acetonitrile to superheated water considerable improvements were found in the peak shapes and column efficiencies on the PBD-zirconia and Oasis HLB columns. PS-DVB, PBD-zirconia and Xterra RP 18 columns have been used in efficiency studies. It was found that simply elevating the column temperature did not increase the efficiency of a separation in superheated water chromatography. The efficiency depended on flow rate, injection volume and also mobile phase preheating system. Although high efficiencies were not achieved with superheated water on PS-DVB and Xterra RP 18 columns, a higher efficiency was achieved on a PBD-zirconia column with superheated water than with 25-35% ACN at room temperature. The proposed theoretical increases in uopt were measured on three columns using superheated water as the mobile phase. The application of the superheated water chromatographic method to the separation of the pungent constituents of ginger by superheated water chromatography-NMR coupling system was studied. The coupling of superheated water chromatography using deuterium oxide to NMR spectroscopy for the separation of dry ginger extract was successful, although the NMR sensitivity in on-line mode coupling system was low. However, four compounds were identified in the ginger extract by stop-flow mode on superheated water chromatography-UV-NMR detection system. (author)
Compressive Strength of Hydrostatic-Stress-Sensitive Materials at High Strain-Rates
Institute of Scientific and Technical Information of China (English)
LI Q M; LU Y B
2008-01-01
Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate.which have been included in material models to improve the reliability of numerical Simulations of the material and structural responses Under impact and biasl tcads,The strain-rate effects on the dynamic Compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated.It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects,which,as a non-strain-rate factor,may greatly enhance the compressive strength of these materials.Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials,and thus may over-estimate the structural resistance to impact and blast lgads.leading fo non-conservative design of protective structures.
Cai, Mingyi; Wu, Qingming; Liu, Xiande; Yao, Cuiluan; Chen, Qingkai; Wang, Zhiyong
2010-07-01
The present study investigated conditions for inducing mito-gynogenetic (endomitosis) diploids by hydrostatic pressure in the large yellow croaker Pseudosciaena crocea. In haploid control groups, the development of eggs was activated with ultraviolet radiated semen. All fry presented typical haploid syndrome in the haploid control groups, and were verified as haploids using cytometry. After hydrostatic pressure treatment, morphologically normal fry reappeared at different frequencies according to the intensity and time of pressure shock. Fry with normal appearance in the pressure treated groups were verified as gynogenetic double haploids (GDHs), containing only one allele from the female parent at all four diagnostic microsatellite loci. For a fixed duration of 3 min, the optimal intensity of blocking the first mitosis was determined to be 40 Mpa, which was similar to that of blocking the second meiosis. There was a “window” of starting time, from 36.1 min to 38.1 min post-insemination at 25.0±1.0°C, within which the production of GDHs was not significantly different. Maximum production of morphologically normal fries, 9.36%±2.97% of developed eggs, was found when the eggs were shocked with hydrostatic pressure at 40 Mpa for 3 min, starting from 38.1 min post insemination at 25.0±1.0°C.
Pollution Analysis of New Synthetic Biodegradable Fluid During Durab Ility Test of Hydrostatic Pump
Directory of Open Access Journals (Sweden)
Tulík Juraj
2014-03-01
Full Text Available This paper deals with the pollution evaluation of a biodegradable fluid, which was used as a working medium during the laboratory durability test of a hydrostatic pump. There was used a new synthetic biodegradable fluid MOL Farm UTTO Synt., developed and produced by MOL Group, Hungary. The fluid should have been practically used as a universal, common gear-hydraulic filling in agricultural machines. During the test, the pollution of used fluid was evaluated on the basis of cleanliness code, filtration of solid particles and ferrography. Based on results of cleanliness code, we could monitor the course of hydrostatic pump wear. After test completion, the fluid was subjected to filtration of solid particles and ferrography, where clusters of small particles and larger particles were detected. On the basis of their surface and shape, they were included in particles of adhesive wear. By the comparison method it was found that they are bronze particles located in the bearings of the hydrostatic pump used.
Praveen, K.; Rajiniganth, M. P.; Arun, A. D.; Sahoo, P.; Satya Murty, S. A. V.
2016-02-01
A novel approach towards deployment of a hydrostatic pressure based level monitoring device is presented for continuous monitoring of liquid level in a reservoir with high resolution and precision. Some of the major drawbacks such as spurious information of measured level due to change in ambient temperature, requirement of high resolution pressure sensor, and bubbling effect by passing air or any gaseous fluid into the liquid are overcome by using such a newly designed hydrostatic pressure based level monitoring device. The technique involves precise measurement of hydrostatic pressure exerted by the process liquid using a high sensitive pulsating-type differential pressure sensor (capacitive type differential pressure sensor using a specially designed oil manometer) and correlating it to the liquid level. In order to avoid strong influence of temperature on liquid level, a temperature compensation methodology is derived and used in the system. A wireless data acquisition feature has also been provided in the level monitoring device in order to work in a remote area such as a radioactive environment. At the outset, a prototype level measurement system for a 1 m tank is constructed and its test performance has been well studied. The precision, accuracy, resolution, uncertainty, sensitivity, and response time of the prototype level measurement system are found to be less than 1.1 mm in the entire range, 1%, 3 mm, <1%, 10 Hz/mm, and ˜4 s, respectively.
Pressure Decimation and Interpolation (PDI) method for a baroclinic non-hydrostatic model
Shi, Jian; Shi, Fengyan; Kirby, James T.; Ma, Gangfeng; Wu, Guoxiang; Tong, Chaofeng; Zheng, Jinhai
2015-12-01
Non-hydrostatic models are computationally expensive in simulating density flows and mass transport problems due to the requirement of sufficient grid resolution to resolve density and flow structures. Numerical tests based on the Non-Hydrostatic Wave Model, NHWAVE (Ma et al., 2012), indicated that up to 70% of the total computational cost may be born by the pressure Poisson solver in cases with high grid resolution in both vertical and horizontal directions. However, recent studies using Poisson solver-based non-hydrostatic models have shown that an accurate prediction of wave dispersion does not require a large number of vertical layers if the dynamic pressure is properly discretized. In this study, we explore the possibility that the solution for the dynamic pressure field may, in general, be decimated to a resolution far coarser than that used in representing velocities and other transported quantities, without sacrificing accuracy of solutions. Following van Reeuwijk (2002), we determine the dynamic pressure field by solving the Poisson equation on a coarser grid and then interpolate the pressure field onto a finer grid used for solving for the remaining dynamic variables. With the Pressure Decimation and Interpolation (PDI) method, computational efficiency is greatly improved. We use three test cases to demonstrate the model's accuracy and efficiency in modeling density flows.
TESTING STRICT HYDROSTATIC EQUILIBRIUM IN SIMULATED CLUSTERS OF GALAXIES: IMPLICATIONS FOR A1689
International Nuclear Information System (INIS)
Accurate mass determination of clusters of galaxies is crucial if they are to be used as cosmological probes. However, there are some discrepancies between cluster masses determined based on gravitational lensing and X-ray observations assuming strict hydrostatic equilibrium (i.e., the equilibrium gas pressure is provided entirely by thermal pressure). Cosmological simulations suggest that turbulent gas motions remaining from hierarchical structure formation may provide a significant contribution to the equilibrium pressure in clusters. We analyze a sample of massive clusters of galaxies drawn from high-resolution cosmological simulations and find a significant contribution (20%-45%) from non-thermal pressure near the center of relaxed clusters, and, in accord with previous studies, a minimum contribution at about 0.1 R vir, growing to about 30%-45% at the virial radius, R vir. Our results strongly suggest that relaxed clusters should have significant non-thermal support in their core region. As an example, we test the validity of strict hydrostatic equilibrium in the well-studied massive galaxy cluster A1689 using the latest high-resolution gravitational lensing and X-ray observations. We find a contribution of about 40% from non-thermal pressure within the core region of A1689, suggesting an alternate explanation for the mass discrepancy: the strict hydrostatic equilibrium is not valid in this region.
Praveen, K; Rajiniganth, M P; Arun, A D; Sahoo, P; Murty, S A V Satya
2016-02-01
A novel approach towards deployment of a hydrostatic pressure based level monitoring device is presented for continuous monitoring of liquid level in a reservoir with high resolution and precision. Some of the major drawbacks such as spurious information of measured level due to change in ambient temperature, requirement of high resolution pressure sensor, and bubbling effect by passing air or any gaseous fluid into the liquid are overcome by using such a newly designed hydrostatic pressure based level monitoring device. The technique involves precise measurement of hydrostatic pressure exerted by the process liquid using a high sensitive pulsating-type differential pressure sensor (capacitive type differential pressure sensor using a specially designed oil manometer) and correlating it to the liquid level. In order to avoid strong influence of temperature on liquid level, a temperature compensation methodology is derived and used in the system. A wireless data acquisition feature has also been provided in the level monitoring device in order to work in a remote area such as a radioactive environment. At the outset, a prototype level measurement system for a 1 m tank is constructed and its test performance has been well studied. The precision, accuracy, resolution, uncertainty, sensitivity, and response time of the prototype level measurement system are found to be less than 1.1 mm in the entire range, 1%, 3 mm, <1%, 10 Hz/mm, and ∼4 s, respectively. PMID:26931895
International Nuclear Information System (INIS)
Crushed natural rock salt is a primary candidate for use as backfill and barrier material at the Waste Isolation Pilot Plant (WIPP) and therefore Sandia National Laboratories (SNL) has been pursuing a laboratory program designed to quantify its consolidation properties and permeability. Variables that influence consolidation rate that have been examined include stress state and moisture content. The experimental results presented in this report complement existing studies and work in progress conducted by SNL. The experiments described in this report were designed to (1) measure permeabilities of consolidated specimens of crushed salt, (2) determine the influence of brine saturation on consolidation under hydrostatic loads, and 3) measure the effects of small applied shear stresses on consolidation properties. The laboratory effort consisted of 18 individual tests: three permeability tests conducted on specimens that had been consolidated at Sandia, six hydrostatic consolidation and permeability tests conducted on specimens of brine-saturated crushed WIPP salt, and nine shear consolidation and permeability tests performed on crushed WIPP salt specimens containing 3 percent brine by weight. For hydrostatic consolidation tests, pressures ranged from 1.72 MPa to 6.90 MPa. For the shear consolidation tests, confining pressures were between 3.45 MPa and 6.90 MPa and applied axial stress differences were between 0.69 and 4.14 MPa. All tests were run under drained conditions at 25 degrees C
Toxicity minimization of pipelines hydrostatic tests fluids, stage I: laboratory essays
Energy Technology Data Exchange (ETDEWEB)
Lacerda, Jorge A.S.; Penna, Monica de O.; Portela, Daniele B.; Christino, Fernando P.; Silva, Joao L.B. da; Geraldo, Lucia M.L. [Petroleo do Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Mota, Vanessa V.C. [Fundacao Gorceix, Ouro Preto, MG (Brazil); Cravo Junior, Walter [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)
2009-07-01
This paper presents the results of the laboratory essays stage of the project for toxicity minimization of pipelines hydrostatic tests fluids. The hydrostatic-hibernation fluid composition most used by PETROBRAS in offshore operations is seawater added with sodium bis sulfite, fluorescein, alquildimetilbenzilamonium chloride, and tetrakis-hydroxymethyl-phosphonium sulfate (THPS). In order to reduce the toxicity of the fluid used in hydrostatic tests, the use of lesser concentrations of THPS was attempted with UV radiation application as a disinfection technique prior to the adding of the fluid's components. The compositions were evaluated in different conditions of temperature use of UV radiation or not and oxygen scavenger adding (presence and absence). The fluids were kept hibernating for 120 days. All the parameters tested after hibernation were compared to fresh from preparation samples (zero time samples). The fluid's characteristics were evaluated by microbiological control and toxicity as well as the THPS residual. Results showed that the UV treatment was more effective in the absence of oxygen scavenger. The temperature acts as a microbial growth control agent, as expected. To large scale operations, a water quality monitoring must be performed previously to any field operations, in order to determinate the best treatment to be used in each case. (author)
Performance of a hydrostatic sampler for collecting samples at the water-sediment interface in lakes
Directory of Open Access Journals (Sweden)
Fernando PEDROZO
2008-02-01
Full Text Available The water-sediment interface plays a significant role in the determination of the trophic degree of a waterbody. Numerous redox reactions take place there, resulting in the release of contaminants from the sediments to the water column. The aim of the present work was to develop an equipment for collecting samples from the water-sediment interface. Such equipment was to have a simple design, low construction cost, no depth limitations, and high levels of personal safety and to be reliable in the collection of samples. The performance of the hydrostatic sampler thus developed was tested against samples collected either remotely with a corer or directly with syringes by autonomous divers. The hydrostatic sampler permits access to depths where the costs of the traditional diving methodology are expensive, and where working conditions are dangerous for the diver. The hydrostatic sampler provides an additional means of collecting samples from the water-sediment interface, which together with pore-water samples, facilitates the investigation and understanding of chemical mechanisms in lakes, for instance, those that control the P release from sediment to the water column.
Electronic amplifiers for automatic compensators
Polonnikov, D Ye
1965-01-01
Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as
Visser, H.A.; Wolters, M.; Bor, T.C.; Engels, T.A.P.; Govaert, L. E.
2008-01-01
Extruded polymer pipes are qualified using pressurized pipe tests. With these tests the long-term hydrostatic strength is determined by subjecting the pipes to an internal pressure, while measuring the time-to-failure. Although these tests can be accelerated (at higher temperatures), they remain time consuming and require a spacious experimental setup. To circumvent this costly method a model based approach is proposed by which the long-term hydrostatic strength is predicted. Using short term...
Clothes Dryer Automatic Termination Evaluation
Energy Technology Data Exchange (ETDEWEB)
TeGrotenhuis, Ward E.
2014-10-01
Volume 2: Improved Sensor and Control Designs Many residential clothes dryers on the market today provide automatic cycles that are intended to stop when the clothes are dry, as determined by the final remaining moisture content (RMC). However, testing of automatic termination cycles has shown that many dryers are susceptible to over-drying of loads, leading to excess energy consumption. In particular, tests performed using the DOE Test Procedure in Appendix D2 of 10 CFR 430 subpart B have shown that as much as 62% of the energy used in a cycle may be from over-drying. Volume 1 of this report shows an average of 20% excess energy from over-drying when running automatic cycles with various load compositions and dryer settings. Consequently, improving automatic termination sensors and algorithms has the potential for substantial energy savings in the U.S.
Prospects for de-automatization.
Kihlstrom, John F
2011-06-01
Research by Raz and his associates has repeatedly found that suggestions for hypnotic agnosia, administered to highly hypnotizable subjects, reduce or even eliminate Stroop interference. The present paper sought unsuccessfully to extend these findings to negative priming in the Stroop task. Nevertheless, the reduction of Stroop interference has broad theoretical implications, both for our understanding of automaticity and for the prospect of de-automatizing cognition in meditation and other altered states of consciousness. PMID:20356765
Process automatization in system administration
Petauer, Janja
2013-01-01
The aim of the thesis is to present automatization of user management in company Studio Moderna. The company has grown exponentially in recent years, that is why we needed to find faster, easier and cheaper way of man- aging user accounts. We automatized processes of creating, changing and removing user accounts within Active Directory. We prepared user interface inside of existing application, used Java Script for drop down menus, wrote script in scripting programming langu...
Automatic Number Plate Recognition System
Rajshree Dhruw; Dharmendra Roy
2014-01-01
Automatic Number Plate Recognition (ANPR) is a mass surveillance system that captures the image of vehicles and recognizes their license number. The objective is to design an efficient automatic authorized vehicle identification system by using the Indian vehicle number plate. In this paper we discus different methodology for number plate localization, character segmentation & recognition of the number plate. The system is mainly applicable for non standard Indian number plates by recognizing...
Eating as an Automatic Behavior
Deborah A. Cohen, MD, MPH; Thomas A. Farley, MD, MPH
2007-01-01
The continued growth of the obesity epidemic at a time when obesity is highly stigmatizing should make us question the assumption that, given the right information and motivation, people can successfully reduce their food intake over the long term. An alternative view is that eating is an automatic behavior over which the environment has more control than do individuals. Automatic behaviors are those that occur without awareness, are initiated without intention, tend to continue without contr...
Gyrokinetic modelling of stationary electron and impurity profiles in tokamaks
Skyman, Andreas; Tegnered, Daniel
2014-01-01
Particle transport due to Ion Temperature Gradient/Trapped Electron (ITG/TE) mode turbulence is investigated using the gyrokinetic code GENE. Both a reduced quasilinear (QL) treatment and nonlinear (NL) simulations are performed for typical tokamak parameters corresponding to ITG dominated turbulence. A selfconsistent treatment is used, where the stationary local profiles are calculated corresponding to zero particle flux simultaneously for electrons and trace impurities. The scaling of the stationary profiles with magnetic shear, safety factor, electron-to-ion temperature ratio, collisionality, toroidal sheared rotation, triangularity, and elongation is investigated. In addition, the effect of different main ion mass on the zero flux condition is discussed. The electron density gradient can significantly affect the stationary impurity profile scaling. It is therefore expected, that a selfconsistent treatment will yield results more comparable to experimental results for parameter scans where the stationary b...
STABLE STATIONARY STATES OF NON-LOCAL INTERACTION EQUATIONS
FELLNER, KLEMENS
2010-12-01
In this paper, we are interested in the large-time behaviour of a solution to a non-local interaction equation, where a density of particles/individuals evolves subject to an interaction potential and an external potential. It is known that for regular interaction potentials, stable stationary states of these equations are generically finite sums of Dirac masses. For a finite sum of Dirac masses, we give (i) a condition to be a stationary state, (ii) two necessary conditions of linear stability w.r.t. shifts and reallocations of individual Dirac masses, and (iii) show that these linear stability conditions imply local non-linear stability. Finally, we show that for regular repulsive interaction potential Wε converging to a singular repulsive interaction potential W, the Dirac-type stationary states ρ̄ ε approximate weakly a unique stationary state ρ̄ ∈ L∞. We illustrate our results with numerical examples. © 2010 World Scientific Publishing Company.
Stationary and translating configurations of point vortices in a plane
International Nuclear Information System (INIS)
The problem of constructing and classifying stationary and translating configurations of vortices in an inviscid incompressible fluid has been considered. All the configurations are given. Some of these configurations are new
Tunnelling effect of the non-stationary Kerr black hole
Institute of Scientific and Technical Information of China (English)
Yang Shu-Zheng; Chen De-You
2008-01-01
Extending Parikh and Wilezek's work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilton-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein-Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole.
Tunnelling effect of the non-stationary Kerr black hole
Yang, Shu-Zheng; Chen, De-You
2008-03-01
Extending Parikh and Wilczek's work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilton-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein-Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole.
Synoptic versus orographic control on stationary convective banding
Barrett, Andrew I.; Gray, Suzanne L; Kirshbaum, Daniel J.; Roberts, Nigel M.; Schultz, David M.; Fairman Jr, Jonathan G.
2015-01-01
Quasi-stationary convective bands can cause large localised rainfall accumulations and are often anchored by topographic features. Here, the predictability of and mechanisms causing one such band are determined using ensembles of the Met Office Unified Model at convection-permitting resolution (1.5 km grid length). The band was stationary over the UK for 3 h and produced rainfall accumulations of up to 34 mm. The amount and location of the predicted rainfall was highly variable despite only s...
Inference for local autocorrelations in locally stationary models
Zhao, Zhibiao
2014-01-01
For non-stationary processes, the time-varying correlation structure provides useful insights into the underlying model dynamics. We study estimation and inferences for local autocorrelation process in locally stationary time series. Our constructed simultaneous confidence band can be used to address important hypothesis testing problems, such as whether the local autocorrelation process is indeed time-varying and whether the local autocorrelation is zero. In particular, our result provides a...
Stationary bootstrapping realized volatility under market microstructure noise
Hwang, Eunju; Shin, Dong Wan
2013-01-01
Large-sample validity is proved for stationary bootstrapping of a bias-corrected realized volatility under market microstructure noise, which enables us to construct a bootstrap confidence interval of integrated volatility. A finite-sample simulation shows that the stationary bootstrapping confidence interval outperforms existing ones which are constructed ignoring market microstructure noise or using asymptotic normality for the bias-corrected realized volatility.
Quasi-Stationary Distributions for Models of Heterogeneous Catalysis
de Oliveira, Marcelo M.; Dickman, Ronald
2004-01-01
We construct the quasi-stationary (QS) distribution for two models of heterogeneous catalysis having two absorbing states: the ZGB model for the oxidation of CO, and a version with noninstantaneous reactions. Using a mean-field-like approximation, we study the quasi-stationary surface coverages, moment ratios and the lifetime of the QS state. We also derive an improved, consistent one-site mean-field theory for the ZGB model.
Certain Periodically Correlated Multi-component Locally Stationary Processes
Modarresi, N .; Rezakhah, S.
2010-01-01
By introducing $X^{ls}(t)$ as a random mixture of two stationary processes where the time dependent random weights have exponentially convex covariance, we show that this process has a multi-component locally stationary covariance function in Silverman's sense. We also define $X^p(t)$ as a certain continuous time periodically correlated (PC) process where its covariance function is generated by the covariance function of a discrete time through defining some simple random measure on real line...
Locally stationary factor models : identification and nonparametric estimation
Motta, Giovanni; Hafner, Christian; Von Sachs, Rainer
2006-01-01
In this paper we propose a new approximate factor model for large cross-section and time dimensions. Factor loadings are assumed to be smooth functions of time, which allows to consider the model as locally stationary while permitting empirically observed time-varying second moments. Factor loadings are estimated by the eigenvectors of a nonparametrically estimated covariance matrix. As is well-known in the stationary case, this principal com- ponents estimator is consistent in approximate fa...
Measuring correlations between non-stationary series with DCCA coefficient
Kristoufek, Ladislav
2014-05-01
In this short report, we investigate the ability of the DCCA coefficient to measure correlation level between non-stationary series. Based on a wide Monte Carlo simulation study, we show that the DCCA coefficient can estimate the correlation coefficient accurately regardless the strength of non-stationarity (measured by the fractional differencing parameter d). For a comparison, we also report the results for the standard Pearson correlation coefficient. The DCCA coefficient dominates the Pearson coefficient for non-stationary series.
Similarity flows between a rotating and a stationary disk
International Nuclear Information System (INIS)
The radial distribution of fluid pressure on a stationary disk coaxial with a rotating disk is determined experimentally for various inter-disc spacings. The results show that similarity flows are only possible for both small and large values of this distance. In the former case, the flow faraway from the stationary disk appears to be that suggested by Batchelor, while in the latter case, the flow turns out to be in accordance with the assumption of Stewartson. (Author)
Central limit theorem for Fourier transform of stationary processes
Peligrad, Magda
2009-01-01
We consider asymptotic behavior of Fourier transforms of stationary ergodic sequences with finite second moments. We establish the central limit theorem (CLT) for almost all frequencies and also the annealed CLT. The theorems hold for all regular sequences. Our results shed new light on the foundation of spectral analysis and on the asymptotic distribution of periodogram, and it provides a nice blend of harmonic analysis, theory of stationary processes and theory of martingales.
Stationary growth and unique invariant harmonic measure of cylindrical DLA
Marchetti, Riccardo; Taloni, Alessandro; Caglioti, Emanuele; Loreto, Vittorio; Pietronero, Luciano
2013-01-01
We prove that the harmonic measure is stationary, unique and invariant on the interface of DLA growing on a cylinder surface. We provide a detailed theoretical analysis puzzling together multiscaling, multifractality and conformal invariance, supported by extensive numerical simulations of clusters built using conformal mappings and on lattice. The growth properties of the active and frozen zones are clearly elucidated. We show that the unique scaling exponent characterizing the stationary gr...
Novel stationary phases based on asphaltenes for gas chromatography.
Boczkaj, Grzegorz; Momotko, Malwina; Chruszczyk, Dorota; Przyjazny, Andrzej; Kamiński, Marian
2016-07-01
We present the results of investigations on the possibility of the application of the asphaltene fraction isolated from the oxidized residue from vacuum distillation of crude oil as a stationary phase for gas chromatography. The results of the investigation revealed that the asphaltene stationary phases can find use for the separation of a wide range of volatile organic compounds. The experimental values of Rohrschneider/McReynolds constants characterize the asphaltenes as stationary phases of medium polarity and selectivity similar to commercially available phases based on alkyl phthalates. Isolation of asphaltenes from the material obtained under controlled process conditions allows the production of a stationary phase having reproducible sorption properties and chromatographic columns having the same selectivity. Unique selectivity and high thermal stability make asphaltenes attractive as a material for stationary phases for gas chromatography. A low production cost from a readily available raw material (oxidized petroleum bitumens) is an important economic factor in case of application of the asphaltene stationary phases for preparative and process separations. PMID:27144876
International Nuclear Information System (INIS)
This work is concerned with the theoretical study of the combined effects of applied electric field and hydrostatic pressure on the binding energy and impurity polarizability of a donor impurity in laterally coupled double InAs/GaAs quantum-well wires. calculations have been made in the effective mass and parabolic band approximations and using a variational method. The results are reported for different configurations of wire and barriers widths, impurity position, and electric field and hydrostatic pressure strengths. Our results show that for symmetrical structures the binding energy is an even function of the impurity position along the growth direction of the structure. Also, we found that for hydrostatic pressure strength up to 38 kbar, the binding energy increases linearly with hydrostatic pressure, while for larger values of hydrostatic pressure the binding energy has a nonlinear behavior. Finally, we found that the hydrostatic pressure can increase the coupling between the two parallel quantum well wires.
Automatic Bandwidth Adjustment for Content Distribution in MPLS Networks
Directory of Open Access Journals (Sweden)
D. Moltchanov
2008-04-01
Full Text Available Aggregates of real-time traffic may experience changes in their statistical characteristics often manifesting non stationary behavior. In multi protocol label switching (MPLS networks this type of the traffic is assigned constant amount of resources. This may result in ineffective usage of resources when the load is below than expected or inappropriate performance when the load is higher. In this paper we propose new algorithm for dynamic resource adaptation to temporarily changing traffic conditions. Assuming that network nodes may reallocate resources on-demand using automatic bandwidth adjustment capability of MPLS framework, the proposed algorithm, implemented at ingress MPLS nodes, dynamically decides which amount of resources is currently sufficient to handle arriving traffic with given performance metrics. This decision is then communicated to interior MPLS nodes along the label switched path. As a basic tool of the algorithm we use change-point statistical test that signals time instants at which statistical characteristics of traffic aggregates change. The major advantage of the proposed approach is that it is fully autonomous, that is, network nodes do not need any support from hosts in terms of resource reservation requests. The proposed algorithm is well suited for traffic patterns experiencing high variability, especially, for non stationary type of the traffic.
International Nuclear Information System (INIS)
The project involves the development and industrial operation of a versatile, stationary automatic foam spraying device, SAMIDIN, for chemical decontamination of pipes measuring 0.5 to 1.6 m in diameter and 2 to 3.5 m long. Decontamination is obtained by successive automatic spraying cycles with alkaline and acid foams, and by high pressure water rinsing. Industrial utilization of a device of this type for decommissioning purposes would limit the occupational exposure hazard inside or in contact with contaminated pipes while minimizing the quantity of liquid wastes produced
Reversible Morphological Control of Tubulin-Encapsulating Giant Liposomes by Hydrostatic Pressure.
Hayashi, Masahito; Nishiyama, Masayoshi; Kazayama, Yuki; Toyota, Taro; Harada, Yoshie; Takiguchi, Kingo
2016-04-19
Liposomes encapsulating cytoskeletons have drawn much recent attention to develop an artificial cell-like chemical-machinery; however, as far as we know, there has been no report showing isothermally reversible morphological changes of liposomes containing cytoskeletons because the sets of various regulatory factors, that is, their interacting proteins, are required to control the state of every reaction system of cytoskeletons. Here we focused on hydrostatic pressure to control the polymerization state of microtubules (MTs) within cell-sized giant liposomes (diameters ∼10 μm). MT is the cytoskeleton formed by the polymerization of tubulin, and cytoskeletal systems consisting of MTs are very dynamic and play many important roles in living cells, such as the morphogenesis of nerve cells and formation of the spindle apparatus during mitosis. Using real-time imaging with a high-pressure microscope, we examined the effects of hydrostatic pressure on the morphology of tubulin-encapsulating giant liposomes. At ambient pressure (0.1 MPa), many liposomes formed protrusions due to tubulin polymerization within them. When high pressure (60 MPa) was applied, the protrusions shrank within several tens of seconds. This process was repeatedly inducible (around three times), and after the pressure was released, the protrusions regenerated within several minutes. These deformation rates of the liposomes are close to the velocities of migrating or shape-changing living cells rather than the shortening and elongation rates of the single MTs, which have been previously measured. These results demonstrate that the elongation and shortening of protrusions of giant liposomes is repeatedly controllable by regulating the polymerization state of MTs within them by applying and releasing hydrostatic pressure. PMID:27023063
40 CFR 60.4305 - Does this subpart apply to my stationary combustion turbine?
2010-07-01
... stationary combustion turbine? 60.4305 Section 60.4305 Protection of Environment ENVIRONMENTAL PROTECTION... of Performance for Stationary Combustion Turbines Applicability § 60.4305 Does this subpart apply to my stationary combustion turbine? (a) If you are the owner or operator of a stationary...
International Nuclear Information System (INIS)
Particle accelerators require very tight tolerances on the alignment and stability of their elements: magnets, accelerating cavities, vacuum chambers, etc. In this article we describe the Hydrostatic Level Sensors (HLS) for very low frequency measurements used in a variety of facilities at Fermilab. We present design features of the sensors, outline their technical parameters, describe their test and calibration procedures, discuss different regimes of operation and give few illustrative examples of the experimental data. Detail experimental results of the ground motion measurements with these detectors will be presented in subsequent papers.
International Nuclear Information System (INIS)
Particle accelerators require very tight tolerances on the alignment and stability of their elements: magnets, accelerating cavities, vacuum chambers, etc. In this article we describe the Hydrostatic Level Sensors (HLS) for very low frequency measurements used in a variety of facilities at Fermilab. We present design features of the sensors, outline their technical parameters, describe their test and calibration procedures, discuss different regimes of operation and give few illustrative examples of the experimental data. Detail experimental results of the ground motion measurements with these detectors will be presented in subsequent papers.
Wu, Huijuan; Sun, Zhenshi; Qian, Ya; Zhang, Tao; Rao, Yunjiang
2015-07-01
A hydrostatic leak test for water pipeline with a distributed optical fiber vibration sensing (DOVS) system based on the phase-sensitive OTDR technology is studied in this paper. By monitoring one end of a common communication optical fiber cable, which is laid in the inner wall of the pipe, we can detect and locate the water leakages easily. Different apertures under different pressures are tested and it shows that the DOVS has good responses when the aperture is equal or larger than 4 mm and the inner pressure reaches 0.2 Mpa for a steel pipe with DN 91cm×EN 2cm.
Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.
2007-01-01
Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.
Ductility response of three high-temperature materials tested under hydrostatic pressure
International Nuclear Information System (INIS)
The pressure-ductility response of Udimet 700, TZM Mo, and Stellite 21 was determined using a Bridgman-Birch hydrostatic pressure system. Reduction in area (RA) for Udimet 700 increased linearly from 20 to 75 percent over a 0 to 25 x 108 N/m2 pressure range. For TZM Mo, RA increased from 60 percent to a limiting value of approximately 95 percent at 109 N/m2. Results for Stellite 21 were erratic and showed no general pressure dependence. Photomicrographs of the deformed materials are given and microstructures are related to deformation behavior
The hydrostatic equilibrium and its implications on the mechanical properties of planets
Directory of Open Access Journals (Sweden)
M. CAPUTO
1974-06-01
Full Text Available Under the hypothesis of hydrostatic equilibrium the planets of the solar system are represented on the plane (J"2, w2 a?/MG (J2 = second term of the gravitational potential, w = rotation rate of the planet, a — equatorial radius, M — mass of the planet, G = gravitational constant. Since the points representing the planets lie on a straight line it is possible to obtain informations on the giration moment and the moment of inertia of Uranus and Pluto.
DEFF Research Database (Denmark)
Guerinel, Matthieu; Zurkinden, Andrew Stephen; Alves, Marco;
2013-01-01
laboratory of Aalborg University. The device is a prototype of a singleWavestar float, scaled at 1:20, considering one degree of freedom only. The tests included a various range of incoming waves, from small regular waves to storm conditions irregular waves. The numerical simulations have been performed at...... the WavEC using an in-house time-domain model. The code, based on the linear potential theory, solves the system of motion equations using state-space representations of the radiation terms and includes nonlinear hydrostatic forces and nonlinear Froude-Krylov excitation terms, which require the...
Li, Xiu-Xia; Tian, Xin; Li, Jian-Rong
2016-06-01
Using thermal processing (TP) treatment (100 ℃, 1-8 min) as a control, the effects of high hydrostatic pressure (HHP, 200-500 MPa, 2.5-20 min) on the microbiological and biochemical characteristics of white shrimp Litopenaeus vannamei were investigated. The results showed that the efficiency of polyphenol oxidase (PPO) inactivation and log reduction of total plate count (TPC) by HHP treatment were all significantly lower than by TP treatment (p treatment was significantly lower than with TP treatment (p treatment turned the appearance of shrimps slightly pink. PMID:26199222
Lin, L. A. G.; Liu, A. Q.; Yu, Y. F.; Zhang, C.; Lim, C. S.; Ng, S. H.; Yap, P. H.; Gao, H. J.
2008-06-01
A micro-optical-fluidic system (MOFS), which integrates a force generating device and an optical detector, is designed to measure the bulk modulus of a single living cell in real time under a controlled hydrostatic pressure. In this design, the accuracy of the bulk modulus measurement is improved because neither the force generating device nor the optical detector needs to be in contact with the cells. The MOFS device has been used to investigate the mechanotransduction of THP-1 human acute monocytic leukemia cells and the effects of the toxin lipopolysaccharide and colchicine on various properties of these cells.
International Nuclear Information System (INIS)
By means of hydrostatic pressure tuning, we have observed the strong-coupling exciton-polariton mode in a planar microcavity with an InGaAs/GaAs quantum well embedded in it, over a pressure range from 0.37 to 0.41 GPa. The experimental data can be fitted very well to a corresponding theoretical formula with a unique value of the vacuum Rabi splitting equal to 6.0 meV. A comparison between pressure tuning and other tuning methods is made as regards to what extent the intrinsic features of the exciton and cavity will be influenced during the tuning procedure. (author)
Energy Technology Data Exchange (ETDEWEB)
Zhang Jidong; Zhang Hao; Chen Jinghao; Deng Yuanming; Hu Chengyong; An Long; Yang Fuhua; Li Guohua; Zheng Houzhi [National Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing (China)
2002-06-03
By means of hydrostatic pressure tuning, we have observed the strong-coupling exciton-polariton mode in a planar microcavity with an InGaAs/GaAs quantum well embedded in it, over a pressure range from 0.37 to 0.41 GPa. The experimental data can be fitted very well to a corresponding theoretical formula with a unique value of the vacuum Rabi splitting equal to 6.0 meV. A comparison between pressure tuning and other tuning methods is made as regards to what extent the intrinsic features of the exciton and cavity will be influenced during the tuning procedure. (author)
Effects of high hydrostatic pressure on microflora and some quality attributes of grape juice
Mert, Mecnun; Buzrul, Sencer; Alpas, Hami
2013-03-01
Red and white grape juices were treated with high hydrostatic pressure (HHP) at three different pressures, temperature and time values to investigate the effects of HHP on natural microflora and some quality attributes of the juices. Increased pressure, temperature and time showed significant effect on the microbial reduction and no microbial growth were observed in HHP-treated grape juices up to 90 days. HHP had little or no effect on pH and color of the juices. Although 5-hydroxymethylfurfural (HMF) formation was observed in heat pasteurized samples, no HMF was detected in HHP-treated juices. This study demonstrated that HHP could be used as an alternative to heat treatment.
Effect of bulk modulus on performance of a hydrostatic transmission control system
Indian Academy of Sciences (India)
Ali Volkan Akkaya
2006-10-01
In this paper, we examine the performance of PID (proportional integral derivative) and fuzzy controllers on the angular velocity of a hydrostatic transmission system by means of Matlab-Simulink. A very novel aspect is that it includes the analysis of the effect of bulk modulus on system control. Simulation results demonstrates that bulk modulus should be considered as a variable parameter to obtain a more realistic model. Additionally, a PID controller is insufﬁcient in presence of variable bulk modulus, whereas a fuzzy controller provides robust angular velocity control.
Influence of layer waviness on the hydrostatic response of thick composite cylinders
Timothy L Brown
1992-01-01
The influence of layer waviness in thick cross-ply composite cylinders subjected to hydrostatic pressure is investigated. The cylinders considered are graphite-epoxy with a 2: 1 ratio of circumferential to axial layers. All cylinders considered contain 104 total layers with a layup of [90/(90/0/90h71s, where a '0° 1 layer is taken to be in the axial direction. The influence of a single isolated group of wavy layers in an otherwise perfect cylinder is evaluated. Layer waviness in only the c...
Directory of Open Access Journals (Sweden)
Xiaohong Liu
2013-12-01
Full Text Available Purpose: To investigate the effects of MTP-131 on trabeculum cells cultured under hydrostatic pressure Methods: Glaucomatous human trabecular meshwork (GTM3 cells were divided into three groups: the MTP-131 group, the hydrostatic group, and the normal group. The MTP-131 group was pretreated with 1 µM MTP-131, and the cells were then cultured under 80 mmHg pressure for 24 hours. The normal group was cultured under normal atmospheric pressure for 24 h, and the hydrostatic group was cultured under 80 mmHg pressure for 24 h. The change in the mitochondrial membrane potential the generation of reactive oxygen species (ROS and the release of cytochrome c from the mitochondria were analyzed with confocal microscopy. The generation of ROS and apoptosis were detected by flow cytometry. The expression of caspase-3 was detected by western blot analysis. Results: In GTM3 cells, culturing under hydrostatic pressure resulted in a decrease in the mitochondrial membrane potential, an elevation of intracellular ROS and a release of cytochrome c from the mitochondria. Pretreatment with MTP-131 prevented the mitochondrial depolarization, decreased the intracellular ROS, prohibited the release of cytochrome c from the mitochondria and inhibited apoptosis. The path of apoptosis is caspase-3 independent. Conclusion: MTP-131 can protect cultured trabecular cells from the damage caused by hydrostatic pressure.
Annual review in automatic programming
Goodman, Richard
2014-01-01
Annual Review in Automatic Programming focuses on the techniques of automatic programming used with digital computers. Topics covered range from the design of machine-independent programming languages to the use of recursive procedures in ALGOL 60. A multi-pass translation scheme for ALGOL 60 is described, along with some commercial source languages. The structure and use of the syntax-directed compiler is also considered.Comprised of 12 chapters, this volume begins with a discussion on the basic ideas involved in the description of a computing process as a program for a computer, expressed in
Bazin, C.; Vilinga, J.; Wittich, R.; Koutchmy, S.; Mouette, J.; Nitschelm, C.
2015-12-01
We present some new accurate CCD photometry analysis of the white light solar corona at the time of the last 20 March 2015 total eclipse (airborne observations on a Falcon 7X and at ground-based- Svalbard). We measured coronal brightness profiles taken along radial directions from 1.001 to 3 solar radii in the northern, southern and equatorial regions, after removing the F-corona and the sky background. These studies allow to evaluate the density gradients, structures and temperature heterogeneity, by considering the Thomson scattering in white light of the K- corona and also emissions of the EUV Fe XII 193A (1 to 2 MK) and Fe XI 171/174 (lower temperature) simultaneously observed by SDO/AIA and SWAP/Proba2 space missions. Some dispersion between the regions is noticed. The limitation of the hydrostatic equilibrium assumption in the solar atmosphere is discussed as well as the contribution of the magnetic field pressure gradients as illustrated by a comparison with the model stationary magnetic corona from Predictive Sc. Inc. These results are compared with the results of the quieter 2010 total solar eclipse corona analyzed with the same method. This photometric analysis of the inner and intermediate white light corona will contribute to the preparation of the Aspiics/Proba 3 flying formation future coronagraphic mission of ESA for new investigation at time of artificial eclipses produced in Space. Note that Aspiics will also observe in the He I D3 line at 5876 A, and will record intensities of the Fe XIV line 5303A simultaneously with the analysis of the orange white- light continuum, including precise polarimetry analysis. .
Simulation of non-stationary ground motion processes (I)
Institute of Scientific and Technical Information of China (English)
LIANG Jian-wen
2005-01-01
This paper presents a spectral representation method for simulation of non-stationary ground motion processes on the basis of Priestley's evolutionary spectral theory. Following this method, sample processes can be generated using a cosine series formula. It is shown that, these sample processes accurately reflect the prescribed characteristics of the evolutionary power spectral density function when the number of the terms in the cosine series is large enough; and the ensemble expected value and the ensemble autocorrelation function approach the corresponding target functions, respectively, as the sample size increases; and these sample processes are asymptotically normal as the number of the terms in the series tends to infinity. Finally, a few special cases of the formula are discussed, one of which is non-stationary white noise process, and other one is reduced to the formula for simulation of stationary stochastic processes.
Non-Stationary Dependence Structures for Spatial Extremes
Huser, Raphaël
2016-03-03
Max-stable processes are natural models for spatial extremes because they provide suitable asymptotic approximations to the distribution of maxima of random fields. In the recent past, several parametric families of stationary max-stable models have been developed, and fitted to various types of data. However, a recurrent problem is the modeling of non-stationarity. In this paper, we develop non-stationary max-stable dependence structures in which covariates can be easily incorporated. Inference is performed using pairwise likelihoods, and its performance is assessed by an extensive simulation study based on a non-stationary locally isotropic extremal t model. Evidence that unknown parameters are well estimated is provided, and estimation of spatial return level curves is discussed. The methodology is demonstrated with temperature maxima recorded over a complex topography. Models are shown to satisfactorily capture extremal dependence.
Non-Stationary Internal Tides Observed with Satellite Altimetry
Ray, Richard D.; Zaron, E. D.
2011-01-01
Temporal variability of the internal tide is inferred from a 17-year combined record of Topex/Poseidon and Jason satellite altimeters. A global sampling of along-track sea-surface height wavenumber spectra finds that non-stationary variance is generally 25% or less of the average variance at wavenumbers characteristic of mode-l tidal internal waves. With some exceptions the non-stationary variance does not exceed 0.25 sq cm. The mode-2 signal, where detectable, contains a larger fraction of non-stationary variance, typically 50% or more. Temporal subsetting of the data reveals interannual variability barely significant compared with tidal estimation error from 3-year records. Comparison of summer vs. winter conditions shows only one region of noteworthy seasonal changes, the northern South China Sea. Implications for the anticipated SWOT altimeter mission are briefly discussed.
Simulation of non-stationary ground motion processes (II)
Institute of Scientific and Technical Information of China (English)
LIANG Jian-wen
2005-01-01
This paper proposes a method for simulation of non-stationary ground motion processes having the identical statistical feature, time-dependent power spectrum, with a given ground motion record, on the basis of review of simulation of non-stationary ground motion processes. The method has the following advantages: the sample processes are non-stationary both in amplitude and frequency, and both the amplitude and frequency non-stationarity depend on the target power spectrum; the power spectrum of any sample process does not necessarily accord with the target power spectrum, but statistically, it strictly accords with the target power spectrum. Finally, the method is verified by simulation of one acceleration record in Landers earthquake.
Verma, Suresh; Kumar, Vijay; Gupta, Kapil Dev
2016-01-01
This paper presents a theoretical study of the effects of bearing shell deformation upon the performance characteristics of a capillary compensated multi-recess hydrostatic journal bearing system operating with micropolar lubricant. The finite element method has been used to solve the modified Reynolds' equation governing the micropolar lubricant flow in the bearing and the three dimensional elasticity equations governing the displacement field in the bearing shell. The elasto-hydrostatic performance characteristics of the bearing are presented for various values of micropolar parameters ( l m and N 2) and for a wide range of the deformation coefficient bar{C}d which takes into account the flexibility of the bearing shell. The computed results indicate that the influence of the bearing shell flexibility is quite significant on the performance characteristics of recessed hydrostatic journal bearing system operating with micropolar lubricant.
International Nuclear Information System (INIS)
Attempt was made to determine the influence of hydrostatic pressure on the properties of the alloy VT1-0 at cryogenic temperatures both under straining of the alloy and without it. Hardening of the material is observed only in that part of the specimen, which experienced a deformation, while the very exposure of the alloy under hydrostatic pressure does not lead to strengthening of the material. At the same time, measurements of acoustic emission (AE) show that in the near-surface layers the forces of hydrostatic compression alone, i.e. without a deformation, cause some changes in the structure, which stipulate an increase of the energy and (to a lesser extent) of the median frequency of AE signals. An explanation of this phenomenon is suggested
Institute of Scientific and Technical Information of China (English)
ZHAO Ming; HUANG Zhengdong; LI Bin; CHEN Liping
2007-01-01
Aiming at the approximate error of commonly used methods on calculation of hydrostatic pressures of closed hydrostatic guideways with multiple pockets, a more accurate solution is proposed. Taking design of beam & slide-rest guideways for a heavy duty CNC vertical turning mill as an example, under an assumption that stiffnesses of guideways and their jointing structure are sufficiently large, the pressures of the pockets can be attained by adding a co-planarity equation that con strains pocket centers. Then, an optimization model is built to minimize the highest pocket pressure under additional constraints that are posed on the highest seal margin pressure, the highest levitating pressure of the pockets, and the maximum deformation of the guideways. The optimization problem is solved sequentially by using the methods of design of experiments and adaptive simulated annealing on iSIGHT software platform. The results show significant improvements to the original design. Optimized maximum hydrostatic pressure meets the requirement of hydraulic system.
Commercon, Benoit; Dullemond, Cornelis P; Henning, Thomas
2012-01-01
The low-mass star formation evolutionary sequence is relatively well-defined both from observations and theoretical considerations. The first hydrostatic core is the first protostellar equilibrium object that is formed during the star formation process. Using state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations, we aim to provide predictions for the dust continuum emission from first hydrostatic cores. We investigate the collapse and the fragmentation of magnetized one solar mass prestellar dense cores and the formation and evolution of first hydrostatic cores using the RAMSES code. We use three different magnetization levels for the initial conditions, which cover a large variety of early evolutionary morphology, e.g., the formation of a disk or a pseudo-disk, outflow launching, and fragmentation. We post-process the dynamical calculations using the 3D radiative transfer code RADMC-3D. We compute spectral energy distributions and usual evolutionary stage indicators such as...
Non-stationary extreme models and a climatic application
Directory of Open Access Journals (Sweden)
M. Nogaj
2007-06-01
Full Text Available In this paper, we study extreme values of non-stationary climatic phenomena. In the usually considered stationary case, the modelling of extremes is only based on the behaviour of the tails of the distribution of the remainder of the data set. In the non-stationary case though, it seems reasonable to assume that the temporal dynamics of the entire data set and that of extremes are closely related and thus all the available information about this link should be used in statistical studies of these events. We try to study how centered and normalized data which are closer to stationary data than the observation allows easier statistical analysis and to understand if we are very far from a hypothesis stating that the extreme events of centered and normed data follow a stationary distribution. The location and scale parameters used for this transformation (the central field, as well as extreme parameters obtained for the transformed data enable us to retrieve the trends in extreme events of the initial data set. Through non-parametric statistical methods, we thus compare a model directly built on the extreme events and a model reconstructed from estimations of the trends of the location and scale parameters of the entire data set and stationary extremes obtained from the centered and normed data set. In case of a correct reconstruction, we can clearly state that variations of the characteristics of extremes are well explained by the central field. Through these analyses we bring arguments to choose constant shape parameters of extreme distributions. We show that for the frequency of the moments of high threshold excesses (or for the mean of annual extremes, the general dynamics explains a large part of the trends on frequency of extreme events. The conclusion is less obvious for the amplitudes of threshold exceedances (or the variance of annual extremes – especially for cold temperatures, partly justified by the statistical tools used, which
Non-Hydrostatic Modelling of Waves and Currents over Subtle Bathymetric Features
Gomes, E.; Mulligan, R. P.; McNinch, J.
2014-12-01
Localized areas with high rates of shoreline erosion on beaches, referred to as erosional hotspots, can occur near clusters of relict shore-oblique sandbars. Wave transformation and wave-driven currents over these morphological features could provide an understanding of the hydrodynamic-morphologic coupling mechanism that connects them to the occurrence of erosional hotspots. To investigate this, we use the non-hydrostatic SWASH model that phase-resolves the free surface and fluid motions throughout the water column, allowing for high resolution of wave propagation and breaking processes. In this study we apply a coupled system of nested models including SWAN over a large domain of the North Carolina shelf with smaller nested SWASH domains in areas of interest to determine the hydrodynamic processes occurring over shore oblique bars. In this presentation we focus on a high resolution grid (10 vertical layers, 10 m horizontal resolution) applied to the Duck region with model validation from acoustic wave and current data, and observations from the Coastal Lidar And Radar Imaging System (CLARIS). By altering the bathymetry input for each model run based on bathymetric surveys and comparing the predicted and observed wave heights and current profiles, the effects of subtle bathymetric perturbations have on wave refraction, wave breaking, surf zone currents and vorticity are investigated. The ability to predict wave breaking and hydrodynamics with a non-hydrostatic model may improve our understanding of surf zone dynamics in relation to morphologic conditions.
Changes in Chlorophyll Fluorescence of Rice Mutants Induced by High Hydrostatic Pressure
Institute of Scientific and Technical Information of China (English)
BAI; Cheng-ke; LI; Gui-shuang; PENG; Chang-lian; DUAN; Jun
2003-01-01
Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluorescence during different growth stages. In all the three mutants, the function of PSⅡ was improved, Fy/Fm ratio of mutants increased compared to their parent at tillering and heading stage, and φPS Ⅱ also improved except for Mutant 2 at heading stage. Similar to their parent, the mutants exhibited slight photoinhibition at noon and almost complete recovery to initial levels of 6:00 after 18:00 at heading stage. At milking stage, the photoinhibition in the mutants was obvious, and recovered rapidly compared to the parent. Yields of individual plant and grain/straw ratio were also higher in three mutants than the parent. Results indicated that characteristics of chlorophyll fluorescence in leaves of mutants and their photoinhibition in the field had changed. It is suggested that high hydrostatic pressure induction could be applied as a new effective approach in high-yield rice breeding in the future.
Directory of Open Access Journals (Sweden)
Chong-Tai Kim
2014-12-01
Full Text Available Chondroitin sulphate (CS, a major glycosaminoglycan, is an essential component of the extracellular matrix in cartilaginous tissues. Wapiti velvet antlers are a rich source of these molecules. The purpose of the present study was to develop an effective isolation procedure of CS from fresh velvet antlers using a combination of high hydrostatic pressure (100 MPa and enzymatic hydrolysis (papain. High CS extractability (95.1 ± 2.5% of total uronic acid was obtained following incubation (4 h at 50 °C with papain at pH 6.0 in 100 MPa compared to low extractability (19 ± 1.1% in ambient pressure (0.1 MPa. Antler CS fractions were isolated by Sephacryl S-300 chromatography and identified by western blot using an anti-CS monoclonal antibody. The antler CS fraction did not aggregate with hyaluronic acid in CL-2B chromatography and possessed DPPH radical scavenging activity at 78.3 ± 1.5%. The results indicated that high hydrostatic pressure and enzymatic hydrolysis procedure may be a useful tool for the isolation of CS from antler cartilaginous tissues.
The effect of hydrostatic vs. shock pressure treatment of plant seeds
International Nuclear Information System (INIS)
The hydrostatic pressure and shock response of plant seeds has been investigated antecedently, primarily driven by interest in reducing bacterial contamination of crops and the theory of panspermia, respectively. However, comparisons have not previously been made between these two methods ofapplying pressure to plant seeds. Here such a comparison has been undertaken based on the premise that any correlations in collected data may provide a route to inform understanding of damage mechanisms in the seeds under test. In this work two varieties of plant seeds were subjected to hydrostatic pressure via a non-end-loaded piston cylinder setup and shock compression via employment of a 50 mm bore, single stage gas gun using the flyer plate technique. Results from germination tests of recovered seed samples have been compared and contrasted, and initial conclusions made regarding causes of trends in the resultant data-set. Data collected has shown that cress seeds are extremely resilient to static loading, whereas the difference in the two forms of loading is negligible for lettuce seeds. Germination time has been seen to extend dramatically following static loading of cress seeds to greater than 0.4 GPa. In addition, the cut-off pressure previously seen to cause 0% germination in dynamic experiments performed on cress seeds has now also been seen in lettuce seeds.
Hydrostatic Simulation of Earth's Atmospheric Gas Using Multi-particle Collision Dynamics
Pattisahusiwa, Asis; Purqon, Acep; Viridi, Sparisoma
2016-01-01
Multi-particle collision dynamics (MPCD) is a mesoscopic simulation method to simulate fluid particle-like flows. MPCD has been widely used to simulate various problems in condensed matter. In this study, hydrostatic behavior of gas in the Earth's atmospheric layer is simulated by using MPCD method. The simulation is carried out by assuming the system under ideal state and is affected only by gravitational force. Gas particles are homogeneous and placed in 2D box. Interaction of the particles with the box is applied through implementation of boundary conditions (BC). Periodic BC is applied on the left and the right side, specular reflection on the top side, while bounce-back on the bottom side. Simulation program is executed in Arch Linux and running in notebook with processor Intel i5 @2700 MHz with 10 GB DDR3 RAM. The results show behaviors of the particles obey kinetic theory for ideal gas when gravitational acceleration value is proportional to the particle mass. Density distribution as a function of altitude also meets atmosphere's hydrostatic theory.
Effect of hydrostatic pressure on Yb(Rh1-xFex)2Si2
International Nuclear Information System (INIS)
The temperature scale, T*(K), in undoped YbRh2Si2 have gathered much attention due to its different interpretations. Substituting Fe on the Rh site in YbRh2Si2 causes a combined effect of chemical pressure and hole doping. By increasing Fe-doping, both the Kondo temperature and Neel temperature TN (= 70 mK for x = 0) decrease, with a critical concentration of x ∝ 0.08, which suppresses TN to zero. Since positive pressure enhances TN in Yb-based materials, the hole doping is most likely responsible for the supression. Along with the suppression of TN, T*(K) also decreases with Fe-doping and dissappears around the same critical concentration, x = 0.08. Application of hydrostatic pressure on Yb(Rh1-xFex)2Si2 with x > 0.08 may cause a reappearance of antiferromagnetic order and it is highly interesting whether or not the T*(K) scale also reappears. Here, we present resistivity of Yb(Rh1-xFex)2Si2 with x = 0.105 under hydrostatic pressure and discuss our results in terms of the proposed interpretations.
Directory of Open Access Journals (Sweden)
S.-J. Choi
2014-06-01
Full Text Available In this paper, we present a dynamical core for the atmospheric primitive hydrostatic equations using a unified formulation of spectral element (SE and discontinuous Galerkin (DG methods in the horizontal direction with a finite difference (FD method in the radial direction. The CG and DG horizontal discretization employs high-order nodal basis functions associated with Lagrange polynomials based on Gauss–Lobatto–Legendre (GLL quadrature points, which define the common machinery. The atmospheric primitive hydrostatic equations are solved on the cubed-sphere grid using the flux form governing equations in a three-dimensional (3-D Cartesian space. By using Cartesian space, we can avoid the pole singularity problem due to spherical coordinates and this also allows us to use any quadrilateral-based grid naturally. In order to consider an easy way for coupling the dynamics with existing physics packages, we use a FD in the radial direction. The models are verified by conducting conventional benchmark test cases: the Rossby–Haurwitz wavenumber 4, Jablonowski–Williamson tests for balanced initial state and baroclinic instability, and Held–Suarez tests. The results from those tests demonstrate that the present dynamical core can produce numerical solutions of good quality comparable to other models.
International Nuclear Information System (INIS)
Stars in galaxies form in giant molecular clouds that coalesce when the atomic hydrogen is converted into molecules. There are currently two dominant models based on the property of the galactic disk that determines its molecular fraction: either hydrostatic pressure driven by the gravity of gas and stars, or a combination of gas column density and metallicity. To assess the validity of these models, we compare theoretical predictions to the observed atomic gas content of low-metallicity dwarf galaxies with high stellar densities. The extreme conditions found in these systems are optimal for distinguishing the two models, otherwise degenerate in nearby spirals. Locally, on scales <100 pc, we find that the state of the interstellar medium is mostly sensitive to the gas column density and metallicity rather than hydrostatic pressure. On larger scales where the average stellar density is considerably lower, both pressure and shielding models reproduce the observations, even at low metallicity. We conclude that models based on gas and dust shielding more closely describe the process of molecular formation, especially at the high resolution that can be achieved in modern galaxy simulations or with future radio/millimeter arrays.
Effects of hydrostatic pressure on yeasts isolated from deep-sea hydrothermal vents.
Burgaud, Gaëtan; Hué, Nguyen Thi Minh; Arzur, Danielle; Coton, Monika; Perrier-Cornet, Jean-Marie; Jebbar, Mohamed; Barbier, Georges
2015-11-01
Hydrostatic pressure plays a significant role in the distribution of life in the biosphere. Knowledge of deep-sea piezotolerant and (hyper)piezophilic bacteria and archaea diversity has been well documented, along with their specific adaptations to cope with high hydrostatic pressure (HHP). Recent investigations of deep-sea microbial community compositions have shown unexpected micro-eukaryotic communities, mainly dominated by fungi. Molecular methods such as next-generation sequencing have been used for SSU rRNA gene sequencing to reveal fungal taxa. Currently, a difficult but fascinating challenge for marine mycologists is to create deep-sea marine fungus culture collections and assess their ability to cope with pressure. Indeed, although there is no universal genetic marker for piezoresistance, physiological analyses provide concrete relevant data for estimating their adaptations and understanding the role of fungal communities in the abyss. The present study investigated morphological and physiological responses of fungi to HHP using a collection of deep-sea yeasts as a model. The aim was to determine whether deep-sea yeasts were able to tolerate different HHP and if they were metabolically active. Here we report an unexpected taxonomic-based dichotomic response to pressure with piezosensitve ascomycetes and piezotolerant basidiomycetes, and distinct morphological switches triggered by pressure for certain strains. PMID:26226336
Hydrostatic pressure cells development for X-ray and neutron experiments
International Nuclear Information System (INIS)
It was developed and built two pressure cell original models in order to be applied in X-ray elastic scattering (X-ray diffraction), X-ray absorption and neutron scattering experiments (neutron diffraction) under hydrostatic pressure. For the first two experimental cases, where X-ray beam is used, the pressure cell built with two B4C anvil mounted in a CuBe body. The B4C anvil was prepared at CTA research center in order to present an enhanced X-ray transparence and hardness. The special detail and advantage of the CuBe cell with B4C anvil is that this cell can be also used to measure de AC magnetic susceptibility in situ. This special characteristic is highlight as new concept of labeled here as multipurpose pressure cell. A second type of cell pressure was developed in order to be used in neutron elastic scattering experiments, specific in neutron diffraction experiments. The neutron cell pressure was developed using carbon fibers composite to improve the mechanical resistance a cylindrical geometry. The B4C pressure cells were available to researches in LNLS. The neutron pressure cell was given to research staff of IPEN Nuclear Reactor. This work show details and draws of these two types of hydrostatic pressure cells. (author)
B-splines as a Tool to Solve Constraints in Non-Hydrostatic Forecast Model
Subias, Alvaro
2016-01-01
Finite elements has been proven to be an useful tool to discretize the vertical coordinate in the hydrostatic forecast models allowing to define model variables in full levels so that no staggering is needed. In the non-hydrostatic case a constraint in the vertical operators appears (called C1) that does not allow to reduce the set of semi-implicit linear equations to a single equation in one variable as in the analytic case. Recently vertical finite elements based in B-splines have been used with an iterative method to relax the C1 constraint. In this paper we want to develop properly some representations of vertical operators in terms of B-splines in order to keep the C1-constraint. An invertibility relation between integral and derivative operators between vertical velocity and vertical divergence is also presented. The final scope of this paper is to provide a theoretical framework of development of finite element vertical operators to be implemented in the nh-Harmonie model
True-slime-mould-inspired hydrostatically coupled oscillator system exhibiting versatile behaviours
International Nuclear Information System (INIS)
Behavioural diversity is an indispensable attribute of living systems, which makes them intrinsically adaptive and responsive to the demands of a dynamically changing environment. In contrast, conventional engineering approaches struggle to suppress behavioural diversity in artificial systems to reach optimal performance in given environments for desired tasks. The goals of this research include understanding the essential mechanism that endows living systems with behavioural diversity and implementing the mechanism in robots to exhibit adaptive behaviours. For this purpose, we have focused on an amoeba-like unicellular organism: the plasmodium of true slime mould. Despite the absence of a central nervous system, the plasmodium exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously among these patterns. By exploiting this behavioural diversity, it is able to exhibit adaptive behaviour according to the situation encountered. Inspired by this organism, we built a real physical robot using hydrostatically coupled oscillators that produce versatile oscillatory patterns and spontaneous transitions among the patterns. The experimental results show that exploiting physical hydrostatic interplay—the physical dynamics of the robot—allows simple phase oscillators to promote versatile behaviours. The results can contribute to an understanding of how a living system generates versatile and adaptive behaviours with physical interplays among body parts. (paper)
Energy Technology Data Exchange (ETDEWEB)
Ash, J E; Marciniak, T J
1977-01-01
The Liquid Metal Fast Breeder Reactor (LMFBR) core structure consists of a matrix of hexagonal subassembly ducts. Evaluation of the safety aspects of the core structure requires that reliable computational procedures be available to predict the deformation response of the subassembly configuration to postulated local energy releases. Finite-element computer codes have been developed to calculate deflections and strains of a hexcan subassembly wrapper subjected to internal and external dynamic pressure loadings over a wide range of material-property conditions. An experimental and analytical program has been undertaken to validate and extend the codes for describing the core structural mechanics under reactor operating conditions, including, in particular, descriptions of possible subassembly-to-subassembly damage propagation. This report describes results of the first phase of the experimental program in which single hexcan sections were internally and externally hydrostatically pressurized out-of-pile at room temperature. The experimental data are compared with calculations from a two-dimensional finite-element structural-dynamics code, STRAW. Some additional comparisons were also made with calculations from a three-dimensional code, SADCAT. The correlations obtained between the computations and the hydrostatic experimental results were sufficiently good to validate the STRAW code and proceed to the next phase of the program involving the dynamic structural response.
Sub-zero temperature inactivation of carboxypeptidase Y under high hydrostatic pressure.
Kinsho, Toshihiko; Ueno, Hiroshi; Hayashi, Rikimaru; Hashizume, Chieko; Kimura, Kunio
2002-09-01
High hydrostatic pressure induced cold inactivation of carboxypeptidase Y. Carboxypeptidase Y was fully active when exposed to subzero temperature at 0.1 MPa; however, the enzyme became inactive when high hydrostatic pressure and subzero temperature were both applied. When the enzyme was treated at pressures higher than 300 MPa and temperatures lower than -5 degrees C, it underwent an irreversible inactivation in which nearly 50% of the alpha-helical structure was lost as judged by circular dichroism spectral analysis. When the applied pressure was limited to below 200 MPa, the cold inactivation process appeared to be reversible. In the presence of reducing agent, this reversible phenomenon, observed at below 200 MPa, diminished to give an inactive enzyme; the agent reduces some of disulfide bridge(s) in an area of the structure that is newly exposed area because of the cold inactivation. Such an area is unavailable if carboxypeptidase Y is in its native conformation. Because all the disulfide bridges in carboxypeptidase Y locate near the active site cleft, it is suggested that the structural destruction, if any, occurs preferentially in this disulfide rich area. A possible mechanism of pressure-dependent cold inactivation of CPY is to destroy the alpha-helix rich region, which creates an hydrophobic environment. This destruction is probably a result of the reallocation of water molecules. Experiments carried out in the presence of denaturing agents (SDS, urea, GdnHCl), salts, glycerol, and sucrose led to a conclusion consistent with the idea of water reallocation. PMID:12230580
Moussa, Marwen; Perrier-Cornet, Jean-Marie; Gervais, Patrick
2007-10-01
The relationship between membrane permeability, changes in ultrastructure, and inactivation in Escherichia coli strain K-12TG1 cells subjected to high hydrostatic pressure treatment at room and subzero temperatures was studied. Propidium iodide staining performed before and after pressure treatment made it possible to distinguish between reversible and irreversible pressure-mediated cell membrane permeabilization. Changes in cell ultrastructure were studied using transmission electron microscopy (TEM), which showed noticeable condensation of nucleoids and aggregation of cytosolic proteins in cells fixed after decompression. A novel technique used to mix fixation reagents with the cell suspension in situ under high hydrostatic pressure (HHP) and subzero-temperature conditions made it possible to show the partial reversibility of pressure-induced nucleoid condensation. However, based on visual examination of TEM micrographs, protein aggregation did not seem to be reversible. Reversible cell membrane permeabilization was noticeable, particularly for HHP treatments at subzero temperature. A correlation between membrane permeabilization and cell inactivation was established, suggesting different mechanisms at room and subzero temperatures. We propose that the inactivation of E. coli cells under combined HHP and subzero temperature occurs mainly during their transiently permeabilized state, whereas HHP inactivation at room temperature is related to a balance of transient and permanent permeabilization. The correlation between TEM results and cell inactivation was not absolute. Further work is required to elucidate the effects of pressure-induced damage on nucleoids and proteins during cell inactivation. PMID:17766454
Moussa, Marwen; Perrier-Cornet, Jean-Marie; Gervais, Patrick
2007-01-01
The relationship between membrane permeability, changes in ultrastructure, and inactivation in Escherichia coli strain K-12TG1 cells subjected to high hydrostatic pressure treatment at room and subzero temperatures was studied. Propidium iodide staining performed before and after pressure treatment made it possible to distinguish between reversible and irreversible pressure-mediated cell membrane permeabilization. Changes in cell ultrastructure were studied using transmission electron microscopy (TEM), which showed noticeable condensation of nucleoids and aggregation of cytosolic proteins in cells fixed after decompression. A novel technique used to mix fixation reagents with the cell suspension in situ under high hydrostatic pressure (HHP) and subzero-temperature conditions made it possible to show the partial reversibility of pressure-induced nucleoid condensation. However, based on visual examination of TEM micrographs, protein aggregation did not seem to be reversible. Reversible cell membrane permeabilization was noticeable, particularly for HHP treatments at subzero temperature. A correlation between membrane permeabilization and cell inactivation was established, suggesting different mechanisms at room and subzero temperatures. We propose that the inactivation of E. coli cells under combined HHP and subzero temperature occurs mainly during their transiently permeabilized state, whereas HHP inactivation at room temperature is related to a balance of transient and permanent permeabilization. The correlation between TEM results and cell inactivation was not absolute. Further work is required to elucidate the effects of pressure-induced damage on nucleoids and proteins during cell inactivation. PMID:17766454
Energy Technology Data Exchange (ETDEWEB)
Maj, P., E-mail: Piotr.maj@inmat.pw.edu.pl [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Adamczyk-Cieślak, B.; Mizera, J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Pachla, W. [High Pressure Research Center, Polish Academy of Sciences, Sokołowska 29, 01-142 Warsaw (Poland); Kurzydłowski, K.J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland)
2014-07-01
The nanostructure and mechanical properties of ferritic-austenitic duplex stainless steel subjected to hydrostatic extrusion were examined. The refinement of the structure in the initial state and in the two deformation states (ε = 1.4 and ε = 3.8) was observed in an optical microscope (OM) and a transmission electron microscope (TEM). The results indicate that the structure evolved from microcrystalline with a grain size of about 4 μm to nanocrystalline with a grain size of about 150 nm in ferrite and 70 nm in austenite. The material was characterized mechanically by tensile tests performed in the two deformation states. The ultimate strength appeared to increase significantly compared to that in the initial deformation stages, which can be attributed to the grain refinement and plastic deformation. The heterogeneity observed in microregions results from the dual-phase structure of the steel. The results indicate that hydrostatic extrusion is a highly potential technology suitable for improving the properties of duplex steels. - Highlights: • Duplex stainless steel was hydro extruded to a total strain of 3.8 • After the last stage of deformation heterogeneous structure was obtained in the material • As a result of stresses non-diffusive transformation γ→α’ occurred in the material • Nanometric (sub)grains were obtained in the austenite regions.
International Nuclear Information System (INIS)
The nanostructure and mechanical properties of ferritic-austenitic duplex stainless steel subjected to hydrostatic extrusion were examined. The refinement of the structure in the initial state and in the two deformation states (ε = 1.4 and ε = 3.8) was observed in an optical microscope (OM) and a transmission electron microscope (TEM). The results indicate that the structure evolved from microcrystalline with a grain size of about 4 μm to nanocrystalline with a grain size of about 150 nm in ferrite and 70 nm in austenite. The material was characterized mechanically by tensile tests performed in the two deformation states. The ultimate strength appeared to increase significantly compared to that in the initial deformation stages, which can be attributed to the grain refinement and plastic deformation. The heterogeneity observed in microregions results from the dual-phase structure of the steel. The results indicate that hydrostatic extrusion is a highly potential technology suitable for improving the properties of duplex steels. - Highlights: • Duplex stainless steel was hydro extruded to a total strain of 3.8 • After the last stage of deformation heterogeneous structure was obtained in the material • As a result of stresses non-diffusive transformation γ→α’ occurred in the material • Nanometric (sub)grains were obtained in the austenite regions
Neutron reflectometry studies of aluminum–saline water interface under hydrostatic pressure
International Nuclear Information System (INIS)
Highlights: • We investigated corrosion of aluminum via neutron reflectometry. • The hypothesis of an effect on corrosion due to hydrostatic pressure is confirmed. • The speed of corrosion is lower in the early stage compared to results found in the literature. • Nature of the corrosion compounds is investigated. - Abstract: The structural stability of Al layers in contact with 3.5 wt.% NaCl water solution was investigated at a temperature of 25 °C and hydrostatic pressures from 1 to 600 atm using neutron reflectometry. A pressure–temperature (P–T) Neutron Reflectometry (NR) cell developed at Los Alamos National Laboratory (LANL) was used to understand the behavior of thin (∼900 Å) aluminum layers in contact with saline liquid. Experimental results suggest that in the preliminary stages of corrosion the influence of pressure accelerates the mechanism of interactions of the oxide film with Cl− and H2O with lower speed compared to results found in the literature
Exciton states in GaAs δ-doped systems under magnetic fields and hydrostatic pressure
International Nuclear Information System (INIS)
Excitons in GaAs n-type δ-doped quantum wells are studied taking into account the effects of externally applied magnetic fields as well as of hydrostatic pressure. The one-dimensional potential profile in both the conduction and valence bands is described including Hartree effects via a Thomas–Fermi-based local density approximation. The allowed uncorrelated energy levels are calculated within the effective mass and envelope function approximations by means of an expansion over an orthogonal set of infinite well eigenfunctions and a variational method is used to obtain the exciton states. The results are presented as functions of the two-dimensional doping concentration and the magnetic field strength for zero and finite values of the hydrostatic pressure. In general, it is found that the exciton binding energy is a decreasing function of the doping-density and an increasing function of the magnetic field intensity. A comparison with recent experiments on exciton-related photoluminescence in n-type δ-doped GaAs is made
EDITORIAL: CAMOP: Quantum Non-Stationary Systems CAMOP: Quantum Non-Stationary Systems
Dodonov, Victor V.; Man'ko, Margarita A.
2010-09-01
Although time-dependent quantum systems have been studied since the very beginning of quantum mechanics, they continue to attract the attention of many researchers, and almost every decade new important discoveries or new fields of application are made. Among the impressive results or by-products of these studies, one should note the discovery of the path integral method in the 1940s, coherent and squeezed states in the 1960-70s, quantum tunneling in Josephson contacts and SQUIDs in the 1960s, the theory of time-dependent quantum invariants in the 1960-70s, different forms of quantum master equations in the 1960-70s, the Zeno effect in the 1970s, the concept of geometric phase in the 1980s, decoherence of macroscopic superpositions in the 1980s, quantum non-demolition measurements in the 1980s, dynamics of particles in quantum traps and cavity QED in the 1980-90s, and time-dependent processes in mesoscopic quantum devices in the 1990s. All these topics continue to be the subject of many publications. Now we are witnessing a new wave of interest in quantum non-stationary systems in different areas, from cosmology (the very first moments of the Universe) and quantum field theory (particle pair creation in ultra-strong fields) to elementary particle physics (neutrino oscillations). A rapid increase in the number of theoretical and experimental works on time-dependent phenomena is also observed in quantum optics, quantum information theory and condensed matter physics. Time-dependent tunneling and time-dependent transport in nano-structures are examples of such phenomena. Another emerging direction of study, stimulated by impressive progress in experimental techniques, is related to attempts to observe the quantum behavior of macroscopic objects, such as mirrors interacting with quantum fields in nano-resonators. Quantum effects manifest themselves in the dynamics of nano-electromechanical systems; they are dominant in the quite new and very promising field of circuit
International Nuclear Information System (INIS)
In this paper the surface topography of titanium samples irradiated by femtosecond laser pulses is described. When the fluence is about 0.5 J/cm2 periodic ripples with a period of about 700 nm are formed. For fluences between 0.5 and 2 J/cm2, a microcolumnar surface texture develops in the center of the irradiated spots and ripples are formed in the periphery of the spots. When experiments are performed with a non-stationary sample, the microcolumns exhibit ripples similar to those observed when the radiation fluence is about 0.5 J/cm2 and in the outer regions of the irradiated areas for fluences between 0.5 and 2 J/cm2. Since the energy distribution in the transverse cross-section of the laser beam is Gaussian, we conclude that the ripples form when the microcolumns are subjected to fluences near the melting threshold of the material at the trailing edge of the moving laser beam.
Modeling and Estimation of Stationary and Non-stationary Noises of Rubidium Atomic Clock
Directory of Open Access Journals (Sweden)
Deepak Mishra,
2014-07-01
Full Text Available Noise estimation of atomic clock is one of the important research areas in the field of atomic clock development and application. Most of the atomic clocks are having random-stochastic noises and periodic noises due to temperature variation. Random-stochastic noises have a well identified signature in time domain but periodic noises are difficult to analyze in time domain. However, in this paper, an effort is made to identify and analyze the deterministic trends of both random-stochastic noises and periodic noises due to variation in temperature using an alternate approach of least-squares normalized-error (LSNE regression algorithm. A MATLAB based application with graphical user interface (GUI is developed to estimate and analyze random-stochastic noises and periodic noises and re-estimate the stability of rubidium atomic clock after removing these noises from the raw phase data. The estimation of stationary noises are done using Allan variance from time domain data and noise profile is calculated using curve fit method. The estimation of periodic noises due to temperature variation is carried in frequency domain through spurious analysis of the frequency data of atomic clock.
A new stationary gridline artifact suppression method based on the 2D discrete wavelet transform
Energy Technology Data Exchange (ETDEWEB)
Tang, Hui, E-mail: corinna@seu.edu.cn [Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing 210096 (China); Key Laboratory of Computer Network and Information Integration (Southeast University), Ministry of Education, Nanjing 210000 (China); Centre de Recherche en Information Biomédicale sino-français, Laboratoire International Associé, Inserm, Université de Rennes 1, Rennes 35000 (France); Southeast University, Nanjing 210000 (China); Tong, Dan; Dong Bao, Xu [Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing 210096 (China); Dillenseger, Jean-Louis [INSERM, U1099, Rennes F-35000 (France); Université de Rennes 1, LTSI, Rennes F-35000 (France); Centre de Recherche en Information Biomédicale sino-français, Laboratoire International Associé, Inserm, Université de Rennes 1, Rennes 35000 (France); Southeast University, Nanjing 210000 (China)
2015-04-15
Purpose: In digital x-ray radiography, an antiscatter grid is inserted between the patient and the image receptor to reduce scattered radiation. If the antiscatter grid is used in a stationary way, gridline artifacts will appear in the final image. In most of the gridline removal image processing methods, the useful information with spatial frequencies close to that of the gridline is usually lost or degraded. In this study, a new stationary gridline suppression method is designed to preserve more of the useful information. Methods: The method is as follows. The input image is first recursively decomposed into several smaller subimages using a multiscale 2D discrete wavelet transform. The decomposition process stops when the gridline signal is found to be greater than a threshold in one or several of these subimages using a gridline detection module. An automatic Gaussian band-stop filter is then applied to the detected subimages to remove the gridline signal. Finally, the restored image is achieved using the corresponding 2D inverse discrete wavelet transform. Results: The processed images show that the proposed method can remove the gridline signal efficiently while maintaining the image details. The spectra of a 1D Fourier transform of the processed images demonstrate that, compared with some existing gridline removal methods, the proposed method has better information preservation after the removal of the gridline artifacts. Additionally, the performance speed is relatively high. Conclusions: The experimental results demonstrate the efficiency of the proposed method. Compared with some existing gridline removal methods, the proposed method can preserve more information within an acceptable execution time.
A new stationary gridline artifact suppression method based on the 2D discrete wavelet transform
International Nuclear Information System (INIS)
Purpose: In digital x-ray radiography, an antiscatter grid is inserted between the patient and the image receptor to reduce scattered radiation. If the antiscatter grid is used in a stationary way, gridline artifacts will appear in the final image. In most of the gridline removal image processing methods, the useful information with spatial frequencies close to that of the gridline is usually lost or degraded. In this study, a new stationary gridline suppression method is designed to preserve more of the useful information. Methods: The method is as follows. The input image is first recursively decomposed into several smaller subimages using a multiscale 2D discrete wavelet transform. The decomposition process stops when the gridline signal is found to be greater than a threshold in one or several of these subimages using a gridline detection module. An automatic Gaussian band-stop filter is then applied to the detected subimages to remove the gridline signal. Finally, the restored image is achieved using the corresponding 2D inverse discrete wavelet transform. Results: The processed images show that the proposed method can remove the gridline signal efficiently while maintaining the image details. The spectra of a 1D Fourier transform of the processed images demonstrate that, compared with some existing gridline removal methods, the proposed method has better information preservation after the removal of the gridline artifacts. Additionally, the performance speed is relatively high. Conclusions: The experimental results demonstrate the efficiency of the proposed method. Compared with some existing gridline removal methods, the proposed method can preserve more information within an acceptable execution time
Automatic Radiation Monitoring in Slovenia
International Nuclear Information System (INIS)
Full text: The automatic radiation monitoring system in Slovenia started in early nineties and now it comprises measurements of: 1. External gamma radiation: For the time being there are forty-three probes with GM tubes integrated into a common automatic network, operated at the SNSA. The probes measure dose rate in 30 minute intervals. 2. Aerosol radioactivity: Three automatic aerosol stations measure the concentration of artificial alpha and beta activity in the air, gamma emitting radionuclides, radioactive iodine 131 in the air (in all chemical forms, - natural radon and thoron progeny, 3. Radon progeny concentration: Radon progeny concentration is measured hourly and results are displayed as the equilibrium equivalent concentrations (EEC), 4. Radioactive deposition measurements: As a support to gamma dose rate measurements - the SNSA developed and installed an automatic measuring station for surface contamination equipped with gamma spectrometry system (with 3x3' NaI(Tl) detector). All data are transferred through the different communication pathways to the SNSA. They are collected in 30 minute intervals. Within these intervals the central computer analyses and processes the collected data, and creates different reports. Every month QA/QC analysis of data is performed, showing the statistics of acquisition errors and availability of measuring results. All results are promptly available at the our WEB pages. The data are checked and daily sent to the EURDEP system at Ispra (Italy) and also to the Austrian, Croatian and Hungarian authorities. (author)
Eating as an Automatic Behavior
Directory of Open Access Journals (Sweden)
Deborah A. Cohen, MD, MPH
2008-01-01
Full Text Available The continued growth of the obesity epidemic at a time when obesity is highly stigmatizing should make us question the assumption that, given the right information and motivation, people can successfully reduce their food intake over the long term. An alternative view is that eating is an automatic behavior over which the environment has more control than do individuals. Automatic behaviors are those that occur without awareness, are initiated without intention, tend to continue without control, and operate efficiently or with little effort. The concept that eating is an automatic behavior is supported by studies that demonstrate the impact of the environmental context and food presentation on eating. The amount of food eaten is strongly influenced by factors such as portion size, food visibility and salience, and the ease of obtaining food. Moreover, people are often unaware of the amount of food they have eaten or of the environmental influences on their eating. A revised view of eating as an automatic behavior, as opposed to one that humans can self-regulate, has profound implications for our response to the obesity epidemic, suggesting that the focus should be less on nutrition education and more on shaping the food environment.
Automatic Association of News Items.
Carrick, Christina; Watters, Carolyn
1997-01-01
Discussion of electronic news delivery systems and the automatic generation of electronic editions focuses on the association of related items of different media type, specifically photos and stories. The goal is to be able to determine to what degree any two news items refer to the same news event. (Author/LRW)
Automatic quantification of iris color
DEFF Research Database (Denmark)
Christoffersen, S.; Harder, Stine; Andersen, J. D.;
2012-01-01
An automatic algorithm to quantify the eye colour and structural information from standard hi-resolution photos of the human iris has been developed. Initially, the major structures in the eye region are identified including the pupil, iris, sclera, and eyelashes. Based on this segmentation, the ...
05501 Summary -- Automatic Performance Analysis
Gerndt, Hans Michael; Malony, Allen; Miller, Barton P.; Nagel, Wolfgang
2006-01-01
The Workshop on Automatic Performance Analysis (WAPA 2005, Dagstuhl Seminar 05501), held December 13-16, 2005, brought together performance researchers, developers, and practitioners with the goal of better understanding the methods, techniques, and tools that are needed for the automation of performance analysis for high performance computing.
Automatic Identification of Metaphoric Utterances
Dunn, Jonathan Edwin
2013-01-01
This dissertation analyzes the problem of metaphor identification in linguistic and computational semantics, considering both manual and automatic approaches. It describes a manual approach to metaphor identification, the Metaphoricity Measurement Procedure (MMP), and compares this approach with other manual approaches. The dissertation then…
The non-stationary random seismic response of structures
International Nuclear Information System (INIS)
A solution for the seismic excitation of structures is developed in terms of a non-stationary random response to a non-stationary input. The earthquake and the response are both described in terms of time varying probability density functions. The analysis is developed in detail for Gaussian PDF's, which are described solely by mean square values at any time. The theory is applied to a simple oscillator. The finite element representation of a structure resting on an infinite soil half space modelled by non-reflecting boundaries is also described and results validating the model to pulse time history inputs are presented
COMPRESSIBLE VORTEX RINGS AND THEIR INTERACTION WITH STATIONARY SURFACES
Mariani, Raffaello
2012-01-01
Experimental studies have been conducted on the topic of the interaction of compressiblevortex rings on stationary surfaces. Throughout the campaign experimentswere carried out at pressure ratios of ! 4, 8, and 12. In the classical set up of airas both the driver and driven gas, these corresponded to theoretical incident Machnumbers Ms of 1.34, 1.54, and 1.61.Experiments were conducted on vortex rings impinging on a stationary surfacelocated at three (increasing) distances (1.66, 3.33, and 5....
Local polynomial Whittle estimation covering non-stationary fractional processes
DEFF Research Database (Denmark)
Nielsen, Frank
This paper extends the local polynomial Whittle estimator of Andrews & Sun (2004) to fractionally integrated processes covering stationary and non-stationary regions. We utilize the notion of the extended discrete Fourier transform and periodogram to extend the local polynomial Whittle estimator to...... in.ated by a multiplicative constant. We show consistency and asymptotic normality for d ε (-1/2), and if the spectral density of the short-run component is in.nitely smooth near frequency zero we obtain an optimal rate of convergence for this setting, i.e. convergence arbitrarily close to the...
International Nuclear Information System (INIS)
The stability of the floor of a nuclear Plant (NPP) is continuously checked with existing levelling systems. In January 1999, the NPP of Flamanville (North-West of France) which is not equipped with such a system, decided to carry out an experimental measurement with a 'Hydrostatic Leveling System' (HLS), during the pressure test (for inspection air-tightness) of the surrounding wall. This paper will describe the conception, the installation of such a system and the results of the measurement. It is shown that the hydrostatic levelling system allows measurement of deformations in real-time with a very high accuracy. (author)
International Nuclear Information System (INIS)
Hydrostatic test waters can contain constituents such as oil and grease, iron, petroleum hydrocarbons, trace elements and polynuclear aromatic hydrocarbons. Various state agencies have a full range of permitting requirements for the discharge of the test water, as well as different requirements for compliance sampling and analysis. To the extent the behavior of constituents in the test water and the relationships between fill, pretest, and discharged waters can be determined, key monitoring parameters and sampling frequency may be identified to minimize the time and costs associated with the required characterization of the hydrostatic test water. The report is Volume 3 of a five-volume report series
DEFF Research Database (Denmark)
Henriksen, J H; Parving, H H; Christiansen, Lasse;
1981-01-01
and pigs with posthepatic portal hypertension and intraperitoneally instilled fluid were studied before and after abdominal paracentesis in order to evaluate the effect of ascitic fluid hydrostatic pressure on the transvascular escape rate of albumin. TERalb of the ascitic patients (n = 6) were on......, TERalb rose significantly to an average of 24.3% IVMalb.h-1. The increased albumin extravasation rate after removal of ascites is best explained by an increased sinusoidal-tissue pressure difference caused by a decreased hydrostatic fluid pressure in the liver interstitium (portal and subcapsular spaces...
Energy Technology Data Exchange (ETDEWEB)
Chua, J.O.
1975-06-01
The hypothesis that at low homologous temperature, the pressure effect on the yielding of metals is closely related to the effect of pressure on the elastic constants was tested. An apparatus in which tension tests can be made at liquid nitrogen temperature and high hydrostatic pressure was designed and constructed. Tension tests for potassium and lead were carried out at liquid nitrogen temperature and as a function of pressure up to 5.15 kbars. The results show that the effect of hydrostatic pressure was to raise the stress strain curves of both potassium and lead at liquid nitrogen temperature.
Directory of Open Access Journals (Sweden)
YAO Jili
2015-04-01
Full Text Available Terrestrial laser scanning (TLS technology has high speed of data acquisition, large amount of point cloud, long distance of measuring. However, there are some disadvantages such as distance limitation in target detecting, hysteresis in point clouds processing, low automation and weaknesses of adapting long-distance topographic survey. In this case, we put forward a method on long-range targets detecting in big point clouds orientation. The method firstly searches point cloud rings that contain targets according to their engineering coordinate system. Then the detected rings are divided into sectors to detect targets in a very short time so as to obtain central coordinates of these targets. Finally, the position and orientation parameters of scanner are calculated and point clouds in scanner's own coordinate system(SOCS are converted into engineering coordinate system. The method is able to be applied in ordinary computers for long distance topographic(the distance between scanner and targets ranges from 180 to 700 m survey in mountainous areas with targets radius of 0.162m.
Empirical Spectral Processes and Their Applications to Stationary Point Processes
Eichler, Michael
1995-01-01
We consider empirical spectral processes indexed by classes of functions for the case of stationary point processes. Conditions for the measurability and equicontinuity of these processes and a weak convergence result are established. The results can be applied to the spectral analysis of point processes. In particular, we discuss the application to parametric and nonparametric spectral density estimation.
Robust Forecasting of Non-Stationary Time Series
Croux, C.; Fried, R.; Gijbels, I.; Mahieu, K.
2010-01-01
This paper proposes a robust forecasting method for non-stationary time series. The time series is modelled using non-parametric heteroscedastic regression, and fitted by a localized MM-estimator, combining high robustness and large efficiency. The proposed method is shown to produce reliable foreca
Ceramic stationary gas turbine development. Final report, Phase 1
Energy Technology Data Exchange (ETDEWEB)
NONE
1994-09-01
This report summarizes work performed by Solar Turbines Inc. and its subcontractors during the period September 25, 1992 through April 30, 1993. The objective of the work is to improve the performance of stationary gas turbines in cogeneration through implementation of selected ceramic components.
Unsupervised Segmentation of Hidden Semi-Markov Non Stationary Chains
Lapuyade-Lahorgue, Jérôme; Pieczynski, Wojciech
2006-11-01
In the classical hidden Markov chain (HMC) model we have a hidden chain X, which is a Markov one and an observed chain Y. HMC are widely used; however, in some situations they have to be replaced by the more general "hidden semi-Markov chains" (HSMC) which are particular "triplet Markov chains" (TMC) T = (X, U, Y), where the auxiliary chain U models the semi-Markovianity of X. Otherwise, non stationary classical HMC can also be modeled by a triplet Markov stationary chain with, as a consequence, the possibility of parameters' estimation. The aim of this paper is to use simultaneously both properties. We consider a non stationary HSMC and model it as a TMC T = (X, U1, U2, Y), where U1 models the semi-Markovianity and U2 models the non stationarity. The TMC T being itself stationary, all parameters can be estimated by the general "Iterative Conditional Estimation" (ICE) method, which leads to unsupervised segmentation. We present some experiments showing the interest of the new model and related processing in image segmentation area.
Variance-optimal hedging for processes with stationary independent increments
DEFF Research Database (Denmark)
Hubalek, Friedrich; Kallsen, J.; Krawczyk, L.
We determine the variance-optimal hedge when the logarithm of the underlying price follows a process with stationary independent increments in discrete or continuous time. Although the general solution to this problem is known as backward recursion or backward stochastic differential equation, we...
Stationary space-periodic structures with equal diffusion coefficients
DEFF Research Database (Denmark)
Andresen, Peter Ragnar; Bache, Morten; Mosekilde, Erik;
1999-01-01
The paper investigates a chemical reaction-diffusion model in an open flow system. It is shown that such a system may, with particular boundary conditions, exhibit stationary space-periodic structures even in the case of equal diffusion coefficients. This is confirmed through numerical simulations....
Stability Analysis of Nonlinear Systems using Frozen Stationary Linearization
Hansson, Anders; Helmersson, Anders; Glad, Torkel
2003-01-01
This work discusses how to compute stability regions for nonlinear systems with slowly varying parameters using frozen stationary linearization. It is shown that larger stability regions can be obtained as compared to traditional approaches using recent stability results for linear parameter-varying systems.
Data-stationary Architecture to Execute Quantum Algorithms Classically
Burger, J. R.
2004-01-01
This paper presents a data stationary architecture in which each word has an attached address field. Address fields massively update in parallel to record data interchanges. Words do not move until memory is read for post processing. A sea of such cells can test large-scale quantum algorithms, although other programming is possible.
Stationary point process, Palm measure and collision risk
D'Estampes, Ludovic; Lezaud, Pascal
2013-01-01
The classical probability of collision between an aircraft whose the path crosses a flow of aircraft is derived under the assumption that it is described by a Poisson process. Using the so-called Palm measure, we extend the classical result to a stationary point process.
Estimation of limiting availability for a stationary bivariate process
Abraham, B.; Balakrishna, N
2000-01-01
We estimate the limiting availability of a system when the operating and repair times form a stationary bivariate sequence. These estimators are shown to be consistent and asymptotically normal under certain conditions. In particular, we estimate the limiting availability for a bivariate exponential autoregressive process.
Chiral Stationary Phases Based on Silica Modified by Helicenes
Czech Academy of Sciences Publication Activity Database
Bernard, Martin; Církva, Vladimír; Sýkora, Jan; Storch, Jan
- : -, 2014, s. 74. ISBN N. [Belgian Organic Synthesis Symposium (BOSS XIV) /14./. Louvain-la-Neuve (BE), 13.07.2014-18.07.2014] R&D Projects: GA TA ČR TA01010646 Institutional support: RVO:67985858 Keywords : chiral stationary phase * helicene * chiral resolution Subject RIV: CC - Organic Chemistry
Global equilibrium and local thermodynamics in stationary spacetimes
Panerai, Rodolfo
2016-05-01
In stationary spacetimes global equilibrium states can be defined, applying the maximum entropy principle, by the introduction of local thermodynamic fields determined solely by geometry. As an example, we study a class of equilibrium states for a scalar field in Einstein's static universe, characterized by inhomogeneous thermodynamic properties and nonvanishing angular momentum.
Hawking radiation via tunnelling from general stationary axisymmetric black holes
Institute of Scientific and Technical Information of China (English)
Zhang Jing-Yi; Fan Jun-Hui
2007-01-01
Hawking radiation is viewed as a tunnelling process. In this way the emission rates of massless particles and massive particles tunnelling across the event horizon of general stationary axisymmetric black holes are calculated,separately. The emission spectra of these two different kinds of outgoing particles have the same functional form and both are consistent with an underlying unitary theory.
Navigation safety caravan route towing in stationary traffic
Brazhny A. I.
2015-01-01
The questions of navigation safety of restricted sea-going object movement have been considered; the trajectory of a restricted sea-going object as part of tow caravan has been scientifically substantiated; the vector linear equation in stationary traffic has been solved
Stationary flow solution for water levels in open channels
Opheusden, van J.H.J.; Molenaar, J.; Beltman, W.H.J.; Adriaanse, P.I.
2010-01-01
We study stationary flow in open discharge channels. A model is derived from basic principles, which is solved numerically for the water level and discharge as a function of position along the channel. The model describes the effect of external inflow from fields adjacent to the channel. Several sce
Spin fluids in stationary axis-symmetric space-times
International Nuclear Information System (INIS)
The relations establishing the equivalence of an ordinary perfect fluid stress-energy tensor and a spin fluid stress-energy tensor are derived for stationary axis-symmetric space-times in general relativity. Spin fluid sources for the Goedel cosmology and the van Stockum metric are given
Spin fluids in stationary axis-symmetric space-times
Krisch, J. P.
1987-07-01
The relations establishing the equivalence of an ordinary perfect fluid stress-energy tensor and a spin fluid stress-energy tensor are derived for stationary axis-symmetric space-times in general relativity. Spin fluid sources for the Gödel cosmology and the van Stockum metric are given.
RAMAN MICROPROBE ANALYSIS OF STATIONARY SOURCE PARTICULATE POLLUTANTS
The application of Raman spectroscopy to the molecular characterization of individual particles from stationary sources is described. The NBS-developed Raman microprobe has been used to characterize microparticles of oil- and coal-fired power plant emissions and boiler samples co...
Stationary Engineering, Environmental Control, Refrigeration. Science I--Teachers Guide.
Steingress, Frederick M.; And Others
The document presents lessons for teaching about occupations related to environmental control, stationary engineering, and refrigeration. Intended for use with the assignments in the related science manual for students, each unit provides the teacher with objectives, a list of aids needed, procedures, a summary, and testing questions. There are 18…
Stationary Engineering, Environmental Control, Refrigeration. Science Manual I.
Steingress, Frederick M.; And Others
The student materials present lessons about occupations related to environmental control, stationary engineering, and refrigeration. Included are 18 units organized by objective, information, reference, procedure, and assignment. Each lesson involves concrete trade experience where science is applied. Unit titles are: safety and housekeeping,…
The spectral analysis of cyclo-non-stationary signals
Abboud, D.; Baudin, S.; Antoni, J.; Rémond, D.; Eltabach, M.; Sauvage, O.
2016-06-01
Condition monitoring of rotating machines in speed-varying conditions remains a challenging task and an active field of research. Specifically, the produced vibrations belong to a particular class of non-stationary signals called cyclo-non-stationary: although highly non-stationary, they contain hidden periodicities related to the shaft angle; the phenomenon of long term modulations is what makes them different from cyclostationary signals which are encountered under constant speed regimes. In this paper, it is shown that the optimal way of describing cyclo-non-stationary signals is jointly in the time and the angular domains. While the first domain describes the waveform characteristics related to the system dynamics, the second one reveals existing periodicities linked to the system kinematics. Therefore, a specific class of signals - coined angle-time cyclostationary is considered, expressing the angle-time interaction. Accordingly, the related spectral representations, the order-frequency spectral correlation and coherence functions are proposed and their efficiency is demonstrated on two industrial cases.
Stationary and axisymmetric solutions of higher-dimensional general relativity
International Nuclear Information System (INIS)
We study stationary and axisymmetric solutions of General Relativity, i.e., pure gravity, in four or higher dimensions. D-dimensional stationary and axisymmetric solutions are defined as having D-2 commuting Killing vector fields. We derive a canonical form of the metric for such solutions that effectively reduces the Einstein equations to a differential equation on an axisymmetric D-2 by D-2 matrix field living in three-dimensional flat space (apart from a subclass of solutions that instead reduce to a set of equations on a D-2 by D-2 matrix field living in two-dimensional flat space). This generalizes the Papapetrou form of the metric for stationary and axisymmetric solutions in four dimensions, and furthermore generalizes the work on Weyl solutions in four and higher dimensions. We analyze then the sources for the solutions, which are in the form of thin rods along a line in the three-dimensional flat space that the matrix field can be seen to live in. As examples of stationary and axisymmetric solutions, we study the five-dimensional rotating black hole and the rotating black ring, write the metrics in the canonical form and analyze the structure of the rods for each solution
Stationary spectra in a sheared plasma (linear limit)
International Nuclear Information System (INIS)
The short-wave low-frequency stationary spectra of correlated electromagnetic fluctuations in a sheared current-currying plasma, are obtained in a linear approximation. Even being weak, the shear may considerably alter the spectral characteristics of plasma perturbations. 3 refs. (author)
Linear stationary states of dissipative modes in cylindrical geometry
International Nuclear Information System (INIS)
The theory of resistive instabilities (tearing and interchange) has been reworked including the full collisional viscous tensor and thermal conductivity in cylindrical geometry. Particular attention is devoted to the existence of stationary states made possible by the presence of viscous effects. These states are important as they form the basis for calculating anomalous heat transport in weakly nonlinear regimes
On the generation techniques of axially symmetric stationary metrics
Indian Academy of Sciences (India)
S Chaudhuri
2002-03-01
In the present paper, a relationship between the method of Gutsunaev–Manko and the soliton technique (for two-soliton solutions) of Belinskii–Zakharov, for generating solutions of axially symmetric stationary space-times in general relativity is discussed.
Institute of Scientific and Technical Information of China (English)
ZHAO Jianhua; LIANG Yingna; GAO Dianrong
2014-01-01
Durning the design process of hydrostatic rotary worktable, the processing and assembly tolerance, (the offset of worktable and the gap of the oil film’s thickness) is ignored. But it will cause that the real bearing of oil pocket deviates from the initial design value, and then the performance of rotary worktable will be reduced significantly. Up to now, no effort is found toward the research of influence of the processing and assembly tolerance on the performance of the rotary worktable. So the hydrostatic oil film is assumed as the elastomer in this paper, and then the bearing capacity of the oil pocket is studied with and without the mass offset of the worktable by taking an expression between the bearing capacity and the oil film’s thickness of the oil pocket as the deform compatibility equation. The influence of the processing tolerance of the oil sealing belt’s gap on the bearing capacity of the oil pocket is analyzed. In the light of the liquid hydrostatic worktable of Gantry Moving Milling Center using on the scene, the oil pocket’s pressure of the worktable is tested using Rotary Worktable Test System under the circumstance of the mass offset of the worktable and the gap tolerance of the oil sealing belt, and then the equivalent offset of worktable, the average pressure of the oil pocket and the actual thickness of the oil film are analyzed respectively. The test results show that the bearing capacity component of the oil pocket caused by G is consistent, and the component caused by M is relative to the position of the oil pocket. When the oil sealing belt’s gap is larger than the theoretical value, the bearing capacity of the oil pocket is smaller than the others;whereas the bearing capacity of the oil pocket is larger than the others. The maximum and minimum equivalent offsets are 0.256 4 mm and 0.047 5 mm, respectively, and the average oil pocket pressure varies from 0.345 MPa to 0.460 MPa, the maximum and minimum value of the actual oil film
Orbital welding automatic pressure test by ODA automatic machines is 35 years old
International Nuclear Information System (INIS)
Development review of technology and equipment of automatic orbital welding with automatic pressures test of nuclear power stations pipelines and different purpose objects is performed. Welding variants with automatic pressure test and different welding automatic machines are described. Priority of national developments is underlined