Feedback stabilization of plasma instabilities
International Nuclear Information System (INIS)
Cap, F.F.
1977-01-01
This paper reviews the theoretical and experimental aspects of feedback stabilization. After giving an outline of a general theoretical model for electrostatic instabilities the author provides a theoretical analysis of the suppression of various types of instability. Experiments which have been carried out on the feedback stabilization of various types of plasma instability are reported. An extensive list of references is given. (B.R.H.)
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.
Fiscal and Financial Stability in Romania - An Overview
Directory of Open Access Journals (Sweden)
Florin OPREA
2013-10-01
Full Text Available The recent financial crisis has seriously shaken economies around the world, and raised serious doubts about the long-term viability of the public policies to remedy market imperfections. The effect has been pronounced for Romania, a newly transitioned country with a fragile market economy due to political, economic and social consequents. This paper examines the correlation between fiscal policy and financial stability in Romania in the period from 1990 to 2011. Specifically, we analyze the country’s main monetary and fiscal policy decisions and their associations with macro-economic variables, highlighting the requirements for a sustainable macro-economic policy and whether such requirements have been met in Romania. Based on the results, we further outline recommendations to improve Romania’s public policy initiatives, considering the specific correlations between monetary and fiscal policies. The results for the period under study indicate that fiscal and monetary policies promoted in Romania have not been consistently harmonized, at times lacking necessary mutual support, or even generating conflicting outcomes favorable to the manifestation of fiscal and financial instability.
THEORETICAL CONSIDERATIONS REGARDING THE AUTOMATIC FISCAL STABILIZERS OPERATING MECHANISM
Directory of Open Access Journals (Sweden)
Gondor Mihaela
2012-07-01
Full Text Available This paper examines the role of Automatic Fiscal Stabilizers (AFS for stabilizing the cyclical fluctuations of macroeconomic output as an alternative to discretionary fiscal policy, admitting its huge potential of being an anti crisis solution. The objectives of the study are the identification of the general features of the concept of automatic fiscal stabilizers and the logical assessment of them from economic perspectives. Based on the literature in the field, this paper points out the disadvantages of fiscal discretionary policy and argue the need of using Automatic Fiscal Stabilizers in order to provide a faster decision making process, shielded from political interference, and reduced uncertainty for households and business environment. The paper conclude about the need of using fiscal policy for smoothing the economic cycle, but in a way which includes among its features transparency, responsibility and clear operating mechanisms. Based on the research results the present paper assumes that pro-cyclicality reduces de effectiveness of the Automatic Fiscal Stabilizer and as a result concludes that it is very important to avoid the pro-cyclicality in fiscal rule design. Moreover, by committing in advance to specific fiscal policy action contingent on economic developments, uncertainty about the fiscal policy framework during a recession should be reduced. Being based on logical analysis and not focused on empirical, contextualized one, the paper presents some features of AFS operating mechanism and also identifies and systematizes the factors which provide its importance and national individuality. Reaching common understanding on the Automatic Fiscal Stabilizer concept as a institutional device for smoothing the gap of the economic cycles across different countries, particularly for the European Union Member States, will facilitate efforts to coordinate fiscal policy responses during a crisis, especially in the context of the fiscal
Does the Credible Fiscal Policy Support the Prices Stabilization?
Directory of Open Access Journals (Sweden)
Kuncoro Haryo
2015-06-01
Full Text Available This paper aims at analyzing the co-movement between fiscal policy and monetary policy rules in the context of price stabilization. More specifically, we observe the potential impact of fiscal policy credibility on the price stabilization in the inflation targeting framework. Motivated by the fact that empirical studies concerning this aspect are still limited, we take the case of Indonesia over the period 2001-2013. Based on the quarterly data analysis, we found that the impact of credibility typically depends on characteristics of fiscal rules commitment. On one hand, the credibility of debt rule reduces the inflation rate. In contrast, the incredible deficit rule policy does not have any impact on the inflation rate and therefore does not support to inflation targeting. Given those results, we conclude that credibility matters in stabilizing price levels. Accordingly, those findings suggest tightening coordination between monetary and fiscal policy to maintain fiscal sustainability in accordance with price stabilization policy
Feedback stabilization of electrostatic reactive instabilities
International Nuclear Information System (INIS)
Richards, R.K.
1976-01-01
A general theory for the feedback stabilization of electrostatic reactive instabilities is developed which includes the effects of dissipation in the plasma and frequency dependence in the sensor-suppressor elements and in the external feedback circuit. This theory is compared to experiments involving particular reactive instability, an interchange mode, found in a magnetic mirror device; these results are found to be in good agreement with theory. One noteworthy result is that a frequency dependence in the overall gain and phase shift of the feedback loop can cause destabilization at large gain. Multimode feedback stabilization is studied using the spatial variation of two interchange modes to separate them such that each can be acted upon individually by the feedback system. The transfer function of the plasma is also examined. This analysis is used for mode identification and location of the pole positions. As an example of using feedback as a diagnostic tool, instability induced transport is studied. Here feedback is used to control the amplitude of fluctuations at saturation
Semiconductor Lasers Stability, Instability and Chaos
Ohtsubo, Junji
2013-01-01
This third edition of “Semiconductor Lasers, Stability, Instability and Chaos” was significantly extended. In the previous edition, the dynamics and characteristics of chaos in semiconductor lasers after the introduction of the fundamental theory of laser chaos and chaotic dynamics induced by self-optical feedback and optical injection was discussed. Semiconductor lasers with new device structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are interesting devices from the viewpoint of chaotic dynamics since they essentially involve chaotic dynamics even in their free-running oscillations. These topics are also treated with respect to the new developments in the current edition. Also the control of such instabilities and chaos control are critical issues for applications. Another interesting and important issue of semiconductor laser chaos in this third edition is chaos synchronization between two lasers and the application to optical secure communication. One o...
Semiconductor Lasers Stability, Instability and Chaos
Ohtsubo, Junji
2008-01-01
This monograph describes fascinating recent progress in the field of chaos, stability and instability of semiconductor lasers. Applications and future prospects are discussed in detail. The book emphasizes the various dynamics induced in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Recent results of both theoretical and experimental investigations are presented. Demonstrating applications of semiconductor laser chaos, control and noise, Semiconductor Lasers describes suppression and chaotic secure communications. For those who are interested in optics but not familiar with nonlinear systems, a brief introduction to chaos analysis is presented.
Fiscal policy and its implications for monetary and financial stability
Bank for International Settlements
2011-01-01
The BIS 10th Annual Conference took place in Lucerne, Switzerland on 23-24 June 2011. The event brought together senior representatives of central banks and academic institutions, who exchanged views on the conference theme of "Fiscal policy and its implications for monetary and financial stability". This volume contains the opening address of Stephen Cecchetti (Economic Adviser, BIS), a keynote address from Martin Feldstein, and the contributions of the policy panel on "Fiscal policy sustain...
Semiconductor lasers stability, instability and chaos
Ohtsubo, Junji
2017-01-01
This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...
Liquidity Constraints and Fiscal Stabilization Policy
DEFF Research Database (Denmark)
Kristoffersen, Mark Strøm
It is often claimed that the presence of liquidity constrained households enhances the need for and the effects of fi…scal stabilization policies. This paper studies this in a model of a small open economy with liquidity constrained households. The results show that the consequences of liquidity...... constraints are more complex than previously thought: The optimal stabilization policy in case of productivity shocks is independent of the liquidity constraints, and the presence of liquidity constraints tends to reduce the need for an active policy stabilizing productivity shocks....
Fiscal Deficits, Monetary Reform and Inflation Stabilization in Romania.
van Wijnbergen, S.J.G.; Budina, N.
2001-01-01
Investigates the consistency between inflation, monetary reform and fiscal policy in Romania. Offers a framework for the assessment of the fiscal and monetary interactions of Romanian economy; Shows impact of inflation on fiscal inconsistency measure; Considers importance of consolidating public
The role of proprioception and neuromuscular stability in carpal instabilities.
Hagert, E; Lluch, A; Rein, S
2016-01-01
Carpal stability has traditionally been defined as dependent on the articular congruity of joint surfaces, the static stability maintained by intact ligaments, and the dynamic stability caused by muscle contractions resulting in a compression of joint surfaces. In the past decade, a fourth factor in carpal stability has been proposed, involving the neuromuscular and proprioceptive control of joints. The proprioception of the wrist originates from afferent signals elicited by sensory end organs (mechanoreceptors) in ligaments and joint capsules that elicit spinal reflexes for immediate joint stability, as well as higher order neuromuscular influx to the cerebellum and sensorimotor cortices for planning and executing joint control. The aim of this review is to provide an understanding of the role of proprioception and neuromuscular control in carpal instabilities by delineating the sensory innervation and the neuromuscular control of the carpus, as well as descriptions of clinical applications of proprioception in carpal instabilities. © The Author(s) 2015.
Shear flow stabilization of the hydromagnetic Rayleigh-Taylor instability
International Nuclear Information System (INIS)
Roderick, N.F.; Shumlak, U.; Douglas, M.; Peterkin, R.E. Jr.; Ruden, E.
1997-01-01
Numerical simulations have indicated that shear flow may help stabilize the hydromagnetic Rayleigh-Taylor instability in imploding plasma z-pinches. A simple extension to a model presented in Chandrasekhar has been developed to study the linear stability of incompressible plasma subjected to both a shear flow and acceleration. The model has been used to investigate the stability plasma implosion schemes using externally imposed velocity shear which develops from the plasma flow itself. Specific parameters were chosen to represent plasma implosions driven by the Saturn and PBFA-Z, pulsed power generators at Sandia National Laboratories. Results indicate a high shear is necessary to stabilize the z-pinch implosions studied
Stability and instability of stationary solutions for sublinear parabolic equations
Kajikiya, Ryuji
2018-01-01
In the present paper, we study the initial boundary value problem of the sublinear parabolic equation. We prove the existence of solutions and investigate the stability and instability of stationary solutions. We show that a unique positive and a unique negative stationary solutions are exponentially stable and give the exact exponent. We prove that small stationary solutions are unstable. For one space dimensional autonomous equations, we elucidate the structure of stationary solutions and study the stability of all stationary solutions.
Conducting grids to stabilize MHD generator plasmas against ionization instabilities
International Nuclear Information System (INIS)
Veefkind, A.
1972-09-01
Ionization instabilities in MHD generators may be suppressed by the use of grids that short circuit the AC electric field component corresponding to the direction of maximum growth. An analysis of the influence of the corresponding boundary conditions has been performed in order to obtain more quantitative information about the stabilizing effect of this system
Monetary Policy and Financial (InStability
Directory of Open Access Journals (Sweden)
Adam Koronowski
2010-06-01
Full Text Available This paper presents how monetary policy, restricted only by price stability, may easily become propitious to asset inflation and – eventually – to a financial crisis. This risk is particularly high when the financial system lacks proper regulation and effective supervision. Hasty liberalization, negligence of official oversight and „Greenspan doctrine” which refuted any activist policy promoting financial stability characterized Fed’s monetary policy under the former Fed’s governor. The paper also analyses another aspect of the linkages between monetary policy and financial crises – monetary policy reaction to financial crises. It is not surprising that it consists of cutting interest rates and bail-out of insolvent, systemically important financial institutions. Such policy, especially when run too long and changed too abruptly, not only creates moral hazards but it also sets the stage for another „search for yield” and build-up of another speculative bubble. As a result, monetary policy becomes asymmetric and pro-cyclical. Fed’s reaction to the recent crisis seems to be very much in line with this pattern typical of Fed’s policy in the past. However, this time the scale of flooding the economy with liquidity and – as a consequence – the risks of future major imbalances in the financial system are unprecedented. A general conclusion of the paper says that there can’t be a sound financial and economic system unless money itself is a scarce resource. However trivial this statement is, monetary policy of some central banks seems to miss the point.
Krueger, David; Kraus, Natascha; Pauly, Stephan; Chen, Jianhai; Scheibel, Markus
2011-01-01
The value of arthroscopic revision shoulder stabilization after failed instability repair is still a matter of debate. Arthroscopic revision shoulder stabilization using suture anchors provides equivalent subjective and objective results compared with initial arthroscopic instability repair. Cohort study; Level of evidence, 3. Twenty consecutive patients who underwent arthroscopic revision shoulder stabilization using suture anchors (group 2) were matched for age, gender, and handedness (dominant or nondominant) with 20 patients who had initial arthroscopic instability repair using the same technique (group 1). At the time of follow-up, a complete physical examination of both shoulders and evaluation with the Rowe score, Walch-Duplay score, Melbourne Instability Shoulder Score, Western Ontario Shoulder Instability Index, and the Subjective Shoulder Value were performed. In addition, standard radiographs (true AP and axillary views) were taken to evaluate signs of osteoarthritis. After a minimum follow-up of 24 months, no recurrent dislocations were observed in either group. The apprehension sign was positive in 2 cases of revision surgery (0 vs 2; P > .05). No significant differences in the Rowe score (89 vs 81.8 points) were found between groups 1 and 2 (P > .05). However, group 2 revealed significantly lower scores in the Walch-Duplay score (85.3 vs 75.5 points), Melbourne Instability Shoulder Score (90.2 vs 73.7 points), Western Ontario Shoulder Instability Index (89.8% vs 68.9%), and Subjective Shoulder Value (91.8% vs 69.2%) (P instability arthropathy were found more often in patients with arthroscopic revision surgery (2 vs 5; P > .05). Arthroscopic revision shoulder stabilization is associated with a lower subjective outcome compared with initial arthroscopic stabilization. The objective results found in this study may overestimate the clinical outcome in this patient population.
Recurrent instability after revision anterior shoulder stabilization surgery.
Friedman, Lisa Genevra Mandeville; Griesser, Michael J; Miniaci, Anthony A; Jones, Morgan H
2014-03-01
The purpose of this study was to perform a systematic review of the literature to compare outcomes of revision anterior stabilization surgeries based on technique. This study also sought to compare the impact of bone defects on outcomes. A systematic review of the electronic databases PubMed, Cochrane Central Register of Controlled Trials, and Scopus was performed in July 2012 and March 2013. Of 345 articles identified in the search, 17 studies with Level I to IV Evidence satisfied the inclusion criteria and were analyzed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Recurrent instability was defined as redislocation, resubluxation, or a positive apprehensive test after revision surgery. Procedures were categorized as arthroscopic Bankart repair, open Bankart repair, Bristow-Latarjet procedure, and other open procedures. In total, 388 shoulders were studied. Male patients comprised 74.1% of patients, 66.7% of cases involved the dominant shoulder, the mean age was 28.2 years, and the mean follow-up period was 44.2 months. The surgical procedures classified as "other open procedures" had the highest rate of recurrent instability (42.7%), followed by arthroscopic Bankart repair (14.7%), the Bristow-Latarjet procedure (14.3%), and open Bankart repair (5.5%). Inconsistent reporting of bone defects precluded drawing significant conclusions. A number of different procedures are used to address recurrent instability after a primary operation for anterior shoulder instability has failed. There is significant variability in the rate of recurrent instability after revision anterior shoulder stabilization surgery. Level IV, systematic review of Level I to IV studies. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
The Growth and Stabilization Properties of Fiscal Policy in Malaysia
Sohrab Rafiq
2013-01-01
This paper examines the size of the fiscal multiplier values generated in Malaysia. The results show that a government spending shock leads to broad positive economic effects. Although, the effectiveness of fiscal policy alters across macroeconomic states. The estimates show that since the Asian financial crisis the medium- and long-run effect of fiscal policy spending has declined. Some of this is down to greater credit availability and less investment spending.
Stabilization of magnetohydrodynamic instabilities in a current-carrying stellarator
International Nuclear Information System (INIS)
Matsuoka, K.; Miyamoto, K.
1979-02-01
Stable profiles against MHD instabilities are given in a cylindrical current-carrying stellarator. The comparison theorem, i.e., guiding principle for stabilization, is obtained in the same way as in a tokamak. As the external rotational transform due to an l = 2 helical field increases, MHD properties in a stellarator are improved than in a tokamak and the minimum value of q(a) which provides simultaneous stabilization of MHD modes can be lowered less than 2 even without a conducting shell. In an l = 3 stellarator, however, as shown from the Euler equation, the configuration becomes more unstable than in a tokamak and strong tailoring of the current profile is necessary in order to stabilize MHD modes. (author)
Stability and instability of hydromagnetic Taylor-Couette flows
Rüdiger, Günther; Gellert, Marcus; Hollerbach, Rainer; Schultz, Manfred; Stefani, Frank
2018-04-01
Decades ago S. Lundquist, S. Chandrasekhar, P. H. Roberts and R. J. Tayler first posed questions about the stability of Taylor-Couette flows of conducting material under the influence of large-scale magnetic fields. These and many new questions can now be answered numerically where the nonlinear simulations even provide the instability-induced values of several transport coefficients. The cylindrical containers are axially unbounded and penetrated by magnetic background fields with axial and/or azimuthal components. The influence of the magnetic Prandtl number Pm on the onset of the instabilities is shown to be substantial. The potential flow subject to axial fields becomes unstable against axisymmetric perturbations for a certain supercritical value of the averaged Reynolds number Rm bar =√{ Re ṡ Rm } (with Re the Reynolds number of rotation, Rm its magnetic Reynolds number). Rotation profiles as flat as the quasi-Keplerian rotation law scale similarly but only for Pm ≫ 1 while for Pm ≪ 1 the instability instead sets in for supercritical Rm at an optimal value of the magnetic field. Among the considered instabilities of azimuthal fields, those of the Chandrasekhar-type, where the background field and the background flow have identical radial profiles, are particularly interesting. They are unstable against nonaxisymmetric perturbations if at least one of the diffusivities is non-zero. For Pm ≪ 1 the onset of the instability scales with Re while it scales with Rm bar for Pm ≫ 1. Even superrotation can be destabilized by azimuthal and current-free magnetic fields; this recently discovered nonaxisymmetric instability is of a double-diffusive character, thus excluding Pm = 1. It scales with Re for Pm → 0 and with Rm for Pm → ∞. The presented results allow the construction of several new experiments with liquid metals as the conducting fluid. Some of them are described here and their results will be discussed together with relevant diversifications of
Drinking-Straw Microbalance and Seesaw: Stability and Instability
Chapman, Peter; Glasser, Leslie
2015-03-01
The mechanics of a beam balance are little appreciated and seldom understood. We here consider the conditions that result in a stable balance, with center of gravity below the fulcrum (pivot point), while an unstable balance results when the center of gravity is above the fulcrum. The highly sensitive drinking-straw microbalance, which uses a plastic drinking straw as a rigid beam, is briefly described with some slight convenient modifications. Different placements of the center of gravity are considered analytically to explain the equilibrium neutrality, stability, and instability of such beam balances as the microbalance, the playground "seesaw" or "teeter-totter," the "dipping bird," and other toys and magic tricks.
Fiscal aspects of European monetary integration
DEFF Research Database (Denmark)
Hallett, Andrew Hughes; Hutchison, Michael; Hougaard Jensen, Svend E.
of fiscal policy in EMU. The contributors are experienced analysts in the field. Topics covered include the need for and consequences of fiscal co-ordination, constraints on national deficits and debt levels (the Stability Pact), and the role of fiscal federalism and insurance. The importance of co......-ordinating fiscal and monetary policies is also considered in depth. As long as these strategic and institutional aspects remain imperfectly understood, EMU will not be able to function to its full advantage and may suffer periods of instability or weakness. Contains 11 papers and three review essays, which analyze...
Instability Suppression in a Swirl-Stabilized Combustor Using Microjet Air Injection
LaBry, Zachary
2010-01-04
In this study, we examine the effectiveness of microjet air injection as a means of suppressing thermoacoustic instabilities in a swirl-stabilized, lean-premixed propane/air combustor. High-speed stereo PIV measurements, taken to explore the mechanism of combustion instability, reveal that the inner recirculation zone plays a dominant role in the coupling of acoustics and heat release that leads to combustion instability. Six microjet injector configurations were designed to modify the inner and outer recirculation zones with the intent of decoupling the mechanism leading to instability. Microjets that injected air into the inner recirculation zone, swirling in the opposite sense to the primary swirl were effective in suppressing combustion instability, reducing the overall sound pressure level by up to 17 dB within a certain window of operating conditions. Stabilization was achieved near an equivalence ratio of 0.65, corresponding to the region where the combustor transitions from a 40 Hz instability mode to a 110 Hz instability mode. PIV measurements made of the stabilized flow revealed significant modification of the inner recirculation zone and substantial weakening of the outer recirculation zone.
Synchrophasor-Assisted Prediction of Stability/Instability of a Power System
Saha Roy, Biman Kumar; Sinha, Avinash Kumar; Pradhan, Ashok Kumar
2013-05-01
This paper presents a technique for real-time prediction of stability/instability of a power system based on synchrophasor measurements obtained from phasor measurement units (PMUs) at generator buses. For stability assessment the technique makes use of system severity indices developed using bus voltage magnitude obtained from PMUs and generator electrical power. Generator power is computed using system information and PMU information like voltage and current phasors obtained from PMU. System stability/instability is predicted when the indices exceeds a threshold value. A case study is carried out on New England 10-generator, 39-bus system to validate the performance of the technique.
Ji, H.; Burin, M.; Schartman, E.; Goodman, J.; Liu, W.
2006-01-01
Two plausible mechanisms have been proposed to explain rapid angular momentum transport during accretion processes in astrophysical disks: nonlinear hydrodynamic instabilities and magnetorotational instability (MRI). A laboratory experiment in a short Taylor-Couette flow geometry has been constructed in Princeton to study both mechanisms, with novel features for better controls of the boundary-driven secondary flows (Ekman circulation). Initial results on hydrodynamic stability have shown negligible angular momentum transport in Keplerian-like flows with Reynolds numbers approaching one million, casting strong doubt on the viability of nonlinear hydrodynamic instability as a source for accretion disk turbulence.
Energy Technology Data Exchange (ETDEWEB)
Adams, Colin Stuart [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Univ. of Washington, Seattle, WA (United States)
2015-01-15
The Rayleigh-Taylor instability causes mixing in plasmas throughout the universe, from micron-scale plasmas in inertial confinement fusion implosions to parsec-scale supernova remnants. The evolution of this interchange instability in a plasma is influenced by the presence of viscosity and magnetic fields, both of which have the potential to stabilize short-wavelength modes. Very few experimental observations of Rayleigh-Taylor growth in plasmas with stabilizing mechanisms are reported in the literature, and those that are reported are in sub-millimeter scale plasmas that are difficult to diagnose. Experimental observations in well-characterized plasmas are important for validation of computational models used to make design predictions for inertial confinement fusion efforts. This dissertation presents observations of instability growth during the interaction between a high Mach-number, initially un-magnetized plasma jet and a stagnated, magnetized plasma. A multi-frame fast camera captures Rayleigh-Taylor-instability growth while interferometry, spectroscopy, photodiode, and magnetic probe diagnostics are employed to estimate plasma parameters in the vicinity of the collision. As the instability grows, an evolution to longer mode wavelength is observed. Comparisons of experimental data with idealized magnetohydrodynamic simulations including a physical viscosity model suggest that the observed instability evolution is consistent with both magnetic and viscous stabilization. These data provide the opportunity to benchmark computational models used in astrophysics and fusion research.
International Nuclear Information System (INIS)
2001-07-01
This report gives a general presentation of energy fiscality in France: taxes on energy, mechanisms of stabilization of government's fiscal incomes in case of significant oil prices change, some particularities of energy taxes, the fiscality according to the energy content and according to the carbon content. The fiscality of petroleum products (automotive fuels and other products), natural gas and electricity in France is presented in appendixes together with a comparison of the fiscality in use in the rest of Europe (automotive fuels, domestic fuels, natural gas and electricity for domestic use and for industrial use). (J.S.)
International Nuclear Information System (INIS)
Bud'ko, A.B.; Liberman, M.A.
1992-01-01
In the framework of WKB approximation the problem is studied of stabilizing the Rayleigh - Taylor instability with unhomogeneous convective flow, developing in the ablation zone during the ablative acceleration of the laser target plasma. The eigenvalue (instability growth rates) problem is reduced to solving an algebraic equation with the coefficients depending on the unperturbed profile structure of hydrodynamic variables. For the important case of the incompressible plasma subsonic flow, the instability growth rates is shown to vanish at k=k 0 =max(2(g|∇ ln p|) 1/2 /ν). The consistency condition of the model consists in the smallness of the local Froude number in the region of instability development. However, as seen from the comparison with the numerical calculations, the model is well appicable also for the case of the sufficiently abrupt density gradient provided the Froude number is of order of unity
Temporal (In)Stability of Employee Preferences for Rewards
Wine, Byron; Gilroy, Shawn; Hantula, Donald A.
2012-01-01
This study examined the temporal stability of employee preferences for rewards over seven monthly evaluations. Participants completed a ranking stimulus preference assessment monthly, and the latter six monthly assessments were compared to the initial assessment. Correlations of preferences from month to month ranged from r = -0.89 to 0.99.…
Efforts to stabilize the M = 2 helical instability in ATC
International Nuclear Information System (INIS)
Bol, K.; Ellis, R.A. Jr.; Hsuan, H.
1975-01-01
Experiments show that there is no difficulty about interacting with a 2/1 mode in ATC, and that given sufficient gain and a harmonic-free control winding the probability of stabilizing it is good. Control by steadily applied, DC quadrupole fields, on the other hand, on the basis of experiments with ATC as well as Pulsator, would seem at this juncture to have a small chance of success. Finally, the high currents achieved in gettered discharges offer the possibility that if control of wall emission can be achieved--e.g., with a divertor--one may simultaneously achieve a measure of control of the 2/1 and higher modes
Planetary chaos and the (In)stability of Hungaria asteroids
Ćuk, Matija; Nesvorný, David
2018-04-01
The Hungaria asteroid group is located interior to the main asteroid belt, with semimajor axes between 1.8 and 2 AU, low eccentricities and inclinations of 16-35 degrees. Recently, it has been proposed that Hungaria asteroids are a secularly declining population that may be related to the Late Heavy Bombardment (LHB) impactors (Cuk, 2012; Bottke et al., 2012). While Cuk (2012) and Bottke et al. (2012) have reproduced a Hungaria-like population that declined exponentially, the real Hungarias were never confirmed to be unstable to the same degree. Here we find that the stability of Hungarias is strongly dependent on the evolution of the eccentricity of Mars, which is chaotic and unpredictable on Gyr timescales. We find that the high Martian eccentricity chiefly affects Hungarias through close approaches with Mars, rather than planetary secular modes. However, current minimum perihelia of Hungarias (over Myr timescales) are not diagnostic of their long-term stability due to a number of secular and mean motion resonances affecting the Hungaria region Milani et al., 2010. We conclude that planetary chaos makes it impossible to determine the effective lifetimes of observed Hungarias. Furthermore, long-term changes of Martian eccentricity could lead to variable Hungaria loss over time. We speculate that some of the most stable Hungarias may have been placed in their present orbit when the eccentricity of Mars was significantly higher than today.
Stabilizing effect of passive conductors with arbitrary shape for positional instabilities
International Nuclear Information System (INIS)
Seki, Shogo; Ninomiya, Hiromasa; Yoshida, Hidetoshi
1983-10-01
For positional instabilities in the tokamak, the stabilizing index nsub(s) is an adequate parameter to characterize the stabilizing effect produced by several kinds of passive conductors around a plasma column such as vacuum vessel and poloidal field coils. Since a system of passive conductors with arbitrary shape can be involved into multiple L-R circuits, this parameter nsub(s) of those passive conductors is expressed in a simple form by using a method of the eigen mode expansion of multiple L-R circuits. This parameter nsub(s) is very useful to estimate not only a growth rate of positional instability and its feedback stabilization but also an inward shift of plasma column due to a minor disruption. (author)
Strong stabilization of the Rayleigh-Taylor instability by material strength at Mbar pressures
Energy Technology Data Exchange (ETDEWEB)
Park, H S; Lorenz, K T; Cavallo, R M; Pollaine, S M; Prisbrey, S T; Rudd, R E; Becker, R C; Bernier, J V; Remington, B A
2009-11-19
Experimental results showing significant reductions from classical in the Rayleigh-Taylor (RT) instability growth rate due to high pressure effective lattice viscosity are presented. Using a laser created ramped drive, vanadium samples are compressed and accelerated quasi-isentropically at {approx}1 Mbar pressures, while maintaining the sample in the solid-state. Comparisons with simulations and theory indicate that the high pressure, high strain rate conditions trigger a phonon drag mechanism, resulting in the observed high effective lattice viscosity and strong stabilization of the RT instability.
International Nuclear Information System (INIS)
Yasue, Ken-ichi; Asamori, Koichi; Kusano, Tomohiro; Saito-Kokubu, Yoko; Tanikawa, Shin-ichi; Niwa, Masakazu; Hanamuro, Takahiro; Yamasaki, Seiko; Yamada, Kunimi; Ishimaru, Tsuneari; Umeda, Koji
2011-07-01
The concept of geological disposal of HLW in Japan is based on a multi-barrier system which combines a stable geological environment with a robust barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is a plan of research and development (R and D) on geosphere stability for long-term isolation of HLW in JAEA, in fiscal year 2011. The objectives and contents in fiscal year 2011 are described in detail based on the outline of 5 years plan (fiscal years 2010-2014). In addition, the planed framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. (author)
International Nuclear Information System (INIS)
Asamori, Koichi; Niwa, Masakazu; Hanamuro, Takahiro; Yamada, Kunimi; Kusano, Tomohiro; Makuuchi, Ayumu; Takatori, Ryoichi; Saito-Kokubu, Yoko; Ishimaru, Tsuneari; Umeda, Koji
2012-07-01
The concept of geological disposal of HLW in Japan is based on a multi-barrier system which combines a stable geological environment with a robust barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is a plan of research and development (R and D) on geosphere stability for long-term isolation of HLW in JAEA, in fiscal year 2012. The objectives and contents in fiscal year 2012 are described in detail based on the outline of 5 years plan (fiscal years 2010-2014). In addition, the planned framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. (author)
International Nuclear Information System (INIS)
Yasue, Ken-ichi; Asamori, Koichi; Yamada, Kunimi; Saito-Kokubu, Yoko; Yamasaki, Seiko; Kurosawa, Hideki; Tanikawa, Shin-ichi; Negi, Tateyuki; Kusano, Tomohiro; Hanamuro, Takahiro; Ishimaru, Tsuneari; Umeda, Koji
2010-09-01
The concept of geological disposal of HLW in Japan is based on a multibarrier system which combines a stable geological environment with an engineered barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is a plan of research and development (R and D) for geosphere stability for long-term isolation of HLW in JAEA, in fiscal year 2010. The objectives and contents in fiscal year 2010 are described in detail based on the outline of 5 years plan (fiscal years 2010-2014). In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. (author)
Huntington, C. M.; Shimony, A.; Trantham, M.; Kuranz, C. C.; Shvarts, D.; Di Stefano, C. A.; Doss, F. W.; Drake, R. P.; Flippo, K. A.; Kalantar, D. H.; Klein, S. R.; Kline, J. L.; MacLaren, S. A.; Malamud, G.; Miles, A. R.; Prisbrey, S. T.; Raman, K. S.; Remington, B. A.; Robey, H. F.; Wan, W. C.; Park, H.-S.
2018-05-01
The Rayleigh-Taylor (RT) instability is a common occurrence in nature, notably in astrophysical systems like supernovae, where it serves to mix the dense layers of the interior of an exploding star with the low-density stellar wind surrounding it, and in inertial confinement fusion experiments, where it mixes cooler materials with the central hot spot in an imploding capsule and stifles the desired nuclear reactions. In both of these examples, the radiative flux generated by strong shocks in the system may play a role in partially stabilizing RT instabilities. Here, we present experiments performed on the National Ignition Facility, designed to isolate and study the role of radiation and heat conduction from a shock front in the stabilization of hydrodynamic instabilities. By varying the laser power delivered to a shock-tube target with an embedded, unstable interface, the radiative fluxes generated at the shock front could be controlled. We observe decreased RT growth when the shock significantly heats the medium around it, in contrast to a system where the shock did not produce significant heating. Both systems are modeled with a modified set of buoyancy-drag equations accounting for ablative stabilization, and the experimental results are consistent with ablative stabilization when the shock is radiative. This result has important implications for our understanding of astrophysical radiative shocks and supernova radiative hydrodynamics [Kuranz et al., Nature Communications 9(1), 1564 (2018)].
CONSTITUTIONAL ECONOMICS, FISCAL POLICY RULES, ANDTHECASE OF TURKEY
Directory of Open Access Journals (Sweden)
Osman Nuri ARAS
2011-07-01
Full Text Available Discretionary fiscal policies have arisen because of dominant Keynesianeconomic policies from 1930’s to 1970’s. Public expenditures intensively andexcessively increased in order to ensure macroeconomic stability during thisperiod. Many countries faced the emergence of macroeconomic problems such asaffectively using public resources, budget deficitand inflation. As a result,Keynesian economic policies and the stagnation experienced in following highinflation years have faced economies with stagflation process in the 1970’s.However, Keynesian approach did not solve the problem. Therefore, neweconomic approaches developed for solving the problem. One of the neweconomic approaches was Constitutional Economic Theory. The theory includeseconomic policy rules including fiscal rules as well as monetary rules.Fiscal rules have been one of the main stabilization tools in obtaining budget andpublic finance balance. Many countries have implemented specific fiscal policyrules to struggle with economic instabilities, budget deficits and public financialimbalances.A specific form of fiscal policy rule has been started to implement in Turkey since1999. Several fiscal policy rules have been adoptedin Turkey’s public financialmanagement system as part of the economic program which was conducted withthe collaboration of IMF since 1999. These rules are called as implicit fiscalpolicy rules. These fiscal rules have become a draft legal text in 2010 as “FiscalRule Draft Law”. Although the fiscal rule was planned to start the application period as of 2011, it is delayed to fiscal year 2012 because of some economicreasons
International Nuclear Information System (INIS)
Trakhtenberg, A.M.
1987-01-01
A principle possibility of applying the vibrational stabilization method to nuclear reactors is studied. The problem of securing the stability of nuclear reactor operation steady-state regimes is one of the central ones in dynamics theory and nuclear reaction operation experience. In particular, the problem of xenon oscillation suppressing in a reactor, occuring as a result of steady-state regime instability is urgent. Investigation is conducted using the simpliest reactor model, repesenting it as a non-linear object with concentrated parameters. It is proved that vibrational stabilization is achieved by periodic fluctuations of the control rod positions in the reactor core and boric acid concentration in the coolant with period 1s 4 s. In practice stabilization is effective, when the steady-state regime is located near the stability boundary, which appears to be dangerous, i.e. self-oscillations with inadmissibly high amplitude occure in the reactor
Stability and instability on Maya Lowlands tropical hillslope soils
Beach, Timothy; Luzzadder-Beach, Sheryl; Cook, Duncan; Krause, Samantha; Doyle, Colin; Eshleman, Sara; Wells, Greta; Dunning, Nicholas; Brennan, Michael L.; Brokaw, Nicholas; Cortes-Rincon, Marisol; Hammond, Gail; Terry, Richard; Trein, Debora; Ward, Sheila
2018-03-01
Substantial lake core and other evidence shows accelerated soil erosion occurred in the Maya Lowlands of Central America over ancient Maya history from 3000 to 1000 years ago. But we have little evidence of the wider network of the sources and sinks of that eroded sediment cascade. This study begins to solve the mystery of missing soil with new research and a synthesis of existing studies of tropical forest soils along slopes in NW Belize. The research aim is to understand soil formation, long-term human impacts on slopes, and slope stability over time, and explore ecological implications. We studied soils on seven slopes in tropical forest areas that have experienced intensive ancient human impacts and those with little ancient impacts. All of our soil catenas, except for one deforested from old growth two years before, contain evidence for about 1000 years of stable, tropical forest cover since Maya abandonment. We characterized the physical, chemical, and taxonomic characteristics of soils at crest-shoulder, backslopes, footslopes, and depression locations, analyzing typical soil parameters, chemical elements, and carbon isotopes (δ13C) in dated and undated sequences. Four footslopes or depressions in areas of high ancient occupation preserved evidence of buried, clay-textured soils covered by coarser sediment dating from the Maya Classic period. Three footslopes from areas with scant evidence of ancient occupation had little discernable deposition. These findings add to a growing corpus of soil toposequences with similar facies changes in footslopes and depressions that date to the Maya period. Using major elemental concentrations across a range of catenas, we derived a measure (Ca + Mg) / (Al + Fe + Mn) of the relative contributions of autochthonous and allochthonous materials and the relative age of soil catenas. We found very low ratios in clearly older, buried soils in footslopes and depressions and on slopes that had not undergone ancient Maya erosion. We
Passive stabilization of MHD instabilities at high βn in the HBT-EP Tokamak
Energy Technology Data Exchange (ETDEWEB)
Gates, David A. [Columbia Univ., New York, NY (United States)
1993-01-01
The HBT-EP Tokamak has been designed, built, and is now fully operational in the Columbia University Plasma Physics Laboratory. One of the primary purposes of this facility is to study the effects of a conducting wall on the MHD modes that lead up to plasma disruptions. Of particular interest are the types of instabilities that are driven by the kinetic pressure of the plasma, because these instabilities are believed to be responsible for the present limit to plasma β with β ∝/B^{2}, where the is the volume averaged pressure and B is the magnetic field. To this end, a movable conducting wall has been installed inside the HBT-EP vacuum chamber. The primary result of this thesis are the initial results from experiments that study the effect of this wall on plasma instabilities. The experiment shows that the conducting wall significantly reduces the growth rate of instabilities that precede a plasma disruption that occurs when the value of β is near the Troyon limit. The location of the wall required for significant stabilization is b/a ~1.2 where a is the minor radius of the plasma and b is the minor radial location of the wall. Moving the wall closer than b/a = 1.2 slightly degrades the stabilizing effect, which is consistent with recent theories.
Passive stabilization of MHD instabilities at high βn in the HBT-EP Tokamak
International Nuclear Information System (INIS)
Gates, D.A.
1993-01-01
The HBT-EP Tokamak has been designed, built, and is now fully operational in the Columbia University Plasma Physics Laboratory. One of the primary purposes of this facility is to study the effects of a conducting wall on the MHD modes that lead up to plasma disruptions. Of particular interest are the types of instabilities that are driven by the kinetic pressure of the plasma, because these instabilities are believed to be responsible for the present limit to plasma β with β ∝ /B 2 , where the is the volume averaged pressure and B is the magnetic field. To this end, a movable conducting wall has been installed inside the HBT-EP vacuum chamber. The primary result of this thesis are the initial results from experiments that study the effect of this wall on plasma instabilities. The experiment shows that the conducting wall significantly reduces the growth rate of instabilities that precede a plasma disruption that occurs when the value of β is near the Troyon limit. The location of the wall required for significant stabilization is b/a ∼1.2 where a is the minor radius of the plasma and b is the minor radial location of the wall. Moving the wall closer than b/a = 1.2 slightly degrades the stabilizing effect, which is consistent with recent theories
Role of secondary instability theory and parabolized stability equations in transition modeling
El-Hady, Nabil M.; Dinavahi, Surya P.; Chang, Chau-Lyan; Zang, Thomas A.
1993-01-01
In modeling the laminar-turbulent transition region, the designer depends largely on benchmark data from experiments and/or direct numerical simulations that are usually extremely expensive. An understanding of the evolution of the Reynolds stresses, turbulent kinetic energy, and quantifies in the transport equations like the dissipation and production is essential in the modeling process. The secondary instability theory and the parabolized stability equations method are used to calculate these quantities, which are then compared with corresponding quantities calculated from available direct numerical simulation data for the incompressible boundary-layer flow of laminar-turbulent transition conditions. The potential of the secondary instability theory and the parabolized stability equations approach in predicting these quantities is discussed; results indicate that inexpensive data that are useful for transition modeling in the early stages of the transition region can be provided by these tools.
Coherent betatron instability driven by electrostatic separators: Stability analysis of the Tevatron
International Nuclear Information System (INIS)
Harfoush, F.A.; Bogacz, S.A.
1989-03-01
This paper outlines possible intensity limits due to the coherent betatron motion for the upgraded Tevatron with the electrostatic separators. Numerical simulation shows that this new vacuum chamber structure dominates the high frequency part of the coupling impedance spectrum and more likely will excite a slow head-tail instability. A simple stability analysis yields the characteristic growth-time of the unstable modes. 4 refs., 4 figs., 1 tab
Proton-beam propagation through wall-confined plasma channel stabilized against sausage instability
International Nuclear Information System (INIS)
Nakahama, Masao; Nemoto, Masahiro; Masugata, Katsumi; Ito, Michiaki; Matsui, Masao; Yatsui, Kiyoshi
1986-01-01
Experimental results are presented of proton-beam (energy ∼ 650 keV) propagation through wall-confined plasma channel that is stabilized against sausage instability by an externally-applied longitudinal magnetic field. Significant improvement of beam-propagation efficiency has been obtained of ∼ 70 % compared with the previous experiment of ∼ 55 % without the magnetic field. The propagation can also be available up to ∼ 30 % even in a non-propagation region in a non-stabilized channel. (author)
International Nuclear Information System (INIS)
Ishimaru, Tsuneari; Yasue, Kenichi; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Yokoyama, Tatsunori; Fujita, Natsuko; Shimizu, Mayuko; Hama, Yuki
2016-08-01
This report is a plan of research and development (R and D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency, in fiscal year 2016. The objectives and contents in fiscal year 2016 are described in detail based on the outline of 7 years plan (fiscal years 2015-2021). Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. (author)
Kim, Yu Jeong
2017-01-05
Bluff-body flame stabilization has been used as one of main flame stabilization schemes to improve combustion stability in both large and small scale premixed combustion systems. The detailed investigation of instability characteristics is needed to understand flame stability mechanism. Direct numerical simulations are conducted to investigate flame dynamics on the instability of lean premixed hydrogen/air and syngas/air flames stabilized on a meso-scale bluff-body. A two-dimensional channel of 10 mm height and 10 mm length with a square bluff-body stabilizer of 0.5 mm is considered. The height of domain is chosen as an unconfined condition to minimize the effect of the blockage ratio. Flame/flow dynamics are observed by increasing the mean inflow velocity from a steady stable to unsteady asymmetrical instability, followed by blowoff. Detailed observations between hydrogen and syngas flames with a time scale analysis are presented.
International Nuclear Information System (INIS)
Bul'ko, A.B.; Liberman, M.A.
1992-01-01
The authors use the WKB-approximation to treat the problem of the stabilization by an inhomogeneous convective current of the Rayleigh-Taylor instability developing in the ablation zone when the plasma of laser targets is accelerated by ablation. The problem of the eigenvalues - the instability growth rates - is reduced to the solution of an algebraic equation with coefficients which depend on the structure of the unperturbed profiles of the hydrodynamic variables. They show for the practically important case of subsonic flow of an incompressible plasma that the instability growth rate vanishes for k = k o = max[2(g|∇lnρ|) 1/2 /v]. The condition for the self-consistency of the model is that the local Froude number be small in the region where the instability develops; however, comparison with numerical calculations shows that the model is also applicable in the case of rather steep density gradients when the Froude number is of order unity. 32 refs., 2 figs
The theory of stability, bistability, and instability in three-mode class-A lasers
International Nuclear Information System (INIS)
Jahanpanah, J; Rahdar, A A
2014-01-01
Instability is an inevitable and common problem in all different kinds of lasers when they are oscillating in both single-and multi-mode states. Here, the stability conditions are investigated for a three-mode class-A laser. A set of linear equations is derived for the stable oscillation of the cavity central mode together with its left and right adjacent longitudinal modes. The coefficient determinant of stability equations is Hermitian and equal to zero for the roots of two diagonal arrays. In other words, the novelty of our work is to expand the stability coefficient determinant in terms of main diagonal arrays rather than for one row or one column. These diagonal roots lead to two lower and upper boundary curves in the form of a bifurcation. The lower boundary curve mimics the single-mode laser and delimits the instability region (with no above-threshold oscillating mode) from the bistability region (with two above-threshold oscillating modes). The upper boundary curve mimics the two-mode laser and delimits the bistability region from the stability region, in which all three-longitudinal modes are simultaneously oscillating in the above-threshold state. (paper)
Dynamic stabilization of the imploding-shell Rayleigh-Taylor instability
International Nuclear Information System (INIS)
Boris, J.P.
1977-01-01
A method for dynamic stabilization of the Rayleigh-Taylor (R-T) instability on the surface of an imploding fusion pellet is discussed. The driving laser beams are modulated in intensity so the ablation layer is subject to a rapidly and strongly oscillating acceleration. A substantial band of the Rayleigh-Taylor instability spectrum can be stabilized by this oscillation even though the time average acceleration vector lies in the destabilizing direction. By adjusting the frequency, structure, and amplitude of the modulation, the band of dynamically stabilized modes can be made to include the most unstable and dangerous modes. Thus considerably higher aspect ratio shells (i.e., thinner shells) could implode successfully than had been previously considered stable enough. Both theory and numerical simulations support this conclusion for the case of laser-driven pellet implosions. Similar modulation via transverse beam oscillations or parallel bunching should also work to stabilize the most dangerous surface Rayleigh-Taylor modes in relativistic electron-, ion- and heavy ion-pellet fusion schemes. (U.K.)
International Nuclear Information System (INIS)
Kilkenny, J.D.
1994-01-01
As shown elsewhere an ablatively imploded shell is hydrodynamically unstable, the dominant instability being the well known Rayleigh-Taylor instability with growth rate γ = √Akg where k = 2π/λ is the wave number, g is the acceleration and A the Attwood number (ρ hi - ρ lo )/(ρ hi + ρ lo ) where ρ hi is the density of the heavier fluid and ρ lo is the density of the lighter fluid. A theoretical understanding of ablative stabilization has gradually evolved, confirmed over the last five years by experiments. The linear growth is very well understood with excellent agreement between experiment and simulation for planar geometry with wavelengths in the region of 30--100μm. There is an accurate, albeit phenomenological dispersion relation. The non-linear growth has been measured and agrees with calculations. In this lecture, the authors go into the fundamentals of the Rayleigh-Taylor instability and the experimental measurements that show it is stabilized sufficiently by ablation in regimes relevant to ICF
Lee, Nam G; You, Joshua Sung H; Kim, Tae H; Choi, Bong S
2015-02-01
The exact neuromechanical nature and relative contribution of the abdominal drawing-in maneuver (ADIM) to postural instability warrants further investigation in uninjured and injured populations. To determine the effects of the ADIM on static core and unipedal postural stability in nonathletes with core instability. Controlled laboratory study. University research laboratory. A total of 19 nonathletes (4 women: age = 22.3 ± 1.3 years, height = 164.0 ± 1.7 cm, mass = 56.0 ± 4.6 kg; 15 men: age = 24.6 ± 2.8 years, height = 172.6 ± 4.7 cm, mass = 66.8 ± 7.6 kg) with core instability. Participants received ADIM training with visual feedback 20 minutes each day for 7 days each week over a 2-week period. Core instability was determined using a prone formal test and measured by a pressure biofeedback unit. Unipedal postural stability was determined by measuring the center-of-pressure sway and associated changes in the abdominal muscle-thickness ratios. Electromyographic activity was measured concurrently in the external oblique, erector spinae, gluteus medius, vastus medialis oblique, tibialis anterior, and medial gastrocnemius muscles. All participants initially were unable to complete the formal test. However, after the 2-week ADIM training period, all participants were able to reduce the pressure biofeedback unit by a range of 4 to 10 mm Hg from an initial 70 mm Hg and maintain it at 60 to 66 mm Hg with minimal activation of the external oblique (t(18) = 3.691, P = .002) and erector spinae (t(18) = 2.823, P = .01) muscles. Monitoring of the pressure biofeedback unit and other muscle activations confirmed that the correct muscle contraction defining the ADIM was accomplished. This core stabilization was well maintained in the unipedal-stance position, as evidenced by a decrease in the center-of-pressure sway measures (t(18) range, 3.953-5.775, P < .001), an increased muscle-thickness ratio for the transverse abdominis (t(18) = -2.327, P = .03), and a reduction in
Lee, Nam G.; You, Joshua (Sung) H.; Kim, Tae H.; Choi, Bong S.
2015-01-01
Context: The exact neuromechanical nature and relative contribution of the abdominal drawing-in maneuver (ADIM) to postural instability warrants further investigation in uninjured and injured populations. Objective: To determine the effects of the ADIM on static core and unipedal postural stability in nonathletes with core instability. Design: Controlled laboratory study. Setting: University research laboratory. Patients or Other Participants: A total of 19 nonathletes (4 women: age = 22.3 ± 1.3 years, height = 164.0 ± 1.7 cm, mass = 56.0 ± 4.6 kg; 15 men: age = 24.6 ± 2.8 years, height = 172.6 ± 4.7 cm, mass = 66.8 ± 7.6 kg) with core instability. Intervention(s): Participants received ADIM training with visual feedback 20 minutes each day for 7 days each week over a 2-week period. Main Outcome Measures(s): Core instability was determined using a prone formal test and measured by a pressure biofeedback unit. Unipedal postural stability was determined by measuring the center-of-pressure sway and associated changes in the abdominal muscle-thickness ratios. Electromyographic activity was measured concurrently in the external oblique, erector spinae, gluteus medius, vastus medialis oblique, tibialis anterior, and medial gastrocnemius muscles. Results: All participants initially were unable to complete the formal test. However, after the 2-week ADIM training period, all participants were able to reduce the pressure biofeedback unit by a range of 4 to 10 mm Hg from an initial 70 mm Hg and maintain it at 60 to 66 mm Hg with minimal activation of the external oblique (t18 = 3.691, P = .002) and erector spinae (t18 = 2.823, P = .01) muscles. Monitoring of the pressure biofeedback unit and other muscle activations confirmed that the correct muscle contraction defining the ADIM was accomplished. This core stabilization was well maintained in the unipedal-stance position, as evidenced by a decrease in the center-of-pressure sway measures (t18 range, 3.953–5.775, P
Study on Roll Instability Mechanism and Stability Index of Articulated Steering Vehicles
Directory of Open Access Journals (Sweden)
Xuefei Li
2016-01-01
Full Text Available This study examines the roll instability mechanism and stability index of articulated steering vehicles (ASVs by taking wheel loaders as the research object. A seven-degree-of-freedom nonlinear dynamics model of the ASVs is built on the basis of multibody dynamics. A physical prototype model of an ASV is designed and manufactured to validate the dynamic model. Test results reasonably agree with the simulation results, which indicates that the established dynamic model can reasonably describe ASV movements. Detailed analysis of the rollover stability of the wheel loader is performed with the use of the established dynamic model. Analysis results show that rollover will occur when the roll angular velocity exceeds a critical threshold, which is affected by lateral acceleration and slope angle. On this basis, a dynamic stability index applicable to the ASVs is presented.
Active feedback stabilization of the flute instability in a mirror machine using field-aligned coils
International Nuclear Information System (INIS)
Lifshitz, A.; Be'ery, I.; Fisher, A.; Ron, A.; Fruchtman, A.
2012-01-01
A plasma confined in linear mirror machines is unstable even at low β, mainly because of the flute instability. One possible way to stabilize the plasma is to use active feedback to correct the plasma shape in real time. The theoretically investigated apparatus consists of feedback coils aligned with the magnetic field, immersed in a cold plasma around the hot core. When the current through the feedback coils changes, the plasma moves to conserve the magnetic flux via compressional Alfvén waves. An analytical model is used to find a robust feedback algorithm with zero residual currents. It is shown that due to the plasma's rotation, maximal stability is obtained with a large phase angle between the perturbations' modes and the feedback integral-like term. Finally, a two-dimensional MHD simulation implementing the above algorithm in fact shows stabilization of the plasma with zero residual currents. (paper)
International Nuclear Information System (INIS)
Yamamoto, Shunji; Ishii, Shozo; Kawamoto, Shigeshi; Hayashi, Izumi
1981-01-01
Experimental study on the dynamic stabilization of MHD instability with a pinch plasma generator was done, and the results were compared with the theoretical works. The previous results of theoretical analysis showed that a conducting shell worked effectively for the dynamic stabilization of MHD instability. The present experiment was carried out with a linear plasma generator which consisted of a discharge tube, a coil and a conducting shell. The macroscopic behavior of plasma was observed with an image converter camera, and the phenomena due to the instability was measured by a magnetic probe. A sine-cosine coil was employed for the observation of the growth of instability. The following results were obtained. When the frequency of RF current for dynamic stabilization was larger than the growth rate of instability, the experimental results were in agreement with the theoretical ones. The effect of a conducting shell was clearly seen. For the helical instability of short wave length, the dynamic stabilization was easily obtained even without a conducting shell. The self-reversal phenomena due to the helical instability of short wave length was suppressed by the RF current along the axis of a discharge tube. (Kato, T.)
Soft tissue stabilization for palmar midcarpal instability using a palmaris longus tendon graft.
Chaudhry, Tahseen; Shahid, Mohammed; Wu, Feiran; Mishra, Anuj; Deshmukh, Subodh
2015-01-01
To report the results of a technique of soft tissue stabilization for palmar midcarpal instability using a palmaris longus graft. In patients' symptomatic wrists with palmar midcarpal instability that had failed conservative management, we used a dorsal approach and stabilized the hamate and triquetrum by reconstructing the dorsal triquetrohamate ligament. The palmaris longus tendon graft was fixed with bone anchors. Seven wrists in 6 patients were available for follow-up at a mean of 28 months (range, 17-37 mo). There was an overall meaningful improvement in function (mean preoperative Disabilities of the Arm, Shoulder, and Hand score, 49 preoperatively, 28 postoperatively). There was a significant increase in grip strength from 15 to 21 kg. At final follow-up, 2 patients had moderate pain. The others had mild or no pain. Four patients returned to their previous occupation or activity. Patients retained full pronation and supination. When compared with the normal side, flexion was reduced to 71%, extension to 81%, radial deviation to 90%, and ulnar deviation to 65% of the opposite side. Although the mean results show an improvement, one patient had a poor result with deterioration in Disabilities of the Arm, Shoulder, and Hand score in spite of a clinically stable wrist, and another had clinical evidence of recurrent instability during pregnancy. One patient had residual symptoms from a prominent bone anchor. Overall, this technique showed good medium-term results in most of our patients. It retained some midcarpal mobility, eliminated clunking in most patients, and provided a noteworthy improvement in grip strength and function. We continue to use this technique for patients with symptomatic midcarpal instability, but it requires further evaluation with larger patient numbers and a longer follow-up to assess its overall value. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
Stabilization of sausage and kink instability modes of a plasma pinch by radial oscillations
International Nuclear Information System (INIS)
Bud'ko, A.B.; Kravchenko, Y.P.; Liberman, M.A.
1995-01-01
The growth of the global sausage (m=0) and kink (m=1) perturbations of a Z-pinch subject to radial oscillations is considered. It is demonstrated that the oscillations result in significant reduction of the growth rate of both kink and sausage instability modes with wavelengths long compared to the pinch radius. The analysis of stability is carried out in two ways. The first method is based on the averaging magnetohydrodynamic equations over the period of radial oscillations. The second one consists in the analysis of the growth of Fourier-components of perturbations. Numerical simulation demonstrates that even moderate radial oscillations cause reduction of the growth rate of long-wavelength sausage instabilities and complete stabilization of long kinks. This can be understood as a result of the effective gravitational field produced in the pinch by the oscillations. The effect in question can explain the anomalous stability of pinches with respect to the kink perturbations observed in experiments. copyright 1995 American Institute of Physics
Shiravi, Zeinab; Shadmehr, Azadeh; Moghadam, Saeed Talebian; Moghadam, Behrouz Attarbashi
2017-01-01
Many ankle injuries occur while participating in sports that require jumping and landing such as basketball, volleyball and soccer. Most recent studies have investigated dynamic postural stability of patients with chronic ankle instability after landing from a forward jump. The present study aimed to investigate the dynamic postural stability of the athletes who suffer from chronic ankle sprain while landing from a lateral jump. Twelve athletes with self-reported unilateral chronic ankle instability (4 females and 8 males) and 12 matched controls (3 females and 9 males) voluntarily participated in the study. Dynamic postural stability index and its directional indices were measured while performing lateral jump landing test. No differences were found between athletes with and without chronic ankle instability during our landing protocol by means of the dynamic postural stability index and its directional indices. Findings showed that in each group, medial/lateral stability index is significantly higher than anterior/posterior and vertical stability indexes. Findings showed that dynamic postural stability was not significantly different between the two groups. Future studies should examine chronic ankle instability patients with more severe disabilities and expose them to more challenging dynamic balance conditions to further explore postural stability. IIIa.
Resistive instabilities in reversed shear discharges and wall stabilization on JT-60U
International Nuclear Information System (INIS)
Takeji, S.; Tokuda, S.; Fujita, T.; Suzuki, T.; Isayama, A.; Ide, S.; Ishii, Y.; Kamada, Y.; Koide, Y.; Matsumoto, T.; Oikawa, T.; Ozeki, T.; Sakamoto, Y.
2001-01-01
Resistive instabilities and wall stabilization of ideal low toroidal mode number, n, kink modes are investigated in JT-60U reversed shear discharges. Resistive interchange modes with n=1 are found to appear in reversed shear discharges with large pressure gradient at the normalized beta, β N , of about unity or even lower. The resistive interchange modes appear as intermittent burst-like magnetohydrodynamic (MHD) activities and higher n≤3 modes are observed occasionally in higher β N regime. No clear degradation of the plasma stored energy is observed by the resistive interchange modes themselves. It is also found that resistive interchange modes can lead to major collapse owing to a coupling with tearing modes at the outer mode rational surface over the minimum safety factor. Stability analysis revealed that stability parameter of tearing modes, Δ' , at the outer mode rational surface is affected by the free-boundary condition. The result is consistent with the experimental evidence that major collapse tends to occur when plasma edge safety factor, q*, is near integer values. Stabilization of ideal low n kink modes by the JT-60U wall is demonstrated. Magnetohydrodynamic perturbations that are attributed to resistive wall modes are observed followed by major collapse in wall-stabilized discharges. (author)
Stability of an expanding cylindrical plasma envelope: Rayleigh--Taylor instability
International Nuclear Information System (INIS)
Han, S.J.
1982-01-01
The stability of a cylindrically symmetric plasma envelope driven outward by blast waves is considered. The plasma fluid is assumed to be a compressible, isentropic gas describable as an ideal gas ( p = arho/sup γ/, γ>1). The stability problem of such an envelope undergoing self-similar motion is solved by considering the initial-value problem. It is shown that in the early phase of an expansion, the envelope is unstable to Rayleigh--Taylor modes which develop at the inner surface. In the later phase of the expansion, the Rayleigh--Taylor modes are weakened due to the geometrical divergence effect. The implications of the time-dependent behavior of the Rayleigh--Taylor instability for plasma switches are discussed
Directory of Open Access Journals (Sweden)
Tahereh Pourkhani
2017-07-01
Conclusion In the athletes with chronic ankle instability, taping without fatigue improved dynamic balance in the vertical direction. Taping after fatigue could not improve dynamic stability in the athletes with and without chronic ankle instability. Future researchers should examine injured and uninjured participants tested under these conditions to determine if these results are useful in selecting appropriate prophylactic method that can treat or prevent injury to the ankle during functional activities.
International Nuclear Information System (INIS)
Paul, Subhanker; Singh, Suneet
2015-01-01
The prime objective of the presented work is to develop a Nodalized Reduced Order Model (NROM) to carry linear stability analysis of flow instabilities in a two-phase flow system. The model is developed by dividing the single phase and two-phase region of a uniformly heated channel into N number of nodes followed by time dependent spatial linear approximations for single phase enthalpy and two-phase quality between the consecutive nodes. Moving boundary scheme has been adopted in the model, where all the node boundaries vary with time due to the variation of boiling boundary inside the heated channel. Using a state space approach, the instability thresholds are delineated by stability maps plotted in parameter planes of phase change number (N pch ) and subcooling number (N sub ). The prime feature of the present model is that, though the model equations are simpler due to presence of linear-linear approximations for single phase enthalpy and two-phase quality, yet the results are in good agreement with the existing models (Karve [33]; Dokhane [34]) where the model equations run for several pages and experimental data (Solberg [41]). Unlike the existing ROMs, different two-phase friction factor multiplier correlations have been incorporated in the model. The applicability of various two-phase friction factor multipliers and their effects on stability behaviour have been depicted by carrying a comparative study. It is also observed that the Friedel model for friction factor calculations produces the most accurate results with respect to the available experimental data. (authors)
International Nuclear Information System (INIS)
Gordeev, Alexander V.
2002-01-01
The stabilization of the Rayleigh-Taylor instability for the imploding cylindrical liner in the limit of a low plasma density Π ω pi 2 δ2/c2 << 1 (δ -- the characteristic size of the current layer) is investigated, when the electron currents are much greater than the ion currents. The stabilization of the Rayleigh-Taylor instability for the parameter diapason νii/ωBi < (Z2M/m)1/2 is considered, when the plasma dissipation connected with the ion-ion collisions considerably superior the usual dissipation due to the electron-ion collisions. For the electric conductivity, caused by the ion-ion collisions and resulted in the minimum value σ ∼ enc/B, the effect of the partial stabilization of the Rayleigh-Taylor instability is demonstrated
Directory of Open Access Journals (Sweden)
Abdurrahman TARAKTAŞ
2017-12-01
Full Text Available Fiscal drag is a result of real or nominal expanding economy and progressive taxation. In general, individuals are forced to enter the upper tax bracket depending on their increased income or expenditure. More tax burden can result in less consumption. Fiscal drag, lack of spending or excessive taxation can cause the economy to slow down. Traditional view suggests that fiscal drag may serve as a natural automatic stabilizer to cool the economy. However, this view ignores the supply side and in particular the potential effects of the high tax burden on economy. This study examines the extent to which the expected automatic stabilization function can be performed and the possible side effects on economic balances and income distribution of fiscal drag in our country in the case of new regulation with price criteria in automotive sectors Special Consumption Tax (SCT.
International Nuclear Information System (INIS)
Itasse, Maxime; Brazier, Jean-Philippe; Léon, Olivier; Casalis, Grégoire
2015-01-01
Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m 1 , n 1 ), (m 2 , n 2 ), such that the difference in azimuth and in frequency matches the desired “target” mode (m 1 − m 2 , n 1 − n 2 ). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes
Energy Technology Data Exchange (ETDEWEB)
Itasse, Maxime, E-mail: Maxime.Itasse@onera.fr; Brazier, Jean-Philippe, E-mail: Jean-Philippe.Brazier@onera.fr; Léon, Olivier, E-mail: Olivier.Leon@onera.fr; Casalis, Grégoire, E-mail: Gregoire.Casalis@onera.fr [Onera - The French Aerospace Lab, F-31055 Toulouse (France)
2015-08-15
Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m{sub 1}, n{sub 1}), (m{sub 2}, n{sub 2}), such that the difference in azimuth and in frequency matches the desired “target” mode (m{sub 1} − m{sub 2}, n{sub 1} − n{sub 2}). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes.
Passive control of thermoacoustic instabilities in swirl-stabilized combustion at elevated pressures
Directory of Open Access Journals (Sweden)
L Justin Williams
2016-09-01
Full Text Available In this study, a porous insert is placed at the dump plane of a swirl-stabilized lean premixed combustor to passively suppress thermoacoustic instabilities. The diffuser-shaped annular ring of porous inert material influences the turbulent flow field directly, including recirculation zones and vortical and/or shear layer structures to passively control the acoustic performance of the combustor. The porous inert material is made of silicon carbide–hafnium carbide coated, high-strength, high-temperature-resistant open-cell foam materials. In this study, the porous insert concept is investigated at above-ambient operating pressures to demonstrate its suitability for practical combustion applications. Experiments are conducted in quartz and metal combustors, without and with the porous insert while varying operating pressure, equivalence ratio, and reactant flow rate. Measurements show that the porous insert, and consequent changes in the combustor flow field, decrease the sound pressure levels at the frequency of combustion instability at all operating conditions investigated in this study. The porous insert also decreases the broadband combustion noise, i.e. the measured sound pressure levels over a wide frequency range.
The effect of crack instability/stability on fracture toughness of brittle materials
International Nuclear Information System (INIS)
Baratta, F.I.
1997-01-01
This paper summarizes three recent experimental works coauthored by the present author regarding the effect of crack instability/stability on fracture toughness, and also includes the necessary formulae for predicting stability. Two recent works have shown that unstable crack extension resulted in apparent increases in fracture toughness compared to that determined during stable crack growth. In the first investigation a quasi-brittle polymer, polymethylmethacrylate, was examined. In the second, a more brittle metallic material, tungsten, was tested. In both cases the transition from unstable to stable behavior was predicted based on stability analyses. The third investigation was conducted on a truly brittle ceramic material, hot pressed silicon nitride. These three papers showed that fracture toughness test results conducted on brittle materials vary according to whether the material fractures in an unstable or stable manner. Suggestions for achieving this important yet difficult phenomenon of stable crack growth, which is necessary when determining the fracture toughness variation occurring during unstable/stable crack advance, are presented, as well as recommendations for further research
Groenendijk, Nico; Donnelly, Shawn
2012-01-01
After its first thorough revision in 2005, the Stability & Growth Pact (SGP) has recently been transformed into a Fiscal Stability Treaty, which in all likelihood will become operational as from January 1, 2013. Part of this treaty is the incorporation of balanced budget rules into domestic
International Nuclear Information System (INIS)
Ogasawara, Masatada; Takita, Masami.
1981-08-01
Spontaneous magnetic fields due to the temperature gradient nabla T 0 produced by a focussed laser beam on one point of a pellet are taken into account in deriving the dispersion relation of Rayleigh-Taylor instability. Growth rate γ decreases with time. Density fluctuation with wavelength shorter than 1.5(R/L sub(T)) x (n sub(s)/n 0 )sup(1/2) μm is remarkably stabilized, where R, L sub(T), n sub(s) and n 0 are the radius of a pellet, L sub(T)sup(-1) = + nabla T 0 /T 0 + , number densities of solid and the pellet. Validity condition of the theory is γt 0 >> 1 or in another form R >> L, where t 0 is the time of thermal expansion of a pellet and L -1 = + nabla n 0 /n 0 + . (author)
Stabilization of ablative Rayleigh-Taylor instability due to change of the Atwood number
International Nuclear Information System (INIS)
Ye Wenhua; He, X.T.; Zhang Weiyan
2002-01-01
Recent experiment [S.G. Glendinning et al., Phys. Rev. Lett. 78, 3318 (1997)] showed that the measured growth rate of laser ablative Rayleigh-Taylor (RT) instability with preheating is about 50% of the classic value and is reduced by about 18% compared with the simulated value obtained with the computer code LASNEX. By changing the temperature variation of the electron thermal conductivity at low temperatures, the density profile from the Bhatnagar-Gross-Krook approximation is recovered in the simulation, and the simulated RT growth rate is in good agreement with the experimental value from Glendinning et al. The preheated density profile on ablative RT stablization is studied numerically. A change of the Atwood number in the preheating case also leads to RT stabilization. The RT growth formula γ=√(Akg/(1+AkL))-2kV a agrees well with experiment and simulation, and is appropriate for the preheating case
Alterman, B. L.; Klein, K. G.; Verscharen, D.; Stevens, M. L.; Kasper, J. C.
2017-12-01
Long duration, in situ data sets enable large-scale statistical analysis of free-energy-driven instabilities in the solar wind. The plasma beta and temperature anisotropy plane provides a well-defined parameter space in which a single-fluid plasma's stability can be represented. Because this reduced parameter space can only represent instability thresholds due to the free energy of one ion species - typically the bulk protons - the true impact of instabilities on the solar wind is under estimated. Nyquist's instability criterion allows us to systematically account for other sources of free energy including beams, drifts, and additional temperature anisotropies. Utilizing over 20 years of Wind Faraday cup and magnetic field observations, we have resolved the bulk parameters for three ion populations: the bulk protons, beam protons, and alpha particles. Applying Nyquist's criterion, we calculate the number of linearly growing modes supported by each spectrum and provide a more nuanced consideration of solar wind stability. Using collisional age measurements, we predict the stability of the solar wind close to the sun. Accounting for the free-energy from the three most common ion populations in the solar wind, our approach provides a more complete characterization of solar wind stability.
DEFF Research Database (Denmark)
Boesen, Morten P; Jensen, Tim Toftgaard; Husted, Henrik
2004-01-01
A case of a fractured polyethylene stabilizing insert causing secondary knee instability in a Dual-articular total knee arthroplasty (TKA) is presented. A 65-year-old woman who underwent surgery with a Dual-articular TKA 4 years earlier had a well-functioning prosthesis until a fall, after which......-articular knee....
International Nuclear Information System (INIS)
Sotnikov, V.I.; Paraschiv, I.; Makhin, V.; Bauer, B.S.; Leboeuf, J.N.; Dawson, J.M.
2002-01-01
A systematic study of the linear stage of sheared flow stabilization of Z-pinch plasmas based on the Hall fluid model with equilibrium that contains sheared flow and an axial magnetic field is presented. In the study we begin with the derivation of a general set of equations that permits the evaluation of the combined effect of sheared flow and axial magnetic field on the development of the azimuthal mode number m=0 sausage and m=1 kink magnetohydrodynamic (MHD) instabilities, with the Hall term included in the model. The incorporation of sheared flow, axial magnetic field, and the Hall term allows the Z-pinch system to be taken away from the region in parameter space where ideal MHD is applicable to a regime where nonideal effects tend to govern stability. The problem is then treated numerically by following the linear development in time of an initial perturbation. The numerical results for linear growth rates as a function of axial sheared flow, an axial magnetic field, and the Hall term are reported
International Nuclear Information System (INIS)
Yasue, Ken-ichi; Asamori, Koichi; Niwa, Masakazu; Hanamuro, Takahiro; Saito-Kokubu, Yoko; Sueoka, Shigeru; Makuuchi, Ayumu; Ikuta, Masafumi; Matsubara, Akihiro; Tamura, Hajimu; Kobori, Kazuo; Ishimaru, Tsuneari; Umeda, Koji
2014-03-01
This annual report documents the progress of R and D in the 3rd fiscal year during the JAEA 2nd Midterm Plan (FY 2010 - 2014) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned framework is structured into the following categories: 1) development and systematization of investigation techniques for selecting suitable sites in geosphere stability, 2) development, application and verification of prediction models for evaluating the changes of geological environment in thermal, hydraulic, mechanical and geochemical conditions for a long period of time, and 3) development of new dating techniques for providing information about geologic history and the timing of geologic events. In this report, the current status of R and D activities with previous scientific and technological progress is summarized. (author)
International Nuclear Information System (INIS)
Madarame, Haruki; Okamoto, Koji; Iida, Masao
1997-03-01
Various nonlinear behaviors caused by nonlinear boundary conditions have been observed, and it is feared that in large vessels like FBRs, the instability phenomena such as self-exciting sloshing may occur in the free liquid surface of coolant. In this research, the nonlinear instability phenomena in free liquid surface were examined by the basic experiment and the analysis. As to the self-exciting oscillation 'jet flutter' of upward plane jet that collides against liquid surface, in order to know the mechanism of determining the frequency and supplying energy, the amplitude and phase relation of various variable quantities were investigated. The simplified model for calculating the displacement of jet was made, and compared with the experiment. The jet flutter phenomena are explained. The interaction of free liquid surface and turbulent flow, which is important for considering the nonlinearity in free liquid surface, was measured by LDV and visualization, and the turbulent flow phenomena in free liquid surface were investigated. In the experiment, turbulent flow energy was given to the free liquid surfaces of water and polymers, and the effect that the Toms effect exerted to interface turbulent flow was observed. The results of these studies are reported. (K.I.) studies are reported. (K.I.)
Directory of Open Access Journals (Sweden)
DARIUSZ ELIGIUSZ STASZCZAK
2015-03-01
Full Text Available This paper analyses reasons of the instability of the world monetary system. The author considers this problem from historical and contemporary perspectives. According to presented point of view banknotes and electronic money which replaced gold and silver coins in popular circulation are the most important reason of the instability. There are also proven positive and negative consequences of money instability. Reforms of the world monetary system need agreement within the global collective hegemony of state-powers and transnational corporations.
Phadnis, Joideep; Arnold, Christine; Elmorsy, Ahmed; Flannery, Mark
2015-08-01
The redislocation rate after arthroscopic stabilization for anterior glenohumeral instability is up to 30%. The Instability Severity Index Score (ISIS) was developed to preoperatively rationalize the risk of failure, but it has not yet been validated by an independent group. To assess the utility of the ISIS in predicting failure of arthroscopic anterior shoulder stabilization and to identify other preoperative factors for failure. Case-control study; Level of evidence, 3. A case-control study was performed on 141 consecutive patients, comparing those who suffered failure of arthroscopic stabilization with those who had successful arthroscopic stabilization. The mean follow-up time was 47 months (range, 24-132 months). The ISIS was applied retrospectively, and an analysis was performed to establish independent risk factors for failure. A receiver operator coefficient curve was constructed to set a threshold ISIS for considering alternative surgery. Of 141 patients, 19 (13.5%) suffered recurrent instability. The mean ISIS of the failed stabilization group was higher than that of the successful stabilization group (5.1 vs 1.7; P surgery (P < .001), age at first dislocation (P = .01), competitive-level participation in sports (P < .001), and participation in contact or overhead sports (P = .03). The presence of glenoid bone loss carried the highest risk of failure (70%). There was a 70% risk of failure if the ISIS was ≥4, as opposed to a 4% risk of failure if the ISIS was <4. This is the first completely independent study to confirm that the ISIS is a useful preoperative tool. It is recommended that surgeons consider alternative forms of stabilization if the ISIS is ≥4. © 2015 The Author(s).
Taamallah, Soufien
2014-06-16
In this paper, we conduct an experimental investigation of a confined premixed swirl-stabilized dump combustor similar to those found in modern gas turbines. We operate the combustor with premixed methane-air in the lean range of equivalence ratio ϕ ∈ [0.5–0.75]. First, we observe different dynamic modes in the lean operating range, as the equivalence ratio is raised, confirming observations made previously in a similar combustor geometry but with a different fuel [1]. Next we examine the correspondence between dynamic mode transitions and changes in the mean flame configuration or macrostructure. We show that each dynamic mode is associated with a specific flame macrostructure. By modifying the combustor length without changing the underlying flow, the resonant frequencies of the geometry are altered allowing for decoupling the heat release fluctuations and the acoustic field, in a certain range of equivalence ratio. Mean flame configurations in the modified (short) combustor and for the same range of equivalence ratio are examined. It is found that not only the same sequence of flame configurations is observed in both combustors (long and short) but also that the set of equivalence ratio where transitions in the flame configuration occur is closely related to the onset of thermo-acoustic instabilities. For both combustor lengths, the flame structure changes at similar equivalence ratio whether thermo-acoustic coupling is allowed or not, suggesting that the flame configuration holds the key to understanding the onset of self-excited thermo-acoustic instability in this range. Finally, we focus on the flame configuration transition that was correlated with the onset of the first dynamically unstable mode ϕ ∈ [0.61–0.64]. Our analysis of this transition in the short, uncoupled combustor shows that it is associated with an intermittent appearance of a flame in the outer recirculation zone (ORZ). The spectral analysis of this “ORZ flame flickering”
Taamallah, Soufien; LaBry, Zachary A.; Shanbhogue, Santosh J.; Ghoniem, Ahmed F.
2014-01-01
In this paper, we conduct an experimental investigation of a confined premixed swirl-stabilized dump combustor similar to those found in modern gas turbines. We operate the combustor with premixed methane-air in the lean range of equivalence ratio ϕ ∈ [0.5–0.75]. First, we observe different dynamic modes in the lean operating range, as the equivalence ratio is raised, confirming observations made previously in a similar combustor geometry but with a different fuel [1]. Next we examine the correspondence between dynamic mode transitions and changes in the mean flame configuration or macrostructure. We show that each dynamic mode is associated with a specific flame macrostructure. By modifying the combustor length without changing the underlying flow, the resonant frequencies of the geometry are altered allowing for decoupling the heat release fluctuations and the acoustic field, in a certain range of equivalence ratio. Mean flame configurations in the modified (short) combustor and for the same range of equivalence ratio are examined. It is found that not only the same sequence of flame configurations is observed in both combustors (long and short) but also that the set of equivalence ratio where transitions in the flame configuration occur is closely related to the onset of thermo-acoustic instabilities. For both combustor lengths, the flame structure changes at similar equivalence ratio whether thermo-acoustic coupling is allowed or not, suggesting that the flame configuration holds the key to understanding the onset of self-excited thermo-acoustic instability in this range. Finally, we focus on the flame configuration transition that was correlated with the onset of the first dynamically unstable mode ϕ ∈ [0.61–0.64]. Our analysis of this transition in the short, uncoupled combustor shows that it is associated with an intermittent appearance of a flame in the outer recirculation zone (ORZ). The spectral analysis of this “ORZ flame flickering”
Shahnazari, M. R.; Maleka Ashtiani, I.; Saberi, A.
2018-03-01
In this paper, the effect of channeling on viscous fingering instability of miscible displacement in porous media is studied. In fact, channeling is introduced as a solution to stabilize the viscous fingering instability. In this solution, narrow channels were placed next to the walls, and by considering an exponential function to model the channeling effect, a heterogeneous media is assumed. In linear stability analysis, the governing equations are transferred to Fourier space, and by introducing a novel numerical method, the transferred equations are analyzed. The growth rate based on the wave number diagram has been drawn up in three sections of the medium. It is found that the flow becomes more stable at the center and unstable along the walls when the permeability ratio is increased. Also when the permeability ratio is approximately equal to one, the channeling has no significant effect. In nonlinear simulations, by using stream function and vortices, new equations have been rewritten and it is shown that channeling has a profound effect on the growth of the fingers and mechanisms. In addition to the superposition of velocity vectors and concentration contours, the development of instability is investigated using the mixing length and sweep efficiency diagram. The results show that although channeling reduces instability, it increases the displacement process time.
Energy Technology Data Exchange (ETDEWEB)
Tare, U. A.; Mody, F. K.; Mese, A. I. [Haliburton Energy Services, TX (United States)
2002-07-01
In order to develop a real-time wellbore (in)stability modelling capability, experimental work was carried out to investigate the role of the chemical potential of drilling fluids on transient pore pressure and time-dependent rock property alterations of shale formations. Time-dependent alterations in the pore pressure, acoustic and rock properties of formations subjected to compressive tri-axial test were recorded during the experiments involving the Pore Pressure Transmission (PPT) test. Based on the transient pore pressure of shale exposed to the test fluid presented here, the 20 per cent calcium chloride showed a very low membrane efficiency of 4.45 per cent. The need for a thorough understanding of the drilling fluid/shale interaction prior to applying any chemical potential wellbore (in)stability model to real-time drilling operations was emphasized. 9 refs., 5 figs.
Hardin, G. R.; Sani, R. L.; Henry, D.; Roux, B.
1990-01-01
The buoyancy-driven instability of a monocomponent or binary fluid completely contained in a vertical circular cylinder is investigated, including the influence of the Soret effect for the binary mixture. The Boussinesq approximation is used, and the resulting linear stability problem is solved using a Galerkin technique. The analysis considers fluid mixtures ranging from gases to liquid metals. The flow structure is found to depend strongly on both the cylinder aspect ratio and the magnitude of the Soret effect. The predicted stability limits are shown to agree closely with experimental observations.
International Nuclear Information System (INIS)
Kilkenny, J.D.; Glendinning, S.G.; Haan, S.W.
1993-12-01
It has been recognized for many year's that the most significant limitation of ICF is the Rayleigh-Taylor (R-T) instability. It limits the distance an ablatively driven shell can be moved to several times its initial thickness. Fortunately material flow through the unstable region at velocity v A reduces the growth rate to √ 1+kL / kg -βkv A with β from 2-3. In recent years experiments using both x-ray drive and smoothed laser drive to accelerate foils have confirmed our understanding of the ablative R-T instability in planar geometry. The growth of small initial modulations on the foils is measured for growth factors up to 60 for direct drive and 80 for indirect drive. For x-ray drive large stabilization is evident. After some growth, the instability enters the non-linear phase when mode coupling and saturation are also seen and compare well with modeling. Normalized growth rates for direct drive are measured to be higher, but strategies for reduction by raising the isentrope are being investigated. For direct drive, high spatial frequencies are imprinted from the laser beam and amplified by the R-T instability. Modeling shows an understanding of this ''laser imprinting.''
A review of the ablative stabilization of the Rayleigh-Taylor instability in regimes relevant to ICF
International Nuclear Information System (INIS)
Kilkenny, J.D.; Glendinning, S.G.; Haan, S.W.; Hammel, B.A.; Lindl, J.D.; Munro, D.; Remington, B.A.; Weber, S.V.; Knauer, J.P.; Verdon, C.P.
1993-12-01
It has been recognized for many years that the most significant limitation of ICF is the Rayleigh-Taylor (R-T) instability. It limits the distance an ablatively driven shell can be moved to several times its initial thickness. Fortunately material flow through the unstable region at velocity v A reduces the growth rate to √ 1+kL / kg -βkv A with β from 2-3. In recent years experiments using both x-ray drive and smoothed laser drive to accelerate foils have confirmed our understanding of the R-T instability. The growth of small initial modulations on the foils is measured for growth factors up to 60 for direct drive and 80 for indirect drive. For x-ray drive large stabilization is evident After some growth, the instability enters the non-linear phase when mode coupling and saturation are also seen and compare well with modeling. Normalized growth rates for direct drive are measured to be higher, but strategies for reduction by raising the isentrope are being investigated. For direct drive, high spatial frequencies are imprinted from the laser beam and amplified by the R-T instability. Modeling shows an understanding of this ''laser imprinting.''
POWER STABILITY MONITORING BASED ON VOLTAGE INSTABILITY PREDICTION APPROACH THROUGH WIDE AREA SYSTEM
H. H. Goh; Q. S. Chua; S. W. Lee; B. C. Kok; K. C. Goh; K. T.K. Teo
2014-01-01
Nowadays, power systems are being forced to operate closer to its security limit due to current economic growth and the difficulties to upgrade the existing grid infrastructure. With the sudden increment of power demand, voltage instability problem has become a main concern to the power system operator because voltage instability has led or crucially contributed to some major blackouts throughout the world. Hence, methods for early warning and early prevention are required to prevent the powe...
International Nuclear Information System (INIS)
Du Chaohai; Liu Pukun
2009-01-01
The problem of spurious oscillations induced by absolute instabilities is the most challenging one that hinders the development of the millimeter-wave gyrotron traveling-wave amplifiers (gyro-TWTs). A spurious oscillation exists as a high order axial mode (HOAM) in the interaction circuit. This paper is devoted to demonstrating the complicated steady states of these HOAMs and exploring corresponding techniques to stabilize these potential multi-steady-state absolute instabilities. The stability-oriented design principle is conveyed in a start-to-end design flow of a Ka-band TE 11 mode gyro-TWT. Strong magnetic tapering near the downstream port, which is capable of cutting short the effective interaction circuit of a spurious oscillation and simultaneously boosting the amplification performance, is for the first time proposed to further improve the system stability. It is also found that an ideal prebunched electron beam in the linear stage is the necessary condition to efficient amplification in the nonlinear stage, suggesting that it is feasible to design a stable prebunching stage to replace the distributed-loss-loaded linear stage. The stability-oriented design principle provides more explicit reference for future design of a zero-drive stable gyro-TWT.
Schmalzried, Hans D; Fallon, L Fleming
2013-01-01
Major funding cuts have occurred throughout the United States public health system during the past several years. Funding for local public health agency (LPHA) services and programs is obtained through a patchwork of sources that vary both within and among states. Even though local city and county sources provide a significant proportion of funding for LPHAs, information available in the literature about these revenues is sparse and is not clearly described. This study focused on a single specific revenue stream included in the local sources (local city and county) category: funds voted on directly by the public. The primary purpose of this study was to examine whether this type of funding source provided fiscal advantages for LPHAs. Specifically, we wanted to see how sensitive levy votes were to changing general economic conditions. A questionnaire to collect LPHA levy data was developed, approved, and mailed to county boards of elections in Ohio (n = 88). Elections officials were asked to provide voting results for all LPHA levy ballot attempts since 1994 regardless of outcome. In the study period (1994 through 2011), 250 LPHA property tax levies were placed on election ballots in Ohio. LPHAs were successful in 155 (62.0%) and unsuccessful in 95 (38.0%) attempts. Over the 18-year period, the most noteworthy outcome was a 94.6% pass rate for renewal levies. Our study demonstrated that voter-approved tax levies provide some fiscal advantages for LPHAs: higher per capita revenues than those who have to rely on other sources of income and predictable revenue streams. This translates into more funds being available for public health programs and services. Property tax levies allow citizens to make direct investments in their local health departments.
International Nuclear Information System (INIS)
Umeda, Koji; Ishimaru, Tsuneari; Yasue, Ken-ichi; Asamori, Koichi; Yamada, Kunimi; Saito-Kokubu, Yoko; Hanamuro, Takahiro; Tanikawa, Shin-ichi; Kusano, Tomohiro
2010-09-01
The concept of geological disposal of HLW in Japan is based on a multibarrier system which combines a stable geological environment with an engineered barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is to outline 5 years plan (fiscal years 2010-2014) of research and development (R and D) for geosphere stability for long-term isolation of the high-level radioactive waste in JAEA. Background of this research are clarified with the necessity and the significance, and the past progresses in this report. The objectives, outline, contents and schedule during the next 5 years are described in detail. In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. (author)
International Nuclear Information System (INIS)
Umeda, Koji; Yasue, Ken-ichi; Saito-Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Fujita, Natsuko; Shimizu, Mayuko; Shimada, Akiomi; Matsubara, Akihiro; Tamura, Hajimu; Yokoyama, Tatsunori; Watanabe, Takahiro; Tokuyasu, Kayoko; Hama, Yuki
2015-08-01
The study on long-term geological stability has three objectives, namely, (1) development of technologies for determining the past and present conditions of the geological environment, (2) development of technologies for long-term prediction and evaluation of impacts and (3) development of dating techniques using advanced equipment on isotope geology and geochronology, in order to make contribution to site investigation and safety assessment for the geological disposal of high-level radioactive waste (HLW). This report is to outline 7 years plan (fiscal years 2015-2021) of research and development (R and D) for geosphere stability for long-term isolation of the HLW in Japan Atomic Energy Agency. Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. The objectives, outline, contents and schedule during the next 7 years are described in detail. In addition, the plan framework is structured into the following categories: (1) Development and Systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. (author)
DEFF Research Database (Denmark)
Göksu, Ömer; Teodorescu, Remus; Bak, Claus Leth
2014-01-01
In recent grid codes for wind power integration, wind turbines are required to stay connected during grid faults even when the grid voltage drops down to zero; and also to inject reactive current in proportion to the voltage drop. However, a physical fact, instability of grid-connected converters...... during current injection to very low (close to zero) voltage faults, has been omitted, i.e., failed to be noticed in the previous wind power studies and grid code revisions. In this paper, the instability of grid side converters of wind turbines defined as loss of synchronism (LOS), where the wind...... turbines lose synchronism with the grid fundamental frequency (e.g., 50 Hz) during very deep voltage sags, is explored with its theory, analyzed and a novel stability solution based on PLL frequency is proposed; and both are verified with power system simulations and by experiments on a grid...
Directory of Open Access Journals (Sweden)
Melissa C Kilby
Full Text Available Falls among the older population can severely restrict their functional mobility and even cause death. Therefore, it is crucial to understand the mechanisms and conditions that cause falls, for which it is important to develop a predictive model of falls. One critical quantity for postural instability detection and prediction is the instantaneous stability of quiet upright stance based on motion data. However, well-established measures in the field of motor control that quantify overall postural stability using center-of-pressure (COP or center-of-mass (COM fluctuations are inadequate predictors of instantaneous stability. For this reason, 2D COP/COM virtual-time-to-contact (VTC is investigated to detect the postural stability deficits of healthy older people compared to young adults. VTC predicts the temporal safety margin to the functional stability boundary ( = limits of the region of feasible COP or COM displacement and, therefore, provides an index of the risk of losing postural stability. The spatial directions with increased instability were also determined using quantities of VTC that have not previously been considered. Further, Lempel-Ziv-Complexity (LZC, a measure suitable for on-line monitoring of stability/instability, was applied to explore the temporal structure or complexity of VTC and the predictability of future postural instability based on previous behavior. These features were examined as a function of age, vision and different load weighting on the legs. The primary findings showed that for old adults the stability boundary was contracted and VTC reduced. Furthermore, the complexity decreased with aging and the direction with highest postural instability also changed in aging compared to the young adults. The findings reveal the sensitivity of the time dependent properties of 2D VTC to the detection of postural instability in aging, availability of visual information and postural stance and potential applicability as a
Mukherjee, Rabibrata; Das, Soma; Das, Anindya; Sharma, Satinder K; Raychaudhuri, Arup K; Sharma, Ashutosh
2010-07-27
We investigate the influence of gold nanoparticle addition on the stability, dewetting, and pattern formation in ultrathin polymer-nanoparticle (NP) composite films by examining the length and time scales of instability, morphology, and dynamics of dewetting. For these 10-50 nm thick (h) polystyrene (PS) thin films containing uncapped gold nanoparticles (diameter approximately 3-4 nm), transitions from complete dewetting to arrested dewetting to absolute stability were observed depending on the concentration of the particles. Experiments show the existence of three distinct stability regimes: regime 1, complete dewetting leading to droplet formation for nanoparticle concentration of 2% (w/w) or below; regime 2, partial dewetting leading to formation of arrested holes for NP concentrations in the range of 3-6%; and regime 3, complete inhibition of dewetting for NP concentrations of 7% and above. Major results are (a) length scale of instability, where lambdaH approximately hn remains unchanged with NP concentration in regime 1 (n approximately 2) but increases in regime 2 with a change in the scaling relation (n approximately 3-3.5); (b) dynamics of instability and dewetting becomes progressively sluggish with an increase in the NP concentration; (c) there are distinct regimes of dewetting velocity at low NP concentrations; (d) force modulation AFM, as well as micro-Raman analysis, shows phase separation and aggregation of the gold nanoparticles within each dewetted polymer droplet leading to the formation of a metal core-polymer shell morphology. The polymer shell could be removed by washing in a selective solvent, thus exposing an array of bare gold nanoparticle aggregates.
International Nuclear Information System (INIS)
Murakami, Hiroyuki; Kawata, Shigeo; Niu, Keishiro.
1983-01-01
The stability of current-carrying plasma channels, which have been proposed for transporting intense ion beams from the diodes to the target in LIB-fusion devices, is discussed. The growth rate of the most dangerous surface mode, that is, the axisymmetric sausage instabilities, are examined for plasma channels with or without radial fluid motion. The growth rate of the channel with radial fluid motion is shown to be far smaller than that of the channel with no fluid motion. It is concluded that a stable plasma channel can be formed by radial fluid motion. (author)
Financial stability, monetary policy and budgetary coordination in EMU
Directory of Open Access Journals (Sweden)
Claudiu Tiberiu ALBULESCU
2012-08-01
Full Text Available A series of recent studies analyze the impact of financial crisis on the fiscal soundness in the Euro area countries. Even if their documented results present the transmission mechanisms of the financial instability toward the fiscal sector, a more realistic problem is related to the contribution of the fiscal and budgetary disequilibrium to the financial instability propagation. In this line, we show, based on a simple econometric model, that, beside the expansionary monetary policy, the budgetary deficit conducts to the financial stability deterioration. The financial stability of the Euro area is measured based on an aggregate financial stability index, constructed by employing the IMF methodology used for the financial stress index.
Social (in)stability, distributive conflicts, and investment in poor and rich economies
Riedl, A.M.
1999-01-01
A recently much debated issue is why observed investment and growth rates inpoor countries are lower than traditional theory predicts. Empirical evidencesuggests that social and political instability is a major reason for thedivergence between poor and rich countries. However, there is still the
Majidi, Carmel; O'Reilly, Oliver M.; Williams, John A.
2012-05-01
Using variational methods, we establish conditions for the nonlinear stability of adhesive states between an elastica and a rigid halfspace. The treatment produces coupled criteria for adhesion and buckling instabilities by exploiting classical techniques from Legendre and Jacobi. Three examples that arise in a broad range of engineered systems, from microelectronics to biologically inspired fiber array adhesion, are used to illuminate the stability criteria. The first example illustrates buckling instabilities in adhered rods, while the second shows the instability of a peeling process and the third illustrates the stability of a shear-induced adhesion. The latter examples can also be used to explain how microfiber array adhesives can be activated by shearing and deactivated by peeling. The nonlinear stability criteria developed in this paper are also compared to other treatments.
International Nuclear Information System (INIS)
Minami, Kazuo; Sato, Kazunori.
1978-09-01
The dynamic shear stabilization of the hydromagnetic instability in low-beta plasmas by an axial RF current whose frequency is not much smaller than the ion cyclotron frequency ωsub(ci) is analyzed in some detail. We adopt the simple model of a uniform plasma column with infinite conductivity. Attention is limited to the case of the m = 1 kink mode with long wave lengths. The Mathieu equation, in which the effect of the ion cyclotron motion is taken into account, is derived. It is shown that the dynamic shear stabilization is still effective, even if the frequency of the applied RF current is of the order of ωsub(ci), which is considerably higher than the frequencies believed to be available in the previous analyses. (author)
Bakshi, Neil K; Jameel, Omar F; Merrill, Zachary F; Debski, Richard E; Sekiya, Jon K
2016-08-01
This study compared the amount of glenohumeral abduction during arm abduction in the affected and unaffected shoulders of 3 groups of patients with shoulder instability: failed surgical stabilization, successful surgical stabilization, and unstable shoulder with no prior surgical intervention. All patients underwent bilateral shoulder computed tomography scans in 3 positions: 0° of abduction and 0° of external rotation (0-0 position), 30° of abduction and 30° of external rotation (30-30 position), and arms maximally abducted (overhead position). Three-dimensional computed tomography reconstruction was performed for both shoulders in all 3 positions. A specialized coordinate system marked specific points and directions on the humerus and glenoid of each model. These coordinates were used to calculate the glenohumeral abduction for the normal and affected sides in the 0-0, 30-30, and overhead positions. Thirty-nine patients with shoulder instability were included, of whom 14 had failed surgical repairs, 10 had successful surgical repairs, and 15 had unstable shoulders with no prior surgical intervention. In the overhead position, patients with failed surgical intervention had significantly less glenohumeral abduction in the failed shoulder (95.6° ± 12.7°) compared with the normal shoulder (101.5° ± 12.4°, P = .02). Patients with successfully stabilized shoulders had significantly less glenohumeral abduction in the successfully stabilized shoulder (93.6° ± 10.8°) compared with the normal shoulder (102.1° ± 12.5°, P = .03). Unstable shoulders with no prior surgical intervention (102.1° ± 10.3°) did not differ when compared with the normal shoulders (101.9° ± 10.9°, P = .95). Surgical intervention, regardless of its success, limits the amount of abduction at the glenohumeral joint. Level III, retrospective comparative study. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Tare, U.A.; Mody, F.K.; Mese, A.I. [Halliburton Energy Services, Cairo (Egypt)
2000-11-01
Experimental studies were conducted to explain the concept of a real-time wellbore (in)stability logging methodology. The role of the chemical potential of drilling fluids on transient pore pressure and time-dependent rock property alterations of shale formations was examined by providing details about a pore pressure transmission (PPT) test. The PPT experiments exposed formation (shale) cores under simulated downhole conditions to various salt solutions and drilling fluids. The main objective was to translate the results of the PPT tests to actual drilling conditions. A 20 per cent w/w calcium chloride solution was exposed to a Pierre II shale under high pressure in the PPT apparatus. The PPT test was used to estimate the impact of a drilling fluid on shale pore pressure. The efficiency of the salt solution/shale system was also estimated. Estimates of the dynamic rock properties were made based on the obtained acoustic data. It was determined that in order to accurately model time-dependent wellbore (in)stability in the field, it is important to calibrate representative shale core response to drilling fluids under realistic in-situ conditions. The 20 per cent w/w calcium chloride solution showed very low membrane efficiency of 4.45 per cent. It was concluded that changes in the shale dynamic rock properties as a function of test fluid exposure can be obtained from the simultaneous acquisition of sonic compression and shear wave velocity data. 12 refs., 5 figs.
Renormalization, averaging, conservation laws and AdS (in)stability
International Nuclear Information System (INIS)
Craps, Ben; Evnin, Oleg; Vanhoof, Joris
2015-01-01
We continue our analytic investigations of non-linear spherically symmetric perturbations around the anti-de Sitter background in gravity-scalar field systems, and focus on conservation laws restricting the (perturbatively) slow drift of energy between the different normal modes due to non-linearities. We discover two conservation laws in addition to the energy conservation previously discussed in relation to AdS instability. A similar set of three conservation laws was previously noted for a self-interacting scalar field in a non-dynamical AdS background, and we highlight the similarities of this system to the fully dynamical case of gravitational instability. The nature of these conservation laws is best understood through an appeal to averaging methods which allow one to derive an effective Lagrangian or Hamiltonian description of the slow energy transfer between the normal modes. The conservation laws in question then follow from explicit symmetries of this averaged effective theory.
On (in)stabilities of perturbations in mimetic models with higher derivatives
Energy Technology Data Exchange (ETDEWEB)
Zheng, Yunlong; Shen, Liuyuan [Department of Physics, Nanjing University, Nanjing 210093 (China); Mou, Yicen; Li, Mingzhe, E-mail: zylakx@163.com, E-mail: sly12271103@163.com, E-mail: moinch@mail.ustc.edu.cn, E-mail: limz@ustc.edu.cn [Interdisciplinary Center for Theoretical Study, University of Science and Technology of China, Hefei, Anhui 230026 (China)
2017-08-01
Usually when applying the mimetic model to the early universe, higher derivative terms are needed to promote the mimetic field to be dynamical. However such models suffer from the ghost and/or the gradient instabilities and simple extensions cannot cure this pathology. We point out in this paper that it is possible to overcome this difficulty by considering the direct couplings of the higher derivatives of the mimetic field to the curvature of the spacetime.
Simpson, Jeffrey D; Stewart, Ethan M; Macias, David M; Chander, Harish; Knight, Adam C
2018-06-13
To evaluate the literature regarding unilateral landing biomechanics and dynamic postural stability in individuals with and without chronic ankle instability (CAI). Four online databases (PubMed, ScienceDirect, Scopus, and SportDiscus) were searched from the earliest records to 31 January 2018, as well as reference sections of related journal articles, to complete the systematic search. Studies investigating the influence of CAI on unilateral landing biomechanics and dynamic postural stability were systematically reviewed and evaluated. Twenty articles met the criteria and were included in the systematic review. Individuals with CAI were found to have deficits in dynamic postural stability on the affected limb with medium to large effect sizes and altered lower extremity kinematics, most notably in the ankle and knee, with medium to large effect sizes. Additionally, greater loading rates and peak ground reaction forces, in addition to reductions in ankle muscle activity were also found in individuals with CAI during unilateral jump-landing tasks. Individuals with CAI demonstrate dynamic postural stability deficits, lower extremity kinematic alterations, and reduced neuromuscular control during unilateral jump-landings. These are likely factors that contribute recurrent lateral ankle sprain injuries during dynamic activity in individuals with CAI. Copyright © 2018 Elsevier Ltd. All rights reserved.
Monetary policy and financial (in)stability : An integrated micro-macro approach
De Graeve, F.; Kick, T.; Koetter, M.; DeGraeve, F.
Evidence on central banks' twin objective, monetary and financial stability, is scarce. We suggest an integrated micro macro approach with two core virtues. First, we measure financial stability directly at the bank level as the probability of distress. Second, we integrate a microeconomic hazard
Facility stabilization project, fiscal year 1998 Multi-Year Workplan (MYWP) for WBS 1.4
International Nuclear Information System (INIS)
Floberg, W.C.
1997-01-01
The primary Facility Stabilization mission is to provide minimum safe surveillance and maintenance of facilities and deactivate facilities on the Hanford Site, to reduce risks to workers, the public and environment, transition the facilities to a low cost, long term surveillance and maintenance state, and to provide safe and secure storage of special nuclear materials, nuclear materials, and nuclear fuel. Facility Stabilization will protect the health and safety of the public and workers, protect the environment and provide beneficial use of the facilities and other resources. Work will be in accordance with the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement), local, national, international and other agreements, and in compliance with all applicable Federal, state, and local laws. The stakeholders will be active participants in the decision processes including establishing priorities, and in developing a consistent set of rules, regulations, and laws. The work will be leveraged with a view of providing positive, lasting economic impact in the region. Effectiveness, efficiency, and discipline in all mission activities will enable Hanford Site to achieve its mission in a continuous and substantive manner. As the mission for Facility Stabilization has shifted from production to support of environmental restoration, each facility is making a transition to support the Site mission. The mission goals include the following: (1) Achieve deactivation of facilities for transfer to EM-40, using Plutonium Uranium Extraction (PUREX) plant deactivation as a model for future facility deactivation; (2) Manage nuclear materials in a safe and secure condition and where appropriate, in accordance with International Atomic Energy Agency (IAEA) safeguards rules; (3) Treat nuclear materials as necessary, and store onsite in long-term interim safe storage awaiting a final disposition decision by US Department of Energy; (4) Implement nuclear materials
Peled, Ofer; Bar-Kalifa, Eran; Rafaeli, Eshkol
2017-12-01
Avoidant personality disorder (APD) is among the most prevalent personality disorders, but has received relatively little empirical attention. This study aims to characterize the frequency, intensity, and fluctuation patterns seen in the modes (self-states) of APD clients over the course of schema therapy (ST), a psychotherapy approach developed especially for personality disorders. The newly-developed client mode rating scale (CMRS) was used to code every 5-min segment (n = 645) of 60 ST sessions. Each segment was coded by two independent raters, achieving adequate reliability. The avoidant/detached mode was present in 74% of therapy segments and was the most intense and unstable mode; the vulnerable child mode was present in 58% of segments and was the second most intense and unstable mode; the dysfunctional parent mode was present in 40% of segments, and was the third most intense and unstable mode; the over-compensator, compliant-surrenderer, and healthy adult modes were present in around 33% of segments, but the healthy adult mode was significantly more stable than all others. Although 645 segments were coded, they were drawn from only 15 APD clients with no control group. Further studies are needed to established specificity to APD. This study demonstrates the utility of the mode concept as a lexicon for capturing personality states and their instability. It highlights the use of in-session segment-by-segment ratings to assess client change within psychotherapy. Although DSM5 fails to address instability as a criterion for avoidant personality disorder, the APD clients in the current study were characterized by considerable mode instability. Copyright © 2017 Elsevier Ltd. All rights reserved.
Shigemori, Keisuke; Sakaiya, Tatsuhiko; Otani, Kazuto; Fujioka, Shinsuke; Nakai, Mitsuo; Azechi, Hiroshi; Shiraga, Hiroyuki; Tamari, Yohei; Okuno, Kazuki; Sunahara, Atsushi; Nagatomo, Hideo; Murakami, Masakatsu; Nishihara, Katsunobu; Izawa, Yasukazu
2004-09-01
Hydrodynamic instabilities are key issues of the physics of inertial confinement fusion (ICF) targets. Among the instabilities, Rayleigh-Taylor (RT) instability is the most important because it gives the largest growth factor in the ICF targets. Perturbations on the laser irradiated surface grow exponentially, but the growth rate is reduced by ablation flow. The growth rate γ is written as Takabe-Betti formula: γ = [kg/(1+kL)]1/2-βkm/pa, where k is wave number of the perturbation, g is acceleration, L is density scale-length, β is a coefficient, m is mass ablation rate per unit surface, and ρa is density at the ablation front. We experimentally measured all the parameters in the formula for polystyrene (CH) targets. Experiments were done on the HIPER laser facility at Institute of Laser Engineering, Osaka University. We found that the β value in the formula is ~ 1.7, which is in good agreements with the theoretical prediction, whereas the β for certain perturbation wavelengths are larger than the prediction. This disagreement between the experiment and the theory is mainly due to the deformation of the cutoff surface, which is created by non-uniform ablation flow from the ablation surface. We also found that high-Z doped plastic targets have multiablation structure, which can reduce the RT growth rate. When a low-Z target with high-Z dopant is irradiated by laser, radiation due to the high-Z dopant creates secondary ablation front deep inside the target. Since, the secondary ablation front is ablated by x-rays, the mass ablation rate is larger than the laser-irradiated ablation surface, that is, further reduction of the RT growth is expected. We measured the RT growth rate of Br-doped polystyrene targets. The experimental results indicate that of the CHBr targets show significantly small growth rate, which is very good news for the design of the ICF targets.
Stability and instability of axisymmetric droplets in thermocapillary-driven thin films
Nicolaou, Zachary G.
2018-03-01
The stability of compactly supported, axisymmetric droplet states is considered for driven thin viscous films evolving on two-dimensional surfaces. Stability is assessed using Lyapunov energy methods afforded by the Cahn-Hilliard variational form of the governing equation. For general driving forces, a criterion on the gradient of profiles at the boundary of their support (their contact slope) is shown to be a necessary condition for stability. Additional necessary and sufficient conditions for stability are established for a specific driving force corresponding to a thermocapillary-driven film. It is found that only droplets of sufficiently short height that satisfy the contact slope criterion are stable. This destabilization of droplets with increasing height is characterized as a saddle-node bifurcation between a branch of tall, unstable droplets and a branch of short, stable droplets.
Schulz-Drost, S; Grupp, S; Pachowsky, M; Oppel, P; Krinner, S; Mauerer, A; Hennig, F F; Langenbach, A
2017-04-01
Stabilizing techniques of flail chest injuries usually need wide approaches to the chest wall. Three main regions need to be considered when stabilizing the rib cage: median-anterior with dissection of pectoral muscle; lateral-axillary with dissection of musculi (mm) serratus, externus abdominis; posterior inter spinoscapular with division of mm rhomboidei, trapezius and latissimus dorsi. Severe morbidity due to these invasive approaches needs to be considered. This study discusses possibilities for minimized approaches to the shown regions. Fifteen patients were stabilized by locked plate osteosynthesis (MatrixRib ® ) between May 2012 and April 2014 and prospectively followed up. Flail chest injuries were managed through limited incisions to the anterior, the lateral, and the posterior parts of the chest wall or their combinations. Each approach was 4-10 cm using Alexis ® retractor. One minimized approach offered sufficient access at least to four ribs posterior and laterally, four pairs of ribs anterior in all cases. There was no need to divide latissimus dorsi muscle. Trapezius und rhomboid muscles were only limited divided, whereas a subcutaneous dissection of serratus and abdominis muscles was necessary. A follow-up showed sufficient consolidation. pneumothorax (2) and seroma (2). Minimized approaches allow sufficient stabilization of severe dislocated rib fractures without extensive dissection or division of the important muscles. Keeping the arm and, thus, the scapula mobile is very important for providing the largest reachable surface of the rib cage through each approach.
The Congo Trap: MONUSCO Islands of Stability in the Sea of Instability
Directory of Open Access Journals (Sweden)
Alberto Barrera
2015-11-01
Full Text Available 2014 was a hopeful year for the Democratic Republic of Congo (DRC. The M23 movement had been defeated in military operations in which one of the last peacekeeping experiments, the UN Force Intervention Brigade, had played a decisive role. A third UN stabilization plan, the ‘islands of stability’ was proposed to continue the stabilization of a country considered in a post-conflict phase. However, the number of internally displaced persons (IDPs has almost tripled in the country since 2007. This article will argue that DRC is still immersed into an old social conflict that existed before the Congo Wars and the roots of which are not being addressed. It will argue that the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (MONUSCO and the ‘islands of stability’ strategy can address some of the secondary causes of the Congo conflict, such as its internationalization, the presence in DRC of foreign armed groups or the ‘blood minerals’, but cannot address its primary causes: land struggles, an old cycle of violence and the fragmentation of the Congolese society and political elite that is jeopardizing the restoration of the state authority. The huge dimensions of each of these factors make the Congo conflict ‘one of the most complex and intricate environments ever faced by a peacekeeping mission’, for which MONUSCO’s mandate, resources and stabilization strategy do not seem powerful enough. When the UN organized the 2006 elections legitimized a ‘spoiler state’, the bottleneck of all the reforms needed to stabilize the country. The UN fell thus into a trap and became part of the conflict. Lessons learned should be taken for future UN operations.
International Nuclear Information System (INIS)
Bud'ko, A.B.; Liberman, M.A.; Bondarenko, E.A.
1992-01-01
Since development of the RT modes in the ablatively accelerated plasma of laser targets imposes crucial limitations on symmetry of spherical implosions and hence on energy cumulation, it has been the subject of intensive numerical and analytical analysis in the recent years, particularly in the context of inertial confinement fusion. Recent thin-foil ablative-acceleration experiments as well as the results of 2D numerical simulations demonstrated substantial reduction of the instability growth rates compared with the classical theory predictions up to the total stabilization in the short-wavelength limit. The numerical results indicated that the main stabilization mechanism is convection. To derive the scaling laws for the RT growth rates and cut-off wavenumbers in the wide range of flow parameters, analytical solutions attract special interest. The analytical approach based on the discontinuity model was developed to analyze the reduction of the RT growth rates by the plasma convective flow and the thermal conductivity effects. The following major problem arises in the discontinuity approximation, which leaves the solution undetermined: the number of the boundary conditions on the perturbed ablation surface is not sufficient to derive the dispersion equation. One needs additional boundary conditions not associated with the conservation laws on the discontinuity surface to close the system of linearized equations for small perturbations. The stabilization effect of highly structured hydrodynamic profiles was studied by Mikaelian and Munro for a stationary plasma. Nevertheless, no reasonable analytical model was constructed taking into account the combined convective, thermal conductivity and density gradient reduction of the RT growth rates. In this report we develop the analytical approach based on the WKB approximation to analyze the stabilization of the RT modes in plasma with smooth density and velocity gradients. (author) 9 refs., 1 fig
Feedback stabilization of the axisymmetric instability of a deformable tokamak plasma
International Nuclear Information System (INIS)
Pomphrey, N.; Jardin, S.C.; Ward, D.J.
1989-01-01
The paper presents an analysis of the magnetohydrodynamic stability of the axisymmetric system consisting of a free boundary tokamak plasma with non-circular cross-section, finite resistivity passive conductors, and an active feedback system with magnetic flux pickup loops, a proportional amplifier with gain G and current carrying poloidal field coils. A numerical simulation of the system when G is set to zero identifies flux loop locations which correctly sense the plasma motion. However, when certain of these locations are incorporated into an active feedback scheme, the plasma fails to be stabilized, no matter what value of the gain is chosen. Analysis on the basis of an extended energy principle indicates that this failure is due to the deformability of the plasma cross-section. (author). 14 refs, 7 figs
Hankin, Elyshia J; Jerram, Richard M; Walker, Alexander M; King, Michael D; Warman, Christopher G A
2012-07-01
To describe outcome after transarticular facet screw stabilization and dorsal laminectomy for treatment of dynamic degenerative lumbosacral stenosis (DLS) in 26 dogs. Retrospective case series. Dogs (n = 26) with dynamic DLS. Medical records (2004-2009) of dogs treated with transarticular facet screw stabilization and dorsal laminectomy were reviewed. Dogs (n = 26) were available for immediate postoperative follow-up, 21 dogs at 6 weeks, and 15 at greater than 6 months. Dogs were evaluated by radiographic assessment and owner questionnaire. Lumbosacral (LS) intervertebral disc (IVD) spaces were measured on pre and postoperative 6-week and 6-month radiographs. In 23 dogs, improvement in clinical signs occurred within 7 days of surgery. Overall postsurgical complication rate directly related to the surgical procedure was 15.4%. LS IVD space measurements taken immediately postoperatively, at 6 weeks, and ≥ 6 months were all significantly increased compared with preoperative measurements. All working dogs (4) returned to full work within 14 months. Most owners (85%) reported their dog was ambulating normally at 6 months with no perceptible lameness during normal activity. All owners perceived their dog's ability to walk, run, and jump after surgery to be improved. Transarticular facet screw stabilization and dorsal laminectomy maintains distraction of the LS IVD space for medium-to-large breed dogs with dynamic DLS with a high degree of owner satisfaction, and is comparable to other reported surgical techniques for DLS. © Copyright 2012 by The American College of Veterinary Surgeons.
Shanbhogue, S.J.
2016-01-01
© 2015 The Combustion Institute. In this paper, we report results from an experimental investigation on transitions in the average flame shape (or microstructure) under acoustically coupled and uncoupled conditions in a 50 kW swirl stabilized combustor. The combustor burns CH4/H2 mixtures at atmospheric pressure and temperature for a fixed Reynolds number of 20,000 and fixed swirl angle. For both cases, essentially four different flame shapes are observed, with the transition between flame shapes occurring at the same equivalence ratio (for the same fuel mixture) irrespective of whether the combustor is acoustically coupled or uncoupled. The transition equivalence ratio depends on the fuel mixture. For the baseline case of pure methane, the combustor is stable close to the blowoff limit and the average flame in this case is stabilized inside the inner recirculation zone. As the equivalence ratio is raised, the combustor transitions to periodic oscillations at a critical equivalence ratio of φ=0.65. If hydrogen is added to the mixture, the same transition occurs at lower equivalence ratios. For all cases that we investigated, flame shapes captured using chemiluminescence imaging show that the transition to harmonic oscillations in the acoustically coupled cases is preceded by the appearance of the flame in the outer recirculation zone. We examine the mechanism associated with the transition of the flame between different shapes and, ultimately, the propagation of the flame into the outer recirculation zone as the equivalence ratio is raised. Using the extinction strain rates for each mixture at different equivalence ratios, we show that these transitions in the flame shape and in the instability (in the coupled case) for different fuel mixtures collapse as a function of a normalized strain rate : κextDU∞. We show that the results as consistent with a mechanism in which the flame must overcome higher strains prevailing in the outer recirculation zone, in order
Taamallah, Soufien; LaBry, Zachary A.; Shanbhogue, Santosh J.; Habib, Mohamed A. M.; Ghoniem, Ahmed F.
2014-01-01
Copyright © 2015 by ASME. In this paper, we conduct an experimental investigation to study the link between the flame macroscale structure - or flame brush spatial distribution - and thermo-acoustic instabilities, in a premixed swirl-stabilized dump combustor. We operate the combustor with premixed methane-air in the range of equivalence ratio (Φ) from the lean blowout limit to Φ = 0. 75. First, we observe the different dynamic modes in this lean range as Φ is raised. We also document the effect of Φ on the flame macrostructure. Next, we examine the correspondence between dynamic mode transitions and changes in flame macrostructure. To do so, we modify the combustor length - by downstream truncation - without changing the underlying flow upstream. Thus, the resonant frequencies of the geometry are altered allowing for decoupling the heat release rate fluctuations and the acoustic feedback. Mean flame configurations in the modified combustor and for the same range of equivalence ratio are examined, following the same experimental protocol. It is found that not only the same sequence of flame macrostructures is observed in both combustors but also that the transitions occur at a similar set of equivalence ratio. In particular, the appearance of the flame in the outside recirculation zone (ORZ) in the long combustor - which occurs simultaneously with the onset of instability at the fundamental frequency - happens at similar Φ when compared to the short combustor, but without being in latter case accompanied by a transition to thermo-acoustic instability. Then, we interrogate the flow field by analyzing the streamlines, mean, and rms velocities for the nonreacting flow and the different flame types. Finally, we focus on the transition of the flame to the ORZ in the acoustically decoupled case. Our analysis of this transition shows that it occurs gradually with an intermittent appearance of a flame in the ORZ and an increasing probability with Φ. The spectral
Taamallah, Soufien
2014-12-23
Copyright © 2015 by ASME. In this paper, we conduct an experimental investigation to study the link between the flame macroscale structure - or flame brush spatial distribution - and thermo-acoustic instabilities, in a premixed swirl-stabilized dump combustor. We operate the combustor with premixed methane-air in the range of equivalence ratio (Φ) from the lean blowout limit to Φ = 0. 75. First, we observe the different dynamic modes in this lean range as Φ is raised. We also document the effect of Φ on the flame macrostructure. Next, we examine the correspondence between dynamic mode transitions and changes in flame macrostructure. To do so, we modify the combustor length - by downstream truncation - without changing the underlying flow upstream. Thus, the resonant frequencies of the geometry are altered allowing for decoupling the heat release rate fluctuations and the acoustic feedback. Mean flame configurations in the modified combustor and for the same range of equivalence ratio are examined, following the same experimental protocol. It is found that not only the same sequence of flame macrostructures is observed in both combustors but also that the transitions occur at a similar set of equivalence ratio. In particular, the appearance of the flame in the outside recirculation zone (ORZ) in the long combustor - which occurs simultaneously with the onset of instability at the fundamental frequency - happens at similar Φ when compared to the short combustor, but without being in latter case accompanied by a transition to thermo-acoustic instability. Then, we interrogate the flow field by analyzing the streamlines, mean, and rms velocities for the nonreacting flow and the different flame types. Finally, we focus on the transition of the flame to the ORZ in the acoustically decoupled case. Our analysis of this transition shows that it occurs gradually with an intermittent appearance of a flame in the ORZ and an increasing probability with Φ. The spectral
Feedback stabilization of the axisymmetric instability of a deformable tokamak plasma
International Nuclear Information System (INIS)
Pomphrey, N.; Jardin, S.C.
1987-09-01
We analyze the magnetohydrodynamic (MHD) stability of the axisymmetric system consisting of a free boundary, non-circular cross-section tokamak plasma, finite resistivity passive conductors, and an active feedback system with magnetic flux pickup loops, a proportional amplifier with gain G, and current carrying poloidal field coils. Numerical simulation of a system that is unstable with G = 0 shows that for some placements of the pickup loops, the system will remain unstable for all values of G, while for other placements of the loops, the system will be stable for G > G/sub crit/. This behavior is explained by analysis using an extended energy principle, and it is shown to result from the deformability of the plasma cross section. 9 refs., 5 figs
DEFF Research Database (Denmark)
Feng, Xingyuan; Ljungwall, Christer; Guo, Sujian
2013-01-01
China's central–local relations have been marked by perpetual changes amidst economic restructuring. Fiscal decentralization on the expenditure side has been paralleled by centralization on the revenue side, accompanied by political centralization. Hence, our understanding of China's fiscal...... relations is not without controversy. This paper aims to make a theoretical contribution to the ongoing debate on ‘fiscal federalism’ by addressing crucial questions regarding China's central–local fiscal relations: first, to what extent do Chinese central–local fiscal relations conform to fiscal federalism...
Anisotropic gravitational instability
International Nuclear Information System (INIS)
Polyachenko, V.L.; Fridman, A.M.
1988-01-01
Exact solutions of stability problems are obtained for two anisotropic gravitational systems of different geometries - a layer of finite thickness at rest and a rotating cylinder of finite radius. It is shown that the anisotropic gravitational instability which develops in both cases is of Jeans type. However, in contrast to the classical aperiodic Jeans instability, this instability is oscillatory. The physics of the anisotropic gravitational instability is investigated. It is shown that in a gravitating layer this instability is due, in particular, to excitation of previously unknown interchange-Jeans modes. In the cylinder, the oscillatory Jeans instability is associated with excitation of a rotational branch, this also being responsible for the beam gravitational instability. This is the reason why this instability and the anisotropic gravitational instability have so much in common
Aikawa, Takeshi; Kanazono, Shinichi; Yoshigae, Yuki; Sharp, Nicholas J H; Muñana, Karen R
2007-07-01
To describe diagnostic findings, surgical technique, and outcome in dogs with thoracic spinal canal stenosis and vertebral instability secondary to congenital vertebral anomalies. Retrospective clinical study. Dogs (n=9) with thoracic spinal canal stenosis. Medical records (1995-1996; 2000-2006) of 9 dogs with a myelographic diagnosis of spinal canal stenosis and/or vertebral instability secondary to congenital vertebral anomaly that were surgically managed by vertebral stabilization with or without laminectomy were reviewed. Data on pre- and postoperative neurologic status, diagnostic findings, surgical techniques, and outcomes were retrieved. Follow-up evaluations were performed at 1, 2, and 6 months. Long-term outcome was assessed by means of clinical examination or owner telephone interviews. Spinal cord compression was confirmed by myelography, and in 2 dogs, dynamic compression by stress myelography. Eight dogs regained the ability to ambulate postoperatively. One dog with a partial recovery regained voluntary movement but did not become ambulatory. Spinal cord injury secondary to congenital vertebral anomaly may have a good outcome when treated by vertebral stabilization with or without laminectomy. Adequate stabilization of the vertebrae and improved neurologic outcome were achieved in most dogs. Vertebral stabilization using positively threaded profile pins and polymethylmethacrylate with or without laminectomy is an effective treatment for spinal canal stenosis and vertebral instability secondary to congenital thoracic vertebral anomalies.
The (in)stability of money demand in the Euro Area: Lessons from a cross-country analysis
Nautz, Dieter; Rondorf, Ulrike
2010-01-01
The instability of standard money demand functions has undermined the role of monetary aggregates for monetary policy analysis in the euro area. This paper uses country-specific monetary aggregates to shed more light on the economics behind the instability of euro area money demand. Our results obtained from panel estimation indicate that the observed instability of standard money demand functions could be explained by omitted variables like e.g. technological progress that are important for ...
Van de Moortel, Maxime
2018-05-01
We show non-linear stability and instability results in spherical symmetry for the interior of a charged black hole—approaching a sub-extremal Reissner-Nordström background fast enough—in presence of a massive and charged scalar field, motivated by the strong cosmic censorship conjecture in that setting: 1. Stability We prove that spherically symmetric characteristic initial data to the Einstein-Maxwell-Klein-Gordon equations approaching a Reissner-Nordström background with a sufficiently decaying polynomial decay rate on the event horizon gives rise to a space-time possessing a Cauchy horizon in a neighbourhood of time-like infinity. Moreover, if the decay is even stronger, we prove that the space-time metric admits a continuous extension to the Cauchy horizon. This generalizes the celebrated stability result of Dafermos for Einstein-Maxwell-real-scalar-field in spherical symmetry. 2. Instability We prove that for the class of space-times considered in the stability part, whose scalar field in addition obeys a polynomial averaged- L 2 (consistent) lower bound on the event horizon, the scalar field obeys an integrated lower bound transversally to the Cauchy horizon. As a consequence we prove that the non-degenerate energy is infinite on any null surface crossing the Cauchy horizon and the curvature of a geodesic vector field blows up at the Cauchy horizon near time-like infinity. This generalizes an instability result due to Luk and Oh for Einstein-Maxwell-real-scalar-field in spherical symmetry. This instability of the black hole interior can also be viewed as a step towards the resolution of the C 2 strong cosmic censorship conjecture for one-ended asymptotically flat initial data.
International Nuclear Information System (INIS)
McGuire, K.M.; Kugel, H.W.; La Haye, R.J.; Mauel, M.E.; Nevins, W.M.; Prager, S.C.
1997-01-01
The transient operating performance of magnetic confinement devices is often limited by one or two unstable MHD modes. The feedback stabilization of MHD instabilities is an area of research that is critical for improving the steady state performance and economic attractiveness of magnetic confinement devices. This growing realization motivated a Workshop dedicated to feedback stabilization of MHD instabilities, which was held from 11 to 13 December 1996 at Princeton Plasma Physics Laboratory. The resulting presentations, conclusions and recommendations are summarized. (author)
Joint Instability and Osteoarthritis
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Darryl Blalock
2015-01-01
Full Text Available Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA. Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.
Joint instability and osteoarthritis.
Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi
2015-01-01
Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA.
Terrorist Networks, Money Laundering Schemes, and Nation Stability
2010-06-01
Stabilization Initiative $106,400,000.00 to recon/stab Seven countries per fiscal year American Academy of Actuaries insured losses (relatively...Indicators Political Instability Task Force Report Mathematical Model (Linear Program Optimization) Develop a value system (utility theory) to...deeper ahead. 47 LIST OF REFERENCES American Academy of Actuaries (Finance Data). Retrieved September 20, 2009, from, http://www.actuary.org
Kleinnijenhuis, J.; Walter, A.S.
2014-01-01
Associative issue ownership refers to one of the prerequisites for representative democracy-public awareness of the issue priorities of competing political parties. This article addresses the question of how the instability of associative issue ownership at the micro level of individual voters,
Shanbhogue, S.J.; Sanusi, Y.S.; Taamallah, S.; Habib, M.A.; Mokheimer, E.M.A.; Ghoniem, A.F.
2016-01-01
© 2015 The Combustion Institute. In this paper, we report results from an experimental investigation on transitions in the average flame shape (or microstructure) under acoustically coupled and uncoupled conditions in a 50 kW swirl stabilized
Riva, F; Bisi, M C; Stagni, R
2013-01-01
Falls represent a heavy economic and clinical burden on society. The identification of individual chronic characteristics associated with falling is of fundamental importance for the clinicians; in particular, the stability of daily motor tasks is one of the main factors that the clinicians look for during assessment procedures. Various methods for the assessment of stability in human movement are present in literature, and methods coming from stability analysis of nonlinear dynamic systems applied to biomechanics recently showed promise. One of these techniques is orbital stability analysis via Floquet multipliers. This method allows to measure orbital stability of periodic nonlinear dynamic systems and it seems a promising approach for the definition of a reliable motor stability index, taking into account for the whole task cycle dynamics. Despite the premises, its use in the assessment of fall risk has been deemed controversial. The aim of this systematic review was therefore to provide a critical evaluation of the literature on the topic of applications of orbital stability analysis in biomechanics, with particular focus to methodologic aspects. Four electronic databases have been searched for articles relative to the topic; 23 articles were selected for review. Quality of the studies present in literature has been assessed with a customised quality assessment tool. Overall quality of the literature in the field was found to be high. The most critical aspect was found to be the lack of uniformity in the implementation of the analysis to biomechanical time series, particularly in the choice of state space and number of cycles to include in the analysis. Copyright © 2012 Elsevier B.V. All rights reserved.
Streaming gravity mode instability
International Nuclear Information System (INIS)
Wang Shui.
1989-05-01
In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs
Japan's Fiscal Policy and Fiscal Reconstruction
Ihori, Toshihiro; Nakamoto, Atsushi
2005-01-01
This paper investigates the macroeconomic effects of fiscal policy and the fiscal reconstruction movement in Japan. We first summarize Japan's fiscal policy in recent years and discuss advantages and disadvantages of government deficits. Next, we investigate the macroeconomic effects of Japanese fiscal policy and evaluate the plausibility of non-Keynesian effects. We also analyze the possibility of the crowding-in effect of fiscal policy and investigate the spillover effects of deregulation. ...
New fiscal crisis Nueva crisis fiscal
Directory of Open Access Journals (Sweden)
Giraldo Giraldo César
1996-06-01
Full Text Available The fiscal deficit in Latin America is currently caused by the external and internal debt, and the fact that economic authorities have lost the ability to manage an important part of macroeconomic policy as a result of the process of decentralization. Along with less macroeconomic control, destabilizing factors increase due to the greater mobility of international financial markets, where any changein signals provokes abrupt and massive movements of capital in favor of or against a country. This problem is aggravated by the dismantling of the principal regulations, especially those relating to exchange controls, foreign investment, and international trade. Fiscal policyends up defending the stability of the main economic variables, in anuncertain and unpredictable context determined by an autonomous finance capital. It defends the stability of three key prices: inflation, currency, and interest rateo An abrupt change in any of these may depreciate the real value of financial assets, with which financial wealth would disappear like foam.El déficit fiscal en América Latina se origina actualmente en las deuda externa e interna, y en que la autoridad económica ha perdido el manejo de una parte importante de la política macroeconómica como resultado del proceso de descentralización. A la par del menor control macroeconómico, los factores desestabilizadores aumentan por la mayor movilidad de mercados financieros internacionales, donde cualquier cambio en las señales suscita movimientos de capital abruptos y masivos en favor o en contra de un país. Este problema se agrava con el desmonte de las principales regulaciones, en especial a las referidas al control cambiario, la inversión extrnajera y el comercio internacional. La política fiscal termina defendiendo la estabilidad de las principales variables macroeconómicas, en un contexto incierto e impredecible determinado por un capital financiero autónomo. Defiende la estabilidad de tres
Asphahani, Aziz; Siegel, Sidney; Siegel, Edward
2010-03-01
Siegel [[J.Mag.Mag.Mtls.7,312(78); PSS(a)11,45(72); Semis.& Insuls.5(79)] (at: ORNL, ANS, Westin``KL"ouse, PSEG, IAEA, ABB) warning of old/new nuclear-reactors/spent-fuel-casks/refineries/ jet/missile/rocket-engines austenitic/FCC Ni/Fe-based (so MIS- called)``super"alloys(182/82;Hastelloy-X; 600;304/304L-SSs; 690 !!!) GENERIC ENDEMIC EXTANT detrimental(synonyms): Wigner's- diseas(WD)[J.Appl.Phys.17,857(46)]; Ostwald-ripening; spinodal- decomposition; overageing-embrittlement; thermomechanical- INstability: Mayo[Google: ``If Leaks Could Kill"; at flickr.com search on ``Giant-Magnotoresistance"; find: [SiegelPolitics(79)]; Hoffman[animatedsoftware.com],...what DOE/NRC MISlabels as ``butt-welds" ``stress-corrosion cracking" endpoint's ROOT-CAUSE ULTIMATE-ORIGIN is WD overageing-embrit- tlement caused brittle-fracture cracking from early/ongoing AEC/DOE-n``u''tional-la``v''atories sabotage!!!
EURO AREA FISCAL STRUCTURES. A MULTIVARIATE ANALYSIS
Directory of Open Access Journals (Sweden)
HURDUZEU Gheorghe
2014-07-01
Full Text Available The European framework for fiscal policies is constructed mainly on the objective of monitoring budget balances and public debt, allowing national governments to decide on the specific fiscal policy that is more suitable to their internal context and public needs. However, for Euro Area member states this autonomy is restricted by the conditions imposed through the Stability and Growth Pact. As the recent macroeconomic dynamics underlined the necesity of improving the fiscal outcomes, the fiscal framework was updated and modified by the provisions of the new European economic governance meant to avoid unsound and unsustainable fiscal policies that could affect the stability of other Euro Area member states. The Six-Pack, the Fiscal Compact and the other conditions imposed by the reform of the fiscal governance framework are meant to ensure more discipline in drafting and executing national budgets. Even so, national authorities maintain their fiscal sovereignty and the decision regarding fiscal structures remains at their disposal, as long as the drafts are approved and the outcomes are maintained in the limits imposed through the supranational fiscal framework. Regardless of the numerous differences between member states, similar trends regarding tax mixes can be noticed in time. The objectives of this paper is to analyze fiscal structures of Euro Area member states and to determine, if any, groups with similar fiscal structures, their composition and the similarities that characterize Euro Area in this respect. In order to have a clear overview of fiscal structures within Euro Area, we analyzed data for 17 member states, for year 2012, taking into consideration total general government revenue, indirect taxation, direct taxation and social contributions. As one of the aims of this paper is to determine whether in Euro Area the main contributors are corporations or individuals, we also analyzed the structure of direct taxation, dividing it into
Genomic instability following irradiation
International Nuclear Information System (INIS)
Hacker-Klom, U.B.; Goehde, W.
2001-01-01
Ionising irradiation may induce genomic instability. The broad spectrum of stress reactions in eukaryontic cells to irradiation complicates the discovery of cellular targets and pathways inducing genomic instability. Irradiation may initiate genomic instability by deletion of genes controlling stability, by induction of genes stimulating instability and/or by activating endogeneous cellular viruses. Alternatively or additionally it is discussed that the initiation of genomic instability may be a consequence of radiation or other agents independently of DNA damage implying non nuclear targets, e.g. signal cascades. As a further mechanism possibly involved our own results may suggest radiation-induced changes in chromatin structure. Once initiated the process of genomic instability probably is perpetuated by endogeneous processes necessary for proliferation. Genomic instability may be a cause or a consequence of the neoplastic phenotype. As a conclusion from the data available up to now a new interpretation of low level radiation effects for radiation protection and in radiotherapy appears useful. The detection of the molecular mechanisms of genomic instability will be important in this context and may contribute to a better understanding of phenomenons occurring at low doses <10 cSv which are not well understood up to now. (orig.)
Are Independent Fiscal Institutions Really Independent?
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Slawomir Franek
2015-08-01
Full Text Available In the last decade the number of independent fiscal institutions (known also as fiscal councils has tripled. They play an important oversight role over fiscal policy-making in democratic societies, especially as they seek to restore public finance stability in the wake of the recent financial crisis. Although common functions of such institutions include a role in analysis of fiscal policy, forecasting, monitoring compliance with fiscal rules or costing of spending proposals, their roles, resources and structures vary considerably across countries. The aim of the article is to determine the degree of independence of such institutions based on the analysis of the independence index of independent fiscal institutions. The analysis of this index values may be useful to determine the relations between the degree of independence of fiscal councils and fiscal performance of particular countries. The data used to calculate the index values will be derived from European Commission and IMF, which collect sets of information about characteristics of activity of fiscal councils.
Some Stylized Facts on Non-Systematic Fiscal Policy in the Euro Area
Marcellino, Massimiliano
2002-01-01
We derive a set of stylized facts on the effects of non-systematic fiscal policy in the four largest countries of the Euro area, and discuss their implications for the fiscal policy coordination debate, for the effectiveness of fiscal shocks in stabilizing the economies, and for the interaction of fiscal and monetary policy. We find relevant differences across countries in the effects of non-systematic fiscal policy, and substantial uncertainty about the size of these effects, which casts dou...
Izadpanah, Kaywan; Winterer, Jan; Vicari, Marco; Jaeger, Martin; Maier, Dirk; Eisebraun, Leonie; Ute Will, Jutta; Kotter, Elmar; Langer, Mathias; Südkamp, Norbert P; Hennig, Jürgen; Weigel, Mathias
2013-06-01
To show the feasibility of a stress magnetic resonance imaging (MRI) as a new method for simultaneous evaluation of the morphology and the functional integrity of the acromioclavicular joint (ACJ) ligamentous stabilizers. MRI of four volunteers, 10 patients with acute, and six with chronic ACJ injuries was performed using a 0.25 T open MRI scanner. A 2D-proton-density and a 3D-gradient-echo sequence at rest and under 6.5 kg shoulder traction were performed. Comparative measurements of the coracoclavicular and the acromioclavicular distance were performed. Additionally, the conoid and trapezoid ligament lengths were measured with multiplanar reconstructions. MRI at rest correctly identified tears of the coracoclavicular and the acromioclavicular ligaments in eight patients suffering acute ACJ injuries. Stress application helped to distinguish between partial and complete coracoclavicular ligament tears in two cases. Insufficiency of the ACJ ligaments was present in all acute and chronic ACJ injuries. Stress application in chronic ACJ ligaments revealed isolated insufficiency of the conoid ligament in three cases and of the trapezoid ligament in one case. Combined insufficiency was present in two cases. Stress MRI facilitates simultaneous acquisition of morphologic and functional information of the ACJ stabilizers. In acute ACJ injuries it helps to distinguish between partial and complete ligament tears. In chronic ACJ injuries it provides functional information of the ligament regrinds. Copyright © 2012 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Manuel Alberto Restrepo-Medina
2010-03-01
Full Text Available Una de las características distintivas del sistema constitucional adoptado en 1991 es el desarrollo de mecanismos de control al ejercicio de la autoridad, uno de los cuales es el control fiscal, que bajo un tratamiento normativo diferente del vigente hasta entonces, se orienta a la preservación de los recursos públicos y a su aplicación a los fines esenciales del Estado. Dentro del nuevo esquema constitucional del control fiscal, su objeto de vigilancia lo constituye la gestión fiscal, cuyo ejercicio inadecuado, lesivo del erario, da lugar a la deducción de la consecuente responsabilidad patrimonial por parte de las contralorías. Ante la ausencia de desarrollo legal dada la precariedad de la regulación procesal contenida en la Ley 42 de 1993, la evolución conceptual al respecto fue asumida por las altas cortes hasta la expedición de la Ley 610 de 2000. Sin embargo, la demora en la expedición del estatuto legal que desarrollara integralmente el ejercicio de esta atribución de las contralorías, impide efectuar un juicio sobre las bondades o las fallas de la existencia y aplicación de esta institución jurídica de estirpe constitucional.
Ross, Scott E.; Linens, Shelley W.; Wright, Cynthia J.; Arnold, Brent L.
2013-01-01
Context: Stochastic resonance stimulation (SRS) administered at an optimal intensity could maximize the effects of treatment on balance. Objective: To determine if a customized optimal SRS intensity is better than a traditional SRS protocol (applying the same percentage sensory threshold intensity for all participants) for improving double- and single-legged balance in participants with or without functional ankle instability (FAI). Design: Case-control study with an embedded crossover design. Setting: Laboratory. Patients or Other Participants: Twelve healthy participants (6 men, 6 women; age = 22 ± 2 years, height = 170 ± 7 cm, mass = 64 ± 10 kg) and 12 participants (6 men, 6 women; age = 23 ± 3 years, height = 174 ± 8 cm, mass = 69 ± 10 kg) with FAI. Intervention(s): The SRS optimal intensity level was determined by finding the intensity from 4 experimental intensities at the percentage sensory threshold (25% [SRS25], 50% [SRS50], 75% [SRS75], 90% [SRS90]) that produced the greatest improvement in resultant center-of-pressure velocity (R-COPV) over a control condition (SRS0) during double-legged balance. We examined double- and single-legged balance tests, comparing optimal SRS (SRSopt1) and SRS0 using a battery of center-of-pressure measures in the frontal and sagittal planes. Main Outcome Measure(s): Anterior-posterior (A-P) and medial-lateral (M-L) center-of-pressure velocity (COPV) and center-of-pressure excursion (COPE), R-COPV, and 95th percentile center-of-pressure area ellipse (COPA-95). Results: Data were organized into bins that represented optimal (SRSopt1), second (SRSopt2), third (SRSopt3), and fourth (SRSopt4) improvement over SRS0. The SRSopt1 enhanced R-COPV (P ≤ .05) over SRS0 and other SRS conditions (SRS0 = 0.94 ± 0.32 cm/s, SRSopt1 = 0.80 ± 0.19 cm/s, SRSopt2 = 0.88 ± 0.24 cm/s, SRSopt3 = 0.94 ± 0.25 cm/s, SRSopt4 = 1.00 ± 0.28 cm/s). However, SRS did not improve R-COPV over SRS0 when data were categorized by sensory threshold
Relativistic gravitational instabilities
International Nuclear Information System (INIS)
Schutz, B.F.
1987-01-01
The purpose of these lectures is to review and explain what is known about the stability of relativistic stars and black holes, with particular emphases on two instabilities which are due entirely to relativistic effects. The first of these is the post-Newtonian pulsational instability discovered independently by Chandrasekhar (1964) and Fowler (1964). This effectively ruled out the then-popular supermassive star model for quasars, and it sets a limit to the central density of white dwarfs. The second instability was also discovered by Chandrasekhar (1970): the gravitational wave induced instability. This sets an upper bound on the rotation rate of neutron stars, which is near that of the millisecond pulsar PSR 1937+214, and which is beginning to constrain the equation of state of neutron matter. 111 references, 5 figures
International Nuclear Information System (INIS)
Lindl, J.D.; Mead, W.C.
1975-01-01
LASNEX calculations with a modified electron conductivity show the existence of a firepolishing stabilization effect. By modifying the thermal conductivity so that K α T/sup n//rho/sup m/, one is able to construct a situation in which the electrons deposit their energy in a thin layer at the ablation surface and closely match the zero order solutions assumed earlier. The firepolishing effect appears to require that a significant fraction of the total pressure be due to the ablation process itself rather than the thermal pressure in the corona gas. It also requires KL approximately 1 where L is the scale height for decay of thermal perturbations generated at the ablation surface. For classical electron conductivity, because the thermal flux depends linearly on the grams/cm 2 necessary to stop the electrons, (1/rho) nabla rho approximately (1/T) nabla T near the ablation surface so that the pressure is nearly constant across the ablation surface. Hence there is no ablation pressure as such and no firepolishing effect for electron-driven implosions
Directory of Open Access Journals (Sweden)
Piotr Lewitowicz
Full Text Available Colorectal cancer belongs to the most frequent occurring malignancies. A prediction of the clinical outcome and appropriate choice of neoadjuvant chemotherapy needs personalized insight to the main driving pathways. Because most CRCs have polyps as progenitor lesions, studying the pathways driving to adenomagenesis is no less important.Our purpose was the evaluation of microsatellite stability status within conventional colon adenomas and also β-catenin, BRAFV600E and p53 contribution.The cohort included 101 cases of typical colon adenomas with high grade epithelial dysplasia according to WHO. An immunohistochemistry method was used for the depiction of the expression of targeted proteins, as also their heterogeneity.Generally, we noted a 10% frequency of MSI events where MSI-H reached a 5% share occurred within the left colon and rectal polyps. β-catenin nuclear overexpression was noted with a 70% frequency and p53 with close to a 24% frequency. In addition, we found a presence of micro-serration foci more often within tubular adenomas, where focal MSI took place more often. Our results indicate that MSI events occur more often than had been theorized earlier. It results in tumour heterogeneity, more complex underlying pathways and finally ontogenetic molecular-diversity of tumours besides similar occurring histopathological features.
Fiscal Year 2013 Revegetation Assessment
Energy Technology Data Exchange (ETDEWEB)
Nordstrom, Jenifer [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2013-11-01
This report summarizes the Fiscal Year 2013 Revegetation Assessment by Battelle Energy Alliance, LLC. This assessment was conducted to supplement documentation related to the Storm Water Pollution Prevention Plan for Construction Activities and to ensure that disturbed vegetation and soil at various locations are being restored. This report provides the following information for each site being monitored by the Idaho National Laboratory Environmental Support and Services: Summary of each site Assessment of vegetation status and site stabilization at each location Actions and Resolutions for each site. Six disturbed sites were evaluated for this assessment. One has achieved final stabilization. The remaining five sites not meeting the criteria for final stabilization will be evaluated again in the next fiscal year.
Fiscal Year 2012 Revegetation Assessment
Energy Technology Data Exchange (ETDEWEB)
Jenifer Nordstrom
2012-11-01
This report summarizes the Fiscal Year 2012 Revegetation Assessment by Battelle Energy Alliance, LLC. This assessment was conducted to supplement documentation related to the Storm Water Pollution Prevention Plan for Construction Activities and to ensure that disturbed vegetation and soil at various locations are being restored. This report provides the following information for each site being monitored by the Idaho National Laboratory Environmental Support and Services: • Summary of each site • Assessment of vegetation status and site stabilization at each location • Actions and Resolutions for each site. Ten disturbed sites were evaluated for this assessment. Six have achieved final stabilization. The remaining four sites not meeting the criteria for final stabilization will be evaluated again in the next fiscal year.
Fiscal maneuver and restructuring of the Russian economy
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Alexey Kudrin
2017-09-01
Full Text Available The paper discusses fiscal policy parameters through 2024. The suggested way to ensure long-term fiscal stability is stabilizing both the general government revenues and expenditures as percentages of GDP at levels differing by the public debt service payments and then applying a new version of the fiscal rule. The redistribution of fiscal spending from unproductive to productive areas (primarily investment in human and physical capital is considered to boost economic growth. The possible use of additional spending on education, public health, and transport systems is presented, as is the optimization of expenditures in nonproductive areas.
Directory of Open Access Journals (Sweden)
Christian Kraus
2016-03-01
Full Text Available In the present work, combustion instabilities of a modular combustor are investigated. The combustor operates with partially premixed, swirl-stabilized flames and can be operated in single- and different multiple-burner setups. The design parameters of the combustor prevent large-scale flame–flame interactions in the multiple-burner arrangements. The objective is to investigate how the interaction of the swirl jets affects the thermoacoustic stability of the combustor. Results of measurements of pressure oscillations and high-speed OH*-chemiluminescence imaging for the single-burner setup and two multiple-burner setups are discussed. Additionally, results of investigations with different flame characteristics are presented. These are achieved by varying the ratio of the mass flow rates through the swirlers of the double-concentric swirl nozzle. Several unstable modes with high pressure amplitudes are observed in the single-burner setup as well as in the multiple-burner setups. Numerical studies of the acoustic behavior of the combustor setups were performed that indicate that the different geometries show similar acoustic behaviors. The results lead to the conclusion that the interaction of the swirl jets in the multiple-burner setups affects the thermoacoustic response spectrum of the flame even in the absence of large-scale flame–flame interactions. Based on the findings in earlier studies, it is concluded that the differences in the flame response characteristics are induced by the reduction of the swirl intensity in the multiple-burner arrangements, which is caused by the exchange of momentum between the adjacent swirl jets.
Fiscal policies in the European Union during the crisis
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Ferreiro Jesús
2015-01-01
Full Text Available The paper studies the fiscal policies implemented in the European Union countries since the beginning of the current crisis. With this aim in mind we have analyzed separately the expansionary fiscal policies implemented at the first stage of the crisis and the fiscal consolidation policies that became widespread at the beginning of the current decade. Studying the content of the national fiscal policies (discretionary measures versus built-in stabilizers, revenue-based versus expenditure-based fiscal policies, the relationship existing between the size of the fiscal impulses-adjustments and the composition of these measures shows the significant differences between the fiscal policies implemented in the European Union countries.
Fiscal Transparency and Procyclical Fiscal Policy
DEFF Research Database (Denmark)
Andersen, Asger Lau; Nielsen, Lasse Holbøll Westh
This paper examines why fiscal policy is procyclical in developing as well as developed countries. We introduce the concept of fiscal transparency into a model of retrospective voting, in which a political agency problem between voters and politicians generates a procyclical bias in government...... spending. The introduction of fiscal transparency generates two new predictions: 1) the procyclical bias in fiscal policy arises only in good times; and 2) a higher degree of fiscal transparency reduces the bias in good times. We find solid empirical support for both predictions using data on both OECD...
A general approach to optomechanical parametric instabilities
International Nuclear Information System (INIS)
Evans, M.; Barsotti, L.; Fritschel, P.
2010-01-01
We present a simple feedback description of parametric instabilities which can be applied to a variety of optical systems. Parametric instabilities are of particular interest to the field of gravitational-wave interferometry where high mechanical quality factors and a large amount of stored optical power have the potential for instability. In our use of Advanced LIGO as an example application, we find that parametric instabilities, if left unaddressed, present a potential threat to the stability of high-power operation.
International Nuclear Information System (INIS)
Wheeler, C.
1992-01-01
Most fiscal systems do not have provisions which adequately address the problems arising from the global nature of international oil and product trading. It is also difficult for the various tax authorities to keep abreast of the ever evolving hedging instruments. It is quite possible for an international trader or integrated oil company to find itself with losses which cannot match against profits either because of local tax rules or because the loss arises in one jurisdiction and profits in another. The corporate structuring and legal relationships of parties both within an organisation and outside can be key to mitigating effective double taxation and in assisting the production of reports to shareholders which show a fair picture of the group's activities. (author)
Taamallah, Soufien; LaBry, Zachary A.; Shanbhogue, Santosh J.; Ghoniem, Ahmed F.
2015-01-01
© 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved. We investigate the onset of thermo-acoustic instabilities and their link to the mean flame configurations - or macrostructures - under acoustically coupled
International Nuclear Information System (INIS)
Schmitt, R.; Froehner, S.; Coblenz, G.; Christopoulos, G.
2006-01-01
This review addresses the pathoanatomical basics as well as the clinical and radiological presentation of instability patterns of the wrist. Carpal instability mostly follows an injury; however, other diseases, like CPPD arthropathy, can be associated. Instability occurs either if the carpus is unable to sustain physiologic loads (''dyskinetics'') or suffers from abnormal motion of its bones during movement (''dyskinematics''). In the classification of carpal instability, dissociative subcategories (located within proximal carpal row) are differentiated from non-dissociative subcategories (present between the carpal rows) and combined patterns. It is essential to note that the unstable wrist initially does not cause relevant signs in standard radiograms, therefore being ''occult'' for the radiologic assessment. This paper emphasizes the high utility of kinematographic studies, contrast-enhanced magnetic resonance imaging (MRI) and MR arthrography for detecting these predynamic and dynamic instability stages. Later in the natural history of carpal instability, static malalignment of the wrist and osteoarthritis will develop, both being associated with significant morbidity and disability. To prevent individual and socio-economic implications, the handsurgeon or orthopedist, as well as the radiologist, is challenged for early and precise diagnosis. (orig.)
Plasma physics and instabilities
International Nuclear Information System (INIS)
Lashmore-Davies, C.N.
1981-01-01
These lectures procide an introduction to the theory of plasmas and their instabilities. Starting from the Bogoliubov, Born, Green, Kirkwood, and Yvon (BBGKY) hierarchy of kinetic equations, the additional concept of self-consistent fields leads to the fundamental Vlasov equation and hence to the warm two-fluid model and the one-fluid MHD, or cold, model. The properties of small-amplitude waves in magnetized (and unmagnetized) plasmas, and the instabilities to which they give rise, are described in some detail, and a complete chapter is devoted to Landau damping. The linear theory of plasma instabilities is illustrated by the current-driven electrostatic kind, with descriptions of the Penrose criterion and the energy principle of ideal MHD. There is a brief account of the application of feedback control. The non-linear theory is represented by three examples: quasi-linear velocity-space instabilities, three-wave instabilities, and the stability of an arbitrarily largeamplitude wave in a plasma. (orig.)
International Nuclear Information System (INIS)
Subhash, P V; Madhavan, S; Chaturvedi, S
2008-01-01
Two-dimensional (2D) magneto-hydrodynamic (MHD) liner-on-plasma computations have been performed to study the growth of instabilities in a magnetized target fusion system involving the cylindrical compression of an inverse Z-pinch target plasma by a metallic liner. The growth of modes in the plasma can be divided into two phases. During the first phase, the plasma continues to be Kadomtsev stable. The dominant mode in the liner instability is imposed upon the plasma in the form of a growing perturbation. This mode further transfers part of its energy to its harmonics. During the second phase, however, non-uniform implosion of the liner leads to axial variations in plasma quantities near the liner-plasma interface, such that certain regions of the plasma locally violate the Kadomtsev criteria. Further growth ofthe plasma modes is then due to plasma instability. The above numerical study has been complemented with a linear stability analysis for the plasma, the boundary conditions for this analysis being obtained from the liner-on-plasma simulation. The stability of axisymmetric modes in the first phase is found to satisfy the Kadomtsev condition Q 0 1 modes, using equilibrium profiles from the 2D MHD study, shows that their growth rates can exceed those for m=0 by as much as an order of magnitude
Expansionary fiscal contractions
DEFF Research Database (Denmark)
Bergman, Ulf Michael; Hutchison, Michael
2010-01-01
The Expansionary Fiscal Contraction (EFC) hypothesis predicts that a major fiscal consolidation leads to an economic expansion under certain circumstances. We test this hypothesis, and the implied non-linear responses of the economy to large and small changes in fiscal policy, using data from...... that the exogenous fiscal contraction in Denmark was a credible regime shift and, together with other reforms undertaken at the time, increased both private consumption and aggregate output....
Inadequate Revenue Threatens Afghanistan’s Stability
Directory of Open Access Journals (Sweden)
Steve Sternlieb
2014-04-01
Full Text Available If Afghanistan is to maintain some semblance of stability in 2014 and beyond it must prepare for a substantial donor funding reduction and seek to grow its domestic revenue. Funding for the Afghan government’s operating expenses as well as further development projects is heavily dependent on donor support. Unfortunately for Afghanistan, its fiscal position is eroding as domestic revenues decline, expenses rise, and donor aid falls. Security gains as well as public services and economic development are at risk due to this mismatch. Afghanistan’s challenge in the coming years will be how to deal with this mismatch without fueling instability. It cannot simply assume that donor funding will continue to cover its funding gap. This paper assesses Afghanistan’s deteriorating fiscal situation and concludes with some observations on what the Afghan government and the donor community must do, preferably in concert, to address it. It assumes that Afghanistan and the United States will ultimately sign a bilateral security agreement allowing a continued coalition military presence, without which the country’s fiscal situation could rapidly deteriorate.
Directory of Open Access Journals (Sweden)
Sanhita SUCHARITA
2011-07-01
Full Text Available The present study broadly attempts to analyze the role of Fiscal Responsibility and Budget Management Act in restoring fiscal balance in India. It analyses the need for fiscal rules and constraints in India. The study aims at finding out the major factor behind rising fiscal imbalance in India and to examine whether there is an electoral motive towards high fiscal deficit to GDP ratio or not. It also analyzes the effectiveness of various measures undertaken at the central and state level to inculcate fiscal discipline in the fiscal management. The study also makes an attempt to do a critical in depth reviews of the Fiscal Responsibility and Budget Management Act and make an attempt at examining effectiveness and suitability of FRBM Act through a quantitative analysis. It also makes an attempt to suggest improvements in the fiscal monitoring mechanism in India. We employ Ordinary Least Square (OLS method to examine the impact of Fiscal Responsibility and Budget Management Act on fiscal deficit in India using the data for the period 1980-81 to 2008-09. The regression results indicates that FRBM Act does not have a significant effect on the Gross Fiscal Deficit (GFD to GDP ratio where as GDP (at factor cost growth rate has a significant negative effect on the GFD to GDP ratio.
On the Logic of Separating the Fiscal Policy from the Fiscal Administration
Directory of Open Access Journals (Sweden)
Ionel Leonida
2010-06-01
Full Text Available One of the problems yet to be solved in a satisfactorily manner in Romania is the decentralisation of the public administration. In general, by decentralisation we understand the separation of the central decision from the local (or regional decision based on the principle of subsidiarity. In our opinion, The National Agency for Fiscal Administration should function, in a decentralised manner, meaning outside of the Ministry of Public Finances. In support of this statement we will present two modules or arguments: a wewill first debate on the matter of public administration decentralisation; b second, we will debate in favour ofthe institutional separation of ANAF from the Ministry of Public Finances. Objectives: Implementation of concrete desire for decentralization of public administration; Identification of conceptual distinctions, structural and functional development of tax policy and administration of fiscal policy. Prior work: Assessment of net tax burden; Phillips curve assessment for Romania; Automatic fiscal stabilizers; Sustainability of fiscal policy. Approach: Logical analysis of the concepts involved in the study; Highlighting the distinctions of semantic and pragmatic nature of the concepts involved in the study. Results: decisive arguments concerning the desirability of the structural separation of the fiscal policy from the fiscal administration. Implications: providing arguments for a separation of fiscal policy decision to tax administration; a collection efficiency of budgetary obligations. Potential beneficiaries : The Ministry of Finance; the National Agency for Fiscal Administration; the Government of Romania; the Ministry ofInternal Affairs and Administration. Value: Contributions from conceptual nature: semantic separation of fiscal policy from tax administration; from methodological nature: demonstrating scientific research force of un application logic analysis method; from empirical nature: demonstrating the need
Fiscal sustainability and fiscal policy targets
DEFF Research Database (Denmark)
Andersen, Torben M.
Analyses of fiscal sustainability have become integral parts of fiscal policy planning due to high debt levels and projected demographic changes. A popular metric by which to evaluate sustainability gaps is the so-called S2 metric given as the permanent change in the primary budget balance...... indicator can be given a normative interpretation, and this issue is extensively discussed. The paper ends by discussing the formulation of fiscal policy targets to ensure fiscal sustainability....... (relative to GDP) needed to meet the intertemporal budget constraint. While a very useful metric it also suffers from some problems, and the paper discusses some of the problems with this metric as a way to assess fiscal sustainability problems. A particular important issue is the extent to which the S2...
Directory of Open Access Journals (Sweden)
Muhammad H. Al-Malack
2016-07-01
Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.
Fiscal Capacity Equalisation in Tanzania
Allers, Maarten A.; Ishemoi, Lewis J.
2010-01-01
Fiscal equalisation aims at enabling decentralised governments to supply similar services at similar tax rates. In order to equalise fiscal disparities, differences in both fiscal capacities and in fiscal needs have to be measured. This paper focuses on the measurement of fiscal capacity in a
Hydrodynamick instabilities on ICF capsules
International Nuclear Information System (INIS)
Haan, S.W.
1991-01-01
This article summarizes our current understanding of hydrodynamic instabilities as relevant to ICF. First we discuss classical, single mode Rayleigh-Taylor instability, and nonlinear effects in the evolution of a single mode. Then we discuss multimode systems, considering: (1) the onset of nonlinearity; (2) a second order mode coupling theory for weakly nonlinear effects, and (3) the fully nonlinear regime. Two stabilization mechanisms relevant to ICF are described next: gradient scale length and convective stabilization. Then we describe a model which is meant to estimate the weakly nonlinear evolution of multi-mode systems as relevant to ICF, given the short-wavelength stabilization. Finally, we discuss the relevant code simulation capability, and experiments. At this time we are quite optimistic about our ability to estimate instability growth on ICF capsules, but further experiments and simulations are needed to verify the modeling. 52 refs
International Nuclear Information System (INIS)
Takeda, Tatsuoki
1985-01-01
In this article analyses of the MHD stabilities which govern the global behavior of a fusion plasma are described from the viewpoint of the numerical computation. First, we describe the high accuracy calculation of the MHD equilibrium and then the analysis of the linear MHD instability. The former is the basis of the stability analysis and the latter is closely related to the limiting beta value which is a very important theoretical issue of the tokamak research. To attain a stable tokamak plasma with good confinement property it is necessary to control or suppress disruptive instabilities. We, next, describe the nonlinear MHD instabilities which relate with the disruption phenomena. Lastly, we describe vectorization of the MHD codes. The above MHD codes for fusion plasma analyses are relatively simple though very time-consuming and parts of the codes which need a lot of CPU time concentrate on a small portion of the codes, moreover, the codes are usually used by the developers of the codes themselves, which make it comparatively easy to attain a high performance ratio on the vector processor. (author)
Takada, Motoshi; Taruishi, Chieko; Sudani, Tomoko; Suzuki, Akira; Iida, Hiroki
2013-08-01
Evaluation of the stabilizing effect of intravenous flurbiprofen axetil against hemodynamic instability due to mesenteric traction syndrome (MTS) by continuous measurement of systemic vascular resistance index (SVRI) using a FloTrac(®) sensor was evaluated. Prospective randomized trial. A single-center study performed in an educational hospital. Two prospective studies were carried out, each with 40 patients scheduled for elective open abdominal surgery. Twenty patients received 50 mg of flurbiprofen axetil after the recognition of MTS by the anesthesiologist (group FT). The remaining patients served as controls (groups CP and CT). SVRI data was collected every 20 seconds for 1 hour after starting the laparotomy. The average SVRI prior to skin incision was taken as the baseline. Following 3 values were devised to evaluate MTS: the S-value (sum total of changes in SVRI from baseline), the T-value (period during which SVRI remained 20% or more below baseline), and the M-value (maximum change in SVRI from baseline). In group FP, decrease in SVRI was smaller than in group CP, and statistical differences in the 3 values were found. In group FT, SVRI recovered earlier than in group CT, and statistical differences were found in S-value and T-value. However, the M-value had no statistical differences. Intravenous flurbiprofen axetil can stabilize the hemodynamic instability due to MTS. Copyright © 2013 Elsevier Inc. All rights reserved.
Linear waves and instabilities
International Nuclear Information System (INIS)
Bers, A.
1975-01-01
The electrodynamic equations for small-amplitude waves and their dispersion relation in a homogeneous plasma are outlined. For such waves, energy and momentum, and their flow and transformation, are described. Perturbation theory of waves is treated and applied to linear coupling of waves, and the resulting instabilities from such interactions between active and passive waves. Linear stability analysis in time and space is described where the time-asymptotic, time-space Green's function for an arbitrary dispersion relation is developed. The perturbation theory of waves is applied to nonlinear coupling, with particular emphasis on pump-driven interactions of waves. Details of the time--space evolution of instabilities due to coupling are given. (U.S.)
Thermal shrinkage for shoulder instability.
Toth, Alison P; Warren, Russell F; Petrigliano, Frank A; Doward, David A; Cordasco, Frank A; Altchek, David W; O'Brien, Stephen J
2011-07-01
Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent shoulder stabilization surgery with thermal capsular shrinkage using a monopolar radiofrequency device. Follow-up included a subjective outcome questionnaire, discussion of pain, instability, and activity level. Mean follow-up was 3.3 years (range 2.0-4.7 years). The thermal capsular shrinkage procedure failed due to instability and/or pain in 31% of shoulders at a mean time of 39 months. In patients with unidirectional anterior instability and those with concomitant labral repair, the procedure proved effective. Patients with multidirectional instability had moderate success. In contrast, four of five patients with isolated posterior instability failed. Thermal capsular shrinkage has been advocated for the treatment of shoulder instability, particularly mild to moderate capsular laxity. The ease of the procedure makes it attractive. However, our retrospective review revealed an overall failure rate of 31% in 80 patients with 2-year minimum follow-up. This mid- to long-term cohort study adds to the literature lacking support for thermal capsulorrhaphy in general, particularly posterior instability. The online version of this article (doi:10.1007/s11420-010-9187-7) contains supplementary material, which is available to authorized users.
The Credibility of Fiscal Rules Policy and Business Cycle Volatility
Directory of Open Access Journals (Sweden)
Kuncoro Haryo
2016-06-01
Full Text Available The aim of this paper is two-fold; first, it studies the impact of the credibility of fiscal rule policy on the stability of output growth; second, it compares the effectiveness of fiscal rule policy to discretionary and automatic stabilizer fiscal policies to address the fluctuation of output growth. Employing quarterly data over the period 2001-2013 in the case of Indonesia, we obtain that the credible debt rule leads to a decrease in the volatility of output growth while the non-credible deficit rule does not have any effect. Both unsystematic and systematic components of discretionary fiscal policy have a stabilizing function. Interestingly, the automatic stabilization tends to induce the volatility of output growth. Given those results, we infer that government spending is not a good automatic stabilizer. It seems that the lower ratio of government expenditure to GDP along with improving credibility of deficit rule policy has a smoother effect on the economy. Therefore, they implicitly support expenditure cuts when implementing fiscal adjustment with the purpose of reaching fiscal sustainability in the short-run and a stable economic growth in the long-run.
Directory of Open Access Journals (Sweden)
Petru GRICIUC
2015-12-01
Full Text Available Cadrul analitic pe care autorul îl dezvoltă în acest articol sugerează trei dimensiuni cu ajutorul cărora poate fi eva-luat impactul politicii fiscale asupra funcţionalităţii economiei naţionale. Aceste dimensiuni sunt: sustenabilitatea fis-cală; structura fiscală; stabilizarea fiscală. Eforturile pe care Republica Moldova trebuie să le depună pentru a asigura sustenabilitatea fiscală, o structură fiscală eficientă şi îmbunătăţi stabilitatea macroeconomică ţin de: cadrul fiscal (cadrul legislativ şi instituţional, politica fiscală şi managementul fiscal.FISCAL SYSTEM OPTIMIZATION – PREMISE FOR CREATING A FUNCTIONAL MARKET ECONOMY IN THE REPUBLIC OF MOLDOVAThe analytical framework that the author develops in this article suggests three dimensions by which it is possible to assess the impact of fiscal policy impact on the functionality of the national economy. The dimensions are the fiscal sustainability, the tax structure, and fiscal stabilization. The efforts that Moldova should make to ensure a fiscal sustainability, an efficient tax structure and improved macroeconomic stability are related to the fiscal framework (legislative and institutional, fiscal policy and fiscal management.
Kulić, Mirko; Milošević, Goran; Milašinović, Srđan
2011-01-01
There are various forms of attacks against the fiscal interests of the state, which, according to the current legislation, are gaining the character of criminal offences. In some states, there is a tendency of increase in number of fiscal criminal offences, which is the result of multiplication of illegal activities aiming at avoidance of payment of fiscal revenues. Changes in the development of state finances lead also to changes in the field of incriminations - over time some of them disapp...
Fiscal Year 2009 Revegetation Assessment
Energy Technology Data Exchange (ETDEWEB)
Michael Lewis
2009-10-01
This report summarizes the Fiscal Year 2009 Revegetation Assessment by Battelle Energy Alliance, LLC. This assessment was conducted to supplement documentation related to the Storm Water Pollution Prevention Plan for Construction Activities and to ensure that disturbed vegetation and soil at various locations are being restored. This report provides the following information for each site being monitored by the Idaho National Laboratory Environmental Support and Services: • Summary of each site • Assessment of vegetation status and site stabilization at each location • Recommendation(s) for each site.
Fiscal Year 2010 Revegetation Assessment
Energy Technology Data Exchange (ETDEWEB)
Jenifer Nordstrom; Mike Lewis
2010-11-01
This report summarizes the Fiscal Year 2010 Revegetation Assessment by Battelle Energy Alliance, LLC. This assessment was conducted to supplement documentation related to the Storm Water Pollution Prevention Plan for Construction Activities and to ensure that disturbed vegetation and soil at various locations are being restored. This report provides the following information for each site being monitored by the Idaho National Laboratory Environmental Support and Services: • Summary of each site • Assessment of vegetation status and site stabilization at each location • Recommendation(s) for each site.
Petroleum fiscality indicators
International Nuclear Information System (INIS)
2008-02-01
This document presents the different taxes imposed to petroleum products in France: domestic tax on petroleum products (TIPP) and added value tax (TVA). A comparison is made with the fiscality into effect in other European countries for some petroleum products. Then, the fiscality is detailed for the different petroleum products and automotive fuels with its regional modulations. Finally, the fiscal measures adopted in 2007 are detailed. They concern the transposition of the European directive 2003-96/CE into French right and some fiscal regime changes given to some economical sectors particularly penalized by the rise of petroleum energy prices in 2007. (J.S.)
WELLBORE INSTABILITY: CAUSES AND CONSEQUENCES
Directory of Open Access Journals (Sweden)
Borivoje Pašić
2007-12-01
Full Text Available Wellbore instability is one of the main problems that engineers meet during drilling. The causes of wellbore instability are often classified into either mechanical (for example, failure of the rock around the hole because of high stresses, low rock strength, or inappropriate drilling practice or chemical effects which arise from damaging interaction between the rock, generally shale, and the drilling fluid. Often, field instances of instability are a result of a combination of both chemical and mechanical. This problem might cause serious complication in well and in some case can lead to expensive operational problems. The increasing demand for wellbore stability analyses during the planning stage of a field arise from economic considerations and the increasing use of deviated, extended reach and horizontal wells. This paper presents causes, indicators and diagnosing of wellbore instability as well as the wellbore stresses model.
Fiscal policy lags and income adjustment processes
International Nuclear Information System (INIS)
De Cesare, Luigi; Sportelli, Mario
2012-01-01
Highlights: ► There are delays either in the government expenditure or in the tax system. ► Both delays affect fiscal policy outcomes. ► The system of differential equations with two delays may be chaotic. ► Fiscal policy outcomes might be inconsistent with their stabilization purposes. - Abstract: The interest in the impact of fiscal policy lags on economic stability increased in the last decade. Several studies have been made on delays either in the government expenditure or in the tax system, where lags exist between the accrual and the payment of taxes. Nevertheless there is in the literature no model where time delays in government expenditures and in tax revenues are considered together as it happens in the real world. In this paper we remedied this defect and proposed a macro-dynamic model where two delays appear: the first pertains to the public expenditure, the second, to the tax revenue. The resulting system of delayed differential equations is studied qualitatively and numerically. The analysis suggests that only particular combinations of the two delays make the system stable. Prevalently the system is unstable and chaotic motions may arise. This implies that the economy may need appropriate structural changes in the public sector to improve fiscal policy outcomes in such a way they may really be consistent with their stabilization purposes.
Borner, Tim; Ramisch, Sebastian; Reddem, Eswar R.; Bartsch, Sebastian; Vogel, Andreas; Thunnissen, Andy-Mark W. H.; Adlercreutz, Patrick; Grey, Carl
The insufficient operational stability of amine transaminases (ATA) constitutes a limiting factor for high productivity in chiral amine synthesis. In this work, we investigated the operational stability of a tetrameric ATA with 92% sequence identity to a Pseudomonas sp. transaminase and compared it
Krips, Rover; de Vries, Jasper; van Dijk, C. Niek
2006-01-01
The ankle joint is the most congruent joint of the human body. Stability is provided by the bony configuration of the ankle mortise and the talar dome and by the ankle ligaments. During ankle motions, rotation and translation around and along the movement axes occur. Soft tissue stability is
Pierce instability and bifurcating equilibria
International Nuclear Information System (INIS)
Godfrey, B.B.
1981-01-01
The report investigates the connection between equilibrium bifurcations and occurrence of the Pierce instability. Electrons flowing from one ground plane to a second through an ion background possess a countable infinity of static equilibria, of which only one is uniform and force-free. Degeneracy of the uniform and simplest non-uniform equilibria at a certain ground plan separation marks the onset of the Pierce instability, based on a newly derived dispersion relation appropriate to all the equilibria. For large ground plane separations the uniform equilibrium is unstable and the non-uniform equilibrium is stable, the reverse of their stability properties at small separations. Onset of the Pierce instability at the first bifurcation of equilibria persists in more complicated geometries, providing a general criterion for marginal stability. It seems probable that bifurcation analysis can be a useful tool in the overall study of stable beam generation in diodes and transport in finite cavities
On nonlinear development of beam instability
International Nuclear Information System (INIS)
Popel', S.I.; Tsytovich, V.N.
1990-01-01
Radiation-resonance interactions are taken into account in the problem of dynamics of an electron beam inb plasma. The beam characteristics to be taken into account are determined. Stabilization conditions for beam instability are established
Kendrick, D.A.; Amman, H.M.
2014-01-01
Monetary policy is altered once a month. Fiscal policy is altered once a year. As a potential improvement this article examines the use of feedback control rules for fiscal policy that is altered quarterly. Following the work of Blinder and Orszag, modifications are discussed in Congressional
van Oudheusden, P.
2013-01-01
This thesis deals with selected topics in fiscal policy. The first part examines the relationship between fiscal decentralization and certain outcomes, one being the amount of trust citizens have in their government, the other being economic efficiency. The second part looks into the challenge of
Gerbault-Seureau, Michèle; Cacheux, Lauriane; Dutrillaux, Bernard
2017-01-01
Amongst Cercopithecidae, the species of the Cercopithecini tribe underwent a very active chromosome evolution, principally by fissions, which increased their chromosome number up to 72. In contrast, all the species of Papionini have fairly similar karyotypes with 42 chromosomes. In animals, nucleolus organizer regions (NORs) are generally considered as instable structures, which frequently vary in size, number, and location at both infra- and interspecific levels. Although in Cercopithecinae the NORs, involved in breaks, exchanges, and translocations, behave like fragile sites in somatic cells, their number and location appear to be very stable between species. Fluorescence in situ hybridization of a 28S rDNA probe on metaphase chromosomes displayed a unique interstitial location in either an acrocentric pair (in 12 species of Cercopithecini) or a metacentric pair (in 6 species of Papionini). A non-exhaustive survey of literature data on NOR location in other primates shows that numerical variations of the NORs principally depend on their location: most multiple NORs are in terminal positions, while almost all unique NORs are in interstitial positions. We propose that this correlation is the consequence of the selection against gametic imbalances involving the chromosomal material distal to the NORs, which is effective when they are interstitially, but not terminally, located. Thus, the consequences of the interstitial NOR instability for reproduction are essentially limited to their size variations, as observed in Cercopithecidae. © 2018 S. Karger AG, Basel.
Tax incentives in fiscal federalism
DEFF Research Database (Denmark)
Kelders, Christian; Köthenbürger, Marko
2010-01-01
Models of fiscal federalism rarely account for the efficiency implications of intergovernmental fiscal ties for federal tax policy. This paper shows that fiscal institutions such that federal tax deductibility, vertical revenue-sharing, and fiscal equalization (being common features of existing...
Electromagnetic theory of the radiative Pierce instability
International Nuclear Information System (INIS)
Klochkov, D.N.; Rukhadze, A.A.
1997-01-01
The radiative Pierce instability of a relativistic electron beam in a waveguide stabilized by an infinite strong magnetic field is considered. the increment and conditions for instability development in a wide interval of the beam currents are determined on the basis of the perturbation theory. It is shown that the instability has always the Raman character and is threshold less in current for the Pierce boundary conditions. It permits sufficiently strictly to define the instability saturation level from breaking the resonance condition and to estimate the radiation efficiency
Aeroelastic instability problems for wind turbines
DEFF Research Database (Denmark)
Hansen, Morten Hartvig
2007-01-01
This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical...... stiffness and chordwise position of the center of gravity along the blades are the main parameters for flutter. These instability characteristics are exemplified by aeroelastic stability analyses of different wind turbines. The review of each aeroelastic instability ends with a list of current research...... issues that represent unsolved aeroelostic instability problems for wind turbines. Copyright (c) 2007 John Wiley & Sons, Ltd....
Kwon, Dohyeon; Kim, Jungwon
2017-12-15
We report on all-fiber Michelson interferometer-based repetition-rate stabilization of femtosecond mode-locked lasers down to 1.3×10 -14 frequency instability and 1.4 fs integrated jitter in a 1 s time scale. The use of a compactly packaged 10 km long single-mode fiber (SMF)-28 fiber link as a timing reference allows the scaling of phase noise at a 10 GHz carrier down to -80 dBc/Hz at 1 Hz Fourier frequency. We also tested a 500 m long low-thermal-sensitivity fiber as a reference and found that, compared to standard SMF-28 fiber, it can mitigate the phase noise divergence by ∼10 dB/dec in the 0.1-1 Hz Fourier frequency range. These results suggest that the use of a longer low-thermal-sensitivity fiber may achieve sub-femtosecond integrated timing jitter with sub-10 -14 -level frequency instability in repetition rate by a simple and robust all-fiber-photonic method.
International Nuclear Information System (INIS)
Kusano, Tomohiro; Asamori, Koichi; Kurosawa, Hideki; Saito-Kokubu, Yoko; Tanikawa, Shin-ichi; Negi, Tateyuki; Hanamuro, Takahiro; Yasue, Ken-ichi; Yamasaki, Seiko; Yamada, Kunimi; Ishimaru, Tsuneari; Umeda, Koji
2011-01-01
This progress report (H22 Report) documents progress made during JAEA 1st Midterm Plan (FY 2005 - 2009) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. For the current 5-year R and D programme, three major goals have been defined as follows: 1) development and systematization of investigation techniques for selecting suitable sites in geosphere stability, 2) development, application and verification of prediction models for evaluating the changes of geological environment in thermal, hydraulic, mechanical and geochemical conditions for a long period of time, and 3) development of new dating techniques for providing information about geologic history and the timing of geologic events. For investigation techniques, an extracting technique of active faults with weak surface expressions by LiDAR, an integrated approach combining geophysical and geochemical methods for detecting crustal magma storage and an estimating method for uplift rates in an inland area using relative heights of fluvial terraces have been made. A numerical simulation code for predicting landform evolution in the next 100,000 years, and incorporating models of geophysical processes directly into probabilistic assessments for renewed volcanism using Bayesian inference (multiple inference model) have been prepared for prediction models. Improvement of AMS system for 14 C dating was conducted in order to precisely determine isotopic compositions. (U-Th)/He and K-Ar dating systems were also installed at Tono Geoscience Center (TGC) for determining the production age of fault gouge and precipitated within open fractures. In this paper, the current status of R and D activities with previous scientific and technological progress is summarized. (author)
Instability following total knee arthroplasty.
Rodriguez-Merchan, E Carlos
2011-10-01
Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and
Radiation-induced transgenerational instability.
Dubrova, Yuri E
2003-10-13
To date, the analysis of mutation induction has provided an irrefutable evidence for an elevated germline mutation rate in the parents directly exposed to ionizing radiation and a number of chemical mutagens. However, the results of numerous publications suggest that radiation may also have an indirect effect on genome stability, which is transmitted through the germ line of irradiated parents to their offspring. This review describes the phenomenon of transgenerational instability and focuses on the data showing increased cancer incidence and elevated mutation rates in the germ line and somatic tissues of the offspring of irradiated parents. The possible mechanisms of transgenerational instability are also discussed.
DEFF Research Database (Denmark)
Grembi, Veronica; Nannicini, Tommaso; Troiano, Ugo
2016-01-01
, the central government imposed fiscal rules on municipal governments, and in 2001 relaxed them below 5,000 inhabitants. We exploit the before/after and discontinuous policy variation, and show that relaxing fiscal rules increases deficits and lowers taxes. The effect is larger if the mayor can be reelected......Fiscal rules are laws aimed at reducing the incentive to accumulate debt, and many countries adopt them to discipline local governments. Yet, their effectiveness is disputed because of commitment and enforcement problems. We study their impact applying a quasi-experimental design in Italy. In 1999...
Directory of Open Access Journals (Sweden)
Gabriel Mursa
2014-08-01
Full Text Available The purpose of this article is to demonstrate that a common fiscal policy, designed to support the euro currency, has some significant drawbacks. The greatest danger is the possibility of leveling the tax burden in all countries. This leveling of the tax is to the disadvantage of countries in Eastern Europe, in principle, countries poorly endowed with capital, that use a lax fiscal policy (Romania, Bulgaria, etc. to attract foreign investment from rich countries of the European Union. In addition, common fiscal policy can lead to a higher degree of centralization of budgetary expenditures in the European Union.
Resistive instabilities in tokamaks
International Nuclear Information System (INIS)
Rutherford, P.H.
1985-10-01
Low-m tearing modes constitute the dominant instability problem in present-day tokamaks. In this lecture, the stability criteria for representative current profiles with q(0)-values slightly less than unit are reviewed; ''sawtooth'' reconnection to q(0)-values just at, or slightly exceeding, unity is generally destabilizing to the m = 2, n = 1 and m = 3, n = 2 modes, and severely limits the range of stable profile shapes. Feedback stabilization of m greater than or equal to 2 modes by rf heating or current drive, applied locally at the magnetic islands, appears feasible; feedback by island current drive is much more efficient, in terms of the radio-frequency power required, then feedback by island heating. Feedback stabilization of the m = 1 mode - although yielding particularly beneficial effects for resistive-tearing and high-beta stability by allowing q(0)-values substantially below unity - is more problematical, unless the m = 1 ideal-MHD mode can be made positively stable by strong triangular shaping of the central flux surfaces. Feedback techniques require a detectable, rotating MHD-like signal; the slowing of mode rotation - or the excitation of non-rotating modes - by an imperfectly conducting wall is also discussed
On some properties of longitudinal and transverse coupled-bunch instabilities
International Nuclear Information System (INIS)
Kamiya, Yukihide.
1983-02-01
Some properties of longitudinal and transverse coupled-bunch instabilities have been investigated theoretically and computationally, mainly based on a rigid-bunch model. In this report, we will study Robinson's stability, sum rules of the instabilities and the cure of instabilities by producing the oscillation frequencies different from bunch to bunch, and also give the numerical examples for KEK-PF storage ring. KEYWORD: storage ring, accelerator, bunched beam, longitudinal instability, transverse instability, coupled-bunch instability. (author)
Singer, Bart A.; Choudhari, Meelan; Li, Fei
1995-01-01
A multiple-scales approach is used to approximate the effects of nonparallelism and streamwise surface curvature on the growth of stationary crossflow vortices in incompressible, three-dimesional boundary layers. The results agree with results predicted by solving the parabolized stability equations in regions where the nonparallelism is sufficiently weak. As the nonparallelism increases, the agreement between the two approaches worsens. An attempt has been made to quantify the nonparallelism on flow stability in terms of a nondimensional number that describes the rate of change of the mean flow relative to the disturbance wavelength. We find that the above nondimensional number provides useful information about the adequacy of the multiple-scales approximation for different disturbances for a given flow geometry, but the number does not collapse data for different flow geometries onto a single curve.
Montgomery County of Maryland — This dataset includes the Fiscal Year 2015 Council-approved operating budget for Montgomery County. The dataset does not include revenues and detailed agency budget...
Pritha Mitra; Tigran Poghosyan
2015-01-01
Amid renewed crisis, falling tax revenues, and rising debt, Ukraine faces serious fiscal consolidation needs. Durable fiscal adjustment can support economic confidence and rebuild buffers but what is its overall impact on growth? How effective are revenue versus spending instruments? Does current or capital spending have a larger impact? Applying a structural vector autoregressive model, this paper finds that Ukraine’s near-term revenue and spending multipliers are well below one. In the medi...
Fiscal councils as a mechanism for establishing fiscal discipline
Directory of Open Access Journals (Sweden)
Anđelković Mileva
2014-01-01
Full Text Available Under the impact of the global economic crisis, the contemporary budget systems have been subject to extensive reforms. There is a growing number of scholars advocating the establishment of fully independent fiscal institutions which would be in charge of administering a sustainable fiscal policy. The bodies available in hitherto practice are fiscal councils, parliament committees on budgetary control or fiscal 'watchdogs'. The institutionalization of fiscal councils should provide for improving the quality of the public debate on fiscal policy and make the governments more fiscally accountable. The existing fiscal councils generally have an advisory role and they are expected to contribute to strengthening the role of national parliaments in scrutinizing the national budget. In fact, the establishment of fiscal councils ensues only after introducing the fiscal rules which serve as statutory limitations on the activities of the executive branch in the budget-related matters. The current economic crisis has substantially hindered the efficient application of these fiscal restrictions. Some states see the solution in establishing independent fiscal institutions which would control the compliance with these rules. As one of the participants in the budgetary process, fiscal councils are in a position to provide better information to the voters on the current state of affairs in public finances and (thus increase the political costs of the government's fiscal unaccountability. In practice, there are several models for the organization of fiscal councils which primarily focus on ex ante or ex post review and assessment concerning whether the relevant institutions have observed the fiscal rules and accomplished the fiscal goals. Considering that their role is to eliminate the asymmetry of information in relations between the legislative and executive breach of government, fiscal councils should contribute to reinforcing the legitimacy of the budgetary
Shoulder instability in professional football players.
Leclere, Lance E; Asnis, Peter D; Griffith, Matthew H; Granito, David; Berkson, Eric M; Gill, Thomas J
2013-09-01
Shoulder instability is a common problem in American football players entering the National Football League (NFL). Treatment options include nonoperative and surgical stabilization. This study evaluated how the method of treatment of pre-NFL shoulder instability affects the rate of recurrence and the time elapsed until recurrence in players on 1 NFL team. Retrospective cohort. Medical records from 1980 to 2008 for 1 NFL team were reviewed. There were 328 players included in the study who started their career on the team and remained on the team for at least 2 years (mean, 3.9 years; range, 2-14 years). The history of instability prior to entering the NFL and the method of treatment were collected. Data on the occurrence of instability while in the NFL were recorded to determine the rate and timing of recurrence. Thirty-one players (9.5%) had a history of instability prior to entering the NFL. Of the 297 players with no history of instability, 39 (13.1%) had a primary event at a mean of 18.4 ± 22.2 months (range, 0-102 months) after joining the team. In the group of players with prior instability treated with surgical stabilization, there was no statistical difference in the rate of recurrence (10.5%) or the timing to the instability episode (mean, 26 months) compared with players with no history of instability. Twelve players had shoulder instability treated nonoperatively prior to the NFL. Five of these players (41.7%) had recurrent instability at a mean of 4.4 ± 7.0 months (range, 0-16 months). The patients treated nonoperatively had a significantly higher rate of recurrence (P = 0.02) and an earlier time of recurrence (P = 0.04). The rate of contralateral instability was 25.8%, occurring at a mean of 8.6 months. Recurrent shoulder instability is more common in NFL players with a history of nonoperative treatment. Surgical stabilization appears to restore the rate and timing of instability to that of players with no prior history of instability.
Risk Factors as the Reasons of Political Instability
Directory of Open Access Journals (Sweden)
Георгий Ильич Марушко
2010-03-01
Full Text Available This article refers to the analysis of political instability and instability risk factors, and the mechanism of direct circuits and feedback between them. The best understanding of each of these factors conducts to comprehension of dynamics of change of stability of the state to external and internal sources of stabilization and destabilization.
Is There a Need for a New Fiscal Framework in the Euro Area?
DEFF Research Database (Denmark)
Hallett, Andrew Hughes; Hougaard Jensen, Svend E.
The rules stipulated by the Stability and Growth Pact have proved impossible to enforce. However, to avoid unsustainable fiscal policies reappearing, and to prevent monetary policy from being undermined by self-interested governments, there is still a need for a fiscal framework within the Euro...
Beetsma, R.M.W.J.; Bovenberg, A.L.
1995-01-01
This paper explores how decentralized, national fiscal policies interact with a common monetary policy in a monetary union. We show that fiscal policy plays a more important ro le in stabilizing country-specific shocks than with national monetary policies. Whereas monetary u nification with an
Doǧan, S.; Nixon, C. J.; King, A. R.; Pringle, J. E.
2018-05-01
Accretion discs are generally warped. If a warp in a disc is too large, the disc can `break' apart into two or more distinct planes, with only tenuous connections between them. Further, if an initially planar disc is subject to a strong differential precession, then it can be torn apart into discrete annuli that precess effectively independently. In previous investigations, torque-balance formulae have been used to predict where and when the disc breaks into distinct parts. In this work, focusing on discs with Keplerian rotation and where the shearing motions driving the radial communication of the warp are damped locally by turbulence (the `diffusive' regime), we investigate the stability of warped discs to determine the precise criterion for an isolated warped disc to break. We find and solve the dispersion relation, which, in general, yields three roots. We provide a comprehensive analysis of this viscous-warp instability and the emergent growth rates and their dependence on disc parameters. The physics of the instability can be understood as a combination of (1) a term that would generally encapsulate the classical Lightman-Eardley instability in planar discs (given by ∂(νΣ)/∂Σ < 0) but is here modified by the warp to include ∂(ν1|ψ|)/∂|ψ| < 0, and (2) a similar condition acting on the diffusion of the warp amplitude given in simplified form by ∂(ν2|ψ|)/∂|ψ| < 0. We discuss our findings in the context of discs with an imposed precession, and comment on the implications for different astrophysical systems.
Resistive instabilities in general toroidal plasma configurations
International Nuclear Information System (INIS)
Glasser, A.H.; Greene, J.M.; Johnson, J.L.
1975-01-01
Previous work by Johnson and Greene on resistive instabilities is extended to finite-pressure configurations. The Mercier criterion for the stability of the ideal magnetohydrodynamic interchange mode is rederived, the generalization of the earlier stability criterion for the resistive interchange mode is obtained, and a relation between the two is noted. Conditions for tearing mode instability are recovered with the growth rate scaling with the resistivity in a more complicated manner than eta 3 / 5 . Nyquist techniques are used to show that favorable average curvature can convert the tearing mode into an overstable mode and can often stabilize it
FISCALITY – RELEVANT FACTOR INFLUENCING THE BUSINESS ENVIRONMENT
Directory of Open Access Journals (Sweden)
Ionel MĂNDESCU
2013-06-01
Full Text Available Main tool for macroeconomic management - fiscal policy consists in establishing the levels of taxation and spending in order to influence macroeconomic performance. Fiscal policy, promoted by the government authorities of any contemporary state, is directed usually to achieving microeconomic and macroeconomic goals deriving from the roles the state must fulfill in the economy, respectively the allocative role, distributive, regulatory and the stabilizer role. Governmental authorities, through the production and supply of public goods that are financed at the expense of taxes or duties, or on the public debt, affect both individuals’ utility functions and production functions of economic agents in the private sector. At the macroeconomic level, fiscal policy decisions of governmental authorities relating to either public spending or taxation can be directed towards the stimulation of development. Fiscality is a business cost in investment, where the decisions are taken by representatives of the business environment.
Directory of Open Access Journals (Sweden)
Petar Kurecic
2017-06-01
Full Text Available This paper studies the relevance of political stability on foreign direct investment (FDI and the relevance of FDI on economic growth, in three panels. The first panel contains 11 very small economies; the second contains five well-developed and politically stable economies with highly positive FDI net inflows, while the third is a panel with economies that are prone to political violence or targeted by the terrorist attacks. We employ a Granger causality test and implement a vector autoregressive (VAR framework within the panel setting. In order to test the sensitivity of the results and avoid robust errors, we employ an ARDL model for each of the countries within every panel. Based upon our results, we conclude that there is a long-term relationship between political stability and FDI for the panel of small economies, while we find no empiric evidence of such a relationship for both panels of larger and more developed economies. Similarly to the original hypothesis of Lucas (1990, we find that FDI outflows tend to go towards politically less stable countries. On the other hand, the empiric methodology employed did not find such conclusive evidence in the panels of politically more developed countries or in the small economies that this paper observes.
Breaking the stability pact: was it predictable?
Bonatti, Luigi; Cristini, Annalisa
2007-01-01
We show analytically that the credibility problem which has affected the European Stability Pact originates from the insufficient distinction between two reasons for having binding fiscal constraints. The first reason deals with the governments’ tendency to neglect the effects of their fiscal policy on foreign governments (fiscal free-riding). The second reason follows from the governments’ tendency to raise debt by lowering taxes or increasing expenditures, and then to leave it to their succ...
Taamallah, Soufien
2015-01-01
© 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved. We investigate the onset of thermo-acoustic instabilities and their link to the mean flame configurations - or macrostructures - under acoustically coupled and decoupled conditions. Methane-hydrogen mixtures are used to explore the role of the fuel in changing the flame macrostructure, as determined by chemilumi-nescence, as the equivalence ratio (φ) varies. We observe four different configurations: a columnar flame (I); a bubble-columnar flame (II); a single conical flame (III); and a double conical flame (IV). We also observe different thermo-acoustic modes in the lean regime investigated, φ ∈ [0.5-0.75], that correspond to different flame configurations. By changing the combustor length without affecting the underlying flow, the resonant modes of the combustor are shifted to higher frequencies allowing for the decoupling of heat release fluctuations and the acoustic field over a range of equivalence ratio. We find that the same flame macrostructures observed in the long, acoustically coupled combustor arise in the short, acoustically decoupled combustor and transition at similar equivalence ratios in both combustors. The onset of the first fully unstable mode in the long combustor occurs at similar equivalence ratio as the flame transition from configuration III to IV. In the acoustically decoupled case, this transition occurs gradually starting with the intermittent appearance of a flame in the outer recirculation zone (ORZ). Spectral analysis of this phenomenon, referred to as "ORZ flame flickering" shows the existence of an unsteady event occurring over a narrow frequency band centered around 28 Hz along with a weaker broadband region at lower frequency in the range [1-10] Hz. The tone at 28 Hz is shown to be associated with the azimuthal advection of the flame by the outer recirculation zone flow. Changes in the fuel composition, by adding hydrogen (up to 20%), do not
International Nuclear Information System (INIS)
Carroll, Sean M.; Dulaney, Timothy R.; Gresham, Moira I.; Tam, Heywood
2009-01-01
We investigate the stability of theories in which Lorentz invariance is spontaneously broken by fixed-norm vector 'aether' fields. Models with generic kinetic terms are plagued either by ghosts or by tachyons, and are therefore physically unacceptable. There are precisely three kinetic terms that are not manifestly unstable: a sigma model (∂ μ A ν ) 2 , the Maxwell Lagrangian F μν F μν , and a scalar Lagrangian (∂ μ A μ ) 2 . The timelike sigma-model case is well defined and stable when the vector norm is fixed by a constraint; however, when it is determined by minimizing a potential there is necessarily a tachyonic ghost, and therefore an instability. In the Maxwell and scalar cases, the Hamiltonian is unbounded below, but at the level of perturbation theory there are fewer degrees of freedom and the models are stable. However, in these two theories there are obstacles to smooth evolution for certain choices of initial data.
Instabilities in electromagnetic quasilevitation.
Spragg, Kirk; Letout, Sebastien; Ernst, R; Sneyd, Alfred; Fautrelle, Yves
2014-05-01
We investigate free-surface instabilities occurring in various industrial processes involving liquid metal. Of particular interest is the behavior of the free surface of a pool of liquid metal when it is submitted to an alternating magnetic field. Experimentally, we study the effect of a vertical alternating medium-frequency magnetic field on an initially circular pool. We observe various types of behavior according to magnetic field amplitude, e.g., axisymmetric deformations, azimuthal mode structures, slow radial oscillation of the pool perimeter, and random rotation of the pool around its center. Drop rotation could be attributed to nonsymmetric shape deformations. The effect of oxidation leads to drastic changes in pool behavior. The experimental results are then compared to a linear stability analysis of the free surface of a circular liquid drop.
Fiscal Year 2014 Revegetation Assessment
Energy Technology Data Exchange (ETDEWEB)
Nordstrom, Jenifer [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-03-01
This report summarizes the Fiscal Year 2014 Revegetation Assessment by Battelle Energy Alliance, LLC. This assessment was conducted to document revegetation efforts at Idaho National Laboratory to ensure that disturbed vegetation and soil at various locations are being restored. This report provides the following information for each site being monitored by the Idaho National Laboratory Environmental Support and Services: • Summary of each site • Assessment of vegetation status and site stabilization at each location • Actions and Resolutions for each site. Five disturbed sites were evaluated for this assessment. Four sites are recommended to be removed from the annual assessment, and one is recommended for continued evaluation. New sites are also identified for future monitoring as part of the annual assessment.
Finite temperature instability for compactification
International Nuclear Information System (INIS)
Accetta, F.S.; Kolb, E.W.
1986-03-01
We consider finite temperature effects upon theories with extra dimensions compactified via vacuum stress energy (Casimir) effects. For sufficiently high temperature, a static configuration for the internal space is impossible. At somewhat lower temperatures, there is an instability due to thermal fluctuations of radius of the compact dimensions. For both cases, the Universe can evolve to a de Sitter-like expansion of all dimensions. Stability to late times constrains the initial entropy of the universe. 28 refs., 1 fig., 2 tabs
THE ESSENCE OF FISCAL MANAGEMENT
Carmen Comaniciu
2008-01-01
The existence of fiscal management determine the identification of the essential coordinates of it: the main objective; the sphere of action; essential characteristics; fundamental values; the main function; principles and legities. The essence of fiscal management represent its functions and on the basis of conceiving and exercising management from fiscality field resides an aggregate of principles. In this paper we will try to define the fiscal management, to identify the fundamental and sp...
Shaping the Fiscal Policy Framework
DEFF Research Database (Denmark)
Bergman, Ulf Michael; Hutchison, Michael M.; Hougaard Jensen, Svend E.
the international experiences with large-scale fiscal consolidations, including evidence on the expansionary fiscal contraction hypothesis with particular focus on the Danish experience in the early 1980s. Second, given the widespread perception that supranational fiscal rules have failed in Europe, we study...
Jeans instability in a quantum dusty magnetoplasma
International Nuclear Information System (INIS)
Salimullah, M.; Jamil, M.; Shah, H. A.; Murtaza, G.
2009-01-01
Jeans instability in a homogeneous cold quantum dusty plasma in the presence of the ambient magnetic field and the quantum effect arising through the Bohm potential has been examined using the quantum magnetohydrodynamic model. It is found that the Jeans instability is significantly reduced by the presence of the dust-lower-hybrid wave and the ion quantum effect. The minimum wavenumber for Jeans stability depends clearly on ion quantum effect and the dust-lower-hybrid frequency also.
Sectoral Diversification as Insurance against Economic Instability
Jan Kluge
2015-01-01
This paper examines the extent to which sectoral diversification can act as an insurance mechanism against fluctuations in regional gross value added growth rates. I apply portfolio theory to the growth-instability properties of German districts. Furthermore, I define a comprehensive diversification measure and use Stochastic Frontier Analysis in order to estimate whether diversification allows regions to achieve more efficient growth-instability combinations, i.e., greater stability at given...
Managing Hysteresis: Three Cornerstones to Fiscal Stability
Weeks, Richard
2012-01-01
The effects of the Great Recession of 2007-2009 continue to challenge school business officials (SBOs) and other education leaders as they strive to prepare students for the global workforce. Economists have borrowed a word from chemistry to describe this state of affairs: hysteresis--the lingering effects of the past on the present. Today's SBOs…
Tearing instability in cylindrical plasma configuration
International Nuclear Information System (INIS)
Zelenyj, L.M.
1979-01-01
The effect of the neutral-layer cylindrical geometry on the development of the tearing instability has been investigated in detail. The increments of the instability for all the regimes have been found. The influence of cylindrical effects becomes manifesting itself at small, as compared to the layer characteristic thickness, distances from the axis, and, finally, the electron regime of the instability development transforms into an ion one. The results obtained are of interest for studying the plasma stability in the devices of the ''Astron'' type and in magnetospheres of cosmic objects
The Causes of Fiscal Transparency
DEFF Research Database (Denmark)
Alt, James E.; Lassen, David Dreyer; Rose, Shanna
We use unique panel data on the evolution of transparent budget procedures in the American states over the past three decades to explore the political and economic determinants of fiscal transparency. Our case studies and quantitative analysis suggest that both politics and fiscal policy outcomes...... influence the level of transparency. More equal political competition and power sharing are associated with both greater levels of fiscal transparency and increases in fiscal transparency during the sample period. Political polarization and past fiscal conditions, in particular state government debt...... and budget imbalance, also appear to affect the level of transparency...
Fiscal Policy and Economic Growth in Nigeria
Directory of Open Access Journals (Sweden)
Sylvia Uchenna Agu
2015-11-01
Full Text Available This article aims at determining the impact of various components of fiscal policy on the Nigerian economy. We simply used descriptive statistics to show contribution of government fiscal policy to economic growth, and to ascertain and explain growth rates, and an ordinary least square (OLS in a multiple form to ascertain the relationship between economic growth and government expenditure components after ensuring data stationarity. Findings revealed that total government expenditures have tended to increase with government revenue, with expenditures peaking faster than revenue. Investment expenditures were much lower than recurrent expenditures evidencing the poor growth in the country’s economy. Hence, there is some evidence of positive correlation between government expenditure on economic services and economic growth. Therefore, in public spending, it is important to note that the effectiveness of the private sector depends on the stability and predictability of the public incentive framework, which promotes or crowds out private investment.
Cultural diversity, economic development and societal instability
Nettle, D.; Grace, J.B.; Choisy, M.; Cornell, H.V.; Guegan, J.-F.; Hochberg, M.E.
2007-01-01
Background. Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation on ?? diversity, but also diversity between a nation and its neighbours or ?? diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. Methodology/Principal Findings. We assembled a large cross-national dataset with information on ?? and ?? cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different type and domains of diversity have interacting effects. As previously documented, linguistic ?? diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For ?? diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious ?? diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Conclusions. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between, neighboring nations has the opposite effect, decreasing societal instability.
Cultural diversity, economic development and societal instability.
Nettle, Daniel; Grace, James B; Choisy, Marc; Cornell, Howard V; Guégan, Jean-François; Hochberg, Michael E
2007-09-26
Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation or alpha diversity, but also diversity between a nation and its neighbours or beta diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. We assembled a large cross-national dataset with information on alpha and beta cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different types and domains of diversity have interacting effects. As previously documented, linguistic alpha diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For beta diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious beta diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between neighboring nations has the opposite effect, decreasing societal instability.
Pathways towards instability in financial networks
Bardoscia, Marco; Battiston, Stefano; Caccioli, Fabio; Caldarelli, Guido
2017-02-01
Following the financial crisis of 2007-2008, a deep analogy between the origins of instability in financial systems and complex ecosystems has been pointed out: in both cases, topological features of network structures influence how easily distress can spread within the system. However, in financial network models, the details of how financial institutions interact typically play a decisive role, and a general understanding of precisely how network topology creates instability remains lacking. Here we show how processes that are widely believed to stabilize the financial system, that is, market integration and diversification, can actually drive it towards instability, as they contribute to create cyclical structures which tend to amplify financial distress, thereby undermining systemic stability and making large crises more likely. This result holds irrespective of the details of how institutions interact, showing that policy-relevant analysis of the factors affecting financial stability can be carried out while abstracting away from such details.
US fiscal regimes and optimal monetary policy
Mavromatis, K.
2014-01-01
Fiscal policy in the US has been documented to have been the leading authority in the ‘60s and the ‘70s (active fiscal policy), while committing to make the necessary fiscal adjustments following Volcker’s appointment (passive fiscal policy). Moreover, while passive, US fiscal policy has at times
Poelmann, E.
2016-01-01
In de fiscale literatuur en/of mediaberichten duikt met enige regelmaat de term ‘fishing expedition’ op. De term wordt in rechterlijke uitspraken en in beleid genoemd, in nationale en internationale context. Het valt op dat voor die term kennelijk slechts indirecte definities bestaan, althans ik heb
Consultatie bij fiscale wetgeving
Kreveld, Netty Margriet Amelien van
2016-01-01
The key objective of this research is to design a consultation model for the legislative process in fiscal matters. When tax laws are being drafted, such a model can be used as a tool to select the best possible consultation variant and the suitable stakeholders. I have analyzed six consultation
Instabilities in inhomogeneous plasma
International Nuclear Information System (INIS)
Mikhailovsky, A.B.
1983-01-01
The plasma inhomogeneity across the magnetic field causes a wide class of instabilities which are called instabilities of an inhomogeneous plasma or gradient instabilities. The instabilities that can be studied in the approximation of a magnetic field with parallel straight field lines are treated first, followed by a discussion of the influence of shear on these instabilities. The instabilities of a weakly inhomogeneous plasma with the Maxwellian velocity distribution of particles caused by the density and temperature gradients are often called drift instabilities, and the corresponding types of perturbations are the drift waves. An elementary theory of drift instabilities is presented, based on the simplest equations of motion of particles in the field of low-frequency and long-wavelength perturbations. Following that is a more complete theory of inhomogeneous collisionless plasma instabilities which uses the permittivity tensor and, in the case of electrostatic perturbations, the scalar of permittivity. The results are used to study the instabilities of a strongly inhomogeneous plasma. The instabilities of a plasma in crossed fields are discussed and the electromagnetic instabilities of plasma with finite and high pressure are described. (Auth.)
Composition driven structural instability in perovskite ferroelectrics
Directory of Open Access Journals (Sweden)
Chao Xu
2017-04-01
Full Text Available Ferroelectric solid solutions usually exhibit enhanced functional properties at the morphotropic phase boundary separating two ferroelectric phases with different orientations of polarization. The underlying mechanism is generally associated with polarization rotational instability and the flattened free energy profile. In this work we show that the polarization extensional instability can also be induced at the morphotropic phase boundary beyond the reported polar-nonpolar phase boundary. The piezoelectricity enhanced by this mechanism exhibits excellent thermal stability, which helps to develop high performance piezoelectric materials with good temperature stability.
Internal rotor friction instability
Walton, J.; Artiles, A.; Lund, J.; Dill, J.; Zorzi, E.
1990-01-01
The analytical developments and experimental investigations performed in assessing the effect of internal friction on rotor systems dynamic performance are documented. Analytical component models for axial splines, Curvic splines, and interference fit joints commonly found in modern high speed turbomachinery were developed. Rotor systems operating above a bending critical speed were shown to exhibit unstable subsynchronous vibrations at the first natural frequency. The effect of speed, bearing stiffness, joint stiffness, external damping, torque, and coefficient of friction, was evaluated. Testing included material coefficient of friction evaluations, component joint quantity and form of damping determinations, and rotordynamic stability assessments. Under conditions similar to those in the SSME turbopumps, material interfaces experienced a coefficient of friction of approx. 0.2 for lubricated and 0.8 for unlubricated conditions. The damping observed in the component joints displayed nearly linear behavior with increasing amplitude. Thus, the measured damping, as a function of amplitude, is not represented by either linear or Coulomb friction damper models. Rotordynamic testing of an axial spline joint under 5000 in.-lb of static torque, demonstrated the presence of an extremely severe instability when the rotor was operated above its first flexible natural frequency. The presence of this instability was predicted by nonlinear rotordynamic time-transient analysis using the nonlinear component model developed under this program. Corresponding rotordynamic testing of a shaft with an interference fit joint demonstrated the presence of subsynchronous vibrations at the first natural frequency. While subsynchronous vibrations were observed, they were bounded and significantly lower in amplitude than the synchronous vibrations.
Challenges to the Implementation of a New Framework for Safeguarding Financial Stability
Directory of Open Access Journals (Sweden)
Vlahović Ana
2014-09-01
Full Text Available There is probably no single economic concept that has attracted more attention and intrigued scientific and professional circles than financial stability. For over a decade now that have been efforts to establish the starting point in explaining this condition or characteristic of the financial system since some find that the key to defining financial stability lies in stability and others argue in favour of the opposite, instability. Unfortunately, no agreement has been reached on a universal definition that would be widely accepted at the international level. Consequently, this gave rise to open discussions on systemic risk, creating a framework for preserving financial stability, and the role of central banks in this process. This article analyses the results achieved in the development of a theoretical concept of financial stability and its practical implementation. A consensus has been reached on the necessity of removing rigid barriers between macro and prudential policies and on the necessity of their coordinated actions. The primary objectives of monetary and fiscal stability have been shifted towards preserving financial stability. The isolated macroprudential principle rightfully got the epithet of an archaic approach. Coordinated micro and macroprudential policies have definitely prevailed and become reality in many countries, including Montenegro. Created institutional frameworks for safeguarding financial stability at all levels - national, Pan-European and global - represent a challenge for further comparative studies.
Planning to cheat: EU fiscal policy in real time
Beetsma, R.; Giuliodori, M.; Wierts, P.
2009-01-01
Using real-time data from Europe's Stability and Convergence Programs, we explore how fiscal plans and their implementation in the EU are determined. We find that (1) implemented budgetary adjustment falls systematically short of planned adjustment and this shortfall increases with the projection
Fiscal Adjustment in IMF-Supported Adjustment Programmes: The ...
African Journals Online (AJOL)
Fiscal adjustment is an essential element of macro-economic stability and economic growth. Given that economic growth is the most powerful weapon in the fight for higher living standards, poor growth performance in African countries, has been a challenge to economists, policy makers and international development ...
RADIATIVE RAYLEIGH-TAYLOR INSTABILITIES
International Nuclear Information System (INIS)
Jacquet, Emmanuel; Krumholz, Mark R.
2011-01-01
We perform analytic linear stability analyses of an interface separating two stratified media threaded by a radiation flux, a configuration relevant in several astrophysical contexts. We develop a general framework for analyzing such systems and obtain exact stability conditions in several limiting cases. In the optically thin, isothermal regime, where the discontinuity is chemical in nature (e.g., at the boundary of a radiation pressure-driven H II region), radiation acts as part of an effective gravitational field, and instability arises if the effective gravity per unit volume toward the interface overcomes that away from it. In the optically thick a diabaticregime where the total (gas plus radiation) specific entropy of a Lagrangian fluid element is conserved, for example at the edge of radiation pressure-driven bubble around a young massive star, we show that radiation acts like a modified equation of state and derive a generalized version of the classical Rayleigh-Taylor stability condition.
Centrifugally Driven Rayleigh-Taylor Instability
Scase, Matthew; Hill, Richard
2017-11-01
The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.
On the instability increments of a stationary pinch
International Nuclear Information System (INIS)
Bud'ko, A.B.
1989-01-01
The stability of stationary pinch to helical modes is numerically studied. It is shown that in the case of a rather fast plasma pressure decrease to the pinch boundary, for example, for an isothermal diffusion pinch with Gauss density distribution instabilities with m=0 modes are the most quickly growing. Instability increments are calculated. A simple analytical expression of a maximum increment of growth of sausage instability for automodel Gauss profiles is obtained
Hydrodynamic instability of compressible fluid in porous medium
International Nuclear Information System (INIS)
Argal, Shraddha; Tiwari, Anita; Sharma, P K; Prajapati, R P
2014-01-01
The hydrodynamic Rayleigh -Taylor instability of two superposed compressible fluids in porous medium has been studied. The dispersion relation is derived for such a medium by using normal mode analysis. The RT instability is discussed for various simplified configuration. The effect of porosity and dynamic viscosity has been analyzed and it is observed that porosity and dynamic viscosity have stabilizing effect on the Rayleigh- Taylor instability of compressible fluids.
Numerical study of jets secondary instabilities
International Nuclear Information System (INIS)
Brancher, Pierre
1996-01-01
The work presented in this dissertation is a contribution to the study of the transition to turbulence in open shear flows. Results from direct numerical simulations are interpreted within the framework of hydrodynamic stability theory. The first chapter is an introduction to the primary and secondary instabilities observed in jets and mixing layers. The numerical method used in the present study is detailed in the second chapter. The dynamics of homogeneous circular jets subjected to stream wise and azimuthal perturbations are investigated in the third chapter. A complete scenario describing the evolution of the jet is proposed with emphasis on the dynamics of vorticity within the flow. In the fourth chapter a parametric study reveals a three-dimensional secondary instability mainly controlled in the linear regime by the Strouhal number of the primary instability. In the nonlinear regime the dynamics of the azimuthal harmonies are described by means of model equations and are linked to the formation of stream wise vortices in the braid. The fifth chapter is dedicated to the convective or absolute nature of the secondary instabilities in plane shear layers. It is shown that there are flow configurations for which the two-dimensional secondary instability (pairing) is absolute even though the primary instability (Kelvin-Helmholtz) is convective. Some preliminary results concerning the three-dimensional secondary instabilities arc presented at the end of this chapter. The last chapter summarizes the main results and examines possible extensions of this work. (author) [fr
Gravitational instability of thermally anisotropic plasma
International Nuclear Information System (INIS)
Singh, B.; Kalra, G.L.
1986-01-01
The equations of Chew, Goldberger, and Low (1956) modified to include the heat flux vector and self-gravitation are used to study the gravitational instability of unbounded plasma placed in a uniform static magnetic field. The linear stability analysis shows that some of the additional terms which arise as a result of higher moments are of the same order of magnitude as the terms in the original Chew, Goldberger, and Low theory. The influence of these terms on the gravitational instability has been specially examined. It is found that the gravitational instability sets in at a comparatively shorter wavelength and the growth rate is enhanced owing to the inclusion of these terms in the case where the propagation vector is along the magnetic field. The condition for instability is, however, unaltered when the direction of propagation is transverse to the direction of magnetic field. 19 references
The Growth Effects of Institutional Instability
DEFF Research Database (Denmark)
Berggren, Niclas; Bergh, Andreas; Bjørnskov, Christian
Both institutional quality and institutional stability have been argued to stimulate economic growth. But to improve institutional quality, a country must endure a period of institutional change, which implies at least a little and possibly a lot of institutional instability. We investigate...... the growth effects of institutional quality and instability, using the political risk index from the ICRG in a cross-country study of 132 countries, measuring instability as the coefficient of variation. Using the aggregate index, we find evidence that institutional quality is positively linked to growth....... While institutional instability is negatively related to growth in the baseline case, there are indications that the effect can be positive in rich countries, suggesting that institutional reform is not necessarily costly even during a transition period. Sensitivity analysis, e.g., decomposing...
FISCAL POLICY - AN INSTRUMENT FOR ACHIEVING ECONOMIC AND SOCIAL BALANCE
Directory of Open Access Journals (Sweden)
Alina Georgiana HOLT
2009-12-01
Full Text Available The fiscal policy construction developped at national level is focused on the maintenance of the macroeconomic stability process in order to achieve the nominal and real convergence criteria concerning the membership of the Romanian economy to the European Union integrated monetary space. The orientation of the fiscal national policy is subdue to some major constraints regarding her capacity of ensuring the external sustenance, of developping the non-inflation process, of forming and consolidating the financing resources necessary to the accomplishment of the post-adhesion engagements assumed by Romania as a member state of the European Union.
Genetic (in)stability in tomato
Wisman, E.
1993-01-01
In the present study tomato lines carrying unstable alleles of the loci yv or sulfurea were characterized. In addition, we aimed at the isolation of an endogenous transposable element supposedly active in the unstable lines. Since the unstable loci were not cloned, we
Fiscal Federalism in Monetary Unions
DEFF Research Database (Denmark)
Dreyer, Johannes Kabderian; A. Schmid, Peter
2015-01-01
Net fiscal transfers are commonly seen as a possible means to ensure the wellfunctioning of a currency area. We show that U.S. net fiscal transfers, measured as the difference between gross federal revenues and federal expenditures per state, are enormous. Moreover, we run panel regressions...... a system of fiscal federalism which raises the question whether it should be established in the medium- and long-run. If so, which should be the magnitude of net fiscal transfers? We calculate these transfers hypothetically for 1999-2010, using a relative volume comparable to the one in the USA....
Accountability report - fiscal year 1997
International Nuclear Information System (INIS)
1998-01-01
This document contains the US NRC's accountability report for fiscal year 1997. Topics include uses of funds, financial condition, program performance, management accountability, and the audited financial statement
Experimental study of the longitudinal instability for beam transport
International Nuclear Information System (INIS)
Reiser, M.; Wang, J.G.; Guo, W.M.; Wang, D.X.
1990-01-01
Theoretical model for beam longitudinal instability in a transport pipe with general wall impedance is considered. The result shows that a capacitive wall tends to stabilize the beam. The experimental study of the instability for a pure resistive-wall is presented, including the design parameters, setup and components for the experiment. 6 refs., 3 figs
Solitary Alfven wave envelopes and the modulational instability
International Nuclear Information System (INIS)
Kennel, C.F.
1987-06-01
The derivative nonlinear Schroedinger equation describes the modulational instability of circularly polarized dispersive Alfven wave envelopes. It also may be used to determine the properties of finite amplitude localized stationary wave envelopes. Such envelope solitons exist only in conditions of modulational stability. This leaves open the question of whether, and if so, how, the modulational instability produces envelope solitons. 12 refs
Thermal instabilities in low-mass subgiants?
International Nuclear Information System (INIS)
Von Rudloff, I.R.; Vandenberg, D.A.; Hartwick, F.D.A.
1988-01-01
The thermal stability of evolving stars in globular clusters has been examined in order to determine whether or not gaps and the observationally inferred deep mixing near the base of the red-giant branch can be explained in terms of an instability of the hydrogen-burning shell. The results of this investigation are that, in agreement with previous suggestions, the greatest potential for such an instability occurs just at the point where a star begins to ascend the giant branch - i.e., where gaps are seen in some systems - but, in contrast with earlier predictions, the standard models do not actually become unstable. However, from all indications, the stability is believed to be marginal, and it is suggested that rotation, which has now been observed in some globulars, may be the mechanism by which an instability is produced. 36 references
Edge instability in incompressible planar active fluids
Nesbitt, David; Pruessner, Gunnar; Lee, Chiu Fan
2017-12-01
Interfacial instability is highly relevant to many important biological processes. A key example arises in wound healing experiments, which observe that an epithelial layer with an initially straight edge does not heal uniformly. We consider the phenomenon in the context of active fluids. Improving upon the approximation used by Zimmermann, Basan, and Levine [Eur. Phys. J.: Spec. Top. 223, 1259 (2014), 10.1140/epjst/e2014-02189-7], we perform a linear stability analysis on a two-dimensional incompressible hydrodynamic model of an active fluid with an open interface. We categorize the stability of the model and find that for experimentally relevant parameters, fingering instability is always absent in this minimal model. Our results point to the crucial role of density variation in the fingering instability in tissue regeneration.
Early Prevention Method for Power Systems Instability
DEFF Research Database (Denmark)
Dmitrova, Evgenia
containing no voltage sources). The main functionality of the early prevention method is to deliver control solution allowing escape from instability on the basis of data obtained by PMU measurements. The developed algorithm performs identification of the optimal node for countermeasure application...... instability was created. Utilizing synthetic PMU data, the early prevention method proposed a location and an amount of the countermeasure which will prevent instability; the prediction of the resulting stability margins corresponding to application of the suggested countermeasure was carried out....... The predicted effect of the suggested countermeasure application is in a good agreement with the results obtained by RMS dynamic simulation. Developed method enables adaptive preventive control for near real-time stability maintenance. The achieved results are opening promising perspective for power system...
Ashish Chaturvedi; Manjeet S. Saluja; Abhijit Banerjee; Rachna Arora
2014-01-01
The paper presents concepts and instruments of environmental fiscal reforms (EFR) and their application in the Indian context. EFR can lead to environmental improvement more efficiently and cost effectively than traditional regulation. There is substantial experience of successful EFR implementation in the European Union. India has also adopted some EFR measures such as deregulation of petrol prices, coal cess, and subsidy for setting up common effluent treatment plants. The challenges of imp...
Elastocapillary Instability in Mitochondrial Fission
Gonzalez-Rodriguez, David; Sart, Sébastien; Babataheri, Avin; Tareste, David; Barakat, Abdul I.; Clanet, Christophe; Husson, Julien
2015-08-01
Mitochondria are dynamic cell organelles that constantly undergo fission and fusion events. These dynamical processes, which tightly regulate mitochondrial morphology, are essential for cell physiology. Here we propose an elastocapillary mechanical instability as a mechanism for mitochondrial fission. We experimentally induce mitochondrial fission by rupturing the cell's plasma membrane. We present a stability analysis that successfully explains the observed fission wavelength and the role of mitochondrial morphology in the occurrence of fission events. Our results show that the laws of fluid mechanics can describe mitochondrial morphology and dynamics.
Strengthening Strategic Stability with Russia
2017-01-01
political stabil - ity. From the current Russian perspective, both of these compo- nents were thrown out of balance in the 1990s, creating instability ...part of the United States in the early 2000s, stra- tegic stability was replaced with instability and military- political defeats for Russia.27...overall strategic balance of the world political system.8 (As discussed later, the official Russian definition of strategic stability is broadening in
Instability and Change in Collective Bargaining
DEFF Research Database (Denmark)
Brandl, Bernd; Ibsen, Christian Lyhne
2017-01-01
Previous studies on collective bargaining structures and macroeconomic performance have largely ignored the role of stable and instable institutional structures and the effects of institutional change itself. In this article we posit that institutional stability of collective bargaining is of maj...... following the change. This effect also holds for changes in both decentralization and centralization of institutions....
Physics-Based Pneumatic Hammer Instability Model, Phase II
National Aeronautics and Space Administration — The objective of this project is to develop a physics-based pneumatic hammer instability model that accurately predicts the stability of hydrostatic bearings...
International Nuclear Information System (INIS)
2000-04-01
This program showed details on the research and examination program of the Japan Nuclear Cycle Development Institute to be carried out at the Tono Mines in the Heisei 12 fiscal year, according to the 'Fundamental program on research and examinations at the Tono Mines' established on October, 1998. And, this program is carried out under an aim at understanding of transfer and delay performance of materials in deposit rocks with uranium and geological features such as fault, and at development of technology and apparatus for general investigation and evaluation of geological environment, as a stratum science research. Here were described on research and examination of mechanical stability on the rock board, research and examination of geological environment around a tunnel, research and examination of material transfer in the rock board, and research and examination of the Tsukiyoshi stratum abstractly before 1999 and in details at 2000 fiscal years. (G.K.)
CAPITALIZATION OF FISCAL AND ACCOUNTING INTERFERENCES FOR FISCAL OPTIMIZATION
Directory of Open Access Journals (Sweden)
Dănuţ CHILAREZ
2014-06-01
Full Text Available As economic entities in Romania are still in a relationship of interdependence between the accounting interest and the fiscal one, it makes the application of one or another accounting treatment under different circumstances on the transactions specific to the activity have a certain influence on the information released by the financial statements, but also on the tax bases and hence on the fiscal cost. This article argues that the sustainability and performance of a business requires, in addition to the effective management of the economic and financial resources in order to maximise performance and to ensure the cash flows, that the management must take into account both the good informing of the information users through the financial statements, and proper management of the fiscal implications in order to record a fiscal cost as low as possible while respecting the legal framework so that the fiscal risk is avoided or reduced as much as possible.
Gherman Anca Maria; Huru Dragos
2008-01-01
The concept related to currency stability includes internal currency stability as intern price stability, the money demand and supply stability and the stability of the interest rate. Also it includes external currency stability through exchange rate mechanism. The equilibrium of national economy is determined by the evolution of inflation and by the evolution of nominal exchange rate mechanism as an expression of external stability.
Diffusive instabilities in hyperbolic reaction-diffusion equations
Zemskov, Evgeny P.; Horsthemke, Werner
2016-03-01
We investigate two-variable reaction-diffusion systems of the hyperbolic type. A linear stability analysis is performed, and the conditions for diffusion-driven instabilities are derived. Two basic types of eigenvalues, real and complex, are described. Dispersion curves for both types of eigenvalues are plotted and their behavior is analyzed. The real case is related to the Turing instability, and the complex one corresponds to the wave instability. We emphasize the interesting feature that the wave instability in the hyperbolic equations occurs in two-variable systems, whereas in the parabolic case one needs three reaction-diffusion equations.
Flow-Induced Instabilities in Pump-Turbines in China
Directory of Open Access Journals (Sweden)
Zhigang Zuo
2017-08-01
Full Text Available The stability of pump-turbines is of great importance to the operation of pumped storage power (PSP stations. Both hydraulic instabilities and operational instabilities have been reported in PSP stations in China. In order to provide a reference to the engineers and scientists working on pump-turbines, this paper summarizes the hydraulic instabilities and performance characteristics that promote the operational instabilities encountered in pump-turbine operations in China. Definitions, analytical methods, numerical and experimental studies, and main results are clarified. Precautions and countermeasures are also provided based on a literature review. The gaps between present studies and the need for engineering practice are pointed out.
Fiscal councils and economic volatility
Czech Academy of Sciences Publication Activity Database
Geršl, A.; Jašová, M.; Zápal, Jan
2014-01-01
Roč. 64, č. 3 (2014), s. 190-212 ISSN 0015-1920 Grant - others:UK(CZ) UNCE 204005/2012 Institutional support: PRVOUK-P23 Keywords : dynamic inconsistency * fiscal and monetary policy interaction * independent fiscal council Subject RIV: AH - Economic s Impact factor: 0.420, year: 2014 http://journal.fsv.cuni.cz/storage/1298_jasova.pdf
Deepening Representative Democracy through Fiscal ...
African Journals Online (AJOL)
The ideas behind composite budgeting for effective fiscal decentralisation are noble, but the implementation is constrained by organisational, coordination, structural and technical factors. The key unanswered question is whether the failure to deliver the goods of fiscal decentralisation is fettered by misnomer ...
MHD instabilities in astrophysical plasmas: very different from MHD instabilities in tokamaks!
Goedbloed, J. P.
2018-01-01
The extensive studies of MHD instabilities in thermonuclear magnetic confinement experiments, in particular of the tokamak as the most promising candidate for a future energy producing machine, have led to an ‘intuitive’ description based on the energy principle that is very misleading for most astrophysical plasmas. The ‘intuitive’ picture almost directly singles out the dominant stabilizing field line bending energy of the Alfvén waves and, consequently, concentrates on expansion schemes that minimize that contribution. This happens when the wave vector {{k}}0 of the perturbations, on average, is perpendicular to the magnetic field {B}. Hence, all macroscopic instabilities of tokamaks (kinks, interchanges, ballooning modes, ELMs, neoclassical tearing modes, etc) are characterized by satisfying the condition {{k}}0 \\perp {B}, or nearly so. In contrast, some of the major macroscopic instabilities of astrophysical plasmas (the Parker instability and the magneto-rotational instability) occur when precisely the opposite condition is satisfied: {{k}}0 \\parallel {B}. How do those instabilities escape from the dominance of the stabilizing Alfvén wave? The answer to that question involves, foremost, the recognition that MHD spectral theory of waves and instabilities of laboratory plasmas could be developed to such great depth since those plasmas are assumed to be in static equilibrium. This assumption is invalid for astrophysical plasmas where rotational and gravitational accelerations produce equilibria that are at best stationary, and the associated spectral theory is widely, and incorrectly, believed to be non-self adjoint. These complications are addressed, and cured, in the theory of the Spectral Web, recently developed by the author. Using this method, an extensive survey of instabilities of astrophysical plasmas demonstrates how the Alfvén wave is pushed into insignificance under these conditions to give rise to a host of instabilities that do not
Did Fiscal Stimulus Lift Developing Asia Out of the Global Crisis? An Empirical Investigation
Directory of Open Access Journals (Sweden)
Seok-Kyun Hur
2018-03-01
Full Text Available The substantial slowdown of economic growth since the global financial crisis of 2008-2009 is rekindling debate on whether developing Asia should use fiscal expansion to boost aggregate demand. A key factor in the debate is the effectiveness of countercyclical fiscal policy in the region. The global crisis, as well as the fiscal stimulus packages implemented by developing Asian countries at that time, give some clues to this important issue. The region weathered the global crisis well and experienced a robust V-shaped recovery. According to conventional wisdom, the fiscal stimulus packages put in place by Asian governments played a key role in the region’s recovery. The central objective of this paper is to empirically test this wisdom by using cross-country panel data. Our main finding is that the stimulus has had a limited but positive impact on developing Asia’s output during the global crisis. This lends some support to the notion that countercyclical fiscal policy can help the region cope with severe external shocks. The broader, more fundamental implication for regional policymakers is that the region’s long-standing commitment to fiscal discipline can yield significant benefits beyond macroeconomic stability. An important consequence of this commitment - relatively healthy fiscal balance sheets - enabled the region’s governments to quickly and decisively embark upon fiscal stimulus programs.
Is the Fiscal Policy of the Czech Republic Pro-cyclical?
Directory of Open Access Journals (Sweden)
Martin Rolák
2015-01-01
Full Text Available The main goal of this paper is to analyse whether the fiscal policy of the Czech Republic is anti-cyclical. This analysis is carried out through decomposing the government’s balance into its cyclical and structural part. The first differences of the structural part are then put in relation to the output gap to determine whether the fiscal policy is pro- or anti-cyclical. Moreover, the correlation of government expenditures and revenues with the business cycle is also subject of our analysis. We also examine whether the fiscal rules which the Czech Republic would have to adhere to once it enters the euro area limit fiscal policy as a stabilizing mechanism.The paper concludes that the fiscal policy in the Czech Republic was for the most part rather of a random character than anti-cyclical during the examined period 1998–2013. This conclusion has two implications. Firstly, there is still room for improvement in fully and consistently utilizing fiscal policy to stabilise the Czech economy throughout economic cycles. Secondly, fiscal rules would not limit the Czech government to practice anti-cyclical fiscal policy if they have been implemented since 1998.
Combustion instability modeling and analysis
Energy Technology Data Exchange (ETDEWEB)
Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering
1995-12-31
It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.
Coherent Instabilities of ILC Damping Ring
Energy Technology Data Exchange (ETDEWEB)
Heifets, S.; Stupakov, G.; Bane, K.; /SLAC
2006-09-27
The paper presents the first attempt to estimates the ILC damping ring impedance and compare thresholds of the classical instabilities for several designs initially proposed for the DR. The work was carried out in the spring of 2006. Since then the choice of the DR is narrowed. Nevertheless, the analysis described may be useful for the next iterations of the beam stability. Overall, the conventional instabilities will have little impact on the ring performance provided the careful design of the ring minimizes the impedance below acceptable level indicated above. The only exception is the transverse CB instability. The longitudinal CB is less demanding. However, even the transverse CB instability would have threshold current above nominal provided the aperture in the wigglers is increased from 8 mm to 16 mm. The microwave instability needs more studies. Nevertheless, we should remember that the ILC DR is different from existing high-current machines at least in two respects: absence of the beam-beam tune spread stabilizing beams in colliders, and unusual strict requirements for low emittance. That may cause new problems such as bunch emittance dilution due to high-frequency wakes (BPMs, grooves), etc. Even if such a possibility exists, it probably universal for all machines and ought be addressed in the design of vacuum components rather than have effect on the choice of the machine design.
Hydrodynamic instabilities in inertial fusion
International Nuclear Information System (INIS)
Hoffman, N.M.
1994-01-01
This report discusses topics on hydrodynamics instabilities in inertial confinement: linear analysis of Rayleigh-Taylor instability; ablation-surface instability; bubble rise in late-stage Rayleigh-Taylor instability; and saturation and multimode interactions in intermediate-stage Rayleigh-Taylor instability
the fiscality, tool of an energy policy
International Nuclear Information System (INIS)
2001-12-01
This report studies how the fiscality can be an adapted tool for the implementing of the french energy policy. The term fiscality designates here the fiscality of the energy production, consumption and use in the industrial fabrication processes. An evaluation of the french fiscality and the analysis of this accounting are detailed. (A.L.B.)
[Capsular retensioning in anterior unidirectional glenohumeral instability].
Benítez Pozos, Leonel; Martínez Molina, Oscar; Castañeda Landa, Ezequiel
2007-01-01
To present the experience of the Orthopedics Service PEMEX South Central Hospital in the management of anterior unidirectional shoulder instability with an arthroscopic technique consisting of capsular retensioning either combined with other anatomical repair procedures or alone. Thirty-one patients with anterior unidirectional shoulder instability operated-on between January 1999 and December 2005 were included. Fourteen patients underwent capsular retensioning and radiofrequency, and in 17 patients, capsular retensioning was combined with suture anchors. Patients with a history of relapsing glenohumeral dislocations and subluxations, with anterior instability with or without associated Bankart lesions were selected; all of them were young. The results were assessed considering basically the occurrence of instability during the postoperative follow-up. No cases of recurring instability occurred. Two cases had neuroma and one experienced irritation of the suture site. Six patients had residual limitation of combined lateral rotation and abduction movements, of a mean of 10 degrees compared with the healthy contralateral side. The most frequent incident was the leak of solutions to the soft tissues. Capsular retensioning, whether combined or not with other anatomical repair techniques, has proven to result in a highly satisfactory rate of glenohumeral stabilization in cases of anterior unidirectional instabilities. The arthroscopic approach offers the well-known advantages of causing less damage to the soft tissues, and a shorter time to starting rehabilitation therapy and exercises.
Influence of continuously-varing profile on the diocotron instability in a non neutral plasma column
International Nuclear Information System (INIS)
Asgary, H. R.; Maraghehechi, Behrooz; Rafii, Mahboobeh
2003-01-01
In this paper we investigate the theoretical method related to density profile effect on diocotron instability in nonrelativistic state in non neutral plasma column. At first we introduce non neutral plasma and diocotron instability then we extract instability equation and we will investigate plasma stability with special profile density
Directory of Open Access Journals (Sweden)
Ashish Chaturvedi
2014-09-01
Full Text Available The paper presents concepts and instruments of environmental fiscal reforms (EFR and their application in the Indian context. EFR can lead to environmental improvement more efficiently and cost effectively than traditional regulation. There is substantial experience of successful EFR implementation in the European Union. India has also adopted some EFR measures such as deregulation of petrol prices, coal cess, and subsidy for setting up common effluent treatment plants. The challenges of implementing EFR measures in India are also discussed, including inadequate analysis, policy framework and institutional capacity, as well as conflict with poverty reduction and building political support.
The Role for Discretionary Fiscal Policy in a Low Interest Rate Environment
Martin Feldstein
2002-01-01
Although there is now widespread agreement in the economics profession that discretionary counter-cyclical'fiscal policy has not contributed to economic stability and may have actually been destabilizing at particular times in the past, there is one important condition when discretionary fiscal policy can play a constructive role: in a sustained downturn when aggregate demand and interest rates are low and when prices are falling or may soon be falling. This short note begins by summarizing t...
Dynamical instability of a charged gaseous cylinder
Sharif, M.; Mumtaz, Saadia
2017-10-01
In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.
STRUCTURAL STRESS RELAXATION IN STAINLESS INSTABILITY STEEL
Directory of Open Access Journals (Sweden)
S. Lyabuk
2017-06-01
Full Text Available The approach to the description of conditions of martensitic transformation in austenitic steel is advanced. Transformation induced hardening is the result of Le Chatelier principle in instability alloys. The phase transformation in austenitic instability stainless steel is the cause of reduction of grain refining and increase of strength. It was experimentally shown that physical-mechanical characteristics of the prepared materials were defined by the structure and inhomogeneous distribution of the hardening phase within a grain. The reasons for high thermal stability of inverse austenitic were established. The factors determining the inverse austenitic relaxation resistibility and resources for its increasing were revealed.
Genome instability: Linking ageing and brain degeneration.
Barzilai, Ari; Schumacher, Björn; Shiloh, Yosef
2017-01-01
Ageing is a multifactorial process affected by cumulative physiological changes resulting from stochastic processes combined with genetic factors, which together alter metabolic homeostasis. Genetic variation in maintenance of genome stability is emerging as an important determinant of ageing pace. Genome instability is also closely associated with a broad spectrum of conditions involving brain degeneration. Similarities and differences can be found between ageing-associated decline of brain functionality and the detrimental effect of genome instability on brain functionality and development. This review discusses these similarities and differences and highlights cell classes whose role in these processes might have been underestimated-glia and microglia. Copyright © 2016. Published by Elsevier B.V.
Efficiency Versus Instability in Plasma Accelerators
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Valeri [Fermilab; Burov, Alexey [Fermilab; Nagaitsev, Sergei [Fermilab
2017-01-05
Plasma wake-field acceleration in a strongly nonlinear (a.k.a. the blowout) regime is one of the main candidates for future high-energy colliders. For this case, we derive a universal efficiency-instability relation, between the power efficiency and the key instability parameter of the witness bunch. We also show that in order to stabilize the witness bunch in a regime with high power efficiency, the bunch needs to have high energy spread, which is not presently compatible with collider-quality beam properties. It is unclear how such limitations could be overcome for high-luminosity linear colliders.
Analysis of microscopic instability for rotating LIB
International Nuclear Information System (INIS)
Seto, Masaru; Niu, Keishiro
1985-01-01
The instability of a neutral hollow beam is investigated within the framework of the Vlasov-Maxwell equations. It is assumed that the hollow beam is thin with the radial thickness a which is much smaller than the major radius R 0 , and that the equilibrium beam charge is neutralized by the background electron charge. The stability analysis is carried out for perturbations about the beam equilibrium distribution function fsub(b) 0 . The detailed instability properties are calculated for a variety of system parameters. (author)
Anisotropic instability in a laser heated plasma
International Nuclear Information System (INIS)
Sangam, A.; Morreeuw, J.-P.; Tikhonchuk, V. T.
2007-01-01
The theory of the Weibel instability induced by the inverse Bremsstrahlung absorption of a laser light in an underdense plasma is revisited. It is shown that previous analyses have strongly overestimated the effect by neglecting the stabilizing term related to the interaction of the generated quasistatic magnetic field with the laser-heated electrons. The revised model leads to a reduction of the growth rate by more than a factor of 10, to strong reduction of the domain of unstable modes and to inversion of the direction of the unstable wave vectors in the long wavelength limit. The consequences of this instability on the laser plasma interaction are also discussed
Double Arc Instability in the Solar Corona
Energy Technology Data Exchange (ETDEWEB)
Ishiguro, N.; Kusano, K., E-mail: n-ishiguro@isee.nagoya-u.ac.jp [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 Japan (Japan)
2017-07-10
The stability of the magnetic field in the solar corona is important for understanding the causes of solar eruptions. Although various scenarios have been suggested to date, the tether-cutting reconnection scenario proposed by Moore et al. is one of the widely accepted models to explain the onset process of solar eruptions. Although the tether-cutting reconnection scenario proposes that the sigmoidal field formed by internal reconnection is the magnetic field in the pre-eruptive state, the stability of the sigmoidal field has not yet been investigated quantitatively. In this paper, in order to elucidate the stability problem of the pre-eruptive state, we developed a simple numerical analysis in which the sigmoidal field is modeled by a double arc electric current loop and its stability is analyzed. As a result, we found that the double arc loop is more easily destabilized than the axisymmetric torus, and it becomes unstable even if the external field does not decay with altitude, which is in contrast to the axisymmetric torus instability. This suggests that tether-cutting reconnection may well work as the onset mechanism of solar eruptions, and if so, the critical condition for eruption under a certain geometry may be determined by a new type of instability rather than by the torus instability. Based on them, we propose a new type of instability called double arc instability (DAI). We discuss the critical conditions for DAI and derive a new parameter κ , defined as the product of the magnetic twist and the normalized flux of the tether-cutting reconnection.
A numerical and analytical investigation of Rayleigh-Taylor instability in a solid tungsten plate
International Nuclear Information System (INIS)
Robinson, A.C.; Swegle, J.W.
1987-07-01
The Rayleigh-Taylor instability response of an elastic-plastic tungsten plate is investigated by numerical experiments and an approximate modal analysis. The so-called ''minimum amplitude'' instability criteria derived from plasticity analyses is shown to be incomplete as a general indicator of instability or stability at very large driving pressures. Model equations are derived which are able to reproduce the basic qualitative features of the observed instability response given by the numerical calculations. 11 refs., 29 figs
Control of the vertical instability in tokamaks
International Nuclear Information System (INIS)
Lazarus, E.A.; Lister, J.B.; Neilson, G.H.
1989-05-01
The problem of control of the vertical instability is formulated for a massless filamentary plasma. The massless approximation is justified by an examination of the role of inertia in the control problem. The system is solved using Laplace transform techniques. The linear system is studied to determine the stability boundaries. It is found that the system can be stabilized up to a critical decay index, which is predominantly a function of the geometry of the passive stabilizing shell. A second, smaller critical index, which is a function of the geometry of the control coils, determines the limit of stability in the absence of derivative gain in the control circuit. The system is also studied numerically in order to incorporate the non-linear effects of power supply dynamics. The power supply bandwidth requirement is determined by the open-loop growth rate of the instability. The system is studied for a number of control coil options which are available on the DIII-D tokamak. It is found that many of the coils will not provide adequate stabilization and that the use of inboard coils is advantageous in stabilizing the system up to the critical index. Experiments carried out on DIII-D confirm the appropriateness of the model. Using the results of the model study, we have stabilized DIII-D plasmas with decay indices up to 98% of the critical index. Measurement of the plasma vertical position is also discussed. (author) 27 figs., 6 refs
Fiscal Liability of State Contractors
Directory of Open Access Journals (Sweden)
Santiago Fajardo-Peña
2017-06-01
Full Text Available The State contract is one of the most important tools for public management. The formation, execution and liquidation of State contracts are also a potential cause of State patrimonial damages. Perhaps for this reason, many State contractors are prosecuted as if they were public spending managers. The question, however, is not as simple. The fiscal liability process has a qualified recipient: the fiscal manager. In this article, through a conceptual exposition and a case study, we identify the criterion for determining in which cases a State contractor acquires the function of controlling public funds and when he/she can be subjected to a fiscal liability.
Tearing instabilities in turbulence
International Nuclear Information System (INIS)
Ishizawa, A.; Nakajima, N.
2009-01-01
Full text: Effects of micro-turbulence on tearing instabilities are investigated by numerically solving a reduced set of two-fluid equations. Micro-turbulence excites both large-scale and small-scale Fourier modes through energy transfer due to nonlinear mode coupling. The energy transfer to large scale mode does not directly excite tearing instability but it gives an initiation of tearing instability. When tearing instability starts to grow, the excited small scale mode plays an important role. The mixing of magnetic flux by micro-turbulence is the dominant factor of non-ideal MHD effect at the resonant surface and it gives rise to magnetic reconnection which causes tearing instability. Tearing instabilities were investigated against static equilibrium or flowing equilibrium so far. On the other hand, the recent progress of computer power allows us to investigate interactions between turbulence and coherent modes such as tearing instabilities in magnetically confined plasmas by means of direct numerical simulations. In order to investigate effects of turbulence on tearing instabilities we consider a situation that tearing mode is destabilized in a quasi-equilibrium including micro-turbulence. We choose an initial equilibrium that is unstable against kinetic ballooning modes and tearing instabilities. Tearing instabilities are current driven modes and thus they are unstable for large scale Fourier modes. On the other hand kinetic ballooning modes are unstable for poloidal Fourier modes that are characterized by ion Larmor radius. The energy of kinetic ballooning modes spreads over wave number space through nonlinear Fourier mode coupling. We present that micro-turbulence affects tearing instabilities in two different ways by three-dimensional numerical simulation of a reduced set of two-fluid equations. One is caused by energy transfer to large scale modes, the other is caused by energy transfer to small scale modes. The former is the excitation of initial
Directory of Open Access Journals (Sweden)
Gherman Anca Maria
2008-05-01
Full Text Available The concept related to currency stability includes internal currency stability as intern price stability, the money demand and supply stability and the stability of the interest rate. Also it includes external currency stability through exchange rate mechanism. The equilibrium of national economy is determined by the evolution of inflation and by the evolution of nominal exchange rate mechanism as an expression of external stability.
CAPITALIZATION OF FISCAL AND ACCOUNTING INTERFERENCES FOR FISCAL OPTIMIZATION
Dănuţ CHILAREZ; George Sebastian ENE
2014-01-01
As economic entities in Romania are still in a relationship of interdependence between the accounting interest and the fiscal one, it makes the application of one or another accounting treatment under different circumstances on the transactions specific to the activity have a certain influence on the information released by the financial statements, but also on the tax bases and hence on the fiscal cost. This article argues that the sustainability and performance of a business requi...
Bernstein instability driven by thermal ring distribution
Energy Technology Data Exchange (ETDEWEB)
Yoon, Peter H., E-mail: yoonp@umd.edu [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Hadi, Fazal; Qamar, Anisa [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan)
2014-07-15
The classic Bernstein waves may be intimately related to banded emissions detected in laboratory plasmas, terrestrial, and other planetary magnetospheres. However, the customary discussion of the Bernstein wave is based upon isotropic thermal velocity distribution function. In order to understand how such waves can be excited, one needs an emission mechanism, i.e., an instability. In non-relativistic collision-less plasmas, the only known Bernstein wave instability is that associated with a cold perpendicular velocity ring distribution function. However, cold ring distribution is highly idealized. The present Brief Communication generalizes the cold ring distribution model to include thermal spread, so that the Bernstein-ring instability is described by a more realistic electron distribution function, with which the stabilization by thermal spread associated with the ring distribution is demonstrated. The present findings imply that the excitation of Bernstein waves requires a sufficiently high perpendicular velocity gradient associated with the electron distribution function.
Bernstein instability driven by thermal ring distribution
International Nuclear Information System (INIS)
Yoon, Peter H.; Hadi, Fazal; Qamar, Anisa
2014-01-01
The classic Bernstein waves may be intimately related to banded emissions detected in laboratory plasmas, terrestrial, and other planetary magnetospheres. However, the customary discussion of the Bernstein wave is based upon isotropic thermal velocity distribution function. In order to understand how such waves can be excited, one needs an emission mechanism, i.e., an instability. In non-relativistic collision-less plasmas, the only known Bernstein wave instability is that associated with a cold perpendicular velocity ring distribution function. However, cold ring distribution is highly idealized. The present Brief Communication generalizes the cold ring distribution model to include thermal spread, so that the Bernstein-ring instability is described by a more realistic electron distribution function, with which the stabilization by thermal spread associated with the ring distribution is demonstrated. The present findings imply that the excitation of Bernstein waves requires a sufficiently high perpendicular velocity gradient associated with the electron distribution function
Feedback stabilization initiative
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-06-01
Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.
Feedback stabilization initiative
International Nuclear Information System (INIS)
1997-06-01
Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes
Hydrodynamic and hydromagnetic stability
Chandrasekhar, S
1981-01-01
Dr. Chandrasekhar's book received high praise when it first appeared in 1961 as part of Oxford University Press' International Series of Monographs on Physics. Since then it has been reprinted numerous times in its expensive hardcover format. This first lower-priced, sturdy paperback edition will be welcomed by graduate physics students and scientists familiar with Dr. Chandrasekhar's work, particularly in light of the resurgence of interest in the Rayleigh-Bénard problem. This book presents a most lucid introduction to the Rayleigh-Bénard problem: it has also been applauded for its thorough, clear coverage of the theory of instabilities causing convection. Dr. Chandrasekhar considers most of the typical problems in hydromagnetic stability, with the exception of viscous shear flow; a specialized domain deserving a book unto itself. Contents include: Rotation; Stability of More General Flows; Bénard Problem; Gravitational Equilibrium and Instability; Stability of a Magnetic Field; Thermal Instability of a L...
Azimuthal magnetorotational instability with super-rotation
Rüdiger, G.; Schultz, M.; Gellert, M.; Stefani, F.
2018-02-01
It is demonstrated that the azimuthal magnetorotational instability (AMRI) also works with radially increasing rotation rates contrary to the standard magnetorotational instability for axial fields which requires negative shear. The stability against non-axisymmetric perturbations of a conducting Taylor-Couette flow with positive shear under the influence of a toroidal magnetic field is considered if the background field between the cylinders is current free. For small magnetic Prandtl number the curves of neutral stability converge in the (Hartmann number,Reynolds number) plane approximating the stability curve obtained in the inductionless limit . The numerical solutions for indicate the existence of a lower limit of the shear rate. For large the curves scale with the magnetic Reynolds number of the outer cylinder but the flow is always stable for magnetic Prandtl number unity as is typical for double-diffusive instabilities. We are particularly interested to know the minimum Hartmann number for neutral stability. For models with resting or almost resting inner cylinder and with perfectly conducting cylinder material the minimum Hartmann number occurs for a radius ratio of \\text{in}=0.9$ . The corresponding critical Reynolds numbers are smaller than 4$ .
Character of decay instability
International Nuclear Information System (INIS)
Polovin, R.V.; Demutskii, V.P.
1981-01-01
If the initial wave is unstable in the upper half plane Im ω>0 and there are no branch points of the quasiwave number, or if waves traveling in the same direction coalesce at a branch point, the instability is convective. On the other hand, if a branch point k(ω) does exist in the upper half-plane Im ω>0, and not all the waves that merge at this point travel in the same direction, the instability is absolute. A Green's function that describes the evolution of the perturbations of the initial wave in space and in time is constructed. The growth rates of the decay instability of the harmonics are determined. The produced waves are richer in harmonics than the initial waves. It is shown that the decay instability of an Alfven wave is absolute
Spondylolisthesis and Posterior Instability
International Nuclear Information System (INIS)
Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D.; Simons, P.; Kuchta, J.
2009-01-01
We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI
Spondylolisthesis and Posterior Instability
Energy Technology Data Exchange (ETDEWEB)
Niggemann, P.; Beyer, H.K.; Frey, H.; Grosskurth, D. (Privatpraxis fuer Upright MRT, Koeln (Germany)); Simons, P.; Kuchta, J. (Media Park Klinik, Koeln (Germany))
2009-04-15
We present the case of a patient with a spondylolisthesis of L5 on S1 due to spondylolysis at the level L5/S1. The vertebral slip was fixed and no anterior instability was found. Using functional magnetic resonance imaging (MRI) in an upright MRI scanner, posterior instability at the level of the spondylolytic defect of L5 was demonstrated. A structure, probably the hypertrophic ligament flava, arising from the spondylolytic defect was displaced toward the L5 nerve root, and a bilateral contact of the displaced structure with the L5 nerve root was shown in extension of the spine. To our knowledge, this is the first case described of posterior instability in patients with spondylolisthesis. The clinical implications of posterior instability are unknown; however, it is thought that this disorder is common and that it can only be diagnosed using upright MRI.
Accountability report - fiscal year 1997
Energy Technology Data Exchange (ETDEWEB)
NONE
1998-04-01
This document contains the US NRC`s accountability report for fiscal year 1997. Topics include uses of funds, financial condition, program performance, management accountability, and the audited financial statement.
Spending Disclosure - Fiscal Year 2012
Montgomery County of Maryland — The purpose of this Spending Disclosure Fiscal Year 12 dataset is to allow the public to search and view summary information on payments made to recipients (referred...
Genomic instability and radiation
Energy Technology Data Exchange (ETDEWEB)
Little, John B [Harvard School of Public Health, Boston, MA 02115 (United States)
2003-06-01
Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)
Genomic instability and radiation
International Nuclear Information System (INIS)
Little, John B
2003-01-01
Genomic instability is a hallmark of cancer cells, and is thought to be involved in the process of carcinogenesis. Indeed, a number of rare genetic disorders associated with a predisposition to cancer are characterised by genomic instability occurring in somatic cells. Of particular interest is the observation that transmissible instability can be induced in somatic cells from normal individuals by exposure to ionising radiation, leading to a persistent enhancement in the rate at which mutations and chromosomal aberrations arise in the progeny of the irradiated cells after many generations of replication. If such induced instability is involved in radiation carcinogenesis, it would imply that the initial carcinogenic event may not be a rare mutation occurring in a specific gene or set of genes. Rather, radiation may induce a process of instability in many cells in a population, enhancing the rate at which the multiple gene mutations necessary for the development of cancer may arise in a given cell lineage. Furthermore, radiation could act at any stage in the development of cancer by facilitating the accumulation of the remaining genetic events required to produce a fully malignant tumour. The experimental evidence for such induced instability is reviewed. (review)
The Practice of Fiscal Citizenship
Directory of Open Access Journals (Sweden)
Ana Maria da Costa Porto
2016-12-01
Full Text Available The citizen is not always aware of his tax rights and obligations, lacking awareness of the exercise of fiscal and tax citizenship. This article presents an analysis of the importance of the citizen to be informed about the embedded taxes when purchasing goods and providing services, as well as the way tax expenditures are made, so that he acquires an active and participatory citizenship for the purpose of achieving fiscal citizenship.
Monetary and Fiscal Policy Coordination
Hanif, Muhammad N.; Arby, Muhammad Farooq
2003-01-01
Macroeconomic policies are meant to achieve non-inflationary, stable growth. There are two major groups of policy instruments to achieve the purpose; one is related to monetary conditions and the other to fiscal conditions. Monetary instruments are employed by the central bank and fiscal instruments are employed by ministry of finance. The objectives and implications of policy measures taken by the two institutions often conflict with each other and thus call for policy coordination for effec...
Tidal instability in exoplanetary systems evolution
Directory of Open Access Journals (Sweden)
Le Gal P.
2011-02-01
Full Text Available A new element is proposed to play a role in the evolution of extrasolar planetary systems: the tidal (or elliptical instability. It comes from a parametric resonance and takes place in any rotating ﬂuid whose streamlines are (even slightly elliptically deformed. Based on theoretical, experimental and numerical works, we estimate the growth rate of the instability for hot-jupiter systems, when the rotation period of the star is known. We present the physical process, its application to stars, and preliminary results obtained on a few dozen systems, summarized in the form of a stability diagram. Most of the systems are trapped in the so-called "forbidden zone", where the instability cannot grow. In some systems, the tidal instability is able to grow, at short timescales compared to the system evolution. Implications are discussed in the framework of misaligned transiting systems, as the rotational axis of the star would be unstable in systems where this elliptical instability grows.
Adolescent patellar instability: current concepts review.
Clark, D; Metcalfe, A; Wogan, C; Mandalia, V; Eldridge, J
2017-02-01
Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis. Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis. This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients. Cite this article: Bone Joint J 2017;99-B:159-70. ©2017 The British Editorial Society of Bone & Joint Surgery.
Instability of flat space at finite temperature
International Nuclear Information System (INIS)
Gross, D.J.; Perry, M.J.; Yaffe, L.G.
1982-01-01
The instabilities of quantum gravity are investigated using the path-integral formulation of Einstein's theory. A brief review is given of the classical gravitational instabilities, as well as the stability of flat space. The Euclidean path-integral representation of the partition function is employed to discuss the instability of flat space at finite temperature. Semiclassical, or saddle-point, approximations are utilized. We show how the Jeans instability arises as a tachyon in the graviton propagator when small perturbations about hot flat space are considered. The effect due to the Schwarzschild instanton is studied. The small fluctuations about this instanton are analyzed and a negative mode is discovered. This produces, in the semiclassical approximation, an imaginary part of the free energy. This is interpreted as being due to the metastability of hot flat space to nucleate black holes. These then evolve by evaporation or by accretion of thermal gravitons, leading to the instability of hot flat space. The nucleation rate of black holes is calculated as a function of temperature
WAREHOUSE TRANSFERS AND FISCAL FRAUD
Directory of Open Access Journals (Sweden)
Stanciu Dorica
2015-07-01
Full Text Available The fraud and fiscal evasion phenomenon generate indisputable negative effects, which are felt directly on the level of fiscal receipts earnings, determining major distortions in the market’s functioning mechanism. If in the European Union, the contribution of the three large tax categories (direct tax, indirect and social contributions in forming revenue are relatively close, in Romania, fiscal and budget revenue are directly dependent on the indirect tax and duties, especially on VAT and various sales taxes. If there is reductions in the fiscal evasion as to what these taxes are concerned, the premises for creating budget resource needed to fund the economic growth are created. In judicial literature, tax evasion is considered as being the logic result of all defects and inadvertencies of an imperfect legislation, of broken application methods, as well as a lack of foreseeing and lack of skill on the law-maker’s side, with their excessive tax system is as guilty as those who contribute in creating it. Regardless of how this phenomenon is defined, fiscal evasion represents the lack of fulfillment by the taxpayer of his fiscal obligation. The field in which tax evasion acts is as widespread as the different taxes, manifesting especially in the direct and indirect taxes, influencing their efficiency.
Dynamic feedback for multi-mode plasma instabilities
International Nuclear Information System (INIS)
Sen, A.K.
1978-01-01
Constant feedback, which has been used exclusively, fails to stabilize more than one mode of a plasma instability. It is shown that a suitable dynamic or frequency-dependent feedback can stabilize all modes. Methods are developed in which such a feedback structure can be chosen in terms of its poles and zeros in relation to those of the plasma transfer function in the complex frequency plane. The synthesis procedure for such a feedback structure, in the form of an integrated electronic circuit is also discussed. As an example, a dynamic feedback for multi-mode stabilization of a collisional drift wave instability is developed in detail. (author)
Combustion instability modeling and analysis
Energy Technology Data Exchange (ETDEWEB)
Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States)] [and others
1995-10-01
It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. Clearly, the key to successful gas turbine development is based on understanding the effects of geometry and operating conditions on combustion instability, emissions (including UHC, CO and NO{sub x}) and performance. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors.
Damage instability and Earthquake nucleation
Ionescu, I. R.; Gomez, Q.; Campillo, M.; Jia, X.
2017-12-01
Earthquake nucleation (initiation) is usually associated to the loss of the stability of the geological structure under a slip-weakening friction acting on the fault. The key parameters involved in the stability of the fault are the stress drop, the critical slip distance but also the elastic stiffness of the surrounding materials (rocks). We want to explore here how the nucleation phenomena are correlated to the material softening during damage accumulation by dynamic and/or quasi-static processes. Since damage models are describing micro-cracks growth, which is generally an unstable phenomenon, it is natural to expect some loss of stability on the associated micro-mechanics based models. If the model accurately captures the material behavior, then this can be due to the unstable nature of the brittle material itself. We obtained stability criteria at the microscopic scale, which are related to a large class of damage models. We show that for a given continuous strain history the quasi-static or dynamic problems are instable or ill-posed (multiplicity of material responses) and whatever the selection rule is adopted, shocks (time discontinuities) will occur. We show that the quasi-static equilibria chosen by the "perfect delay convention" is always stable. These stability criteria are used to analyze how NIC (Non Interacting Crack) effective elasticity associated to "self similar growth" model work in some special configurations (one family of micro-cracks in mode I, II and III and in plane strain or plain stress). In each case we determine a critical crack density parameter and critical micro-crack radius (length) which distinguish between stable and unstable behaviors. This critical crack density depends only on the chosen configuration and on the Poisson ratio.
MHD instabilities in heliotron/torsatron
International Nuclear Information System (INIS)
Wakatani, Masahiro; Nakamura, Yuji; Ichiguchi, Katsuji
1992-01-01
Recent theoretical results on MHD instabilities in heliotron/torsatron are reviewed. By comparing the results with experimental data in Heliotron E, Heliotron DR and ATF, it is pointed out that resistive interchange modes are the most crucial instabilities, since the magnetic hill occupies a substantial region of the plasma column. Development of three-dimensional MHD equilibrium codes has made significant progress. By applying the local stability criteria shown by D 1 (ideal MHD mode) and D R (resistive MHD mode) to the equilibria given by the three-dimensional codes such as BETA and VMEC, stability thresholds for the low n ideal modes or the low n resistive modes may be estimated with resonable accuracy, where n is a toroidal mode number. (orig.)
Feedback control of coupled-bunch instabilities
International Nuclear Information System (INIS)
Fox, J.D.; Eisen, N.; Hindi, H.; Linscott, I.; Oxoby, G.; Sapozhnikov, L.; Serio, M.
1993-05-01
The next generation of synchrotron light sources and particle accelerators will require active feedback systems to control multi-bunch instabilities. Stabilizing hundreds or thousands of potentially unstable modes in these accelerator designs presents many technical challenges. Feedback systems to stabilize coupled-bunch instabilities may be understood in the frequency domain (mode-based feedback) or in the time domain (bunch-by-bunch feedback). In both approaches an external amplifier system is used to create damping fields that prevent coupled-bunch oscillations from growing without bound. The system requirements for transverse (betatron) and longitudinal (synchrotron) feedback are presented, and possible implementation options developed. Feedback system designs based on digital signal-processing techniques are described. Experimental results are shown from a synchrotron oscillation damper in the SSRL/SLAC storage ring SPEAR that uses digital signal-processing techniques
Triclade: influence of a sinuous secondary instability on the Richtmyer-Meshkov instabilities
International Nuclear Information System (INIS)
Boulet, M.; Griffond, J.
2004-01-01
Occurrence of a secondary instability developing after the Richtmyer-Meshkov (primary) instability is emphasized thanks to numerical simulations with the TRICLADE code. We are mainly considering 2D perturbations describes by trigonometric function cosine or [cosine]. However, the 3D case is also tackled. The sinuous secondary instability is characterized by the loss of the symmetries in the direction normal to the interface at its crests. It reduces the late time growing rate of the 'mushrooms' formed by the Richtmyer-Meshkov instability. Related simplified problems, like symmetrical Riemann problems or the Mallier-Maslowe array of counter-rotating vortices, allow us to perform 2D linear stability analysis. Thus, we show that the sinuous secondary instability is not a numerical artifact and that is comes from the continuous incompressible velocity field in the interface region. This instability implies temporal limitations for the validity of single mode simulations; therefore multimode simulations are necessary to study the ]ate-time behaviour of interfaces bitted by shocks. (authors)
Multibunch resistive wall instability damping with feedback
International Nuclear Information System (INIS)
Zhabitskij, V.M.; Korenev, I.L.; Yudin, L.A.
1992-01-01
The theory of multibunch transverse resistive wall instability damping with feedback is development. The system of coupling equations is obtained for description of bunched beam motion. The general solution and eigen frequencies are found. But for two bunches or multi bunches the tune splitting is found. The band of the tune splitting is calculated. The influence of the tune splitting on the damper system stability is discussed. 14 refs
Catastrophic Instability of Small Lovelock Black Holes
Takahashi, Tomohiro; Soda, Jiro
2010-01-01
We study the stability of static black holes in Lovelock theory which is a natural higher dimensional generalization of Einstein theory. We show that Lovelock black holes are stable under vector perturbations in all dimensions. However, we prove that small Lovelock black holes are unstable under tensor perturbations in even-dimensions and under scalar perturbations in odd-dimensions. Therefore, we can conclude that small Lovelock black holes are unstable in any dimensions. The instability is ...
CHANGES IN THE FISCAL CODE AND THEIR INFLUENCE ON THE ACTIVITY OF ROMANIAN COMPANIES
Directory of Open Access Journals (Sweden)
Gheorghe MOROŞAN
2016-09-01
Full Text Available Businesses, all over the world, want a stabile legislation. In the economic domain, all the companies need a clear fiscal code on a long period of time. Unfortunately, in the last ten years, the Romanian Fiscal Code has been amended several times. The old fiscal code is in force since 2003 and suffered throughout this period no less than 150 amendments. The unanimous opinion of the experts was that there was a clear need of a new code. The paper analyzes the changes brought by the Fiscal Code starting with 2016 and its implications on the activity of business operators and on the state budget for the next period of time. It seems that some of the changes will not have the desired effect on the state budget and, generally, on the economy.
Directory of Open Access Journals (Sweden)
Brianne A Beisner
2011-01-01
Full Text Available The persistence of biological systems requires evolved mechanisms which promote stability. Cohesive primate social groups are one example of stable biological systems, which persist in spite of regular conflict. We suggest that genetic relatedness and its associated kinship structure are a potential source of stability in primate social groups as kinship structure is an important organizing principle in many animal societies. We investigated the effect of average genetic relatedness per matrilineal family on the stability of matrilineal grooming and agonistic interactions in 48 matrilines from seven captive groups of rhesus macaques. Matrilines with low average genetic relatedness show increased family-level instability such as: more sub-grouping in their matrilineal groom network, more frequent fighting with kin, and higher rates of wounding. Family-level instability in multiple matrilines within a group is further associated with group-level instability such as increased wounding. Stability appears to arise from the presence of clear matrilineal structure in the rhesus macaque group hierarchy, which is derived from cohesion among kin in their affiliative and agonistic interactions with each other. We conclude that genetic relatedness and kinship structure are an important source of group stability in animal societies, particularly when dominance and/or affilative interactions are typically governed by kinship.
Jeans instability of self-gravitating magnetized strongly coupled plasma
International Nuclear Information System (INIS)
Prajapati, R P; Sharma, P K; Sanghvi, R K; Chhajlani, R K
2012-01-01
We investigate the Jeans instability of self-gravitating magnetized strongly coupled plasma. The equations of the problem are formulated using the generalized hydrodynamic model and a general dispersion relation is obtained using the normal mode analysis. This dispersion relation is discussed for transverse and longitudinal mode of propagations. The modified condition of Jeans instability is obtained for magnetized strongly coupled plasma. We find that strong coupling of plasma particles modify the fundamental criterion of Jeans gravitational instability. In transverse mode it is found that Jeans instability criterion gets modified due to the presence of magnetic field, shear viscosity and fluid viscosity but in longitudinal mode it is unaffected due to the presence of magnetic field. From the curves we found that all these parameters have stabilizing influence on the growth rate of Jeans instability.
Control of transversal instabilities in reaction-diffusion systems
Totz, Sonja; Löber, Jakob; Totz, Jan Frederik; Engel, Harald
2018-05-01
In two-dimensional reaction-diffusion systems, local curvature perturbations on traveling waves are typically damped out and vanish. However, if the inhibitor diffuses much faster than the activator, transversal instabilities can arise, leading from flat to folded, spatio-temporally modulated waves and to spreading spiral turbulence. Here, we propose a scheme to induce or inhibit these instabilities via a spatio-temporal feedback loop. In a piecewise-linear version of the FitzHugh–Nagumo model, transversal instabilities and spiral turbulence in the uncontrolled system are shown to be suppressed in the presence of control, thereby stabilizing plane wave propagation. Conversely, in numerical simulations with the modified Oregonator model for the photosensitive Belousov–Zhabotinsky reaction, which does not exhibit transversal instabilities on its own, we demonstrate the feasibility of inducing transversal instabilities and study the emerging wave patterns in a well-controlled manner.
Thresholds of a bunched beam longitudinal instability in proton synchrotrons
International Nuclear Information System (INIS)
Balbekov, V.I.; Ivanov, S.V.
1986-01-01
The formulas and graphs for calculating instability thresholds arising during the interaction of a bunched proton beam with narrow-band resonator are given. The instabilities of three types with oscillations of a definite multipolarity, oscillations of some bound multipoles and with microwave oscillations arising as a result of addition of a great number of multipoles. The analysis of the above data shows that the increase of oscillations nonlinearity is accompanied by the growth of instability threshold only in the zone of separated and weakly bound multipoles. The increase of spread of synchrotron frequencies reduces the zone separated multipoles owing to which the microwave bunch instability can be caused by more and more low-frequency resonators. In the microwave zone practically there is no stabilizing effect of synchrotron frequencies spread. The instability threshold of the bunched beam now - where exceeds the microwave level
Anomalous plasma transport due to electron temperature gradient instability
International Nuclear Information System (INIS)
Tokuda, Sinji; Ito, Hiroshi; Kamimura, Tetsuo.
1979-01-01
The collisionless drift wave instability driven by an electron temperature inhomogeneity (electron temperature gradient instability) and the enhanced transport processes associated with it are studied using a two-and-a-half dimensional particle simulation code. The simulation results show that quasilinear diffusion in phase space is an important mechanism for the saturation of the electron temperature gradient instability. Also, the instability yields particle fluxes toward the hot plasma regions. The heat conductivity of the electron temperature perpendicular to the magnetic field, T sub(e'), is not reduced by magnetic shear but remains high, whereas the heat conductivity of the parallel temperature, T sub(e''), is effectively reduced, and the instability stabilized. (author)
Anisotropy-Driven Instability in Intense Charged Particle Beams
Startsev, Edward; Qin, Hong
2005-01-01
In electrically neutral plasmas with strongly anisotropic distribution functions, free energy is available to drive different collective instabilities such as the electrostatic Harris instability and the transverse electromagnetic Weibel instability. Such anisotropies develop naturally in particle accelerators and may lead to a detoriation of beam quality. We have generalized the analysis of the classical Harris and Weibel instabilities to the case of a one-component intense charged particle beam with anisotropic temperature including the important effects of finite transverse geometry and beam space-charge. For a long costing beam, the delta-f particle-in-cell code BEST and the eighenmode code bEASt have been used to determine detailed 3D stability properties over a wide range of temperature anisotropy and beam intensity. A theoretical model is developed which describes the essential features of the linear stage of these instabilities. Both, the simulations and analytical theory, clearly show that moderately...
Secondary instability and transition in three-dimensional boundary layers
Energy Technology Data Exchange (ETDEWEB)
Stolte, A.; Bertolotti, F.P.; Koch, W. (Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Goettingen (Germany). Inst. fuer Stroemungsmechanik)
1999-01-01
Stationary and traveling crossflow modes are the most prominent disturbances in the highly accelerated three-dimensional flow near the leading edge of a swept wing. Near transition onset, secondary three-dimensional instabilities of high frequency can be observed in such flows. A model flow on the basis of a DLR swept plate experiment allows a detailed study of transition scenarios triggered by crossflow instabilities, since the favorable pressure gradient over the whole plate inhibits instabilities of Tollmien-Schlichting type. In order to shed some light upon the role of the high-frequency secondary instabilities, the saturation characteristics of crossflow vortices in this model flow are investigated using the parabolized stability equations. In contrast to nonlinear equilibrium solutions of steady crossflow vortices, the nonlinear Polarized Stability Equations (PSE) results yield different maximal disturbance amplitudes for different initial amplitudes. (orig./AKF)
Secondary instability and transition in three-dimensional boundary layers
Energy Technology Data Exchange (ETDEWEB)
Stolte, A.; Bertolotti, F.P.; Koch, W. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Goettingen (Germany). Inst. fuer Stroemungsmechanik
1999-12-01
Stationary and traveling crossflow modes are the most prominent disturbances in the highly accelerated three-dimensional flow near the leading edge of a swept wing. Near transition onset, secondary three-dimensional instabilities of high frequency can be observed in such flows. A model flow on the basis of a DLR swept plate experiment allows a detailed study of transition scenarios triggered by crossflow instabilities, since the favorable pressure gradient over the whole plate inhibits instabilities of Tollmien-Schlichting type. In order to shed some light upon the role of the high-frequency secondary instabilities, the saturation characteristics of crossflow vortices in this model flow are investigated using the parabolized stability equations. In contrast to nonlinear equilibrium solutions of steady crossflow vortices, the nonlinear Polarized Stability Equations (PSE) results yield different maximal disturbance amplitudes for different initial amplitudes. (orig./AKF)
On the ordinary mode instability for low beta plasmas
Energy Technology Data Exchange (ETDEWEB)
Hadi, F.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar (Pakistan); Bashir, M. F. [Department of Physics, G. C. University, Lahore (Pakistan); Salam Chair in Physics, G. C. University, Lahore (Pakistan); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2431 (United States); School of Space Research, Kyung Hee University, Yongin (Korea, Republic of); Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- and Astrophysik, Ruhr-Universität, Bochum (Germany)
2014-05-15
The purely growing ordinary (O) mode instability, first discussed by Davidson and Wu [Phys. Fluids 13, 1407 (1970)], has recently received renewed attention owing to its potential applicability to the solar wind plasma. In a series of papers, Ibscher, Schlickeiser, and their colleagues [Phys. Plasmas 19, 072116 (2012); ibid. 20, 012103 (2013); ibid. 20, 042121 (2013); ibid. 21, 022110 (2014)] revisited the O mode instability and extended it to the low-beta plasma regime by considering a counter-streaming bi-Maxwellian model. However, the O-mode instability is, thus, far discussed only on the basis of the marginal stability condition rather than actual numerical solutions of the dispersion relation. The present paper revisits the O-mode instability by considering the actual complex roots. The marginal stability condition as a function of the (electron) temperature anisotropy and beta naturally emerges in such a scheme.
Fiscal aspects of the European monetary integration
Directory of Open Access Journals (Sweden)
Golubović Srđan
2014-01-01
Full Text Available Along with the introduction of the euro as a single currency, importance of respecting the fiscal aspects which determine longevity of the monetary arrangement is recognized. For this reason, although underdeveloped, the EU fiscal system provides mechanisms to ensure fiscal discipline among member states. In addition to the fulfillment of the convergence criteria which is a precondition for joining the monetary union, they include no bailout clause and monetary financing prohibition. Sovereign debt that escalated in 2010 showed all the imperfections of these arrangements and pointed to the need for introduction of new and more effective fiscal rules. With fiscal system of the European Union as a starting point, the paper analyzes instruments defined by the fiscal system of the Union, which purpose is to ensure fiscal discipline of the European Monetary Union member states. Last part of the paper analyze new fiscal rules introduced as a response to the debt crisis in the Eurozone.
Budget estimates, fiscal years 1994--1995
International Nuclear Information System (INIS)
1993-04-01
This report contains the fiscal year budget justification to Congress. The budget provides estimates for salaries and expenses and for the Office of the Inspector General for fiscal years 1994 and 1995
Financial fragility and the fiscal multiplier
van Wijnbergen, S.; van der Kwaak, C.
2013-01-01
We investigate the effectiveness of `Keynesian' fiscal stimuli when government deficits and debt rollovers are (possibly partially) financed by balance sheet constrained financial intermediaries. Because financial intermediaries operate under a leverage constraint, deficit financing of fiscal
SUSTAINABILITY OF FISCAL POLICY. CASE OF ROMANIA*
Ionuţ-Cătălin Croitoru
2012-01-01
The Sustainability of fiscal policy is one of the key concerns of each state, especially in periods of macroeconomic imbalance. This study aims to explore the concept of sustainability of Romanian’s fiscal policy. The analysis starts from the definition of sustainability of fiscal policy and its assessment methods. The work is based on the idea that a sustainable fiscal policy ensure sufficient financial resources for long-term to reduce public debt to GDP weighting and provide permits for gr...
Can Fiscal Policy Stimulus Boost Economic Recovery?
Agnello, L.; Sousa, R.
2011-01-01
We assess the role played by fiscal policy in explaining the dynamics of asset markets. Using a panel of ten industrialized countries, we show that a positive fiscal shock has a negative impact in both stock and housing prices. However, while stock prices immediately adjust to the shock and the effect of fiscal policy is temporary, housing prices gradually and persistently fall. Consequently, the attempts of fiscal policy to mitigate stock price developments (e.g. via taxes on capital gains) ...
Taxation, Fiscal Deficit and Inflation in Pakistan
Ghulam Rasool Madni
2014-01-01
Fiscal policy has more controversial debate regarding its effectiveness on different macroeconomic activities of an economy. Taxation and government expenditure are two main instruments of fiscal policy. This paper is aimed to analyze and update the effects of different instruments of fiscal policy on inflation in Pakistan economy. The data time span for this study is 1979-2013. The impact of fiscal policy on inflation is analyzed by utilizing the Bounds testing procedure and ARDL approach of...
Comparative fiscal illusion: A fiscal illusion index for the European Union
Dell'Anno, Roberto; Dollery, Brian
2012-01-01
This paper provides an empirical analysis of fiscal illusion by estimating an index of fiscal illusion for 28 European countries over the period 1995–2008 employing a structural equation approach. Using MIMIC models, the paper investigates the main indicators of fiscal illusion and develops an index of fiscal illusion. It concludes that the chief deterninants for the deployment of fiscal illusion strategies are the share of self-employment on total employment, the educational level of citizen...
Theory of the rippling instability in toroidal devices
International Nuclear Information System (INIS)
Rogister, A.
1985-04-01
The theory of the rippling instability is developed for axisymmetric toroidal plasmas including ion viscosity and parallel electron heat conduction, but assuming that the growth rate is small compared to the wave angular frequency. Parallel electron heat conduction is stabilizing but ion viscosity broadens the instability domain. Under certain conditions, an important top-bottom asymmetry of the density fluctuation spectrum may arise. (orig./GG)
Instability in relativistic mean-field theories of nuclear matter
International Nuclear Information System (INIS)
Friman, B.L.; Henning, P.A.
1988-01-01
We investigate the stability of the nuclear matter ground state with respect to small-perturbations of the meson fields in relativistic mean-field theories. The popular σ-ω model is shown to have an instability at about twice the nuclear density, which gives rise to a new ground state with periodic spin alignment. Taking into account the contributions of the Dirac sea properly, this instability vanishes. Consequences for relativistic heavy-ion-collisions are discussed briefly. (orig.)
Instability in relativistic mean-field theories of nuclear matter
International Nuclear Information System (INIS)
Friman, B.L.; Henning, P.A.
1988-01-01
We investigate the stability of the nuclear matter ground state with respect to small perturbations of the meson fields in relativistic mean-field theories. The popular σ-ω model is shown to have an instability at about twice the nuclear density, which gives rise to a new ground state with periodic spin alignment. Taking into account the contributions of the Dirac sea properly, this instability vanishes. Consequences for relativistic heavy-ion collisions are discussed briefly. (orig.)
Modulational instability and nonlocality management in coupled NLS systems
International Nuclear Information System (INIS)
Doktorov, Evgeny V; Molchan, Maxim A
2007-01-01
The modulational instability of two interacting waves in a nonlocal Kerr-type medium is considered analytically and numerically. For a generic choice of wave amplitudes, we give a complete description of stable/unstable regimes for zero group-velocity mismatch. It is shown that nonlocality suppresses considerably the growth rate and bandwidth of instability. For nonzero group-velocity mismatch we perform a geometrical analysis of a nonlocality management which can provide stability of waves otherwise unstable in a local medium
Fingerprints of dynamical instabilities
International Nuclear Information System (INIS)
Chomaz, Ph.; Colonna, M.; Guarnera, A.
1993-01-01
It is explained why any reduced descriptions, such as mean field approximation, are stochastic in nature. It is shown that the introduction of this stochastic dynamics leads to a predictive theory in a statistical sens whatever the individual trajectories are characterized by the occurrence of bifurcations, instabilities or phase transitions. Concerning nuclear matter, the spinodal instability is discussed. In such a critical situation, the possibility to replace the stochastic part of the collision integral in the Boltzmann-Langevin model by the numerical noise associated with the finite number of test particles in ordinary BUU treatment is studied. It is shown that the fingerprints of these instabilities are kept during the evolution because of the relatively long recombination time compared with the typical time scales imposed by the Coulomb repulsion and the possible collective expansion. (author) 5 refs., 12 figs
Instability and star evolution
International Nuclear Information System (INIS)
Mirzoyan, L.V.
1981-01-01
The observational data are discussed which testify that the phenomena of dynamical instability of stars and stellar systems are definite manifestations of their evolution. The study of these phenomena has shown that the instability is a regular phase of stellar evolution. It has resulted in the recognition of the most important regularities of the process of star formation concerning its nature. This became possible due to the discovery in 1947 of stellar associations in our Galaxy. The results of the study of the dynamical instability of stellar associations contradict the predictions of classical hypothesis of stellar condensation. These data supplied a basis for a new hypothesis on the formation of stars and nebulae by the decay of superdense protostars [ru
Rolie-Poly fluid flowing through constrictions: Two distinct instabilities
Reis, T.; Wilson, H.J.
2013-01-01
Elastic instabilities of entangled polymer melts are common in industrial processes but the physics responsible is not well understood. We present a numerical linear stability study of a molecular based constitutive model which grants us physical insight into the underlying mechanics involved. Two constriction flows are considered - one shear dominated, the other extension dominated - and two distinct instabilities are found. The influence of the molecular structure and the behaviour of the polymer dynamics are investigated and in both cases chain relaxation and orientation play a crucial role. This suggests a molecular-based physical interpretation of the underlying mechanisms responsible for flow instabilities. © 2013 Elsevier B.V.
Numerical studies of edge localized instabilities in tokamaks
International Nuclear Information System (INIS)
Wilson, H.R.; Snyder, P.B.; Huysmans, G.T.A.; Miller, R.L.
2002-01-01
A new computational tool, edge localized instabilities in tokamaks equilibria (ELITE), has been developed to help our understanding of short wavelength instabilities close to the edge of tokamak plasmas. Such instabilities may be responsible for the edge localized modes observed in high confinement H-mode regimes, which are a serious concern for next step tokamaks because of the high transient power loads which they can impose on divertor target plates. ELITE uses physical insight gained from analytic studies of peeling and ballooning modes to provide an efficient way of calculating the edge ideal magnetohydrodynamic stability properties of tokamaks. This paper describes the theoretical formalism which forms the basis for the code
Feedback to suppress beam instabilities in future proton rings
International Nuclear Information System (INIS)
Lambertson, G.R.
1985-05-01
Criteria for the design of feedback systems to suppress coherent beam instabilities are presented. These address starting amplitudes, diffusion from noise during damping or long storage, and choice of kicker. As a model for future accelerators, specifications of the proposed 20 TeV SSC are used to calculate parameters of systems to control expected instabilities. A scenario and hardware to stabilize the transverse mode-coupling instability is examined. The scale of the systems is large but not out of scale with the large ring. 9 refs., 4 tabs
Rolie-Poly fluid flowing through constrictions: Two distinct instabilities
Reis, T.
2013-05-01
Elastic instabilities of entangled polymer melts are common in industrial processes but the physics responsible is not well understood. We present a numerical linear stability study of a molecular based constitutive model which grants us physical insight into the underlying mechanics involved. Two constriction flows are considered - one shear dominated, the other extension dominated - and two distinct instabilities are found. The influence of the molecular structure and the behaviour of the polymer dynamics are investigated and in both cases chain relaxation and orientation play a crucial role. This suggests a molecular-based physical interpretation of the underlying mechanisms responsible for flow instabilities. © 2013 Elsevier B.V.
The Economic Causes and Consequences of Social Instability in China
John Knight
2012-01-01
Social instability is a concept that economists rarely analyse, and yet it can lurk behind much economic policy-making. Chinaâ€™s leadership has often publicly expressed its concerns to avoid â€˜social instabilityâ€™. It is viewed as a threat both to the political order and to the continued rapid growth of the economy. This threat to growth in turn endangers the maintenance of social stability. This paper examines the likely economic determinants of social instability, using both surveys and ...
45 CFR 402.21 - Fiscal control.
2010-10-01
... 45 Public Welfare 2 2010-10-01 2010-10-01 false Fiscal control. 402.21 Section 402.21 Public Welfare Regulations Relating to Public Welfare OFFICE OF REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN... Administration of Grants § 402.21 Fiscal control. (a) Fiscal control and accounting procedures must be sufficient...
34 CFR 303.125 - Fiscal control.
2010-07-01
... 34 Education 2 2010-07-01 2010-07-01 false Fiscal control. 303.125 Section 303.125 Education... DISABILITIES State Application for a Grant Statement of Assurances § 303.125 Fiscal control. The statement must provide assurance satisfactory to the Secretary that such fiscal control and fund accounting procedures...
Energy Technology Data Exchange (ETDEWEB)
NONE
1990-03-01
With an objective of establishing the fundamental technologies related to photo reactive materials that can be used for ultra-high density recording, high-resolution indication, and photoswitches by controlling structures and association status of molecules by using actions of light, research and development has been performed. This paper summarizes the achievements in fiscal 1989. In the research of synthesis and evaluation of PHB materials, a possibility was verified to form holes at temperatures higher than the liquid nitrogen temperature on all the materials in which six kinds of ionic porphin derivatives were dispersed into polyvinyl alcohol. Stability of holes in the tetra-alkyl pyridinium porhpn/polymer system was evaluated, the hole half-width was measured accurately by using ring die laser, and the hole forming characteristics were evaluated by means of high-power density and brief laser light irradiation. In search of new guests, a two-photon absorption spectrum measuring instrument was assembled to measure samples having zinc tetra-phenylporphyrin derivative as the guest. In addition, hole formation was discovered in samples having indomethylene based coloring matter as the guest. (NEDO)
DEFF Research Database (Denmark)
Langie, Sabine A S; Koppen, Gudrun; Desaulniers, Daniel
2015-01-01
function, chromosome segregation, telomere length). The purpose of this review is to describe the crucial aspects of genome instability, to outline the ways in which environmental chemicals can affect this cancer hallmark and to identify candidate chemicals for further study. The overall aim is to make......Genome instability is a prerequisite for the development of cancer. It occurs when genome maintenance systems fail to safeguard the genome's integrity, whether as a consequence of inherited defects or induced via exposure to environmental agents (chemicals, biological agents and radiation). Thus...
Instabilities and nonequilibrium structures
International Nuclear Information System (INIS)
Tirapegui, E.; Villarroel, D.
1987-01-01
Physical systems can be studied both near to and far from equilibrium where instabilities appear. The behaviour in these two regions is reviewed in this book, from both the theoretical and application points of view. The influence of noise in these situations is an essential feature which cannot be ignored. It is therefore discussed using phenomenological and theoretical approaches for the numerous problems which still remain in the field. This volume should appeal to mathematicians and physicists interested in the areas of instability, bifurcation theory, dynamical systems, pattern formation, nonequilibrium structures and statistical mechanics. (Auth.)
RINGED ACCRETION DISKS: INSTABILITIES
Energy Technology Data Exchange (ETDEWEB)
Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)
2016-04-01
We analyze the possibility that several instability points may be formed, due to the Paczyński mechanism of violation of mechanical equilibrium, in the orbiting matter around a supermassive Kerr black hole. We consider a recently proposed model of a ringed accretion disk, made up by several tori (rings) that can be corotating or counter-rotating relative to the Kerr attractor due to the history of the accretion process. Each torus is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. We prove that the number of the instability points is generally limited and depends on the dimensionless spin of the rotating attractor.
The Interaction of Monetary and Fiscal Policy in the Countries of the Visegrad Group
Directory of Open Access Journals (Sweden)
Jan Janků
2014-01-01
Full Text Available Coordination of or at least absence of conflict between monetary and fiscal policies are key to the successful implementation of economic policy. The article aims to use reaction functions to assess whether the monetary and fiscal policies in the countries of the Visegrad Group are in coordination or in conflict and which variables influence their decisions. The central bank is the representative of monetary policy, which has interest rates as its instrument, and the government as the representative of the fiscal policy which has change revenue or spending as a share of GDP as instrument. To obtain the results, multivariate regression analysis is used. The research period is based on quarterly observations from first quarter of 2000 to the fourth quarter of 2012. Stabilizing role of monetary policy and in some countries also partially stabilizing role of fiscal policy has been found. Another result was that in the case of the Czech Republic, Slovakia and Poland, monetary policy appears to play the dominant role, whereas fiscal policy plays dominant role in Hungary. In the case of Slovakia, some different results may be due to Slovakia’s participation in ERM II, which led to the monetary policy, in addition to maintaining price stability, also aiming to maintain a fixed exchange rate and the subsequent entry of Slovakia into the Eurozone and the de facto loss of autonomous monetary policy.
Structural Stability and Vibration
DEFF Research Database (Denmark)
Wiggers, Sine Leergaard; Pedersen, Pauli
This book offers an integrated introduction to the topic of stability and vibration. Strikingly, it describes stability as a function of boundary conditions and eigenfrequency as a function of both boundary conditions and column force. Based on a post graduate course held by the author at the Uni...... and their derivation, thus stimulating them to write interactive and dynamic programs to analyze instability and vibrational modes....
Buneman instability and Pierce instability in a collisionless bounded plasma
International Nuclear Information System (INIS)
Iizuka, Satoru; Saeki, Koichi; Sato, Noriyoshi; Hatta, Yoshisuke
1983-01-01
A systematic experiment is performed on the Buneman instability and the Pierce instability in a bounded plasma consisting of beam electrons and stationary ions. Current fluctuations are confirmed to be induced by the Buneman instability. On the other hand, the Pierce instability gives rise to a current limitation. The phenomena are well explained by Mikhailovskii's theory taking account of ion motion in a bounded plasma. (author)
Fiscal system analysis - contractual systems
International Nuclear Information System (INIS)
Kaiser, M.J.
2006-01-01
Production sharing contracts are one of the most popular forms of contractual system used in petroleum agreements around the world, but the manner in which the fiscal terms and contract parameters impact system measures is complicated and not well understood. The purpose of this paper is to quantify the influence of private and market uncertainty in contractual fiscal systems. A meta-modelling approach is employed that couples the results of a simulation model with regression analysis to construct numerical functionals that quantify the fiscal regime. Relationships are derived that specify how the present value, rate of return, and take statistics vary as a function of the system parameters. The deepwater Girassol field development in Angola is taken as a case study. (author)
Nam, Seung-Min; Kim, Kyoung; Lee, Do Youn
2018-01-01
[Purpose] This study examined the effects of visual feedback balance training on the balance and ankle instability in adult men with functional ankle instability. [Subjects and Methods] Twenty eight adults with functional ankle instability, divided randomly into an experimental group, which performed visual feedback balance training for 20 minutes and ankle joint exercises for 10 minutes, and a control group, which performed ankle joint exercise for 30 minutes. Exercises were completed three times a week for 8 weeks. Bio rescue was used for balance ability. It measured limit of stability at one minute. For ankle instability was measured using Cumberland ankle instability tool (CAIT). This measure was performed before and after the experiments in each group. [Results] The experimental group had significant increase in the Limit of Stability and CAIT score. The control group had significant increase in CAIT score. While the Limit of Stability increased without significance. [Conclusion] In conclusion, visual feedback balance training can be recommended as a treatment method for patients with functional ankle instability.
The SOL width and the MHD interchange instability in tokamaks
Energy Technology Data Exchange (ETDEWEB)
Kerner, W [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Pogutse, O [Kurchatov institute, Moscow (Russian Federation)
1994-07-01
Instabilities in the SOL plasma can strongly influence the SOL plasma behaviour and in particular the SOL width. The SOL stability analysis shows that there exists a critical ratio of the thermal energy and the magnetic energy. If the SOL beta is greater than this critical value, the magnetic field cannot prevent the plasma displacement and a strong MHD instability in the SOL occurs. In the opposite case only slower resistive instabilities can develop. A theoretical investigation of the SOL plasma stability is presented for JET single-null and double-null divertor configurations. The dependence of the stability threshold on the SOL beta and on the sheath resistance is established. Applying a simple mixing length argument gives the scaling of the SOL width. 5 refs., 2 figs.
DEFF Research Database (Denmark)
Olsen, Bo Sanderhoff; Henriksen, M G; Søjbjerg, Jens Ole
1994-01-01
The effect of simultaneous ulnar and radial collateral ligament division on the kinematics of the elbow joint is studied in a cadaveric model. Severance of the anterior part of the ulnar collateral ligament and the annular ligament led to significant elbow joint instability in valgus and varus...
Structural and Material Instability
DEFF Research Database (Denmark)
Cifuentes, Gustavo Cifuentes
This work is a small contribution to the general problem of structural and material instability. In this work, the main subject is the analysis of cracking and failure of structural elements made from quasi-brittle materials like concrete. The analysis is made using the finite element method. Three...
Agricultural Markets Instability
Garrido, A.; Brümmer, B.; M'Barek, R.; Gielen-Meuwissen, M.P.M.; Morales-Opazo, C.
2016-01-01
Since the financial and food price crises of 2007, market instability has been a topic of major concern to agricultural economists and policy professionals. This volume provides an overview of the key issues surrounding food prices volatility, focusing primarily on drivers, long-term implications of
Comment on critical instability
International Nuclear Information System (INIS)
King, S.F.; Suzuki, Mahiko
1992-01-01
We discuss the problem of the mass splitting between top and bottom quarks, within the context of Nambu-Jona-Lasinio type models involving top and bottom quark condensates. We interpret the phenomenon of 'critical instability' recently proposed to account for such a mass splitting as the fine-tuning of two vacuum expectation values in a composite two-Higgs doublet model. (orig.)
Linear instability and nonlinear motion of rotating plasma
International Nuclear Information System (INIS)
Liu, J.
1985-01-01
Two coupled nonlinear equations describing the flute dynamics of the magnetically confined low-β collisionless rotating plasma are derived. The linear instability and nonlinear dynamics of the rotating column are analyzed theoretically. In the linear stability analysis, a new sufficient condition of stability is obtained. From the exact solution of eigenvalue equation for Gaussian density profile and uniform rotation of the plasma, the stability of the system strongly depends on the direction of plasma rotation, FLR effect and the location of the conducting wall. An analytic expression showing the finite wall effect on different normal modes is obtained and it explains the different behavior of (1,0) normal mode from other modes. The sheared rotation driven instability is investigated by using three model equilibrium profiles, and the analytic expressions of eigenvalues which includes the wall effect are obtained. The analogy between shear rotation driven instability and the instability driven by sheared plane parallel flow in the inviscid fluid is analyzed. Applying the linear analysis to the central cell of tandem mirror system, the trapped particle instability with only passing electronics is analyzed. For uniform rotation and Gaussian density profile, an analytic expression that determines the stability boundary is found. The nonlinear analysis shows that the nonlinear equations have a solitary vortex solution which is very similar to the vortex solution of nonlinear Rossby wave equation
The Effects of growing Indian military potential on South Asian stability
2017-06-09
POTENTIAL ON SOUTH ASIAN STABILITY , by Major Hashim I. Bajwa, 116 pages. India is emerging as an economic powerhouse and its national power is on...Afghanistan, Nepal, and Myanmar due to the political and economic instability in these countries. He advocates an assertive politico-military outlook for... instability in South Asia to Glen Snyder’s “ stability / instability paradox.” He argues that the “ stability / instability paradox” is still relevant in
Summary of the electric power supply program for fiscal 1981
International Nuclear Information System (INIS)
Shimada, Minoru
1981-01-01
The plans of electric power supply for fiscal 1981 (from April, 1981, to March, 1982) by the power companies were formulated and submitted to the Ministry of International Trade and Industry. Along with the current up trend of economic activities, the demands of electric power will be on the increase. A summer peak of power consumption may rise all the more due to the increase in room-cooling units. On the other hand, the problem of petroleum is unsettled. Under the situation, the principal considerations behind the formulation of the plans are the effective utilization of other energy resources than oil and the suppression of oil-burning power generation, the economical usage of all power generation facilities and stabilized demand and supply, and the promotion of wide-area operation. The situation in fiscal 1981, power demands, power source facilities demand and supply balance, and the interchange of power among power companies are described. (J.P.N.)
Mix and hydrodynamic instabilities on NIF
Smalyuk, V. A.; Robey, H. F.; Casey, D. T.; Clark, D. S.; Döppner, T.; Haan, S. W.; Hammel, B. A.; MacPhee, A. G.; Martinez, D.; Milovich, J. L.; Peterson, J. L.; Pickworth, L.; Pino, J. E.; Raman, K.; Tipton, R.; Weber, C. R.; Baker, K. L.; Bachmann, B.; Berzak Hopkins, L. F.; Bond, E.; Caggiano, J. A.; Callahan, D. A.; Celliers, P. M.; Cerjan, C.; Dixit, S. N.; Edwards, M. J.; Felker, S.; Field, J. E.; Fittinghoff, D. N.; Gharibyan, N.; Grim, G. P.; Hamza, A. V.; Hatarik, R.; Hohenberger, M.; Hsing, W. W.; Hurricane, O. A.; Jancaitis, K. S.; Jones, O. S.; Khan, S.; Kroll, J. J.; Lafortune, K. N.; Landen, O. L.; Ma, T.; MacGowan, B. J.; Masse, L.; Moore, A. S.; Nagel, S. R.; Nikroo, A.; Pak, A.; Patel, P. K.; Remington, B. A.; Sayre, D. B.; Spears, B. K.; Stadermann, M.; Tommasini, R.; Widmayer, C. C.; Yeamans, C. B.; Crippen, J.; Farrell, M.; Giraldez, E.; Rice, N.; Wilde, C. H.; Volegov, P. L.; Gatu Johnson, M.
2017-06-01
Several new platforms have been developed to experimentally measure hydrodynamic instabilities in all phases of indirect-drive, inertial confinement fusion implosions on National Ignition Facility. At the ablation front, instability growth of pre-imposed modulations was measured with a face-on, x-ray radiography platform in the linear regime using the Hydrodynamic Growth Radiography (HGR) platform. Modulation growth of "native roughness" modulations and engineering features (fill tubes and capsule support membranes) were measured in conditions relevant to layered DT implosions. A new experimental platform was developed to measure instability growth at the ablator-ice interface. In the deceleration phase of implosions, several experimental platforms were developed to measure both low-mode asymmetries and high-mode perturbations near peak compression with x-ray and nuclear techniques. In one innovative technique, the self-emission from the hot spot was enhanced with argon dopant to "self-backlight" the shell in-flight. To stabilize instability growth, new "adiabat-shaping" techniques were developed using the HGR platform and applied in layered DT implosions.
Dynamical instability of hot and compressed nuclei
International Nuclear Information System (INIS)
Ngo, C.; Leray, S.; Spina, M.E.; Ngo, H.
1989-01-01
The dynamical evolution of a hot and compressed nucleus is described by means of an extended liquid-drop model. Using only the continuity equation and the energy conservation we show that the system expands after a while. The possible global instabilities of the drop are studied by applying the general conditions of stability of dynamical systems. We find that the nucleus is unstable if it can reach a low density configuration (≅0.07 nucleon/fm 3 ). Such a configuration is obtained if the initial compression of the nucleus is large enough. It is shown that the thermal excitation energy has much less influence than the compressional energy. These instability conditions are in good agreement with those obtained previously within the framework of lattice percolation and the same model for the dynamical expansion. Since local instabilities may also very likely be present, we propose to study them using a restructured aggregation model. They lead to a multifragmentation of the system, a mechanism which is known experimentally to exist. We find that local instabilities occur at smaller (but very close) density values than global ones. A moment analysis of the calculated multifragmentation events allows to extract a critical exponent in excellent agreement with the one deduced experimentally from Au-induced reactions. (orig.)
Curvature-Induced Instabilities of Shells
Pezzulla, Matteo; Stoop, Norbert; Steranka, Mark P.; Bade, Abdikhalaq J.; Holmes, Douglas P.
2018-01-01
Induced by proteins within the cell membrane or by differential growth, heating, or swelling, spontaneous curvatures can drastically affect the morphology of thin bodies and induce mechanical instabilities. Yet, the interaction of spontaneous curvature and geometric frustration in curved shells remains poorly understood. Via a combination of precision experiments on elastomeric spherical shells, simulations, and theory, we show how a spontaneous curvature induces a rotational symmetry-breaking buckling as well as a snapping instability reminiscent of the Venus fly trap closure mechanism. The instabilities, and their dependence on geometry, are rationalized by reducing the spontaneous curvature to an effective mechanical load. This formulation reveals a combined pressurelike term in the bulk and a torquelike term in the boundary, allowing scaling predictions for the instabilities that are in excellent agreement with experiments and simulations. Moreover, the effective pressure analogy suggests a curvature-induced subcritical buckling in closed shells. We determine the critical buckling curvature via a linear stability analysis that accounts for the combination of residual membrane and bending stresses. The prominent role of geometry in our findings suggests the applicability of the results over a wide range of scales.
Electroacoustic control of Rijke tube instability
Zhang, Yumin; Huang, Lixi
2017-11-01
Unsteady heat release coupled with pressure fluctuation triggers the thermoacoustic instability which may damage a combustion chamber severely. This study demonstrates an electroacoustic control approach of suppressing the thermoacoustic instability in a Rijke tube by altering the wall boundary condition. An electrically shunted loudspeaker driver device is connected as a side-branch to the main tube via a small aperture. Tests in an impedance tube show that this device has sound absorption coefficient up to 40% under normal incidence from 100 Hz to 400 Hz, namely over two octaves. Experimental result demonstrates that such a broadband acoustic performance can effectively eliminate the Rijke-tube instability from 94 Hz to 378 Hz (when the tube length varies from 1.8 m to 0.9 m, the first mode frequency for the former is 94 Hz and the second mode frequency for the latter is 378 Hz). Theoretical investigation reveals that the devices act as a damper draining out sound energy through a tiny hole to eliminate the instability. Finally, it is also estimated based on the experimental data that small amount of sound energy is actually absorbed when the system undergoes a transition from the unstable to stable state if the contrpaol is activated. When the system is actually stabilized, no sound is radiated so no sound energy needs to be absorbed by the control device.
Tracking Code for Microwave Instability
International Nuclear Information System (INIS)
Heifets, S.; SLAC
2006-01-01
To study microwave instability the tracking code is developed. For bench marking, results are compared with Oide-Yokoya results [1] for broad-band Q = 1 impedance. Results hint to two possible mechanisms determining the threshold of instability
Instabilities in thin tunnel junctions
International Nuclear Information System (INIS)
Konkin, M.K.; Adler, J.G.
1978-01-01
Tunnel junctions prepared for inelastic electron tunneling spectroscopy are often plagued by instabilities in the 0-500-meV range. This paper relates the bias at which the instability occurs to the barrier thickness
Stability of Randomly Switched Diffusions
DEFF Research Database (Denmark)
Schiøler, Henrik; Leth, John-Josef; Gholami, Mehdi
2012-01-01
This paper provides a sufficient criterion for ε-moment stability (boundedness) and ergodicity for a class of systems comprising a finite set of diffusions among which switching is governed by a continuous time Markov chain. Stability/instability properties for each separate subsystem are assumed...
Scaling and uncertainty in BWR instability problems
International Nuclear Information System (INIS)
Di Auria, F.; Pellicoro, V.
1995-01-01
This paper deals with a critical review of activities, performed at the DCMN of Pisa University, in relation to the thermo-hydraulic oscillations in two-phase systems. Stability analyses, including model development and achievement of experimental data, are generally performed for BWRs in order to achieve the following objectives: to reach a common understanding in relation to the predictive capabilities of system codes and to the influence of various parameters on the instability; to establish a data base for the qualification of the analytical tools already or becoming available; to set-up qualified tools (code/models + nodalization + user assumption) suitable for predicting the unstable behaviour of the nuclear plants of interest (current BWR, SBWR, ABWR and RBMK). These considerations have been the basis for the following researches: 1) proposal of the Boiling Instability Program (BIP) (1) 2) evaluation of stability tests in PIPER-ONE apparatus (2) 3) coupled thermal-hydraulic and neutronic instabilities in the LaSalle-2 BWR plant (3) 4) participation to the NEA-OECD BWR Benchmark (4) The RELAP/MOD2 and RELAP5/MOD3 codes have been used. (author)
Nonlinear evolution of MHD instabilities
International Nuclear Information System (INIS)
Bateman, G.; Hicks, H.R.; Wooten, J.W.; Dory, R.A.
1975-01-01
A 3-D nonlinear MHD computer code was used to study the time evolution of internal instabilities. Velocity vortex cells are observed to persist into the nonlinear evolution. Pressure and density profiles convect around these cells for a weak localized instability, or convect into the wall for a strong instability. (U.S.)
Neuromuscular control and ankle instability.
Gutierrez, Gregory M; Kaminski, Thomas W; Douex, Al T
2009-04-01
Lateral ankle sprains (LAS) are common injuries in athletics and daily activity. Although most are resolved with conservative treatment, others develop chronic ankle instability (AI)-a condition associated with persistent pain, weakness, and instability-both mechanical (such as ligamentous laxity) and functional (neuromuscular impairment with or without mechanical laxity). The predominant theory in AI is one of articular deafferentation from the injury, affecting closed-loop (feedback/reflexive) neuromuscular control, but recent research has called that theory into question. A considerable amount of attention has been directed toward understanding the underlying causes of this pathology; however, little is known concerning the neuromuscular mechanisms behind the development of AI. The purpose of this review is to summarize the available literature on neuromuscular control in uninjured individuals and individuals with AI. Based on available research and reasonable speculation, it seems that open-loop (feedforward/anticipatory) neuromuscular control may be more important for the maintenance of dynamic joint stability than closed-loop control systems that rely primarily on proprioception. Therefore, incorporating perturbation activities into patient rehabilitation schemes may be of some benefit in enhancing these open-loop control mechanisms. Despite the amount of research conducted in this area, analysis of individuals with AI during dynamic conditions is limited. Future work should aim to evaluate dynamic perturbations in individuals with AI, as well as subjects who have a history of at least one LAS and never experienced recurrent symptoms. These potential findings may help elucidate some compensatory mechanisms, or more appropriate neuromuscular control strategies after an LAS event, thus laying the groundwork for future intervention studies that can attempt to reduce the incidence and severity of acute and chronic lateral ankle injury.
Instability in Thoracolumbar Trauma: Is a New Definition Warranted?
Abbasi Fard, Salman; Skoch, Jesse; Avila, Mauricio J; Patel, Apar S; Sattarov, Kamran V; Walter, Christina M; Baaj, Ali A
2017-10-01
Review of the articles. The objective of this study was to review all articles related to spinal instability to determine a consensus statement for a contemporary, practical definition applicable to thoracolumbar injuries. Traumatic fractures of the thoracolumbar spine are common. These injuries can result in neurological deficits, disability, deformity, pain, and represent a great economic burden to society. The determination of spinal instability is an important task for spine surgeons, as treatment strategies rely heavily on this assessment. However, a clinically applicable definition of spinal stability remains elusive. A review of the Medline database between 1930 and 2014 was performed limited to papers in English. Spinal instability, thoracolumbar, and spinal stability were used as search terms. Case reports were excluded. We reviewed listed references from pertinent search results and located relevant manuscripts from these lists as well. The search produced a total of 694 published articles. Twenty-five articles were eligible after abstract screening and underwent full review. A definition for spinal instability was described in only 4 of them. Definitions were primarily based on biomechanical and classification studies. No definitive parameters were outlined to define stability. Thirty-six years after White and Panjabi's original definition of instability, and many classification schemes later, there remains no practical and meaningful definition for spinal instability in thoracolumbar trauma. Surgeon expertise and experience remains an important factor in stability determination. We propose that, at an initial assessment, a distinction should be made between immediate and delayed instability. This designation should better guide surgeons in decision making and patient counseling.
THE SUSTAINABILITY OF THE FISCAL-BUDGETARY POLICY IN THE CONTEXT OF TAXATION SYSTEM REDUCTION
Directory of Open Access Journals (Sweden)
Cristian MOCAN
2015-08-01
Full Text Available The estimation of the budgetary impact determined by the Government’s proposition of modifying Law no. 571/2003 regarding the Fiscal code, respectively the diminution of the central levies and taxes (VAT, profit tax, income tax, microenterprises’ income tax, excises, etc., represents a mandatory condition provided by the legislation in the field, having as primary role the observance of the fiscal budgetary policy’s objectives on medium-term and long-term assumed by Romania through the Treaty regarding the stability, coordination and governance in the European Union. The tax sustainability on medium-term and long-term supposes that the Government promotes a cautious fiscal-budgetary policy and an efficient administration of the appeared risks that wouldn’t imply adjustments of the expenses, incomes or a budgetary deficit with adverse economic and social effects.This work intends to analyze the financial impact on Romania’s budget following the proposition of the Government to reduce the central levies and taxes, the opportunity of adopting a high fiscal relaxation while observing the medium-term and long-term budgetary objectives and the consolidation of the existing macroeconomic balances. The data used in the proposed scientific work takes into consideration the estimated VAT and GDP for 2015-2017 in Romania. The set of used data was available in the database of ANAF and the data provided in the Fiscal budgetary strategy 2015-2017.The results of the study highlight the importance of the correct dimensioning of the effects of the first round and those of the second round represented by the fiscal relaxation measures in the revision project of law no. 571/2003 regarding the Fiscal code in the context of using fiscal multipliers and the elasticity of the budgetary aggregates.
Fiscal ethics, policies, and theories
Directory of Open Access Journals (Sweden)
Andrés Blanco
2016-08-01
Full Text Available The connections between ethics, policies and economic theories regarding fiscal matters need a more thorough analysis than the one carried out so far. On one hand, even though there are some ethical proposals on taxation, in general such proposals have not been grounded on explanatory theories of the economy. On the other hand, schools of thought about economy usually fail to ethically justify their political proposals. However, such distinctions cannot be sustained rationally: any ethical proposal concerning fiscal matters involves an explanation of economy, and conversely any proposal related to fiscal policies does not only involve a theory but also an ethical understanding. This article will review such connections, and general conclusions will be applied to two specific cases: first, Rawls’s proposal concerning taxation will be reviewed, having previously studied its descriptive assumptions, and then the lack of an ethical connection between the post Keynesian theory on the monetary circuit and its fiscal proposal will be examined. Finally, a possible “taxation compliance ethic” of tax-payers will be likewise analysed.
2010-04-29
... the U.S. Department of the Treasury, Financial Management Service, Financial Accounting and Services..., 2010. Sandra Paylor-Sanders, Acting Director, Financial Accounting and Services Division. [FR Doc. 2010... Bonding Company AGENCY: Financial Management Service, Fiscal Service, Department of the Treasury. ACTION...
2012-05-31
... of the Treasury, Financial Management Service, Financial Accounting and Services Division, Surety... Carrico, Director, Financial Accounting and Services Division. [FR Doc. 2012-13044 Filed 5-30-12; 8:45 am...: Alterra Reinsurance USA, Inc. AGENCY: Financial Management Service, Fiscal Service, Department of the...
Political Consensus and Fiscal Outcomes
DEFF Research Database (Denmark)
Houlberg, Kurt; Holm Pedersen, Lene
2015-01-01
It is becoming difficult to maintain consensus in a period of economic austerity, and this possibly challenges the ability of democratic institutions to take decisions on tough economic questions. In order to find out how political consensus influences fiscal outcomes, this article sets out...
Low-frequency instabilities of a warm plasma in a magnetic field
International Nuclear Information System (INIS)
Smith, D.F.; Hollweg, J.V.
1977-01-01
The marginal stability of a plasma carrying current along the static magnetic field with isotropic Maxwellian ions and isotropic Maxwellian electrons drifting relative to the ions is investigated. The complete electromagnetic dispersion relation is studied using numerical techniques; the electron sums are restricted to three terms which limits the analysis to frequencies much less than the electron gyro-frequency, but includes frequencies somewhat above the ion gyro-frequency. A 'kink-like' instability and an instability of the Alfven mode are found to have the lowest threshold drift velocities in most cases. In fact the threshold drift for the kink-like instability can be significantly less than the ion thermal speed. Electrostatic and electromagnetic ion-cyclotron instabilities are also found as well as the electro-static ion-acoustic instability. No instability of the fast magnetosonic mode was found. The stability analysis provides only threshold drift velocities and gives no information about growth rates. (author)
Instabilities due to anisotropic velocity distributions. Progress report, June 1, 1974--June 1, 1975
International Nuclear Information System (INIS)
Harris, E.G.
1975-01-01
A continuing theoretical study of plasma instabilities and related phenomena including nonlinear effects, particle and energy transport and heating schemes is presented. In the past year, a study of linear resistive instabilities with applications to Tokamaks was almost completed and is being prepared for publication. A sigma stability analysis is being worked on at the present time. Some thought was given to a nonlinear resistive instability analysis but not much progress has been made. A study of equilibrium and stability of elliptical cross section Tokamaks was completed. Considerable work was completed on plasma heating by rf waves at the lower hybrid frequency and by Alfven waves. This work is continuing. A study of instabilities excited by runaway beams of electrons in Tokamaks was largly completed. Some work was done on trapped particle instabilities in Tokamaks and their relation to other instabilities driven by gradients of density or temperature. Work is underway on diffusion and thermal conduction in the bumpy torus. (U.S.)
Nonideal magnetohydrodynamic instabilities and toroidal magnetic confinement
International Nuclear Information System (INIS)
Furth, H.P.
1985-05-01
The marked divergence of experimentally observed plasma instability phenomena from the predictions of ideal magnetohydrodynamics led in the early 1960s to the formulations of finite-resistivity stability theory. Beginning in the 1970s, advanced plasma diagnostics have served to establish a detailed correspondence between the predictions of the finite-resistivity theory and experimental plasma behavior - particularly in the case of the resistive kink mode and the tokamak plasma. Nonlinear resistive-kink phenomena have been found to govern the transport of magnetic flux and plasma energy in the reversed-field pinch. The other predicted finite-resistivity instability modes have been more difficult to identify directly and their implications for toroidal magnetic confinement are still unresolved
Instability and dynamics of volatile thin films
Ji, Hangjie; Witelski, Thomas P.
2018-02-01
Volatile viscous fluids on partially wetting solid substrates can exhibit interesting interfacial instabilities and pattern formation. We study the dynamics of vapor condensation and fluid evaporation governed by a one-sided model in a low-Reynolds-number lubrication approximation incorporating surface tension, intermolecular effects, and evaporative fluxes. Parameter ranges for evaporation-dominated and condensation-dominated regimes and a critical case are identified. Interfacial instabilities driven by the competition between the disjoining pressure and evaporative effects are studied via linear stability analysis. Transient pattern formation in nearly flat evolving films in the critical case is investigated. In the weak evaporation limit unstable modes of finite-amplitude nonuniform steady states lead to rich droplet dynamics, including flattening, symmetry breaking, and droplet merging. Numerical simulations show that long-time behaviors leading to evaporation or condensation are sensitive to transitions between filmwise and dropwise dynamics.
Deployment Instabilities of Lobed-Pumpkin Balloon
Nakashino, Kyoichi
A lobed-pumpkin balloon, currently being developed in ISAS/JAXA as well as in NASA, is a promising vehicle for long duration scientific observations in the stratosphere. Recent ground and flight experiments, however, have revealed that the balloon has deployment instabilities under certain conditions. In order to overcome the instability problems, a next generation SPB called 'tawara' type balloon has been proposed, in which an additional cylindrical part is appended to the standard lobed-pumpkin balloon. The present study investigates the deployment stability of tawara type SPB in comparison to that of standard lobed-pumpkin SPB through eigenvalue analysis on the basis of finite element methods. Our numerical results show that tawara type SPB enjoys excellent deployment performance over the standard lobed-pumpkin SPBs.
Hydrodynamic instabilities in inertial confinement fusion
International Nuclear Information System (INIS)
Freeman, J.R.
1977-01-01
Inertial confinement fusion targets generally consist of hollow high-density spheres filled with low density thermonuclear fuel. Targets driven ablatively by electrons, ions, or lasers are potentially unstable during the initial acceleration phase. Later in time, the relatively low density fuel decelerates the dense inner portion of the sphere (termed the pusher), permitting unstable growth at the fuel-pusher interface. The instabilities are of the Rayleigh-Taylor variety, modified by thermal and viscous diffusion and convection. These problems have been analyzed by many in recent years using both linearized perturbation methods and direct numerical simulation. Examples of two-dimensional simulations of the fuel-pusher instability in electron beam fusion targets will be presented, along with a review of possible stabilization mechanisms
CFD simulation of Kelvin-Helmholtz instability
International Nuclear Information System (INIS)
Strubelj, L.; Tiselj, I.
2005-01-01
Kelvin-Helmholtz instability appears in stratified two-fluid flow at surface. When the relative velocity is higher than the critical relative velocity, the growth of waves occurs. The experiment of Thorpe [1] used as a benchmark in the present paper, is made in a rectangular glass tube filled with two immiscible fluids of various densities. We simulated the growth of instability with CFX-5.7 code and compared simulation with analytical solution. It was found that surface tension force, which stabilizes growth of waves, actually has a destabilizing effect in simulation, unless very small timestep and residual is used. In CFX code system of nonlinear Navier-Stokes equations is linearised and solved iterative in each timestep, until prescribed residual is achieved. On the other hand, simulation without surface tension force is more stable than analytical result predicts. (author)
Instabilities in strongly coupled plasmas
Kalman, G J
2003-01-01
The conventional Vlasov treatment of beam-plasma instabilities is inappropriate when the plasma is strongly coupled. In the strongly coupled liquid state, the strong correlations between the dust grains fundamentally affect the conditions for instability. In the crystalline state, the inherent anisotropy couples the longitudinal and transverse polarizations, and results in unstable excitations in both polarizations. We summarize analyses of resonant and non-resonant, as well as resistive instabilities. We consider both ion-dust streaming and dust beam-plasma instabilities. Strong coupling, in general, leads to an enhancement of the growth rates. In the crystalline phase, a resonant transverse instability can be excited.
Orphans and political instability.
Breuning, Marijke; Ishiyama, John
2011-01-01
This study investigates the security implications of growing orphan populations, particularly in Sub-Saharan Africa. Little has been written about the security implications of this especially vulnerable group of children. Are growing orphan populations associated with increases in political instability as has been suggested? Using data from several sources, we employ regression analysis to test whether Sub-Saharan African countries with larger proportions of orphans and those with increasing orphan populations experience higher rates of political instability. We find that the increase in the orphan population is related to an increasing incidence of civil conflict, but do not find a similar relationship for the proportion of orphans. In addition, we find that the causes of orphanhood matter. We conclude that increases in orphan populations (rather than simple proportions) are destabilizing. We suggest possible avenues for mediating the security risks posed by growing orphan populations.
Bossa, Benjamin
2005-11-01
We address the problem of the free fall of a long, horizontal and narrow liquid layer squeezed in a vertical open Hele-Shaw cell. The layer destabilizes as it falls down, evolving into a series of liquid blobs linked together by thin bridges, which ultimately break, leaving the initially connex fluid layer as a set a disjointed drops. The mechanism of this instability is the onset of a vertical pressure gradient due to the curvature difference of the moving contact line between the advancing interface and the rear interface. This instability, whose growth rate scales with a non-trivial power of the capillary number, amplifies indifferently a broad band of wavenumbers because of the flat shape of its dispersion relation in the thin layer limit. We will finally comment on the nature of the final fragmentation process and drop size distributions.
Instability and internet design
Directory of Open Access Journals (Sweden)
Sandra Braman
2016-09-01
Full Text Available Instability - unpredictable but constant change in one’s environment and the means with which one deals with it - has replaced convergence as the focal problem for telecommunications policy in general and internet policy in particular. Those who designed what we now call the internet during the first decade of the effort (1969-1979, who in essence served simultaneously as its policy-makers, developed techniques for coping with instability of value for network designers today and for those involved with any kind of large-scale sociotechnical infrastructure. Analysis of the technical document series that was medium for and record of that design process reveals coping techniques that began with defining the problem and went on to include conceptual labour, social practices, and technical approaches.
Imaging of patellofemoral instability
International Nuclear Information System (INIS)
Waldt, S.; Rummeny, E.J.
2012-01-01
Patellofemoral instability remains a diagnostic and therapeutic challenge due to its multifactorial genesis. The purpose of imaging is to systematically analyze predisposing factors, such as trochlear dysplasia, patella alta, tibial tuberosity-trochlear groove (TT-TG) distance, rotational deformities of the lower limb and patellar tilt. In order to evaluate anatomical abnormalities with a sufficient diagnostic accuracy, standardized measurement methods and implementation of various imaging modalities are necessary. Diagnosis of acute and often overlooked lateral patellar dislocation can be established with magnetic resonance imaging (MRI) because of its characteristic patterns of injury. Damage to the medial patellofemoral ligament (MPFL) has a significance just as high as the predisposing risk factors in relation to the cause of chronic instability. (orig.) [de
International Nuclear Information System (INIS)
Dorfi, E.A.; Drury, L.O.
1985-01-01
The interaction between energetic charged particles and thermal plasma, which forms the basis of diffusive shock acceleration, leads also to interesting dynamical phenomena. For a compressional mode propagating in a system with homoeneous energetic particle pressure it is well known that friction with the energetic particles leads to damping. The linear theory of this effect has been analyzed in detail by Ptuskin. Not so obvious is that a non-uniform energetic particle pressure can in addition amplify compressional disturbances. If the pressure gradient is sufficiently steep this growth can dominate the frictional damping and lead to an instability. It is important to not that this effect results from the collective nature of the interaction between the energetic particles and the gas and is not connected with the Parker instability, nor with the resonant amplification of Alfven waves
Tearing mode instability due to anomalous resistivity
International Nuclear Information System (INIS)
Furuya, Atsushi; Itoh, Sanae I.; Yagi, Masatoshi
2000-01-01
Tearing mode instability in the presence of microscopic truculence is investigates. The effects of microscopic turbulence on tearing mode are taken as drags which are calculated by one-point renormalization method and mean-field approximation. These effects are reduced to effective diffusivities in reduced MHD equations. Using these equations, the stability analyses of the tearing mode are performed. It is shown that a finite amplitude of fluctuation enhances the growth rate of tearing mode. For very high values of turbulent diffusivities, marginally stable state exists. The effects of each turbulent diffusivity on mode stability are examined near marginal stability boundary. Parameter dependence of the resistive ballooning mode turbulence on tearing mode is analyzed as an example. (author)
Instability of single-phase natural circulation
International Nuclear Information System (INIS)
Xie Heng; Zhang Jinling; Jia Dounan
1997-01-01
The author has investigated the instability of single-phase flows in natural circulation loops. The momentum equation and energy equation are made dimensionless according to some definitions, and some important dimensionless parameters are gotten. The authors decomposed the mean mass flowrate and temperature into a steady solution and a small disturbance equations. Through solving the disturbance equations, the authors get the neutral stability curves. The authors have studied the effect of the two parameters which represent the ratio of buoyancy force to the friction loss in the loop on the stability of loops. The authors also have studied the effect of the difference of height between the center of heat source and the heat sink on the stability
The Impact of the Great Recession on Monetary and Fiscal Policy in Developed Market Economies
Directory of Open Access Journals (Sweden)
Šehović Damir
2015-03-01
Full Text Available Background: With the occurrence of the crisis in 2007, which caused the largest economic contraction since the Great Depression in the thirties, it has become evident that the previous understanding of strategies, effects and roles of monetary and fiscal policy should be redefined. Objectives: The aim of this paper is to illustrate a possible expected change in monetary and fiscal policy in developed market economies that could occur as a consequence of the Great Recession. Methods/Approach: The paper provides a comparative analysis of various primary economic variables related to the developed OECD countries, as well as the empirical testing of the selected theoretical assumptions. Results: The changes in monetary policy refer to the question of raising target inflation, considering a possible use of aggregate price level targeting and paying attention to the role of central banks in suppressing the formation of an asset bubble. The success of fiscal policy in attaining stabilization depends on the size of possible fiscal measures and creation of automatic stabilizers. Conclusions: For the most part, monetary and fiscal policies will still stay unchanged, although some segments of these policies need to be improved.
Instability in dynamic fracture
Fineberg, J.; Marder, M.
1999-05-01
The fracture of brittle amorphous materials is an especially challenging problem, because the way a large object shatters is intimately tied to details of cohesion at microscopic scales. This subject has been plagued by conceptual puzzles, and to make matters worse, experiments seemed to contradict the most firmly established theories. In this review, we will show that the theory and experiments fit within a coherent picture where dynamic instabilities of a crack tip play a crucial role. To accomplish this task, we first summarize the central results of linear elastic dynamic fracture mechanics, an elegant and powerful description of crack motion from the continuum perspective. We point out that this theory is unable to make predictions without additional input, information that must come either from experiment, or from other types of theories. We then proceed to discuss some of the most important experimental observations, and the methods that were used to obtain the them. Once the flux of energy to a crack tip passes a critical value, the crack becomes unstable, and it propagates in increasingly complicated ways. As a result, the crack cannot travel as quickly as theory had supposed, fracture surfaces become rough, it begins to branch and radiate sound, and the energy cost for crack motion increases considerably. All these phenomena are perfectly consistent with the continuum theory, but are not described by it. Therefore, we close the review with an account of theoretical and numerical work that attempts to explain the instabilities. Currently, the experimental understanding of crack tip instabilities in brittle amorphous materials is fairly detailed. We also have a detailed theoretical understanding of crack tip instabilities in crystals, reproducing qualitatively many features of the experiments, while numerical work is beginning to make the missing connections between experiment and theory.
PRINCIPLES AND PROCEDURES ON FISCAL
Directory of Open Access Journals (Sweden)
Morar Ioan Dan
2011-07-01
Full Text Available Fiscal science advertise in most analytical situations, while the principles reiterated by specialists in the field in various specialized works The two components of taxation, the tax system relating to the theoretical and the practical procedures relating to tax are marked by frequent references and invocations of the underlying principles to tax. This paper attempts a return on equity fiscal general vision as a principle often invoked and used to justify tax policies, but so often violated the laws fiscality . Also want to emphasize the importance of devising procedures to ensure fiscal equitable treatment of taxpayers. Specific approach of this paper is based on the notion that tax equity is based on equality before tax and social policies of the executive that would be more effective than using the other tax instruments. I want to emphasize that if the scientific approach to justify the unequal treatment of the tax law is based on the various social problems of the taxpayers, then deviates from the issue of tax fairness justification explaining the need to promote social policies usually more attractive to taxpayers. Modern tax techniques are believed to be promoted especially in order to ensure an increasing level of high efficiency at the expense of the taxpayers obligations to ensure equality before the law tax. On the other hand, tax inequities reaction generates multiple recipients from the first budget plan, but finalities unfair measures can not quantify and no timeline for the reaction, usually not known. But while statistics show fluctuations in budgetary revenues and often find in literature reviews and analysis relevant to a connection between changes in government policies, budget execution and outcome. The effects of inequality on tax on tax procedures and budgetary revenues are difficult to quantify and is among others to this work. Providing tax equity without combining it with the principles of discrimination and neutrality
Relativistic centrifugal instability
Gourgouliatos, Konstantinos N.; Komissarov, Serguei S.
2018-03-01
Near the central engine, many astrophysical jets are expected to rotate about their axis. Further out they are expected to go through the processes of reconfinement and recollimation. In both these cases, the flow streams along a concave surface and hence, it is subject to the centrifugal force. It is well known that such flows may experience the centrifugal instability (CFI), to which there are many laboratory examples. The recent computer simulations of relativistic jets from active galactic nuclei undergoing the process of reconfinement show that in such jets CFI may dominate over the Kelvin-Helmholtz instability associated with velocity shear (Gourgouliatos & Komissarov). In this letter, we generalize the Rayleigh criterion for CFI in rotating fluids to relativistic flows using a heuristic analysis. We also present the results of computer simulations which support our analytic criterion for the case of an interface separating two uniformly rotating cylindrical flows. We discuss the difference between CFI and the Rayleigh-Taylor instability in flows with curved streamlines.
Ion temperature gradient instability
International Nuclear Information System (INIS)
1989-01-01
Anomalous ion thermal conductivity remains an open physics issue for the present generation of high temperature Tokamaks. It is generally believed to be due to Ion Temperature Gradient Instability (η i mode). However, it has been difficult, if not impossible to identify this instability and study the anomalous transport due to it, directly. Therefore the production and identification of the mode is pursued in the simpler and experimentally convenient configuration of the Columbia Linear Machine (CLM). CLM is a steady state machine which already has all the appropriate parameters, except η i . This parameter is being increased to the appropriate value of the order of 1 by 'feathering' a tungsten screen located between the plasma source and the experimental cell to flatten the density profile and appropriate redesign of heating antennas to steepen the ion temperature profile. Once the instability is produced and identified, a thorough study of the characteristics of the mode can be done via a wide range of variation of all the critical parameters: η i , parallel wavelength, etc
COMPARATIVE STUDY ON ACCOUNTING AND FISCAL AMORTIZATION
Directory of Open Access Journals (Sweden)
MARIANA GURAU
2012-05-01
Full Text Available Placed in the international trend, Romanian accounting had experienced various changes, especially as regards of progress on disconnection between accounting and fiscality. In the present, fiscal rules should not have any role in accounting decisions, because accounting rules are applied to produce accounting information that is useful in making decisions and to provide a "true and fair view" upon financial reality of the entity. However, the barrier in the habit of accounting to thinking for fiscal point of view all economic transactions remains insurmountable, yet. Starting from this perspective on disconnection between accounting and fiscality would mean that amortization recorded in the accounting, as a result of management policy, to be different from fiscality amortization, to calculate income tax. Although formally accepted, disconnect between accounting and fiscality continues to meet many difficulties. In this sense, it is usual in practice to use the same method of amortization for accounting purposes and for fiscal purposes to prevent complications of double track amortization and prevent wandering in the rules in this field. Accounting rule is deliberately eluded in favor of the fiscal rules. This is the reason we proposed to make in this paper a comparative study between norms and rules on accounting and fiscal amortization, paper in which we intend to show the benefits of applying accounting and fiscal rules separately.
Resilience of quasi-isodynamic stellarators against trapped-particle instabilities.
Proll, J H E; Helander, P; Connor, J W; Plunk, G G
2012-06-15
It is shown that in perfectly quasi-isodynamic stellarators, trapped particles with a bounce frequency much higher than the frequency of the instability are stabilizing in the electrostatic and collisionless limit. The collisionless trapped-particle instability is therefore stable as well as the ordinary electron-density-gradient-driven trapped-electron mode. This result follows from the energy balance of electrostatic instabilities and is thus independent of all other details of the magnetic geometry.
The Rayleigh-Taylor instability in inertial fusion, astrophysical plasma and flames
International Nuclear Information System (INIS)
Bychkov, V; Modestov, M; Akkerman, V; Eriksson, L-E
2007-01-01
Previous results are reviewed and new results are presented on the Rayleigh-Taylor instability in inertial confined fusion, flames and supernovae including gravitational and thermonuclear explosion mechanisms. The instability couples micro-scale plasma effects to large-scale hydrodynamic phenomena. In inertial fusion the instability reduces target compression. In supernovae the instability produces large-scale convection, which determines the fate of the star. The instability is often accompanied by mass flux through the unstable interface, which may have either a stabilizing or a destabilizing influence. Destabilization happens due to the Darrieus-Landau instability of a deflagration front. Still, it is unclear whether the instabilities lead to well-organized large-scale structures (bubbles) or to relatively isotropic turbulence (mixing layer)
Instabilities and vortex dynamics in shear flow of magnetized plasmas
International Nuclear Information System (INIS)
Tajima, T.; Horton, W.; Morrison, P.J.; Schutkeker, J.; Kamimura, T.; Mima, K.; Abe, Y.
1990-03-01
Gradient-driven instabilities and the subsequent nonlinear evolution of generated vortices in sheared E x B flows are investigated for magnetized plasmas with and without gravity (magnetic curvature) and magnetic shear by using theory and implicit particle simulations. In the linear eigenmode analysis, the instabilities considered are the Kelvin-Helmholtz (K-H) instability and the resistive interchange instability. The presence of the shear flow can stabilize these instabilities. The dynamics of the K-H instability and the vortex dynamics can be uniformly described by the initial flow pattern with a vorticity localization parameter ε. The observed growth of the K-H modes is exponential in time for linearly unstable modes, secular for marginal mode, and absent until driven nonlinearly for linearly stable modes. The distance between two vortex centers experiences rapid merging while the angle θ between the axis of vortices and the external shear flow increases. These vortices proceed toward their overall coalescence, while shedding small-scale vortices and waves. The main features of vortex dynamics of the nonlinear coalescence and the tilt or the rotational instabilities of vortices are shown to be given by using a low dimension Hamiltonian representation for interacting vortex cores in the shear flow. 24 refs., 19 figs., 1 tab
Nonlinear Development and Secondary Instability of Traveling Crossflow Vortices
Li, Fei; Choudhari, Meelan M.; Duan, Lian; Chang, Chau-Lyan
2014-01-01
Transition research under NASA's Aeronautical Sciences Project seeks to develop a validated set of variable fidelity prediction tools with known strengths and limitations, so as to enable "sufficiently" accurate transition prediction and practical transition control for future vehicle concepts. This paper builds upon prior effort targeting the laminar breakdown mechanisms associated with stationary crossflow instability over a swept-wing configuration relevant to subsonic aircraft with laminar flow technology. Specifically, transition via secondary instability of traveling crossflow modes is investigated as an alternate scenario for transition. Results show that, for the parameter range investigated herein, secondary instability of traveling crossflow modes becomes insignificant in relation to the secondary instability of the stationary modes when the relative initial amplitudes of the traveling crossflow instability are lower than those of the stationary modes by approximately two orders of magnitudes or more. Linear growth predictions based on the secondary instability theory are found to agree well with those based on PSE and DNS, with the most significant discrepancies being limited to spatial regions of relatively weak secondary growth, i.e., regions where the primary disturbance amplitudes are smaller in comparison to its peak amplitude. Nonlinear effects on secondary instability evolution is also investigated and found to be initially stabilizing, prior to breakdown.
Two-phase flow instabilities in a vertical annular channel
Energy Technology Data Exchange (ETDEWEB)
Babelli, I.; Nair, S.; Ishii, M. [Purdue Univ., West Lafayette, IN (United States)
1995-09-01
An experimental test facility was built to study two-phase flow instabilities in vertical annular channel with emphasis on downward flow under low pressure and low flow conditions. The specific geometry of the test section is similar to the fuel-target sub-channel of the Savannah River Site (SRS) Mark 22 fuel assembly. Critical Heat Flux (CHF) was observed following flow excursion and flow reversal in the test section. Density wave instability was not recorded in this series of experimental runs. The results of this experimental study show that flow excursion is the dominant instability mode under low flow, low pressure, and down flow conditions. The onset of instability data are plotted on the subcooling-Zuber (phase change) numbers stability plane.
Rayleigh-Taylor instability of cylindrical jets with radial motion
Energy Technology Data Exchange (ETDEWEB)
Chen, Xiang M. [GE Nuclear, Wilmington, NC (United States); Schrock, V.E.; Peterson, P.F. [Univ. of California, Berkeley, CA (United States)
1995-09-01
Rayleigh-Taylor instability of an interface between fluids with different densities subjected to accelleration normal to itself has interested researchers for almost a century. The classic analyses of a flat interface by Rayleigh and Taylor have shown that this type of instability depends on the direction of acceleration and the density differences of the two fluids. Plesset later analyzed the stability of a spherically symmetric flows (and a spherical interface) and concluded that the instability also depends on the velocity of the interface as well as the direction and magnitude of radial acceleration. The instability induced by radial motion in cylindrical systems seems to have been neglected by previous researchers. This paper analyzes the Rayleigh-Taylor type of the spherical case, the radial velocity also plays an important role. As an application, the example of a liquid jet surface in an Inertial Confinement Fusion (ICF) reactor design is analyzed.
Ordinary mode instability associated with thermal ring distribution
Hadi, F.; Yoon, P. H.; Qamar, A.
2015-02-01
The purely growing ordinary (O) mode instability driven by excessive parallel temperature anisotropy has recently received renewed attention owing to its potential applicability to the solar wind plasma. Previous studies of O mode instability have assumed either bi-Maxwellian or counter-streaming velocity distributions. For solar wind plasma trapped in magnetic mirror-like geometry such as magnetic clouds or in the vicinity of the Earth's collisionless bow shock environment, however, the velocity distribution function may possess a loss-cone feature. The O-mode instability in such a case may be excited for cyclotron harmonics as well as the purely growing branch. The present paper investigates the O-mode instability for plasmas characterized by the parallel Maxwellian distribution and perpendicular thermal ring velocity distribution in order to understand the general stability characteristics.
Ordinary mode instability associated with thermal ring distribution
Energy Technology Data Exchange (ETDEWEB)
Hadi, F.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742 (United States); School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of)
2015-02-15
The purely growing ordinary (O) mode instability driven by excessive parallel temperature anisotropy has recently received renewed attention owing to its potential applicability to the solar wind plasma. Previous studies of O mode instability have assumed either bi-Maxwellian or counter-streaming velocity distributions. For solar wind plasma trapped in magnetic mirror-like geometry such as magnetic clouds or in the vicinity of the Earth's collisionless bow shock environment, however, the velocity distribution function may possess a loss-cone feature. The O-mode instability in such a case may be excited for cyclotron harmonics as well as the purely growing branch. The present paper investigates the O-mode instability for plasmas characterized by the parallel Maxwellian distribution and perpendicular thermal ring velocity distribution in order to understand the general stability characteristics.
Nutation instability of spinning solid rocket motor spacecraft
Directory of Open Access Journals (Sweden)
Dan YANG
2017-08-01
Full Text Available The variation of mass, and moment of inertia of a spin-stabilized spacecraft leads to concern about the nutation instability. Here a careful analysis on the nutation instability is performed on a spacecraft propelled by solid rocket booster (SRB. The influences of specific solid propellant designs on transversal angular velocity are discussed. The results show that the typical SRB of End Burn suppresses the non-principal axial angular velocity. On the contrary, the frequently used SRB of Radial Burn could amplify the transversal angular velocity. The nutation instability caused by a design of Radial Burn could be remedied by the addition of End Burn at the same time based on the study of the combination design of both End Burn and Radial Burn. The analysis of the results proposes the design conception of how to control the nutation motion. The method is suitable to resolve the nutation instability of solid rocket motor with complex propellant patterns.
The portrait of eikonal instability in Lovelock theories
Konoplya, R. A.; Zhidenko, A.
2017-05-01
Perturbations and eikonal instabilities of black holes and branes in the Einstein-Gauss-Bonnet theory and its Lovelock generalization were considered in the literature for several particular cases, where the asymptotic conditions (flat, dS, AdS), the number of spacetime dimensions D, non-vanishing coupling constants (α1, α2, α3 etc.) and other parameters have been chosen in a specific way. Here we give a comprehensive analysis of the eikonal instabilities of black holes and branes for the most general Lovelock theory, not limited by any of the above cases. Although the part of the stability analysis is performed here purely analytically and formulated in terms of the inequalities for the black hole parameters, the most general case is treated numerically and the accurate regions of instabilities are presented. The shared Mathematica® code allows the reader to construct the regions of eikonal instability for any desired values of the parameters.
COMPARATIVE STUDY ON FISCAL-ADMINISTRATIVE SOLICITOR'S OFFICE AND FISCAL SOLICITOR'S OFFICE
OCTAVIA MARIA CILIBIU
2012-01-01
The fiscal-administrative solicitor's office represents the activity of solving litigations between tax payers and the fiscal administration, litigations whose purpose is to cancel totally or partially a fiscal administrative document, document considered by the tax payer harmful for his legitimate right or interest recognized by law. The fiscal solicitor's office represents the activity of solving litigations whose purpose is to cancel or correction of acts of enforcement of tax claims. Rese...
On plasma stability under anisotropic random electric field influence
International Nuclear Information System (INIS)
Rabich, L.N.; Sosenko, P.P.
1987-01-01
The influence of anisotropic random field on plasma stability is studied. The thresholds and instability increments are obtained. The stabilizing influence of frequency missmatch and external magnetic field is pointed out
Feedback stabilization of axisymmetric modes in tokamaks
International Nuclear Information System (INIS)
Jardin, S.C.; Larrabee, D.A.
1982-01-01
Noncircular tokamak plasmas can be unstable to ideal MHD axisymmetric instabilities. Passive conductors with finite resistivity will at best slow down these instabilities to the resistive (L/R) time of the conductors. An active feedback system far from the plasma which responds on this resistive time can stabilize the system provided its mutual inductance with the passive coils is small enough
Effect of the thermal spread in a beam on the radiative Pierce instability
International Nuclear Information System (INIS)
Klochkov, D.N.; Pekar, M.Yu.; Rukhadze, A.A.
1999-01-01
The linear dynamics of the radiative Pierce instability in a single plane in the case of the relativistic electron beam with T temperature stabilized through a strong magnetic field, is considered. It is shown that the instability increment decreases with the thermal spread growth [ru
Surface wave instability in bounded magnetized plasma with inhomogeneous particle stream
Energy Technology Data Exchange (ETDEWEB)
Jovanovic, D.; Vukovic, S. (Belgrade Univ. (Yugoslavia). Inst. za Fiziku)
1981-02-01
The instability of surface wave modes in a semi infinite magnetoactive plasma with a non-homogeneous particle stream is studied. The existence of two possible mechanisms for the development of the instability: induced anomalous Doppler effect and induced Cherenkov effect is demonstrated. Related growth-rates and stability criteria are calculated.
Surface wave instability in bounded magnetized plasma with inhomogeneous particle stream
International Nuclear Information System (INIS)
Jovanovic, D.; Vukovic, S.
1981-01-01
The instability of surface wave modes in a semi infinite magnetoactive plasma with a non-homogeneous particle stream is studied. The existence of two possible mechanisms for the development of the instability: induced anomalous Doppler effect and induced Cherenkov effect is demonstrated. Related growth-rates and stability criteria are calculated. (author)
Landau Damping of Beam Instabilities by Electron Lenses
Energy Technology Data Exchange (ETDEWEB)
Shiltsev, V. [Fermilab; Alexahin, Yuri; Burov, A. [Fermilab; Valishev, A. [Fermilab
2017-06-26
Modern and future particle accelerators employ increasingly higher intensity and brighter beams of charged particles and become operationally limited by coherent beam instabilities. Usual methods to control the instabilities, such as octupole magnets, beam feedback dampers and use of chromatic effects, become less effective and insufficient. We show that, in contrast, Lorentz forces of a low-energy, a magnetically stabilized electron beam, or "electron lens", easily introduces transverse nonlinear focusing sufficient for Landau damping of transverse beam instabilities in accelerators. It is also important that, unlike other nonlinear elements, the electron lens provides the frequency spread mainly at the beam core, thus allowing much higher frequency spread without lifetime degradation. For the parameters of the Future Circular Collider, a single conventional electron lens a few meters long would provide stabilization superior to tens of thousands of superconducting octupole magnets.
Study on flow instabilities in two-phase mixtures
International Nuclear Information System (INIS)
Ishii, M.
1976-03-01
Various mechanisms that can induce flow instabilities in two-phase flow systems are reviewed and their relative importance discussed. In view of their practical importance, the density-wave instabilities have been analyzed in detail based on the one-dimensional two-phase flow formulation. The dynamic response of the system to the inlet flow perturbations has been derived from the model; thus the characteristic equation that predicts the onset of instabilities has been obtained. The effects of various system parameters, such as the heat flux, subcooling, pressure, inlet velocity, inlet orificing, and exit orificing on the stability boundary have been analyzed. In addition to numerical solutions, some simple stability criteria under particular conditions have been obtained. Both results have been compared with various experimental data, and a satisfactory agreement has been demonstrated
CSIR Research Space (South Africa)
Cooper, Antony K
2010-10-01
Full Text Available Conventionally in formal concept analysis (FCA), concept stability is preferred in the lattice, because instability (i.e. low stability) represents noise that clouds the analysis of the data. However, high concept stability means that there are many...
Rotation influence on the plasma helical instability
International Nuclear Information System (INIS)
Gutkin, T.I.; Tsypin, V.S.; Boleslavskaya, G.I.
1980-01-01
The influence of the rotation on helical instability of a plasma with the fixed boundaries (HIFB) is investigated taking into account the compressibility. A case of infinitely long cylinder with distributed current is considered. Cases when a rotating plasma is confined by current magnetic field are analytically considered. It is shown that in the case of the fixed boundary taking into account the compressibility in the HIFB increment increases and the picture of the rotation influence on HIFB considerably changes. Besides, it is shown that in the case of high plasma pressures HIFB can stabilize as a result of the rotation
Erosion waves: Transverse instabilities and fingering
Malloggi, F.; Lanuza, J.; Andreotti, B.; Clément, E.
2006-09-01
Two laboratory scale experiments of dry and underwater avalanches of non-cohesive granular materials are investigated. We trigger solitary waves and study the conditions under which the front is transversally stable. We show the existence of a linear instability followed by a coarsening dynamics and finally the onset of a fingering pattern. Due to the different operating conditions, both experiments strongly differ by the spatial and time scales involved. Nevertheless, the quantitative agreement between the stability diagram, the wavelengths selected and the avalanche morphology suggest a common scenario for an erosion/deposition process.
Bifurcation theory for toroidal MHD instabilities
International Nuclear Information System (INIS)
Maschke, E.K.; Morros Tosas, J.; Urquijo, G.
1992-01-01
Using a general representation of magneto-hydrodynamics in terms of stream functions and potentials, proposed earlier, a set of reduced MHD equations for the case of toroidal geometry had been derived by an appropriate ordering with respect to the inverse aspect ratio. When all dissipative terms are neglected in this reduced system, it has the same linear stability limits as the full ideal MHD equations, to the order considered. When including resistivity, thermal conductivity and viscosity, we can apply bifurcation theory to investigate nonlinear stationary solution branches related to various instabilities. In particular, we show that a stationary solution of the internal kink type can be found
System Detects Vibrational Instabilities
Bozeman, Richard J., Jr.
1990-01-01
Sustained vibrations at two critical frequencies trigger diagnostic response or shutdown. Vibration-analyzing electronic system detects instabilities of combustion in rocket engine. Controls pulse-mode firing of engine and identifies vibrations above threshold amplitude at 5.9 and/or 12kHz. Adapted to other detection and/or control schemes involving simultaneous real-time detection of signals above or below preset amplitudes at two or more specified frequencies. Potential applications include rotating machinery and encoders and decoders in security systems.
Evaporation and Antievaporation Instabilities
Directory of Open Access Journals (Sweden)
Andrea Addazi
2017-10-01
Full Text Available We review (antievaporation phenomena within the context of quantum gravity and extended theories of gravity. The (antievaporation effect is an instability of the black hole horizon discovered in many different scenarios: quantum dilaton-gravity, f ( R -gravity, f ( T -gravity, string-inspired black holes, and brane-world cosmology. Evaporating and antievaporating black holes seem to have completely different thermodynamical features compared to standard semiclassical black holes. The purpose of this review is to provide an introduction to conceptual and technical aspects of (antievaporation effects, while discussing problems that are still open.
One-dimensional acoustic modeling of thermoacoustic instabilities (on cd)
van Kampen, J.F.; Huls, R.A.; Kok, Jacobus B.W.; van der Meer, Theodorus H.; Nilsson, A.; Boden, H.
2003-01-01
In this paper the acoustic stability of a premixed turbulent natural gas flame confined in a combustor is investigated. Specifically when the flame is operated in a lean premixed mode, the thermoacoustic system is known to exhibit instabilities. These arise from a feedback mechanism between the
Diffusive instability of a kaon condensate in neutron star matter
International Nuclear Information System (INIS)
Kubis, Sebastian
2004-01-01
The beta equilibrated dense matter with kaon condensate is analyzed with respect to extended stability conditions, including charge fluctuations. This kind of the diffusive instability appeared to be common property in the kaon condensation case. Results for three different nuclear models are presented
Ion-Beam-Excited Electrostatic Ion Cyclotron Instability
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1977-01-01
The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....
Ion-Beam-Excited, Electrostatic, Ion Cyclotron Instability
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1977-01-01
The stability limits of the ion‐beam‐excited, electrostatic, ion cyclotron instability were investigated in a Q‐machine plasma where the electrons could be heated by microwaves. In agreement with theory, the beam energy necessary for excitation decreased with increasing electron temperature....
Coupled-Beam and Coupled-Bunch Instabilities
Energy Technology Data Exchange (ETDEWEB)
Burov, Alexey [Fermilab
2016-06-23
A problem of coupled-beam instability is solved for two multibunch beams with slightly different revolution frequencies, as in the Fermilab Recycler Ring (RR). Sharing of the inter-bunch growth rates between the intra-bunch modes is described. The general analysis is applied to the RR; possibilities to stabilize the beams by means of chromaticity, feedback and Landau damping are considered.
The Fiscal Framework in a Currency Union
DEFF Research Database (Denmark)
Hallett, Andrew Hughes; Hougaard Jensen, Svend E.
2016-01-01
This paper draws out lessons from the euro area (EA) that are transferable to the Eastern Caribbean Currency Union (ECCU) and other Caribbean economies with fixed exchange rates. Based on observations from both the EA and the ECCU, we present a new policy framework which is capable of imposing...... fiscal discipline, with the aim of avoiding the risk of unsustainable fiscal policies reappearing and of preventing monetary policy from being undermined by undisciplined national governments. In the ECCU case, we find that fiscal deficits are more a result of financial and trade imbalances than fiscal...
Fiscal options for America's best hospitals.
Weil, T P; Pearl, G M
2001-06-01
A review of America's "best" teaching hospitals shows a huge disparity in their fiscal positions. Among the 15 hospitals studied, roughly half experience some fiscal distress. However, a somewhat similar fiscal analysis of the nation's largest investor-owned hospital chains, HMOs, and physician practice management corporations shows an even more serious weakness in operating margins and debt-equity ratios. Aside from raising possible ethical, quality, and cost issues, this financial analysis suggests that conversion from nonprofit to for-profit ownership of America's top teaching hospitals might not guarantee an improvement in their long-term fiscal outlook.
Secondary Instability of Second Modes in Hypersonic Boundary Layers
Li, Fei; Choudhari, Meelan M.; Chang, Chau-Lyan; White, Jeffery A.
2012-01-01
Second mode disturbances dominate the primary instability stage of transition in a number of hypersonic flow configurations. The highest amplification rates of second mode disturbances are usually associated with 2D (or axisymmetric) perturbations and, therefore, a likely scenario for the onset of the three-dimensionality required for laminar-turbulent transition corresponds to the parametric amplification of 3D secondary instabilities in the presence of 2D, finite amplitude second mode disturbances. The secondary instability of second mode disturbances is studied for selected canonical flow configurations. The basic state for the secondary instability analysis is obtained by tracking the linear and nonlinear evolution of 2D, second mode disturbances using nonlinear parabolized stability equations. Unlike in previous studies, the selection of primary disturbances used for the secondary instability analysis was based on their potential relevance to transition in a low disturbance environment and the effects of nonlinearity on the evolution of primary disturbances was accounted for. Strongly nonlinear effects related to the self-interaction of second mode disturbances lead to an upstream shift in the upper branch neutral location. Secondary instability computations confirm the previously known dominance of subharmonic modes at relatively small primary amplitudes. However, for the Purdue Mach 6 compression cone configuration, it was shown that a strong fundamental secondary instability can exist for a range of initial amplitudes of the most amplified second mode disturbance, indicating that the exclusive focus on subharmonic modes in the previous applications of secondary instability theory to second mode primary instability may not have been fully justified.
Concorrência fiscal prejudicial
Mendes, Narciso Manuel Marques
2011-01-01
Mestrado em Fiscalidade A crescente mobilidade de pessoas e capitais, e o desenvolvimento e utilização das novas tecnologias conduziram ao fenómeno da globalização da economia, do qual resultou um forte aumento da concorrência fiscal entre países. O fenómeno da concorrência fiscal deve, por si só, ser considerado como positivo, uma vez que beneficia os cidadãos e impõe uma pressão no sentido da redução das despesas públicas ao Estado. Contudo, uma concorrência ilimitada poderá tornar os si...
National Research Council Canada - National Science Library
Serafino, Nina M
2009-01-01
.... In September 2008, Congress passed the Reconstruction and Stabilization Civilian Management Act, 2008, as Title XVI of the Duncan Hunter National Defense Authorization Act for Fiscal Year 2009 (S. 3001, P.L...
Laminar Boundary-Layer Instabilities on Hypersonic Cones: Computations for Benchmark Experiments
National Research Council Canada - National Science Library
Robarge, Tyler W; Schneider, Steven P
2005-01-01
.... The STABL code package and its PSE-Chem stability solver are used to compute first and second mode instabilities for both sharp and blunt cones at wind tunnel conditions, with laminar mean flows...
Nonlinear Rayleigh–Taylor instability of the cylindrical fluid flow with ...
Indian Academy of Sciences (India)
2016-07-07
–Helmholtz instability problems in plane geometry. The linear stability analy- sis of a liquid–vapour interface (liquid as viscous and motionless and vapour as inviscid) moving with a hori- zontal velocity is studied in [5].
Effects of mass transfer on a resonance instability in the laminar ...
Indian Academy of Sciences (India)
pressible boundary layer flow due to a rotating-disk is investigated in this paper based on the linear stability theory. The possible .... Reynolds number limit to the inviscid modes strongly suggests that the resonance instability identified here ...
Squire, Jonathan; Hopkins, Philip F.
2018-04-01
We identify and study a number of new, rapidly growing instabilities of dust grains in protoplanetary disks, which may be important for planetesimal formation. The study is based on the recognition that dust-gas mixtures are generically unstable to a Resonant Drag Instability (RDI), whenever the gas, absent dust, supports undamped linear modes. We show that the "streaming instability" is an RDI associated with epicyclic oscillations; this provides simple interpretations for its mechanisms and accurate analytic expressions for its growth rates and fastest-growing wavelengths. We extend this analysis to more general dust streaming motions and other waves, including buoyancy and magnetohydrodynamic oscillations, finding various new instabilities. Most importantly, we identify the disk "settling instability," which occurs as dust settles vertically into the midplane of a rotating disk. For small grains, this instability grows many orders of magnitude faster than the standard streaming instability, with a growth rate that is independent of grain size. Growth timescales for realistic dust-to-gas ratios are comparable to the disk orbital period, and the characteristic wavelengths are more than an order of magnitude larger than the streaming instability (allowing the instability to concentrate larger masses). This suggests that in the process of settling, dust will band into rings then filaments or clumps, potentially seeding dust traps, high-metallicity regions that in turn seed the streaming instability, or even overdensities that coagulate or directly collapse to planetesimals.
THE STRUCTURAL DEFICIT – A NEW MEASURE FOR FISCAL DISCIPLINE IN THE EURO AREA
Directory of Open Access Journals (Sweden)
Cristina PUIU
2013-12-01
Full Text Available The aim of this paper is to assess the importance of the new limit for the government deficit in order to improve fiscal discipline in the Economic and Monetary Union in Europe. Since the introduction of the single currency there have been debates regarding the lack of fiscal integration. The monetary integration process triggered the centralization of monetary policies while the fiscal policies remained at national level. Although the member states of the euro area were subject to restrictions imposed by the Stability and Growth Pact in order to provide an assurance against asymmetric shocks, the recent financial crisis revealed high levels of public deficits. Thus, the measures were not enough to establish an environment of fiscal discipline in the currency area and the currency area proved to be suboptimal. Therefore, new limits were imposed through the Treaty of Stability, Coordination and Governance in the Economic and Monetary Union. This study will provide a clear understanding of the concept of structural deficit, measures used to quantify it and the shortcomings of this indicator. Furthermore, it will show that, despite the limits of the indicator, it represents an improvement in achieving stability in the euro area.
FINANCIAL INSTABILITY IN ROMANIA
Directory of Open Access Journals (Sweden)
Cristian, IONESCU
2014-11-01
Full Text Available The aim of this paper is to empirically study the concept of financial stability in Romania, from both a monetary policy perspective and a financial perspective. In this paper, I also compute an aggregate index of financial stability, for the period 2008-2013, explaining the correlations between several extremely important macroeconomic and sectorial variables and financial stability. The article also debates the aspect of policy instruments that aim to promote, highlighting the undertaken measures and also giving some measures recommendations, pointing out the main pillars: crises management; cross-sectoral challenges; banking sector; securities markets and capital markets; insurance sector; pensions sector; access to financial services.
Fiscal competition and regional differentiation
Justman, Moshe; Thisse, Jacques-François; Van Ypersele, Tanguy
2001-01-01
Regions can benefit by offering infrastructure services that are differentiated. Competition between regions over potential investors is then less direct, allowing them to realize greater benefits from external investors. The two polar cases of full and incomplete information about investors' needs are studied. In both cases, there is regional differentiation. However, fiscal competition is efficient in the former case but not in the latter. Finally, it is shown that free entry in the loc...
Marks on the petroleum fiscality
International Nuclear Information System (INIS)
2007-02-01
This document offers some marks on the petroleum fiscality in France: the taxes as the 'accises' and the 'TVA', the part of the taxes in the sale price at the service station, the comparison with other countries of Europe, the tax revenues and the Government budget. It provides also marks on the fuels prices formation (margins), the world petroleum markets (supply and demand) and the part of the petroleum companies on the petroleum market. (A.L.B.)
Thermal Shrinkage for Shoulder Instability
Toth, Alison P.; Warren, Russell F.; Petrigliano, Frank A.; Doward, David A.; Cordasco, Frank A.; Altchek, David W.; O’Brien, Stephen J.
2010-01-01
Thermal capsular shrinkage was popular for the treatment of shoulder instability, despite a paucity of outcomes data in the literature defining the indications for this procedure or supporting its long-term efficacy. The purpose of this study was to perform a clinical evaluation of radiofrequency thermal capsular shrinkage for the treatment of shoulder instability, with a minimum 2-year follow-up. From 1999 to 2001, 101 consecutive patients with mild to moderate shoulder instability underwent...
Political Instability and Economic Growth
Alberto Alesina; Sule Ozler; Nouriel Roubini; Phillip Swagel
1992-01-01
This paper investigates the relationship between political instability and per capita GDP growth in a sample of 113 countries for the period 1950-1982. We define ?political instability? as the propensity of a government collapse, and we estimate a model in which political instability and economic growth are jointly determined. The main result of this paper is that in countries and time periods with a high propensity of government collapse, growth is significantly lower than otherwise. This ef...
Fingering instabilities in bacterial community phototaxis
Vps, Ritwika; Man Wah Chau, Rosanna; Casey Huang, Kerwyn; Gopinathan, Ajay
Synechocystis sp PCC 6803 is a phototactic cyanobacterium that moves directionally in response to a light source. During phototaxis, these bacterial communities show emergent spatial organisation resulting in the formation of finger-like projections at the propagating front. In this study, we propose an analytical model that elucidates the underlying physical mechanisms which give rise to these spatial patterns. We describe the migrating front during phototaxis as a one-dimensional curve by considering the effects of phototactic bias, diffusion and surface tension. By considering the propagating front as composed of perturbations to a flat solution and using linear stability analysis, we predict a critical bias above which the finger-like projections appear as instabilities. We also predict the wavelengths of the fastest growing mode and the critical mode above which the instabilities disappear. We validate our predictions through comparisons to experimental data obtained by analysing images of phototaxis in Synechocystis communities. Our model also predicts the observed loss of instabilities in taxd1 mutants (cells with inactive TaxD1, an important photoreceptor in finger formation), by considering diffusion in mutually perpendicular directions and a lower, negative bias.
Beam instability studies at the APS
International Nuclear Information System (INIS)
Teng, L.C.
1994-01-01
The Argonne Advanced Photon Source, APS (Fig. 1), is a 7-GeV positron storage ring with a circumference of 1104 m. It has a ''third generation, DBA or Chasman-Green'' lattice composed of 40 sectors each having a ∼6 m long zero-dispersion straight-section for accommodating insertion devices. Neighboring straight-sections are connected by a 360 degrees/40 = 9 degrees double-bend-achromatic bending section designed to produce the smallest emittance attainable with reasonable component parameter values and dynamic apertures. Thus, it is a very strongly focusing lattice with v x = 35.22 and v y = 14.30. The beam chamber of the storage ring including all rf, vacuum and photon beam components is designed to ensure that a beam current > 100 mA can be stably stored. We expect that the maximum stable beam current could be as high as 300 mA. This paper will give some details of the studies and computations to ensure the stability of such a beam. The discussions will be organized in the following three parts: Coupled-bunch instability caused by the higher-order modes (HOMs) of the rf cavities; Single-bunch instability due to the resistive wall impedance; and Single-bunch instability due to broadband impedances arising from beam chamber irregularities
Instabilities in mimetic matter perturbations
Energy Technology Data Exchange (ETDEWEB)
Firouzjahi, Hassan; Gorji, Mohammad Ali [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Mansoori, Seyed Ali Hosseini, E-mail: firouz@ipm.ir, E-mail: gorji@ipm.ir, E-mail: shosseini@shahroodut.ac.ir, E-mail: shossein@ipm.ir [Physics Department, Shahrood University of Technology, P.O. Box 3619995161 Shahrood (Iran, Islamic Republic of)
2017-07-01
We study cosmological perturbations in mimetic matter scenario with a general higher derivative function. We calculate the quadratic action and show that both the kinetic term and the gradient term have the wrong sings. We perform the analysis in both comoving and Newtonian gauges and confirm that the Hamiltonians and the associated instabilities are consistent with each other in both gauges. The existence of instabilities is independent of the specific form of higher derivative function which generates gradients for mimetic field perturbations. It is verified that the ghost instability in mimetic perturbations is not associated with the higher derivative instabilities such as the Ostrogradsky ghost.
THE IMPACT OF MONETARY AND FISCAL POLICIES ON PUBLIC FINANCIAL MANAGEMENT
Directory of Open Access Journals (Sweden)
Loredana Ciurlău
2012-01-01
Full Text Available Fiscal policy is the main component of financial policy. Being a component of economic policy, taxation must lead to economic objectives. Maintaining equilibria macroeconomic cannot be blamed solely in charge of monetary policy, fiscal policy and that the revenue must have a role in support and to bear the load efforts to stabilise. Large deficits are dangerous for current account, because they are associated with a greater risk of producing an adjustment steep in the exchange rate and high volatility of exchange rate has major implications on the stability and macroeconomic monetary, in general. This means that countries should his election budgets so as to cope with growing demand from the private sector and to take necessary safeguard measures against potential crises, whereas the extent fiscal deficit contributes directly to the magnitude current account deficit.
Instability characteristics of fluidelastic instability of tube rows in crossflow
International Nuclear Information System (INIS)
Chen, S.S.; Jendrzejczyk, J.A.
1986-04-01
An experimental study is reported to investigate the jump phenomenon in critical flow velocities for tube rows with different pitch-to-diameter ratios and the excited and intrinsic instabilities for a tube row with a pitch-to-diameter ratio of 1.75. The experimental data provide additional insights into the instability phenomena of tube arrays in crossflow. 9 refs., 10 figs
Intrinsic stability of technical superconductors
International Nuclear Information System (INIS)
Veringa, H.J.
1981-10-01
For the operation of technical superconductors under high current density conditions, the superconducting wires composing high current cables should be intrinsically stabilized. In this report the various important stability criteria are derived and investigated on their validity. An experimental set up is made to check the occurrence of magnetic instabilities if the different applicable criteria are violated. It is found that the observed instabilities can be predicted on the basis of the model given in this report. Production of high current cables based upon composites made by the ECN technique seems to be possible. (Auth.)
Kinetic instabilities in relativistic plasmas: the Harris instability revisited
International Nuclear Information System (INIS)
Tautz, R.C.
2008-01-01
Plasma instabilities that generate aperiodic fluctuations are of outstanding importance in the astrophysical context. Two prominent examples are the electromagnetic Weibel instability and the electrostatic Harris instability, which operate in initially non-magnetized and magnetized plasmas, respectively. In this talk, the original formulation of the Harris instability will be reviewed and generalizations will be presented such as the inclusion of (1) relativistic effects, (2) ion effects, and (3) mode coupling. It will be shown that, with these modifications, a powerful method has been developed for the determination of both the existence and the growth rate of low-frequency instabilities. Applications can be found in astrophysical jets, where the rest frame can be used and so no parallel motion is present. At the end of the talk, how the particle composition of gamma-ray burst jets can be predicted using the Harris technique. (author)
Marquardt, Björn; Garmann, Stefan; Schulte, Tobias; Witt, Kai-Axel; Steinbeck, Jörn; Pötzl, Wolfgang
2007-01-01
The purpose of this study was to evaluate the incidence and reasons of recurrent instability in patients with traumatic anterior shoulder instability and to document the clinical results with regard to the number of stabilizing procedures. Twenty-four patients with failed primary open or arthroscopic anterior shoulder stabilization were followed for a mean of 68 (36-114) months. Following recurrence of shoulder instability, eight patients chose not to be operated on again, whereas 16 underwent repeat stabilization. A persistent or recurrent Bankart lesion was found in all 16 patients and concomitant capsular redundancy in 4. After the first revision surgery, further instability occurred in 8 patients, and 6 of them were stabilized a third time. Only 7 patients (29%) achieved a good or excellent result according to the Rowe score. All shoulder scores improved after revision stabilization. However, the number of stabilizing procedures adversely affected the outcome scores, as well as postoperative range of motion and patient satisfaction. Recurrent instability after a primary stabilization procedure represents a difficult diagnostic and surgical challenge, and careful attention should be paid to address persistent or recurrent Bankart lesions and concomitant capsular reduncancy. A satisfying functional outcome can be expected mainly in patients with one revision surgery. Further stabilization attempts are associated with poorer objective and subjective results.
Preventing Instability Phenomenon in Gas-lift Optimization
Directory of Open Access Journals (Sweden)
Mohammad Reza Mahdiani
2015-01-01
Full Text Available One of the problems that sometimes occur in gas allocation optimization is instability phenomenon. This phenomenon reduces the oil production and damages downhole and surface facilities. Different works have studied the stability and suggested some solutions to override it, but most of them (such as making the well intelligent are very expensive and thus they are not applicable to many cases. In this paper, as a new approach, the stability has been studied in gas allocation optimization problems. To prevent the instability, instability has been assumed as a constraint for the optimizer and then the optimizer has been run. For the optimization, first a genetic algorithm and then a hybrid of genetic algorithm and Newton-Quasi have been used, and their results are compared to ensure the good performance of the optimizer; afterwards, the effect of adding the instability constraint to the problem on production reduction have been discussed. The results show that the production loss with adding this constraint to the system is very small and this method does not need any additional and expensive facilities for preventing the instability. Therefore, the new method is applicable to different problems.
BWR regional instability model and verification on ringhals-1 test
International Nuclear Information System (INIS)
Hotta, Akitoshi; Suzawa, Yojiro
1996-01-01
Regional instability is known as one type of the coupled neutronic-thermohydraulic phenomena of boiling water reactors (BWRs), where the thermohydraulic density wave propagation mechanism is predominant. Historically, it has been simulated by the three-dimensional time domain code in spite of its significant computing time. On the other hand, there have been proposals to apply the frequency domain models in regional instability considering the subcriticality of the higher neutronic mode. However, their application still remains in corewide instability mainly because of the lack of more detailed methodological and empirical studies. In this study, the current version of the frequency domain model was extended and verified based on actual core regional instability measurement data. The mathematical model LAPUR, the well-known frequency domain stability code, was reviewed from the standpoint of pure thermohydraulics and neutronic-thermohydraulic interaction mechanisms. Based on the ex-core loop test data, the original LAPUR mixed friction and local pressure loss model was modified, taking into account the different dynamic behavior of these two pressure-loss mechanisms. The perturbation term of the two-phase friction multiplier, which is the sum of the derivative of void fraction and subcool enthalpy, was adjusted theoretically. The adequacy of the instability evaluation system was verified based on the Ringhals unit 1 test data, which were supplied to participants of the Organization for Economic Cooperation and Development/Nuclear Energy Agency BWR Stability Benchmark Project
Strategic interaction between fiscal and monetary policies in an export-oriented economy
Directory of Open Access Journals (Sweden)
Merzlyakov Sergey
2012-01-01
Full Text Available Solving the problem of stabilizing the economy is directly tied to the necessity of keeping the main macroeconomic variables stable. However, macroeconomic stability is not in the general case a purely fiscal or a purely monetary problem. How the central bank and the government interact is of principle importance. We investigate the impact of macroeconomic policies on the dynamics of the exchange rate, inflation, output and stabilization fund and consider different forms of strategic interaction between the government and the central bank. In this paper we build a stylized model of an export-oriented economy. We use numerical examples for our analysis and practical conclusions. The effective interaction of fiscal and monetary policies is possible under a cooperative Stackelberg game interaction with the government as leader. It is shown that the independence of the central bank does not play a crucial role.
Bunched beam longitudinal stability
International Nuclear Information System (INIS)
Baartman, R.
1991-05-01
Instabilities driven by narrow-band impedances can be stabilized by Landau damping arising from the synchrotron frequency spread due to the nonlinearity of the rf wave-form. We calculate stability diagrams for various phase space distributions. We find that distributions without tails are unstable in the 'negative mass' regime (inductive impedance below transition or capacitive impedance above transition). We also find that longitudinal instability thresholds of the (usually neglected) higher order radial modes are lower than expected. For example, the next to lowest dipole mode has a lower threshold than the lowest sextupole mode even though the latter has the larger growth rate in the absence of Landau damping. (Author) 5 refs., 5 figs
Sovereign default and the stability of inflation targeting regimes
Schabert, A.; van Wijnbergen, S.J.G.
2011-01-01
We analyse the impact of interactions between monetary and fiscal policy on macroeconomic stability. We find that in the presence of sovereign default beliefs a monetary policy, which aims to stabilize inflation through an active interest rate policy, will destabilize the economy if the feedback
Financial stability in the eurozone : Where do we stand?
Arnold, I.J.M.
2007-01-01
At the start of the EMU, concerns about fiscal and monetary stability dominated the academic debate. In contrast, financial stability issues were largely overlooked. Since then, more attention has been paid to the implications of the EMU for financial regulation and supervision and to the drawbacks
Out-of-phase flashing induced instabilities in CIRCUS facility
Energy Technology Data Exchange (ETDEWEB)
Christian Pablo Marcel; Van der Hagen, T.H.J.J. [Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)
2005-07-01
Full text of publication follows: Flashing-induced instabilities are very important during the startup phase of natural-circulation boiling water reactors. To study this type of instability an axial fully scaled facility named CIRCUS was constructed. Experiments at low power and low pressure (typical startup conditions) are carried out on this steam/water natural circulation loop with two parallel risers. A detailed measurement of the void-fraction profile is possible by using needle-probes and the use of glass tubes for the riser and core sections allow to use optical techniques for velocity measurements. The flashing and the mechanism of flashing-induced instabilities are analyzed paying special attention on the strong coupling effect between the two riser channels. It is clear from the experiments that the out-of-phase instability is much more susceptible to occur than the in-phase instability in a system with two parallel risers. The instability region is found as soon as the operational boundary between single-phase and two-phase operation is crossed. The relation between the period of the oscillations and the fluid transient time is also investigated. The stability map constructed using this experimental data is also discussed. (authors)
24 CFR 968.145 - Fiscal closeout.
2010-04-01
... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Fiscal closeout. 968.145 Section... PUBLIC HOUSING MODERNIZATION General § 968.145 Fiscal closeout. (a) Actual modernization cost certificate... for audit. After audit verification, HUD shall approve the AMCC. (b) Audit. The audit shall follow the...
Fiscal Transparency, Elections and Public Employment
DEFF Research Database (Denmark)
Aaskoven, Lasse
2016-01-01
There is considerable variation in levels and changes in public employment within and between developed democracies. This article highlights the importance of fiscal transparency in determining changes in public employment. It argues that economic growth increases public employment under low fiscal...
13 CFR 120.952 - Fiscal agent.
2010-01-01
... Fiscal Agent to assess the financial markets, minimize the cost of sales, arrange for the production of... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Fiscal agent. 120.952 Section 120.952 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Development Company...
42 CFR 54.10 - Fiscal accountability.
2010-10-01
... 42 Public Health 1 2010-10-01 2010-10-01 false Fiscal accountability. 54.10 Section 54.10 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS CHARITABLE CHOICE... PROJECTS FOR ASSISTANCE IN TRANSITION FROM HOMELESSNESS GRANTS § 54.10 Fiscal accountability. (a) Religious...
42 CFR 54a.10 - Fiscal accountability.
2010-10-01
... 42 Public Health 1 2010-10-01 2010-10-01 false Fiscal accountability. 54a.10 Section 54a.10 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS CHARITABLE CHOICE... PREVENTION AND TREATMENT SERVICES § 54a.10 Fiscal accountability. (a) Religious organizations that receive...
Defense.gov Special Report: Fiscal Budget
Department of Defense Submit Search 2012 Fiscal Budget Published Feb. 15, 2011 Top Stories Commanders Cite Department is losing billions of dollars by Congress' failure to pass the department's fiscal 2011 budget . Gates told a Senate committee. Story Gates, Mullen Take Budget to Senate WASHINGTON, Feb. 17, 2011 - The
European Fiscal Policy of Tax Havens
Directory of Open Access Journals (Sweden)
Gabriela Mironov
2009-10-01
Full Text Available Taxation system is a necessary evil. Almost the entire world admits its utility, but even necessary as it is, the taxation system remains an evil. Fiscal paradises had been born heavily, but they multiplied quickly. In specialization literature, as well as in juridical and economical literature there are few and modest attempts of analysis of fiscal paradises, although a circumscribing of the area that is covered is not difficult to realize. Every state can be used as fiscal paradises for certain persons on the basis of several taxation agreements that provide an auspicious system for certain types of incomes and investments performed by foreigners in the respective country. There is a multitude of possibilities for the decrease of fiscal overwhelming. A legal possibility is the fiscal scheduling using the offshore companies registered in jurisdictions with fiscal paradise status. Fiscal scheduling through offshore company means the election of that type of company that fits for the purpose and interests of the business. There is also the problem of the election of the best jurisdiction in concordance with the purpose pursued. Fiscal paradises represent the fertile ground for the manipulation of taxation basis of the benefits, through utilization of intermediate transfer prices, having as justifiable basis economical transactions, most of the times simulated transactions. The legality, but most of all the ethics of the techniques used are al least controversial.
31 CFR 352.13 - Fiscal agents.
2010-07-01
... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 352.13 Section 352.13 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... Reserve Bank of Kansas City, 925 Grand Avenue, Kansas City, MO 64198 Dallas, San Francisco, Kansas City...
31 CFR 316.12 - Fiscal agents.
2010-07-01
... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 316.12 Section 316.12 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE..., Kansas City, MO 64198 Dallas, San Francisco, Kansas City, St. Louis AK, AR, AZ, CA, CO, HI, ID, IL...
2010-07-01
... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 330.9 Section 330.9 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE.... Federal Reserve Bank of Kansas City, 925 Grand Avenue, Kansas City, MO 64198 Dallas, San Francisco, Kansas...
31 CFR 332.12 - Fiscal agents.
2010-07-01
... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 332.12 Section 332.12 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... City, 925 Grand Avenue, Kansas City, MO 64198 Dallas, San Francisco, Kansas City, St. Louis AK, AR, AZ...
2010-07-01
... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 342.9 Section 342.9 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... Avenue, Kansas City, MO 64198 Dallas, San Francisco, Kansas City, St. Louis AK, AR, AZ, CA, CO, HI, ID...
Money Market Operations in Fiscal 2007
Financial Markets Department
2008-01-01
Throughout fiscal 2007, the Bank of Japan conducted money market operations with the uncollateralized overnight call rate as the operating target. The target level for the uncollateralized overnight call rate remained at "around 0.5 percent" throughout all of fiscal 2007. During this period, the basic loan rate applied to the complementary lending facility was 0.75 percent.
International Nuclear Information System (INIS)
Hiranuma, Yasunari; Atsumi, Takashi; Kajiwara, Toshihisa; Tamaoki, Satoshi; Asakura, Yasuhiro
2009-01-01
Transtrochanteric anterior rotational osteotomy results in improvement of joint congruity and prevention of progressive collapse and osteoarthritic changes in patients with femoral head osteonecrosis. However, this procedure remains controversial for patients with extensive collapse due to potential osteoarthritis caused by postoperative instability. The purpose of this study was to evaluate hip instability after osteotomy and determine the relation between instability and radiological and clinical outcomes. In all, 27 hips of 24 patients that were followed up for a mean period of 3.8 years were included. Instability was defined as more than 1 mm translation of the femoral head in transverse computed tomography scans obtained at 0 deg and 45 deg flexion of the hip joint. Hips were divided into instability and stability groups. Eleven hips (40%) developed instability after surgery. Osteophytes on the femoral head in 10 hips of the instability group and 2 hips of the stability group had increased in size at follow-up. There was a significant relation between postoperative instability and osteophyte formation. Joint space narrowing was not seen in any of the cases. There was no significant difference between the groups in either the postoperative intact ratio of the femoral head or the Japanese Orthopaedic Association hip score. Neither instability nor osteophyte formation on the femoral head after transtrochanteric anterior rotational osteotomy correlated with progressive osteoarthritic changes or clinical outcome in the presence of an adequate femoral head intact ratio facing the weight-bearing area. (author)
An analysis for crack layer stability
Sehanobish, K.; Botsis, J.; Moet, A.; Chudnovsky, A.
1986-01-01
The problem of uncontrolled crack propagation and crack arrest is considered with respect to crack layer (CL) translational stability. CL propagation is determined by the difference between the energy release rate and the amount of energy required for material transformation, and necessary and sufficient conditions for CL instability are derived. CL propagation in polystyrene is studied for two cases. For the case of remotely applied fixed load fatigue, the sufficient condition of instability is shown to be met before the necessary condition, and the necessary condition controls the stability. For the fixed displacement case, neither of the instability conditions are met, and CL propagation remains stable, resulting in crack arrest.
THE EVOLUTION OF FISCAL INDICATORS IN THE LAST YEARSIN ROMANIA
Directory of Open Access Journals (Sweden)
Kulcsar Edina
2011-07-01
Full Text Available Tax revenues are an important part of budget revenues, and their structure represent the mirror of government's fiscal policy. Also their level and structure reflects the evolution of the economy in general. The evolution of tax revenues has been influenced by the financial crisis of this period. The tax revenue structure in Romania is characterized by relatively high share of indirect taxes revenues in comparison with another European Union states, where the share of revenues from direct, indirect taxes and social contribution is relatively close. Government expenditure is vital for the economy especially if they are focused on productive areas. They are the engine of economic developments and plays an important role in raising the standard of living of population in a state. In the last years, the growth rate of public expenditure was higher than the trend of tax revenues increase. Sizing revenue and public expenditure is essential for achieving the budget balance target and to meet the criterion stipulated in the Stability and Growth Pact. According to the Pact, the budget deficit may not exceed 3% of GDP. This development asymmetric led to increased deficits in the last years. The high level of structural deficit has canceled an initiative to tax relaxation in this recession period. The need for fiscal consolidation has been paramount in the context of chronic deficit and difficulties faced in financing it. The opportune solution to finance the high public deficit and to achieve the objective of financial stability of the economy was contracting of public debt from International Monetary Fund. Other measures to reduce the deficit were the reduction of public expenditure and increasing tax revenues. We propose in this paper to analyze the evolution of fiscal indicators in comparison with the evolution of macroeconomic indicators to capture the reaction of taxpayers and economic environment at measures adopted.
Posterolateral elbow joint instability
DEFF Research Database (Denmark)
Olsen, Bo Sanderhoff; Søjbjerg, Jens Ole; Nielsen, K K
1998-01-01
Thirty-five osteoligamentous elbows were included in a study on the kinematics of posterolateral elbow joint instability during the pivot shift test (PST) before and after separate ligament cuttings in the lateral collateral ligament complex (LCLC). Division of the annular ligament or the lateral...... ulnar collateral ligament caused no laxity during the PST. Division of the lateral collateral ligament caused maximal laxity of 4 degrees and 23 degrees during forced PST in valgus and external rotation (supination), respectively. Cutting of the LCLC at the ulnar or the humeral insertion was necessary...... for any PST stressed elbow joint laxity to occur. Total division of the LCLC induced a maximal laxity of 7.9 degrees and 37 degrees during forced PST in valgus and external rotation (supination), respectively. This study suggests the lateral collateral ligament to be the primary soft tissue constraint...
From instabilities to multifragmentation
International Nuclear Information System (INIS)
Chomaz, P.; Jacquot, B.; Colonna, M.; Guarnera, A.
1994-01-01
The main purpose of this article is to show that, in many physical situations, the spinodal decomposition of unstable systems can be correctly described by stochastic mean-field approaches. Such theories predict that the occurrence of spinodal instability leading the multifragmentation of an expended nuclear system, can be signed through the observation of time scales for the fragment formation of the order of 100 fm/c and of typical fragment size around A=20. We will finally discuss the fact that these fragments are formed at finite temperature and so can subsequently decay in flight. Finally, we will give some hints about possible experimental signals of such first order phase transitions. (authors). 12 refs., 5 figs
From instabilities to multifragmentation
Energy Technology Data Exchange (ETDEWEB)
Chomaz, P.; Jacquot, B. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France); Colonna, M.; Guarnera, A. [Grand Accelerateur National d`Ions Lourds (GANIL), 14 - Caen (France)]|[Istituto Nazionale di Fisica Nucleare, Bologna (Italy)
1994-12-31
The main purpose of this article is to show that, in many physical situations, the spinodal decomposition of unstable systems can be correctly described by stochastic mean-field approaches. Such theories predict that the occurrence of spinodal instability leading the multifragmentation of an expended nuclear system, can be signed through the observation of time scales for the fragment formation of the order of 100 fm/c and of typical fragment size around A=20. We will finally discuss the fact that these fragments are formed at finite temperature and so can subsequently decay in flight. Finally, we will give some hints about possible experimental signals of such first order phase transitions. (authors). 12 refs., 5 figs.
Investigation of global Alfven instabilities in TFTR
International Nuclear Information System (INIS)
Wong, K.L.; Paul, S.F.; Fredrickson, E.D.; Nazikian, R.; Park, H.K.; Bell, M.; Bretz, N.L.; Budny, R.; Cheng, C.Z.; Cohen, S.; Hammett, G.W.; Jobes, F.C.; Johnson, L.; Meade, D.M.; Medley, S.S.; Mueller, D.; Nagayama, Y.; Owens, D.K.; Synakowski, E.J.; Roberts, D.R.; Sabbagh, S.
1992-01-01
Toroidal Alfven Eigenmodes (TAE) were excited by the energetic neutral beam ions tangentially injected into TFTR plasmas at low magnetic field such that the injection velocities were comparable to the Alfven speed. The modes were identified by measurements from Mirnov coils and beam emission spectroscopy (BES). TAE modes appear in bursts whose repetition rate increases with beam power. The neutron emission rate exhibits sawtooth-like behavior and the crashes always coincide with TAE bursts. This indicates ejection of fast ions from the plasma until these modes are stabilized. The dynamics of growth and stabilization was investigated at various plasma current and magnetic field. The results indicate that the instability can effectively clamp the number of energetic ions in the plasma. The observed instability threshold is discussed in the light of recent theories. In addition to these TAE modes, intermittent oscillations at three times the fundamental TAE frequency were observed by Mirnov coils, but no corresponding signal was found in BES. It appears that these high frequency oscillations do not have direct effect on the plasma neutron source strength
Saturation of equatorial inertial instability
Kloosterziel, R.C.; Orlandi, P.; Carnevale, G.F.
2015-01-01
Inertial instability in parallel shear flows and circular vortices in a uniformly rotating system ( $f$f-plane) redistributes absolute linear momentum or absolute angular momentum in such a way as to neutralize the instability. In previous studies we showed that, in the absence of other
Numerical modeling of flow boiling instabilities using TRACE
International Nuclear Information System (INIS)
Kommer, Eric M.
2015-01-01
Highlights: • TRACE was used to realistically model boiling instabilities in single and parallel channel configurations. • Model parameters were chosen to exactly mimic other author’s work in order to provide for direct comparison of results. • Flow stability maps generated by the model show unstable flow at operating points similar to other authors. • The method of adjudicating when a flow is “unstable” is critical in this type of numerical study. - Abstract: Dynamic flow instabilities in two-phase systems are a vitally important area of study due to their effects on a great number of industrial applications, including heat exchangers in nuclear power plants. Several next generation nuclear reactor designs incorporate once through steam generators which will exhibit boiling flow instabilities if not properly designed or when operated outside design limits. A number of numerical thermal hydraulic codes attempt to model instabilities for initial design and for use in accident analysis. TRACE, the Nuclear Regulatory Commission’s newest thermal hydraulic code is used in this study to investigate flow instabilities in both single and dual parallel channel configurations. The model parameters are selected as to replicate other investigators’ experimental and numerical work in order to provide easy comparison. Particular attention is paid to the similarities between analysis using TRACE Version 5.0 and RELAP5/MOD3.3. Comparison of results is accomplished via flow stability maps non-dimensionalized via the phase change and subcooling numbers. Results of this study show that TRACE does indeed model two phase flow instabilities, with the transient response closely mimicking that seen in experimental studies. When compared to flow stability maps generated using RELAP, TRACE shows similar results with differences likely due to the somewhat qualitative criteria used by various authors to determine when the flow is truly unstable
Positional instability analysis of tokamak plasmas by ERATO
International Nuclear Information System (INIS)
Kumagai, Michikazu; Tsunematsu, Toshihide; Tokuda, Shinji; Takeda, Tatsuoki
1983-06-01
The stability of axisymmetric modes of a tokamak plasma(positional instabilities) is analyzed for the Solov'ev equilibrium by using the linear ideal MHD code ERATO-J. The dependence of the stability on various parameters, i.e., the ellipticity and triangularity of the plasma cross-section, the aspect ratio, the safety factor at the magnetic axis, and the distance between the plasma and a conducting shell is investigated. Comparison of the results with those by the rigid model shows that the stability condition derived from the rigid model in terms of the decay index(n-index) of the external equilibrating field is a good approximation for the plasma with small triangular deformation. Also the results are compared with those of the rigid displacement model and applicability of the various models on the positional instability analyses is discussed. (author)
Do Municipal Mergers Improve Fiscal Outcomes?
DEFF Research Database (Denmark)
Hansen, Sune Welling; Houlberg, Kurt; Holm Pedersen, Lene
2014-01-01
Improved fiscal management is a frequent justification for promoting boundary consolidations. However, whether or not this is actually the case is rarely placed under rigorous empirical scrutiny. Hence, this article investigates if fiscal outcomes are improved when municipalities are merged....... The basic argument is that the conceptualisation of fiscal management in political science is often too narrow as it focuses on the budget and pays hardly any attention to balances in the final accounts and debts – elements of management which are central to policy making. On this background, the causal...... relationship between municipal mergers and fiscal outcomes is analysed. Measured on the balance between revenues and expenses, liquid assets and debts, municipal mergers improve the fiscal outcomes of the municipalities in a five-year perspective, although the pre-reform effects tend to be negative...
Dynamical Instability and Soliton Concept
International Nuclear Information System (INIS)
Kartavenko, V.G.
1994-01-01
The problem of dynamical instability and clustering (stable fragments formation) in a breakup of excited nuclear systems are considered from the points of view of the soliton concept. It is noted that the volume (spinodal) instability can be associated with nonlinear terms, and the surface (Rayleigh-Taylor type) instability, with the dispersion terms in the evolution equations. The spinodal instability and the Rayleigh-Taylor instability may compensate each other and lead to stable quasi-soliton type objects. The simple analytical model is presented to illustrate this physical picture. The time evolution of an initially compressed cold nuclear system is analysed in the framework of the inverse mean-field method. It is demonstrated that the nonlinearity and dispersion terms of the evolution equations can lead to clusterization in the final channel. 8 p
Beam instability Workshop - plenary sessions
International Nuclear Information System (INIS)
2001-01-01
The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions
Beam instability Workshop - plenary sessions
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-07-01
The purpose of this workshop was to provide a review of the mechanisms of limiting beam instabilities, their cures, including feedback, and beam measurement for synchrotron radiation light sources. 12 plenary sessions took place whose titles are: 1) challenging brilliance and lifetime issues with increasing currents; 2) limiting instabilities in multibunch; 3) experience from high currents in B factories; 4) longitudinal dynamics in high intensity/bunch; 5) Transverse instabilities for high intensity/bunch; 6) working group introduction from ESRF experience; 7) impedance modelling: simulations, minimization; 8) report on the broadband impedance measurements and modelling workshop; 9) feedback systems for synchrotron light sources; 10) beam instabilities diagnostics; 11) harmonic cavities: the pros and cons; and 12) experimental study of fast beam-ion instabilities at PLS. This document gathers the 12 articles that were presented during these sessions.
Electron/electron acoustic instability
International Nuclear Information System (INIS)
Gary, S.P.
1987-01-01
The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma
Tertiary instability of zonal flows within the Wigner-Moyal formulation of drift turbulence
Zhu, Hongxuan; Ruiz, D. E.; Dodin, I. Y.
2017-10-01
The stability of zonal flows (ZFs) is analyzed within the generalized-Hasegawa-Mima model. The necessary and sufficient condition for a ZF instability, which is also known as the tertiary instability, is identified. The qualitative physics behind the tertiary instability is explained using the recently developed Wigner-Moyal formulation and the corresponding wave kinetic equation (WKE) in the geometrical-optics (GO) limit. By analyzing the drifton phase space trajectories, we find that the corrections proposed in Ref. to the WKE are critical for capturing the spatial scales characteristic for the tertiary instability. That said, we also find that this instability itself cannot be adequately described within a GO formulation in principle. Using the Wigner-Moyal equations, which capture diffraction, we analytically derive the tertiary-instability growth rate and compare it with numerical simulations. The research was sponsored by the U.S. Department of Energy.
International Nuclear Information System (INIS)
Gleiser, M.
1988-01-01
Boson stars are gravitationally bound, spherically symmetric equilibrium configurations of cold, free, or interacting complex scalar fields phi. As these equilibrium configurations naturally present local anisotropy, it is sensible to expect departures from the well-known stability criteria for fluid stars. With this in mind, I investigate the dynamical instability of boson stars against charge-conserving, small radial perturbations. Following the method developed by Chandrasekhar, a variational base for determining the eigenfrequencies of the perturbations is found. This approach allows one to find numerically an upper bound for the central density where dynamical instability occurs. As applications of the formalism, I study the stability of equilibrium configurations obtained both for the free and for the self-interacting [with V(phi) = (λ/4)chemical bondphichemical bond 4 ] massive scalar field phi. Instabilities are found to occur not for the critical central density as in fluid stars but for central densities considerably higher. The departure from the results for fluid stars is sensitive to the coupling λ; the higher the value of λ, the more the stability properties of boson stars approach those of a fluid star. These results are linked to the fractional anisotropy at the radius of the configuration
Fiscal transparency, political parties, and debt in OECD countries
DEFF Research Database (Denmark)
Alt, James E.; Lassen, David Dreyer
2006-01-01
Many believe and argue that fiscal, or budgetary, transparency has large, positive effects on fiscal performance. However, the evidence linking transparency and fiscal policy outcomes is less compelling. To analyze the effects of fiscal transparency on public debt accumulation, we present a career...
What are the Effects of Fiscal Policy Shocks?
Mountford, A.W.; Uhlig, H.F.H.V.S.
2002-01-01
We investigate the effects of fiscal policy surprises for US data, using vector autoregressions.We overcome the difficulties that changes in fiscal policy may manifest themselves in variables other than fiscal variables first and that fiscal variables may respond 'automatically' to business cycle
Gravitational Instabilities in Circumstellar Disks
Kratter, Kaitlin; Lodato, Giuseppe
2016-09-01
Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular
Jeans instability with exchange effects in quantum dusty magnetoplasmas
International Nuclear Information System (INIS)
Jamil, M.; Rasheed, A.; Rozina, Ch.; Jung, Y.-D.; Salimullah, M.
2015-01-01
Jeans instability is examined in magnetized quantum dusty plasmas using the quantum hydrodynamic model. The quantum effects are considered via exchange-correlation potential, recoil effect, and Fermi degenerate pressure, in addition to thermal effects of plasma species. It is found that the electron exchange and correlation potential have significant effects over the threshold value of wave vector and Jeans instability. The presence of electron exchange and correlation effect shortens the time of dust sound that comparatively stabilizes the self gravitational collapse. The results at quantum scale are helpful in understanding the collapse of the self-gravitating dusty plasma systems
Modulational instability and the Fermi-Pasta-Ulam recurrence
International Nuclear Information System (INIS)
Janssen, P.A.E.M.
1981-01-01
The long-time behavior of the modulational instability of the nonlinear Schroedinger equation is investigated. Linear stability analysis shows that a finite amplitude uniform wave train is unstable to infinitesimal modulational perturbations with sufficiently long wavelengths while it is stable for perturbations with short wavelengths. Near the threshold for instability, the long-time behavior of the unstable modulation is obtained by means of the multiple time scale technique. As a result, the Fermi--Pasta--Ulam recurrence is rediscovered, in agreement with recent experiments and with a numerical solution of the problem at hand
Refinements to longitudinal, single bunch, coherent instability theory
Energy Technology Data Exchange (ETDEWEB)
Koscielniak, S R
1995-06-01
For the case of a bunched beam confined to a quadratic potential well, we demonstrate the necessity for considering mode-coupling to correctly obtain the threshold current for the d.c. instability. Further we find the effect upon growth rate and coherent tune shift of evaluating the impedance at a complex frequency. For the case of a bunched beam confined to a cosine potential well, we give an exact analytic expression for the dispersion integral, and calculate (with no approximations), the stability diagram for the Robinson instability taking into account Landau damping. This paper comprises extracts from a lengthy internal report. (author). 2 refs., 4 figs.
Secondary Instabilities and Spatiotemporal Chaos in Parametric Surface Waves
International Nuclear Information System (INIS)
Zhang, W.; Vinals, J.
1995-01-01
A 2D model is introduced to study the onset of parametric surface waves, their secondary instabilities, and the transition to spatiotemporal chaos. We obtain the stability boundary of a periodic standing wave above onset against Eckhaus, zigzag, and transverse amplitude modulations (TAM), as a function of the control parameter var-epsilon and the wavelength of the pattern. The Eckhaus and TAM boundaries cross at a finite value of var-epsilon, thus explaining the finite threshold for the TAM observed experimentally. At larger values of var-epsilon, a numerical solution reveals a transition to spatiotemporal chaotic states mediated by the TAM instability
Instability timescale for the inclination instability in the solar system
Zderic, Alexander; Madigan, Ann-Marie; Fleisig, Jacob
2018-04-01
The gravitational influence of small bodies is often neglected in the study of solar system dynamics. However, this is not always an appropriate assumption. For example, mutual secular torques between low mass particles on eccentric orbits can result in a self-gravity instability (`inclination instability'; Madigan & McCourt 2016). During the instability, inclinations increase exponentially, eccentricities decrease (detachment), and orbits cluster in argument of perihelion. In the solar system, the orbits of the most distant objects show all three of these characteristics (high inclination: Volk & Malhotra (2017), detachment: Delsanti & Jewitt (2006), and argument of perihelion clustering: Trujillo & Sheppard (2014)). The inclination instability is a natural explanation for these phenomena.Unfortunately, full N-body simulations of the solar system are unfeasible (N ≈ O(1012)), and the behavior of the instability depends on N, prohibiting the direct application of lower N simulations. Here we present the instability timescale's functional dependence on N, allowing us to extrapolate our simulation results to that appropriate for the solar system. We show that ~5 MEarth of small icy bodies in the Sedna region is sufficient for the inclination instability to occur in the outer solar system.
Territorial fiscal control. Diagnostic and outlook
Directory of Open Access Journals (Sweden)
Carlos Ariel Sanchez-Torres
2010-03-01
Full Text Available This document contains the research results of the territorial fiscal control improvement proposal project, developed by Rosario University with the support by the German Technical Cooperation Agency (GTZ. In short, it analyzes and identifies the principal problems of the Colombian territorial fiscal control system on the first level, (Contraloría General de la República Office, Departmental, Municipal and District Controller Offices offering a general view of the performance and the distribution of responsibilities between the different fiscal control bodies. The document is structured as follows: l introduction and constitutional scheme of the fiscal control system, 2 a description of the distribution of responsibilities between the different fiscal control bodies, 3 the development of territorial fiscal control with reference to jurisprudence, 4 territorial fiscal control, 5 quality of territorial fiscal control and 6 reform proposals and conclusions. Among the proposals analyzed in this project we have, the depoliticization on the election of the employees in charge of territorial fiscal control, the financing necessary to realize that control, sourced from territorial entities own resources and the achievement of economies of scale thought the merging of control bodies; Another proposal involves the integration of territorial fiscal control with the second level control by means of .the application of support mechanism to the control function exercise by Contraloría General de la República Office, and a improvement of information systems, indicators and evaluations applied by territorial controller offices.
Magnet stability and reproducibility
Marks, N
2010-01-01
Magnet stability and reproducibility have become increasingly important as greater precision and beams with smaller dimension are required for research, medical and other purpose. The observed causes of mechanical and electrical instability are introduced and the engineering arrangements needed to minimize these problems discussed; the resulting performance of a state-of-the-art synchrotron source (Diamond) is then presented. The need for orbit feedback to obtain best possible beam stability is briefly introduced, but omitting any details of the necessary technical equipment, which is outside the scope of the presentation.
Lutenegger, A.J.; Hallberg, G.R.
1988-01-01
Lutenegger, A.J. and Hallberg, G.R., 1988. Stability of loess. Eng. Geol., 25: 247-261. The natural stability of loess soils can be related to fundamental geotechnical properties such as Atterberg limits, water content and void ratio. Field observations of unstable conditions in loess deposits in the upper midwest, U.S.A. show relationships between instability and the in situ moisture content and the liquidity index of the loess. Unstable loess can attain natural moisture contents equal to, or greater than, its liquid limit. Implications of these observations for applied engineering works are described. ?? 1988.
Thermal instabilities in magnetically confined plasmas: Solar coronal loops
International Nuclear Information System (INIS)
Habbal, S.R.; Rosner, R.
1979-01-01
The thermal stability of confined solar coronal structures (''loops'') is investigated, following both normal mode and a new, global instability analysis. We demonstrate that: (a) normal mode analysis shows modes with size scales comparable to that of loops to be unstable, but to be strongly affected by the loop boundary conditions; (b) a global analysis, based upon variation of the total loop energy losses and gains, yields loop stability conditions for global modes dependent upon the coronal loop heating process, with magnetically coupled heating processes giving marginal stability. The connection between the present analysis and the minimum flux corona of Hearn is also discussed
Functional Instability of the Ankle Joint: Etiopathogenesis
Directory of Open Access Journals (Sweden)
Aydan ÖRSÇELİK
2016-09-01
Full Text Available Ankle sprain is one of the most common sports injuries. Chronic ankle instability is a common complication of ankle sprains. Two causes of chronic ankle instability are mechanical instability and functional instability. It is important to understand functional instability etiopathogenesis of the ankle joint in order to guide diagnosis and treatment. This article aims to understand the etiopathogenesis of functional ankle instability.
Reference data about petroleum fiscality
International Nuclear Information System (INIS)
2006-01-01
This paper explains the different taxes existing in France for the petroleum products (domestic tax on petroleum products, added-value tax), the share of taxes in the retail price, the differences with other European countries, the French Government fiscal receipts and budget. Some information forms are attached to this document and concern: the formation of fuel prices (upstream, refining and transport-distribution margins), the evolution of annual average transport-distribution margins, some reference data about world petroleum markets (supply and demand, prices, market data), and some reference data about the role of oil companies on the petroleum market. (J.S.)