Impulsive Character Research Articles

Dynamics of the energy intensity of the Russian economy in 2006–2007 and projections of the energy consumption

This paper is devoted to the analysis of the energy intensity in the sequential chain of hierarchically interconnected levels of the Russian Federation’s economy in 2006–2007, i.e., GDP segments of the economy’s technological processes sectors. In terms of the energy consumption projection, 2006 and 2007 present an extremely interesting example of the changing impulsive character of the growth of the demand for electric energy under intensively growing domestic and foreign demand for products of energy intensive sectors of the Russian Federation. The year of 2006 demonstrated a high growth of the per unit GDP and a very high growth of energy consumption under fast growing internal and external demand for energy intensive products; the year of 2007 showed a still higher growth of the GDP at a sharply curtailed growth of the energy consumption, and the rate of decline of the GDP energy intensity almost doubled. The comparative analysis of 2006 and 2007 can help one to understand what can underlie the changed energy consumption in the country in the period of the world crisis and after its end.

Simulating asymmetric colloidal mixture with adhesive hard sphere model

Monte Carlo simulation and Percus-Yevick (PY) theory are used to investigate the structural properties of a two-component system of the Baxter adhesive fluids with the size asymmetry of the particles of both components mimicking an asymmetric binary colloidal mixture. The radial distribution functions for all possible species pairs, g(11)(r), g(22)(r), and g(12)(r), exhibit discontinuities at the interparticle distances corresponding to certain combinations of n and m values (n and m being integers) in the sum nsigma(1)+msigma(2) (sigma(1) and sigma(2) being the hard-core diameters of individual components) as a consequence of the impulse character of 1-1, 2-2, and 1-2 attractive interactions. In contrast to the PY theory, which predicts the delta function peaks in the shape of g(ij)(r) only at the distances which are the multiple of the molecular sizes corresponding to different linear structures of successively connected particles, the simulation results reveal additional peaks at intermediate distances originating from the formation of rigid clusters of various geometries.

Helping Young Children to Delay Gratification

The ability to delay gratification (DG) in young children is vital to their later development. Such ability should be taught as early as possible. One hundred kindergartners (Mean age = 6.11), randomly assigned to three groups; a, labeling: received the treatment of being labeled as “patient” kids; b, story-telling: were read a story about the patient antagonist rewarded double gifts, while the impulsive character got only one same reward; c, control: received no treatment. Under the DG task of Ball-Moving Activity, the ANOVA results showed the children in labeling group delayed longer (M = 13.23 m) than the control one (M = 11.25 m), showed marginal significant difference at p = .06, medium effect size magnitude at η2 = .06. No significant mean differences were found between the story-telling (M = 12.68 m) and the control group, though the story-telling group delayed more than 1 min longer than their counterparts. Sex differences on the task are also discussed.

Evaluation of near-source seismic records based on damage potential parameters: Case study: Greece

The study presents the results of an investigation that identifies among the available records in Greece those that reveal near-source characteristics, using a procedure based on damage potential parameters. The findings reaffirm the opinion that earthquakes with magnitude less than M=6.0 present near-source phenomena that can cause severe damage to relatively stiff structures, common in urban areas. Spectra from selected accelerograms of near-source records are compared with the corresponding elastic spectra of the current Greek Seismic Code, (EAK 2000), the impulsive character of the Greek near-source records is ascertained and shortcomings of EAK 2000 to account for near-source effects are demonstrated. Based on records from seismic events in Greece and records from international earthquakes of small-to-moderate magnitude, the study demonstrates that there exists a near-source magnitude-distance region, where the velocity pulses have smaller amplitude and period in comparison with earthquakes of great magnitude. A simplified representation of three pulse types is, also, adopted for near-source events. It is found that the type-A pulse related to permanent displacement phenomena does not characterize Greek records. In addition a simple criterion is developed to identify the most appropriate simplified pulse type for near-source seismic events independently of magnitude.

Impulsive control of Lagrangian systems and locomotion in fluids

Aim of this paper is to provide a survey of the theory of impulsive control of Lagrangian systems. It is assumed here that an external controller can determine the evolution of the system by directly prescribing the values of some of the coordinates. We begin by motivating the theory with a couple of elementary examples. Then we discuss the analytical form taken by the equations of motion, and their impulsive character. The following sections review various results found in the literature concerning the continuity of the control-to-trajectory map, the existence of optimal controls, and the asymptotic controllability to a reference state. In the last section we indicate a further application of the theory, to the control of deformable bodies immersed in a fluid.

Second Fiddle: Or How To Tell a Blackbird from a Sausage (review)

Reviewed by: Second Fiddle: Or How To Tell a Blackbird from a Sausage Deborah Stevenson Parkinson, Siobhán Second Fiddle: Or How To Tell a Blackbird from a Sausage. Roaring Brook, 2007 [192p] ISBN 1-59643-122-9$16.95 Reviewed from galleys R Gr. 5-7 Mags first encounters Gillian in, of all places, the forest, where the latter goes to practice her violin. Twelve-year-old Mags, one of life's chargers-ahead, latches onto Gillian and soon discovers that the older girl is a truly gifted violinist, so gifted that she's been invited to audition for entry to a prestigious English music school. When Mags hears that there's an obstacle—Gillian's mother doesn't have tuition money—and that Gillian's divorced and seldom-in-contact father is Gillian's only hope for funding, she determines to track down Gillian's dad and extract the promise of financial support from him. Parkinson, author of the touching Something [End Page 434] Invisible (BCCB 5/06), shows her usual high style in Mags' narration; Mags is credible as a headstrong and impulsive character, and the correlation between her determination to find Gillian's father and the hole in her family left by her own father's death is wisely left largely implicit. The plot is, as a consequence, somewhat diffuse in its focus, and the narration tips into the arch at times (especially when Mags is explaining that she's also writing the chapters in Gillian's voice), but it's still a highly original story with a vividly drawn protagonist. Fans of lively family drama will appreciate Mags' energetic quest and her own unobtrusive steps toward maturation. Copyright © 2007 The Board of Trustees of the University of Illinois

Theoretical Predictions and Actual Hearing Threshold Levels in Workers Exposed to Ultrasonic Noise of Impulsive Character— A Pilot Study

Results of standard pure-tone audiom etry (PTA) were collected from 25 workers, mainly females, aged 23–58 years, exposed for 2–13 years to ultrasonic noise emitted by ultrasonic welders. Hearing tests were completed by evaluation of exposure to ultrasonic noise. The subjects’ actual audiometric hearing threshold levels (HTLs) were compared with theoretical predictions calculated according to ISO 1999:1990. In 60% of cases sound pressure levels in the 10–40 kHz 1/3-octave bands at workstands exceeded Polish exposure limits for ultrasonic noise. Our comparison of predicted and measured HTLs suggests that the ISO 1999:1990 method, intended for audible noise, might also make it possible to predict reliably permanent hearing loss (in the 2 000–6 000 Hz frequency range) after exposure to ultrasonic noise. No significant progress of hearing impairment (assessed using PTA) in the operators of ultrasonic welders was noted. Nevertheless, further studies on the hearing status of workers exposed to ultrasonic noise are needed.

Gender and Risk Factors for Suicide

It is unclear whether clinical and behavioral suicide risk factors, identified primarily among men, can be extended to women. We therefore explored sex differences in psychopathology and personality variants among suicide completers. Using the psychological autopsy method, we compared personality variants and the prevalence of psychopathology as a function of sex among 351 consecutive suicides in a large, urban community. Psychiatric diagnoses were obtained using the Structured Clinical Interview for DSM-IV-TR Axis I Disorders and the Structured Clinical Interview for DSM-IV Axis II Personality Disorders, and measures of impulsive aggression, temperament, and character were administered. Subsequently, we carried out secondary analyses between male and female suicides matched 2:1 for age, current depression, and number of lifetime depressive episodes. The study was conducted from late 2000 to 2005. Females were less likely to meet criteria for current and lifetime alcohol abuse, but those who did were less likely than males to have concurrent depression. On average, females were less impulsive, yet similar proportions of males and females were highly impulsive and impulsivity was associated with alcohol abuse irrespective of gender. Females were more likely to meet criteria for lifetime anxiety disorders; these were associated with nonviolent suicide methods, irrespective of gender. Despite a lower prevalence among females, high levels of impulsivity and alcohol abuse appear to be valid risk factors for both sexes. Researchers should focus on females for the identification of other suicide mediators.

Simulation of a binary mixture of adhesive fluids

Canonical Monte Carlo simulation is used to study the structure of a binary mixture of Baxter’s adhesive fluids. The simulation results are compared with the predictions resulting from the solution of the Percus–Yevick/Ornstein–Zernike equation. Two qualitatively different systems are considered, the one comprising adhesion among all possible species pairs and the other with attraction acting only between unlike particles. In the former case the correlation functions exhibit step discontinuities at the interparticle distances, which are the multiple of the molecular size of both species 1 and 2 as a consequence of the impulse character of 1–1, 2–2, and 1–2 adhesion. The latter system shows interesting shapes of correlation functions stemming from the interplay among the pure 1–1 and 2–2 repulsion, and 1–2 attractive interactions.

A case history of paroxysmal explosion at Stromboli: Timing and dynamics of the April 5, 2003 event

On April 5, 2003, Stromboli volcano (Italy) produced the most violent explosion of the past 50 years. The event was exceptionally well documented thanks to the presence on the island of several scientists and a large number of instruments deployed over the preceding months to monitor the effusive eruption that began in December 2002. Integration of visual documentation, deposit features and geophysical data allowed an accurate reconstruction of the explosive event and its dynamics. The eruption consisted of a 8-min long explosive event which evolved through four phases whose timing was precisely recorded by an infrared thermometer located about 450 m from the summit crater. Phases 2 and 3 lasted 39 and 42 s, respectively. Both had an impulsive character, were responsible for ejecting almost the entire mass of the pyroclastic products. Phases 1 and 4 represented, respectively, a short-lived precursory event and a waning tale. During Phase 2, meter-sized ballistic blocks were launched with velocities of 170 m/s to altitudes of up to 1400 m above the craters. These fell on the volcano flanks and on the village of Ginostra, about 2 km distant from the vent. A vertical jet rose above the craters which developed to feed a convective plume that reached a height of up to 4 km. The calculated mass of the Phase 2 fallout deposit and mass discharge rate were 1.1–1.4 × 10 8 kg and 2.8–3.6 × 10 6 kg/s, respectively. During Phase 3 a scoria flow deposit, with an estimated volume of 0.9–1.1 × 10 4 m 3, was erupted from the same vent that fed the ongoing sustained lava flow. The average mass discharge rate for this phase was 2.5–3.1 × 10 5 kg/s. Products emitted during Phases 2 and 3 consisted of lithic and fresh magmatic material in similar proportions. The juvenile fraction consisted of a deep-originated, almost aphyric, highly vesicular pumice mingled with a shallow-derived, crystal-rich, moderately vesicular scoria. Similarities with the eruption dynamics of other historical paroxysms at Stromboli makes the April 5, 2003 explosion representative of these highly energetic events that constitute the most hazardous volcanic phenomena at Stromboli volcano.

Investigation of the characteristics of dielectric barrier discharge in transition region

In the paper, we study the dielectric barrier discharge (DBD) occurring in a metal–insulator–gas–insulator–metal system. We encounter these kinds of discharges in ozonator-type reactors used in gas electrochemistry. The experiments are done in air medium when the gap width value is 580 µm and the pressure is in the interval of 1–100 mbar. The schematic diagram of the experimental mechanism and the drawing methods of the characteristics are given, and it is determined that the barrier discharge has an impulse character. Experimentally, we determine that the voltage–current (v–i) and voltage–charge (v–q) characteristics of the discharge are linear for the case of (pl) < (pl)cr and step shaped for the case of (pl) > (pl)cr, and these cases are explained theoretically. Furthermore, the determination method of the ratio of the fading voltage depending on the width of the steps of the experimental v–i characteristic to the inception voltage is given in this paper.

The Dynamic Programming Method in Impulsive Control Synthesis

The control synthesis problem is one of the central problems in modern control theory. Its solution can be obtained in various classes of feedback controls. For example, in classical control theory under a geometric constraint, the desired control ranges in the set of extreme points of the constraint, so that the synthesized system is described by differential equations with discontinuous right-hand side [1]. Sometimes, control synthesis can be described with the use of “switching surfaces” dividing the phase space into domains with continuous controls, while discontinuities (“switchings”) are allowed on these surfaces [2–4]. However, the solutions can have impulsive character in many applied problems, for example, in aerospace systems with instantaneous motion corrections, in systems with communication constrains, and in logical-dynamical systems. Such solutions require controls of generalized type, which consist of impulsive “delta functions” or their combinations with a bounded control. First program solutions in the impulsive control problem were obtained in [5]. It was shown in [6] that, in a linear impulsive problem, the number of jumps of an optimal control does not exceed the dimension of the phase space. Such problems were considered mainly from the viewpoint of program controls [4, 7, 8], while the construction of a well-formalized theory of impulsive control synthesis still remains an open problem. In the present paper, we show that dynamic programming methods can be applied to impulsive control problems in which solutions are sought in the form of synthesizing strategies. We consider linear systems, which permits one to combine the classical theory of distributions with the theory of generalized (viscosity) solutions [9–11] of the corresponding quasi-variational inequalities [12] of Hamilton–Jacobi–Bellman type. The suggested approach also permits one to study problems with higher-order derivatives of delta functions [13].

Quasiclassical dynamics simulation of the collision-induced dissociation of Cr(CO)6+ with Xe

Quasiclassical trajectory calculations are employed to investigate the dynamics of collision-induced dissociation (CID) of Cr(CO)6 + with Xe atoms at collision energies ranging from 1.3 to 5.0 eV. The trajectory simulations show that direct elimination of CO ligands, during the collision, becomes increasingly important as the collision energy increases. In a significant number of cases, this shattering mechanism is accompanied with a concomitant formation of a transient Xe-Cr(CO)x +(x<6) complex. The calculated results are in very good agreement with the experimental results presented previously [F. Muntean and P. B. Armentrout, J. Chem. Phys. 115, 1213 (2001)]. In particular, the computed cross sections and scattering maps for the product ions Cr(CO)x +(x=3-5) compare very favorably with the reported experimental data. However, in contrast with the conclusions of the previous study, the present calculations suggest that CID dynamics for this system exhibits a significant impulsive character rather than proceeding via a complex surviving more than a rotational period.

Creep–Slip Capture as a Possible Source of Squeal During Decelerated Sliding

Friction-induced vibration of a two-degree-of-freedom mass-damper-spring system interacting with a decelerating rigid strip is investigated. The friction law is approximated by an analytical function to facilitate the analyses and numerical integrations. It is shown that, after a quasi-harmonic transient period, accompanied by viscous energy dissipation, a short period of intensive ‘creep-slip’ vibration occurs, which generates a series of ‘micro-impacts’ on the strip. Because of the impulsive character of such kind of loading, its Fourier spectrum is rich and quite broadband. Using an averaging technique, the ‘normal form’ equations of motion show that the out-of-phase vibration mode absorbs more energy from the decelerating strip when its natural frequency satisfies certain resonance conditions. The study is then applied to an automotive disc brake model to gain useful insight into the generation of squeal. It is shown that the out-of-phase creep-slip vibration (in the longitudinal direction) of the brake pads generates an impulsive bending moment on the decelerating strip (disc rotor). This impulsive load may be considered as a possible source for brake squeal. The technique developed in this paper may be extended to other ‘squealing systems’ including models for geophysical faults (earthquakes).

MHD effects triggered by beams of fast particles in magnetic tubes and their possible relation to plasma heating and dynamics during solar flares

We study the magnetohydrodynamic response of a plasma in the low solar atmosphere to a changing current system of a flaring magnetictube, which contains a beam of fast non-thermal electrons. The local disturbances of a current system of a magnetic tube when the beam is injected into it are estimated using the classical idea of a return current. According to this idea, after injection of abeam, the total current density in a magnetic tube, which includes as well the current density of the beam jb, should not change compared to the current density in the tube before the injection. In order to keep constant the total current density j=j'+ jb, the current density of the magnetic tube j'in fact changes. This change is due to a return current jr.c.= –jb, which compensates the current density of the injected beam of fast electrons. At the same time, any changes of the current density in the magnetic tube change the Joule heating and disturb the thermodynamic equilibrium of the system. Changing of the plasma temperature destroys also the force balance and starts the process of complex dynamics of the whole plasma-magnetic structure. The impulsive character of a beam injection causes two stages in the dynamic behavior of the tube. During the first stage, characterized by the presence of a beam, the preliminary equilibrium state of a magnetic tube is disturbed and complex dynamics of the plasma start in the region of the beam propagation. During the second stage, when the injection of the beam is already over, the plasma and magnetic field continue to evolve from the disturbed state and gradually relax to an equilibrium state. Various types of magnetic tube response onto injection of a beam of energetic electrons are studied using the dynamic models of the magnetic tube (Khodachenko, 1996a; 1996b) built on the basis of known self-similar solutions of plasma MHD. The model results are applied to the interpretation of observed flaring and burst phenomena.

Annoyance of Low Frequency Noise (LFN) in the Laboratory Assessed by LFN-Sufferers and Non-Sufferers

In a series of listening tests, test subjects listened to eight different environmental low frequency noises to evaluate their loudness and annoyance. The noises were continuous noise with and without tones, intermittent noise, music, traffic noise and low frequency noises with an impulsive character. The noises were presented at LAeq levels of 20, 27.5 and 35 dB. The main group of test subjects (the reference group) comprised eighteen young persons with normal hearing. A special group of four subjects who had reported annoyance due to low frequency noise in their homes was also included. It was found that the special group generally assessed the annoyance of the noises much higher, especially the annoyance at night.

Comparison of Objective Methods for Assessment of Annoyance of Low Frequency Noise with the Results of a Laboratory Listening Test

Subjective assessments made by test persons were compared to results from a number of objective measurement and calculation methods for the assessment of low frequency noise. Eighteen young persons with normal hearing listened to eight environmental low frequency noises and evaluated the annoyance of the noises. The noises were stationary noise with and without tones, intermittent noise, music, traffic noise and impulsive low frequency noise. The noises were presented twice in a random order at LAeq levels of 20 dB, 27.5 dB and 35 dB. The assessment methods were those used in Sweden, Germany, The Netherlands, Poland and Denmark. It was found that the Danish assessment method gave the best relation to the subjective assessments made by the test persons. An important property of this method is that it includes a 5 dB penalty for noises having an impulsive character.

A Mathematical Representation of Near-Fault Ground Motions

A simple, yet effective, analytical model is proposed for the representation of near-field strong ground motions. The model adequately describes the impulsive character of near-fault ground motions both qualitatively and quantitatively. In addition, it can be used to analytically reproduce empirical observations that are based on available near-source records. The input parameters of the model have an unambiguous physical meaning. The proposed analytical model has been calibrated using a large number of actual near-field ground-motion records. It successfully simulates the entire set of available near-fault displacement, velocity, and (in many cases) acceleration time histories, as well as the corresponding deformation, velocity, and acceleration response spectra. Furthermore, a very simplified methodology for generating realistic synthetic ground motions that are adequate for engineering analysis and design is outlined and applied. Finally, it should be noted that the analytical model (along with the scaling laws of its parameters) proposed in the present work has the potential to facilitate the study of the elastic and inelastic response of conventional, nonconventional (e.g., base-isolated), and special structures (e.g., suspension bridges, fluid-storage tanks) subjected to near-source seismic excitations as a function of the model input parameters and thus, ultimately, as a function of earthquake size.

Grazing scattering of fast rare-gas atoms by adsorbed monolayers as a method of investigating gas–surface interaction with Ångström spatial resolution

A new method is proposed for studying the dynamics of interaction between superthermal (0.1–10 eV) gas particles and a solid surface with Ångström spatial resolution. The method is based on the use of grazing scattering of fast rare-gas atoms ( θ=1–5°, E 1=1–10 keV ) by monolayers of physically adsorbed particles. Due to the impulsive character of interaction and the translational symmetry of the physisorbed monolayer, one can introduce the concept of a pseudobeam of knocked-out atoms directed toward a certain point of the surface unit cell. An example of grazing scattering of fast Ar atoms by the ordered argon monolayer physisorbed on the Pt (1 1 1) surface is considered in detail. It is shown that the energy transfer to the platinum surface from the superthermal argon atoms to different points of surface can be measured in this case.

Complexity, magnetic field topology, criticality, and metastability in magnetotail dynamics

Recently, it has been shown that certain features of magnetotail dynamics in response to solar wind changes may resemble the behavior of a complex system near a dynamical critical state (Chang, Phys. Plasmas 6 (1999) 4137; Consolini and Chang, Space Sci. Rev. 95 (2001) 309), and of topological phase transitions (Chang, Phys. Scr. (2001), 80). Moreover, the impulsive part of the magnetotail response seems to be well described by cellular automata and other simulation models displaying criticality. Here, the relevance of the magnetic field topological disorder will be discussed in connection with observed complexity and near-criticality, showing how the impulsive character of the magnetotail response could be viewed as fluctuation-induced topological transitions among metastable configurations of magnetic field topology.