Initial Direction Of Motion Research Articles

Self-propelled object that generates a boundary with amphiphiles at an air/aqueous interface

A benzoic acid (BA) disk was investigated as a novel self-propelled object whose driving force was the difference in surface tension. 4-Stearoyl amidobenzoic acid (SABA) was synthesized as an amphiphile to control the nature of motion based on intermolecular interactions between BA and SABA. The BA disk exhibited characteristic motion depending on the surface density of the SABA on the aqueous phase, that is, reciprocating motion as a one-dimensional motion and restricted and unrestricted motion as a two-dimensional motion. The trajectory of the reciprocating motion was determined by the initial direction of motion, and the boundary between an aqueous surface and the BA-SABA condensed molecular layer was used as the field’s boundary. The presented results indicate that the characteristic nature of motion can be designed at the molecular level based on the intermolecular interactions between an energy-source molecule and an amphiphile.

Theoretical and Empirical Models High Energy Electrons and Positrons in Relativistic

In recent theoretical study electrons or a positron penetrate through a target oil it interacts mainly in two ways, viz, slowing down process and elastic scattering. These two process complete each other depending upon the electron a positron initial kinetic energy as well as atomic number of material. Thus it becomes very difficult to sketch the exact picture of preparation of these particles. A comparison of our evaluated cross- saction with the available expremental data and other theoretical finding shows a reasonable agreement over the studied energy range. When electron or a Positron enters the materials the cross section for slowing down be in the majority over that for the elastic scattering begins to gain magnitude with decreasing energy of electron and positrons.Thus more and more the partical beam suffers divergence from the line of incidence. As these particles penetrate further, their initial kinetic energy, the cross- section for elastic scattering becomes very large. At this stage of diffusion sets in. In this condition for average cosine of multi scattering angular distributions becomes equal to 1/e and electron/ positrons target their initial direction of motion.

Association Between Failures in Perceptual Updating and the Severity of Psychosis in Schizophrenia

Recent accounts suggest that delusions and hallucinations may result from alterations in how prior knowledge is integrated with new information, but experimental evidence supporting this idea has been complex and inconsistent. Evidence from a simpler perceptual task would make clear whether psychotic symptoms are associated with overreliance on prior information and impaired updating. To investigate whether individuals with schizophrenia or schizoaffective disorder (PSZ) and healthy control individuals (HCs) differ in the ability to update their beliefs based on evidence in a relatively simple perceptual paradigm. This case-control study included individuals who met DSM-IV criteria for PSZ and matched HC participants in 2 independent samples. The PSZ group was recruited from the Maryland Psychiatric Research Center, Yale University, and community clinics, and the HC group was recruited from the community. To test perceptual updating, a random dot kinematogram paradigm was implemented in which dots moving coherently in a single direction were mixed with randomly moving dots. On 50% of trials, the direction of coherent motion changed by 90° midway through the trial. Participants were asked to report the direction perceived at the end of the trial. The Peters Delusions Inventory and Brief Psychiatric Rating Scale (BPRS) were used to quantify the severity of positive symptoms. Data were collected from September 2018 to March 2020 and were analyzed from approximately March 2020 to March 2021. Critical measures included the proportion of responses centered around the initial direction vs the subsequent changed direction and the overall precision of motion perception and reaction times. A total of 48 participants were included in the PSZ group (31 [65%] male; mean [SD] age, 36.56 [9.76] years) and 36 in the HC group (22 [61%] male; mean [SD] age, 35.67 [10.74] years) in the original sample. An independent replication sample included 42 participants in the PSZ group (29 [69%] male; mean [SD] age, 33.98 [11.03] years) and 34 in the HC group (20 [59%] male; mean [SD] age, 34.29 [10.44] years). In line with previous research, patients with PSZ were less precise and had slower reaction times overall. The key finding was that patients with PSZ were significantly more likely (original sample: mean, 27.88 [95% CI, 24.19-31.57]; replication sample: mean, 26.70 [95% CI, 23.53-29.87]) than HC participants (original sample: mean, 18.86 [95% CI, 16.56-21.16]; replication sample: mean, 15.67 [95% CI, 12.61-18.73]) to report the initial motion direction rather than the final one. Moreover, the tendency to report the direction of initial motion correlated with the degree of conviction on the Peters Delusions Inventory (original sample: r = 0.32 [P = .05]; replication sample: r = 0.30 [P = .05]) and the Brief Psychiatric Rating Scale Reality Distortion score (original sample: r = 0.55 [P = .001]; replication sample: r = 0.35 [P = .03]) and severity of hallucinations (original sample: r = 0.39 [P = .02]; replication sample: r = 0.30 [P = .05]). The findings of this case-control study suggest that the severity of psychotic symptoms is associated with a tendency to overweight initial information over incoming sensory evidence. These results are consistent with predictive coding accounts of the origins of positive symptoms and suggest that deficits in very elementary perceptual updating may be a critical mechanism in psychosis.

Overweighting of Initial Motion Information Correlates With Severity of Positive Symptoms in Schizophrenia

Recent predictive coding accounts suggest that alterations in how prior knowledge and new sensory inputs are integrated in perception and inference may be implicated in the emergence of delusions and hallucinations. We tested this model by manipulating the precision of sequentially-presented visual motion information, hypothesizing that the severity of positive symptoms would correlate with a bias towards the direction of initial motion.

Asymmetry of Ceramic Destruction under a High-Velocity Impact

Destruction of ceramic barriers under an axisymmetric high-velocity impact has been studied experimentally. The results of the investigations testify to the existence of a significant influence of the structure of ceramic materials on the process of their destruction. The process becomes asymmetric, which can lead to rotation of the impactor with conservation of its initial direction of motion. There are still no models describing the asymmetric character of high-strength ceramic destruction. The probabilistic approach to describing strength characteristics of materials is a possible approach to creating such models.

Formation region effects in transition radiation, bremsstrahlung, and ionization loss of ultrarelativistic electrons

The processes of transition radiation and bremsstrahlung by an ultrarelativistic electron as well as the effect of transition radiation influence upon the electron ionization loss in thin layer of substance are theoretically investigated in the case when radiation formation region has macroscopically large size. Special attention is drawn to transition radiation (TR) generated during the traversal of thin metallic plate by the electron previously deflected from its initial direction of motion. In this case TR characteristics are calculated for realistic (circular) shape of the electron deflection trajectory. The difference of such characteristics under certain conditions from the ones obtained previously with the use of approximation of anglelike shape of the electron trajectory (instant deflection) is shown. The problem of measurement of bremsstrahlung characteristics in the prewave zone is investigated. The expressions defining the measured radiation distribution for arbitrary values of the size and the position of the detector used for radiation registration are derived. The problem of TR influence upon the electron ionization loss in thin plate and in a system of two plates is discussed. The proposal for experimental investigation of such effect is formulated.

Comparison of IMU Measurements of Curling Stone Dynamics with a Numerical Model

Despite almost a century of research, the question of what causes a curling stone to curl (move perpendicular to its initial direction of motion) has no complete answer. Many hypotheses have been formulated, but none has been able to account quantitatively for the full magnitude of the observed curl. The objective of this research was to equip a curling stone with an inertial measurement unit (IMU) and measure its motion, in order to verify a previously published, numerical model of curling stone dynamics. Low cost, small size, accuracy, ease of programming and operation, wireless data communication, and a data-sampling rate near 1kHz, were selection criteria and constraints for the instrument package. We used the MicroStrain 3DM-GX4-25 system. This is a MEMS-based IMU with a tri-axial gyroscope and a tri-axial linear accelerometer. It was mounted and interfaced with a Bluetooth transmitter, on a curling stone handle. The data were streamed to a host laptop and displayed graphically in real time. Post-processing of the data included filtering and time-integration in order to obtain linear and angular velocities, and displacements. We have compared our experimental results with trajectory data calculated using a previously published numerical model, based on a thermodynamic approach to ice friction. While the observed longitudinal and angular motions are captured reasonably well by the model (errors of about 5% or less), no curl is predicted by the model.

Achieving an Artistic Violin Vibrato Applications of Research to the Classroom

Vibrato is an essential musical element in string instrument playing that enhances and facilitates expressive performance. However, the acquisition of a beautiful vibrato remains one of the most difficult skills for a young string player to obtain and for instructors to teach. There are many reasons that vibrato is a difficult skill to master. The vibrato motion is complex and only can be executed if the fundamental instrument position and left-hand position are established. Aspects such as appropriate rate, width and purported pitch center are frequently debated (Fischbach, 1998; Gillespie, 1996) and disagreement precludes a universal method for teaching vibrato. In recent years, a team of researchers, including John Geringer, Michael Allen and myself, embarked on a systematic investigation that explored some of the central issues debated by string pedagogues. Through a series of investigations, we explored elements of string players’ vibrato, including pitch center, continuity, initial direction of motion, finger employed, positions/pitch register, dynamic level, instrument type and performers’ experience level. Although many questions remain, results from these studies provide interesting information to teachers that may be beneficial when describing and designing instruction relative to vibrato. In this article, I will review the research conducted during the last century relative to vibrato performance practice and provide some research-based applications for the studio and classroom.

Parallel code NSBC: Simulations of relativistic nuclei scattering by a bent crystal

The presented program was designed to simulate the passage of relativistic nuclei through a bent crystal. Namely, the input data is related to a nuclei beam. The nuclei move into the crystal under planar channeling and quasichanneling conditions. The program realizes the numerical algorithm to evaluate the trajectory of nucleus in the bent crystal. The program output is formed by the projectile motion data including the angular distribution of nuclei behind the crystal. The program could be useful to simulate the particle tracking at the accelerator facilities used the crystal collimation systems. The code has been written on C++ and designed for the multiprocessor systems (clusters). Program summaryProgram title: NSBC (Nuclei Scattering by Bent Crystal)Licensing provisions: Standard CPC license, http://cps.cs.qub.ac.uk/license/license.htmlProgramming language: C++ (g++, icc compilers)Computer: multiprocessor systems (clusters)Operating system: any OS based on LINUX; the program was tested under Novell SLES 10Has the code been vectorized or parallelized?: Yes. The code contains MPI directivesRAM: about 1 MB per processorNumber of processors: >1Supplementary material: the user manual readme.pdf, utility to generate the beam of particles Beam_Generator.exe, the pdf presentation that is commented in the Sample A.Classification: 7.10, 11.10External routines: MPI library for GNU C++, Intel C++ compilersRunning time:In general, the running time T depends on the number of both processors N and particles P hitting the crystal, as well as on the crystal thickness. It can be estimated by the ratio T[min]=3⋅10−5⋅αR[μrad]⋅P/(N−1) for the 2.66 GHz processors, where αR is the crystal bending angle. In our tests the simulations were performed for a few thousands of particles into the crystal up to several mm thickness. The number of the 2.66 GHz processors used counted up to 30. The running time of about 5 min was registered at above mentioned conditions.Nature of problem:Here we deal with planar channeling of fast particles in a bent crystal. The channeled projectile moves along bent planes being in such a way deflected at large angles from the initial direction of motion. This effect is recognized as accelerator techniques to shape the beam. Another attractive phenomenon is known as the volume reflection of quasichanneled projectiles. Volume reflected projectiles can also be deflected at essential angles. In general, channeled and reflected particles are deflected in opposite directions and the initial beam is split into two beams. Hence, there is the practical interest to model the beam tracking in a bent crystal, to obtain the characteristic angles of deflection, to estimate the number of particles, which can be effectively deflected at large angles.Solution method:Initially the beam of relativistic nuclei hitting the bent crystal is considered. The velocity of a particle is defined by two components. The component along the beam direction is relativistic, while the transverse component is nonrelativistic. The particle trajectory in a crystal is defined by the continuous potential of bent planes. Hence, to obtain the trajectory the classical equation of motion is solved numerically. The initial position of a nucleus in the channel is suggested to be random that can be obtained from the uniform distribution. To take into account the multiple scattering of projectiles on crystal both electrons and nuclei the corrections to the trajectory is introduced from time to time. Finally, at the projectile fly-out from the crystal one can obtain the transverse velocity as well as the deflection angle.Restrictions:As known the theory of the channeling effect implies the critical Lindhard angle θL. Channeling takes place when the angle θ0 between the bent planes and the velocity of a particle at the crystal entrance face undergoes the condition |θ0|<θL. The quasichanneling appears when |θ0| exceeds the value θL but remains close to this value. Thus, it is not recommended to input large values of the crystal orientation angle |θC| which defines the range of angles θ0 (see in Section 2). Nevertheless, in our simulations we found the program gives correct results in the broad range of crystal orientation angles, for example, −18θL≤θC≤4θL for 400 GeV protons. Characteristic values of critical angle θL are about 10 μrad for the energy of projectile about 100 GeV/uamu.

Synthesis of a stabilizing control for a wheeled robot following a curvilinear path

The synthesis control problem for the plane motion of a wheeled robot with constrained control resource is studied. The goal of the control is to bring the robot to an assigned curvilinear trajectory and to stabilize its motion along it. A new change of variable is suggested that reduces the problem of stabilizing robot's motion to that of stabilizing the zero solution in the form that admits feedback linearization. A control law stabilizing robot's motion along an arbitrary curvilinear target trajectory is synthesized. For a straight target path, the closed-loop system is shown to be asymptotically stable for any initial conditions except for the case where the initial direction of motion is perpendicular to the target path.

Stabilizing Control for a Wheeled Robot Following a Curvilinear Path

The problem of finding a stabilizing control for a wheeled robot with constrained control resource following a curvilinear path is studied. The goal of the control is to bring the robot to an assigned path and to stabilize its motion along it. A new change of variable is suggested that reduces the problem of stabilizing robot's motion to that of stabilizing the zero solution in the form that admits feedback linearization. A control law stabilizing robot's motion along an arbitrary feasible curvilinear target path is synthesized. The new control is shown to be more efficient than the well-known linearizing feedback obtained from the celebrated chained-form representation of the system equations. For a straight target path, the closed-loop system is shown to be asymptotically stable for any initial conditions except for the case where the initial direction of motion is perpendicular to the target path.

松代群発地震の初期発展過程

Matsushiro earthquake swarm is a most well known and well studied earthquake swarm in the history of seismology. From viewpoints of geophysics, geology and geochemistry, various observations, field surveys and analyses had been made to reveal characteristics of the swarm. On the basis of these studies, several models had been proposed to explain why and how the swarm originated and developed. However, majority of studies had focused on the activity around the climatic stage of the swarm in 1966 and so far, studies on the initial stage of the swarm in mid 1965 had remained few due to lack of sufficient observation data. The exact area where the swarm was born had not been known and the swarm was vaguely believed to originate from the area around Mt. Minakami in former Matsushiro town (now belongs to Nagano city). Considering that the manner of initial development of swarm activity represents an important characteristic of the swarm earthquake, we tried to get more clear view about initial stage of the swarm activity in this study. We re-investigated seismograms obtained by routine observation and studied seismograms of temporal stations for the first time which had not been processed yet. By scanning analogue seismograms, we made a complete data set of S-P times with high precision for each station. Although the data set of S-P times from two stations are not sufficient for conventional hypocenter location, we were able to narrow down a possible source area of the swarm activity under the reasonable assumptions. By considering direction of initial motion of P waves and assuming local velocity model of the upper crust in the region and plausible focal depth of 4.5km of the swarm earthquake, we found that the area of swarm in the very beginning in August, 1965 is located about 4km north-east of the Matsushiro earthquake fault (MEF) in former Wakaho town near its border with former Matsushiro town. Size of the initial swarm area was 3-4km in diameter. While swarm activity in the initial region was gradually decaying in September new swarm activity appeared separately from the initial swarm area around southern and south-west part of the MEF. Activity in the new swarm area had been increasing and it was developed to more intense swarm after October, 1965 when establishment of temporal seismic station network of the Earthquake Research Institute, University of Tokyo enabled detailed hypocenter location. The new swarm area coincides with the area where large amount of ground water moved upward and was released on the ground surface in the climatic stage of the swarm. It was well known that source area of the swarm was split and expanded toward north-east and south-west after March, 1967 in its climatic stage. Present study on the initial development of swarm area suggested that characteristics of the Matsushiro earthquake swarm such as splitting and expansion of its source area toward northeast and southwest were inherent in their early stage of the activity in August and September, 1965.

The Dynamics of Periodically Forced Prolate Spheroids in a Quiescent Newtonian Fluid with Weak Inertia

The effects of convective and unsteady inertia on the dynamics of periodically forced neutrally buoyant prolate spheroids in a quiescent Newtonian fluid medium, at low Reynolds numbers have been modeled. The resulting nonlinear equations have been solved using appropriate numerical methods. Several tests including a perturbation analysis are performed to validate results. A preferred direction, which is identified as the initial direction of motion, is observed that manifests itself in the properties of the solution. Results of the behavior of various parameters with respect to the Reynolds number, aspect ratio of the spheroid and the amplitude of the periodic force are presented. The results are technologically important as they may lead to insights in the development of active dampeners and smart fluids.

Solution of problems of oblique penetration of axisymmetric projectiles into soft soil based on local interaction models

A comparative analysis of the solutions of the three-dimensional problem of the oblique penetration of a rigid body into soft soil is carried out arsing interaction models based on one-dimensional solutions of the problem of the spherical cavity expansion. Both the well-known self-similar analytical solutions for an incompressible medium as well as the generalized solution for a compressible elastoplastic medium with separation of the shock wave which arises are considered. Use of the incompressible medium hypothesis, disregarding flow separation, in estimating the maximum values of the resistive forces leads to large errors. Taking account of compressibility enables the resistive forces to be refined appreciably and enables a satisfactory estimate of the deviation of the trajectories of bodies from the initial direction of motion to the obtained. In the proposed method of solving oblique penetration problems, a three-dimensional problem is reduced, on the basis of the plane sections hypothesis and disregarding peripheral mass and momentum flows, to the combined solution of a number of axisymmetric problems for each meridional section. It is shown that, with well-known local interaction models, this approach enables the reliability of the calculation of both the force and the kinematic characteristics of the penetration process to be increased considerably due to the fact that the dynamics of the free surface and cavitation effects of the covitating flow are taken into account.

Dynamics of monopolar vortices on a topographic beta-plane

The dynamics of a cyclonic monopolar vortex on a topographic beta-plane are studied experimentally and theoretically. Detailed measurements of the vortex structure are conducted using high-resolution quantitative velocity measurements. The initial velocity profiles were described in terms of a radius Rvm, maximum azimuthal velocity vθm, and a dimensionless parameter α which characterizes the steepness of the velocity profile. The initial direction of motion of the monopolar vortex is critically dependent on α and weakly dependent of the initial strength and size of the vortex: isolated vortices (α ∼ 3) move north, whereas non-isolated vortices characterized by α ∼ 1 move northwest. When the azimuthal velocity decays slowly with radial distance (α &lt; 1.4), Rossby wave generation dominates the vortex dynamics and the translational speed of the vortex correlates with the Rossby wave speed. When the azimuthal velocity decays rapidly with radial distance (α &gt; 1.4) the vortex is isolated and the translational speed is much slower than the Rossby wave speed. To interpret the effect of the vortex structure on the direction of motion, a mechanistic model is developed which includes the Rossby force and a lift force arising from circulation around the vortex, but does not include the effect of Rossby waves. The Rossby force results from the integrated effect of the Coriolis force on the vortex and drives the vortex north; the lift force is determined from the circulation around the vortex and drives the vortex west. Comparison with the experimental data reveals two regimes: α &lt; 1.4, where the vortex dynamics are dominated by Rossby waves whereas for α &gt; 1.4 Rossby waves are weak and favourable agreement is found with the mechanistic model.

Rapidly rotating sliding cylinders: Trajectories with large lateral displacements

We show that rapidly rotating cylinders sliding on smooth surfaces can exhibit novel trajectories. The lateral deflection can be as large as the net displacement in the initial direction of motion. With a large enough initial angular speed, the cylinder can trace out a spiral trajectory having a large number of loops. An exact analytical result for large lateral deflection is also derived. PACS No.: 4600

Electron acceleration in combined laser and uniform electric fields

An exact analytical solution for the equation of motion of a single relativistic electron, injected initially at some angle ξ to the propagation direction of a linearly polarized plane-wave laser field of arbitrary intensity and a uniform electric field oriented anti-parallel to the laser propagation direction, is developed. The solution is then used to investigate the issue of electron acceleration to high energies in the prescribed fields. It is found that, in principle, an electron may be accelerated from rest or motion to several hundred GeV, if the uniform electric field strength Es approaches a critical value Esc = (mc)/(2πNe), where m and e are the mass and charge of the electron, c is the speed of light in vacuum, N is the number of field cycles in the pulse and is the Doppler-shifted frequency of the laser field as seen by the electron upon initial injection. The radiation losses during acceleration are shown to be negligible and the spectrum of the radiation emitted along the initial direction of motion (parallel injection) of the electron is shown to consist mostly of the fundamental laser frequency.

Soliton scattering in the O(3) model on a torus

Using numerical simulations, the stability and scattering properties of the O(3) model on a two-dimensional torus are studied. Its solitons are found to be unstable but can be stabilized by the addition of a Skyrme-like term to the Lagrangian. Scattering at right angles with respect to the initial direction of motion is observed in all cases studied. The model has no solutions of degree one, so when a field configuration that resembles a soliton is considered, it shrinks to become infinitely thin. A comparison of these results with those of the model defined on the sphere is made.

Effect of temperature on the bulk atomic relocation in low-energy collision cascades in silicon: A molecular dynamics study

Abstract The production of damage in a Si lattice by internally starting 100 eV self-recoils has been studied using a MD simulation. Different initial lattice temperatures below the Debye temperature for Si have been considered. The number of stable atomic displacements and the amount of atomic mixing increase with the initial target temperature. The increase with temperature of atomic mixing is nonlinear -appreciable changes take place between 300 and 500 K, while the difference between the amount of mixing corresponding to 0 and 300 K is negligibly small. The size of the cascade zone in which stable atomic displacements occur doubles itself for temperature changes between 0 and 300 K, with a value for 500 K lying in between. This nonmonotonic variation with the initial target temperature of the size of the cascade zone may have its origin in the correlation between the initial direction of motion of the starting recoil and the directions of thermal velocities of the neighbouring atoms around this recoil.

Mechanisms underlying the generation of averaged modified trajectories

In this work we have studied what mechanisms might possibly underlie arm trajectory modification when reaching toward visual targets. The double-step target displacement paradigm was used with inter-stimulus intervals (ISIs) in the range of 10---300 ms. For short ISIs, a high percentage of the movements were found to be initially directed in between the first and second target locations (averaged trajectories). The initial direction of motion was found to depend on the target configuration, and on D: the time difference between the presentation of the second stimulus and movement onset. To account for the kinematic features of the averaged trajectories two modification schemes were compared: the superposition scheme and the abort-replan scheme. According to the superposition scheme, the modified trajectories result from the vectorial addition of two elemental motions: one for moving between the initial hand position and an intermediate location, and a second one for moving between that intermediate location and the final target. According to the abort-replan scheme, the initial plan for moving toward the intermediate location is aborted and smoothly replaced by a new plan for moving from the hand position at the time the trajectory is modified to the final target location. In both tested schemes we hypothesized that due to the quick displacement of the stimulus, the internally specified intermediate goal might be influenced by both stimuli and may be different from the location of the first stimulus. It was found that the statistically most successful model in accounting for the measured data is based on the superposition scheme. It is suggested that superposition of simple independent elemental motions might be a general principle for the generation of modified motions, which allows for efficient, parallel planning. For increasing values of D the inferred locations of the intermediate targets were found to gradually shift from the first toward the second target locations along a path that curved toward the initial hand position. These inferred locations show a strong resemblance to the intermediate locations of saccades generated in a similar double-step paradigm. These similarities in the specification of target locations used in the generation of eye and hand movements may serve to simplify visuomotor integration.