scholarly journals The inverse problem of stabilization of a spherical pendulum in a given position under oblique vibration

2021 ◽  
Vol 8 (2) ◽  
pp. 255-269
Author(s):  
Аlexander G. Petrov ◽  
Keyword(s):  
Inverse Problem ◽  
High Frequency ◽  
Initial Conditions ◽  
Vibration Velocity ◽  
Spherical Pendulum ◽  
Acceleration Vector ◽  
Long Time ◽  
Minimum Amplitude ◽  
Vibration Parameters ◽  
Gravity Acceleration

The inverse problem is posed of stabilizing a spherical pendulum (a mass point at the end of a weightless solid rod of length l ) in a given position using high-frequency vibration of the suspension point. The position of the pendulum is determined by the angle between the pendulum rod and the gravity acceleration vector. For any given position of the pendulum, a series of oblique vibration parameters (amplitude of the vibration velocity and the angle between the vibration velocity vector and the vertical) were found that stabilize the pendulum in this position. From the obtained series of solutions, the parameters of optimal vibration (vibration with a minimum amplitude of velocity) are selected depending on the position of the pendulum. The region of initial conditions is studied, of which the optimal vibration leads the pendulum to a predetermined stable position after a sufficiently long time. This area, following N. F.Morozov et al., called the area of attraction.

scholarly journals Areas of attraction of the pendulum under the influence of oblique vibration of the suspension point

2021 ◽  
Vol 8 (3) ◽  
pp. 511-522
Author(s):  
Аlexander G. Petrov ◽  
Keyword(s):  
Inverse Problem ◽  
High Frequency ◽  
Velocity Vector ◽  
Vibration Characteristics ◽  
Vibration Velocity ◽  
Spherical Pendulum ◽  
Suspension Point ◽  
High Frequency Vibration ◽  
Stable Position ◽  
Regions Of Attraction

The inverse problem of stabilizing a spherical pendulum in a given position by means of high-frequency vibration of the suspension point is posed. The position of the pendulum is determined by the angle between the pendulum rod and the vertical. For any given position of the pendulum, a one-parameter series of oblique vibration characteristics (the amplitude of the vibration velocity and the angle between the vibration velocity vector and the vertical) is found to stabilize the pendulum in this position. For the obtained series, the regions of attraction are determined (the initial points from which a given stable position of the pendulum will be established under the influence of vibration).

scholarly journals Vibration parameters and indicators of a dynamic tillage tool

2021 ◽  
Vol 937 (3) ◽  
pp. 032048
Author(s):  
N Dzhabborov ◽  
A Dobrinov ◽  
A Sergeev
Keyword(s):  
Experimental Data ◽  
High Frequency ◽  
Soil Layer ◽  
Travel Speed ◽  
Vibration Velocity ◽  
Dynamic Impact ◽  
Energy Assessment ◽  
Oscillation Energy ◽  
Vibration Parameters ◽  
Elastic Elements

Abstract According to domestic and foreign research on the efficiency of active and passive vibrating tillage tools, the created vibration allows reducing the traction resistance of tillage implements compared to conventional tools, while improving the tillage quality. The study aimed to determine several vibration parameters and indicators of a dynamic tillage tool supplied with an energy storing and transmitting device: frequency and amplitude of oscillations, absolute velocity, vibration velocity, acceleration of vibration, a force of inertia, and oscillation energy. The study applied the energy assessment methods of tillage tools with the measuring and information system designed at IEEP – branch of FSAC VIM; analysis and generalisation of experimental data. Vibration variables were determined by the strain-gauge method. The study revealed a significant effect of oscillation frequency and amplitude of the tillage tool, depending on the machine travel speed and characteristics of elastic elements, on its vibration velocity and acceleration, the force of inertia and the energy of oscillations.The total increase in these forces owing to a high-frequency dynamic impact may affect the soil layer considerably as an additional loosening. The accumulated impact energy can provide a decrease in the traction resistance of the tillage tool.

Comparison of wavelet continuous transform and signal averaged ECG for high frequency content and late potential detection in healthy individuals

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
D Garcia Iglesias ◽  
J.M Rubin Lopez ◽  
D Perez Diez ◽  
C Moris De La Tassa ◽  
F.J De Cos Juez ◽  
...  
Keyword(s):  
High Frequency ◽  
Classical Method ◽  
Total Power ◽  
Frequency Content ◽  
Healthy Individuals ◽  
Time Frequency ◽  
Qt Intervals ◽  
Long Time ◽  
Power Content ◽  
High Frequency Content

Abstract Introduction The Signal Averaged ECG (SAECG) is a classical method forSudden Cardiac Death (SCD) risk assessment, by means of Late Potentials (LP) in the filtered QRS (fQRS)[1]. But it is highly dependent on noise and require long time records, which make it tedious to use. Wavelet Continuous Transform (WCT) meanwhile is easier to use, and may let us to measure the High Frequency Content (HFC) of the QRS and QT intervals, which also correlates with the risk of SCD [2,3]. Whether the HFC of the QRS and QT measured with the WCT is a possible subrogate of LP, has never been demonstrated. Objective To demonstrate if there is any relationship between the HFC measured with the WCT and the LP analyzed with the SAECG. Methods Data from 50 consecutive healthy individuals. The standard ECG was digitally collected for 3 consecutive minutes. For the WCT Analysis 8 consecutive QT complexes were used and for the SAECG Analysis all available QRS were used. The time-frequency data of each QT complex were collected using the WCT as previously described [3] and the Total, QRS and QT power were obtained from each patient. For the SAECG, bipolar X, Y and Z leads were used with a bidirectional filter at 40 to 250 Hz [1]. LP were defined as less than 0.05 z in the terminal part of the filtered QRS and the duration (SAECG LP duration) and root mean square (SAECG LP Content) of this LP were calculated. Pearson's test was used to correlate the Power content with WCT analysis and the LP in the SAECG. Results There is a strong correlation between Total Power and the SAECG LP content (r=0.621, p<0.001). Both ST Power (r=0.567, p<0.001) and QRS Power (r=0.404, p=0.004) are related with the SAECG LP content. No correlation were found between the Power content (Total, QRS or ST Power) and the SAECG LP duration. Also no correlation was found between de SAECG LP content and duration. Conclusions Total, QRS and ST Power measured with the WCT are good surrogates of SAECG LP content. No correlation were found between WCT analysis and the SAECG LP duration. Also no correlation was found between the SAECG LP content and duration. This can be of high interest, since WCT is an easier technique, not needing long recordings and being less affected by noise. Funding Acknowledgement Type of funding source: None

Evolution of solitary waves in a two-pycnocline system

2009 ◽  
Vol 642 ◽  
pp. 235-277 ◽  
Author(s):  
M. NITSCHE ◽  
P. D. WEIDMAN ◽  
R. GRIMSHAW ◽  
M. GHRIST ◽  
B. FORNBERG
Keyword(s):  
Solitary Waves ◽  
Initial Conditions ◽  
Oscillation Period ◽  
Resonance Phenomenon ◽  
Numerical Code ◽  
Asymptotic Model ◽  
Narrow Region ◽  
Near Resonance ◽  
Long Time ◽  
The Waves

Over two decades ago, some numerical studies and laboratory experiments identified the phenomenon of leapfrogging internal solitary waves located on separated pycnoclines. We revisit this problem to explore the behaviour of the near resonance phenomenon. We have developed a numerical code to follow the long-time inviscid evolution of isolated mode-two disturbances on two separated pycnoclines in a three-layer stratified fluid bounded by rigid horizontal top and bottom walls. We study the dependence of the solution on input system parameters, namely the three fluid densities and the two interface thicknesses, for fixed initial conditions describing isolated mode-two disturbances on each pycnocline. For most parameter values, the initial disturbances separate immediately and evolve into solitary waves, each with a distinct speed. However, in a narrow region of parameter space, the waves pair up and oscillate for some time in leapfrog fashion with a nearly equal average speed. The motion is only quasi-periodic, as each wave loses energy into its respective dispersive tail, which causes the spatial oscillation magnitude and period to increase until the waves eventually separate. We record the separation time, oscillation period and magnitude, and the final amplitudes and celerity of the separated waves as a function of the input parameters, and give evidence that no perfect periodic solutions occur. A simple asymptotic model is developed to aid in interpretation of the numerical results.

scholarly journals Internal volumetric heat generation and heat capacity prediction during a material electromagnetic treatment process using hybrid algorithms

2018 ◽  
Vol 38 (1) ◽  
pp. 74-82
Author(s):  
Edgar García-Morantes ◽  
Iván Amaya-Contreras ◽  
Rodrigo Correa-Cely
Keyword(s):  
Inverse Problem ◽  
Heat Capacity ◽  
Electromagnetic Field ◽  
Heat Generation ◽  
Initial Conditions ◽  
Limited Range ◽  
First Case ◽  
Realistic Situation ◽  
Wide Range ◽  
Volumetric Heat Generation

This work considers the estimation of internal volumetric heat generation, as well as the heat capacity of a solid spherical sample, heated by a homogeneous, time-varying electromagnetic field. To that end, the numerical strategy solves the corresponding inverse problem. Three functional forms (linear, sinusoidal, and exponential) for the electromagnetic field were considered. White Gaussian noise was incorporated into the theoretical temperature profile (i.e. the solution of the direct problem) to simulate a more realistic situation. Temperature was pretended to be read through four sensors. The inverse problem was solved through three different kinds of approach: using a traditional optimizer, using modern techniques, and using a mixture of both. In the first case, we used a traditional, deterministic Levenberg-Marquardt (LM) algorithm. In the second one, we considered three stochastic algorithms: Spiral Optimization Algorithm (SOA), Vortex Search (VS), and Weighted Attraction Method (WAM). In the final case, we proposed a hybrid between LM and the metaheuristics algorithms. Results show that LM converges to the expected solutions only if the initial conditions (IC) are within a limited range. Oppositely, metaheuristics converge in a wide range of IC but exhibit low accuracy. The hybrid approaches converge and improve the accuracy obtained with the metaheuristics. The difference between expected and obtained values, as well as the RMS errors, are reported and compared for all three methods.

scholarly journals Clinic Case of Rare Type VI Osteogenesis Imperfecta

2019 ◽  
Vol 16 (1) ◽  
pp. 30-35
Author(s):  
Olga N. Ignatovich ◽  
Leyla S. Namazova-Baranova ◽  
Tea V. Margieva ◽  
Natalia V. Zhurkova ◽  
Kirill V. Savostyanov ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
High Frequency ◽  
Heterogeneous Group ◽  
Osteogenesis Imperfecta Type ◽  
Post Translational Modification ◽  
Rare Type ◽  
Genes Encoding ◽  
Long Time ◽  
Collagen Genes

Osteogenesis imperfect is genetically heterogeneous group of diseases which are characterized by bone brittleness and fractures. It was thought for a long time that this is happening due to mutations in collagen genes. However, within past decade the understanding of osteogenesis imperfecta etiology has changed as a result of genetics development. The majority of all cases is related to mutations in collagen genes whereas rare mostly recessive forms are related to mutations in genes encoding collagen post-translational modification. Mutations in SERPINF1 gene were chosen as molecular cause of osteogenesis imperfecta type VI in 2011. Thus the new pathophysiology of this disease was revealed. Children with osteogenesis imperfecta type VI have high-frequency of fractures despite the management with bisphosphonates because mineralized bone osteoid is considerably reduced.

scholarly journals On the Sensitivity of the Simulated Diurnal Cycle of Precipitation to 3-Hourly Radiosonde Assimilation: A Case Study over the Western Maritime Continent

2021 ◽  
Vol 149 (10) ◽  
pp. 3449-3468
Author(s):  
Joshua Chun Kwang Lee ◽  
Anurag Dipankar ◽  
Xiang-Yu Huang
Keyword(s):  
Diurnal Cycle ◽  
High Frequency ◽  
Initial Conditions ◽  
Rainfall Variability ◽  
Weather Prediction ◽  
Radiosonde Data ◽  
Western Coast ◽  
Maritime Continent ◽  
Model Biases ◽  
Diurnal Cycle Of Precipitation

AbstractThe diurnal cycle is the most prominent mode of rainfall variability in the tropics, governed mainly by the strong solar heating and land–sea interactions that trigger convection. Over the western Maritime Continent, complex orographic and coastal effects can also play an important role. Weather and climate models often struggle to represent these physical processes, resulting in substantial model biases in simulations over the region. For numerical weather prediction, these biases manifest themselves in the initial conditions, leading to phase and amplitude errors in the diurnal cycle of precipitation. Using a tropical convective-scale data assimilation system, we assimilate 3-hourly radiosonde data from the pilot field campaign of the Years of Maritime Continent, in addition to existing available observations, to diagnose the model biases and assess the relative impacts of the additional wind, temperature, and moisture information on the simulated diurnal cycle of precipitation over the western coast of Sumatra. We show how assimilating such high-frequency in situ observations can improve the simulated diurnal cycle, verified against satellite-derived precipitation, radar-derived precipitation, and rain gauge data. The improvements are due to a better representation of the sea breeze and increased available moisture in the lowest 4 km prior to peak convection. Assimilating wind information alone was sufficient to improve the simulations. We also highlight how during the assimilation, certain multivariate background error constraints and moisture addition in an ad hoc manner can negatively impact the simulations. Other approaches should be explored to better exploit information from such high-frequency observations over this region.

THE INFLUENCES OF TEMPERATURE AND CHAIN–CHAIN INTERACTION ON FEATURES OF SOLITONS EXCITED IN α-HELIX PROTEIN MOLECULES WITH THREE CHANNELS

2009 ◽  
Vol 23 (10) ◽  
pp. 2303-2322 ◽  
Author(s):  
XIAO-FENG PANG ◽  
MEI-JIE LIU
Keyword(s):  
Energy Transport ◽  
Initial Conditions ◽  
Dynamic Features ◽  
New Model ◽  
Protein Molecules ◽  
Long Time ◽  
The Stability ◽  
Α Helix ◽  
Increasing Temperature ◽  
Chain Interaction

The dynamic features of soliton transporting the bio-energy in the α-helix protein molecules with three channels under influences of temperature of systems and chain–chain interaction among these channels have been numerically studied by using the dynamic equations in a new model and the fourth-order Runge–Kutta method. This result obtained shows that the chain–chain interaction depresses the stability of the soliton due to the dispersed effect, but the stability of the soliton in the case of simultaneous motivation of three channels by an initial conditions is better than that in another initial condition. We also find from this investigation that the new soliton can transport steadily over 1000 amino acid residues in the cases of motion of long time of 120 ps, and retain their shapes and energies to travel towards the protein molecules after mutual collision of the solitons at the biological temperatures of 300 K. Therefore the soliton is very robust against the thermal perturbation of the α-helix protein molecules at 300 K. From the investigation of changes of features of the soliton with increasing temperature, we find that the amplitudes and velocities of the solitons decrease with increasing temperature of proteins, but the soliton disperses in the cases of higher temperature of 325 K and larger structure disorders. Thus we find that the critical temperature of the soliton occurring in the α-helix protein molecules is about 320 K. Therefore we can conclude that the soliton in the new model can play an important role in the bio-energy transport in the α-helix protein molecules with three channels at biological temperature, and the new model is possibly a candidate for the mechanism of this transport.

Energy-Aware Chaotic Communication in Wireless Sensor Network

2013 ◽  
Vol 367 ◽  
pp. 536-540 ◽  
Author(s):  
Raju Dutta ◽  
Shishir Gupta ◽  
Mukul K. Das
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Initial Conditions ◽  
Wireless Sensor ◽  
Time Behavior ◽  
Nonlinear Mathematical Model ◽  
Energy Aware ◽  
Long Time ◽  
Small Change ◽  
Authentic Data

A challenging task in wireless sensor network (WSN) is to deliver authentic data between source nodes and sink nodes. The collision or dead lock occurs when two or more close nodes are attempted to send data at the same time to the others node. To avoid such dead lock situation in the network we propose a nonlinear mathematical model. The effect of nonlinearity often renders a periodic solution unstable for certain parametric choices even a very small change in initial conditions can lead to different result in chaotic systems which appears to exhibit chaos for a range of parametric values when long time behavior studied. The local stability conditions for the system have been discussed and analyzed. Numerically simulations have been carried out to study the complex behavior of the system for reasonable ranges of parameters in WSN.

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