scholarly journals On the revealing closed circulations on satellite maps of dynamic topography of the ocean surface

2019 ◽  
Vol 55 (5) ◽  
pp. 114-125
Author(s):  
R. Y. Tarakanov
Keyword(s):  
Numerical Solution ◽  
Closed Loop ◽  
Ocean Surface ◽  
Dynamic Topography ◽  
Exact Numerical Solution ◽  
Local Maxima ◽  
Digital Maps ◽  
The Core ◽  
Numerical Grid

An algorithm for revealing closed multi-core circulations on digital maps of dynamic topography (DT) is described. The algorithm consists in the expansion of eddies over the area from their cores (local maxima/minima of the DT) until the DT sills corresponding to these cores are reached, and is carried out in several iterations until the points belonging to the closed circulations are completely exhausted. The algorithm is an exact numerical solution of the problem of determining the value of the DT for a closed loop, the most distant from the core of circulation. The algorithm takes into account the problems of nesting into each other circulations of a different sign, the possible intersection with each other of the circulation of a different sign on the numerical grid, as well as the possible existence of islands or floating ice inside the circulations. A method is described for gluing smaller DT maps with the circulations revealed on them to larger maps.

Distinguishing Closed Circulations from the Satellite Maps of the Dynamic Topography

2021 ◽  
Author(s):  
Roman Tarakanov
Keyword(s):  
Numerical Solution ◽  
Closed Loop ◽  
Dynamic Topography ◽  
Exact Numerical Solution ◽  
Local Maxima ◽  
Digital Maps ◽  
The Core ◽  
Numerical Grid

<p>An algorithm for distinguishing closed multicore circulations from digital maps of dynamic topography (DT) is described. The algorithm is based on the expansion of circulations over the area from their cores (local maxima/minima of the DT) until the DT thresholds corresponding to these cores are reached. The algorithm is performed in several iterations until the points belonging to the closed circulations are completely exhausted. The algorithm is an exact numerical solution of the problem of determining the value of the DT for a closed loop, the most distant from the core of circulation. The algorithm takes into account the problems of nesting circulations of different signs into each other, the possible intersecting of circulations with different signs on the numerical grid, and the possible existence of islands or floating ice inside the circulations. A method is described for merging smaller DT maps to larger maps with the circulations distinguished from the smaller maps.</p>

scholarly journals Analytical and Experimental Analyses of Nonlinear Vibrations in a Rotary Inverted Pendulum

2021 ◽  
Author(s):  
Mohammadjavad Rahimi dolatabad ◽  
Abdolreza Pasharavesh ◽  
Amir Ali Akbar Khayyat
Keyword(s):  
Analytical Solution ◽  
Numerical Solution ◽  
Closed Loop ◽  
Inverted Pendulum ◽  
Multiple Scales ◽  
Nonlinear Oscillations ◽  
Wide Frequency Range ◽  
Perturbative Method ◽  
Full State Feedback ◽  
Rotary Inverted Pendulum

Abstract Gaining insight into possible vibratory responses of dynamical systems around their stable equilibria is an essential step, which must be taken before their design and application. The results of such a study can significantly help prevent instability in closed-loop stabilized systems through avoiding the excitation of the system in the neighborhood of its resonance. This paper investigates nonlinear oscillations of a Rotary Inverted Pendulum (RIP) with a full-state feedback controller. Lagrange’s equations are employed to derive an accurate 2-DoF mathematical model, whose parameter values are extracted by both the measurement and 3D modeling of the real system components. Although the governing equations of a 2-DoF nonlinear system are difficult to solve, performing an analytical solution is of great importance, mostly because, compared to the numerical solution, the analytical solution can function as an accurate pattern. Additionally, the analytical solution is generally more appealing to engineers because their computational costs are less than those of the numerical solution. In this study, the perturbative method of multiple scales is used to obtain an analytical solution to the coupled nonlinear motion equations of the closed-loop system. Moreover, the parameters of the controller are determined, using the results of this solution. The findings reveal the existence of hardening- and softening-type resonances at the first and second vibrational modes, respectively. This led to a wide frequency range with moderately large-amplitude vibrations, which must be avoided when adjusting a time-varying set-point for the system. The analytical results of the nonlinear vibration of the RIP are verified by experimental measurements, and a very good agreement is observed between the results of both approaches.

Exact numerical solution for asymmetric charge transfer

1964 ◽  
Vol 10 (3) ◽  
pp. 284-285
Author(s):  
R.A. Willet ◽  
S.G. Elkomoss
Keyword(s):  
Charge Transfer ◽  
Numerical Solution ◽  
Exact Numerical Solution

The error-based minimal control synthesis algorithm with integral action

2003 ◽  
Vol 217 (3) ◽  
pp. 187-201 ◽  
Author(s):  
D P Stoten ◽  
S A Neild
Keyword(s):  
Closed Loop ◽  
Control Synthesis ◽  
Closed Loop System ◽  
Synthesis Algorithm ◽  
The Core ◽  
Gain Term ◽  
Integral Action ◽  
Implementation Studies ◽  
Hyperstability Theory ◽  
Integral Gain

This paper presents a new form of the direct adaptive minimal control synthesis (MCS) algorithm. As its name suggests, the error-based minimal control synthesis with integral action (Er-MCSI) algorithm is solely driven by error signals that are generated within the closed-loop system, and contains an explicit integral gain term. The purpose of this new structure is, respectively, to remove the problem of variable adaptive effort with changes in the operating set point, and to remove gain ‘wind-up’ effects due to plant disturbances and signal offsets. The core of this paper contains a proof of stability for Er-MCSI, based on hyperstability theory, together with supporting simulation and implementation studies.

scholarly journals Mean Dynamic Topography of the Ocean Derived from Satellite and Drifting Buoy Data Using Three Different Techniques*

2009 ◽  
Vol 26 (9) ◽  
pp. 1910-1919 ◽  
Author(s):  
Nikolai Maximenko ◽  
Peter Niiler ◽  
Luca Centurioni ◽  
Marie-Helene Rio ◽  
Oleg Melnichenko ◽  
...  
Keyword(s):  
Ocean Surface ◽  
Horizontal Resolution ◽  
Global Ocean ◽  
Momentum Balance ◽  
Small Scale ◽  
Western Boundary ◽  
Dynamic Topography ◽  
Geoid Model ◽  
Near Surface ◽  
Mean Dynamic Topography

Abstract Presented here are three mean dynamic topography maps derived with different methodologies. The first method combines sea level observed by the high-accuracy satellite radar altimetry with the geoid model of the Gravity Recovery and Climate Experiment (GRACE), which has recently measured the earth’s gravity with unprecedented spatial resolution and accuracy. The second one synthesizes near-surface velocities from a network of ocean drifters, hydrographic profiles, and ocean winds sorted according to the horizontal scales. In the third method, these global datasets are used in the context of the ocean surface momentum balance. The second and third methods are used to improve accuracy of the dynamic topography on fine space scales poorly resolved in the first method. When they are used to compute a multiyear time-mean global ocean surface circulation on a 0.5° horizontal resolution, both contain very similar, new small-scale midocean current patterns. In particular, extensions of western boundary currents appear narrow and strong despite temporal variability and exhibit persistent meanders and multiple branching. Also, the locations of the velocity concentrations in the Antarctic Circumpolar Current become well defined. Ageostrophic velocities reveal convergent zones in each subtropical basin. These maps present a new context in which to view the continued ocean monitoring with in situ instruments and satellites.

scholarly journals Radiolysis Generates a Complex Organosynthetic Chemical Network

2019 ◽  
Author(s):  
Zachary Adam ◽  
Albert C. Fahrenbach ◽  
Sofia Marie Jacobson ◽  
Betul Kacar ◽  
Dmitry Yu. Zubarev
Keyword(s):  
Closed Loop ◽  
High Reactivity ◽  
Self Organization ◽  
Biological Organization ◽  
Radical Species ◽  
Organizational Attributes ◽  
The Core ◽  
Heavy Tailed Distributions ◽  
Precursor Synthesis ◽  
Heavy Tailed

<p><a></a><a>Origins of life chemistry has progressed from seeking out the production of specific molecules to seeking out conditions in which macromolecular precursors may interact with one another in ways that lead to biological organization. Reported precursor synthesis networks generally lack biological organizational attributes. </a>Radical species are highly reactive, but do their chemical reaction networks resemble living systems? Here we report the results of radiolysis reaction experiments that connect abundant geochemical reservoirs to the production of carboxylic acids, amino acids, and ribonucleotide precursors and study the topological properties of the resulting network. The network exhibits attributes associated with biological systems: it is hierarchically organized, there are families of closed loop cycles, and the species and cycle histograms exhibit heterogeneous (heavy-tailed) distributions. The core cycles of the network are made possible by the high reactivity of radical species such as H and OH. Radiolysis is implicated as a unique prerequisite for driving abiotic organosynthetic self-organization. </p>

Design of Control System of Brushless DC Motor Based on DSP

2014 ◽  
Vol 496-500 ◽  
pp. 1417-1421 ◽  
Author(s):  
Li Na Duan ◽  
Jin Zhao
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Brushless Dc Motor ◽  
Closed Loop Control ◽  
Signal System ◽  
Motor Speed ◽  
Loop Control ◽  
Brushless Dc ◽  
The Core ◽  
Control Segment

The System is at the core of TMS320F2812DSP from TI company to design the control system for BLDC motor, the control segment of it take advantage of the event manager EVA of the DSP to compare and produce six ways signal control.And utilize the capture module to acquire the state situation of the rotor-position sensor.Acording to the condition of hall sensor to control motor commutation.And solve the PWM signal system in the generation and motor speed feedback.It's easy to realize the motor closed-loop control, greatly simplify the system hardware design, improves the reliability of the system, reduces the volume of the system. Through the experiments,we gain the PWM waveform, and finally realize the purpose of reverse control .

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