Resonance Tracking of Continua Using Self-Sensing Actuators

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Dominik Kern ◽  
Tobias Brack ◽  
Wolfgang Seemann
Keyword(s):  
Phase Difference ◽  
Power Transmission ◽  
Model Simplification ◽  
Practical Applications ◽  
Sensor Applications ◽  
Ultrasonic Motors ◽  
Harmonic Signals ◽  
Oscillation Modes ◽  
Linear Elements

This paper proposes and develops an innovative method to solve the resonance tracking problem for actuator and sensor applications to obtain maximum power transmission or signal selectivity using a modified phase-locked loop (PLL). The tracking of a higher eigenfrequency is very useful in some cases, but it is more challenging than the excitation of the only eigenfrequency of a 1-DoF system. The resonances are identified through employing their characteristic phase difference. The conventional PLL was modified to track a certain phase difference without deviation. The closed loop is a nonlinear control system due to the conversion between harmonic signals and phase signals. However, a model simplification to linear elements allows the goal oriented determination of the controller parameters. The advantages of self-sensing in combination with resonance tracking are attractive for practical applications such as ultrasonic motors and compact force sensors. The conducted experiments approved the effectiveness of the resonant excitation of higher oscillation modes of continua using self-sensing actuators.

scholarly journals Alcohol-based highly conductive polymer for conformal nanocoatings on hydrophobic surfaces toward a highly sensitive and stable pressure sensor

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Jung Joon Lee ◽  
Srinivas Gandla ◽  
Byeongjae Lim ◽  
Sunju Kang ◽  
Sunyoung Kim ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Mechanical Stability ◽  
Exchange Process ◽  
Conductive Polymer ◽  
High Sensitivity ◽  
Fast Response ◽  
Pdms Surface ◽  
Practical Applications ◽  
Sensor Applications ◽  
Water Based

Abstract Conformal and ultrathin coating of highly conductive PEDOT:PSS on hydrophobic uneven surfaces is essential for resistive-based pressure sensor applications. For this purpose, a water-based poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) solution was successfully exchanged to an organic solvent-based PEDOT:PSS solution without any aggregation or reduction in conductivity using the ultrafiltration method. Among various solvents, the ethanol (EtOH) solvent-exchanged PEDOT:PSS solution exhibited a contact angle of 34.67°, which is much lower than the value of 96.94° for the water-based PEDOT:PSS solution. The optimized EtOH-based PEDOT:PSS solution exhibited conformal and uniform coating, with ultrathin nanocoated films obtained on a hydrophobic pyramid polydimethylsiloxane (PDMS) surface. The fabricated pressure sensor showed high performances, such as high sensitivity (−21 kPa−1 in the low pressure regime up to 100 Pa), mechanical stability (over 10,000 cycles without any failure or cracks) and a fast response time (90 ms). Finally, the proposed pressure sensor was successfully demonstrated as a human blood pulse rate sensor and a spatial pressure sensor array for practical applications. The solvent exchange process using ultrafiltration for these applications can be utilized as a universal technique for improving the coating property (wettability) of conducting polymers as well as various other materials.

scholarly journals Calculations, norming and reducing of electrical energy losses in city electrical networks

2019 ◽  
Vol 21 (3) ◽  
pp. 46-54
Author(s):  
A. V. Lykin ◽  
E. A. Utkin
Keyword(s):  
High Voltage ◽  
Power Transmission ◽  
Low Voltage ◽  
Demand Curve ◽  
Electrical Energy ◽  
Electrical Network ◽  
Energy Losses ◽  
Capital Investments ◽  
Electrical Networks

The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.

scholarly journals 2D Propagation Simulation of Variation Parameters of U-shape Fiber Optic

2020 ◽  
Vol 10 (2) ◽  
pp. 153-158
Keyword(s):  
Fiber Optics ◽  
Power Flow ◽  
Fiber Optic ◽  
Power Transmission ◽  
Simulation Analysis ◽  
Reducing Power ◽  
High Sensitivity ◽  
Curvature Radius ◽  
Sensor Applications ◽  
Core Fiber

Fiber optic has extraordinary properties and is suitable in sensor applications due to its special potential. Currently, macro bending characteristics of newly developed hetero core fiber optic element are designed and evaluated. This paper presents the preliminary results obtained from the numerical simulation analysis of the bending sensitivity of U-shape fiber optics toward the 2D electromagnetic wave in terms of mesh, curvature radius, core fiber size, and turn number. Fiber optics with core sizes of 4, 9, 50, and 62.5 μm were designed. In addition, the combination of core diameters 50-4-50, 50-9-50, 62.5-4-62.5, and 62.5-9-62.5 μm is evaluated to compare the outcome of transmission power in terms of hetero core structure of fiber optic. Simulation is performed using COMSOL Multiphysics simulation tool. The developed U-shape fiber optic is designed to sense the distortion of reducing power transmission by comparing input and output power. Results show that the selected mesh depends on the size of geometry bending fiber optics, and fine and finer mesh is the best for U-shape fiber optic. Furthermore, the power flow on the fiber decreases with the decreasing curvature radius and increasing turn number. The fiber with a core size combination of 62.5–4–62.5 um has high sensitivity in terms of loss. The attained results possess higher potential in the field of sensor applications, such as displacement, strain, pressure, and monitoring respiration, on human body. This study serves as a basis for further investigation of nanomaterial coating on fiber optics, thereby enhancing its credibility for sensing.

Determination of a Suitable Moment for Formwork Removal from a Concrete Structure Using Rebound Hammer Test Methods

2021 ◽  
Vol 322 ◽  
pp. 23-27
Author(s):  
Petr Misák ◽  
Dalibor Kocáb ◽  
Petr Cikrle
Keyword(s):  
Compressive Strength ◽  
Characteristic Curve ◽  
Test Methods ◽  
Rebound Hammer ◽  
Practical Applications ◽  
Relevant Topic ◽  
Compressive Strength Of Concrete ◽  
The Moment ◽  
Non Destructive

Determining the compressive strength of concrete in the early stages of ageing has been an increasingly relevant topic in recent years, particularly with regard to the safe removal of formwork from a structure or its part. The compressive strength of concrete which designates safe removal of formwork without damaging the structure can be referred to as "stripping strength". It is undoubtedly beneficial to be able to determine the moment of safe formwork removal in a non-destructive manner, i.e. without compromising the structure. Modern rebound hammer test methods seem to be a suitable instrument with which it is possible to reduce the length of technological breaks associated with concrete ageing to a minimum, and consequently, reduce the total cost of the construction. However, the use of these methods presents a number of challenges. As many conducted experiments have shown, there is no single conversion relationship (regression model) between non-destructive rebound hammer test methods and compressive strength. It is therefore advisable to always create a unique conversion relationship for each individual concrete. In addition, it must be noted that conventional regression analysis methods operate with 50% reliability. In construction testing, however, the most common is the so-called characteristic value, which is defined as a 5% quantile. This value is therefore determined with 95% reliability. This paper describes the construction of a so-called "characteristic curve", which can be used to estimate the compressive strength of concrete in a structure using rebound hammer test methods with 95% reliability. Consequently, the values obtained from the characteristic curve can be easily used for practical applications.

Varieties of Human Serum Lipoprotein Pattern: Evaluation by Agarose Gel Electrophoresis

1971 ◽  
Vol 17 (5) ◽  
pp. 427-429 ◽  
Author(s):  
N M Papadopoulos ◽  
J A Kintzios
Keyword(s):  
Human Serum ◽  
Gel Electrophoresis ◽  
Clinical Laboratory ◽  
Serum Lipoprotein ◽  
Agarose Gel ◽  
Agarose Gel Electrophoresis ◽  
Practical Applications ◽  
Electrophoretic Technique ◽  
Lipoprotein Pattern

Abstract A previously reported agarose gel electrophoretic technique for the determination of serum lipoprotein patterns has been modified for analysis of a large number of samples for screening and epidemiological purposes. In addition, we demonstrate the varieties of lipoprotein patterns that can clearly be distinguished and visually evaluated for practical applications in the clinical laboratory.

scholarly journals Design and experimental analysis of dual-band polarization converting metasurface for microwave applications

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bilawal Khan ◽  
Babar Kamal ◽  
Sadiq Ullah ◽  
Imran Khan ◽  
Jawad Ali Shah ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Polarization State ◽  
Plane Waves ◽  
Microwave Frequency ◽  
Dual Band ◽  
Orthogonal Polarization ◽  
Frequency Bands ◽  
Practical Applications ◽  
Sensor Applications ◽  
Polarized Waves

Abstract The manipulation of polarization state of electromagnetic waves is of great importance in many practical applications. In this paper, the reflection characteristics of a thin and dual-band metasurface are examined in the microwave frequency regime. The metasurface consists of a 22 × 22 element array of periodic unit cells. The geometry of the unit cell consists of three layers, including a 45° inclined dipole shape metal patch on top, which is backed by a 1.6 mm thick FR-4 substrate in the middle, and a fully reflective metallic mirror at the bottom. The proposed surface is exposed to horizontally (x) or vertically (y) polarized plane waves and the co and cross polarization reflection coefficients of the reflected waves are investigated experimentally in the 6–26 GHz frequency range. The metasurface is designed to convert incident waves of known polarization state (horizontal or vertical) to orthogonal polarization state (vertical and horizontal) in two distinct frequency bands, i.e. 7.1–8 GHz and 13.3–25.8 GHz. In these two frequency bands the simulated and experimental results are in good agreement. The polarization conversion ratio (PCR) of the surface is greater than 95% in the targeted frequency bands. A detailed parametric analysis of the metasurface is also discussed in this work and it has been estimated that the surface has the additional ability to convert linearly polarized waves to circularly polarized waves at several distinct frequencies. The proposed metasurface can be utilized in sensor applications, stealth technology, electromagnetic measurements, and antennas design.

scholarly journals AOC-OPTICS: Automatic Online Classification for Condition Monitoring of Rolling Bearing

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 606
Author(s):  
Hassane Hotait ◽  
Xavier Chiementin ◽  
Lanto Rasolofondraibe
Keyword(s):  
Power Transmission ◽  
Rolling Bearing ◽  
Extraction Methods ◽  
Exponential Model ◽  
Essential Elements ◽  
Online Classification ◽  
Internal Parameters ◽  
Essential Components ◽  
Online Implementation

Bearings are essential components in rotating machines. They ensure the rotation and power transmission. So, these components are essential elements for industrial machines. Thus, real-time monitoring is required to detect a possible anomaly, diagnose the failure of rolling bearing and follow its evolution. This paper presents a methodology for automatic online implementation of fault diagnosis of rolling bearings, by AOC-OPTICS (automatic online classification monitoring based on ordering points to identify clustering structure, OPTICS). The algorithm consists of three phases namely: initialization, detection and follow-up. These phases use the combination of features extraction methods, smart ranking, features weighting and classification by the OPTICS method. Two methods have been integrated in the dimension reduction step to improve the efficiency of detection and the followed of the defect (relief method and t-distributed stochastic neighbor embedding method). Thus, the determination of the internal parameters of the OPTICS method is improved. A regression model and exponential model are used to track the fault. The analytical simulations discuss the influence of parameters automation. Experimental validation shows detection with 100% accuracy and regression models of monitoring reaching R 2 = 0.992 .

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