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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"impedance method"”.
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The Determination of Periodic Pulsating Flow in Complex Piping Systems Bythe Impedance Method
Made available in DSpace on 2014-12-09T17:13:46Z (GMT). No. of bitstreams: 1 6901485.pdf: 3825252 bytes, checksum: 8a12f6b1345fcb7f513c3ce814c2e771 (MD5) Previous issue date: 1968
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Considerations of the Impedance Method, Wave Propagation, and Wireless Systems for Structural Health Monitoring
… presented in this thesis is all based on the impedance method for structural health monitoring. The impedance method is an electro-mechanical technique which utilizes a single piezoelectric transducer as both a sensor and actuator. Due to the high frequencies of excitation used for the method, …
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Impedance-Based Structural Health Monitoring to Detect Corrosion
… rates may be large, traditional inspections methods and "find it and fix it" maintenance approaches may lead to catastrophic mechanical failures. Therefore, precise structural health monitoring of pre-crack surface corrosion is paramount to understanding and predicting the effect corrosion …
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Impedance-Based Structural Health Monitoring of Wind Turbine Blades
… life and allow for less conservative designs. Impedance-based SHM is a method which has shown promise on a wide variety of structures. The technique utilizes small piezoceramic (PZT) patches attached to a structure as self-sensing actuators to both excite the structure with high-frequency …
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Advancing Autonomous Structural Health Monitoring
… All the research is based on developing the impedance method for monitoring structural health. The impedance technique utilizes piezoelectric patches to interrogate structures of interested with high frequency excitations. These patches are bonded directly to the structure, so information …
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Assessing Structural Integrity using Mechatronic Impedance Transducers with Applications in Extreme Environments
This research reviews and extends the impedance-based structural health monitoring technique in order to detect and identify structural damage on various complex structures. The basic principle behind this technique is to apply high frequency structural excitations (typically higher than 30 kHz) …
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Development of a Self-Sensing and Self-Healing Bolted Joint
… In order to detect looseness in a joint the impedance health monitoring method is used. A new method of making impedance measurements for health monitoring that greatly reduces the equipment cost and equipment size was developed. This facilitates implementation of the impedance technique in …
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Development of Structural Health Monitoring Systems Incorporating Acoustic Emission Detection for Spacecraft and Wind Turbine Blades
… power dissipation of SHM systems employing the impedance and the Lamb wave methods. An acoustic emission sensor of the proposed system continuously monitors acoustic events, while the SHM system is in sleep mode. The SHM system is evoked to perform the SHM operation only when there is an …
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An electrochemical study on the ionic conductivity of ceramic electrolyte La1-2SrxCo3-yMyO3-sigma oxide and its Pd/Ag compsites
… conductivity, which was obtained by applying AC impedance method. Among these factors, temperature has the most significant impact on the ionic conductivity, for instance La0.2Sr0.8CoO3-d (LSCO) exhibits O2- conductivity of 2.56 A' 10-3 S/cm at 900A?C but of only 1.23 A' 10-7S/cm at 400A?C. …
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Crack Detection in Aluminum Structures
… two approaches to SHM: vibration based and impedance based, and to associate these with the NDE method of stress intensity factors. By examining these methods the goal is to try and answer some of the important questions in SHM process. The first is to experimentally validate a crack model …
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Estimation of cardiovascular indices by analysis of the arterial blood pressure signal
… end systole identification algorithms, Parabolic Method, Modified Herd's Method, Kouchoukos Correction Method, and Corrected Impedance Method achieved low root normalized mean squared errors (RNMSEs). This thesis also introduces and validates a novel algorithm to reconstruct instantaneous ABF …
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Obesity and cardiovascular disease. Aspects of methods and susceptibility.
… fat percentage (BF%), measured by bioelectrical impedance method, was an independent risk factor for cardiovascular morbidity and mortality in men and women. BF% was a stronger CVD risk factor in women than in men. The raised CVD risk associated with high BF% was reduced by physical activity. …
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Improving fault location through interpole analysis of circuit breaker and automatic reclose scheme operation
… development and evaluation of novel single ended impedance based fault location methods, which are easy and economical to implement in practice. The conventional single ended impedance based fault location methods normally suffer from negative effects associated with variability and inaccuracies …
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Power System Frequency Control and Stability Analysis With Increasing Renewable Energy Penetration Level
… a deep insight into different inertial control methods while demonstrating the applicability of Virtual Synchronous Generator on wind power generation systems.</p> <p>The power system oscillation damping function initially provided by synchronous generators becomes unavailable with the …
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Structural Health Monitoring of Adhesively Bonded Joints With Piezoelectric Wafer Active Sensors
… detect damage that would escape some ultrasonic methods. The major focus of this research was directed towards the electromechanical impedance method for disbond detection. The electromechanical impedance (EMI) method was modeled extensively with analytical and finite element method; the …
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High Frequency Modeling and Experimental Analysis for Implementation of Impedance-based Structural Health Monitoring
A promising structural health monitoring (SHM) method for implementation on real world structures is impedance-based health monitoring. An in-service system is envisioned to include on board processing and perhaps wireless transfer of data. Ideally, a system could be produced as a slap-on or …
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REGENERATION OF ELECTROSPUN BIORESORBABLE VASCULAR GRAFTS: A PHENOMENON ASSOCIATED WITH VASCULAR GRAFT PROPERTIES AND MACROPHAGE PHENOTYPES (M1/M2)
… on the 60 mg/ml scaffold created by the air-flow impedance method compared to the 60 mg/ml scaffold created on the solid mandrel created by traditional electrospinning. The Arg1 expression was reduced on the compressed 140 mg/ml PDO scaffold compared to the normal 140 mg/ml scaffold. This result …
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ΜΕΛΕΤΗ ΟΡΘΟΓΩΝΙΚΩΝ ΚΑΙ ΤΡΙΓΩΝΙΚΩΝ ΜΙΚΡΟΤΑΙΝΙΑΚΩΝ ΚΕΡΑΙΩΝ
… OF THE OPTICAL RAYS (GEOMETRIC OPTICS THEORY) METHOD. CLOSED FORM EXPRESSIONS FOR THE TOTAL INTERNAL FIELD (UNDER THE PATCH) AND THE INPUT IMPEDANCE ARE GIVEN WITH THE AID OF AN ANGULARLY DEPENDED REFLECTION COEFFICIENT OFA TEM WAVE OBLIQUELLY INCIDEND OF THE EDGE OF THE PATCH. IN THESE …