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11 – 20 of 217Shichao Jiang, Xinliang Lu, Hongliang Wang, Kai Song and Yuanyuan Jiang
Detection of hidden defects of aluminum alloy plate with damping coating is a challenging problem. At present, only a few non-destructive testing methods exist to address this…
Abstract
Purpose
Detection of hidden defects of aluminum alloy plate with damping coating is a challenging problem. At present, only a few non-destructive testing methods exist to address this engineering problem. Without the restriction of skin effect, remote field eddy current (RFEC) overcomes the interference caused by the damping coating. The RFEC, which has potential advantages for detecting the hidden defects of aluminum plate with damping coating, can penetrate the metal plate to detect buried depth defects. This study aims to test how thick the RFEC sensor can penetrate the metal plate to detect the buried defects.
Design/methodology/approach
The magnetic field distribution characteristics are analyzed, the magnetic field intensity distribution is calculated, and the structure and parameters of the coil, magnetic circuit and shielding damping are determined through the two- and three-dimensional finite element simulation methods. Optimal excitation frequency is obtained, and the distance between the excitation coil and detection coil is determined by analyzing the relationship between excitation frequency and remote field points.
Findings
Simulation and experimental results verify the feasibility of applying the RFEC detection technology in detecting the hidden defects of aluminum alloy plate with damping coating.
Originality/value
In this paper, the RFEC testing model of hidden defects in aluminum plate sample with damping coating is established by using the finite element method.
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Ali Hashemi, Hamed Taheri and Mohammad Dehghani
To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit…
Abstract
Purpose
To prevent the coil from burning or getting damaged, it is necessary to estimate the duration of its operation as long as its temperature does not exceed the permissible limit. This paper aims to investigate the effect of switching on the thermal behavior of impregnated and nonimpregnated windings. Also, the safe operating time for each winding is determined.
Design/methodology/approach
The power loss of the winding is expressed as a function of the winding specifications. Using homogenization techniques, the equivalent thermal properties for the homogenized winding are calculated and used in a proposed thermal equivalent circuit for winding modeling and analysis. The validity and accuracy of the proposed model are determined by comparing its analysis results and simulation and measurement results.
Findings
The results show that copper windings have better thermal behavior and lower temperature compared to aluminum windings. On the other hand, by impregnating or increasing the packing factor of the winding, the thermal behavior is improved. Also, by choosing the right duty cycle for the winding current source, it is possible to prevent the burning or damage of the winding and increase its lifespan. Comparing the measurement results with the analysis results shows that the proposed equivalent circuit has an error of less than 4% in the calculation of the winding center temperature.
Research limitations/implications
In this paper, the effect of temperature on the electrical resistance of the coil is ignored. Also, rectangular wires were not investigated. Research in these topics are considered as future work.
Originality/value
By calculating the thermal time constant of the winding, its safe operation time can be calculated so that its temperature does not exceed the tolerable value (150 °C). The proposed method analyzes both impregnated and nonimpregnated windings with various schemes. It investigates the effects of switching on their thermal behavior. Additionally, it determines the safe operating time for each type of winding.
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Martin Ihle, Steffen Ziesche, Paul Gierth, Andreas Tuor, Jonathan Tigelaar and Oliver Hirsch
The purpose of this paper is to analyze a presentation of eddy current sensing coils for the turbo charger speed measurement, which were manufactured with the low temperature…
Abstract
Purpose
The purpose of this paper is to analyze a presentation of eddy current sensing coils for the turbo charger speed measurement, which were manufactured with the low temperature co-fired ceramic (LTCC) technology. The goal is to be able to manufacture small robust coils with complex geometries and improved signal output.
Design/methodology/approach
A crucial element for its performance is the quality factor of the embedded coil. Thanks to the use of the developed LTCC manufacturing processes, the lateral wounding distance of the printed coils can be reduced to 30 µm, and simultaneously, the aspect ratio should be enlarged compared to standard LTCC technologies. By the use of a novel printed double-D coil design, the overall sensor characteristics will be improved.
Findings
The metallization thickness can be simultaneously enhanced that results in the internal resistance being reduced. Thus, the inductivity and the ohmic resistance achieve an obvious optimization that results in significant improvement of the quality factor of the novel coils when compared to standard technologies. Embedded micro coils have a sintered metallization aspect ratio of more than one and thus an optimal performance differing clearly from prior art. Their reliability was proven through temperature cycle tests of over more than 1,300 h.
Research limitations/implications
The developed LTCC coil technology will be introduced in the JAQUET sensor portfolio of TE Connectivity for the measurement of turbocharger speed on both passenger cars and trucks. The measurement and control of turbochargers speed enables the optimal regulation of airflow into the engine thereby improving the fuel economy and leading to a reduction of engine emissions.
Originality/value
This paper shows fabrication and performance of the original manufactured LTCC coil for turbocharger speed sensors and its optimized signal output by the novel design.
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Fayaz Kharadi, Karthikeyan A, Virendra Bhojwani, Prachi Dixit, Nand Jee Kanu and Nidhi Jain
The purpose of this study is to achieve lower and lower temperature as infrared sensors works faster and better used for space application. For getting good quality images from…
Abstract
Purpose
The purpose of this study is to achieve lower and lower temperature as infrared sensors works faster and better used for space application. For getting good quality images from space, the infrared sensors are need to keep in cryogenic temperature. Cooling to cryogenic temperatures is necessary for space-borne sensors used for space applications. Infrared sensors work faster or better at lower temperatures. It is the need for time to achieve lower and lower temperatures.
Design/methodology/approach
This study presents the investigation of the critical Stirling cryocooler parameters that influence the cold end temperature. In the paper, the design approach, the dimensions gained through thermal analysis, experimental procedure and testing results are discussed.
Findings
The effect of parameters such as multilayer insulation, helium gas charging pressure, compressor input voltage and cooling load was investigated. The performance of gold-plated and aluminized multilayer insulation is checked. The tests were done with multilayer insulation covering inside and outside the Perspex cover.
Practical implications
By using aluminized multilayer insulation inside and outside the Perspex cover, the improvement of 16 K in cool-down temperature was achieved. The cryocooler is charged with helium gas. The pressure varies between 14 and 18 bar. The optimum cooling is obtained for 17 bar gas pressure. The piston stroke increased as the compressor voltage increased, resulting in total helium gas compression. The optimum cool-down temperature was attained at 85 V.
Originality/value
The cryocooler is designed to achieve the cool-down temperature of 2 W cooling load at 100 K. The lowest cool-down temperature recorded was 105 K at a 2 W cooling load. Multilayer insulation is the major item that keeps the thermal radiation from the sun from reaching the copper tip.
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Roman E. Chumakov and Kandidat Nauk
Develops a neural network based system for optimum assembly speeds using thread‐forming fasteners.
Abstract
Purpose
Develops a neural network based system for optimum assembly speeds using thread‐forming fasteners.
Design/methodology/approach
Uses a three layer neural network to optimise thread forming speeds based on thread diameter and pitch and the total number of thread coils.
Findings
The method demonstrates savings in energy and reduction in torque values of 20‐30 per cent.
Research limitations/implications
Provides a method that works even when less experimental data are available.
Practical implications
The method should provide a higher quality and reliability and allow thread‐forming fasteners to be used in new application areas.
Originality/value
Provides an efficient and less labour intensive method for insertion speed optimisation.
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Wojciech Stęplewski, Andrzej Dziedzic, Adam Kłossowicz, Paweł Winiarski, Janusz Borecki, Grażyna Kozioł and Tomasz Serzysko
– This paper aims to report the investigations of capacitors and inductors embedded into printed circuit boards (PCBs) designed in various layouts.
Abstract
Purpose
This paper aims to report the investigations of capacitors and inductors embedded into printed circuit boards (PCBs) designed in various layouts.
Design/methodology/approach
The research were focused on the components embedded into four-layer PCBs with different structures of the inner layers. Three special capacitive laminates for manufacturing of thin-film embedded capacitors and several types of coils in the form of a spiral, meander and solenoid are described. In addition, a part of the spiral-type coils was formed with an aperture in the center in which the magnetic core, made of soft magnetic composites’ material was placed to increase the coil inductance.
Findings
Various constructions of embedded capacitors and coils were designed and manufactured. Capacitance and loss tangent of capacitors to determine the repeatability of the production process were determined. Capacitor’s long-term stability analysis was performed by exposing test samples to elevated temperatures (70, 100 or 130°C), realized with the aid of heating plate, for at least 160 h. The temperature characteristics for the capacitance and loss tangent from 15 to 100°C were determined. Also the induction of different designs and layouts coils was determined.
Originality/value
The wide parameters’ characterization of capacitors and coils embedded into PCBs allow the analysis of their properties with regard to their practical application. The promising results of the realized measurements show that the capacitors and induction coils with studied structures can be widely used in the construction of embedded circuits into PCBs (e.g. filters, radio frequency identification systems and generators).
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The magnetic field generated or disturbed by an object is often overlooked when we need to inspect or detect it. In this tutorial Steve Macintyre describes the fundamental design…
Abstract
The magnetic field generated or disturbed by an object is often overlooked when we need to inspect or detect it. In this tutorial Steve Macintyre describes the fundamental design principles of a range of magnetic field sensors.
J.Y. Park and M.G. Allen
In many systems which utilise magnetic components, e.g., miniaturised DC‐DC converters,PCMCIA cards, and modem stand‐off transformers, the magnetic device is the largest…
Abstract
In many systems which utilise magnetic components, e.g., miniaturised DC‐DC converters, PCMCIA cards, and modem stand‐off transformers, the magnetic device is the largest single component in the package. Surface‐mount magnetic devices may be unacceptably thick where low profiles are required. The authors's approach to this problem is to use micromachining techniques to realise inductors and transformers built into the multilayer structure of a multi‐chip package, allowing compact integration with chips, sensors and other components. Microinductors and micro‐transformers composed of thick cores and multiwinding conductors have high inductance, high saturation current, and low resistance compared with previous integrated inductors. The total size of the microinductive device is 4 mm ×4 mm× 0.145 mm, having 156 turns of multilevel electroplated copper coils (40 μm thick) and electroplated permalloy magnetic core (35 μm thick). These devices have inductances up to 1.5 μH and current‐carrying capability of up to 3A steady DC current, making them applicable to power converters. The processing steps chosen are all low‐temperature, which allow the use of low‐cost substrates such as MCM‐L compatible materials.
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Introduces papers from this area of expertise from the ISEF 1999 Proceedings. States the goal herein is one of identifying devices or systems able to provide prescribed…
Abstract
Introduces papers from this area of expertise from the ISEF 1999 Proceedings. States the goal herein is one of identifying devices or systems able to provide prescribed performance. Notes that 18 papers from the Symposium are grouped in the area of automated optimal design. Describes the main challenges that condition computational electromagnetism’s future development. Concludes by itemizing the range of applications from small activators to optimization of induction heating systems in this third chapter.
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Huachen Zhu, Zhenghong Qian, Jiaofeng Zhang, Yucheng Sun, Ru Bai and Jianguo Zhu
It has been noted that the spin-valve sensor exhibits lower sensitivity with higher temperature because of the variation of GMR ratio, which could lead to the measurement error in…
Abstract
Purpose
It has been noted that the spin-valve sensor exhibits lower sensitivity with higher temperature because of the variation of GMR ratio, which could lead to the measurement error in applications where working temperature changes largely over seasons or times. This paper aims to investigate and compensate the temperature effect of the spin-valve sensor.
Design/methodology/approach
A spin-valve sensor is fabricated based on microelectronic process, and its temperature relevant properties are investigated, in which the transfer curves are acquired within a temperature range of −50°C to 125°C with a Helmholtz coil and temperature chamber.
Findings
It is found that the sensitivity of spin-valve sensor decreases with temperature linearly, where the temperature coefficient is calculated at −0.25 %/°C. The relationship between sensitivity of spin-valve sensor and temperature is well-modeled.
Originality/value
The temperature drift model of the spin-valve sensor’s sensitivity is highly correlated with tested results, which could be used to compensate the temperature influence on the sensor output. A self-compensation sensor system is proposed and built based on the expression modeled for the temperature dependence of the sensor, which exhibits a great improvement on temperature stability.
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