Author
Rodney A. Badcock
Other affiliations: Brunel University London, University of Birmingham, Beijing Jiaotong University ...read more
Bio: Rodney A. Badcock is an academic researcher from Victoria University of Wellington. The author has contributed to research in topics: Electromagnetic coil & Magnet. The author has an hindex of 27, co-authored 138 publications receiving 2538 citations. Previous affiliations of Rodney A. Badcock include Brunel University London & University of Birmingham.
Papers published on a yearly basis
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Patent•
27 Sep 2002
TL;DR: In this article, the authors proposed a monitor for monitoring at least one optical signal parameter in an optical fiber having an access region of reduced cladding sufficient to allow access to the evanescent field.
Abstract: The invention relates to a monitor for monitoring at least one optical signal parameter in an opticl fibre having an access region of reduced cladding sufficient to allow access to the evanescent field. The monitor includes an optical element mountable adjacent to the access region of an optical fibre which optical element is capable of obtaining access to the evanescent field to enable use of the data therein to derive the at least one optical signal parameter.
161 citations
TL;DR: In this article, a mechanically rotating superconducting flux pump was used to excite an HTS double pancake coil at 77 K. This flux pump is found to possess an effective internal resistance, Reff, which varies linearly with frequency, and is two orders of magnitude larger than the measured series resistance of the soldered contacts within the circuit.
Abstract: Superconducting flux pumps enable large currents to be injected into a superconducting circuit, without the requirement for thermally conducting current leads which bridge between the cryogenic environment and room temperature. In this work, we have built and studied a mechanically rotating flux pump which employs a coated conductor high-Tc superconducting (HTS) stator. This flux pump has been used to excite an HTS double pancake coil at 77 K. Operation of the flux pump causes the current within the superconducting circuit to increase over time, before saturating at a limiting value. Interestingly, the superconducting flux pump is found to possess an effective internal resistance, Reff, which varies linearly with frequency, and is two orders of magnitude larger than the measured series resistance of the soldered contacts within the circuit. This internal resistance sets a limit for the maximum achievable output current from the flux pump, which is independent of the operating frequency. We attribute this ...
133 citations
TL;DR: In this article, a comparison of various transducer elements for Lamb wave detection is made and the use of embedded 0-3 piezocomposite elements demonstrated, and it has been shown that using the S0 Lamb mode may enable a quantitative estimate of the degree of damage to be obtained.
Abstract: The use of smart damage-detection systems may have considerable benefits for equipment operators. As sensing elements for a health-monitoring array, piezoelectric elements offer potential benefits. In particular, 0-3 piezocomposite elements have been identified as good candidates since they offer the potential for embedment within the advanced fibre composites. Ultrasonic Lamb waves have been shown to offer a technique for large-area damage detection for composites. It has been shown that the use of the S0 Lamb mode may enable a quantitative estimate of the degree of damage to be obtained. A comparison of various transducer elements for Lamb wave detection is made and the use of embedded 0-3 piezocomposite elements demonstrated.
109 citations
TL;DR: In this article, a brushless HTS-PM exciter is proposed to inject a superconducting DC current into the rotor coil circuit, which can significantly alter the thermal load upon the cryogenic system by removing the need for thermally inefficient normalconducting current leads.
Abstract: HTS synchronous generators, in which the rotor coils are wound from high-T c superconducting wire, are exciting attention due to their potential to deliver very high torque and power densities. However, injection of the large DC currents required by the HTS rotor coils presents a technical challenge. In this paper we discuss the development of a brushless HTS exciter which operates across the cryostat wall to inject a superconducting DC current into the rotor coil circuit. This approach fundamentally alters the thermal load upon the cryogenic system by removing the need for thermally inefficient normal-conducting current leads. We report results from an experimental laboratory device and show that it operates as a constant voltage source with an effective internal resistance. We then discuss the design of a prototype HTS-PM exciter based on our experimental device, and describe its integration with a demonstration HTS generator. This 200 RPM, 10 kW synchronous generator comprises eight double pancake HTS rotor coils which are operated at 30 K, and are energised to 1.5 T field through the injection of 85 A per pole. We show how this excitation can be achieved using an HTS-PM exciter consisting of 12 stator poles of 12 mm YBCO coated-conductor wire and an external permanent magnet rotor. We demonstrate that such an exciter can excite the rotor windings of this generator without forming a thermal-bridge across the cryostat wall. Finally, we provide estimates of the thermal load imposed by our prototype HTS-PM exciter on the rotor cryostat. We show that duty cycle operation of the device ensures that this heat load can be minimised, and that it is substantially lower than that of equivalently-rated conventional current leads.
98 citations
TL;DR: In this article, the effect of varying the size of the flux gap between the rotor magnets and coated conductor stator from 1 to 7.5 mm was investigated and it was shown that the performance of an experimental mechanically rotating HTS flux pump ceases to maintain a measurable output at flux gaps above 7.
Abstract: HTS flux pumps enable superconducting currents to be directly injected into a magnet coil without the requirement for thermally inefficient current leads. Here, we present results from an experimental mechanically rotating HTS flux pump employing a coated-conductor stator and operated at 77 K. We show the effect of varying the size of the flux gap between the rotor magnets and coated conductor stator from 1 to 7.5 mm. This leads to a corresponding change in the peak applied perpendicular magnetic field at the stator from approximately 350 to 50 mT. We observe that our experimental device ceases to maintain a measurable output at flux gaps above 7.5 mm, which we attribute to the presence of screening currents in the stator wire. We show that our mechanically rotating flux pump is well described by a simple circuit model which enables the output performance to be described using two simple parameters, the open-circuit voltage V oc and the internal resistance, R d. Both of these parameters are found to be directly proportional to magnet-crossing frequency and decrease with increasing flux gap. We show that the trend in R d can be understood by considering the dynamic resistance experienced at the stator due to the oscillating amplitude of the applied rotor field. We adopt a literature model for the dynamic resistance within our coated-conductor stator and show that this gives good agreement with the experimentally measured internal resistance of our flux pump.
89 citations
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01 Jan 2007
TL;DR: The Third edition of the Kirk-Othmer encyclopedia of chemical technology as mentioned in this paper was published in 1989, with the title "Kirk's Encyclopedia of Chemical Technology: Chemical Technology".
Abstract: 介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。
2,666 citations
TL;DR: Bergh and P.J.Dean as discussed by the authors proposed a light-emitting diode (LEDD) for light-aware Diodes, which was shown to have promising performance.
Abstract: Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.
1,560 citations
07 Apr 2002
TL;DR: An updated review covering the years 1996 2001 will summarize the outcome of an updated review of the structural health monitoring literature, finding that although there are many more SHM studies being reported, the investigators, in general, have not yet fully embraced the well-developed tools from statistical pattern recognition.
Abstract: Staff members at Los Alamos National Laboratory (LANL) produced a summary of the structural health monitoring literature in 1995. This presentation will summarize the outcome of an updated review covering the years 1996 2001. The updated review follows the LANL statistical pattern recognition paradigm for SHM, which addresses four topics: 1. Operational Evaluation; 2. Data Acquisition and Cleansing; 3. Feature Extraction; and 4. Statistical Modeling for Feature Discrimination. The literature has been reviewed based on how a particular study addresses these four topics. A significant observation from this review is that although there are many more SHM studies being reported, the investigators, in general, have not yet fully embraced the well-developed tools from statistical pattern recognition. As such, the discrimination procedures employed are often lacking the appropriate rigor necessary for this technology to evolve beyond demonstration problems carried out in laboratory setting.
1,467 citations
TL;DR: A comprehensive review on the state of the art of Lamb wave-based damage identification approaches for composite structures, addressing the advances and achievements in these techniques in the past decades, is provided in this paper.
1,350 citations
TL;DR: The recent research and development activities in structural health monitoring using FBG sensors have been critically reviewed, highlighting the areas where further work is needed.
Abstract: In-service structural health monitoring (SHM) of engineering structures has assumed a significant role in assessing their safety and integrity. Fibre Bragg grating (FBG) sensors have emerged as a reliable, in situ, non-destructive tool for monitoring, diagnostics and control in civil structures. The versatility of FBG sensors represents a key advantage over other technologies in the structural sensing field. In this article, the recent research and development activities in structural health monitoring using FBG sensors have been critically reviewed, highlighting the areas where further work is needed. A few packaging schemes for FBG strain sensors are also discussed. Finally a few limitations and market barriers associated with the use of these sensors have been addressed.
858 citations