Rikesh Patel

Rikesh Patel
University of Nottingham | Notts · Department of Electrical and Electronic Engineering

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25
Publications
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396
Citations

Publications

Publications (25)
Article
Full-text available
Many engineering metals are polycrystalline, as such the elasticity, crystalline orientation and grain distribution are cardinal factors in determining the physical properties of the material. The grain distribution can be measured using a number of different techniques and the orientation by a subset of these (electron back scatter diffraction, sp...
Article
Spatially resolved acoustic spectroscopy (SRAS) is a laser ultrasound technique used to determine the crystallographic orientation (i.e., microstructure) of materials through the generation and measurement of surface acoustic wave velocity on a sample. Previous implementations have used a grating pattern imaged onto the surface to control the frequ...
Article
Full-text available
Detection of machining-induced white layers is currently a destructive inspection process with a form of cross-sectional microscopy required. This paper, therefore, reports on the development of a novel non-destructive inspection method for detecting white layers using grain size-sensitive and crystallographic texture-sensitive techniques. It is sh...
Article
Full-text available
Wire–arc additive manufacturing (WAAM) is an emergent method for the production and repair of high value components. Introduction of plastic strain by inter-pass rolling has been shown to produce grain refinement and improve mechanical properties, however suitable quality control techniques are required to demonstrate the refinement non-destructive...
Conference Paper
Full-text available
There is a clear industrial pull to fabricate high value components using premium high temperature aerospace materials by additive manufacturing. Inconveniently, the same material properties which allow them to perform well in service render them difficult to process via powder bed fusion. Current build systems are charac-terised by high defect rat...
Conference Paper
Full-text available
Spatially resolved acoustic spectroscopy (SRAS) is an acoustic microscopy technique that can image the microstructure and measure the crystallographic orientation of grains or crystals in the material. It works by measuring the velocity of surface acoustic waves (SAWs) via the acoustic spectrum. In the usual configuration, the SAWs are generated by...
Article
High-integrity engineering applications such as aerospace will not permit the incorporation of components containing any structural defects. The current generation of additive manufacturing (AM) platforms yield components with relatively high levels of defects. The in-line inspection of components built using AM can provide closed-loop feedback and...
Article
Full-text available
Additive manufacturing (AM) is a production technology where material is accumulated to create a structure, often through added shaped layers. The major advantage of additive manufacturing is in creating unique and complex parts for use in areas where conventional manufacturing reaches its limitations. However, the current class of AM systems produ...
Article
Full-text available
Orientation affects application-defining properties of crystalline materials. Hence, information in this regard is highly-prized. We show that electrochemical jet processing (EJP), when coupled with accurate metrological appraisal, can characterise crystallographic texture. Implementation of this technique allows localised dissolution to be anisotr...
Article
A major factor limiting the adoption of powder-bed-fusion additive manufacturing for production of parts is the control of build process defects and the effect these have upon the certification of parts for structural applications. In response to this, new methods for detecting defects and to monitor process performance are being developed. However...
Article
Full-text available
Developments in additive manufacturing technology are serving to expand the potential applications. Critical developments are required in the supporting areas of measurement and in process inspection to achieve this. CM247LC is a nickel superalloy that is of interest for use in aerospace and civil power plants. However, it is difficult to process v...
Article
Full-text available
Due to its economical production process polysilicon, or multicrystalline silicon, is widely used to produce solar cell wafers. However, the conversion efficiencies are often lower than equivalent monocrystalline or thin film cells, with the structure and orientation of the silicon grains strongly linked to the efficiency. We present a non-destruct...
Article
Full-text available
Recent years have heralded the introduction of metasurfaces that advantageously combine the vision of sub- wavelength wave manipulation, with the design, fabrication and size advantages associated with surface excitation. An important topic within metasurfaces is the tailored rainbow trapping and selective spatial frequency separation of electromag...
Article
Unlike more established subtractive or constant volume manufacturing technologies, additive manufacturing methods suffer from a lack of in-situ monitoring methodologies which can provide information relating to process performance and the formation of defects. In-process evaluation for additive manufacturing is becoming increasingly important in or...
Article
Full-text available
Additive manufacturing (AM) is a manufacturing technique that typically builds parts layer by layer, for example, in the case of selective laser melted (SLM) material by fusing layers of metal powder. This allows the construction of complex geometry parts, which, in some cases cannot be made by traditional manufacturing routes. Complex parts can be...
Article
A novel system has been developed that can capture the wide-field interference pattern generated by interfering two independent and incoherent laser sources. The interferograms are captured using a custom CMOS modulated light camera (MLC) which is capable of demodulating light in the megahertz region. Two stabilised HeNe lasers were constructed in...
Article
Interferometry is used in a wide variety of fields for the instrumentation and analysis of subjects and the environment. When light beams interfere, an interference fringe pattern is generated. Captured widefield interference patterns can be used to determine changes in the optical path length of interfering beams across a 2D area. Two interferomet...
Article
A novel ultrastable widefield interferometer is presented. This uses a modulated light camera (MLC) to capture and stabilise the interferogram in the widefield heterodyne interferometer. This system eliminates the contribution of piston phase to the interferogram without the need for common path optics and results in a highly stable widefield inter...
Article
In this paper a method of taking widefield heterodyne interferograms using a prototype modulated light camera is described. This custom CMOS modulated light camera (MLC) uses analogue quadrature demodulation at each pixel to output the phase and amplitude of the modulated light as DC voltages. The heterodyne interference fringe patterns are generat...
Conference Paper
A method of detecting optical heterodyne interferometry fringes using a custom CMOS modulated light camera array has been developed. Widefield phase images are generated using quadrature demodulation and are kept stable using a feedback system.

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