Optical measurement of shape and deformation fields on challenging surfaces

A multiple-sensor optical shape measurement system (SMS) based on the principle of white-light fringe projection has been developed and commercialised by Loughborough University and Phase Vision Ltd for over 10 years. The use of the temporal phase unwrapping technique allows precise and dense shape measurements of complex surfaces; and the photogrammetry-based calibration technique offers the ability to calibrate multiple sensors simultaneously in order to achieve 360° measurement coverage. Nevertheless, to enhance the applicability of the SMS in industrial environments, further developments are needed (i) to improve the calibration speed for quicker deployment, (ii) to broaden the application range from shape measurement to deformation field measurement, and (iii) to tackle practically-challenging surfaces of which specular components may disrupt the acquired data and result in spurious measurements. The calibration process typically requires manual positioning of an artefact (i.e., reference object) at many locations within the view of the sensors. This is not only timeconsuming but also complicated for an operator with average knowledge of metrology. This thesis introduces an automated artefact positioning system which enables automatic and optimised distribution of the artefacts, automatic prediction of their whereabouts to increase the artefact detection speed and robustness, and thereby greater overall calibration performance. This thesis also describes a novel technique that integrates the digital image correlation (DIC) technique into the present fringe projection SMS for the purpose of simultaneous shape and deformation field measurement. This combined technique offers three key advantages: (a) the ability to deal with geometrical discontinuities which are commonly present on mechanical surfaces and currently challenging to most deformation measurement methods, (b) the ability to measure 3D displacement fields with a basic single-camera single-projector SMS with no additional hardware components, and (c) the simple implementation on a multiple-sensor hardware platform to achieve complete coverage of large-scale and complex samples, with the resulting displacement fields automatically lying in a single global coordinate system. A displacement measurement iii accuracy of ≅1/12,000 of the measurement volume, which is comparable to that of an industry-standard DIC system, has been achieved. The applications of this novel technique to several structural tests of aircraft wing panels on-site at the research centre of Airbus UK in Filton are also presented. Mechanical components with shiny surface finish and complex geometry may introduce another challenge to present fringe projection techniques. In certain circumstances, multiple reflections of the projected fringes on an object surface may cause ambiguity in the phase estimation process and result in incorrect coordinate measurements. This thesis presents a new technique which adopts a Fourier domain ranging (FDR) method to correctly identifying multiple phase signals and enables unambiguous triangulation for a measured coordinate. Experiments of the new FDR technique on various types of surfaces have shown promising results as compared to the traditional phase unwrapping techniques

Developing Micro-Pipette Tips for Direct Writing Glutamate Biosensors in Neurological Applications

Glutamate excitotoxicity (GET) is a pathology in which excessive glutamate can cause neuronal damage and degeneration. It has also been linked to secondary injury mechanism, which further aggravates the damage in traumatic spinal cord injury (SCI). To date, there are various conventional bioanalytical techniques to characterize glutamate level in vivo, however, these techniques feature low spatiotemporal resolution, which has severely limited our understanding of this dynamic event. Currently, we are developing a microscale electrochemical glutamate biosensor using directional printing technique, that can be used to monitor the fluctuation of extracellular glutamate. Direct writing technique offers an alternative way to generate device patterns, in which architecture and composition can be controlled through computer-controlled translation stage. Functional materials can be deposited through a nozzle, therefore providing an ability to construct a 3-D structure with high aspect ratio and spanning features. Furthermore, nozzle size is directly correlated to the size of our printing biosensors. Thus, here we present our latest effort to create a custom made capillary micropipette, which will serve as a custom-made modality to print our biosensors with features as small as 30 µm.<br

Summary of population characteristics from domestic dogs sampled in a southwest United States and northern Mexico produce production region, November 3, 2010 through May 5, 2011 (N = 358).

a<p>Includes all dogs born in shelter, relinquished by owner, confiscated from owner, or dogs being kept for quarantine or treatment purposes.</p><p>Summary of population characteristics from domestic dogs sampled in a southwest United States and northern Mexico produce production region, November 3, 2010 through May 5, 2011 (N = 358).</p

Antimicrobial resistance patterns among 18 atypical enteropathogenic <i>Escherichia coli</i> (aEPEC) and 66 <i>Salmonella enterica</i> isolates from coyote and dog fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.

a<p>AMP, ampicillin; AUG2, amoxicillin/clavulanic acid; AXO, ceftriaxone; AZI, azithromycin; CHL, chloramphenicol; FIS, sulfisoxazole; FOX, cefoxitin; KAN, kanamycin; STR, streptomycin; SXT, trimethoprim/sulfamethoxazole; TET, tetracycline; XNL, ceftiofur.</p>b<p>O-, O antigen non-determinant.</p><p>Antimicrobial resistance patterns among 18 atypical enteropathogenic <i>Escherichia coli</i> (aEPEC) and 66 <i>Salmonella enterica</i> isolates from coyote and dog fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.</p

Subspecies and serovars of <i>Salmonella</i> isolated from dog and coyote fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.

<p>Subspecies and serovars of <i>Salmonella</i> isolated from dog and coyote fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.</p

Comparison of results from Shiga toxin-producing <i>E. coli</i> (STEC) O-group-specific (O103, O145, O157, O26) commercial latex agglutination screening tests and a multiplex PCR confirmatory test to detect 8 major STEC O-groups (O103, O111, O113, O121, O145, O157, O26, O45) used to serotype isolates cultured from fecal samples by selective enrichment and serogroup-specific (O103, O145, O157, O26) immunomagnetic separation (IMS).

a<p>All isolates were <i>stx</i>1 and <i>stx</i>2 negative.</p>b<p>Ten <i>eae</i>+ isolates classified as O103 by latex agglutination screening and negative by multiplex STEC PCR belonged to serotypes O114 (n = 1), O123 (n = 2), O126 (n = 1), O128 (n = 1), O167 (n = 1), O64 (n = 1) and O- (n = 3) using O-antisera.</p>c<p>Two <i>eae</i>+ isolates classified as O145 by latex agglutination screening and negative by multiplex STEC PCR belonged to serotypes O153 (n = 1) and O- (n = 1) using O-antisera.</p>d<p>Serotyping using O-antisera was not performed on isolates (n = 187) negative for virulence factors and not belonging to STEC O-groups identified by multiplex PCR.</p><p>Comparison of results from Shiga toxin-producing <i>E. coli</i> (STEC) O-group-specific (O103, O145, O157, O26) commercial latex agglutination screening tests and a multiplex PCR confirmatory test to detect 8 major STEC O-groups (O103, O111, O113, O121, O145, O157, O26, O45) used to serotype isolates cultured from fecal samples by selective enrichment and serogroup-specific (O103, O145, O157, O26) immunomagnetic separation (IMS).</p

Serotypes and virulence factors of <i>Escherichia coli</i> strains isolated from dog and coyote fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.

a<p>O-, O antigen non-determinant.</p>b<p>Twelve dog fecal samples contained two different serotypes including O103:H16/O113:H4 (n = 6); O26:H32/O103:H49 (n = 5); and O114:H8/O145:H11 (n = 1).</p><p>Serotypes and virulence factors of <i>Escherichia coli</i> strains isolated from dog and coyote fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.</p

Examples of animal intrusions into produce production areas of the desert southwest: a stray dog traveling next to an irrigation canal in northern Mexico (A); coyote feces adjacent to a lettuce field in southern California (B); dog feces on a lettuce plant in southern Arizona (C); areas of intentionally destroyed lettuce crop (arrow) following evidence of animal intrusion.

<p>Examples of animal intrusions into produce production areas of the desert southwest: a stray dog traveling next to an irrigation canal in northern Mexico (A); coyote feces adjacent to a lettuce field in southern California (B); dog feces on a lettuce plant in southern Arizona (C); areas of intentionally destroyed lettuce crop (arrow) following evidence of animal intrusion.</p

Monthly prevalence of atypical enteropathogenic <i>Escherichia coli</i> (aEPEC) and <i>Salmonella enterica</i> isolated from coyote and dog fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.

a<p>The Arizona shelter was sampled twice in March and in May. The California shelter was sampled twice in November. The shelter in Mexico was sampled twice in December and twice in February.</p><p>Monthly prevalence of atypical enteropathogenic <i>Escherichia coli</i> (aEPEC) and <i>Salmonella enterica</i> isolated from coyote and dog fecal samples, southwestern desert, November 3, 2010 through May 5, 2011.</p

<i>Escherichia coli</i> (<i>XbaI</i> restriction) pulsotypes of 18 aEPEC isolates and 2 non-pathogenicirulent <i>E. coli</i> O145:H11 isolates from dog and coyote fecal samples in the southwest desert produce growing areas of Arizona, California, and northern Mexico, November 3, 2010 through May 5, 2011.

<p>A human clinical <i>E. coli</i> O145:H28 outbreak strain associated with a Romaine lettuce-related outbreak traced to Arizona in May 2010 is also shown.</p