Registration of confocal scanning laser microscopy and quantitative backscattered electron images for the temporospatial quantification of mineralization density in 18-month old thoroughbred racehorse articular calcified cartilage

Combined backscattered electron scanning electron microscopy (BSE SEM) and confocal scanning laser microscopy (CSLM) have been used to put tissue mineralization data into the context of soft tissue histology and fluorescent label information. Mineralization density (Dm) and linear accretion rate (LAR) are quantifiable parameters associated with mineralizing fronts within calcified tissues. Quantitative BSE (qBSE) may be used to determine Dm, while CSLM may be used to detect label fluorescence from which LAR is calculated. Eighteen-month old Thoroughbred horses received single calcein injections 19 and 8 days prior to euthanasia, labeling sites of active mineralization with fluorescent bands. Confocal scanning laser microscopy images of articular calcified cartilage (ACC) from distal third metacarpal condyles were registered to qBSE images of the same sites using an in-house program. ImageJ and Sync Windows enabled the simultaneous collection of LAR and Dm data. The repeatability of the registration and measurement protocols was determined. Dm profiles between calcein labels were explored for an association with time. Dm was 119.7 +/- 24.5 (mean +/- standard deviation) gray levels (where 0 = backscattering from monobrominated and 255 from monoiodinated dimethacrylate standards, respectively), while modal and maximum LAR were 0.45 and 3.45 microm/day, respectively. Coefficients of variation (CV) for Dm were 0.70 and 0.77% with and without repeat registration, respectively; CVs for LAR were 1.90 and 2.26% with and without repeat registration, respectively. No relationship was identified between Dm and time in the 11-day interlabel interval. Registration of CSLM to qBSE images is sufficiently repeatable for quantitative studies of equine ACC.     

Laser beam combiner for Thomson scattering core LIDAR

The light detection and ranging Thomson scattering (TS) diagnostic is advantageous since it only requires a single view port into the tokamak. This technique requires a short pulse laser at high energy, usually showing a limited repetition rate. Having multiple lasers will increase the repetition rate. This paper presents a scanning mirror as a laser beam combiner. Measurements of the position accuracy and jitter show that the pointing stability of the laser beam is within ±25?μrad for over tens of seconds. A control feedback loop is implemented to demonstrate the long term stability. Such a system could be applied for ITER and JET.     

Design and implementation of a full profile sub-cm ruby laser based Thomson scattering system for MAST

A major upgrade to the ruby Thomson scattering (TS) system has been designed and implemented on the Mega-ampere spherical tokamak (MAST). MAST is equipped with two TS systems, a Nd:YAG laser system and a ruby laser system. Apart from common collection optics each system provides independent measurements of the electron temperature and density profile. This paper focuses on the recent upgrades to the ruby TS system. The upgraded ruby TS system measures 512 points across the major radius of the MAST vessel. The ruby laser can deliver one 10 J 40 ns pulse at 1 Hz or two 5 J pulses separated by 100-800 μs. The Thomson scattered light is collected at F/15 over 1.4 m. This system can resolve small (7 mm) structures at 200 points in both the electron temperature and density channels at high optical contrast; ～50% modulated transfer function. The system is fully automated for each MAST discharge and requires little adjustment. The estimated measurement error for a 7 mm radial point is <4% of T(e) and <3% of n(e) in the range of 40 eV to 2 keV, for a density of n(e)=2×10(19) m(-3). The photon statistics at lower density can be increased by binning in the radial direction as desired. A new intensified CCD camera design allows the ruby TS system to take two snapshots separated with a minimum time of 230 μs. This is exploited to measure two density and temperature profiles or to measure the plasma background light.     

Innovative approach to investigating the microstructure of calcified tissues using specular reflectance Fourier transform-infrared microspectroscopy and discriminant analysis

Although bone fracture has become a serious global health issue, current clinical assessments of fracture risk based on bone mineral density are unable to accurately predict whether an individual is likely to suffer a fracture. There is increasing recognition that the chemical structure and composition, or microstructure, of mineralized tissues has an important role to play in determining the fracture resistance of bone. The objective of this preliminary study was to evaluate the use of specular reflectance Fourier transform infrared (SR FT-IR) microspectroscopy in conjunction with discriminant analysis as an innovative technique for providing future insights into the origins of orthopedic abnormalities. The impetus for this approach was that SR FT-IR microspectroscopy would offer several advantages over conventional transmission methods. Bone samples were obtained from young racehorses at known fracture predilection sites and spectra were successfully obtained from calcified cartilage and subchondral bone for the first time. By applying discriminant analysis to the spectral data set in biologically relevant regions, microstructural differences between groups of individuals were found to be related to features associated with both the mineral and organic components of the bone. The preliminary findings also suggest that differences in bone microstructure may exist between healthy individuals of the same age, raising important questions around the normal limits of individual variation and whether individuals may be predisposed to later fracture as a result of detrimental microstructural changes during early growth and development.     

Two-dimensional solitons in a Kerr cavity

Abstract

We study the existence and nature of soliton-like localized states in a passive cavity containing a Kerr medium driven by a plane-wave input field. As the background intensity is increased, these structures are always created in pairs, for topological reasons. The smaller ‘soliton’ is always unstable, while in two transverse dimensions the larger ‘soliton’ usually collapses to a singularity or decays.     

Lean,agile or leagile? Matching your supply chain to the marketplace

Many enterprises have pursued the lean thinking paradigm to improve the efficiency of their business processes. More recently, the agile manufacturing paradigm has been highlighted as an alternative to, and possibly an improvement on, leanness. In pursuing such arguments in isolation, the power of each paradigm may be lost, which is basically that agile manufacturing is adopted where demand is volatile, and lean manufacturing adopted where there is a stable demand. However, in some situations it is advisable to utilize a different paradigm on either side of the material flow de-coupling point to enable a total supply chain strategy. This approach we have termed the Leagile Paradigm. This paper therefore considers the effect of the marketplace environment on strategy selection to ensure optimal supply chain performance. Real-world case studies in the mechanical precision products, carpet making, and electronic products market sectors demonstrate the new approach to matching supply chain design to the actual needs of the marketplace.     

The use of optical reflected light and SEM imaging systems to provide quantitative coal characterisation

Emerging energy markets demand coal products with significantly different quality specifications to those used in coke making and conventional power generation. The suitability of different types of coal as particulate fuels requires a fully quantitative understanding of the nature and associations of both mineral and maceral constituents in individual coal particles. This characterisation defines not only the chemical attributes of coal assemblages, but also a predictive understanding of utilisation performance.Particle characterisation information is traditionally obtained using a combination of optical imaging methods for the organic constituents and SEM based determinations for detailed mineral information. New preparation methodologies have been developed to allow coal samples to be analysed much more effectively by both optical and SEM systems.Optical microscopy measurements of coal reflectance are traditionally carried out using an oil immersion lens. Recent tests show that measuring maceral reflectance in air can produce equivalent results to measurements made using an oil immersion lens. Thus a workflow is possible that makes for fast effective collection of data from both systems from the same surface. These developments are important precursors to fully integrating an optical imaging system with the latest SEM based developments on the FEG platform.     

Response of shielding structures to explosive loading

This paper presents the results of a numerical and experimental study of the behaviour of a brass hopper held in a supporting structure subjected to internal explosive loading. The structure is typical of those employed during the manufacture of explosive accessories. In such processes the hopper acts as a feed for the explosive while the encasing structure both supports the hopper and provides protection to the surroundings in the event of accidental initiation. The finite element model includes representations of the explosive, the brass hopper and the steel supporting structure. The boundaries between the components are treated as sliding and separable interfaces. Analysis is performed using the Oasys DYNA3D (version 5.1) finite element program. The numerical predictions for the deformations are compared with test results. The DYNA3D finite element code is shown to be an effective tool for the appriasal of this type of protective structure under explosive loading. Both the numerical and experimental studies point the way to improvements in the current design.