Crack problems in plane and antiplane elasticity using a singular integral equation

A numerical integration formula for the investigation of the singular integral of loakimidis for classical crack problems in plane and antiplane elasticity is developed. The method is based on a modification of the Gauss-Chebyshev quadrature and the definition of finite part integral having an algebraic sigularity of (−3/2) at the limits of integration. Once developed the procedure is applied to the determination of finite part integrals which have analytical solutions and the results are compared. Finally the integration for mula is applied to an actual crack problem and the stress intonsity factors are computed and presented.     

Microfiltration isolation of human urinary exosomes for characterization by MS

Purpose: The purpose of this study was to address the hypothesis that small vesicular urinary particles known as exosomes could be selectively microfiltered using low protein‐binding size exclusion filters, thereby simplifying their use in clinical biomarker discovery studies. Experimental design: We characterized a microfiltration approach using a low protein binding, hydrophilized polyvinylidene difluoride membrane to easily and efficiently isolate urinary exosomes from fresh, room temperature or 4°C urine, with a simultaneous depletion of abundant urinary proteins. Using LC‐MS, immunoblot analysis, and electron microscopy methods, we demonstrate this method to isolate intact exosomes and thereby enrich for a low abundant urinary proteome. Results: In comparison to other standard methods of exosome isolation including ultracentrifugation and nanofiltration, we demonstrate equivalent enrichment of the exosome proteome with reduced co‐purification of abundant urinary proteins. Conclusion and clinical relevance: In conclusion, we demonstrate a microfiltration isolation method that preserves the exosome structure, reduces contamination from higher abundant urinary proteins, and can be easily implemented into mass spectrometry analysis for biomarker discovery efforts or incorporation into routine clinical laboratory applications to yield higher sample throughput.     

A generative framework for fast urban labeling using spatial and temporal context

This paper introduces a multi-level classification framework for the semantic annotation of urban maps as provided by a mobile robot. Environmental cues are considered for classification at different scales. The first stage considers local scene properties using a probabilistic bag-of-words classifier. The second stage incorporates contextual information across a given scene (spatial context) and across several consecutive scenes (temporal context) via a Markov Random Field (MRF). Our approach is driven by data from an onboard camera and 3D laser scanner and uses a combination of visual and geometric features. By framing the classification exercise probabilistically we take advantage of an information-theoretic bail-out policy when evaluating class-conditional likelihoods. This efficiency, combined with low order MRFs resulting from our two-stage approach, allows us to generate scene labels at speeds suitable for online deployment. We demonstrate the virtue of considering such spatial and temporal context during the classification task and analyze the performance of our technique on data gathered over almost 17 km of track through a city.     

Evaluation and critique of Healthcare Failure Mode and Effect Analysis applied in a radiotherapy case study

Healthcare Failure Mode and Effect Analysis (HFMEA®) has been developed to support the proactive analysis of health care treatment processes. Its use has been reported in several studies with both positive and negative comments regarding the quality of the results and the efficacy of the method. This paper examines the HFMEA® methodology and discusses the challenges that were encountered during its application to a proactive analysis of radiotherapy patient record systems in a large public hospital. Several weaknesses in the HFMEA® method and particularly in the HFMEA Decision Tree^TM are also discussed. Recommendations to support future HFMEA® studies and also for the re‐design of the HFMEA Decision Tree^TM to overcome the identified weaknesses are included. Based on these recommendations, a new decision tree is presented to guide future analyses. © 2012 Wiley Periodicals, Inc.     

A photolithographic technique for reproducing submillimetre antennas

A method for producing submillimetre antennas and antenna arrays on quartz and Mylar substrates is described. A photolithographic technique has been employed to reproduce the arrays on Mylar substrates vacuum coated with silver. After depositing a thin layer of positive photoresist onto the silver, it is contacted with the mask and then irradiated with a uv lamp. The resist is developed and then the exposed metallisation is wet etched. The resulting antenna arrays have been found to exhibit electrical properties that are predictable from established theory     

CO2 laser pulse shortening by laser ablation of a metal target

A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO(2) laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to ~2 ns and to remove the low power, long duration tails that are present in TEA CO(2) pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is ~10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.     

Multichannel neutral-particle analyzer system

A multichannel neutral-analyzer system developed for the analysis of charge-exchange flux from magnetically confined plasma is described. The system uses tandem magnetic-electrostatic deflection of ions produced from neutrals stripped in a gas cell to obtain the energy spectra of specific charge-to-mass-ratio species. The analyzer is collimated with a spatial resolution of 2 cm FWHM at the plasma and is movable so that radial scans of charge-exchange flux can be made. Data are recorded digitally, allowing frequency response of fluctuations in charge-exchange flux up to 50 kHz. The calibration procedure employs an auxiliary single-channel analyzer calibrated over the full energy range of the multichannel instrument with an atomic-beam setup. Typical data obtained from the 2XIIB neutral-beam-injected mirror machine are briefly presented.     

Limits to tidal current power

Estimating the extractable power of tidal currents in channels is a practical question that has received attention recently. Analysis has clearly shown that the power potential is not given by the flux of kinetic energy, as has been commonly assumed. A general formula for the maximum available power is reviewed, along with assessments of the reduction if only partial fences are used, as would be required for navigational and ecological reasons. In typical situations, the maximum power obtainable may be achieved with a surprisingly small number of turbines, especially if allowance is made for the flow reduction caused by drag on the supporting structures of turbines which reduces the maximum power available. Finally, the flow through tidal turbines is compared with the cooling water demands of nuclear reactors generating the same power.