Optimization of Photoelastic Properties and Stress Relief of Small-Sized Polycarbonate Disks for Granular Material Photoelastic Tests

The development of photoelastic tests was strongly enhanced by appearance of polycarbonate, hich turned out to be an excellent photoelastic material. In order to obtain small polycarbonate particles applicable for granular material photoelastic tests, small-diameter transparent cylindrical disks are cut from a polycarbonate plate preliminarily subjected to annealing, in order to provide stress relief. The plate-cutting and annealing regimes are optimized by the comprehensive analysis of mechanical and photoelastic properties of polycarbonate disks of various diameters and constant height of 5 mm. The resulting stress-strain photoelastic visualizations and material fringe patterns are analyzed, in order to verify the effectiveness of the proposed material processing and annealing regimes.Поликарбонат является оптимальным фотоупругим материалом для проведения механических испытаний методом фотоупругости. Для получения небольших частиц поликарбоната, применяемых при фотоупругих испытаниях гранулированного материала, из поликарбонатной пластины, предварительно подвергнутой отжигу для релаксации остаточных напряжений, вырезаются прозрачные цилиндрические диски малого диаметра. Режимы резки и отжига оптимизированы в результате анализа механических и фотоупругих свойств поликарбонатных дисков разного диаметра и постоянной высоты (5 мм). Анализ фотоупругих характеристик напряженно-деформированного состояния дисков и изохром подтвердил высокую эффективность предлагаемых режимов обработки и отжига для данного материала.Полікарбонат є оптимальним фотопружним матеріалом для проведення механічних випробувань методом фотопружності. Для отримання невеликих частинок полікарбонату, що використовуються при фотопружних випробуваннях гранульованого матер іалу, з полікарбонатної пластини, яку попереднью піддавали відпалу для релаксації залишкових напружень, вирізали прозорі циліндричні диски малого діаметра. Режими різання і відпалу оптимізовано в результаті аналізу механічних і фотопружних властивостей полікарбонатних дисків різного діаметра і постійної висоти (5 мм). Аналіз фотопружних характеристик напружено-деформованого стану дисків і ізохром підтвердив високу ефективність запропонованих режимів обробки і відпалу для даного матеріалу

3D in Vitro Ultrasound Super-Resolution Imaging Using a Clinical System

© 2018 IEEE. Assessment of complex and disordered tumour vasculature requires full 3D visualization. Ultrasound super-resolution techniques are able to image microvascular structure and flow beyond the diffraction limit. Existing demonstrations have been predominantly 2D, where the elevational resolution remains restricted to around the millimeter range, while 3D demonstrations have either used mechanical scanning, or have required customized or state-of-the-art research systems to achieve true super-resolution in the third dimension. In this study, 3D super-resolution and velocity tracking is demonstrated in vitro using an ultrasound imaging system currently available in the clinic. This was performed at 1.25 MHz transmit frequency, with a frame rate of 54 Hz in contrast enhanced imaging mode. Three-dimensional super-resolved volumetric imaging of a twisted micro-vessel phantom was demonstrated at 3.5 cm depth, where between 66-70% of localizations where estimated to fall within the vessel internal diameter. Demonstration of 3D ultrasound super-resolution using a system currently available in the clinic demonstrates a fast route for clinical translation and application. In the future, 3D localization using microbubble signal onset could allow considerably improved microvascular visualization to aid early disease detection, diagnosis, and intervention for micro-vascular related diseases like cancer

3-D Motion Correction for Volumetric Super-Resolution Ultrasound Imaging

© 2018 IEEE. Motion during image acquisition can cause image degradation in all medical imaging modalities. This is particularly relevant in 2-D ultrasound imaging, since out-of-plane motion can only be compensated for movements smaller than elevational beamwidth of the transducer. Localization based super-resolution imaging creates even a more challenging motion correction task due to the requirement of a high number of acquisitions to form a single super-resolved frame. In this study, an extension of two-stage motion correction method is proposed for 3-D motion correction. Motion estimation was performed on high volumetric rate ultrasound acquisitions with a handheld probe. The capability of the proposed method was demonstrated with a 3-D microvascular flow simulation to compensate for handheld probe motion. Results showed that two-stage motion correction method reduced the average localization error from 136 to 18 μm

The prevalence of mild cognitive impairment in diverse geographical and ethnocultural regions: The COSMIC Collaboration

Background Changes in criteria and differences in populations studied and methodology have produced a wide range of prevalence estimates for mild cognitive impairment (MCI). Methods Uniform criteria were applied to harmonized data from 11 studies from USA, Europe, Asia and Australia, and MCI prevalence estimates determined using three separate definitions of cognitive impairment. Results The published range of MCI prevalence estimates was 5.0%-36.7%. This was reduced with all cognitive impairment definitions: performance in the bottom 6.681% (3.2%-10.8%); Clinical Dementia Rating of 0.5 (1.8%-14.9%); Mini-Mental State Examination score of 24-27 (2.1%-20.7%). Prevalences using the first definition were 5.9% overall, and increased with age (P < .001) but were unaffected by sex or the main races/ethnicities investigated (Whites and Chinese). Not completing high school increased the likelihood of MCI (P = .01). Conclusion Applying uniform criteria to harmonized data greatly reduced the variation in MCI prevalence internationally

A Computational System for Generating and Evolving Building Designs

This paper describes a generative evolutionary design system that aims to fulfil two key requirements: customisability and scalability. Customisability is required in order to allow the design team to incorporate personalised and idiosyncratic rules and representations. Scalability is required in order to allow large complex designs to be generated and evolved without performance being adversely affected. In order to fulfil these requirements, a computational architecture has been developed that differs significantly from existing evolutionary systems. In order to verify the feasibility of the this architecture, the generative process capable of creating three-dimensional building models has been implemented and demonstrated

Generating-predicting soup: a conceptual framework for a design environment

A framework for the development of a computational environment that supports generative design is proposed. This environment is referred to as a generating-predicting soup. This paper discusses such an environment at a conceptual level. The research focuses on the architecture, engineering, construction, and facilities management (AEC/FM) domain. The general framework is however applicable to many design domains.

A Constraint Based Generative System for Floor Layouts

This paper presents the current study of using a constraint based approach to solve floor layout problems. Nonlinear programming technique is used for the solution searching. This paper presents the authors'attempt to improve the nonlinear programming techniques for floor layout problems. Unlike most nonlinear programming systems, multiple optimized solutions can be provided with this system. The process of solving a layout problem, from constraint specification to solution searching, is described in detail. A case study is given in the last section before the conclusions to illustrate how the proposed model works

Towards a Generative System for Intelligent Design Support

In the development of intelligent computer aided design systems, three important issues need to considered. These issues are: how to support the generation of product concepts using evolutionary computation techniques, how to use intelligent databases and constraint management systems for detailed exploration of product embodiment, and how to integrate rapid prototyping facilities for product evaluation. In this paper, we present a brief review of knowledge based design and evolutionary design and discuss ways of integrating both in the development of a generative design system. Based on this review, we present the model and its applications of a generative design system utilizing a number of AI and evolutionary computation techniques. This generative design model is intended to provide a generic computational framework for the development of intelligent design support systems

Fast Acoustic Wave Sparsely Activated Localization Microscopy (Fast-AWSALM) Using Octafluoropropane N Anodroplets

© 2018 IEEE. A crucial challenge in the application of ultrasound super-resolution imaging using microbubbles to the clinic is the long acquisition time together with the motion during the data acquisition. In this study, fast acoustic wave sparsely activated localization microscopy (fast-A WSALM)is developed to simultaneously image, activate and deactivate octafluoropropane nanodroplets during high-frame-rate planewave ultrasound imaging to achieve ultrasound super-resolution images on a sub-second timescale. This work demonstrates in vitro fast-A Wsalmof a non-flow 200-micron-tube phantom. Firstly, experimental results show that the octafluoropropane nanodroplets can be activated by the plane-wave pulses, whereas acoustic droplet vaporization has only been achieved using focused single element transducers or linear-array probes with focus-wave transmission in previous literature. The activation of nanodroplets via plane-waves without the need of using focused-transmit waves enables a faster imaging and activation acquisition. Second, the results show the fast-AWSALM can give a better estimation of the tube diameter (190 um)where standard B-mode ultrasound image cannot (550 um), In summary, this study demonstrates the potential of fast-A WSALM, a super-resolution techniques using nanodroplets, which can generate super-resolution images in milliseconds and does not require flow or a precise control of contrast agent concentration

Object-oriented simulation of behaviour in design support

Paper presented at 4th UNB Artificial Intelligence Symposium, 20-21 September 1991 at Fredericton, New Brunswick (CA)Available from British Library Document Supply Centre- DSC:3511.638(EU-DAI-RP--570) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo