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Articoli di riviste sul tema "Imarad Imaging Systems LTD"
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Mitchell, Gregory S., Ruby K. Gill, David L. Boucher, Changqing Li e Simon R. Cherry. "In vivo Cerenkov luminescence imaging: a new tool for molecular imaging". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, n. 1955 (28 novembre 2011): 4605–19. http://dx.doi.org/10.1098/rsta.2011.0271.
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Cerenkov radiation is a phenomenon where optical photons are emitted when a charged particle moves faster than the speed of light for the medium in which it travels. Recently, we and others have discovered that measurable visible light due to the Cerenkov effect is produced in vivo following the administration of β-emitting radionuclides to small animals. Furthermore, the amounts of injected activity required to produce a detectable signal are consistent with small-animal molecular imaging applications. This surprising observation has led to the development of a new hybrid molecular imaging modality known as Cerenkov luminescence imaging (CLI), which allows the spatial distribution of biomolecules labelled with β-emitting radionuclides to be imaged in vivo using sensitive charge-coupled device cameras. We review the physics of Cerenkov radiation as it relates to molecular imaging, present simulation results for light intensity and spatial distribution, and show an example of CLI in a mouse cancer model. CLI allows many common radiotracers to be imaged in widely available in vivo optical imaging systems, and, more importantly, provides a pathway for directly imaging β − -emitting radionuclides that are being developed for therapeutic applications in cancer and that are not readily imaged by existing methods.
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Connolly, Christine. "High‐speed imaging investigations from Pixoft Diagnostic Imaging Ltd". Assembly Automation 26, n. 3 (luglio 2006): 184–87. http://dx.doi.org/10.1108/01445150610679696.
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Dorney, Timothy D., William W. Symes e Daniel M. Mittleman. "Multistatic Reflection Imaging with Terahertz Pulses". International Journal of High Speed Electronics and Systems 13, n. 02 (giugno 2003): 677–99. http://dx.doi.org/10.1142/s0129156403001855.
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Recent advances in the technique of terahertz time-domain spectroscopy have led to the development of the first fiber-coupled room-temperature broadband terahertz sources and detectors. The fiber coupling permits the repositioning of the emitter and receiver antennas without loss of temporal calibration or alignment, thus enabling multistatic imaging. We describe a new imaging method which exploits this new capability. This technique emulates the data collection and image processing procedures developed for geophysical prospecting. We use a migration procedure to solve the inverse problem; this permits us to reconstruct the location, shape, and refractive index of targets. We show examples for both metallic and dielectric model targets, and we perform velocity analysis on dielectric targets to estimate the refractive indices of imaged components. These results broaden the capabilities of terahertz imaging systems, and also demonstrate the viability of the THz system as a test bed for the exploration of new seismic processing methods.
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Gilley, Patrik, Ke Zhang, Neman Abdoli, Youkabed Sadri, Laura Adhikari, Kar-Ming Fung e Yuchen Qiu. "Development and Assessment of Multiple Illumination Color Fourier Ptychographic Microscopy for High Throughput Sample Digitization". Sensors 24, n. 14 (12 luglio 2024): 4505. http://dx.doi.org/10.3390/s24144505.
Testo completoAbstract (sommario):
In this study, we proposed a multiplexed color illumination strategy to improve the data acquisition efficiency of Fourier ptychography microscopy (FPM). Instead of sequentially lighting up one single channel LED, our method turns on multiple white light LEDs for each image acquisition via a color camera. Thus, each raw image contains multiplexed spectral information. An FPM prototype was developed, which was equipped with a 4×/0.13 NA objective lens to achieve a spatial resolution equivalent to that of a 20×/0.4 NA objective lens. Both two- and four-LED illumination patterns were designed and applied during the experiments. A USAF 1951 resolution target was first imaged under these illumination conditions, based on which MTF curves were generated to assess the corresponding imaging performance. Next, H&E tissue samples and analyzable metaphase chromosome cells were used to evaluate the clinical utility of our strategy. The results show that the single and multiplexed (two- or four-LED) illumination results achieved comparable imaging performance on all the three channels of the MTF curves. Meanwhile, the reconstructed tissue or cell images successfully retain the definition of cell nuclei and cytoplasm and can better preserve the cell edges as compared to the results from the conventional microscopes. This study initially validates the feasibility of multiplexed color illumination for the future development of high-throughput FPM scanning systems.
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Foroni, R., G. Gambraini, U. Danesi, M. Mauri, E. Pompilio, L. Pirola, A. Nicolato, P. Ferraresi e M. Gerosa. "New dosimetric approach for multidimensional dose evaluation in gamma knife radiosurgery". Journal of Neurosurgery 93, supplement_3 (dicembre 2000): 239–42. http://dx.doi.org/10.3171/jns.2000.93.supplement_3.0239.
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✓ During the past two decades, the progress in computerized treatment planning systems has led to more accurate imaging and therapy by using the gamma knife, especially with the smallest collimators (4 mm). However, the ionization chambers that have been used to calibrate the gamma knife are not useful with the smallest collimators because the chambers are too big compared with the irradiated volume. Therefore, it is important to develop more suitable dosimeters. This study proposes a new dosimeter method. The FriXyGel method proposed here is based on a phantom dosimeter, an acquisition chain, and dedicated software. This dosimeter uses an agarose gel into which a ferrous sulphate solution (Fricke solution) and a metal ion indicator (xylenol orange) are incorporated. The absorbed dose is detected through measurements of visible light transmission, imaged by means of a charge-coupled device camera provided with a suitable optical filter. Gel layers are imaged before and after irradiation, and the differences in light absorption are related to the absorbed dose. By choosing convenient thickness of gel layers and by building up a phantom with different gel slices, it is possible to obtain a three-dimensional (3D) representation of the absorbed dose. The final 3D representation is reached after several mathematical processes have been applied to the images. The first step identifies and reduces all factors that could alter the original data, such as nonuniformity in illumination. Then, after calibration procedures, it is possible to obtain absorbed dose values and to discover their 3D representation. This goal has been reached by developing appropriate software that performs all the calculations necessary for spatial representation routines and prompt comparison with theoretical calculations.
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Akter, Shirin, Rajada Khatun, S. M. Enamul Kabir, Ashrafun Nahar Monika, Md Fakhar Uddin, Md Mahfuzur Rahman e Mohammad Monjur Ahasan. "Dosimetric Verification of Computed Tomography (CT) Systems Using CTDI Phantom". Bangladesh Journal of Nuclear Medicine 26, n. 2 (23 giugno 2024): 172–76. http://dx.doi.org/10.3329/bjnm.v26i2.71488.
Testo completoAbstract (sommario):
Background: Computed tomography (CT) is a medical imaging modality that contributes widely over the world for the diagnosis of disease and for treatment planning in the radiotherapy department. The purpose of the study is to measure the accuracy of dose of CT System for quality treatment. Materials and Methods: The study was executed in a 16 slice SOMATOM Emotion CT Scanner of Delta Hospital Ltd. with Tube voltage 130 KV and Tube current 25 mA using Computed Tomography Dose Index (CTDI) phantom (CIRS) of MPD, Atomic Energy Centre, Dhaka. IBA pencil ionization chamber was used to measure the dose at different positions inside the CTDI phantom and data were collected using IBA MagicMax Universal software. The CT radiation doses were estimated using formalisms in the AAPM Report 96 and 111. Results: For the Adult Body Phantom Console displayed dose was 16.03 mGy and estimated dose was found as16.40 mGy. For the Adult Head Phantom, console displayed dose was 32.40 mGy and estimated dose was found as 34.60 mGy. Between the estimated and console displayed doses for Adult Body Phantom and Adult Head Phantom a deviation was realized of 2.3% and 6.8% respectively. Conclusion: Hence CTDI of the above mentioned machine comply with reference value within a tolerance of ± 20 % according to Food and Drug Administration (FDA). Bangladesh J. Nuclear Med. 26(2): 172-176, 2023
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Grothusen, John R. "Laser Doppler Imaging: Usefulness in Chronic Pain Medicine". Pain Physician 5;14, n. 5;9 (14 settembre 2011): 491–98. http://dx.doi.org/10.36076/ppj.2011/14/491.
Testo completoAbstract (sommario):
Sympathetic nervous system dysfunction is thought to be a factor in neuropathic pain conditions such as Complex Regional Pain Syndrome and in vascular conditions such as Raynaud’s phenomenon. Laser Doppler fluxmetry has been used as a fast non-invasive method to quantify changes in skin capillary blood flow which reflect activation of sympathetically mediated vasoconstriction of the arterioles that supply the capillaries. Studies of dynamic change of skin capillary blood flow with sympathetic activation such as cold or inspiratory gasp have generally used single point laser Doppler systems where the probe is in contact with the skin. The results are a single line tracing representing the capillary flow at a single point on the skin a few millimeters in diameter. Laser Doppler imaging (moorLDI laser Doppler imager, Moor Instruments Ltd.) allows for non-contact recording of skin blood flow of an area as large as 50 centimeters square with a resolution of 256 by 256 pixels and 4 milliseconds per pixel. Most work with laser Doppler imaging has studied changes that occur between successive scans. We have found it useful to look at changes that occur during a scan. In this way we obtain data that is comparable to the time resolution of single point laser Doppler methods, but with the larger spatial information that is available with laser Doppler imaging. We present a small series of case reports in which inspiratory gasp during laser Doppler imaging was able to provide quick, useful and unequivocal clinical information regarding the status of regional bilateral skin capillary response to sympathetic activation. This may be useful for distinguishing sympathetically mediated from sympathetically independent pain. We believe the methods described may provide the basis for future quantitative studies similar to those that use single point laser Doppler methods. Key words: Laser doppler, laser Doppler imaging, sympathetically maintained pain, Raynaud’s phenomen, complex regional pain syndrome
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Pransky, Joanne. "Dr Amit Goffer, co-founder at UPnRIDE, serial inventor and entrepreneur". Industrial Robot: An International Journal 45, n. 2 (19 marzo 2018): 175–80. http://dx.doi.org/10.1108/ir-01-2018-0009.
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Purpose The following article is a “Q&A interview” conducted by Joanne Pransky of Industrial Robot Journal as a method to impart the combined technological, business and personal experience of a prominent industry engineer-turned successful innovator and entrepreneur regarding the development of his inventions and the challenges he faced. This paper aims to discuss these issues. Design/methodology/approach The interviewee is Dr Amit Goffer, Chief Technology Officer and President at UPnRIDE Robotics Ltd., a startup that makes a wheeled robotic device for almost anyone who is unable to physically stand or walk. He served as Chief Executive Officer (until 2012) and President and Chief Technical Officer of ReWalk Robotics, a company he founded in 2001 (previously called Argo Medical Technologies Ltd). Prior to Argo/ReWalk, Dr Goffer served as the Founder at Odin Medical Technologies Ltd. (later acquired by Medtronic), President and Chief Executive Officer. As an accomplished inventor and serial entrepreneur of medical devices, Goffer describes how his education in school and in running his companies combined with his life experiences led to his breakthroughs. Findings Dr Amit Goffer completed BSc from Technion-Israel Institute of Technology, MSc from Tel-Aviv University, Israel, and PhD from Drexel University, Philadelphia, USA, all in electrical and computer engineering. After working for Elscint, a medical imaging company, Goffer started Odin Medical to provide real-time magnetic resonance imaging images for brain surgery. After a tragic accident confined him to a wheelchair, Goffer created ReWalk, a robotic exoskeleton that enables people with lower limb disabilities to stand, walk, ascend/descend stairs and more. He recently founded his latest company, UPnRIDE. Originality/value Dr Amit Goffer is highly regarded as a pioneer of the emerging exoskeleton industry. His invention and development of the ReWalk Robotics wearable exoskeleton has enabled so far hundreds of wheelchair users to walk again, and another estimated 500,000 could benefit from it. Despite Goffer not being able to use the ReWalk himself, as he is a quadriplegic, his greatest passion is to improve the disabled’s self-esteem and quality of life. ReWalk was the first commercially available exoskeleton in the USA. It was named “best invention” by Popular Science and Time magazines. ReWalk Robotics went public in 2014. In 2015, the US Veteran’s Administration announced they would provide ReWalks for all eligible veterans with spinal cord injuries. Goffer recently devised UPnRIDE as a new product, allowing millions of wheelchair users worldwide, including himself, full mobility in the standing position in almost any urban environment.
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Askari, Mohammad Sadegh, Sharon M. O'Rourke e Nicholas M. Holden. "A comparison of point and imaging visible-near infrared spectroscopy for determining soil organic carbon". Journal of Near Infrared Spectroscopy 26, n. 2 (aprile 2018): 133–46. http://dx.doi.org/10.1177/0967033518766668.
Testo completoAbstract (sommario):
This study evaluated whether the accuracy of soil organic carbon measurement by laboratory hyperspectral imaging can match that of standard point spectroscopy operating in the visible–near infrared. Hyperspectral imaging allows a greater amount of spectral information to be collected from the soil sample compared to standard spectroscopy, accounting for greater sample representation. A total of 375 representative Irish soils were scanned by two-point spectrometers (a Foss NIR Systems 6500 labelled S-1 and a Varian FT-IR 3100 labelled S-2) and two laboratory hyperspectral imaging systems (two push broom line-scanning hyperspectral imaging systems manufactured by DV optics and Spectral Imaging Ltd, respectively, labelled S-3 and S-4). The objectives were (a) to compare the predictive ability of spectral datasets for soil organic carbon prediction for each instrument evaluated and (b) to assess the impact of imposing a common wavelength range and spectral resolution on soil organic carbon model accuracy. These objectives examined the predictive ability of spectral datasets for soil organic carbon prediction based on optimal settings of each instrument in (a) and introduced a constraint in wavelength range and spectral resolution to achieve common settings for instruments in (b). Based on optimal settings for each instrument, the deviation (root-mean square error of prediction) from the best fit line between laboratory measured and predicted soil organic carbon, ranked the instruments as S-1 (26.3 g kg−1) < S-2 (29.4 g kg−1) < S-3 (34.3 g kg−1) < S-4 (41.1 g kg−1). The S-1 model outperformed in all partial least squares regression performance indicators, and across all spectral ranges, and produced the most favourable outcomes in means testing, variance testing and identification of significant variables. It is assumed that a larger wavelength range produced more accurate soil organic carbon predictions for S-1 and S-2. Under common instrument settings, the prediction accuracy for S-3 that was almost equal to S-1. It is concluded that under standard operating procedures, greater soil sample representation captured by hyperspectral imaging can equal the quality of the spectra from point spectroscopy. This result is important for the development of laboratory hyperspectral imaging for soil image analysis.
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Chiabrando, F., e L. Teppati Losè. "PERFORMANCE EVALUATION OF COTS UAV FOR ARCHITECTURAL HERITAGE DOCUMENTATION. A TEST ON S.GIULIANO CHAPEL IN SAVIGLIANO (CN) – ITALY". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W6 (23 agosto 2017): 77–84. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w6-77-2017.
Testo completoAbstract (sommario):
Even more the use of UAV platforms is a standard for images or videos acquisitions from an aerial point of view. According to the enormous growth of requests, we are assisting to an increasing of the production of COTS (Commercial off the Shelf) platforms and systems to answer to the market requirements. In this last years, different platforms have been developed and sell at low-medium cost and nowadays the offer of interesting systems is very large. One of the most important company that produce UAV and other imaging systems is the DJI (Dà-Jiāng Innovations Science and Technology Co., Ltd) founded in 2006 headquartered in Shenzhen – China. The platforms realized by the company range from low cost systems up to professional equipment, tailored for high resolution acquisitions useful for film maker purposes. According to the characteristics of the last developed low cost DJI platforms, the onboard sensors and the performance of the modern photogrammetric software based on Structure from Motion (SfM) algorithms, those systems are nowadays employed for performing 3D surveys starting from the small up to the large scale. <br><br> The present paper is aimed to test the characteristic in terms of image quality, flight operations, flight planning and accuracy evaluation of the final products of three COTS platforms realized by DJI: the Mavic Pro, the Phantom 4 and the Phantom 4 PRO. The test site chosen was the Chapel of San Giuliano in the municipality of Savigliano (Cuneo-Italy), a small church with two aisles dating back to the early eleventh century.
Libri sul tema "Imarad Imaging Systems LTD"
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Wells, S. Zenith Medical Systems Ltd Superix 180 digital imaging system. London: Medical Devices Agency, 1997.
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Lawinski, C. P. Zenith Medical Systems Ltd. Superix 180 digital imaging system. (London): (Medical Devices Agency), 1997.
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Harris, L. IGE Medical Systems Ltd Stenoscop 2 Series 9000 mobile C-arm digital imaging system. London: Department of Health, Medical Devices Agency, 1996.
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Lawinski, C. P. IGE Medical Systems Ltd Stenoscop 2 series 9000 mobile C-arm digital imaging system. London: Department of Health, Medical Devices Agency, 1996.
Cerca il testo completoCapitoli di libri sul tema "Imarad Imaging Systems LTD"
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"Benthic Habitats and the Effects of Fishing". In Benthic Habitats and the Effects of Fishing, a cura di Raymond E. Grizzle, Larry G. Ward, Jamie R. Adams, Semme J. Dijkstra e Brian Smith. American Fisheries Society, 2005. http://dx.doi.org/10.47886/9781888569605.ch13.
Testo completoAbstract (sommario):
<strong><em>Abstract. </em></strong>Populations of the eastern oyster <em>Crassostrea virginica </em>have been in long-term decline in most areas. A major hindrance to effective oyster management has been lack of a methodology for accurately and economically obtaining data on their distribution and abundance patterns. Here, we describe early results from studies aimed at development of a mapping and monitoring protocol involving acoustic techniques, underwater videography, and destructive sampling (excavated quadrats). Two subtidal reefs in Great Bay, New Hampshire, were mapped with side-scan sonar and with videography by systematically imaging multiple sampling cells in a grid covering the same areas. A single deployment was made in each cell, and a 5–10-s recording was made of a 0.25-m<sup>2</sup> area; the location of each image was determined using a differential global position system. A still image was produced for each of the cells and all (<em>n </em>= 40 or 44) were combined into a single photomontage overlaid onto a geo-referenced base map for each reef using ArcView geographic information system. Quadrat (0.25 m<sup>2</sup>) samples were excavated from 9 or 10 of the imaged areas on each reef, and all live oysters were counted and measured. Intercomparisons of the acoustic, video, and quadrat data suggest: (1) acoustic techniques and systematic videography can readily delimit the boundaries of oyster reefs; (2) systematic videography can yield quantitative data on shell densities and information on reef structure; and (3) some combination of acoustics, systematic videography, and destructive sampling can provide spatially detailed information on oyster reef characteristics.
Atti di convegni sul tema "Imarad Imaging Systems LTD"
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Periyasamy, Vijitha, Katherine Gisi e Manojit Pramanik. "Photoacoustic imaging of dental samples". In Optical Tomography and Spectroscopy. Washington, D.C.: Optica Publishing Group, 2024. http://dx.doi.org/10.1364/ots.2024.otu3d.2.
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We discuss the photoacoustic computed tomography (PACT) imaging of teeth using a clinical system which has light emitting diode (LED) as an illumination source. It is demonstrated that the caries and demineralization can be imaged using LED-PACT.
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Pehlke, Trent, Greer Simpson, Andrew Roberts, Tamara Maxwell e Julia Chu. "High-Resolution Acoustic Imaging Deployed for Mapping Permanent Fiber Optic Lines". In SPE Hydraulic Fracturing Technology Conference and Exhibition. SPE, 2024. http://dx.doi.org/10.2118/217819-ms.
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Abstract High-resolution acoustic imaging technology has been developed and deployed to map the downhole location and orientation of fiber optic lines in unconventional oil and gas and carbon capture wells. Fiber optic installations are long term monitoring solutions providing continuous measurement of temperature, sound, or strain. These fiber lines provide significant insight into the operation and optimization of downhole assets but require a large capital investment, typically upwards of a million dollars. By accurately mapping fiber optic lines, operators can prevent damaging or perforating through these costly systems during completion and production operations. High-resolution acoustic imaging technology allows operators to directly locate and map in-situ fiber optic systems at logging speeds up to ten times faster, with high accuracy, and more efficiently than legacy technologies by overcoming the requirement to install additional costly detection components. The unique sensor probe employs a circumferential array design, comprised of up to 512 individual elements which are electronically controlled from advanced imaging software. The integration of machine vision algorithms has led to a 100% success rate at detecting, orientating, and mapping of fiber optic lines to prevent damaging these costly and critical monitoring installations. Through a series of validation tests and field applications, this paper details how the solid-state imaging probe was used to identify the submillimetric indentations made at each fiber clamps installation. These contact points indicate the depth and phase orientation of each clamp in a well, enabling the generation of a high-resolution fiber optics system map. While legacy ultrasonic tools rely on a direct reflection principle, this novel, intra-steel imaging technology measures diffuse acoustic reflections at any point on, or inside of, the casing steel. Diffuse reflections are highly sensitive to indentations and markings on the casing surfaces; this removes the legacy-technology requirements for excessively slow logging speeds and the installation of costly steel detection bars. Following successful validation testing, this technology was field deployed and successfully located, oriented, and mapped all the fiber optic clamps ahead of perforating the casing of a carbon capture well. The platform imaged and mapped over 2,060 clamp contact points with a sub-radian azimuthal or phase resolution. In addition to this, high- resolution acoustics have shown fiber optic systems wrap around the casing circumference multiple times, highlighting the inability for fiber optic systems to be accurately installed and oriented. Using this dataset, the operator effectively executed subsequent perforation activities without damaging the fiber optic lines used to monitor the well and reservoir.
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Haines, Harvey, Lars Hörchens e Jasper Schouten. "Adaptive Ultrasonic Imaging of Electric Resistance Welded Pipeline Seams". In 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78189.
Testo completoAbstract (sommario):
Imaging techniques using full matrix capture (FMC) ultrasonic NDE are well suited for in-service examination of electric resistance welded (ERW) pipe seams. We have been involved in developing an imagine technique since 2013 and presented results from Phase I at IPC in 2016 showing the system capable of detecting seam weld and SCC flaws and determining their orientation. The advantages over other methods such as phased array (PA) is the ability to image the flaw surface in addition to the flaw tip and corners where the flaw intersects the pipeline surface. This improves the ability to determine flaw orientation for discrimination of different types or crack-like features. The system produces UT images by overlaying multiple modes using reflections off the ID and OD pipe surface for ultrasonic illumination of the weld area from different directions. Using multiple modes produces a reflection off features regardless of flaw orientation from at least one of the modes. A complementary mode can then be used to size each feature by detecting the tips or ends of the feature from lower amplitude diffraction signals. Phase I used a model which assumed a cylindrical pipe shape. Real world use of this technique found limitations when pipe deviated from the assumed cylindrical shape such as severe offset plate edges, flat spots which can be the result of poor crimping adjacent the seam weld, or thickening of the seam caused by post weld heat treatment. In Phase II a need for reduced sizing error led to improved calibration and more advanced processing. To compensate for the non-perfect nature of real pipe, a new adaptive IWEX technique was developed to improve focusing and alignment of the various modes using the actual geometry to construct better focusing laws. First the OD and ID surfaces are imaged and the resulting surfaces are used to construct focusing laws which adapt to changes in the OD and ID surfaces. Results are better aligned UT images with the ability to image complex flaws with changes in orientation, and the ability to discriminate complex flaws from multiple small flaws in the pipe. Results show improvements in pipe with the greatest improvements in pipe with the largest deviations from a cylindrical shape.
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Torres, J., A. Perdones, A. Garcia e F. J. Diez. "Imaging Measurements in Nano-Particle Enhanced Spray Cooling". In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-31072.
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Thermal control is a major constraint in spacecraft development as increased demand on electronics performance requires large heat dissipation from smaller surfaces which has led to increased challenges for thermal control. Spray cooling has a great amount of application in industrial processes as a heat removal method. It is thought to be the future in thermal management systems in space because of its capability for ‘close’ and accurate control of heat removal. Spray cooling is based on phase change heat transfer generating high heat transfer rates for low superheats. This last term is used to describe the difference in temperature between the heated surface and the cooling fluid. When the temperature of the surface to be cooled rises above the saturation temperature of the fluid splashed to the surface, a phase change occurs at the solid liquid interface during the boiling regime. However, the most interesting phase (regime) is the nucleating boiling where the critical heat flux, CHF, is reached. The CHF is then achieved due to the vapor generation is such as great that the liquid cannot still be in contact with the surface. Thus the heat is transferred through the vapor if there is not enough cold fluid. The thermal conductivity of vapor is lower and so the efficient of the cooling process. This turns out in a decrease on heat flux. Nowadays it is being taken more into account nanofluids as a technique capable of enhancing heat transfer. Nanofluids, a mix of nano-size particles in a base fluid, have been found to have a very high thermal conductivity as compared to the base fluid. In You et al., 2003; Kim et al., 2004a; Moreno et al., 2005 water was used with various Al2O3 particle concentration in a flat plate nucleate pool boiling system. They came across with no change in the heat transfer coefficient but a dramatic enhancement in CHF. They also found that high concentrations can degrade nucleate boiling. The aim of this project is study the effects of spray cooling with suspended nano-particles as an enhanced method for heat transfer removal. The working fluid was water with different concentrations of alumina-oxide particles added. The alumina oxide particles were supplied by Nanophase Technologies (Nano Tek® Alumina Oxide AL-01000-003-025) which had a mean diameter of 60 nm. Three different concentrations were used and the following: .5 g/L, 1 g/L, 2 g/L. Since clumping of particles can affect the heat transfer properties of the droplets, the solution was placed on inside an ultrasonic bath and left there for at least 24 hrs and immediately used in the experiments. Two nozzles were used in this experiment to study a wide range of sauter diameter of droplets. The experiment was carried out using three experimental techniques which looked into different characteristics of spray cooling. In the first mode, the fluid was sprayed onto a copper block heater surface while it was imaged with a high speed camera and synchronized with a high speed Nd-YAG laser. 9 thermocouples were positioned inside the copper block heater, as seen on Figure 1, to measure critical heat flux, while a camera was used to record different impact properties and the influence of nano-particles. Some of these properties were pool buildup size, spread, and duration of pool. For the second imaging technique, the spray on the heated surface was also considered to be an impinging jet, so to visualize the flow of this jet and how the heated surface affected it, PIV (Particle Image Velocimetry) was used in the study. A third imaging technique was used to study the droplet behavior when in contact with a heated surface. A transparent glass heater made of aluminum silicate glass and coated with an ITO (indium tin oxide) film was used as the heater. The size of the drops had an average diameter of 2.38 mm. When compared to the copper block study, this method allows images to be taken from directly below the clear glass heater. Furthermore, these images allow for a clear edge detection of drops as they spread on the surface and what characteristics they develop when the droplets have different concentrations of nanoparticles, as seen on Figure 2. The experiment used a pulsed laser to provide the background illumination. This project is a continuing research project.
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Hämäläinen, E., N. Kriikka e G. Barbezat. "On-line Optical Diagnostics of a Rotating Internal Diameter Plasma Spray Gun Used for Coating of Cylinder Bores in Automotive Industry". In ITSC2003, a cura di Basil R. Marple e Christian Moreau. ASM International, 2003. http://dx.doi.org/10.31399/asm.cp.itsc2003p1249.
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Abstract Coating of cylinder bores using plasma spraying is a growing application of thermal spraying in automotive industry. The Sulzer Metco RotaPlasma manipulator provides continuous rotation of the internal diameter plasma gun and enables a cost-efficient and reliable coating of the cylinder blocks. The development towards more advanced quality control systems and closed-loop spray control systems requires an on-line measurement of the most important particle and spray parameters such as particle temperature, velocity and flux. However, the small dimensions of the plasma plume of an internal diameter spray gun together with the rotation of the gun makes the measurement difficult, if not impossible, for many traditional diagnostics equipment. In this work, SprayWatch, an imaging CCD camera based diagnostics system from Oseir Ltd. was used for measuring particle and spray parameters during the rotation of an internal diameter plasma spray gun. The results show that the SprayWatch camera system is a promising tool for both development and production monitoring of cylinder bore coating process, as well as for realising a closed-loop spray control system.
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Närväinen, Johanna, Juha Kortelainen, Timo Urhemaa, Mikko Saajanlehto, Kari Bäckman e Johan Plomp. "HealthGate: unobtrusive home monitoring of vital signs, weight and mobility of the elderly". In 14th International Conference on Applied Human Factors and Ergonomics (AHFE 2023). AHFE International, 2023. http://dx.doi.org/10.54941/ahfe1003472.
Testo completoAbstract (sommario):
This paper will discuss the feasibility of a monitoring setup HealthGate, designed to monitor the mobility, vital signs, and weight of an elderly person living in her own apartment. The versatile sensor setup will allow more comprehensive insights than what is currently available. Continuous home monitoring will enable early interventions and actions in e.g. suspected dehydration, mobility problems, and non-optimal or missed medication. The data can be used to form indices of e.g. frailty and sleep quality, to detect changes in health and behavior, and to alert the person, relatives or caregivers of detected and impending problems. Instead of interaction with the user, the setup seeks total unobtrusiveness: invisible or integrated sensors as well as automated measurements and data transmission. This is crucial with persons suffering from severe cognitive impairment: the operation does not rely on user actions and the setup is safe from a curious user. On the other hand, tailored reports can be provided to people who can and want to investigate their own status. The custom-made monitoring system uses three sensor types: a mm-range imaging FMCW radar (1), a seat foil sensor (2), and a novel four-element weight sensor array. The seat and weight sensors are positioned in a favorite armchair and the radar cabinet faces the chair, typically positioned next to the TV. The key events from which the data are recorded are the transitions to and from the chair and the moments sitting still in the in, typically watching TV. The system will monitor heart and breathing rate (both radar and seat foil), weight, and dynamic weight distribution across the sensors under the legs of the chair, as well as movement at and near the chair (radar). Sleep is monitored using a commercial sleep sensor (VTracker 2.0, eLive Ecosystem Ltd., Finland) placed underneath the topping mattress. As the chairs used in individual homes will vary making inter-subject comparisons more difficult, during each home monitoring period, the participants will also perform a guided sitting, standing-up and walking protocol using a similar setup but with a test chair. The 25 participants are residents of a senior community, living independently in their rental apartments but using home care services. The data are collected during a series of two two-week monitoring periods, five participants at a time, starting in November 2022. We will describe the setup and data collection solution as well as show the first multisensor data comparisons and the proposals for characteristic mobility parameters for a sit down - stand up sequence and walk. The quality, reliability and limits of the biosignals and movement parameters derived from the radar data will be discussed. The data will be compared to standard measures of frailty, collected in a controlled test session, consisting of grip force, walking speed, timed sit down – stand up, and agility tests, as well as the frailty index (3) computed from the interRAI-HC assessments collected bi-annually. The daily patterns, biosignal data and daily weight variation will be compared against sleep data and interview data on acute illnesses and other conditions influencing behavior and well-being. Finally, the usability and acceptability of the setup are discussed, based on the interview data collected from the participants and home care nurses.(1) M. Mercuri et al., (2016). Biomedical wireless radar sensor network for indoor emergency situations detection and vital signs monitoring. IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems (BioWireleSS), pp. 32-35(2) Anttonen, J., & Surakka, V. (2005, April). Emotions and heart rate while sitting on a chair. In Proceedings of the SIGCHI conference on Human factors in computing systems (pp. 491-499).(3) Faller JW, et al. (2019) Instruments for the detection of frailty syndrome in older adults: A systematic review. PLOS ONE 14(4): e0216166