13,528 research outputs found
K X-Ray Energies and Transition Probabilities for He-, Li- and Be-like Praseodymium ions
Theoretical transition energies and probabilities for He-, Li- and Be-like
Praseodymium ions are calculated in the framework of the multi-configuration
Dirac-Fock method (MCDF), including QED corrections. These calculated values
are compared to recent experimental data obtained in the Livermore SuperEBIT
electron beam ion trap facility
Validation of a compact microwave imaging system for bone fracture detection
This work presents a systematic evaluation of the effectiveness of an air-operated microwave imaging (MWI) system for detection of arbitrarily oriented thin fractures in superficial bones, like the tibia. This includes the proposal of a new compact, portable setup where a single Vivaldi antenna performs a semi-cylindrical scan of the limb. The antenna is operated in monostatic radar mode, near the skin but without contact, thus ensuring hygiene and patient comfort during the exam. The image is reconstructed using a wave-migration algorithm in the frequency domain combined with an adaptative algorithm based on singular value decomposition to remove the skin artifact, dealing with non-uniform bone profile and tissue cover. The study investigates the system resolution, the robustness of the method to the uncertainty of the permittivity and thickness of the involved tested tissues, as well as the robustness to involuntary patient movement. The experimental validation was performed for the first time on an integral ex-vivo animal leg, with all tissues present, including skin and fur. It confirmed both the effectiveness of the method, and the feasibility of the setup.info:eu-repo/semantics/publishedVersio
Feasibility of bone fracture detection using microwave imaging
This paper studies the feasibility of Microwave Imaging (MWI) for detection of fractures in superficial bones like the tibia, using a simple and practical setup. First-responders could use it for fast preliminary diagnosis in emergency locations, where X-Rays are not available. It may prove valuable also for cases where X-ray are not recommended, e.g., length pregnant women or children. The method is inspired on the synthetic aperture radar technique. A single Vivaldi antenna is used to linearly scan the bone in the 8.3-11.1 GHz frequency range and collect the scattered fields. The system is operated in air, without the need for impractical impedance-matching immersion liquids. The image is reconstructed using a Kirchhoff migration algorithm. A Singular Value Decomposition (SVD) strategy is used to remove skin and background artifacts. To test this technique, a set of full-wave simulations and experiments were conducted on a multilayer phantom and on an ex-vivo animal bone. Results show that the system can detect and locate bone transverse fractures as small as 1 mm width and 13 mm deep, even when the bone is wrapped by 2 mm thick skin.info:eu-repo/semantics/publishedVersio
Experimental evaluation of thin bone fracture detection using microwave imaging
Microwave imaging is a promising candidate modality for the detection of fractures in superficial bones. We propose a simple dedicated experimental setup and use it to evaluate experimentally the feasibility of detection and location of thin transversal fractures in an animal bone. A single small Vivaldi antenna scans the bone along its length in two longitudinal planes, and collects the monostatic scattered fields in the 8.3-11.1 GHz frequency range. The image is reconstructed using a wave migration algorithm. Tests were carried on an ex-vivo animal leg bone with an induced transversal fracture. The results showed that transversal bone fractures can be detected down to 0.35 mm thickness. The system is attractive for a practical application because it is contactless, operated in air, non-ionizing, simple and comfortable for the patient. It can be used e.g. by first responders in the field, or in low-income settings.info:eu-repo/semantics/acceptedVersio
Métodos de detecção de fusarium em sementes de pupunheira (Bactris gasipaes).
Suplemento. Edição do 45º Congresso Brasileiro de Fitopatologia, 2012, Manaus. Micologia. Resumo 207
Application of a CdTe Detector for Measurements of Mammographic X-ray Spectra
This work aims to characterize mammographic x-ray beams incident and transmitted by breast phantoms (from 0 to 45 mm) composed from known proportion of glandular and adipose tissue-equivalent materials. This study was performed for mammographic x-ray beams generated by a mammography equipment using different target/filter combinations (Mo/Mo, Mo/Rh and W/Rh). It was studied the modification of spectra shape of the beams transmitted through different thicknesses of these materials. It was also evaluated the penetrability of these transmitted beams by its correlations to the HVL, which were experimentally estimated and derived from the x-ray spectra measured using a spectrometry system with a CdTe detector. The x-ray spectra transmitted by the phantom with higher density presented lower intensity than those transmitted by those with lower density, as expected. The differences between the HVL values derived from the spectra and those estimated using air kerma measurements are lesser than 6% for about 88% of the spectra measured in this work. The expected spectra variations with phantom thickness, revealed by the measured transmitted x-ray spectra, were also confirmed by HVL measurements and agree with the estimated attenuation curves.The motivation of the study was related to the robustness of the spectra as a descriptor of radiation beams and the possibility of using these transmitted spectra for dose assessment related to mammographic procedures. We can conclude that developed method is able to characterize mammographic x-ray beams making it possible the use of this kind of data for dose assessment in mammography
Self-reported dermal effects of hand sanitisers in industrial workers
Artigo publicado em: Proceedings Book of the SHO2023. https://books.fe.up.pt/index.php/feup/catalog/view/978-989-54863-4-2/332/426Background: During COVID-19 pandemic, preventing the virus spread was extremely important to reduce the overall
burden of the disease, to maintain the companies running and to remain safe. WHO recommended physical distances,
appropriate use of personal protective equipment and hand hygiene practices to reduce the spread. Hand hygiene practice
by using alcohol-based hand sanitisers was generalized in all sectors of activity, including those with no previous need to
implement preventive measures against biological risks. Objective: The aim of this study was to obtain self-reported data
on hand hygiene habits and perceived symptomatology regarding skin health effects associated with skin exposure to
alcohol-based hand sanitisers of industrial workers during COVID-19 pandemic. Method: Between November 2021 and
April 2022, a questionnaire-based descriptive cross-sectional study was conducted using 97 study participants. Results:
The reported information on hands sanitisers used show that most of the participants at work, use the hand sanitizer
provided by the company a alcoholic solution of 2-propanol 70%. Nearly half of the workers disinfected their hands
more than 3 times per day, but at work, there was a concern to also disinfect wrists and forearms. Self-reported dermal
effects show that half of the participants noticed skin dryness with the increased use of hand sanitisers. Application: The
novelty of this work is posed by the type of sample under study (industrial rather than hospital context) which allow
gathering data to build knowledge in this field and to develop guidelines of good practices on how to make adequate
disinfection and to promote skin health in industrial settings.info:eu-repo/semantics/publishedVersio
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