71 research outputs found

    Evaluation of two ultrasonic systems for analysis of porosity in ceramic

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    The Ultrasound Laboratory of the Nuclear Engineering Institute (LABUS / IEN) has developed an ultrasonic technique to measure porosity in nuclear fuel pellets (UO2). By difficulties related to the handling of UO2 pellets, Alumina (Al2O3) pellets have been used in preliminary tests, until a methodology for tests with pellets of UO2 could be defined. In a previous work, in which a contact ultrasonic technique was used, good results were obtained to measure the porosity of Alumina pellets. In the current studies, it was found that the frequency spectrum of an ultrasonic pulse is very sensitive to the porosity of the medium in which it propagates. In order to define the most appropriate experimental apparatus for using immersion technique in future tests, two ultrasonic systems, available in LABUS, which permit to work with the ultrasonic pulse in the frequency domain were evaluated . One system was the Explorer II (Matec INSTRUMENTS) and the other the ultrasonic pulse generator Epoch 4 Plus (Panametrics) coupled with an oscilloscope TDS 3032B (Tektronix). For this evaluation, several frequency spectra were obtained with the two equipment, by the passage of the ultrasonic wave in the same pellet of Alumina. This procedure was performed on four different days, on each day 12 ultrasonic signals were acquired, one signal every 10 minutes, with each apparatus. The results were compared and analyzed as regard the repeatability of the frequency spectra obtained

    Analysis of ultrasonic techniques for the characterization of microfiltration polymeric membranes

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    The use of polymeric membranes is extremely important in several industries such as nuclear, biotechnology, chemical and pharmaceutical. In the nuclear area, for instance, systems based on membrane separation technologies are currently being used in the treatment of radioactive liquid effluent, and new technologies using membranes are being developed at a great rate. The knowledge of the physical characteristics of these membranes, such as, pore size and the pore size distribution, is very important to the membranes separation processes. Only after these characteristics are known is it possible to determine the type and to choose a particular membrane for a specific application. In this work, two ultrasonic non destructive techniques were used to determine the porosity of membranes: pulse echo and transmission. A 25 MHz immersion transducer was used. Ultrasonic signals were acquired, for both techniques, after the ultrasonic waves passed through a microfiltration polymeric membrane of pore size of 0.45 ÎŒm and thickness of 180 ÎŒm. After the emitted ultrasonic signal crossed the membrane, the received signal brought several information on the influence of the membrane porosity in the standard signal of the ultrasonic wave. The ultrasonic signals were acquired in the time domain and changed to the frequency domain by application of the Fourier Fast Transform (FFT), thus generating the material frequency spectrum. For the pulse echo technique, the ultrasonic spectrum frequency changed after the ultrasonic wave crossed the membrane. With the transmission technique there was only a displacement of the ultrasonic signal at the time domain

    Planning oral health care using the sociodental approach and the index of family living conditions: a cross-sectional study in Brazilian adolescents.

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    BACKGROUND: Oral health care needs assessment is frequently restricted to clinical measures. Combining normative assessment, behavioural propensity, oral health-related quality of life and information of family living conditions may provide a better comprehensive approach of adolescent's oral health needs assessment. The aim of this study was to compare normative methods of dental caries need with the sociodental approach in 12-year-old adolescents according to family's living conditions in a deprived community in Brazil. In addition, dental caries need assessment using the normative method and the sociodental approach was compared between adolescents living in different living conditions. METHODS: A cross-sectional survey was conducted in the Manguinhos community in the city of Rio de Janeiro, Brazil. A weighted sample of 159 participants was randomly selected to represent the population of 2004 12-year-old adolescents. Socioeconomic characteristics and living conditions of the family were assessed using the Family Development Index (FDI). Oral health-related quality of life (OHRQoL) was assessed using the generic and CS-Child-OIDP, and adolescent's propensity to adopt oral health promoting behaviours was verified through interviews. Dental caries and treatment need were assessed normatively by clinical oral examinations (DMFT Index) and adolescents were classified into two groups (non severe or severe caries). The sociodental approach included clinical measures of caries, propensity to adopt oral health promoting behaviors and OHRQoL. Families were classified based on the FDI as 'not severe', 'severe' and 'very severe'. Measures of caries, OHRQoL and propensity outcomes were compared between FDI groups using Chi-square and Kruskal-Wallis tests. In addition, dental treatment needs using normative method and sociodental approach were compared for the whole sample and according to FDI groups. RESULTS: Dental caries, OHRQoL and lower propensity needs were positively associated with FDI severity. The percentages of adolescents with normative dental needs from families with 'very severe', 'severe' and 'not severe' FDI were 59.3, 48.4 and 17.2 % (P < 0.05). Using the sociodental approach, the treatment needs for the three FDI groups decreased to 8.8, 13.6 and 8.6 %, respectively (P < 0.05). CONCLUSIONS: Using a combination of sociodental approach and the index of family living conditions was useful for defining dental care priorities in adolescents living in deprived communities and can optimise the use of resources in dental services

    Expanding tropical forest monitoring into Dry Forests: The DRYFLOR protocol for permanent plots

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    This is the final version. Available on open access from Wiley via the DOI in this recordSocietal Impact Statement Understanding of tropical forests has been revolutionized by monitoring in permanent plots. Data from global plot networks have transformed our knowledge of forests’ diversity, function, contribution to global biogeochemical cycles, and sensitivity to climate change. Monitoring has thus far been concentrated in rain forests. Despite increasing appreciation of their threatened status, biodiversity, and importance to the global carbon cycle, monitoring in tropical dry forests is still in its infancy. We provide a protocol for permanent monitoring plots in tropical dry forests. Expanding monitoring into dry biomes is critical for overcoming the linked challenges of climate change, land use change, and the biodiversity crisis.Newton FundNatural Environment Research Council (NERC)Fundação de Amparo à Pesquisa do Estado de São PauloCYTE

    A Deep Insight into the Sialome of Rhodnius neglectus, a vector of chagas disease

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    Background Triatomines are hematophagous insects that act as vectors of Chagas disease. Rhodnius neglectus is one of these kissing bugs found, contributing to the transmission of this American trypanosomiasis. The saliva of hematophagous arthropods contains bioactive molecules responsible for counteracting host haemostatic, inflammatory, and immuneresponses. Methods/Principal Findings Next generation sequencing and mass spectrometry-based protein identification were performed to investigate the content of triatomine R. neglectus saliva.We deposited 4,230 coding DNA sequences (CDS) in GenBank. A set of 636 CDS of proteins of putative secretory nature was extracted from the assembled reads, 73 of them confirmed by proteomic analysis. The sialome of R. neglectus was characterized and serine protease transcripts detected. The presence of ubiquitous protein families was revealed, including lipocalins, serine protease inhibitors, and antigen-5. Metalloproteases, disintegrins, and odorant binding protein families were less abundant. Conclusions/Significance The data presented improve our understanding of hematophagous arthropod sialomes, and aid in understanding hematophagy and the complex interplay among vectors and their vertebrate hosts

    Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe

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    We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z∌0.03z\sim 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z∌0.6z\sim 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July
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