444 research outputs found
Análise do efeito da adição de fibras de polipropileno na resistência de aderência à tração em argamassa de revestimento
Artigo submetido ao Curso de Engenharia Civil da UNESC - como requisito parcial para obtenção do Título de Engenheiro Civil.O presente trabalho apresenta o estudo realizado em argamassas de revestimento com adição de fibras de polipropileno, em diferentes teores, a fim de verificar a influência quanto à resistência de aderência com o substrato, bem como a resistência à tração na flexão e na compressão. Para tal, utilizou-se argamassa no traço de 1:5, sendo introduzidas fibras de polipropileno nos teores 500g/m³, 1000g/m³ e 1500g/m³. Foi verificado com a produção dos compósitos que em função do aumento do teor de fibras há o aumento da relação a/c, para que o índice de consistência se mantenha constante. Com a aplicação da argamassa nos blocos cerâmicos, foi possível observar melhoria na trabalhabilidade para maiores teores de fibras entanto, estes maiores teores de fibras resultam na redução da resistência para os ensaios de tração e compressão, devido ao teor de ar incorporado se elevar. Para o ensaio de aderência à tração, os acréscimos de fibras na argamassa de revestimento levaram ao aumento da resistência. Os resultados dos ensaios indicaram que as argamassas produzidas com adição de fibras de polipropileno são favorecidas quanto ao comportamento mecânico de aderência à tração
Adsorption of emerging pollutants with different biochar adsorbents
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International Benchmark Activity in the Field of Sodium Fast Reactors
Global interest in fast reactors has been growing since their inception in 1960 because they can provide efficient, safe, and sustainable energy. Their closed fuel cycle can support long-term nuclear power development as part of the world’s future energy mix and decrease the burden of nuclear waste. In addition to current fast reactors construction projects, several countries are engaged in intense R&D and innovation programs for the development of innovative, or Generation IV, fast reactor concepts. Within this framework, NINE is very actively participating in various Coordinated Research Projects (CRPs) organized by the IAEA, aimed at improving Member States’ fast reactor analytical simulation capabilities and international qualification through code-to-code comparison, as well as experimental validation on mock-up experiment results of codes currently employed in the field of fast reactors. The first CRP was focused on the benchmark analysis of Experimental Breeder Reactor II (EBR-II) Shutdown Heat Removal Test (SHRT-17), protected loss-of-flow transient, which ended in the 2017 with the publication of the IAEA-TECDOC-1819. In the framework of this project, the NINE Validation Process– developed in the framework of NEMM (NINE Evaluation Model Methodology) – has been proposed and adopted by most of the organizations to support the interpretation of the results calculated by the CRP participants and the understanding of the reasons for differences between the participants’ simulation results and the experimental data. A second project regards the CRP focused on benchmark analysis of one of the unprotected passive safety demonstration tests performed at the Fast Flux Test Facility (FFTF), the Loss of Flow Without Scram (LOFWOS) Test #13, started in 2018. A detailed nodalization has been developed by NINE following its nodalization techniques and the NINE validation procedure has been adopted to validate the Simulation Model (SM) against the experimental data of the selected test. The third activity deals with the neutronics benchmark of China Experimental Fast Reactor (CEFR) Start-Up Tests, a CRP proposed by the China Institute of Atomic Energy (CIAE) launched in 2018 the main objective of which is to improve the understanding of the start-up of a SFR and to validate the fast reactor analysis computer codes against CEFR experimental data. A series of start-up tests have been analyzed in this benchmark and NINE also proposed and organized a further work package focused on the sensitivity and uncertainty analysis of the first criticality test. The present chapter intends to summarize the results achieved using the codes currently employed in the field of fast reactor in the framework of international projects and benchmarks in which NINE was involved and emphasize how the application of developed procedures allows to validate the SM results and validate the computer codes against experimental data
Dual Source Photon-Counting Computed Tomography-Part II: Clinical Overview of Neurovascular Applications
Photon-counting detector (PCD) is a novel computed tomography detector technology (photon-counting computed tomography-PCCT) that presents many advantages in the neurovascular field, such as increased spatial resolution, reduced radiation exposure, and optimization of the use of contrast agents and material decomposition. In this overview of the existing literature on PCCT, we describe the physical principles, the advantages and the disadvantages of conventional energy integrating detectors and PCDs, and finally, we discuss the applications of the PCD, focusing specifically on its implementation in the neurovascular field
Dual-Source Photon-Counting Computed Tomography-Part I: Clinical Overview of Cardiac CT and Coronary CT Angiography Applications
The photon-counting detector (PCD) is a new computed tomography detector technology (photon-counting computed tomography, PCCT) that provides substantial benefits for cardiac and coronary artery imaging. Compared with conventional CT, PCCT has multi-energy capability, increased spatial resolution and soft tissue contrast with near-null electronic noise, reduced radiation exposure, and optimization of the use of contrast agents. This new technology promises to overcome several limitations of traditional cardiac and coronary CT angiography (CCT/CCTA) including reduction in blooming artifacts in heavy calcified coronary plaques or beam-hardening artifacts in patients with coronary stents, and a more precise assessment of the degree of stenosis and plaque characteristic thanks to its better spatial resolution. Another potential application of PCCT is the use of a double-contrast agent to characterize myocardial tissue. In this current overview of the existing PCCT literature, we describe the strengths, limitations, recent applications, and promising developments of employing PCCT technology in CCT
Dual-Source Photon-Counting Computed Tomography-Part III: Clinical Overview of Vascular Applications beyond Cardiac and Neuro Imaging
Photon-counting computed tomography (PCCT) is an emerging technology that is expected to radically change clinical CT imaging. PCCT offers several advantages over conventional CT, which can be combined to improve and expand the diagnostic possibilities of CT angiography. After a brief description of the PCCT technology and its main advantages we will discuss the new opportunities brought about by PCCT in the field of vascular imaging, while addressing promising future clinical scenarios
Spectral Photon-Counting Computed Tomography: Technical Principles and Applications in the Assessment of Cardiovascular Diseases
Spectral Photon-Counting Computed Tomography (SPCCT) represents a groundbreaking advancement in X-ray imaging technology. The core innovation of SPCCT lies in its photon-counting detectors, which can count the exact number of incoming x-ray photons and individually measure their energy. The first part of this review summarizes the key elements of SPCCT technology, such as energy binning, energy weighting, and material decomposition. Its energy-discriminating ability represents the key to the increase in the contrast between different tissues, the elimination of the electronic noise, and the correction of beam-hardening artifacts. Material decomposition provides valuable insights into specific elements’ composition, concentration, and distribution. The capability of SPCCT to operate in three or more energy regimes allows for the differentiation of several contrast agents, facilitating quantitative assessments of elements with specific energy thresholds within the diagnostic energy range. The second part of this review provides a brief overview of the applications of SPCCT in the assessment of various cardiovascular disease processes. SPCCT can support the study of myocardial blood perfusion and enable enhanced tissue characterization and the identification of contrast agents, in a manner that was previously unattainable
Plasmonic antenna hybrids for active control in the near and midinfrared
Resumen del trabajo presentado a la Spanish Conference on Nanophotonics (Conferencia Española de Nanofotónica-CEN), celebrada en Donostia-San Sebastián (España) del 3 al 5 de octubre de 2018.Hybrid platforms combining metallic plasmonic nanoantennas (NAs) and materials with interesting properties as phase-change or spintronics offer excellent technological opportunities for active plasmonics, as they can provide large changes in their optical response. In this talk I will demostrate first how gold NAs grown on vanadium dioxie
(VO2), characterized by a reversible insulator-to-metal transition (IMT) at around 68ºC, can improve the performance of this material by providing an efficient
enhancement mechanism for both the optically induced excitation and readout. Using picosecond laser pulses a highly localized phase transition is driven in nanoscale regions around the NAs. These antennas-VO2 hybrid solutions provide a conceptual framework to merge field localization and phase transition enabling nanoscale optical memory functionalities. In the second part I will show how the combination of Au microantenna arrays with a Ni81Fe19/Au multilayer supports provide metamaterial platforms with new functionalities. In this case, the plasmon resonance sustained by the NAs alliate with the GMR and MRE effects of the multilayer to allow low magnetic-field controlled modulation in the mid-infrared, where light modulation is very
challenging. This approach establishes a roadmap for spintronically-controlled
devices in the whole mid-IR to THz band.Peer Reviewe
Padrões fisiológicos hematológicos para Bugios-ruivos (Alouatta guariba clamitans): revisão de literatura: Physiological hematological patterns for howler monkeys (Alouatta guariba clamitans): literature review
As avaliações hematológicas são de suma importância na medicina veterinária, e, em animais ex situ, exames periódicos são necessários para monitorar a sanidade e bem-estar do plantel. Porém, para muitas espécies de animais silvestres, ainda é um desafio encontrar valores de referência padronizados para todos os componentes sanguíneos. Partindo deste princípio, o objetivo desta revisão é relatar os padrões fisiológicos hematológicos e bioquímicos para Bugios-ruivos (Alouatta guariba clamitans) hígidos descritos na literatura nacional e internacional. Os dados obtidos em diferentes estudos foram planilhados e discutidos na presente revisão. Considerando o grande número de animais pertencentes ao gênero Alouatta sp., conclui-se necessários novos estudos com aprofundamento da padronização de valores fisiológicos hematológicos, bioquímicos e hemostáticos, para obtenção de valores de referência de de animais hígidos da espécie Alouatta guariba clamitans, facilitando assim a distinção para o diagnóstico de patologias. Porém, ainda há poucos estudos conduzidos sobre a hematologia de primatas não-humanos de uma forma geral, levando em consideração as variáveis como idade, dieta, gênero, condições ambientais e estado reprodutivo, evitando assim a inferência de dados obtidos para outras espécies de primata-não-humanos do novo mundo
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