291 research outputs found
Scientific specialties in Green Chemistry
Objective. This paper presents an overview of Green Chemistry research from 1990 to 2017, identifying its specialties, comparing their relative importance, and inferring emergent trends.
Design/Methodology/Approach. Co-citation analysis of 14,142 documents retrieved in Web of Science by CiteSpace software, using network analysis to describe research fronts by clustering, their relevance by clusters indicators, and emergence by citation burstiness.
Results/Discussion. Sixteen clusters were found and then grouped into six big specialties. Some specialties are more persistent and general (e.g. GC Characterization, Metal Catalysis, and Microwave Activation) and others are more recent and focused (e.g. Deep Eutectic Solvents). Mechanochemical and Photochemistry are emergent trends in Green Chemistry.
Conclusions. This paper presents a more quantitative/objective panorama of GC research, comparing the relevance of research fronts inside the field, and helping future researchers and decision-makers in further developments of GC. CiteSpace showed some limitations in clustering. Data collection was hurdled by changes in the Keyword Plus algorithm in Web of Science and by the lack of authors keywords in main journals of the field. Although large, the dataset was restricted to the Web of Science database.
Originality/Value. To the best of our knowledge, this is the first quantitative analysis of research specialties of GC. It advances past peer evaluation of the field by using indicators and metrics to describe the emergence, extension, and decay of specialties
An AI-based object detection approach for robotic competitions
Artificial Intelligence has been introduced in many
applications, namely in artificial vision-based systems with object
detection tasks. This paper presents an object localization system
with a motivation to use it in autonomous mobile robots at
robotics competitions. The system aims to allow robots to accomplish
their tasks more efficiently. Object detection is performed
using a camera and artificial intelligence based on the YOLOv4
Tiny detection model. An algorithm was developed that uses the
data from the system to estimate the parameters of location,
distance, and orientation based on the pinhole camera model and
trigonometric modelling. It can be used in smart identification
procedures of objects. Practical tests and results are presented,
constantly locating the objects and with errors between 0.16 and
3.8 cm, concluding that the object localization system is adequate
for autonomous mobile robots.The authors are grateful to the Foundation for Science
and Technology (FCT, Portugal) for financial support
through national funds FCT/MCTES (PIDDAC) to CeDRI
(UIDB/05757/2020 and UIDP/05757/2020). The project that
gave rise to these results received the support of a fellowship
from ”la Caixa” Foundation (ID 100010434). The fellowship
code is LCF/BQ/DI20/11780028. João Braun is a PhD Student
at the Faculty of Engineering, University of Porto (FEUP)
supervised by Prof. Paulo Costa.info:eu-repo/semantics/publishedVersio
Gum of Terminalia argentea Mart. Et. Zucc. (Combretaceae) as a Resource in Biotechnology Processes: Chemistry and Toxicity
Biodegradable polymers are in areas such as pharmaceutical, food and bioremediation processes. Isolation, characterization (SEM, FTIR, TGA, Monosaccharide Composition, Zeta Potential), antimicrobial activity and toxicity to Artemia salina and Allium cepa L. from the in natura gummy exudate of Terminalia argentea (GTa) are presented herein. The data show irregular morphology and depressions, bands in 1770, 2112, 1354 cm-1, indicating groups of polysaccharides, amphiphilic character, thermo-degradation above 300 ° C and low water activity (0.6). The assays were negative for S. aureus and E. coli, nontoxic against the bioindicators tested. GTa presented low cost, extracted and isolated in a sustainable way, with possibility of commercial exploitation by communities, since these biopolymers present possibilities of applications as agents in the support of immobilization of enzymes, as sensors in diagnostics, encapsulating material in processes of microencapsulation of drugs and additives in food industries.Polímeros biodegradáveis estão em áreas como a farmacêutica, alimentos e processos de bioremediação. O isolamento, a caracterização (MEV, FTIR, TGA, Composição de monossacarídeos, Potencial Zeta), atividade antimicrobiana e toxicidade frente a Artemia salina e Allium cepa L. do exsudato gomoso in natura de Terminalia argentea (GTa) são aqui apresentados. Os dados mostram morfologia irregular e depressões, bandas em 1770, 2112, 1354 cm-1, indicando grupamentos de polissacarídeos, caráter anfiflitico, termodegradação acima de 300°C e baixa atividade de água (0.6). Os ensaios foram negativos para S. aureus e E. coli, atóxicos frente aos bioindicadores testados. O GTa apresentou-se de baixo custo, extraído e isolado de forma sustentável, com possibilidade de exploração comercial por comunidades, uma vez que estes biopolímeros apresentam possibilidades de aplicações como agentes no suporte de imobilização de enzimas, como sensores em diagnósticos, material encapsulante em processos de microencapsulação de fármacos e aditivos em indústrias de alimentos
Uso de tecnologia fotovoltaica em fachadas prediais com vidro refletivo: um estudo de alternativa de retrofit
Development of a Behavioral Performance Measure
Since the fifties, several measures have been developed in order to measure the performance of investments or choices involving uncertain outcomes. Much of these measures are based on Expected Utility Theory, but since the nineties a number of measures have been proposed based on Non-Expected Utility Theory. Among the Theories of Non-Expected Utility highlights Prospect Theory, which is the foundation of Behavioral Finance. Based on this theory this study proposes a new performance measure in which are embedded loss aversion along with the likelihood of distortions in the choice of alternatives. A hypothetical example is presented in which various performance measures, including the new measure are compared. The results showed that the ordering of the assets varied depending on the performance measure adopted. According to what was expected, the new performance measure clearly has captured the distortion of probabilities and loss aversion of the decision maker, ie, those assets with the greatest negative deviations from the target were those who had the worst performance
FLEXIBILITY AND UNCERTAINTY IN AGRIBUSINESS PROJECTS: INVESTING IN A COGENERATION PLANT
Concerns about global warming and high oil prices have spearheaded the search for alternate and more environmentally friendly sources of energy. One of the developments that has shown exceptional value is the increasing use of ethanol derived from biomass such as sugarcane, corn, beet and wheat. As the world's largest producer of sugar cane, Brazil has benefited from this trend to become also the largest producer of ethanol after the United States. Energy generation from biomass has also become a source of increasing interest due to growing environmental concerns and the depletion of the world's fossil fuel reserves. In this paper we analyze a sugar and ethanol producing sugar cane mill in Brazil that has both the option to expand production and invest in a more efficient bioelectricity cogeneration unit to allow the generation and sale of surplus bioelectricity generated from sugarcane bagasse, where the second option is conditional on the first one being exercised. The option to expand production is a function of the expected future prices of sugar and ethanol, while the decision to invest in the cogeneration plant will depend on future prices of energy. Both decisions are modeled as American type compound options over their respective underlying uncertainties. Many authors such as Schatzki
A relação entre o verbal e o visual em placas, anúncios publicitários e ilustrações
Diante da imensa diversidade de composições de caráter visual com que nos envolvemos diariamente, torna-se essencial refletir criticamente sobre os processos de linguagem por meio dos quais uma imagem produz sentidos, em especial em relação ao texto verbal que a acompanha. Tendo esse objetivo e atentando para a relação de composição que caracteriza as associações entre materialidades significantes, este trabalho apresenta a análise de três tipos de objetos simbólicos materialmente heterogêneos: placas de trânsito, anúncios publicitários e ilustrações de livros. Desenvolvido ao longo da produção de um material didático envolvendo os conceitos de interdiscurso, efeito metafórico e efeito metonímico, o estudo aponta para sua grande aplicabilidade na compreensão do funcionamento desse tipo de composição, cujo sentido só se dá efetivamente na relação entre as materialidades significantes envolvidas
Exercício de intensidade moderada durante a gravidez é seguro para o feto? Ensaio clínico aberto
To determine the effect of treadmill walking on maternal heart rate (MHR) and cardiotocographic parameters (basal fetal heart rate [FHR], active fetal movements [AFM], number of accelerations and decelerations, and short-term variation [STV] and long-term variation [LTV] of fetal heart rate) in pregnant women at 36 weeks. Methods A nonrandomized, open clinical trial involving 88 healthy pregnant women submitted to moderate intensity walking and computed cardiotocography in 3 20-minute periods (resting, treadmill walking, and postexercise recovery). Results The mean FHR decreased during walking (resting: 137 bpm; treadmill: 98 bpm; recovery: 140 bpm; p <0.001), with bradycardia occurring in 56% of the fetuses in the first 10minutes of exercise, and in 47% after 20minutes. Bradycardia was not detected in the other phases. The mean STV and HV were 7.9, 17.0, and 8.0 milliseconds ( p <0.001) and 7.6, 10.8 and 7.6 bpm ( p =0.002) in the resting, walking and recovery phases, respectively. The mean number of fetal movements in 1 hour was 29.9, 22.2 and 45.5, respectively, in the 3 periods ( p <0.001). In overweight/obese women, the mean FHR was lower ( p =0.02). Following the logistic regression analysis, two variables remained significantly associated with bradycardia: maternal fitness in the 28 (th) week of pregnancy (protective effect) and maternal weight (increased risk). Conclusion In healthy fetuses, physical exercise proved to be safe, since, although FHR and AFM decreased during treadmill walking, an increase in SVT and LTV was observed419531538CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DA PARAÍBA - FAPESQUniversal 480761/2008-6PPSUS2009Determinar o efeito da caminhada em esteira sobre a frequencia cardiaca materna (FCM) e parametros cardiotocograficos (batimentos cardiofetais basais [BCFs], movimentos ativos fetais [MAFs], numero de aceleracoes e desaceleracoes e variabilidade de curta [STV] e longa [LTV] duracAo da frequencia cardiaca fetal) em gestantes na 36 (a) semana. Metodos Foi realizado um ensaio clinico nAo randomizado e aberto com 88 gestantes saudaveis submetidas a caminhada de moderada intensidade na esteira e a cardiotocografia computadoriza em 3 momentos de 20 minutos (antes, durante e apos a caminhada). Resultados A media dos BCFs diminuiu durante a caminhada, retornando a niveis previos (antes: 137 bpm; durante: 98 bpm; apos: 140 bpm; p <0,001), com bradicardia ocorrendo em 56% dos fetos nos primeiros 10 minutos do exercicio, e em 47% apos 20 minutos. A bradicardia fetal nAo foi observada em outros momentos (antes ou depois). As medias da STV e da LTV foram 7,9, 17,0 e 8,0 milissegundos ( p <0,001) e 7,6, 10,7 e 7,6 bpm ( p =0,002) antes, durante e apos a caminhada, respectivamente. A media dos numeros dos MAFs em 1 hora foi 29,9, 22,2 e 45,5, respectivamente, nos tres momentos ( p <0,001). Nas mulheres com sobrepeso/obesidade, a media da FCM foi menor ( p =0,02). Apos a analise de regressAo logistica, duas variaveis permaneceram significativamente associadas a bradicardia: aptidAo maternal na 28 (a) semana de gravidez (efeito protetor) e peso materno (aumento do risco). ConclusAo Em fetos saudaveis, o exercicio fisico mostrou-se seguro, uma vez que, embora os BCFs e os MAFs diminuam durante a caminhada na esteira, foi observado um aumento da SVT e da LT
Distribuição de Lutzomyia whitmani em fitorregiões do estado do Maranhão, Brasil
The study had the aim of characterizing the geographical distribution of Lutzomyia whitmani s.l. in the state of Maranhão, Northeastern Brazil. Between 1992 and 2005, 9,600 specimens (65.1% males and 34.9% females) were caught in the rural and urban zones of 35 municipalities in regions consisting of forests, savanna and mixed vegetation with coconut plantations, sandbanks and heath. Greater abundance was observed in areas surrounding dwellings (91.6%) than inside the dwellings (8.4%). The presence of the vector in different phytoregions and in rural and urban areas favors the transmission of tegumentary leishmaniasis in these environments. This taxon may constitute a complex of species in Maranhão, which can be confirmed by molecular biology studies.El estudio tuvo por objetivo caracterizar la distribución geográfica de Lutzomyia whitmani s.l. en el estado de Maranhão, en Norte de Brasil. De 1992 a 2005, fueron capturados 9.600 especimenes (machos: 65,1% y hembras: 34,9%) en las zonas rurales y urbanas de 35 municipios situados en áreas de bosque, sabana y vegetación mixta con cocal, restinga y caatinga. La abundancia fue mayor en el peri domicilio (91,6%) con respecto al intra domicilio (8,4%). La presencia del vector en diferentes fitoregiones y en las áreas rurales y urbanas favorece la transmisión de la leishmaniasis tegumentar en esos ambientes. Es posible que ese taxón constituya un complejo de especies en el Maranhão, lo que podrá ser confirmado mediante estudios de biología molecular.O estudo teve por objetivo caracterizar a distribuição geográfica de Lutzomyia whitmani s.l. no estado do Maranhão. De 1992 a 2005, foram capturados 9.600 espécimes (machos: 65,1% e fêmeas: 34,9%) nas zonas rurais e urbanas de 35 municípios situados em áreas de floresta, cerrado e vegetação mista com cocal, restinga e caatinga. A abundância foi maior no peridomicílio (91,6%) do que no intradomicílio (8,4%). A ocorrência do vetor em diferentes fitorregiões e nas áreas rurais e urbanas favorece a transmissão da leishmaniose tegumentar nesses ambientes. É possível que esse táxon constitua um complexo de espécies no Maranhão, o que poderá ser confirmado mediante estudos de biologia molecular
Utilização de tomografia de pulso eco ultrassônica para identificação de manifestações patológicas no interior de pilares de concreto armado
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