897 research outputs found

    Design and Fabrication of Flexible Copper Sensor Decorated with Bismuth Micro/Nanodentrites to Detect Lead and Cadmium in Noninvasive Samples of Sweat

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    The use of economic methods to design and fabricate flexible copper sensors decorated with bismuth micro/nanodentrites for the detection of lead and cadmium in sweat is demonstrated. The flexible copper sensors were constructed with simple and cost-effective materials; namely, flexible and adhesive conductive copper tape, adhesive label containing the design of a three-electrode electrochemical system, and nail polish or spray as a protective layer. The flexible copper device consisted of a working electrode decorated with bismuth micro/nanodentrites using an electrodeposition technique, a copper pseudo-reference and copper counter electrodes. Under optimal experimental conditions, the flexible sensing platform showed excellent performance toward the detection of lead and cadmium using differential pulse anodic stripping voltammetry (DPAdSV) in a wide linear range from 2.0 μM to 50 μM with acceptable reproducibility and repeatability, and limits of detection and quantification of 5.36 and 17.9 μM for Cd2+ ions and 0.76 μM and 2.5 for Pb2+ ions. Studies of addition and recovery in spiked artificial sweat sample were performed, with a recovery of 104.6%. The flexible copper device provides a great opportunity for application in wearable perspiration-based healthcare systems or portable sensors to detect toxic metals in biological samples

    Overcoming inertia : drivers of the outsourcing process

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    Almost all managers have directly or indirectly been involved in the practice of outsourcing in recent years. But as they know, outsourcing is not straightforward. Outsourcing inertia, when companies are slow to adapt to changing circumstances that accommodate higher outsourcing levels, may undermine a firm’s performance. This article investigates the presence of outsourcing inertia and the factors that help managers overcome it. Using statistical evidence, we show that positive performance effects related to outsourcing can accumulate when circumstances change. This is then followed by rapid increases in outsourcing levels (i.e. outsourcing processes). We investigate what gives rise to these outsourcing processes through follow-up interviews with sourcing executives, which suggest five drivers behind outsourcing processes: managerial initiative (using outside experience); hierarchy (foreign headquarters); imitation (of competitors and of similar firms); outsider advice (from external institutions); knowledge sources (using external information). These five drivers all offer scope for managerial action. We tie them to academic literatures and suggest ways of investigating their presence and impact on the outsourcing process. Overall, we conclude that while economizing factors play a key role in explaining how much firms outsource, it is socializing factors that tend to drive outsourcing processes

    Development of the 'MN''SI IND. 1.7' phase in 'MN'-containing 'SI' films

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    Thin films of Si with Mn concentrations up to 20 at.% were prepared by conventional radio frequency sputtering. After deposition, the films were submitted to thermal annealing treatments and their properties were investigated by composition analysis, Raman scattering, microscopic techniques, optical transmission, and electrical transport. The experimental results show that all as-deposited films are amorphous, with the Mn atoms being effective and controllably incorporated into the Si matrix. Moreover, thermal annealing at increasing temperatures induces the crystallization of the films as well as the growth of the MnSi1.7 silicide phase in the Mn-containing samples. Along with sample crystallization, some films become covered by small structures that are randomly distributed all over their surfaces. These structures are essentially Mn-containing Si crystals with typical sizes in the (sub-) micrometer range and, as the thermal annealing advances, the density of structures increases at the expense of their individual average dimension. The development and characteristics of the observed superficial structures are discussed in view of the main structural and morphological properties of the samples.FAPESPCNP

    Electrochemical Behavior of Cellulose Nanofibrils Functionalized with Dicyanovinyl Groups

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    Cellulose is considered one of the most important renewable sources of biopolymers on Earth. It has attracted widespread attention due to its physical–chemical characteristics, such as biocompatibility, low toxicity, biodegradability, low density, high strength, stability in organic solvents, in addition to having hydroxyl groups, which enable its chemical modification. In this study, cellulose nanofibrils (CNFs) were functionalized with dicyanovinyl groups through nucleophilic vinylic substitution (SNV) and used as electrocatalyst in electrochemical of carbon dioxide (CO2) reduction. Results indicate that introducing dicyanovinyl groups into the structure of nanocellulose increases electrocatalytic activity as compared to that of pure nanocellulose, shifting the onset potential of the electrochemical CO2 reduction reaction to more positive values as compared to those for the reaction with argon. The atomic force microscopy (AFM) images show no changes in the morphology of CNFs after chemical modification

    Os conselhos de meio ambiente e desenvolvimento da região da APA de Guaraqueçaba: relações, sobreposições e perspectivas futuras

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    O trabalho que segue busca analisar os resultados do levantamento de conselhos existentes na região da Área de Proteção Ambiental (APA) de Guaraqueçaba. Tal levantamento foi realizado no formato de um diagnóstico das competências e atribuições de conselhos de “meio ambiente” e de "desenvolvimento” atuantes nos municípios onde se insere a APA Federal de Guaraqueçaba, litoral norte do Paraná. Foram realizadas 16 entrevistas com gestores ou secretários executivos dos conselhos e acessados 22 documentos legais para tradução de temas/competências gerais desses espaços. Observou-se 21 temas gerais, divididos em três campos: Articulação, Planejamento e Intervenção. Visualizando os vários temas que os conselhos trabalham e as diversas sobreposições entre estes, nota-se que formas de interação e de diálogo são necessárias para otimizar o trabalho de todos. Apresentando esses resultados para diferentes atores sociais, inclusive os gestores destes espaços públicos, percebeu-se, apesar dessa potencialidade, que as dificuldades financeiras e logísticas em realizar reuniões de conselhos; as diferentes concepções institucionais acerca do que seja um conselho atuante; e as constantes trocas de gestores municipais são exemplos de fatores que desestimulam as oportunidades das diferentes políticas públicas serem pensadas e geridas de forma articulada e cooperada no território. Discute-se, com esse trabalho, que com a existência de diversas políticas públicas incidentes em um mesmo território, a convergência e a possibilidade de integração entre elas estão sujeitas a uma maior ou menor capacidade dos gestores destas políticas perceberem e fomentarem estes processos, das estruturas político-administrativas de seus órgãos respectivos estarem dispostas a esta convergência, em todos os níveis governamentais, bem como, também, pela própria sociedade provocar e atuar nesta nova perspectiva. Portanto, a partir deste entendimento, cabe aos diferentes gestores, com a possibilidade de trabalho em parceria, e a cada membro da sociedade, conjuntamente, criar meios e oportunidades para que as políticas públicas tornem-se, no máximo possível, verdadeiros instrumentos de transformação de realidades. Isso considerando sempre a busca do aperfeiçoamento de seus instrumentos de participação social, em prol de um desenvolvimento que considere seus diferentes componentes: ambiental, social, político, cultural, econômico e espacial

    Reduced graphene oxide multilayers for gas and liquid phases chemical sensing

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    Graphene oxide (GO) multilayers were produced by the layer-by-layer technique after successive immersions of quartz slides into aqueous suspensions of cationic poly(diallyldimethyl ammonium chloride) (PDAC) and anionic GO. The adsorbed amount of GO within the multilayers measured ex situ by UV-vis spectroscopy was found to increase linearly with the number of PDAC-GO bilayers. UV-vis and Raman spectra confirmed the conversion of GO to its reduced form, namely reduced graphene oxide (RGO), when the multilayers were subjected to hot hydrazine. According to AFM images, multilayers are flat with GO sheets forming edge structures. Additionally, impedance spectroscopy provided information regarding the multilayer growth mechanism, which starts with isolated GO sheets that bridge each other after deposition of five PDAC-GO bilayers. As a proof of principle, it was demonstrated that a sensor array composed by reduced multilayers deposited onto interdigitated microelectrodes and interrogated by impedance spectroscopy is capable of discriminating vapours of volatile solvents, including toluene, gasoline, ethanol, chloroform, and acetone, as well as chemicals in aqueous solutions, such as hydrochloric acid, sodium chloride, ammonium hydroxide, and sucrose. This capability was made possible only because the LbL assembly permitted one to tune the sensors' sensitivity with the number of PDAC-GO bilayers. The results presented herein suggest that the reduced PDAC-GO multilayers are promising elements for non-specific chemical sensors.CNPq (308038/2012-6)CAPE

    Caracterização molecular do Cão Barbado da Terceira

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    Dissertação de Mestrado em Engenharia Zootécnica.Neste trabalho analisaram-se 257 animais da raça Cão Barbado da Terceira sendo caracterizados geneticamente, por doze microssatélites identificando-se um total de 79 alelos. A variabilidade genética foi estimada através das frequências alélicas, diversidade genética, heterozigocidade esperada e observada, probabilidade de identidade e verificação do equilíbrio de Hardy-Weinberg. Analisou-se as distâncias genéticas entre grupos pré-definidos consoante o ano de nascimento. Realizaram-se testes de paternidade comparando com os dados cedidos pelos criadores dos animais em questão, com bons resultados confirmando-se a compatibilidade com os progenitores na maioria dos casos. A população continua a manter variabilidade genética suficiente para não sofrer um processo de inbreeding, contudo deve ser dada atenção aos reprodutores a serem utilizados no futuro de forma a se conseguir uma maior heterozigocidade na raça para que haja uma evolução positiva da mesma. Desta forma os objectivos deste trabalho foram conseguidos, sendo este tipo de marcadores moleculares suficientemente informativos para esta caracterização.ABSTRACT: In this study 257 animals from the Cão Barbado da Terceira breed were analyzed, which were genetically characterized with twelve microsatellites, with a total of 79 alleles identified. The genetic variability was estimated through the allelic frequencies, genetic diversity, expected and observed heterozygosity, identity probability and verification of the Hardy-Weinberg equilibrium. There was also the analysis of the genetic distances between groups predefined according to the year of birth, as well as paternity tests by the comparison with the data provided by the breeders. Good results were obtained and the compatibility with the parents was confirmed in most cases. The population still maintains enough genetic variability in order not to undergo inbreeding however one should pay attention to the breeders to be used in the future, in a way to obtain a higher heterozygosity so there is a positive evolution of the breed. Therefore the aims of this study were achieved, and this type of molecular markers was sufficiently informative for this characterization

    Investigation in SrTi'O IND.3'-CaTi'O IND.3'-PbTi'O IND.3' ternary thin films by dielectric proprieties and Raman spectroscopy

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    Dielectric and Raman scattering experiments were performed on polycrystalline Pb1−x−yCaxSryTiO3 thin films as a function of temperature. Temperature-dependent dielectric measurements revealed a decreasing ferroelectric-to-paraelectric phase transition temperature and peak dielectric permittivity showed a broad phase transition near room temperature with increasing levels of CaO12 and SrO12 clusters. Therefore, for higher levels of substitution, the possible random position of the CaO12 and SrO12 clusters leads to a diffuse state. At 100 kHz, the ferroelectric-to-paraelectric phase transition temperatures were 633, 495 and 206 K for PCST90 (Pb0.90Ca0.05Sr0.05TiO3), PCST70 (Pb0.70Ca0.15Sr0.15TiO3) and PCST30 (Pb0.30Ca0.35Sr0.35TiO3) thin films, respectively. The evolution of the Raman spectra was also studied as a function of temperature. The temperature dependence of the E(1TO) soft mode frequencies was used to characterize the phase transition. Raman peaks were observed above the ferroelectric-to-paraelectric phase transition temperature, although all optical modes should be inactive in Raman scattering. The origin of these modes was interpreted as a breakdown of the local cubic symmetry by the random distribution of CaO12 and SrO12 clusters.CNPqCAPESFAPESP/CEPID (06/53926-4)FAPESP/CEPID (08/53515-7)FAPESP/CEPID (06/51640-6
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