TiO2 Synthesis by Pechini Method and Application in Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSC) are devices to solar energy conversion, which present low production costs and high photoelectrochemical stability. The aim of this study was to investigate the synthesis of TiO2 by Pechini methodology, using C12H28O4Ti and TiCl3 as precursors, and their application in solar cell sensitized by N719 dye. The characterization techniques employed were Scanning Electron Microscopy (SEM), UV-VIS Spectroscopy, X-ray diffraction (XRD), photochronoamperometry, j-V Curves and EIS plots. The results demonstrated a high crystallinity and surface area to particles obtained with C12H28O4Ti as precursor. The highest photoconversion energy efficiency reached was to TiO2 using C12H28O4Ti with PCE= 4.17±0.13% with photoelectrochemical parameters of jsc= 5.53 ±0.08, Voc= 0.78±0.07 FF=0.58±0.05 and less resistive to charge transport with τe= 53 ms. DOI: http://dx.doi.org/10.17807/orbital.v13i2.144

Study of the Influence of Nb2O5 in ZnO Solar Cells

The solar cells of semiconductors oxides have been largely studied. The zinc oxide (ZnO) and niobium oxide (Nb2O5) used in this work presented important physical-chemical characteristics in use of photovoltaic devices. The Nb2O5 presents the capacity of minimizing effects of charge recombination in the process of energetic conversion of solar cells. The oxides used in this work were characterized by the technique X-ray diffraction. The solar cells containing 5% of Nb2O5 presented of best results in a relationship of the electron transfer process, reaching the efficiency of 0.42%. DOI: http://dx.doi.org/10.17807/orbital.v10i3.110

The corrosion of austenitic 304 stainless steel in biodiesel

As distribuidoras de combustíveis utilizam containers de aço inoxidável para o armazenamento de biocombustíveis, entretanto, na literatura, há poucos relatos sobre os aspectos corrosivos desse aço em biodiesel. O objetivo desse trabalho é estudar o comportamento corrosivo do aço inoxidável austenítico 304 na presença de biodiesel, não lavado e lavado com soluções aquosas de ácido cítrico, oxálico, acético e ascórbico 0,01 mol L-1e comparar com os resultados obtidos para o cobre (ASTM D130). Empregaram-se técnicas como: espectrometria de absorção atômica (EAA) e microscopia óptica (MO). Os resultados de EAA mostraram uma baixa taxa de corrosão para o aço inoxidável, os elementos de liga estudados foram Cr, Ni e Fe, a maior taxa observada foi para o cromo, 1,78 ppm/dia em biodiesel não lavado ou lavado. As MO do aço 304, quando comparados com as do cobre, comprovaram a baixa taxa de corrosão para o sistema aço 304/biodiesel, entretanto comprovaram que, tanto o aço 304, quanto o cobre, sofrem corrosão em amostras de biodiesel.Fuel distribution uses 304 stainless steel containers for the storage of biofuels, however, there are few reports in the literature about the corrosive aspects this steel in biodiesel. The objective of this research is to study the corrosive behavior of 304 austenitic stainless steel in the presence of biodiesel, unwashed and washed, with aqueous solutions of citric, oxalic, acetic and ascorbic acids 0,01 mol L-1, and compare with results obtained for the copper (ASTM D130). The employedtechniques were: atomic absorption spectrometry (AAS) and optical microscopy (OM). The results of EAA showed a low rate of corrosion for the stainless steel, the alloys elements studied were Cr, Ni and Fe, the highest rate was observed for the chrome, 1.78 ppm / day in biodiesel with or without washing. The OM of the 304 steel, when compared with that of copper, has a low corrosion rate in the 304 steel/biodiesel system. Not with standing, this demonstrates that not only the 304 steel, but also the copper, corrodes in biodiesel.CNP

Uso da Opinião Preliminar do INPI como Ferramenta de Gestão de Patentes em uma ICT Pública no Paraná

This research analyzes the impacts of using the Preliminary Opinion service of the National Institute of Industrial Property (INPI) in the patent deposit flow at the Federal University of Paraná (UFPR) between 2017 and 2022, as a portfolio management tool. This is a case study, with a quantitative approach, consisting of three stages of data collection in documentary sources provided by UFPR, and a stage of numerical analysis of collected data. The analysis showed that 56% of patent applications with rejection bias were abandoned, reducing portfolio swelling;  that BRL 84,000.88 were saved in INPI fees; and finally, that defenses filed based on the guidelines of Preliminary Opinion did not contribute to the granting of patents.. In view of the results, it is suggested to continue the activities with the restructuring of the filtering stages, and with the adoption of other patent writing tools.A presente pesquisa analisa os impactos da utilização do serviço de Opinião Preliminar do Instituto Nacional da Propriedade Industrial (INPI) no fluxo de depósito de patente da Universidade Federal do Paraná (UFPR) entre 2017 e 2022 como ferramenta de gestão de portfólio. Trata-se de um estudo de caso, com abordagem quantitativa, constituído por três etapas de coletas de dados em fontes documentais concedidas pela UFPR, e uma etapa de análise numérica dos dados coletados. A análise evidenciou que 56% dos pedidos de patente com viés de Indeferimento foram abandonados, reduzindo o inchaço do portfólio; que foram economizados R$ 84.000,88 em taxas do INPI; e, por fim, que as defesas peticionadas baseadas nas orientações da Opinião Preliminar não contribuíram para a concessão de patentes.  Diante dos resultados, sugere-se a continuidade das atividades com reestruturação das etapas de filtragem e com adoção de outras ferramentas de redação de patente

Enzymatic Hydrolysis of Cassava Starch Using Barley Malt Amylases

Barley malt was used as a source of amylases for the hydrolysis of cassava starch to produce reducing sugars for the alcoholic fermentation. Two routes of hydrolysis were evaluated in this work. One using milled barley malt and the other using the enzyme extract of this grain. The first one evaluated three concentrations of milled barley malt: 5, 10 and 15% (w/w) and there was no significant difference between the values of reducing sugars obtained as a function of the three concentrations. Three concentrations were also tested for barley malt extract: 0.5, 1.0 and 1.5 mL of extract. The higher content of reducing sugars was found for the 0.5 mL concentration of extract. The barley malt extract was more efficient in the enzymatic hydrolysis of cassava starch due to a better contact of the enzymes with substrate. The alcoholic fermentation of the wort obtained with 0.5 mL yielded an ethanol content of 7.74 ± 3.19 g/L with an efficiency of 88.6%. DOI: http://dx.doi.org/10.17807/orbital.v13i3.152

PRODUÇÃO DE HIDROGÊNIO A PARTIR DO ÁCIDO FÓRMICO UTILIZANDO ELETRODOS DE PLATINA, COBRE E LATÃO.

A preocupação mundial com a emissão de dióxido de carbono à atmosfera terrestre tem levado a exigências ambientais mais severas, e provocado o aumentado de estudos de geração de energias renováveis e menos poluentes, como por exemplo, o gás hidrogênio. Este trabalho tem como objetivo estudar a produção do gás hidrogênio via eletrólise da solução aquosa de ácido fórmico 3 mol L-1 , utilizando como eletrodos a platina, latão e cobre. As técnicas empregadas neste trabalho foram potencial de circuito aberto, polarização potenciodinâmica catódica e microscopia óptica. Os resultados obtidos mostram que os corpos de prova de latão lixados com lixas de SiC #320 apresentaram os maiores valores de densidade de corrente catódica, consequentemente maior produção de gás hidrogênio

Avaliação da corrosão do aço inoxidável 304 em meio de ácido sulfúrico e etanol

O principal co-produto obtido na síntese do biodiesel é a glicerina. Assim investiga-se um meio para converter a glicerina em produto de utilidade, como etanol combustível. Desta forma a decomposição da glicerina ocorre pela fermentação anaeróbica realizada com a bactéria Escherichia coli. O objetivo deste trabalho foi estudar o comportamento eletroquímico do aço inoxidável 304 em H2SO4 2 mol L-1, na ausência e presença de etanol em diferentes  concentrações. Foram empregadas como técnicas: medidas de potencial de circuito aberto, polarização potenciodinâmica anódica e catódica, espectroscopia de impedância eletroquímica, microscopia óptica e condutividade elétrica. A fermentação anaeróbica obteve um rendimento de 93,05 % etanol. Estudos de polarização anódica mostraram a existência de dois picos na região ativa, que de acordo com as micrografias ópticas são atribuídos a diferentes tamanhos de grãos, que ocorreram devido o tratamento térmico e associado a precipitação de caberto de cromo. Os diagramas de impedância eletroquímicos levantados mostram que o maior arco foi obtido para os sistemas contendo etanol. Nas curvas de polarização catódica averigou-se uma inibição do processo devido adsorção do etanol na superfície. A energia de adsorção foi de 2,05 104  cal k-1 mol-1, indica ser uma adsorção química

Application of Zinc Oxide Nanospheres for Hybrid Solar Cell

Poly(3-alkylthiophenes), P3AT, are organic polymers formed by conjugate structures with conductive properties. Zinc oxide (ZnO) has been used as an electron acceptor in hybrid solar cells because it offers electron transport properties and can be synthesized by methods in which the variation of synthesis parameters allows morphological control. Different ZnO morphologies allow for distinct properties in terms of electronic transport at the interface of solar cells. ZnO particles were synthesized by the co-precipitation method. ZnO films were deposited by spin-coating in Fluorine Tin Oxide (FTO) and then immersed in solutions containing poly (3-hexylthiophene) (P3HT) or poly (3-octylthiophene) (P3OT) polymers. The cell was assembled in the form of a sandwich consisting of: FTO/ZnO,P3AT/Iˉ,I3ˉ/Pt/FTO. UV-vis measurements were performed for bandgap calculation, scanning electron microscopy (SEM), X-ray diffraction (XRD), and J-V curves. The ZnO/P3HT cell presented the best values of J, V and η, indicating an improvement in the electronic transfer processes, with a value of η = 0.56%. DOI: http://dx.doi.org/10.17807/orbital.v13i2.145

Influence of Deposition Methodology and Heating Treatment on Dye Sensitized Solar Cell with Natural Extract

In this study, it was investigated the photovoltaic parameters of Dye Sensitized Solar Cells (DSSC) and the thin coating morphology of TiO2 by Doctor Blading and Spin Coating methods, sintered at 450 ºC and 450 ºC with a heating rate of 0.4 ºC s-1, using a natural dye extract from Hibiscus. These properties were studied by scanning electron microscopy (SEM), photochronoamperometry and curves j-V. It was demonstrated that all solar cells produced are photosensitive with an excellent charge injection. The cell with a better energy conversion (jsc = 0.53 mA cm-2; Voc= 0.471 V and FF= 0.518), uniform and flawless morphology was obtained to cell coated by Doctor Blading method, with a heat treatment of 450 ºC/0.4 ºC s-1. DOI: http://dx.doi.org/10.17807/orbital.v10i3.110

The influence of Annona muricata L. peel extract as a potent source of natural antioxidant on soybean oxidation stability: A influência do extrato de Annona muricata L. peel como uma potente fonte de antioxidante natural na estabilidade da oxidação da soja

Antioxidants are an alternative to prevent or retard biodiesel degradation. Soursop (Annona muricata L.) is a native tropical fruit with important antioxidant activity, besides high concentration of phenolic compounds. Peels form about 20 % of the soursop fruit composition and are usually discarded as a waste product. In this study the antioxidant potential of different peel extracts was evaluated by oxidative stability when used as an additive into soybean biodiesel. All samples were analyzed by the Rancimat® 873, using 32 experimental design. The tests were performed with biodiesel B100 with solutions extracted in different conditions, such as pH and residue concentrations. Results demonstrated that all experiments were able to increase significantly the induction period (IP), when compared to a pure biodiesel control sample, and showed similar efficiency with synthetic antioxidants (BHT). Among all experiments, each neutral and alkaline extractions presented induction periods over 8 h, achieving and surpassing the minimum allowed by European standard. However, the highest IP was found to be 10.30 h, with 3 g L-1 in neutral extraction.  Results corroborate that soursop peel has a high antioxidant capacity and efficiency to improve the oxidation stability, and could be used as an inexpensive natural antioxidant to biodiesel