Navegando por Assunto "Pigmentos"

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A arte com a natureza: experimentos de pigmentos naturais na educação do campo em alternância
(2018) Lima, Adriene Viana; Carvalho, Marluce Vasconcelos de; http://lattes.cnpq.br/2780914280180020; http://lattes.cnpq.br/6075580495835098
The present work aims to produce paints from the nature / field and use them in art classes. What led me to research on this subject was the desire to know more and more the field and the possibilities of transforming the natural materials into artistic, sustainable ones for the art classes, as well as to promote the artistic development of the students. The experiment was carried out with the students of the Agroecology course PROEJA (National Program for the Integration of Professional Education with Basic Education, in Youth and Adult Mode), which works in Alternance, in a rural school, in the municipality of Arataca-BA. For the development of such a study was contributed by the teaching of art in the context of Field Education and Alternation Pedagogy,proposing artistic practices from materials collected from nature. In the result of this research, I could observe that the students developed artistic activities, different from those that already had custom of doing. The experience of producing paints with students was well accepted by all, offering new learning in Art in dialogue with the pedagogy of Alternation.
Influência da adição da cal hidratada e pigmento em microconcretos coloridos
(2023-04-26) Floro, Jose Wellyngton Nunes; Galvão, Simone Perruci; http://lattes.cnpq.br/7867060015915634; http://lattes.cnpq.br/1523292800241605
The innovation in the construction industry regarding concrete performance and its architectural influence is noteble. Hence the importance of scientific studies based on new compositions. In this study, high-strength colored microconcretes were produced using two types of Portland cement, incorporating hydrated lime (CH I) into the mixture. A reference mix without pigment and without lime (dosed with Type V Portland cement - CP V and white structural Portland cement - CP B) was adopted, as well as other mixes, one for each type of cement, with pigment added and others with pigment and lime added. For the mixes dosed with pigment and lime, a pigment content of 5% and a lime content of 15%, both in relation to the cement mass, were added. The influence of both pigment and lime on compressive strength and coloration was verified at 28 days of age. The microconcrete consistency was analyzed through the flow table test (NBR 13276, 2002). The analysis showed that the microconcrete produced with CP B had more intense colors. Regarding axial compressive strength, the best performance was observed in pigmented concretes, with the best result obtained for the concrete with CP B cement and pigment, showing an increase of 31,67% compared to the standard microconcrete. Regarding consistency, a greater slump was observed in the concretes produced without lime in the mix.
Obtenção, caracterização e avaliação da estabilidade de pigmentos do extrato de beterraba (Beta vulgaris) microencapsulado por spray drying
(2019-07-03) Silva, Pedro Brivaldo Viana da; Ribeiro, Daniele Silva; http://lattes.cnpq.br/1517959077516490; http://lattes.cnpq.br/3523434440079567
The betalains are nitrogenous pigments, soluble in water, found abundantly in red beets and that present high antioxidant activity. Their use on a large scale is hampered due to the instability they present to various factors linked to food processing. Because of this, the microencapsulation technique can be employed to increase the stability of these compounds, in addition to facilitating handling during use. In this sense, the present work had the objective of extraction, characterizion and evaluation the stability of beet (Beta vulgaris) betalains, as well as microencapsulating the pigments through the spray drying process, using as carriers, maltodextrins of 15 and 20 DE. The extracts were obtained by means of an alcoholic extraction and caracterized, together with the raw material, in relation to moisture, pH, titratable acidity, ashes, reducing sugars, soluble solids and total betalains. A content of 44.96 and 38.75 mg/100 g of betalains was verified for the alcoholic extract and in natura beet, respectively. The betacyanins were evaluated for stability at temperatures of 50, 60, 70 and 80 ºC, verifying that they had a first order degradation kinetic reaction, from which, were calculated the kinetic parameters of the half-life, D-value, Z-value and activation energy, besides the thermodynamic parameters of enthalpy, Gibbs energy and entropy. The betacyanins were also evaluated for stability at pH, showing a more stable pH at 4 and 6. As for the powders obtained by the microencapsulation process, yields of 16.889 and 14.767% were verified for maltodextrins of 15 and 20 DE. Particles presented moisture (3.806 - 2.589%) and water activity (0.300 - 0.299) within those established to ensure good storage stability. They also presented low hygroscopicity (<15%) and high solubility (>90%). Microparticles produced with 20 DE maltodextrins showed improved results for apparent density (0.513g/mL), wettability (2.475 min) and less overall color difference after the drying process, in addition to indicating a betalains retention content of 87.2%, showing feasible characteristics for industrial applications.
Prospecção de pigmentos de fungos isolados de solo de área preservada
(2024-02-20) Souza, Ana Beatriz de Andrade; Siqueira, Virgínia Medeiros de; http://lattes.cnpq.br/5524459744893735; http://lattes.cnpq.br/2810164333813638
In recent years, several studies have highlighted the harmful effects of artificial substances used in the food, agriculture, and pharmaceutical industries, especially synthetic dyes. As an alternative to these substances, the search for fungi producing pigments has emerged as a promising option. Specifically, filamentous fungi have the ability to produce secondary metabolites that can replace synthetic products or serve as raw material for new products, minimizing this problem. In this context, the present study aimed to evaluate the pigment production capacity of filamentous fungi isolated from soil in a preserved area at the Curado Forest Wildlife Refuge (RVS), Recife-PE. After isolation and quantification procedures, five isolates capable of producing extracellular pigments in solid culture medium were selected, identified as Paecilomyces (isolates 01 and 11), Penicillium (isolate 07), Phoma (isolate 16), and Aspergillus (isolate 18). Subsequently, these fungi were cultured in liquid culture media and subjected to different pH, nutrient, and temperature conditions, with agitation at 150 rpm for 9 days. As a result, the conditions in which all isolates maintained pigment production were in Potato Dextrose Broth and Czpeck Broth, pHs 4.5 and 7.0, and temperature of 25°C, indicating that 15°C was a limiting factor when compared to all isolates tested. Additionally, the extract containing the pigments was tested for its antimicrobial capacity, but none of them showed activity against Candida albicans, Escherichia coli, and Staphylococcus aureus. Thus, it is concluded that soils from preserved areas are sources of fungi capable of producing extracellular pigments, which can be further studied in future research for their various applications. Finally, the results presented here emphasize the importance of maintaining preserved areas, valuing the fungal component present in soils, and that besides their ecological role, it is possible to add biotechnological value to them.
Síntese do pigmento CoCr2O4 pelo método de gelatina comercial
(2018) Sousa, Tassia Pereira de; Câmara, Maria Suely Costa da; http://lattes.cnpq.br/9163311260887432; http://lattes.cnpq.br/7879045291487919
There is a growing interest of the ceramic industries in developing more stable pigments that are low cost and little environmental damage. The ceramic industries mainly use pigments of predominantly inorganic nature, such pigments are the most used because they havean excellent chemical and thermal stability besides a lower toxicity to the man and few environmental damages. The most commonly used inorganic pigments used in ceramics are mixed oxides with spinel structure and AB2O4. Spinels are one of the most interesting crystalline structures in the development of stable and chemically inert pigments. In this structure, ions of different oxidation states are present in both tetrahedral and octahedral sites. In addition, there are several ways of arranging the cationsat these sites (normal and inverse spinel). These characteristics led to the development of different colors, being these intense and stable, suitable for use as pigments. Among the compounds used as ceramic pigments, we have highlighted CoCr2O4which is a mineral oxide belonging to the group of spinel, such structures cover a group of well-establishedmagnetic materials that may have a green coloration. The objective of the present work was to synthesize the CoCr2O4pigment using commercial gelatin as precursor and to characterize the following techniques: Thermogravimetric analysis (TG), Xray diffraction (XRD), surface area (BET), Scanning electron microscopy (SEM) spectroscopy in the infrared region (FTIR), and colorimetric measurements by the CIEL*a*b*method. The route of synthesis used was confirmed viable from the results. Crystalline, monophasic and high surface area compounds were obtained. The powders presented green coloration with phase obtained from 500 ºC.