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New compounds, chemical composition, antifungal activity and cytotoxicity of the essential oil from Myrtus nivellei Batt. & Trab., an endemic species of Central Sahara

Bouzabata, Amel; Bazzali, Ophélie; Cabral, Célia; Gonçalves, Maria José; Cruz, Maria Teresa; Bighelli, Ange; Cavaleiro, Carlos; Casanova, Joseph; Salgueiro, Ligia; Tomi, Félix
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
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Ethnopharmacologic relevance Myrtus nivellei Batt. & Trab. (Myrtaceae) known as Sahara myrtle is appreciated by the Touaregs as medicinal plant. Infusion of leaves is employed against diarrhea and blennorrhea. Crushed leaves added to oil or to butter ointment have been traditionally used for the treatment of dermatosis. Aim of the study is to consider the traditional medicinal uses and the lack of scientific studies on their biological activities, the present study was designed to elucidate the chemical composition, the antifungal activity of its essential oils against fungi responsible for human infections, as well as, its cytotoxicity in the mammalian keratinocytes. Materials and methods Chemical analysis of Myrtus nivellei essential oil isolated by hydrodistillation of aerial parts (leaves and flowers), was carried out using a combination of chromatographic (CC, GC with retention indices) and spectroscopic techniques (MS, 13C NMR, 2D NMR). The antifungal activity was evaluated by using broth macrodilution methods for yeasts and filamentous fungi. Cytotoxicity was tested in HaCaT keratinocytes through the MTT assay. Results Ten samples coming from two localities of harvest were investigated. The chemical composition was largely dominated by 1...

Chemical composition changes in eucalyptus and pinus woods submitted to heat treatment

BRITO, J. O.; SILVA, F. G.; LEAO, M. M.; ALMEIDA, G.
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
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66.06%
This study investigated the influence of heat treatment on the chemical composition of Eucalyptus saligna and Pinus caribaea var. hondurensis woods to understand its role in wood processing. E. saligna and P. caribaea var. hondurensis woods were treated in a laboratorial electric furnace at 120, 140, 160 and 180 degrees C to induce their heat treatment. The chemical composition of the resulting products and those from original wood were determined by gas chromatography. Eucalyptus and Pinus showed a significant reduction in arabinose, manose, galactose and xylose contents when submitted to increasing temperatures. No significant alteration in glucose content was observed. Lignin content, however, increased during the heat process. There was a significant reduction in extractive content for Eucalyptus. On the other hand, a slight increase in extractive content has been determined for the Pinus wood. and that only for the highest temperature. These different behaviors can be explained by differences in chemical constituents between softwoods and hardwoods. The results obtained in this study provide important information for future research and utilization of thermally modified wood. (c) 2008 Elsevier Ltd. All rights reserved.; State of Sao Paulo Research Foundation (FAPESP).

CHEMICAL COMPOSITION OF SUGAR CANE SPIRITS FERMENTED BY DIFFERENT Saccharomyces cerevisiae YEAST STRAINS

Alcarde, André Ricardo; Monteiro, Bruno Miguel dos Santos; Belluco, André Eduardo de Souza
Fonte: SOC BRASILEIRA QUIMICA; SAO PAULO Publicador: SOC BRASILEIRA QUIMICA; SAO PAULO
Tipo: Artigo de Revista Científica
POR
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66.06%
CHEMICAL COMPOSITION OF SUGAR CANE SPIRITS FERMENTED BY DIFFERENT Saccharomyces cerevisiae YEAST STRAINS. The aim of this study was to evaluate the chemical composition of sugar cane spirits, fermented by different commercial Saccharomyces cerevisiae yeast strains and double distilled by pot still. Sugar cane juices were separately fermented by yeasts CA-11, Y-904, BG-1, PE-2, SA-1 and CAT-1 and distilled by pot still according to the methodology used for whisky production. The alcoholic liquids from first and second distillations were analyzed for concentrations of ethanol, volatile acidity, aldehydes, esters, furfural, higher alcohols and methanol. The sugar cane spirits derived from fermentation by the different yeast strains presented distinct chemical compositions.

Quantificação das vitaminas antioxidantes E (α-, β-, γ-, δ-tocoferol), C (ácido ascórbico), pró-vitamina A (α-, β-Caroteno) e composição química do pólen apícola desidratado produzido em apiários georreferenciados da região Sul do Brasil; Quantification of antioxidant vitamins E (α-, β-, γ-, δ-tocopherol), C (ascorbic acid), provitamin A (α-, β-carotene) and chemical composition of dehydrated bee pollen produced in georeferenced apiaries of southern Brazil.

Sattler, José Augusto Gasparotto
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/01/2014 PT
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O objetivo geral deste trabalho foi quantificar as vitaminas antioxidantes (tocoferóis, ácido ascórbico, α- e β-caroteno) bem como a composição química de amostras de pólen apícola obtidas em apiários georreferenciados da região sul do Brasil e desidratadas de forma controlada conforme recomendação da legislação brasileira. Inicialmente foi realizada a composição química de 21 amostras de pólen apícola desidratados sendo os valores médios de 3,37% para umidade, 19,80% para proteínas, 3,44% para lipídios, 2,02% para cinzas. Pode-se verificar que a maioria das amostras encontraram-se dentro dos parâmetros de qualidade preconizados pela legislação brasileira. Além disso, utilizando a cromatografia líquida de alta eficiência (CLAE), foi confirmando a presença de açúcares redutores glicose (6,77%) e frutose (5,39%) nas amostras. A determinação da vitamina C foi realizada por titulometria e os valores encontrados variaram entre 60 e 797 µg/g, sendo duas amostras consideradas fonte desta vitamina para homens e três para mulheres conforme a Ingestão Dietética de Referência (IDR). Já os tocoferóis e o α- e β-caroteno foram analisados por CLAE. Com relação aos tocoferóis (α-...

Chemical composition of Rhodocyclus gelatinosus biomass produced in poultry slaughterhouse wastewater

Ponsano, Elisa Helena Giglio; Lacava, Pedro Magalhães; Pinto, Marcos Franke
Fonte: Brazilian Archives of Biology and Technology Publicador: Brazilian Archives of Biology and Technology
Tipo: Artigo de Revista Científica Formato: 143-147
ENG
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66.09%
Rhodocyclus gelatinosus R1 foi cultivado fotoautotroficamente em águas residuais de abatedouro de aves dentro de colunas de vidro (90x670 mm) durante sete dias a 31 ± 4ºC, sob anaerobiose e intensidade luminosa fornecida pela luz do dia e por três lâmpadas incandescentes (100W) mais quatro lâmpadas fluorescentes (40W). O cultivo obtido foi centrifugado (4.500xg/20 min) e liofilizado, originando a biomassa bacteriana, que continha 7,1% de umidade. A determinação da composição centesimal indicou (base seca) 67,6% de proteína bruta, 27,6% de carboidratos totais, 0,6% de lipídeos e 4,2% de cinzas. A composição em aminoácidos da fração protéica da biomassa mostrou-se semelhante à relatada na literatura para Rhodocyclus gelatinosus e para outras bactérias fotossintetizantes. A redução na DQO do efluente após o cultivo e a retirada da biomassa foi da ordem de 90%. A valiosa composição química da biomassa de Rhodocyclus gelatinosus R1 e o alto conteúdo em aminoácidos essenciais indicam o uso potencial desse produto na suplementação de ração para aves.; Rhodocyclus gelatinosus R1 grew photoautotrophically in poultry slaughterhouse wastewater inside glass columns (90x670 mm) during 7 days at 31 ± 4ºC...

Antimicrobial Activity and Chemical Composition of the Essential Oils of Portuguese Foeniculum vulgare Fruits

Mota, Ana; Martins, M. Rosário; Arantes, Silvia; Lopes, Violeta; Bettencourt, Eliseu; Pombal, Sofia; Gomes, Arlindo; Silva, Lúcia
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
ENG
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The aim of this study was to investigate the chemical composition and antimicrobial activity of essential oils obtained by hydrodistillation from fruits of six fennel accessions collected from wild populations occurring in the centre and south of Portugal. Composition of essential oils was established by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The obtained yields of the essential oils were found to vary greatly in the range of 1.1 to 2.9% (v/w) and the chemical composition varied with the region of collection. A total of 16 compounds were identified. The main compounds were fenchone (16.9 – 34.7%), estragole (2.5 – 66.0%) and trans-anethole (7.9 – 77.7%). The percentages of these three main compounds were used to determine the relationship between the different oil samples and to group them into four different chemotypes: anethole/fenchone; anethole; estragole and anethole/estragole. Antifungal activity of essential oils was evaluated against six food spoilage fungi: Aspergillus niger, A. japonicus, A. oryzae, Fusarium oxysporum, Rhizophus oryzae and R. stolonifer. Antibacterial activity was assessed against three Gram-positive strains: Enterococcus faecalis ATCC 29212...

Interference of heating on the antimicrobial activity and chemical composition of Origanum vulgare L. (Lamiaceae) essential oil

Souza,Evandro Leite de; Stamford,Tânia Lúcia Montenegro; Lima,Edeltrudes de Oliveira; Barbosa Filho,José Maria; Marques,Márcia Ortiz Mayo
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2008 EN
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Origanum vulgare L. (oregano), Lamiaceae, essential oil has a variety of biological properties and its antimicrobial activity has received a renewed interest for use in food conservation. The aim of this study was to evaluate the interference of heating on the antimicrobial activity and chemical composition of O. vulgare essential oil. The antimicrobial activity of the essential oil kept at room temperature and exposed to different heating temperatures (60, 80, 100 and 120 °C during 1 hour) was evaluated by observing antimicrobial effectiveness at absolute concentration and determining MIC values by the solid medium diffusion procedure. The essential oil chemical composition analysis was performed by GC-MS. O. vulgare essential oil showed interesting antimicrobial activity on all assayed microbial strains (Candida albicans, C.krusei, C. tropicalis, Bacillus cereus, Escherichia coli, Staphylococcus aureus, Yersinia enterocolitica, Salmonella enterica, Serratia marcencens), noted by large growth inhibition zones (30-42 mm). Heating treatment showed no significant interference (p < 0.05) on the essential oil antimicrobial activity, noted by the development of microbial growth inhibition zones with similar or close diameters when evaluating the essential oil kept at room temperature and after exposure to different thermal treatments. MIC values oscillated between 10and 40 µL.mL-1 (20µL.mL-1 for most strains). However...

Chemical composition of atmospheric particulate matter soluble fraction and meteorological variables in São Paulo state, Brazil

Bourotte,Christine Laure Marie; Sanchéz-Ccoyllo,Odon Roman; Forti,Maria Cristina; Melfi,Adolpho José
Fonte: Sociedade Brasileira de Meteorologia Publicador: Sociedade Brasileira de Meteorologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 EN
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The objective of this work was to characterize and compare the chemical composition of the PM10 soluble fraction in relation to meteorological variables such as wind direction and air masses backward trajectories. The PM10 was collected during winter of 1999 in two contrasting sites: the São Paulo city and the State Park of Serra do Mar (Cunha) inside the Atlantic Forest Reserve. The aqueous extracts of PM10 were analyzed by Ion Chromatography for major ions (Na+, K+, Mg2+, Ca2+, NH4+, Cl-, NO3-, SO4(2-)) and by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for trace elements (Al, Mn, Fe, Pb, Zn, etc.). In São Paulo, the dominant chemical species were SO4(2-), NO3-, NH4+, Zn, Fe, Al, Ba, Cu, Pb, Mn and Ni while in Cunha, Na+, K+, Cl-, SO4(2-), Zn and Ni were dominant. The chemical composition related to the wind direction during sampling reflected short-range influence due to soil occupation and anthropic activities.

THE EFFECT OF DEPOSITION PARAMETERS ON THE CHEMICAL COMPOSITION AND CORROSION RESISTANCE OF TIC X N Y COATINGS PRODUCED ON HIGH-SPEED STEEL SUBSTRATES

Senna,L.F.; Achete,C.A.; Freire Jr.,F.L.; Hirsch,T.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2001 EN
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TiCxNy coatings deposited on high-speed steel substrates have been used to enhance the tribological properties of cutting tools (hardness, wear resistance, etc.) as well as their corrosion resistance in an aggressive environment. These layers are usually produced by plasma deposition techniques (PVD or CVD), and different coating properties can be obtained with each method. In this work, TiCxNy films were deposited on AISI M2 high-speed steel substrates by the reactive magnetron sputtering technique. A series of samples with a variety of reactive gas mixtures (nitrogen and methane), substrate biases, and deposition temperatures was produced. As a result, coatings with different chemical compositions were deposited for each group of deposition parameters. Gas mixture composition and substrate bias directly affected the chemical composition of the coating, while deposition temperature influenced the chemical composition of TiCxNy layers to a very low extent.

Chemical composition and energy value of guava and tomato wastes for broilers chickens at different ages

Lira,Rosa Cavalcante; Rabello,Carlos Bôa-Viagem; Silva,Edney Pereira da; Ferreira,Paulo Vanderlei; Ludke,Maria do Carmo Mohaupt Marques; Costa,Edgenes Vital
Fonte: Sociedade Brasileira de Zootecnia Publicador: Sociedade Brasileira de Zootecnia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2011 EN
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66.13%
The chemical composition and energy value of guava and tomato wastes for broilers at different ages were determined in this research. The metabolism assays were carried out by using the methodology of total excreta collection to calculate the chemical composition of wastes collected in different months. A total of 270 COBB broiler chicks was used: 150 in the period from 1 to 8 days of age (phase 1) and 120 chicks were used in the period from 10 to 17 days of age (phase 2). The trials were analyzed as completely randomized design with three treatments with five replications of 10 and 8 birds at the respective ages. The treatments consisted of different diets: one reference diet, one with 30% tomato meal and another with 20% guava meal, both partially replacing the reference diet. The values of the chemical composition of guava and tomato wastes varied according to the collection season. The chemical composition indicated that the wastes can be used in poultry feed, but with high crude fiber contents. The values of apparent metabolizable energy and nitrogen-corrected apparent metabolizable energy and of gross energy metabolizability coefficient of guava waste was not affected by the birds age, different from the result observed for tomato waste...

Chemical composition of Pleurotus pulmonarius (Fr.) Quél., substrates and residue after cultivation

Silva,Sueli Oliveira; Costa,Sandra Maria Gomes da; Clemente,Edmar
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2002 EN
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The cultivation of Pleurotus pulmonarius was carried out on different substrate: cotton waste (A) leaves of Cymbopogon citratus (B) and leaves of Panicum maximum Jacq. (C). The mushroom had a varied chemical composition; nevertheless they contained a good composition for to be used as a good source of protein for human kind. The results showed the higher protein content (29.19%) and fibre (9.0%) for the mushroom that were cultivated on cotton peel. The substrate composition and the residue composition after the mushroom harvest were: Protein for the substrate "A" (10.63% and 9.35%), "B" (7.87% and 4.24%) and "C" (7.55% and 5.90 %); Lipids "A" (4.17% and 2.03%), "B"(2.77% and 3.20%) and "C" (0.91% and 2.05%); Fibres "A" (49.02% and 37.02%), "B" (28.40% and 23.26%) and "C" (37.50% and 26.66%) respectively. The substrate "A" showed 0.048% of iron and "C" 0.14% of magnesium, 0.31% of potassium and 0.26% of calcium. In the substrate "B" the quantity of the minerals were very low in comparison to the other substrates. The residues after the harvest of mushroom could be used as fertiliser or as complement in the composition for animal feed.

Chemical composition of Rhodocyclus gelatinosus biomass produced in poultry slaughterhouse wastewater

Ponsano,Elisa Helena Giglio; Lacava,Pedro Magalhães; Pinto,Marcos Franke
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2003 EN
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66.09%
Rhodocyclus gelatinosus R1 grew photoautotrophically in poultry slaughterhouse wastewater inside glass columns (90x670 mm) during 7 days at 31 ± 4ºC, under anaerobiosis and lightness supplied by daylight plus 3 (100W) incandescent and 4 (40W) fluorescent lamps. The culture was centrifuged (4,500xg/20 min) and lyophilized to originate a bacterial biomass with 7.1% moisture content. Chemical composition investigation showed 67.6% crude protein, 27.6% total carbohydrate, 0.6% lipids and 4.2% ash (dry weight). Amino acid composition of the biomass was similar to others described in the literature for Rhodocyclus gelatinosus and for other photosynthetic bacteria. Effluent COD removal after cultivation and elimination of the biomass was around 90%. The valuable chemical composition of Rhodocyclus gelatinosus R1 biomass and the high content in essential amino acids signs for the potential use of the product in poultry feed.

Impact of gamma irradiation on chemical composition of Melissa officinalis L.

Pereira, Eliana; Koike, Amanda; Antonio, Amilcar L.; Barros, Lillian; Ferreira, Isabel C.F.R.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Conferência ou Objeto de Conferência
ENG
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66.09%
Food irradiation is increasingly recognized as an effective decontamination technique that ensures the chemical and organoleptic quality of the product. This decontamination method leads to a reduction in the application of chemical fumigants and preservatives, which are currently used by the food industry in order to provide higher safety for the consumer since it does not leave chemical residues in food. Melissa officinalis L. (commonly known as lemon balm) is used in several countries as aromatic, medicinal herb and also for culinary use. Traditionally it is consumed in infusions for various disorders such as headaches, gastrointestinal disorders (flatulence cramps, spasms and indigestion), nausea, nervousness, anemia, vertigo, syncope, malaise, asthma, bronchitis, amenorrhea, heart failure, arrhythmia, insomnia, epilepsy, depression, psychosis, hysteria, ulcers and wounds; it is also used as anti-bacterial [1-3]. The aim of the present work was to evaluate the effects of different doses of gamma irradiation (0 kGy – control, 1 kGy and 10 kGy) on nutritional value and chemical composition of M. officinalis. The nutritional value was determined according to official analysis procedures. The composition in free sugars...

Expanding the knowledge on chemical composition and antioxidant activity of the Genus Lactarius

Vieira, Vanessa; Barros, Lillian; Martins, Anabela; Ferreira, Isabel C.F.R.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Artigo de Revista Científica
ENG
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66.09%
Despite the presence of toxic compounds in inedible mushrooms, the question whether the chemical nutrients and non-nutrients compositions in edible and inedible Lactarius species are similar remains unanswered. To answer this question, Lactarius citriolens Pouzar and Lactarius turpis (Weinm.) Fr., two inedible species, were studied in order to obtain information about their chemical composition and bioactivity. Free sugars, fatty acids, tocopherols, organic and phenolic acids were analysed by chromatographic techniques coupled to different detectors. L. citriolens and L. turpis methanolic extracts were tested regarding antioxidant potential (reducing power, radical scavenging activity and lipid peroxidation inhibition). The composition of macronutrients varied among the two species, but the profiles were similar between them and among other Lactarius species; L. citriolens gave the highest energy contribution, saturated fatty acids and organic acids, while the L. turpis sample was richer in free sugars, mono- and polyunsaturated fatty acids, tocopherols and phenolic compounds. L. turpis methanolic extract showed the highest antioxidant activity. The absence of hepatoxicity of the methanolic extracts was confirmed in porcine liver primary cells (in vitro conditions). The present study provided new information about wild L. citriolens and L. turpis...

Influência das diferentes granulometrias na composição química das cascas de Eucalyptus globulus Labill., Betula pendula Roth, Picea abies (L.) Karst, Pinus sylvestris L. e Pinus pinea L.; Influence of different particle sizes in the bark chemical composition of Eucalyptus globulus Labill., Betula pendula Roth, Picea abies (L.) Karst, Pinus sylvestris L. e Pinus pinea L.

Mirra, Inês Martins Pereira
Fonte: ISA/UTL Publicador: ISA/UTL
Tipo: Dissertação de Mestrado
Publicado em //2011 POR
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Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia; The goal of this report is to characterize the bark of five industrially important forest species in Europe - Eucalyptus globulus, Betula pendula, Picea abies, Pinus sylvestris e Pinus pinea and to define their potential use as a source of value added chemical products. It was performed the anatomical characterization of bark tissues (dissociated elements), the selective fractionation (size distribution, characterization of particle shape, separation of density and determination of bulk density), the average of basic chemical composition and particle size of three reference fractions (ash, extractives, suberin, Klason lignin, acid soluble lignin, holocellulose and 1% NaOH extraction). The anatomical study shows that there is no differential separation of the cellular elements of the tissues of the bark in seven particle size fractions. The physical process of fractioning showed that, for all barks, over 50% of the mass of material consisted of coarse particles with 6 mm average diameter. On the other hand, there was no direct correlation between the values of bulk density and particle diameter. It has only been possible to separate the birch bark and scots pine by difference in density fluctuations in water. The mean values of the chemical composition brought out that the barks of softwood showed higher content of total extractives...

CHEMICAL COMPOSITION VARIABILITY IN THE Uncaria tomentosa (cat’s claw) WILD POPULATION

Peñaloza,Evelyn Maribel Condori; Kaiser,Samuel; Resende,Pedro Ernesto de; Pittol,Vanessa; Carvalho,Ânderson Ramos; Ortega,George González
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
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Uncaria tomentosa (cat's claw) is a vine widely distributed throughout the South-American rainforest. Many studies investigating the chemical composition of cat's claw have focused on the pentacyclic (POA) and tetracyclic oxindole alkaloids (TOA), quinovic acid glycosides (QAG), and polyphenols (PPH). Nevertheless, it is still uncertain how environmental factors affect chemical groups. The aim of this work was to better understand the influence of environmental factors (geographic origin, altitude, and season) on cat's claw chemical composition. Stem bark, branches and leaf samples were extracted and analyzed by HPLC-PDA. The data obtained were explored by multivariate analysis (HCA and PCA). Higher amounts of oxindole alkaloids and PPH were found in leaves, followed by stem bark and branches. No clear relationship was verified among geographic origin or altitude and chemical composition, which remained unchanged regardless of season (dry or rainy). However, three oxindole alkaloid chemotypes were clearly recognized: chemotype I (POA with cis D/E ring junction); chemotype II (POA with trans D/E ring junction); and chemotype III (TOA). Thus, environmental factors appear to have only a minor influence on the chemical heterogeneity of the cat's claw wild population. Nevertheless...

Application of neural networks in steels' chemical composition design

Dobrzaski,L. A.; Sitek,W.
Fonte: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM Publicador: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2003 EN
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66.09%
Designing of the chemical composition of the steel heats having the demanded properties, e.g. the defined shape of the hardenability curve, is the crucial task from the manufacturing point of view. Rapid development of computer science and technology as well as of modern computer tools, artificial intelligence among them, prompts their increasingly common use in different domains of science and technology. There is a great interest in these methods, which seems justified, since they can be applied both to solving novel problems and to dealing with the ones considered classical. For a couple of years, such trends have been present also in the domain of materials engineering. Contemporary software tools, especially methods of artificial intelligence, make it possible to develop the method, presented in the paper, of designing of the chemical composition of constructional alloy steels, which still are one of the basic groups of metallic engineering materials. It lets the designer abandon the classical approach to the material selection according to which one of the catalogued materials has to be selected. The paper presents the method of designing of the chemical composition basing on the known and the required shape of the hardenability curve with the use of the dedicated neural networks models.

Nutritive evaluation of herbage from permanent meadows by near-infrared reflectance spectroscopy: 1. Prediction of chemical composition and in vitro digestibility

Andrés, Sonia; Giráldez, Francisco Javier; López, Secundino; Mantecón, Ángel R.; Calleja, Alfredo
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artículo Formato: 94510 bytes; application/pdf
ENG
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66.08%
8 pages, 4 tables.-- Available Online Mar 2005.; This study was implemented to evaluate the potential of near-infrared reflectance spectroscopy (NIRS) technology to estimate the chemical composition and in vitro digestibility of botanically complex herbage mixtures characterised, moreover, by a noteworthy variation among samples in the maturity of the forage plants. A total of 107 herbage samples harvested from permanent meadows located in the uplands of Leon (northwestern Spain) were analysed to determine their chemical composition. In addition, the in vitro digestibility of each herbage sample was measured by two different in vitro procedures using buffered rumen fluid. A Bran + Luebbe InfraAlyzer 500 spectrophotometer was used to obtain the near-infrared spectra corresponding to each herbage sample. Prediction equations developed for the estimation of the chemical components showed that NIRS technology could predict these parameters accurately, especially the crude protein and neutral detergent fibre contents (R-adj(2) > 0.95 in both cases). In vitro digestibility parameters could also be predicted with an acceptable degree of accuracy using NIRS technology, particularly the in vitro Tilley and Terry organic matter digestibility (R-adj(2) = 0.925...

Chemical composition of rainwater in northeastern México

RAMÍREZ LARA,E.; MIRANDA GUARDIOLA,R.; GRACIA VÁSQUEZ,Y.; BALDERAS RENTERÍA,I.; BRAVO ÁLVAREZ,H.; SOSA ECHEVERRÍA,R.; SÁNCHEZ ÁLVAREZ,P.; ALARCÓN JIMÉNEZ,A.; TORRES,M. C.; KAHL,J.
Fonte: Centro de Ciencias de la Atmósfera, UNAM Publicador: Centro de Ciencias de la Atmósfera, UNAM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
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The present study reports the chemical composition of atmospheric wet deposition in Monterrey, capital of the state of Nuevo León and the most important industrial city in northeastern México, where air quality presents a serious problem due to dust particles emitted. The sampling period was from January to December 2007. The station was mounted on the roof of the College of Chemical Sciences at the University of Nuevo León which is located in the north of the Metropolitan Area. Thirty-two samples of rain were collected with an automatic sampler and analyzed for pH, ion concentrations (SO4-2, NO3-, Cl-, Ca2+, Na+, K+, NH4+) and conductivity. The results show that the average weighted pH value of the rainwater was 6.58 due to neutralization. Rainwater chemistry showed high contribution of Ca+2 and Mg+2 in cations and SO4-2 and Cl- in anionic species. Low concentration of H+ found in rainwater samples from Monterrey N.L. suggests that an important portion of H2SO4 and HNO3 have been neutralized by alkaline particles in the atmosphere. In order to find possible association between ions in precipitation, and consequently, the possible sources of pollutants correlation study was applied using the program SPSS v.12. Weak correlations were found between the H+ ions and SO4-2 or NO3-1 because of neutralization. The local dust cement factories and surrounding limestone environment might be causing high concentration of Ca+2 and Mg+2. The results of this research will be used to evaluate the composition of atmospheric deposition...

The use of near infrared spectroscopy (NIRS) to predict the chemical composition of feed samples used in ostrich total mixed rations

Swart,E.; Brand,T.S.; Engelbrecht,J.
Fonte: South African Journal of Animal Science Publicador: South African Journal of Animal Science
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
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The wet chemical analysis of feed samples is time consuming and expensive. Near infrared spectroscopy (NIRS) was developed as a rapid technique to predict the chemical composition of feeds. The prediction of accuracy of NIRS relies heavily on obtaining a calibration set which represents the variation in the main population, accurate laboratory analyses and the application of the best mathematical procedures. In this study NIRS was used to determine the chemical composition of total mixed rations (TMRs) used in ostrich diets. A sample population of 479 ostrich feed samples was used in the calibration and 94 samples were used in the independent validation of dry matter (DM), ash, crude protein (CP), ether extract (EE), crude fibre (CF), acid detergent fibre (ADF), neutral detergent fibre (NDF), gross energy (GE), calcium (Ca) and phosphorus (P). Coefficient of determination in validation (r²v) and standard error of prediction (SEP) was satisfactory (r²v values higher than 0.80). Coefficient of determination and SEP values for CP, EE, CF, ADF, NDF and GE were 0.97% and 0.74%, 0.89% and 0.50%, 0.94% and 1.41%, 0.89% and 2.67%, 0.95% and 2.81% and 0.80% and 0.28 MJ/kg, respectively. Less accurate values (r²v below 0.80) were obtained for DM...