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Hematological problems are associated with Coronavirus disease 2019 (COVID-19). Respiratory impairment is the higher point studied, although without experimental studies related to the oxygen transport performed by erythrocytes. Therefore, we decided to investigate if erythrocytes from COVID-19 patients have their functionality changed. The case-control study included hospitalized patients with a positive real-time polymerase chain reaction (RT-PCR) result admitted to University Hospital. Volunteers (negative RT-PCR results) were recruited as a control group. Thus, we assessed different erythrocytes parameters, oxidative stress markers, and biophysical studies using whole blood and isolated hemoglobin. We found a decrease of 51% in oxygen uptake and reduced antioxidant enzyme activity in COVID-19 patients compared to controls. Raman spectrometry showed structural changes in the hemoglobin and lipids of the erythrocytes from COVID-19 patients; thus, these results were consolidated with an increase in Young’s modulus in erythrocytes followed by morphology changes. Besides, isolated hemoglobin from COVID-19 patients has a distinct interaction profile using a ligand model compared to the control. COVID-19 leads to structural, functional, and morphological damage to human erythrocytes. Our data showed structural and molecular changes and induction of oxidative stress in erythrocytes by COVID-19, a new perspective on the contribution of erythrocytes to a respiratory commitment in COVID-19.

https://doi.org/10.21577/0103-5053.20230031

Antiproliferative activity of essential oils from three plants of the Brazilian Cerrado: Campomanesia adamantium (Myrtaceae), Protium ovatum (Burseraceae) and Cardiopetalum calophyllum (Annonaceae)
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Alves, C. C. F.

; Oliveira, J. D.

; Estevam, E. B. B.

; Xavier, M. N.

; Nicolella, H. D.

; Furtado, R. A.

; Tavares, D. C.

; Miranda, M. L. D.

Brazilian Journal of Biology

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jun 2020, Volume 80 N. 2 Pages 290 - 294

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

Resumo Os óleos essenciais podem ser extraídos de várias partes das plantas e apresentam diversas atividades biológicas. O Cerrado brasileiro possui uma grande variedade de plantas produtoras de óleos essenciais muitas delas ainda não estudadas. Levando-se em consideração a biodiversidade desse bioma, o objetivo deste trabalho foi avaliar a atividade antiproliferativa dos óleos essenciais extraídos de três espécies de plantas ocorrentes no Cerrado do estado de Goiás: Campomanesia adamantium (Cambess.) O. Berg, Protium ovatum (Engl. in Mart.) e Cardiopetalum calophyllum (Schltdl.). Os óleos essenciais foram obtidos das folhas de C. adamantium e C. calophyllum e das folhas e frutos verdes de P. ovatum por hidrodestilação, usando o aparelho do tipo Clevenger. A composição química dos óleos essenciais foi determinada pelo método de Cromatografia Gasosa acoplada à Espectrometria de Massas (CG-EM). Os constituintes químicos majoritários identificados nos óleos essenciais estudados foram: β-mirceno (62,00%), espatulenol (28,78%), germacreno-B (18,27%), óxido de β-cariofileno (16,40%), β-cariofileno (14,00%), α-pineno (11,30%), viridiflorol (9,99%), limoneno (7,30%) e (Z,E)-farnesol (6,51%). A atividade antiproliferativa foi avaliada em diferentes linhagens de células tumorais humanas: adenocarcinoma de mama (MCF-7), adenocarcinoma cervical (HeLa) e gliobastoma (M059J), além de, uma linhagem celular humana normal (GM07492A, fibroblastos pulmonares). O óleo essencial das folhas de C. adamantium exibiu menores valores de CI50 em todas as linhagens celulares tumorais avaliadas, sendo menores que aquele obtido na linhagem celular normal, indicando seletividade. Este é o primeiro relato da atividade antiproliferativa dos óleos essenciais de C. adamantium , P. ovatum e C. calophyllum contra células tumorais humanas.

Abstract Essential oils, which may be extracted from several parts of plants, have different biological activities. The Brazilian Cerrado has a large variety of plants that yield essential oils, even though many have not been studied yet. Taking into account the biodiversity of this biome, this study aimed at evaluating the antiproliferative activity of essential oils extracted from three species of plants of the Cerrado in Goiás state: Campomanesia adamantium (Cambess.) O. Berg, Protium ovatum (Engl. in Mart.) and Cardiopetalum calophyllum (Schltdl.). Essential oils were extracted from both C. adamantium and C. calophyllum leaves and from P. ovatum leaves and green fruits by hydrodistillation carried out by a Clevenger-type apparatus. The chemical composition of the essential oils was determined by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The following major chemical constituents were identified in the essential oils under investigation: β-myrcene (62.00%), spathulenol (28.78%), germacrene-B (18.27%), β-caryophyllene oxide (16.40%), β-caryophyllene (14.00%), α-pinene (11.30%), viridiflorol (9.99%), limonene (7.30%) and (Z,E)-pharnesol (6.51%). The antiproliferative activity was evaluated in different human tumor cell lines: breast adenocarcinoma (MCF-7), cervical adenocarcinoma (HeLa) and glioblastoma (M059J). A normal human cell line was included (GM07492A, lung fibroblasts). Results showed that essential oils from C. adamantium leaves got the lowest values of IC50 in all strains of tumor cells under evaluation. They were significantly lower than the ones of the normal cell line, an evidence of selectivity. It is worth mentioning that this is the first report of the antiproliferative activity of essential oils from C. adamantium , P. ovatum and C. calophyllum against human tumor cells.

https://doi.org/10.1590/1519-6984.192643 776 downloads

Lipid Profile Determination by Direct Infusion ESI-MS and Fatty Acid Composition by GC-FID in Human Milk Pools by Folch and Creamatocrit Methods
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Rydlewski, Adriela A.

; Silva, Patrícia D.

; Manin, Luciana P.

; Tavares, Christyna B. G.

; Paula, Meliana G.

; Figueiredo, Ingrid L.

; Neia, Vanessa B. M. J. C.

; Santos, Oscar O.

; Visentainer, Jesuí V.

Journal of the Brazilian Chemical Society

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may 2019, Volume 30 N. 5 Pages 1063 - 1073

Abstract: En | Text: En | PDF: En

Human milk (HM) is extremely important to the baby, containing a varied and balanced range of nutrients fundamental to the ideal development of the newborn. Among these nutrients, HM lipids provide 40-60% of the energy. In HM banks, the creamatocrit method is employed as a quick and solvent-free tool, however, since Folch methodology is considered reference for lipid extraction, this study compared the fatty acid (FA) composition and the lipid profile by gas chromatography with flame ionization detector (GC-FID) and direct infusion by electrospray ionization mass spectrometry (DI-ESI-MS) in pools of different HM phases, obtained from Folch and creamatocrit methods, in order to elucidate which method provides better information about HM lipids. Lipid compositon results by Folch were superior to the results obtained by creamatocrit in HM pools investigated. It means, the lipid profiles of all HM pools were more intense, and the number of FA identified by Folch was also higher in comparison to the creamatocrit method (21 and 6 FAs, respectively). GC-FID analysis in combination with principal component analysis (PCA) divided the methods, confirming a greater contribution of the Folch method. Therefore, Folch methodology revealed an effective lipid extraction in comparison to creamatocrit method.

https://doi.org/10.21577/0103-5053.20190006 731 downloads

New records of crustaceans infesting Phractocephalus hemioliopterus (Siluriformes: Pimelodidae), the large catfish from the Amazon
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Oliveira, Marcos Sidney B.

; Corrêa, Lincoln L.

; Gonçalves, Raissa A.

; Neves, Lígia R.

; Prestes, Luiza

; Ferreira, Drielly O.

; Tavares-Dias, Marcos

Revista mexicana de biodiversidad

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2019, Volume 90 elocation e901969

Abstract: En Es | Text: En Es | PDF: En | PDF: Es

Abstract The aim of the present study was to investigate the infracommunities of ectoparasitic crustaceans in Phractocephalus hemioliopterus Bloch and Schneider, 1801, a catfish from the lower Amazon River, in the state of Pará, eastern Amazon region, Brazil. From 12 hosts examined, a total of 45 specimens of crustacean ectoparasites from 5 species were found in the tegument, oral cavity or dorsal fins. The species were: Argulus multicolor, Argulus violaceus, Dolops nana, Dolops discoidalis, and Braga patagonica. Dolops discoidalis was the dominant ectoparasite, while D. nana had the highest mean intensity in the tegument, which was the most infested host site. This is the first record of A. multicolor, A. violaceus, D. nana and B. patagonica parasiting P. hemioliopterus.

Resumen El objetivo del presente estudio fue investigar las infracomunidades de crustáceos ectoparásitos en Phractocephalus hemioliopterus Bloch y Schneider, 1801, un bagre de la parte baja del río Amazonas, en el estado de Pará, en la Amazonía oriental, Brasil. A partir de 12 hospederos examinados, se encontraron un total de 45 ejemplares de crustáceos ectoparásitos de 5 especies en el tegumento, cavidad o aletas dorsales orales. Las especies fueron: Argulus multicolor, Argulus violaceus, Dolops nana, Dolops discoidalis y Braga patagonica. Dolops discoidalis fue el ectoparásito dominante, mientras que D. nana tuvo la intensidad media más alta en el tegumento, que fue el sitio más infestado. Este es el primer registro de A. multicolor, A. violaceus, D. nana y B. patagonica parasitando P. hemioliopterus.

https://doi.org/10.22201/ib.20078706e.2019.90.1969 305 downloads

Brazilian legislation on genetic heritage harms Biodiversity Convention goals and threatens basic biology research and education
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ALVES, RUY JOSÉ V.

; WEKSLER, MARCELO

; OLIVEIRA, JOÃO A.

; BUCKUP, PAULO A.

; POMBAL JR., JOSÉ P.

; SANTANA, HÉLCIO R.G.

; PERACCHI, ADRIANO LÚCIO

; KELLNER, ALEXANDER W.A.

; ALEIXO, ALEXANDRE

; LANGGUTH, ALFREDO

; ALMEIDA, ALZIRA MARIA P. DE

; ALBERNAZ, ANA LUISA

; RIBAS, CAMILA C.

; ZILBERBERG, CARLA

; GRELLE, CARLOS EDUARDO V.

; ROCHA, CARLOS F.D.

; LAMAS, CARLOS JOSÉ E.

; HADDAD, CÉLIO F.B.

; BONVICINO, CIBELE R.

; PRADO, CYNTHIA P.A.

; LIMA, DANIELA O. DE

; ROSSA-FERES, DENISE C.

; SANTOS, FABRÍCIO R. DOS

; SALIMENA, FÁTIMA REGINA G.

; PERINI, FERNANDO A.

; BOCKMANN, FLÁVIO A.

; FRANCO, FRANCISCO LUÍS

; GIUDICE, GISELE M.L. DEL

; COLLI, GUARINO R.

; VIEIRA, IMA CÉLIA G.

; MARINHO-FILHO, JADER

; WERNECK, JANE M.C.F.

; SANTOS, JORGE A.D. DOS

; NASCIMENTO, JORGE LUIZ DO

; NESSIMIAN, JORGE LUIZ

; CORDEIRO, JOSÉ LUIS P.

; CLARO, KLEBER DEL

; SALLES, LEANDRO O.

; CASATTI, LILIAN

; PY-DANIEL, LUCIA HELENA R.

; SILVEIRA, LUÍS FÁBIO

; TOLEDO, LUÍS FELIPE

; OLIVEIRA, LUIZ F. DE

; MALABARBA, LUIZ ROBERTO

; SILVA, MARCELO D. DA

; COURI, MÁRCIA S.

; MARTINS, MÁRCIO

; TAVARES, MARCOS D.S.

; SOBRAL, MARCOS EDUARDO G.

; VIEIRA, MARCUS VINÍCIUS

; OLIVEIRA, MARIA DE LOURDES A.

; PINNA, MÁRIO DE

; HOPKINS, MICHAEL J.G.

; SOLÉ, MIRCO

; MENEZES, NAÉRCIO A.

; PASSOS, PAULO

; D’ANDREA, PAULO SERGIO

; PINTO, PEDRO C.E.A.

; VIANA, PEDRO L.

; TOLEDO, PETER M.

; REIS, ROBERTO E.

; VILELA, ROBERTO

; BASTOS, ROGÉRIO P.

; COLLEVATTI, ROSANE G.

; CERQUEIRA, RUI

; CASTROVIEJO-FISHER, SANTIAGO

; CARAMASCHI, ULISSES

Anais da Academia Brasileira de Ciências

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apr 2018, Volume 90 N. 2 Pages 1279 - 1284

Abstract: En | Text: En | PDF: En

https://doi.org/10.1590/0001-3765201820180460 7311 downloads

INFLUENCE OF THE PLOTS FORMAT ON THE PERFORMANCE INDEX OF THE SOYBEAN COMBINE HARVESTER
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Paixão, Carla S. S.

; Voltarelli, Murilo A.

; Silva, Rouverson P. Da

; Tavares, Tiago De O.

; Gírio, Lucas A. Da S.

Engenharia Agrícola

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sep 2017, Volume 37 N. 5 Pages 961 - 972

Abstract: En | Text: En | PDF: En

ABSTRACT: The intensive mechanization during the harvest operation and success of this operation depends on several factors, one of which is the length and format of the plots. The aim of this study was to evaluate the operating performance of a soybean harvester in different geometric plots shape, using as quality indicators performance parameters by means of statistical control tools of process. The experiment was conducted in March 2014 in the city of Uberaba - MG. Operational capacity was evaluated in the mechanical harvesting of soybeans in three plots: irregular, rectangular and trapezoidal. Performance evaluations of soybean harvester were made from the following parameters: displacement speed, engine rotation, cylinder rotation and concave opening. The grain water contents affect the quality indicators of the soybean harvester performance in all plots shapes. The harvester performance is considered able to maintain between the specification limits and close to the target, to speed quality indicators the irregular and the trapezoidal plots and for cylinder rotation the trapezoidal plot.

https://doi.org/10.1590/1809-4430-eng.agric.v37n5p961-972/2017 5368 downloads

MONITORING OF SOYBEAN MECHANICAL HARVESTING AS A FUNCTION OF PLOT SHAPES
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Paixão, Carla S. S.

; Alcântara, Aline S.

; Voltarelli, Murilo A.

; Silva, Rouverson P. da

; Tavares, Tiago de O.

Engenharia Agrícola

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aug 2017, Volume 37 N. 4 Pages 689 - 698

Abstract: En | Text: En | PDF: En

ABSTRACT: Information on harvester performance is important in the management and optimization of mechanized agricultural systems. In this sense, the aim of this study was to monitor the operation quality of soybean mechanical harvesting in different plot shapes by means of statistical process control. The harvest was carried out in an agricultural area of a farm located in Uberaba, MG, Brazil, with an experimental design based on the assumptions of statistical quality control and 18, 28, and 24 replications for irregular, rectangular, and trapezoidal plots, respectively. The variables and/or quality indicators of harvester performance were forward speed, engine speed, cylinder speed, and concave opening. The lowest variation occurred in the irregular plot for the quality indicators forward speed and engine speed of harvester. Engine speed and the concave opening of harvester were unstable for all plot shapes. Only the cylinder speed of the soybean harvester presented process stability during operation for the three plot shapes.

https://doi.org/10.1590/1809-4430-eng.agric.v37n4p689-698/2017 668 downloads

EFFECTIVE POWER AND HOURLY FUEL CONSUMPTION DEMANDED BY SET TRACTOR- COFFEE HARVESTER IN FUNCTION OF ADEQUACY TRACTOR BALLASTING
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Tavares, Tiago de O.

; Damasceno, André F.

; Voltarelli, Murilo A.

; Silva, Rouverson P. da

; Furlani, Carlos E. A.

Engenharia Agrícola

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aug 2017, Volume 37 N. 4 Pages 699 - 708

Abstract: En | Text: En | PDF: En

ABSTRACT: The mechanized gathering process of sweeping coffee is extremely important to reduce the losses of fruit not used in the harvesting operation. But this operation usually has a low operational performance and a high cost per unit collected in this way any measures that can effectively reduce costs increase the viability of the operation. In this sense, studies on adequacy tractor mass for each operation show improvement in energy use, reducing fuel consumption. So, this study aimed to quantify the fuel consumption and effective power along the process of a tractor 4x2 FWD pulling the coffee harvester. I was used as treatments three ballasting settings, these being equivalent the relations power to weight of 36, 39 and 42 kg hp-1 working with and without activated FWD, randomized statistically, with 10 repetitions each configuration. It was conclude that, at low power-weight ratio, the front wheel drive assist had no significant influence on the hour fuel consumption. Already in the configuration with higher ratio, the use of front wheel drive favored in reducing fuel consumption and better energy use.

https://doi.org/10.1590/1809-4430-eng.agric.v37n4p699-708/2017 1118 downloads

Monitoring of mechanical sugarcane harvesting through control charts
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Voltarelli, Murilo A.

; Silva, Rouverson P. da

; Zerbato, Cristiano

; Paixão, Carla S. S.

; Tavares, Tiago de O.

Engenharia Agrícola

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dec 2015, Volume 35 N. 6 Pages 1079 - 1092

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

RESUMO O controle estatístico de processo aplicado em operações agrícolas mecanizadas representa uma nova maneira de avaliar a qualidade com que as operações são realizadas. Neste sentido, objetivou-se neste trabalho comparar três tipos de ferramentas do controle estatístico de processo aplicadas às perdas na colheita mecanizada de cana-de-açúcar, para determinar qual o melhor modelo de carta de controle a ser utilizado para este indicador de qualidade. O monitoramento das perdas na colheita mecanizada foi realizado diariamente nas áreas agrícolas, de uma unidade produtora na região do Triângulo Mineiro - MG, durante o período de 70 dias, na safra de 2014. Ao final do período de avaliação, foram coletados 194 pontos amostrais no total, para cada tipo de perda analisado. As cartas de controle utilizadas foram: carta de valores individuais, média móvel e média móvel exponencialmente ponderada. Os indicadores de qualidade avaliados durante a colheita de cana-de-açúcar foram as perdas do tipo: rebolo inteiro, tocos, pedaço fixo, cana inteira, lascas, pedaços soltos e totais. A carta de controle de valores individuais é a melhor opção para o monitoramento das perdas na colheita mecanizada de cana-de-açúcar, por apresentar maior facilidade na interpretação dos resultados, em relação às demais.

ABSTRACT Statistical process control in mechanized farming is a new way to assess operation quality. In this sense, we aimed to compare three statistical process control tools applied to losses in sugarcane mechanical harvesting to determine the best control chart template for this quality indicator. Losses were daily monitored in farms located within Triângulo Mineiro region, in Minas Gerais state, Brazil. They were carried over a period of 70 days in the 2014 harvest. At the end of the evaluation period, 194 samples were collected in total for each type of loss. The control charts used were individual values chart, moving average and exponentially weighted moving average. The quality indicators assessed during sugarcane harvest were the following loss types: full grinding wheel, stumps, fixed piece, whole cane, chips, loose piece and total losses. The control chart of individual values is the best option for monitoring losses in sugarcane mechanical harvesting, as it is of easier result interpretation, in comparison to the others.

https://doi.org/10.1590/1809-4430-Eng.Agric.v35n6p1079-1092/2015 2070 downloads

10.

In vitro efficacy of oil from the seed of Carapa guianensis (andiroba) in the control of Felicola subrostratus
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Barros, Fabíola N. de

; Farias, Márcia P. O.

; Tavares, Juliana P. C.

; Alves, Leucio C.

; Faustino, Maria A. da G.

Revista Brasileira de Farmacognosia

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oct 2012, Volume 22 N. 5 Pages 1130 - 1133

Abstract: En | Text: En | PDF: En

This study was perfomed to assess the in vitro effect of oil from the seed of andiroba (Carapa guianensis Aubl.) on Felicola subrostratus (Burmeister, 1838) (Mallophaga: Trichodectidae). Six hundred specimens of F. subrostratus from neighborhood of Jordão, Recife-PE, Brazil, were collected by hand directly from the fur of cats infested naturally. The lice were transported in plastic recipients to the Laboratory of Parasitic Diseases of Domesticated Animals of the Department of Veterinary Medicine of the Universidade Federal Rural de Pernambuco (Brazil) for the immersion test. Four dilutions of andiroba oil (100, 50, 25 and 10%) in distilled water were tested, using Tween 80 as dispersant; two control groups (one with distilled water and the other with monosulfiram) were also formed; four replicates were performed, with 25 specimens for each dilution, totaling 100 lice per treatment. After the test, the insects were kept at room temperature and observed for mortality rates for 72 h. The biological activity of the product achieved 100% mortality of the insects in the first hour at concentrations of 100 and 50% and in the third hour at concentrations of 25 and 10%. The results demonstrate the possibility of controlling F. subrostratus throught the use of oil extracted from andiroba seeds.

2195 downloads

11.

Residual stress measurement using the contour and the sectioning methods in a mig weld: Effects on the stress intensity factor
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Richter-Trummer, Valentin

; Tavares, Sérgio M. O.

; Moreira, Pedro M. G. P.

; Figueiredo, Miguel A. V. de

; Castro, Paulo M. S. T. de

Ciência & Tecnologia dos Materiais

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jan 2008, Volume 20 N. 1-2 Pages 114 - 119

Abstract: Pt En | Text: Pt En | PDF: Pt | PDF: En

A distribuição longitudinal de tensões residuais de uma placa fina em alumínio 6082-T6, soldada topo-a-topo por arco eléctrico, foi determinada com o método contour. Mesmo tendo esta técnica sido aplicada a várias geometrias distintas, os autores desconhecem a sua aplicação a uma placa de secção fina como a apresentada no presente trabalho. A validação dos resultados foi efectuada através de resultados obtidos na literatura, incluindo o procedimento CEGB-R6, e também através do já conhecido método experimental de seccionamento. A medição de tensões residuais foi utilizada na previsão do crescimento de uma fenda de fadiga, com o intuito de comparar o comportamento ao de uma fenda a crescer na mesma placa livre de tensões residuais.

The longitudinal residual stress distribution in a 6082-T6 aluminum alloy MIG butt welded thin plate was determined using the contour method. Although several geometries have been successfully studied with the contour method before, the authors are not aware of previous attempts to use this method in a long narrow section as in the present case. Validation was done using literature data including the CEGB-R6 procedure as well as experimental plate surface measurements obtained using the established sectioning technique. The residual stress measurement was used in fatigue crack growth simulations in order to compare the fatigue behavior of the plate with and without residual stress.

1086 downloads

12.

Photofissility at 1 GeV for nuclei throughout the periodic table
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Tavares, O. A. P.

; Duarte, S. B.

; Morcelle, V.

; Deppman, A.

Brazilian Journal of Physics

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sep 2005, Volume 35 N. 3b Pages 915 - 918

Abstract: En | Text: En | PDF: En

A new approach to evaluate nuclear photofissilities at incident photon energies above the pion photoproduction threshold has been recently developed and proved to describe successfully the fissilities of natPb and 232Th target nuclei at energies ~0.2-4.0 GeV. The method is merely a simple, semiempirical description of the photofission reactions in which fissility, f, is governed by two basic quantities, namely, i) the first-chance fission probability, $\bar{f}_1$, for the average cascade residual, and ii) the slope, $\bar{s}$, of the chance-fission probability associated with the average evaporative sequence of fissionable residuals. In the present work we have extended this approach to analyse photofissity data that have been accumulated over the past fourty years or so, measured at 1 GeV, for nearly fourty target nuclei extending from Ti up to Np. Results have shown that the variation of fissility with Z²/A could be described quite satisfactorily by the proposed model.

902 downloads

13.

The utilization of crisp code in hybrid reactor studies
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Anéfalos, S.

; Deppman, A.

; Silva, G.

; Maiorino, J. R.

; Santos, A. dos

; Duarte, S. B.

; Tavares, O. A. P.

; Garcia, F.

Brazilian Journal of Physics

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sep 2005, Volume 35 N. 3b Pages 912 - 914

Abstract: En | Text: En | PDF: En

One of the main applications of the Hybrid Reactors (ADS - Accelerator Driven System) is the incineration of transuranics (TRU) by fast neutrons that emerge from a spallation source in a sub critical reactor waste burner [1, 2]. For this application, an accurate description and prediction of spallation reaction is necessary, including all the characteristics concerning spatial and energetic angular distributions, spallation products and neutron multiplicity. To describe the nuclear reactions at intermediate and high energies, Monte Carlo calculations have been used. The CRISP package considers the intranuclear cascade (INC) that occurs during the spallation process in a realistic time-sequence approach in which all particles inside the nucleus can participate in the cascade and the nuclear density fluctuations are naturally taken into account during the process. The occupation number of each single particle level is considered as a function of time and a more realistic Pauli blocking mechanism can be performed. None of the existing models have effectively used all those features. The evaporation of protons and alpha particles are taken into account making possible the correct prediction of fissilities of actinides and pre-actinides [3]. Another implementation is the NN single-pion production reaction. This reaction is especially relevant if one is interested in neutron or proton multiplicities, since the creation/emission of pions is directly related with the excitation energy of the residual nucleus. We will present some results obtained with the CRISP package for proton-nucleus reaction at intermediate and high energies. This package was obtained by the coupling of the MCMC [4] and MCEF [5] codes, with the introduction of some improvements, such as better Pauli blocking mechanism, which constrains the residual nucleus energetic evolution to the Pauli Principle from the ground-state to the final compound-nucleus formed at the end of the intranuclear cascade process, and introduction of the most relevant resonant excitation and the NN single pion production channel. The results of interest for ADS development are consistent with the experimental data at different proton energies. More detailed calculations are being performed for studying other features of proton-nucleus reactions and with different targets.

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14.

New approach to nuclear photofission reactions above 0.15 GeV
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Tavares, O. A. P.

; Duarte, S. B.

; Deppman, A.

; Likhachev, V. P.

Brazilian Journal of Physics

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sep 2004, Volume 34 N. 3a Pages 924 - 928

Abstract: En | Text: En | PDF: En

A simple approach to evaluate nuclear photofissilities at energies above the pion photoproduction threshold has been developed. It is based on the current, two-step model for intermediate-energy photonuclear reactions, i.e. a photon-induced intranuclear cascade followed by a fission-evaporation competition process for the excited, post-cascade residual nucleus. The calculation method (semiempirical by nature) shows that fissility (i.e., total fission probability) is governed by two basic quantities, namely, the first-chance fission probability for the average cascade residual, and a parameter which defines an evaporative sequence of residuals in which the average, equivalent chance-fission probabilities of nuclides belonging to the same generation are located. The natPb photofissility data measured recently in the range ~ 0.2 - 3.8 GeV at the Thomas Jefferson Laboratory could be explained very satisfactorily by the present approach.

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15.

Developement of crisp package for spallation reaction studies and its utilization in ADS (Accelerator Driven System)
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Anéfalos, S.

; Deppman, A.

; Arruda-Neto, J. D. T.

; Likhachev, V.P.

; Santos, A. dos

; Coelho, P. R. P.

; Duarte, S. B.

; Tavares, O. A. P.

Brazilian Journal of Physics

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sep 2004, Volume 34 N. 3a Pages 966 - 968

Abstract: En | Text: En | PDF: En

The progress of nuclear physics had allowed a better understanding of nuclear structure and reaction mechanisms, but also enables important applications of nuclear energy in our modern way of life. We can point out those ones related to power generation from nuclear reactors, providing an almost inexhaustive power source due to the huge quantities of nuclear fuel existent in our planet, which guaranties its utilization for thousands of years. The main interest is the so-called Hybrid Reactors (ADS - Accelerator Driven System), in which the reactor has a sub critical core and the chain reaction is sustained by an external source that comes from spallation reactions induced by high energy protons (about 1 GeV) from an accelerator, producing a large number of secondary particles (mainly neutrons). For those applications, precise knowledge about nuclear structure and nuclear reaction characteristics is needed.

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