Papers by Edilene Ferreira
Revista ESPACIOS, Aug 25, 2017
Revista em Agronegócio e Meio Ambiente, Mar 26, 2021
A desidratação de frutas é um mercado promissor e pouco explorado no Brasil. Um dos principais pr... more A desidratação de frutas é um mercado promissor e pouco explorado no Brasil. Um dos principais problemas da remoção da água das frutas é a perda de qualidade em função das alterações estruturais, por conta do elevado teor de água. Objetivou-se neste trabalho analisar a contração volumétrica durante a secagem de bagas de uva ‘Itália’. Os frutos foram submetidos à secagem em condições controladas de temperaturas (60 e 70 ºC) até atingir teor de umidade final de equilíbrio do ar. Foram construídas as curvas de secagem, determinadas propriedades físicas, o índice de contração volumétrica e o ajuste de modelos matemáticos às curvas de secagem e de contração volumétrica. O tempo de secagem perdurou 38 e 48 horas para as temperaturas de 60 e 70 ºC, quando atingiram teores de umidade próximos a 20% (base seca). Houve maior contração volumétrica das bagas sob temperatura de 70 ºC. O modelo matemático que melhor se ajustou à análise de contração volumétrica a 60 ºC foi o modelo de Corrêa et al. (2011) e o de exponencial a 70 ºC.
Considering the Information Society and the need for learning the English language (EL), we can s... more Considering the Information Society and the need for learning the English language (EL), we can see that the learning of this curriculum component is not satisfactory, since students cannot express themselves in real communication situations. The educational literature points to the integration of Information and Communication Technologies (ICTs) as educational tools towards a meaningful learning. Therefore, the general purpose of the present research is to analyze the pedagogical use of ICTs in the teaching and learning of the EL, based on the daily practice of high school teachers. Thus, we performed a bibliographical research on the teaching of the EL in Brazil and on ICTs. Then, we carried out a documentary research, analyzing the Political-pedagogic Project (PPP) of the research field school, comparing it with the curriculum benchmarks. The empirical research was developed according to the qualitative method, through a case study in a primary and secondary public school of Paraiba, located in Cajazeiras. The analysis of data was based on the confrontation of theorists such as Pierre Levy (2000), Manuel Castells, (2006), Libâneo (2000 and 2003), among others, who point out to the use of ICTs as educational tools, the curriculum benchmarks and the speech of the investigated actors. As data collection instrument, we used the semi-structured interview technique with teachers, in order to describe their profile, especially, with regard to education, their conceptions and practices. We also applied questionnaires to students, as an attempt to draw their profile, as well as their expectations and perceptions. Our analysis reveals that the school does not effectively use digital technology, but we can observe the integration of other technologies to teaching practice. The statements of the investigated actors point to the ratification of our assumptions, as they consider ICTs as elements which can boost the teaching and learning process. We highlight that, although students recognize the daily presence of the EL and the importance of this curriculum component to their education, they have not achieved a satisfactory performance, what makes them to be excluded from the Information Society. In this regard, we point out that laws and guidelines are not sufficient. Aspects related to teachers' continuing education should also be considered, so that they can update their pedagogical practice face to the new educational requirements.
Atomic Spectroscopy, 2021
Honey is a natural food that is valued worldwide for its nutritional and therapeutic values. Ther... more Honey is a natural food that is valued worldwide for its nutritional and therapeutic values. Therefore, authentication of honey according to the geographical origin is a guarantee of the genuine properties. In this article, an evaluation of spark discharge-assisted laser-induced breakdown spectroscopy (SD-LIBS) for certification of the geographical origin of honey is reported. Forty-nine samples of multifloral honey produced in four Argentine provinces were considered. The results showed the best classification performance was obtained using smoothing, generalized least squares weighting (GLSW) and mean centering for spectral preprocessing, added to the k-nearest neighbor (k-NN) or Support Vector Machine (SVM) classification algorithms, which provided 100% of correct classification. More importantly, the results of Partial Least Squares-Discriminant Analysis (PLS-DA) pointed to N, Ca, K, Cu, Fe and Mn as key elements for the certification of geographical origin. In addition, the greatest potential of N stands out for the discrimination of the origin of honey. These findings confirm SD-LIBS as a promising tool for authentication of honey quality, providing a simple, fast and environmentally friendly solution. The method can be useful for industry, the market and others related to food authenticity.
Anais do II Congresso Brasileiro de Fluidodinâmica Computacional, 2018
A aquicultura tem aumentado intensamente nos últimos anos e para alcançar o desenvolvimento que s... more A aquicultura tem aumentado intensamente nos últimos anos e para alcançar o desenvolvimento que se espera, muitos desafios precisam ser superados, a exemplo da utilização da água, alvo de preocupação mundial. Os biofiltros de areia fluidizada possuem tecnologia eficiente e competitiva em termos de custos para a remoção de resíduos dissolvidos nesses tipos de sistemas. O objetivo deste trabalho é utilização da ferramenta computacional para simular um biofiltro de leito fluidizado, subsidiando o entendimento das variáveis importantes neste escoamento. A modelagem foi realizada utilizando-se a abordagem Euleriana-Euleriana e a Teoria Cinética de Escoamento Granular. Os resultados obtidos foram expressos através da análise de pressão e da fração volumétrica nos diferentes tempos analisados.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2017
New methods are proposed for the determination of Mo, Ni, Co, and V in soils using high-resolutio... more New methods are proposed for the determination of Mo, Ni, Co, and V in soils using high-resolution continuum source graphite furnace atomic absorption spectrometry with direct solid sampling. Cobalt and V were simultaneously determined, and different analytical lines of Ni and V were monitored to adjust sensitivity for each sample. Accuracy was checked by means of soil certified reference materials, and also by flame atomic absorption spectrometry as comparative technique. The results for Mo, Ni, Co, and V found by proposed methods were in agreement with certified values and with those obtained by the comparative technique at 95% confidence level. The concentrations found in different soil samples were in the ranges 0.19-1.84 mg kg −1 (Mo), 9.2-22.7 mg kg −1 (Ni), 1.1-10.7 mg kg −1 (Co), and 35.6-426.1 mg kg −1 (V). The relative standard deviations were in the ranges 3.2-10% (Mo), 2.8-9.8% (Ni), 4.0-9.2% (Co), and 1.2-8.0% (V). The limits of quantification for Mo, Ni, Co, and V were 0.027, 0.071, 0.15, and 1.43 ng, respectively.
Akropolis Revista De Ciencias Humanas Da Unipar, 1994
O lixo hospitalar tem sido considerado como um problema de saude publica. Seu destino, desde sua ... more O lixo hospitalar tem sido considerado como um problema de saude publica. Seu destino, desde sua producao ate seu condicionamento final vem sendo estudado exaustivamente. Os aterros sanitarios e os incineradores, com os seus pros e contras, serao discutidos neste artigo.
The Journal of Physical Chemistry B, 2009
In this work, we investigated the P-O bond cleavage of dianionic p-nitrophenyl phosphate monoeste... more In this work, we investigated the P-O bond cleavage of dianionic p-nitrophenyl phosphate monoester (p-NPP), with attack of aqueous methylamine on phosphorus, by using the hybrid quantum mechanical/effective fragment potential (QM/EFP) approach. We explored the structures, energetic properties, reaction mechanism, and charge distribution along the entire reaction coordinate. Our B3LYP/6-31++G(d,p)/EFP results show that the cleavage of the P-O bond of p-NPP proceeds through a concerted mechanism with an activation energy of about 26 kcal/mol and an activation free energy at 39 degrees C of 23.6 kcal/mol, in good agreement with the experimental value of 27 kcal/mol. The reaction involves a trigonal bipyramidal (TBP) transition state with less initial bonding to the nucleophile than to the leaving group. The extent of the P-O(nitrophenolate) bond dissociation at the transition state, with methylamine as the nucleophile, is less than that with OH(-). The computed charge distribution along the reaction coordinate is consistent with a progressive charge transfer from the nitrogen atom of methylamine to the phosphate unit along the reaction coordinate. A new strategy to build the initial EFP cluster, by running a classical Monte Carlo simulation and analyzing the center-of-mass radial pair distribution function, was also used.
Cadernos de …, 2011
Resumo: Buscando avaliar o efeito de agroecossistemas de várzea no cenário de mudanças climáticas... more Resumo: Buscando avaliar o efeito de agroecossistemas de várzea no cenário de mudanças climáticas, quanto aos mecanismos associados à regulação dos fluxos dos gases de efeito estufa, este trabalho teve como objetivo quantificar a emissão de óxido nitroso em solos de várzea, no município do Rio de Janeiro, na região de Santa Cruz. A área tem predomínio de Organossolos seguidos por Gleissolos. A coleta de gases foi realizada por meio da implantação de caixas metálicas vedadas no solo, onde foi feita a coleta e transferência do ar para frascos de vidro e analisado por cromatografia gasosa. Os resultados mostram variação da emissão de N2O em função da umidade do solo e do espaço poroso saturado por água. Em geral, os maiores valores de emissão de N2O ocorreram na primeira coleta, quando foi registrada maior média de temperatura. Palavras-Chave: Organossolos, matéria orgânica, óxido nitroso.
Journal of Chemical Theory and Computation, 2008
Temperature-dependent conformational population calculations for anti and gauche forms of 1,2-dic... more Temperature-dependent conformational population calculations for anti and gauche forms of 1,2-dichloroethane and 1,2-difluorethane were carried out at a highly correlated level of theory (MP4(SDTQ) and CCSD(T)) employing good quality basis sets (6-311++G(3df,3pd) and aug-cc-pVQZ) for the determination of gas relative conformational energies, making use of the statistical thermodynamics formalism for the evaluation of the thermal energy correction at the MP2/6-311++G(3df,3pd) and MP2/aug-cc-pVTZ levels. In addition to the standard calculation of thermodynamic partition functions, a treatment of the lowest-frequency vibrational mode as hindered rotation and anharmonic correction to vibrational frequencies was also included. We found a good agreement between ab initio calculated conformational population values and experimental gas-phase electron diffraction data for the 1,2-dicloroethane. However, for the 1,2-difluorethane species, a reasonable agreement with the experimental anti/gauche population ratio obtained from the analysis of gas-phase far-infrared (50-370 cm-1) and low-frequency Raman (70-300 cm-1) spectra was not obtained. The results reported here indicate that, for 1,2-difluorethane, and probably other substituted alkanes where the gauche effect is of relevance, a more appropriated treatment of the low-frequency modes must be pursued in order to reproduce experimental conformational population data.
International Journal of Quantum Chemistry, 2009
Density functional theory (DFT) calculations with different exchange‐correlation functionals were... more Density functional theory (DFT) calculations with different exchange‐correlation functionals were performed for a mixed valence Fe(II)/Fe(III) binuclear complex with μ‐methoxo and two μ‐carboxylate bridging ligands, (1) with geometry optimizations being performed for all possible spin multiplicities (MS = 2, 4, 6, 8, and 10). Within the exchange‐correlation functionals studied, only the hybrid GGA functionals B3P and B3LYP and also the pure GGA functional RPBE, predicts the geometry with high spin (S = 9/2) to be more stable than the geometry with low spin state (S = 1/2) by 20 kcal/mol, in agreement with the experimental findings. These functionals also predict the same stability order for the different spin states, being MS = 10>8>6>2>4. The meta‐GGA functionals TPSS and TPSSh and also the pure GGA functionals BLYP and BP86 predict different stability orders. The computed average EPR g‐tensor, gav, of 2.03, at the B3LYP level, is in good agreement with the experimental...
International Journal of Quantum Chemistry, 2006
Quantum chemical methods were used for the theoretical determination of the conformational popula... more Quantum chemical methods were used for the theoretical determination of the conformational population for the relevant conformers of cyclononane, i.e., TBC, TCB, TCC, and M4 (or C1), which have been previously investigated experimentally through detailed examination of the nuclear magnetic resonance (NMR) spectrum. Our best Gibbs free energy result, evaluated with MP4(SDTQ)/6‐31G(d,p)//MP2/6‐31G(d,p) energy differences and MP2/6‐31G(d,p) thermal corrections, lead to a temperature‐dependent population in excellent agreement with the experimental results based on the analysis of the low temperature 13C NMR spectrum. The nice agreement with experiment is achieved using MP2 harmonic frequencies for the evaluation of vibration partition functions within the standard statistic thermodynamics formalism. Theoretical temperature‐dependent infrared (IR) and 13C NMR spectra were simulated and compared with experimental data, which confirmed the ab initio conformational population reported here...
International Journal of Quantum Chemistry, 2012
We report MP4(SDTQ) and CCSD(T) ab initio temperaturedependent conformational populations for a s... more We report MP4(SDTQ) and CCSD(T) ab initio temperaturedependent conformational populations for a series of cycloalkanes with increasing ring size, cycloundecane (11-C), cyclododecane (12-C), and cyclotridecane (13-C), using extended basis sets. Our aim is to analyze the commonly used quantum chemical procedure for evaluating the thermal energy contribution to Gibbs free energy particularly the adequacy of standard harmonic oscillator vibrational partition function for large molecular systems. Experimental population data for cycloundecane, obtained from low temperature (90.1 K) 13 C NMR, and cyclododecane, from gas phase electron diffraction experiment at 393.15 K, are available, and we found a good agreement with MP4(SDTQ) and CCSD(T) ab initio calculated conformational population. Our results indicate that the procedure of considering all 3N-6 vibrational modes as harmonic oscillators seems adequate for the prediction of the preferred conformer of cycloundecane, cyclododecane, and cyclotridecane, in the absence of a more appropriate approach to treat the low frequency modes that is applicable for large molecules. Therefore, it can be expected to work satisfactorily in room temperature conformational analysis studies on large molecules containing a great number of vibrational frequencies below 625 cm À1 , such as in supramolecular chemistry, biological, and material science applications. V
... Ao Diretor-Presidente das FIP por todas as oportunidades a mim concedidas. As amigas pesquisa... more ... Ao Diretor-Presidente das FIP por todas as oportunidades a mim concedidas. As amigas pesquisadoras: Antônia Zélia Dantas de Assis e Aretuza Candeia de Melo, pela ajuda no Pré-Projeto de Dissertação. Ao amigo Pe. Everaldo ...
Dalton Trans., 2010
In this study, four new mononuclear copper(ii) complexes, [Cu(L(1))(dpq)]ClO(4) (), [Cu(L(1))(phe... more In this study, four new mononuclear copper(ii) complexes, [Cu(L(1))(dpq)]ClO(4) (), [Cu(L(1))(phen)]ClO(4) (), [Cu(L(2))(dpq)]ClO(4) (), [Cu(L(1))(OAc)] (), and the known complex [Cu(dpq)(2)(H(2)O)]ClO(4) (), were synthesized and characterized by various methods (dpq = dipyrido[3,2-d:2',3'-h]quinoxaline, L(1) = (3,5-di-tert-butyl-2-hydroxybenzyl)(2-pyridylmethyl)imine, L(2) = (2-hydroxybenzyl)(2-pyridylmethyl)imine). The structure of [Cu(L(1))(dpq)]ClO(4) () was determined by X-ray crystallography and reveals that the Cu(II) center is coordinated by dpq and by the N(2)O donor ligand L(1) in a distorted square pyramidal arrangement. The interaction of with calf thymus DNA was measured and the binding constant K(b) was obtained for the complexes, with values strongly dependent on the intercalating and/or binding properties of the ligands present in the structure of each complex. Also, the nuclease and photonuclease activity in terms of plasmid DNA cleavage with addition of reactants was monitored, in order to verify the mechanism through which the complexes cleave DNA. The complexes displayed good activity under both UV (365 nm) and red light (635 nm) irradiation, with the Type II mechanism prevailing in the case of the former and Type I mechanism for the latter. Finally, two new correlations between the experimental and theoretical parameters are discussed and some hypotheses regarding the active species generation are proposed.
Computational and Theoretical Chemistry, 2012
Density Functional Theory (DFT) calculations using the hybrid meta-GGA TPSSh functional, were car... more Density Functional Theory (DFT) calculations using the hybrid meta-GGA TPSSh functional, were carried out for mixed valence compounds Fe(III)-M(II) (M = Fe, Cu, Ni, Co and Mn) which are structural and functional biomimetic models for Purple Acid Phosphatases. The broken symmetry (BS) formalism was used to compute the magnetic coupling constant which shows that all complexes exhibit weak antiferromagnetic coupling. The effect of the geometry on the accuracy of the BS calculations is evaluated and it is shown that the TPSSh functional provides accurate results with errors in the range of 10-19%, as long as the geometry around the transition metal ions is well described. All complexes show one magnetic exchange r/p pathway involving the in-plane p-orbitals of the phenoxo bridge and the metal d-orbitals. Additionally, a correlation between the computed coupling constant and the M II-O(bridge) bond distance is found, in agreement with the experimental findings.
Chemistry - A European Journal, 2008
Introduction Dihydroorotase (DHO) catalyzes the reversible interconversion of dihydroorotate and ... more Introduction Dihydroorotase (DHO) catalyzes the reversible interconversion of dihydroorotate and carbamoyl aspartate as illustrated in Scheme 1. [1] This transformation is a key step in the de novo biosynthesis of pyrimidine nucleotides, and thus, DHO is an attractive target for inhibitor design and mechanistic interrogation. [2] Amino acid sequence comparisons have demonstrated that DHO is a member of the amidohydrolase superfamily (AHS) of enzymes. [3] The AHS is a group of enzymes that catalyze primarily hydrolytic reactions in a wide range of substrate contexts. [4] All members of the AHS possess a (b/a) 8-barrel structural fold with an active site that resides at the C-terminal end of the b barrel. [4] The hydrolytic water molecule is activated for nucleophilic attack by coordination to a mononuclear or binuclear metal center. The divalent cations that have been found ligated to the active sites within these enzymes include Zn 2 + , Ni 2 + , and Fe 2 +. [4] However, Mn 2 + , Cd 2 + , and Co 2 + will activate some of these enzymes under certain conditions. [5] The X-ray crystal structure of DHO from Escherichia coli has been determined to high resolution and has a binuclear zinc cluster at the active site. [6, 7] Remarkably, when the protein was crystallized in the presence of substrate at a pH at which the equilibrium constant for the enzymatic reaction was near unity, dihydroorotate was found bound to the active site of one monomeric unit of the dimeric protein, whereas carbamoyl aspartate was bound to the adjacent
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Papers by Edilene Ferreira