REGINA BECK TICIANELLI

REGINA BECK TICIANELLI

Página do item completo

Resultados de Busca

Agora exibindo 1 - 8 de 8

Multi-element contamination in soils from major mining areas in Northeastern of Brazil
2021 - MONTALVAN-OLIVARES, D.M.; SANTANA, C.S.; VELASCO, F.G.; LUZARDO, F.H.M.; ANDRADE, S.F.R.; TICIANELLI, R.B.; ARMELIN, M.J.A.; GENEZINI, F.A.
Mining has become one of the main factors in the global biogeochemical cycle of potentially toxic elements. Therefore, it is considered one of the anthropogenic activities with the greatest negative impact on the environment. These impacts are maximized in semiarid regions, where mining activities can lead to soil degradation and decrease in land productivity. This study aimed to assess the level of contamination in natural, urban, and agricultural soils of three important mining areas, where approximately 80,000 people live, and pollution levels have never been determined before. For this purpose, soil samples were collected around iron, uranium, and vanadium mines, as well as in the main human settlements of the region. The concentrations of 34 elements were determined by instrumental neutron analysis activation (INAA) and inductively coupled plasma optical emission spectrometry (ICP OES) techniques. Pollution indices (CF, EF, mCd, PLI, and REEP) revealed that there is a moderate to heavy level of pollution for 89% of the analyzed elements. Additionally, an extreme contamination level was observed in 78% of the samples, for at least one element. Statistical analyses were performed to identify patterns in the distribution and common sources of pollution. The results suggest that the concentrations for Al, Ba, Hf, Na, Pb, Rb, REE, Ta, Th, U, Zn, and Zr are associated with geogenic causes. However, the influence of anthropogenic sources such as agriculture and mining on the accumulation of these elements in soils should not be disregarded. In contrast, the contents of As, Br, Cd, Co, Cr, Cs, Cu, Fe, K, Mn, Ni, Sc, Ti, and V reflect the direct impact of anthropogenic sources.
Evaluation of the uncertainty associated with sample holders in NAA measurements in LAN/IPEN
2019 - ZAHN, G.S.; TICIANELLI, R.B.; SAIKI, M.; GENEZINI, F.A.
In IPEN’s Neutron Activation Laboratory (LAN/IPEN), thin stainless steel sample holders are used for gamma spec-trometry in NAA measurements. This material is very practical, but its chemical composition may be troublesome, as it presents large amounts of elements with intermediate atomic number, with attenuation factors for low-energy gamma-rays that must not be neglected. In this study, count rates obtained using different sample holders were compared. To accomplish that, an Am-241 source, with 59-keV gamma emission, was used so that low-energy gamma attenuation differences can be determined. Moreover, in order to study the energy dependence of these differences, a Ho-166m source was also used. From these results, it was possible to analyze the experimental error associated to the variations between sample holders, with the aim of introducing an addictive term to the uncertainty analysis of comparative Neu-tron Activation Analysis results.
Long-term performance assessment of HPGE detectors used in the neutron activation analysis laboratory of IPEN-CNEN/SP (Brazil)
2017 - ZAHN, G.S.; GENEZINI, F.A.; TICIANELLI, R.B.; SAIKI, M.
In this work, verification data for 11 HPGe detectors from two different manufacturers and three different intrinsic configurations were analyzed in respect to the stability of both the efficiency and resolution for the 122 keV peak from 57Co and the 1332 keV peak from 60Co. The results allow a discussion about the stability of these parameters over time (in some cases, almost 15 years), their sensitivity to imminent detector failures and their performance after a failure has been corrected; moreover, the results show a clear correlation between the manufacturer or configuration and the long-term performance of the detector.
A Brazilian coal fly ash as a potential source of rare earth elements
2017 - LANGE, CAMILA N.; CAMARGO, IARA M.C.; FIGUEIREDO, ANA MARIA G.M.; CASTRO, LILIANA; VASCONCELLOS, MARINA B.A.; TICIANELLI, REGINA B.
Rare earth elements (REEs) have several applications and their market demands have increased. Recently, coal fly ash (CFA) has been considered as a source of these elements. The purpose of this study was to evaluate the REEs content in a CFA from a Brazilian coal power plant by instrumental neutron analysis, to classify it according to commercial purposes and to assess the weathering impact in the REEs content, since it is held in fields nearby the power plant. The results pointed no significant REEs leachability and indicated this CFA as a promising REEs source.
Can robust statistics aid in the analysis of NAA results?
2015 - ZAHN, GUILHERME S.; GENEZINI, FREDERICO A.; SECCO, MARCELLO; TICIANELLI, REGINA B.; FIGUEIREDO, ANA M.G.
Determination of trace elements in Tillandsia usneoides by neutron activation analysis for environmental biomonitoring
2001 - FIGUEIREDO, A.M.G.; SAIKI, M.; TICIANELLI, R.B.; DOMINGOS, M.; ALVES, E.S.; MARKERT, B.
The use of Tillandsia unsneoides L. as bioindicator of air pollution in Sao Paulo, Brazil
2004 - FIGUEIREDO, A.M.G.; ALCALA, A.L.; TICIANELLI, R.B.; DOMINGOS, M.; SAIKI, M.
Metals and semi-metals in street soils of São Paulo city, Brazil
2012 - RIBEIRO, ANDREZA P.; FIGUEIREDO, ANA M.G.; TICIANELLI, REGINA B.; NAMMOURA NETO, GEORGES M.; SILVA, NATALIA C.; KAKAZU, MAURICIO H.; ZAHN, GUILHERME