PEDRO EITI AOKI
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Artigo IPEN-doc 26224 Evaluating a primary wastewater treatment plant, numerical analysis of experimental data2019 - BURGOS, MANUEL R.; AOKI, PEDRO E.The plant under study is processing the wastewater of the eastern part of Montevideo city, capital of Uruguay, its population is approximately one million people, its maximum capacity is 3 m3/s. The goal of the experiment was to determine the mean residence time, MRT, of the wastewater in the decanting tanks. The plant has four of these tanks of approximately 500 m3 each. The output of this system of decanting tanks is pumped to a 2.300 m length pipe into the River Plate. At the plant input a set of mechanical filters is used and after it the material is pumped to a central 25 m length distributor, where the entrances of the decanting tanks are placed. For evaluating the whole system, it was used about 740 MBq (20 mCi) of 131I in 10 ml as an input pulse. The analysis was performed in two steps. Initially the distributor was studied, a transfer function from the main input to the entrance of each tank was determined. In the second step, the goal of the plant evaluation, the MRT of each tank was analyzed. Considering the non-impulsive shape of the input function of the decanting tanks, a numerical deconvolution software of the output-input of each tank was developed ab initio. Deconvolution results of various sequences as: main input to the distributor system-decanting tanks entrances-output were compared with meaningful conclusions.Artigo IPEN-doc 25777 Gallium-67 citrate used as a tracer of acetone production routes2019 - MESQUITA, C.H. de; CALVO, W.A.P.; AOKI, P.E.; SILVA, V.C. da; HARAGUCHI, M.I.; VELO, A.F.; ALVAREZ, A.G.; HAMADA, M.M.In this work the pathway of the chemical product and the kinetics parameters were evaluated in a laboratory plant settled, using 0.4 GBq (10 mL) of 67Ga citrate as radiotracer and 18 NaI(Tl) radiation detectors. The AnaComp program was used to estimate the kinetic para ameters of the acetone production. The yield of the acetone production was estimated by the percentage ratio between the areas under the curve (AUC) of the curve profiles of the final product compartment divided by the concentration found inside the chemical reactor whose result was 87% yield during the first 30 minutes of reaction.Artigo IPEN-doc 24163 Gallium-67 citrate used as a tracer of acetone production routes2017 - MESQUITA, CARLOS H. de; CALVO, WILSON A.P.; AOKI, PEDRO E.; SILVA, VALDIR C. da; HARAGUCHI, MARCIO I.; VELO, ALEXANDRE F.; ALVAREZ, ALEXANDRE G.; PAIXAO, LETICIA B.; HAMADA, MARGARIDA M.In this work the pathway of the chemical product and the kinetics parameters were evaluated in a laboratory plant settled, using 40 GBq of 67Ga citrate as radiotracer and 18 NaI(Tl) radiation detectors. The AnaComp program was used to estimate the kinetic parameters of the acetone production. The yield of the acetone production was estimated by the percentage ratio between the areas under the curve (AUC) of the curve profiles of the final product compartment divided by the concentration found inside the chemical reactor whose result was 87% yield during the first 30 minutes of reaction.Resumo IPEN-doc 23061 Industrial applications of the IEA-R1 research reactor in Brazil2017 - GENEZINI, F.; CALVO, W.A.P.; FERNANDO, A.J.; MARRA NETO, A.; AOKI, P.E.The IEA-R1 is an open pool type research reactor located at theNuclear and Energy Research Institute (IPEN-CNEN/SP) site and achieved its first criticality on September 16, 1957. IEA-R1 is the largest research reactor in operation in Brazil, with a core composed of 24 fuel elements with 20% enriched uranium silicide, 4 control rods (AgInCd) and many irradiation positions supplying thermal neutron fluxes ranging from 1012 to 1014 n/cm2s. Currently, IEA-R1 is operating at 4:5 MW on an 8 hours per day and 4 days per week cycle. The IEA-R1 reactor is a multipurpose facility used for basic and applied research in nuclear and for the production of radioisotopes for industry and nuclear medicine. For industry, IEA-R1 produces radiotracers and sealed radioactive sources (60Co and 192Ir) for industrial -radiography, as well as doped silicon by neutron transmutation. For radiotracer production, IEA-R1 has been working with a compact local staff (3 persons) and is assisted by the Radiation Technology Centre at IPEN-CNEN/SP, in which there are installed hot cells for high activity handling. Most of the radiotracers produced at IEA-R1 are irradiated in a quartz bulb inside an aluminium vessel; the only exception is for 41Ar production, where a special device that doesn’t require a hot cell is used. These are the radiotracers produced at IEA-R1 and their applications in industry and environment: • 203Hg: determination of the mercury mass immobilized in electrolytic cells from soda and chlorine producing industries (46:6 days and 0:28 MeV). • 131I and 82Br: flow rate measurement and residence time distribution (RTD) studies in rivers, lakes and wastewater treatment plants (8:04 days and 36 h, 0:36 MeV and 0:55 MeV, respectively). • 192Ir: environmental studies, in the form of a premixed sand (glass powder plus activated iridium), to study drag sediment in river (73:8 days and 0:32 MeV). • 198Au: representative study, in real conditions, of the impact of great civil works for the construction of important artificial harbour, airport and hydroelectric reservoir, by labelling sand to be removed from the bottom with emulsion of gold (2:7 days and 0:41 MeV). • 41Ar and 79Kr: study the gas phase of fluidized cracking catalytic plants (110 min and 35 h, 1:29 MeV and 0:51 MeV, respectively). • 140La: study the solid phase (catalysts) of fluidized cracking catalytic plants in petroleum refineries (40 h, 1:16 MeV). For doped silicon production, a device that affords the best axial and radial uniformity of the neutron dose is used. These doping uniformities as well as the doping accuracy are determined using resistivity values, showing an excellent doping quality. A recent improvement was the development of an irradiation system to produce gaseous radioisotopes (41Ar and 79Kr), delivering the activated gases directly into the shield bottle without handling and dose exposition for operators, instead of via small quantities (batches), through quartz ampoules containing these noble gases.Publicação IPEN-doc 03085 Determinacao da vazao solida por arrasto de fundo no Rio Parana utilizando tracador radioativo1988 - AOKI, P.E.; ENOKIHARA, C.T.; ROCCA, H.C.C.; BITTENCOURT, A.V.L.Publicação IPEN-doc 00590 Measurement of flow and direction of ground water by radioactive tracers: hydrological evaluation of a waste disposal site at 'Instituto de Pesquisas Energeticas e Nucleares (IPEN)'1981 - CHANDRA, U.; AOKI, P.E.; SILVA, J.A.R.; CASTAGNET, A.C.Publicação IPEN-doc 03010 Determinacao de perfis de concentracoes de cesio-137 nos focos principais do acidente radiologico ocorrido em GoianiaGO1988 - ROCCA, H.C.C.; AOKI, P.E.; ENOKIHARA, C.T.; ROSTELATO, M.E.C.M.; LEPKI, V.; BAMBALAS, E.Resumo IPEN-doc 05822 Determination of groundwater recharge in Abadia de Goias, Goias state, by application of artificial tritium tagging method1995 - POLI, D.C.R.; AOKI, P.E.; LEPKI, V.; SAAD, S.; ARAUJO, L.; PEDROSO, G.A.Resumo IPEN-doc 05281 Determinacion de recambio de aguas subterraneas en Abadia de Goias, Estado de Goiania, por aplicacion del metodo de atrito marcado artificialmente1993 - POLI, D.C.R.; AOKI, P.E.; LEPKI, V.; SAAD, S.; ARAUJO, L.; PEDROSO, G.A.Resumo IPEN-doc 02224 The use of nuclear techniques in environment1993 - SAMPA, M.H.O.; POLI, D.C.R.; LIMA, W.; OSSO JUNIOR, J.A.; AOKI, P.E.
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