RESUMOA interação do riacho dos Macacos e de uma bateria de poços, na sua vizinhança, em Juazeiro do Norte-CE, foi avaliada segundo parâmetros físicos, químicos e bacteriológicos. Foram realizadas também análisés de oxigênio-18 a fim de avaliar a mistura de águas subterrâneas com águas superficiais. Verificou-se que o riacho dos Macacos, na maioria dos parâmetros analisados, não se enquadra em nenhuma das classes de águas doces da Resolução N° 357 do CONAMA e da Portaria N° 518 do Ministério da Saúde. Constatou-se que neste riacho e no lago da Timbaúba a concentração de coliformes totais e termotolerantes é extremamente elevada. Uma simulação computacional do transporte advectivo do contaminante de partículas do rio para o aqüífero com o modelo MODPATH/MOFLOW revela tempos mínimos de transito do manancial superficial poluído até os filtros dos poços entre 15 e 100 dias. Considerando a meia vida dos coliformes em águas subterrâneas de aproximadamente 8 dias e sua alta concentração na água superficial, contaminação dos poços de abastecimento é inevitável.
PALAVRAS-CHAVE:Qualidade de água, contaminação de mananciais, simulação do transporte advectivo. Norte-Ceará, was
ABSTRACT
The interaction of the Macacos Creek and a neighboring well field, in Juazeiro do
The performance of microstrip antennas using composite thick films of (BTOBaTiO 3 ) and CCTO (CaCu 3 Ti 4 O 12 ) as a substrate were studied. The dielectric permittivity and loss of (BTO) x -(CCTO) 1Àx thick films with x 5 0, 0.2, 0.5, 0.8, 0.9, and 1 were examined. These films were prepared in two-layer geometry using the screen-printing technique on Al 2 O 3 substrates. Mechanical alloying followed by the solid-state procedure was successfully employed to produce powders of CCTO (CaCu 3 Ti 4 O 12 ) used in the films. We also studied the films dielectric permittivity (K) and loss (D) in the medium-frequency (MF) range (100 Hz to 1 MHz). The performance of a planar microstrip antenna that uses the (BTO) x :(CCTO) 1Àx thick films as a substrate of high K was also examined in the microwave range of frequencies. From the analysis of the antenna operation of the samples, one can conclude that the higher values of K in the range of 2.5-3.3 GHz antennas is presented by the BTO substrates. For the BTO film, the K value is ;66 (2.6 GHz) and decreases to 34 for the CCTO film (3 GHz). For the BTO and CCTO films, the antenna bandwidths (BW) are ;50% and ;38%, respectively. The higher bandwidth presented by the BTO compared to the CCTO is certainly associated with the higher loss presented by the BTO phase, which is a ferroelectric phase. Therefore, these measurements confirm the potential use of such materials for small microwave planar antennas, where the miniaturization of the devices is crucial.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.