128 research outputs found

    Utilization of the Corncob Agro-Industrial Residue as a Potential Adsorbent in the Biosorption of Bisphenol-A

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    The presence of plastic waste in water bodies has led to a growing concern due to the impact on human health. Among the most important plastic additive molecules is bisphenol-A (BPA). On the other hand, micro-pollutant removal processes that make use of agro-industrial waste have aroused the interest of researchers. This is because the accumulation of lignocellulosic materials is also an environmental problem. The objective of this work is to use corncob agro-industrial residue (CC) as an adsorbent in the removal of BPA in aqueous matrix. The adsorption studies were carried out in reaction media containing the ground vegetable fiber and BPA solution in concentrations of 10, 25 and 50 mg L-1, as well as at pHs 3, 5, 7 and 9. Isotherms models and kinetic models were evaluated. The results showed that CC is a potent BPA adsorbent in aqueous solution, leading to about 90% of removal. The adsorption kinetics followed the pseudo-second order model and isotherm that best suited was the Lagmuir model, and the maximum adsorption capacity was 51.25 mg per gram of adsorbent fiber, after 20 min of contact. The thermogravimetric analysis allowed us to conclude that CC is a material resistant to high temperatures, due to the presence of a considerable amount of lignin. Finally, the best results of BPA removal efficiency by CC compared to activated carbon corroborate its high biosorption capacity

    Uso de biofertilizante líquido na produção de alfafa

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    bitstream/CNPAB-2010/27430/1/doc151.pd

    Aproveitamento das entrelinhas de cana-de-açúcar para produção de grãos de caupi (Vigna unguiculata L. Walp)

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    bitstream/CNPAB-2010/27429/1/doc150.pd

    Thin Domain Walls in Lyra Geometry

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    This paper studies thin domain walls within the frame work of Lyra Geometry. We have considered two models. First one is the thin domain wall with negligible pressures perpendicular and transverse direction to the wall and secondly, we take a particular type of thin domain wall where the pressure in the perpendicular direction is negligible but transverse pressures are existed. It is shown that the thin domain walls have no particle horizon and the gravitational force due to them is attractive.Comment: 8 pages, typos are corrected, published Astrophysics and Space Sciences 305, 337 (2006

    Incidencia natural de parasitoides em ovos de percevejos (Hemiptera: Pentatomidae) encontrados na soja no Distrito Federal.

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    Um levantamento das especies de parasitoides de ovos de pentatomideos presentes na soja foi realizado em Planaltina, DF. Doze especies de parasitoides de ovos (Telenomus edessae Fabricius, Telenomus podisi Ashmead, Telenomus sp.; Trissolcus basalis (Wollaston), Trissolcus brochymenae Ashmead, Trissolcus sp., Trissolcus teretis Johnson, Trissolcus urichi Crawford; Anastatus auriceps Ashmead, Eupelmus sp., Ooencyrtus sp. e Neorileya sp.) foram encontradas em sete especies de percevejos em soja: Acrosternum aseadum Rolston, Edessa meditabunda (Fabricius), Euschistus heros (Fabricius), Nezara viridula Linnaeus, Piezodorus guildinii (Westwood), Podisus nigrispinus (Dallas) e Thyanta perditor (Fabricius). Registrando-se, pela primeira vez, a ocorrencia de novos hospedeiros de A.auriceps (A.aseadum); T. teretis (E.heros e T.perditor); T.urichi (A.aseadum, P.guildinii e P.nigrispinus)

    Efeito da aplicação de nitrogênio, sob a forma de chorume bovino, na qualidade e produção do pasto Tanzânia (Panicum maximum).

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    bitstream/CNPAB-2010/32766/1/doc192.pd

    Agricultural machinery adequacy for handling the mombaça grass biomass in agroforestry systems.

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    Abstract: The current scenario of Agroforestry Systems (AFS) worldwide lacks specific machinery, resulting in practically all operations being carried out manually. This leads to a significant physical effort for small-scale farmers and limits the implementation of AFS to small areas. The objective of the study was to evaluate the suitability of existing machines for performing agroforestry tasks. This research utilizes Descriptive Statistics and Exponentially Weighted Moving Average methods to evaluate the data and compare the treatments, where different machines are used to cut Mombaça grass (Megathyrsus maximus Jacq): (i) costal brushcutter (CBC); (ii) tractor-mounted rotary brushcutter (RBC); and (iii) mini grain reaper machine (GRM). The experiments were conducted in Jaguariúna, São Paulo, Brazil. GRM is recommended for achieving greater biomass production, reducing raking time, and minimizing operational costs. CBC is suitable for smaller areas due to its affordability and slow operation, which requires significant physical effort. RBC is recommended for reducing working time, physical effort, and personnel costs, making it suitable for larger-scale contexts
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