2,996 research outputs found

    SWINE WASTE PHYTOREMEDIATION USING DUCKWEED (Landoltia punctata, Les & Crawford) IN A FULL SCALE PLANT

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    Banner Apresentado em Congresso: 11th International Conference, Heraklion, Crete, Greece PhytotechnologiesThe large amount of nitrogen and phosphorous compounds found in pig manure has caused ecological imbalances, with eutrophication of major river basins in the producing regions. Therefore, the aquatic macrophytes group named duckweeds (Araceae; Lemnoideae) have been successfully used for phytoextraction and rhizodegradation of nutrient and heavy metals from swine waste, generating further a biomass with high protein content. The present study evaluated the phytoremediation of nitrogen and phosphorus from swine waste using the duckweed Landoltia punctata and also their protein biomass production as by-product

    Improving a position controller for a robotic joint

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    There are several industrial processes that are controlled by a PID or similar controller. In robotics it is also usual the need of position control of joints. Tune a controller is the process to obtain the gains that optimise the behaviour of the system while maintaining its stability and robustness. This paper presents an approach of tuning a speed controller using the Internal Model Control (IMC) method and a position controller using the second order Bessel prototype while testing in different controllers methodology, such as PID, Cascade and feedforward combination with dead zone compensation. In order to compare the controllers, results for an Hermite reference position will allow to validate the proposed solution.info:eu-repo/semantics/publishedVersio

    New approach for beacons based mobile robot localization using kalman filters

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    New approaches on industrial mobile robots are changing the localization systems from old methods such as magnetic tapes to laser beacons based systems and natural landmarks since they are more adaptable and easier to install on the shop floor. Sensor fusion methods needs to be applied since there is information provided from different sources. Extended Kalman Filters are very used in the pose estimation of mobile robots with sensors that detect beacons and measure its distance and angle in a local referential frame. In certain situations, like for example wheels slippage, the number of impulses read for the encoders is wrong, resulting in a very large displacement or rotation and causing a bad estimation at the end of the prediction step. This bad estimation is used for the linearization of the non-linear equations, causing a bad linear approximation and probably a failure in the Kalman Filter. In this paper it is demonstrated that if we use the last state estimation calculated in the update step at the last cycle, instead of the estimation from the prediction step in the actual cycle, the result is an estimator much more robust to errors in the odometry information. Simulated and real results from several experiments are illustrated to demonstrate this new approach.This work is co-financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 and the Lisboa2020 under the PORTUGAL 2020 Partnership Agreement, and through the Portuguese National Innovation Agency (ANI) as a part of project PRODUTECH SIF: POCI01-0247-FEDER-024541. This work is financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme, and by National Funds through the Portuguese funding agency, FCT - Fundac¸ao para a Ci ˜ encia e a Tecnolo- ˆ gia, within project SAICTPAC/0034/2015- POCI-01-0145- FEDER-016418.info:eu-repo/semantics/publishedVersio

    Using full-scale duckweed ponds as the finish stage for swine waste treatment with a focus on organic matter degradation

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    Artigo Publicado em: IWA - Water Science & TechnologyThe rapid increase in the number of swine has caused pronounced environmental impacts worldwide, especially on water resources. As an aggregate, smallholdings have an important role in South American pork production, contributing to the net diffusion of pollution. Thus, duckweed ponds have been successfully used for swine waste polishing, mainly for nutrient removal. Few studies have been carried out to assess organic matter degradation in duckweed ponds. Hence, the present study evaluated the efficiency of two full-scale duckweed ponds for organic matter reduction of swine waste on small pig farms. Duckweed ponds, in series, received the effluent after an anaerobic biodigester and storage pond, with a flow rate of 1 m3 day 1. After 1 year of monitoring, an improvement in effluent quality was observed, with a reduction in biochemical oxygen demand (BOD) and total chemical oxygen demand (tCOD), respectively, of 94.8 and 96.7%, operating at a loading rate of approximately 27 kgBOD ha 1 day 1 and 131 kgCOD ha 1 day 1. Algae inhibition due to duckweed coverage was strongly observed in the pond effluent, where chlorophyll a and turbidity remained below 25 μg L 1 and 10 NTU. Using the study conditions described herein, duckweed ponds were shown to be a suitable technology for swine waste treatment, contributing to the environmental sustainability of rural areas
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