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Sahu N.,University of Delhi | Singh R.B.,University of Delhi | Kumar P.,University of Delhi | Silva R.V.D.,Federal University of Fronteira sul | Behera S.K.,Japan Agency for Marine - Earth Science and Technology
Advances in Meteorology | Year: 2013

The extremely high-streamflow events of the Paranaíba River basin are found to be associated with La Niña phenomenon during December-February (DJF). Extreme events are identified based on their persistent flow for seven days and more after taking retention time into consideration. The extremely high-streamflow events are associated with the La Niña years; 80% of the high-streamflow events have occurred during La Niña phases. Therefore, a very-significant 80% and above correspondence of the La Niña events and the seasonal streamflow anomalies are found in DJF. Although climate variations have direct relationship with the rainfall, streamflow variations are considered as the surrogates to rainfalls. However, apart from climate variations the anthropogenic and land-use changes also influence streamflow variations. In this study, we have applied multivelocity TOPMODEL approach and residual trend analysis to examine the impact of land-use to the streamflow at the Fazenda Santa Maria gauge stations. However, the model residual trend analysis of the TOPMODEL approach cannot quantify the extent of land-use impact. Thus, La Niña phase is important components to understand and predict the streamflow variations in the Paranaíba River basin. © 2013 Netrananda Sahu et al. Source


Bieseki L.,Federal University of Rio Grande do Norte | Treichel H.,Federal University of Fronteira sul | Araujo A.S.,Federal University of Rio Grande do Norte | Pergher S.B.C.,Federal University of Rio Grande do Norte
Applied Clay Science | Year: 2013

Montmorillonite clay was treated with hydrochloric acid and subsequently pillared with aluminum polyoxocations. The acid-treated samples were evaluated for the removal of structural elements (Al, Fe and Mg) and for conservation of the lamellar organization. The more severe the treatment, the greater the specific area obtained. Despite the loss of structural organization, all samples were pillared, with a displacement of peak (001) to 2θ lower angles. The pillaring of all acid-treated samples promoted an increase in the specific area of these materials. Pillared samples previously treated at 50°C with HCl concentrations of 2 and 4molL-1 underwent an increase in their specific areas of approximately 45%. Pillared samples treated with 4molL-1 of HCl at 80°C underwent the lowest percent increase in surface area, approximately 10%, compared to the untreated samples. All samples possessed greater uniformity in pore size. Acid treatment prior to pillaring promoted an increase in the number of acid sites of moderate strength compared to pillared natural clay. © 2013 Elsevier B.V. Source


Sahu N.,Kyoto University | Behera S.K.,Japan Agency for Marine - Earth Science and Technology | Ratnam J.V.,Japan Agency for Marine - Earth Science and Technology | Da Silva R.V.,Federal University of Fronteira sul | And 5 more authors.
Climate Dynamics | Year: 2014

Extremely-low discharge events of the Paranaíba River basin during the austral summer season (December-February, DJF), are found to be associated with the Pacific sea surface temperature anomalies resembling the recently identified El Niño Modoki phenomenon. Extreme discharge events are identified based on their persistent flow for 7 days and more after taking retention time into consideration. Ninety percent of the extremely low discharge events during peak streamflow seasons of DJF, are found to occur during the El Niño Modoki years. A diagnostics study of atmospheric anomalies has shown a clear connection between the modified Walker circulation, associated with the El Niño Modoki, and the precipitation anomalies over the Paranaíba River basin. The climate variations have direct relationship with the rainfall. Streamflow variations are considered as the surrogates to rainfalls. Thus, El Niño Modoki phase is important component to understand and predict the streamflow variations in the Paranaíba River basin. © 2013 Springer-Verlag Berlin Heidelberg. Source


Bevilacqua F.,Federal University of Fronteira sul | Backlund P.,University of Skovde | Engstrom H.,University of Skovde
VS-Games 2015 - 7th International Conference on Games and Virtual Worlds for Serious Applications | Year: 2015

The process of monitoring user emotions in serious games or human-computer interaction is usually obtrusive. The work-flow is typically based on sensors that are physically attached to the user. Sometimes those sensors completely disturb the user experience, such as finger sensors that prevent the use of keyboard/mouse. This short paper presents techniques used to remotely measure different signals produced by a person, e.g. heart rate, through the use of a camera and computer vision techniques. The analysis of a combination of such signals (multimodal input) can be used in a variety of applications such as emotion assessment and measurement of cognitive stress. We present a research proposal for measurement of player's stress level based on a non-contact analysis of multimodal user inputs. Our main contribution is a survey of commonly used methods to remotely measure user input signals related to stress assessment. © 2015 IEEE. Source


Lima-Filho A.C.,Federal University of Paraiba | Gomes R.D.,Federal University of Campina Grande | Adissi M.O.,Federal University of Paraiba | Da Silva T.A.B.,Federal University of Paraiba | And 2 more authors.
IEEE/ASME Transactions on Mechatronics | Year: 2012

The system proposed in this paper aims at monitoring the torque and efficiency in induction motors in real time by employing wireless sensor networks (WSNs). An embedded system is employed for acquiring electrical signals from the motor in a noninvasive manner, and then performing local processing for torque and efficiency estimation. The values calculated by the embedded system are transmitted to a monitoring unit through an IEEE 802.15.4-based WSN. At the base unit, various motors can be monitored in real time. An experimental study was conducted for observing the relationship between the WSN performance and the spectral occupancy at the operating environment. This study demonstrated that the use of intelligent nodes, with local processing capability, is essential for this type of application. The embedded system was deployed on a workbench, and studies were conducted to analyze torque and system efficiency. © 2012 IEEE. Source

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