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One of the main challenges for river-based hydrokinetic power plant development is the difficulty in estimating system energy potential and economic viability. The present study proposes and applies a methodology to estimate hydrokinetic potential of two rivers located in the Amazon River basin. The methodology is based on numerical simulations of rivers using ANSYS CFX software with the aid of experimental data such as bathymetry, along with data collected in flow measurement campaigns to study maximum velocity points and turbine configuration planning within regions of the rivers' cross-sections. Based on these analyses, factors such as the number of turbines, energy potential and economic viability (considering uncertainties) could be estimated. The power generated in the studied power plants was 109.5 and 31.5 Kw, while the levelized cost of electricity varied between 80 and 125 USD/MWh. These values were generally noncompetitive compared to other renewable sources in Brazil. The inclusion of hydrokinetic energy production in the distributed generation market and the use of this technology in isolated Amazonian communities can increase economic viability. • CFD tools were applied to estimate hydrokinetic potential in two Brazilian rivers. • Proposed methodology was validated using flow measurements in the rivers. • Applied methodology allows studying maximum velocities and turbine arrangement. • Estimated electrical power in both rivers were equal to 109.5 and 31.5 kW. • Levelized electricity costs varied between 80 and 125 USD/MWh in the studied rivers. [ABSTRACT FROM AUTHOR]

Francisella noatunensis subsp. orientalis (Fno) is the causative agent of piscine francisellosis in warm water fish including tilapia. The disease induces chronic granulomatous inflammation with high morbidity and can result in high mortality. Early and accurate detection of Fno is crucial to set appropriate outbreak control measures in tilapia farms. Laboratory detection of Fno mainly depends on bacterial culture and molecular techniques. Recombinase polymerase amplification (RPA) is a novel isothermal technology that has been widely used for the molecular diagnosis of various infectious diseases. In this study, a recombinase polymerase amplification (RPA) assay for rapid detection of Fno was developed and validated. The RPA reaction was performed at a constant temperature of 42°C for 20 min. The RPA assay was performed using a quantitative plasmid standard containing a unique Fno gene sequence. Validation of the assay was performed not only by using DNA from Fno, closely related Francisella species and other common bacterial pathogens in tilapia farms, but also by screening 78 Nile tilapia and 5 water samples. All results were compared with those obtained by previously established real-time qPCR. The developed RPA showed high specificity in detection of Fno with no cross-detection of either the closely related Francisella spp. or the other tested bacteria. The Fno-RPA performance was highly comparable to the published qPCR with detection limits at 15 and 11 DNA molecules detected, respectively. The RPA gave quicker results in approximately 6 min in contrast to the qPCR that needed about 90 min to reach the same detection limit, taking only 2.7–3 min to determine Fno in clinical samples. Moreover, RPA was more tolerant to reaction inhibitors than qPCR when tested with field samples. The fast reaction, simplicity, cost-effectiveness, sensitivity and specificity make the RPA an attractive diagnostic tool that will contribute to controlling the infection through prompt on-site detection of Fno. [ABSTRACT FROM AUTHOR]

Hydrokinetic energy generation is a renewable source that captures kinetic energy from river or tidal currents. Little physical construction is required, and environmental impacts are reduced. The identification of potential projects and definition of turbine arrangement to consider the wake dissipation generated by the flow on the rotor are two extremely important points for successful implantation of hydrokinetic farms. The present study presents a methodology for evaluating the length of the hydrokinetic rotor wakes in natural channels through the use of computational fluid dynamics techniques and the actuator disk model. These techniques were applied in this study on a portion of the Brazilian Amazon river with real measured data on velocity, curvature and geometry in the field. The wake length obtained was between 7 and 9 diameters, varying according to the operation point of the turbine. A study of the hydrokinetic arrangement for the three turbines was also carried out and an electrical power of 18.3 kW was obtained. The outcome and results of the study provided insight on hydrokinetic turbine wakes in rivers which may aid in the development of future studies, thus resulting in a greater diffusion of hydrokinetic power plants. [Display omitted] • We studied wake of hydrokinetic turbines in an Amazonian river through CFD tools. • Hydrokinetic turbine was modelled in CFD using BEM theory and actuator disc model. • Wake length was analyzed in three scenarios of turbine power coefficient. • We studied the energy potential in the river for an arrangement with three turbines. [ABSTRACT FROM AUTHOR]

The CFD simulations for external flow problems can request high computational costs. To reduce these costs, viscous/inviscid interaction methodology based in the domains decomposition and the Helmholtz velocity decomposition has been developed. The calculation of viscous flow by the Navier–Stokes equations is made on a computational reduced domain. In this work, an interactive methodology is presented, which consists of: calculate the potential flow outside the rotational region, impose the potential flow velocity field as a boundary condition in the reduced domain boundary, calculate the transpiration velocity to correct the potential flow, recalculate the potential flow velocity field outside the rotational region, and update the boundary conditions on the reduced domain. To formulate the transpiration velocity, the velocity decomposition approach was used, but to calculate the transpiration, it is necessary determine the boundary of the rotational region, called rotational boundary, where the vorticity is negligible. For this, negligible vorticity criteria were developed to find that boundary; however, determining it can be a complex task, as is the case of flow around multiple bodies. Some techniques, which may include the use of an auxiliary surface, have been developed to facilitate the determination of the rotational boundary. Thus, two proposals were made in this work, first: the use of an auxiliary surface to determine the rotational boundary to multiple bodies cases; and second: a new negligible vorticity criterion based on the total pressure field. Calculations were performed in the viscous reduced domain for two-dimensional incompressible flow, around a single body and multiple bodies. The use of the present methodology allowed reducing the computational costs. The aerodynamic coefficients and viscous flow fields obtained in the reduced domain were satisfactory for such engineering problems. [ABSTRACT FROM AUTHOR]

Viscous/inviscid interaction methods employing velocity decomposition have been explored for reducing computational costs in external flow problems. For this, viscous simulations are made in reduced computational domains encompassing the rotational flow region. The coupling of potential and viscous solutions is made on a boundary of negligible vorticity, assessed by means of sampling lines normal to the body wall and the wake. For bluff bodies, sampling lines at the rear tend to be submerged in rotational regions, making it difficult to build the coupling boundary. For overcoming this difficulty, it is proposed in this work to use a transpiration auxiliary surface to represent the influence of the body and the wake. The null vorticity criterion for finding the coupling boundary is also proposed. The proposals are tested for laminar flows around a square, a circular cylinder and a semi-ellipse. The obtained results are compared with those for extended domains. The velocity decomposition with an auxiliary surface is able to reproduce with satisfactory accuracy the flow fields in the reduced domain as well as the drag coefficient on the bodies. [ABSTRACT FROM AUTHOR]

Teaching is an activity that requires understanding the class's reaction to evaluate the teaching methodology effectiveness. This operation can be easy to achieve in small classrooms, while it may be challenging to do in classes of 50 or more students. This paper proposes a novel Internet of Things (IoT) system to aid teachers in their work based on the redundant use of non-invasive techniques such as facial expression recognition and physiological data analysis. Facial expression recognition is performed using a Convolutional Neural Network (CNN), while physiological data are obtained via Photoplethysmography (PPG). By recurring to Russel's model, we grouped the most important Ekman's facial expressions recognized by CNN into active and passive. Then, operations such as thresholding and windowing were performed to make it possible to compare and analyze the results from both sources. Using a window size of 100 samples, both sources have detected a level of attention of about 55.5% for the in-presence lectures tests. By comparing results coming from in-presence and pre-recorded remote lectures, it is possible to note that, thanks to validation with physiological data, facial expressions alone seem useful in determining students' level of attention for in-presence lectures. [ABSTRACT FROM AUTHOR]

Capturing wave power from the ocean is a renewable energy form which complements and diversifies energy grid sources. With its extensive coastline, Brazil has great potential for wave power generation. Economic viability is a key factor for energy generation projects, so the aim of this study is to conduct an economic assessment and Levelized Cost of Energy (LCOE) involved in implementation of wave energy converter devices to generate electricity in Brazil, given the various uncertainties associated with the parameters involved. To this end, the study was divided into two stages: an energy and economic analysis was carried out to implement wave energy converters in three regions of Brazil with two different converter devices; then, the levelized costs of electricity generation were calculated, given the multiple parameter variations involved, in order to observe the possible oscillations of these costs and the parameters responsible for the greatest impact. The results show that a high capacity factor has the best influence on LCOE values, making the ocean wave energy sales rate comparable with photovoltaic solar energy in Brazil. The study highlights the importance of investment in technology and development for ocean wave energy in order to see greater gains, thus making this type of project generation in Brazil greater possibility. [ABSTRACT FROM AUTHOR]

• FIR filter designed with game theory is implemented. • Provides a pathway for a trans receiving data with minimum space required. • Extraordinary results for compression of ultrasound and MRI images are achieved. In image processing, there are many inventions results in processing the images effectively suitable for applications like change detection, SAR image analysis, Television i.e. for compressing videos for effective transmission etc. In Social network, exchange of bulk information needs an effective compression technique to compress, transmit, decompress and reconstruct the original quality of source information. Compression technique can reduce the storage deficiency, energy consumption. In this proposed methodology, an effective Finite Impulse Response filter designed with meta-heuristic techniques-a game theory-based approach provides a compromising data compression ratio for standard input images. Effective quality indicators such as compression ratio, Mean Square Error stands as proof for the implications of the anticipated technique in medical applications as it affords extraordinary results for compression of Ultrasound and MRI images, thus providing a pathway for a trans receiving data with minimum space required. [ABSTRACT FROM AUTHOR]

One of the main hydrodynamic phenomena in hydrokinetic turbine operation is the formation of a spiral movement after the flow passes through the rotor, which is known as the wake. Understanding these wakes is fundamental for arranging the distribution of turbines in a hydrokinetic energy project. In this context, this study has two purposes: i) to review studies involving hydrokinetic turbines wakes, obtaining data on wake dissipation length; and ii) evaluate the possibility of elaborating an equation to estimate wake dissipation length using the collected data. In order to propose the equation, the wake dissipation length was related to the turbine velocity and diameter using deviation minimization methods. The literature surveys revealed the scarcity of experimental studies on river hydrokinetic turbine wakes. Additionally, the dissipation lengths obtained in the considered investigations vary greatly, thus indicating the influence of numerous factors over this phenomenon. The correlation results serve as an introduction to this theme and as a basis for future developments. • Studies involving hydrokinetic turbine wake length were reviewed. • A second row of turbines can reduce the distance for new turbines insertion. • The use of turbines at the maximum efficiency point reduces the wake length. • Correlations between wake lenght and influencing factors were evaluated. [ABSTRACT FROM AUTHOR]