Search

This paper aimed to design an autonomous indirect solar dryer, which can dehydrate the aguaymanto in a costeffective manner, yielding a quality product suitable for export from the central part highland of Peru. To complete this task, it was proposed to design a prototype of autonomous solar dryer of 100 kg per batch of aguaymanto, equipped with flat reflectors and forced air feed, and powered with photovoltaic energy. This system allows to dry aguaymanto fruit at the requirements needed for its exportation. The fryer has the following dimensions: inner dimensions of the drying chamber: bottom 0.60 m, width 1.40 m, and height 1.10 m, with additional 0.05 m for insulation. Hence, the outer measures are bottom 0.70 m, width 1.50 m, and height 1.20 m. Two solar collectors are proposed with the dimensions of each: 1.50 m wide, 2.40 m long, and 0.15 m height; 2 flat mirror reflectors are required. A 80 Wp photovoltaic panel was selected for the forced air system and process control. This solar dryer is expected to cope with the problem of post-harvest deterioration. Also, it will facilitate the export by improving product quality and providing a cost-effective technology.

This paper appraises the accuracy of methods for calculating wind power density (WPD), by comparing measurement values to the shape and scale parameters of the Weibull distribution (WD). For the estimation of WD parameters, the Graphical method (GP), Empirical method of Justus (EMJ), Empirical method of Lysen (EML), Energy pattern factor method (EPF), and Maximum likelihood method (ML) are used. The accuracy of each method was evaluated via multiple metrics: Mean absolute bias error (MABE), Mean absolute percentage error (MAPE), Root mean square error (RMSE), Relative root mean square error (RRMSE), Correlation coefficient (R), and Index of agreement (IA). The study’s objective is to select the most suitable methods to evaluate the WD parameters (k and c) for calculating WDP in four meteorological stations located in Junin-Peru: Comas, Huasahuasi, Junin, and Yantac. According to the statistical index results, the ML, EMJ, and EML methods are the most accurate for each station, however, it is important to note that the methods do not perform equally well in all stations, presumably the graphical conditions and external factors play a major role.

This work deals with the stability of the dynamics of human gait. This is a common exercise. The focus of this investigation is to analyze the knee angle time series and calculate the divergence for over-ground and treadmill walking. Experiments using motion capture technology are used to capture the movement. MATLAB software package is used to calculate the Lyapunov Exponents from the time series. Results are compared with similar studies in the literature. This work provides an insight on the level of stability for treadmill walking. A comparison with stability of normal gait might give an insight on how the treadmill can facilitate rehabilitation using gait.

Resumen La evaluación de nuevas tecnologías en el sistema eléctrico es pertinente para la planificación y operación de la red eléctrica, esto permite brindar un servicio eléctrico de calidad a los usuarios finales y preservar la operación del sistema eléctrico. La presente investigación analiza la integración de los vehículos eléctricos híbridos enchufables (VEHE) en la red eléctrica de distribución, el sistema eléctrico Europeo de Baja Tensión de 906 barras del IEEE es usado como sistema de prueba, considerando el incremento de la demanda eléctrica en función de la operación, horario de carga, tecnología y autonomía de esta nueva tecnología de movilidad. A través de una metodología analítico-no experimental, los siguientes factores fueron analizados: variación de tensión, pérdidas de energía eléctrica e incremento de la demanda en el mediano y largo plazo. Los resultados obtenidos muestran que para niveles de irrupción de esta nueva tecnología es necesario repotenciar la red eléctrica actual para preservar las condiciones de operación estables del sistema eléctrico y cumplir con la normativa del sector eléctrico, los resultados muestran que la conexión masiva y sin control tiene una gran repercusión en la operación de la red eléctrica. Abstract The evaluation of new technologies in the electrical system is relevant for the planning and operation of the electrical network, this allows to provide a quality electrical service to the final users and to preserve the operation of the electrical system. The present research analyzes the integration of plug-in hybrid electric vehicles (EVs) in the electric distribution network. The European low voltage 906 busbar electric system of the IEEE is used as a test system, considering the increase of the electric demand depending on the operation, charging time, technology and autonomy of this new mobility technology. Through an analytical-non-experimental methodology, the following factors were analyzed: voltage variation, electrical energy losses and increase in demand in the medium and long term. The results obtained show that for levels of irruption of this new technology it is necessary to repower the current electrical network to preserve the stable operating conditions of the electrical system and to comply with the regulations of the electrical sector, the results show that the massive and uncontrolled connection has a great impact on the operation of the electrical network.

The scientific literature presents different methods to estimate the parameters of the single diode model of a photovoltaic module, each methodology performs the correction of the parameters for different irradiance and temperature conditions. The present research presents a methodology to determine the IV curves for different irradiance and cell temperature levels, parameters such as series resistance, parallel resistance, and diode ideality factor are estimated for different irradiance and temperature conditions. Through a comparative analysis and the use of statistical indicators, it was determined that the proposed methodology is more accurate than the existing methodologies for estimating the single diode model of a photovoltaic panel and the determination of the I-V curves.

This work deals with the stability of the dynamics of human squat exercise. This is a common exercise. The focus of this investigation is to analyze the knee angle time series and calculate the divergence for different weight added in the exercise. Experiments are conducted and motion capture used for each of the cases. Then the Lyapunov exponents of the time series of the knee joint angle are determined. Matlab software package is used for all calculations. Results are compared with data available in the literature. This work provides insight on the level of stability for added weight on the human squat exercise. This gives an insight on the level of safety of this exercise as weight is added to the human subject.

The main focus of this work is to investigate the effect of weight on the stability of human squat exercise. The squat exercise is a common daily activity. Experiments are conducted using one human subject. A VICON motion analysis system integrated with Force Plates is utilized for these experiments. An experimental protocol is developed and followed. This work analyzes the time series of the normal component of the ground reaction forces and each coordinate of the center of pressure. These time series are used to estimate the Lyapunov Exponents using Rosenstein method. MATLAB software package is used for this investigation. The results of this work are compared with results from literature. Present work gives more information relating the safety of the squat exercise when adding additional weight. One can see that the effect of additional weight on stability depends on its value. In the cases of small and moderate additional weight the stability is the same or increases, while for the largest additional weight the investigated stability decreases.

The current study quantifies and characterizes the types of the Natural Plant Coverage (NPC)within the Eloy Alfaro canton and its degrees of alteration by anthropic action. The methodology is based on the interdependent interpretation of products from remote sensors, with the support of the geographic information systems. The Eloy Alfaro canton, which is part of Colombian Choco Corridor, covers a total area of 466,285.81 ha, of which 55.791% (260,146.72 ha)corresponds to the NPC, which comprises forests, shrubs, and moist herbaceous and wetland, highlighting the slightly altered rainforest with 46.141% (215,148.43 ha), followed by moderately altered rainforest with 3.761% of the total cantonal surface (17536.75 ha). The Ecological Reserves Cotacachi-Cayapas and Cayapas-Mataje as well as the Pambilar Wildlife Refuge, which are part of the Governmental Natural areas Heritage (PANE), occupy a total of 147,486.78 has corresponding to 31.630% of the canton surface. The complete surface area of the Eloy Alfaro canton has been characterized and evaluated for its present alteration by the multiple anthropic activities, allowing a general view of the given circumstances of the actual stage of the NPC. Such detailed evaluation and diagnostic mapping are a key tools for any plan of prevention of further potential alteration of the NPC.

This paper deals with the effect of obesity on human squat exercise. The aforementioned clinical condition affects gait (and other daily common activities) in a sense that alterations are made to gait patterns and speed in order to accommodate the patient when participating in physical activities such as walking, making a turn, etc. This work consists of experimental data collected from a subject during moderate squat exercise. Two cases were considered, first, subject with no additional mass, and second, subject with additional mass. The experimental data is collected in the Biomechanics Laboratory at the University of Texas Rio Grande Valley. The squat depth for each trial was kept at a constant height 1 foot from the ground, which corresponds to moderate squat exercise. Phase planes, tools used in nonlinear dynamics, were used to investigate the significant differences between the two cases, no additional weight vs. additional weight. Also, Lyapunov exponents are calculated to assess the stability of the knee joint. There are significant differences in the lateral direction of the centers of mass of both femur and tibia. Moreover the stability of the knee flexion angle decreases with additional mass.

The modular multi-level converter is an emerging technology for high-voltage applications, renewable energy and motor drive. By using the model-based design, the embedded software is designed step by step, main interest are software-in-the-loop and processor-in-the-loop approaches. The converter modelling and control have been thoroughly investigated in the literature, a verification of the controllers according with both approaches are presented in this paper. The submodule-level averaged model is used in a 150 MW grid connected converter. Test numerical equivalence is developed in host platform for the software-in-the-loop stage. Processor-in-the-loop stage by behaviour test of the code generated is tested, the simulation is developed in the Texas Instruments F28335 Delfino MCU processor. It is concluded that the presented control strategies in-the-loop simulations are closed to the model simulated in Matlab/Simulink, this verification is a valuable results for the next implementation in real-time simulation.

This paper compares the capacitor voltage in the Arm Level Averaged (ALA) model of Modular Multi-Level Converter (MMC) with estimated value using the Kalman Filter (KF). The evaluation considers different cases and the influence of model parameters in the estimated state according to Kalman Gain (KG) and Estimated Error Covariance (EEC). The analysis relates the estimate and measured voltages, they have similar peak values and wave shape according with all evaluated cases, so the capacitor voltage estimation can be used in voltage control arm-balancing strategy to decrease the number of sensors and simplify the control system, especially in large MMC projects with hundreds of submodules (SM).

The education system in general in Peru is changing, aligned with the Ministry Education's policies. In this context, this paper proposes aspects to improve the teaching of engineering, aims to develop competencies in students aligned with the policies of strategic sectors, through mechanisms that support the update of the study plan. These aspects will be developed jointly with the existing teaching through: teaching current issues, company-university chairs and continuing education programs.

The theoretical and practical aspects are complemented in the university teaching, the experimental phase is required to understand abstract concepts such as electrical engineering. This paper presents the proposal of improvement for the structure of laboratory practices in phases: preliminary activities, experimental and final activities. Also intends with this work, provide aspects as structure a report and introduction to the use of simulation software in electric engineering.

The modular multilevel converter (MMC) in high voltage direct current (HVDC) is equipped with hundreds of sub-modules (SMs), so the detailed model consist of hundreds of switching devices and consequently large computational effort but mathematical converter model with Arm Level Averaged (ALA) allows to know the dynamic and converter control decreasing simulation time. This paper presents a control strategy decou- pling the modulation index implemented in MMC-ALA model, it allows MMC operation with variable DC bus voltage but keeping constant the capacitor voltage in upper and lower arms, the evaluations consider the next operations: boost mode reducing DC bus voltage to 0.5.p.u., DC fault and SM voltage increased. The upper and lower capacitor voltages in all cases follow the reference independently to DC bus voltage value, the strategy is simulated in 150 MW converter using Matlab/Simulink.

In May 2009, as the H1N1 swine flu outbreak was in the early stages, a conference was held at the New York Academy of Sciences to discuss what was known about the virus and what was being done to stop the outbreak. In May 2010, a follow-up conference was again held at the New York Academy of Sciences, but now to discuss the H1N1 outbreak retrospectively. The report presented here summarizes the 2010 conference proceedings.