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The growth in the demand for electricity has led to the development and application of technologies that make its means of transport more efficient. Thus, one of these options is the implementation of transmission lines in HVDC. One of important design parameters of these lines is to know their magnetic field distribution, when it is required to calculate it, there is no methodology that can be applied to HVDC transmission lines. The following article presents a methodology that allows obtaining the density of the magnetic field on the corridor of an overhead transmission line. A case study of a 500 kV bipolar line in HVDC is presented, the results obtained are compared using the commercial software Field and corona Effects (FACE), the results obtained are consistent with those obtained from the presented methodology. An analysis of the impact of the transmission line configuration on the magnetic field density is developed, defining the most efficient configuration.

Periodic superlattices constitute ideal structures to modulate the transport properties of two-dimensional materials. In this paper, we show that the tunneling magnetoresistance (TMR) in phosphorene can be tuned effectively through periodic magnetic modulation. Deltaic magnetic barriers are arranged periodically along the phosphorene armchair direction in parallel (PM) and anti-parallel magnetization (AM) fashion. The theoretical treatment is based on a low-energy effective Hamiltonian, the transfer matrix method and the Landauer–Büttiker formalism. We find that the periodic modulation gives rise to oscillating transport characteristics for both PM and AM configurations. More importantly, by adjusting the electrostatic potential appropriately we find Fermi energy regions for which the AM conductance is reduced significantly while the PM conductance keeps considerable values, resulting in an effective TMR that increases with the magnetic field strength. These findings could be useful in the design of magnetoresistive devices based on magnetic phosphorene superlattices.

The effect of the galvanic corrosion process taking place between aluminium alloy (AA2024-T3) and carbon fiber reinforced plastic (CFRP) immersed in 0.05 M NaCl was studied using organic and inorganic compounds as corrosion inhibitors. Electrochemical approaches such as electrochemical noise analysis (ENA) and electrochemical impedance spectroscopy (EIS) were carried out to evaluate efficiencies of 1,2,4-triazole (C2H3N3) and cerium nitrate hexahydrate (Ce(NO3)3·6H2O) as corrosion inhibitors. The highest efficiency was reached for Ce(NO3)3.6H2O, with some improvement observed by adding C2H3N3 in a mixed inhibitor solution. The noise resistance (Rn) and polarization resistance (Rp) values calculated from ENA and EIS data showed almost identical behavior with different magni­tudes but similar trends. Adsorption isotherm models estimated with fractional surface coverage (q) parameter were fitted better to Langmuir model for C2H3N3 and Temkin model for Ce(NO3)3·6H2O. The calculated values of Gibbs free energy suggested physi­sorption and chemisorption as spontaneous interactions between a metal surface and both inhibitors. Energy-dispersive X-ray spectroscopy (EDS) was carried out before and after immersing AA2024-T3 in the electrolyte, identifying rich zones in copper with cerium deposited over it and confirming the presence of rare-earth oxide deposition and oxide film products. The EDS analysis for CFRP revealed the deposition of Ce and Al particles over its surface after immersion in the electrolyte, especially in the areas rich in carbon.

This article provides an analysis of harmonics existing in the electrical installation at the plant “Chiconautla”, dependent on the General Management Department of Construction and Hydraulic Operation of Mexico State (DGCOH). For electrical power quality studies, monitoring equipment was initially installed at the Point of common coupling, to obtain the maximum average values of the total distortion harmonics of voltage and current. This monitoring is important, due to these signals must meet the standards established by regulatory organizations, to improve the energy quality, reduce costs and to avoid electric equipment’s failures. It can be determined that the main contributions to these distortions are third, fifth and seventh harmonics. The time of transfer given by the automatic transfer equipment, was measured when failures in the network occurred. It can be said that all measurement satisfies the requirements of network code. Some recommendations are given to improve the performance of the system.

In this paper, simulated and experimental analysis of an accelerometer with beams based on arrangements of segments of different width is performed. A comparison with an accelerometer of uniform beams is carried out. Micro accelerometers were scaled to obtain millimeter lengths to obtain low cost prototypes and the possibility to test them, also using an experimental set-up of low cost. The simulation tool employed is Ansys. For experimental validation, additive manufacture using PLA, a type of thermoplastic polymer, is considered. The parameter under analysis is the displacement the proof mass of accelerometers. The larger displacement was obtained for the case of symmetrical beams, with a thinner width equals to 1/3 of width the uniform beam, but a decrease in the natural frequency of the system was also obtained.

In this paper, we propose a two-lane cellular automata model that explains the relationship between traffic-related parameters and likelihood of accidents P a c at a signalized intersection. It is found that, the risk of collision rises as well as the lane-changing probability P c h g augments, besides, the accidents and inflow α show a nonlinear relationship. Moreover, P a c exhibits three different phases (I, II and III) depending on α . Likewise, the system exhibits a second (first) order transition from phase I to phase II when P c h g >0 ( P c h g = 0 ). Nevertheless, the transition from phase II to phase III is of first (second) order when P c h g > 0 ( P c h g = 0 ). In addition, the result analysis shows that the distribution of accidents according to the intersection sites is not equiprobable. Furthermore, when the traffic arriving strength is not very high, the green light length of one road should be increased to restrain P a c and enhance the road safety. Finally, the model results illustrated that the traffic at the intersection is more dangerous adopting asymmetric lane-changing rules than symmetric ones.

The electronic structure and the transport phenomena of δ-MIGFETs have been studied in an AlxGa1−xAs host matrix. The subband structure and mobility calculations were performed within the effective mass approximation and relative mobility formula, respectively. Both the electronic structure and the transport properties are calculated as dependent on the applied magnetic field (B), the aluminum molar fraction (x) and the contact voltage in one of the gates (VC1). It was found that the mobility and conductivity are enhanced by increasing the magnetic field for appropriate aluminum molar fraction and contact voltage. In particular, the mobility (conductivity) is improved almost 26% (32%) for VC1 = 900 meV (850 meV), x = 0.2, and B = 20 T.

This paper presents the design and implementation of a system to monitor the energy quality using ATmega2560 microcontroller embedded in the Arduino MEGA board. The proposed system is capable of acquiring voltage and current signals at sampling rate of up to 22 kHz simultaneously, and through digital processing obtains the basic parameters of the electrical signal. The samples obtained are possible to send, at various transmission rates, through the USB port to the computer. The components used in the realization are of low cost compared with the existing equipment at commercial level. The reliability of the system is validated by comparing the results with electrical metrology equipment. Keywords-- Real-time Monitoring, Open Source microcontroller, Basic electrical parameters measurements

Ballistic electron transport in a silicene structure, composed of a pair of magnetic gates, in the ferromagnetic and an-tiferromagnetic configuration is studied. This theoretical study has been done using the matrix transfer method to calculate the transmission, the conductance for parallel and antiparallel magnetic alignment and the magnetoresistance. Results show that conductance and magnetoresistance oscillate as a function of the length between the two magnetic domains. The forbidden transmission region also increases as a function of the barrier separation distance.

En este artículo se analiza una red de distribución urbana de 23 kV típica de la zona central de México. El objetivo es determinar la distancia máxima de separación entre apartarrayos de línea que permita reducir las salidas de los circuitos de distribución por descargas atmosféricas directas e indirectas. Con base en las características eléctricas, ambientales, ceráunicas y geográficas de la zona, niveles de cortocircuito y las sobretensiones provocadas por maniobras rutinarias, se selecciona el apartarrayos siempre con el principal objetivo de determinar su espaciamiento adecuado sobre la línea para que éste funcione apropiadamente. La investigación se lleva a cabo con la ayuda del software llamado Alternative Transients Program (ATP) donde se realiza el cálculo de los parámetros de la línea utilizando el modelo de K.C. Lee, las sobretensiones transitorias por onda viajera y por conexión de capacitores también son simuladas. La motivación de este trabajo consiste principalmente en contar con un mayor sustento teórico y técnico (actualmente escueto) para determinar el espaciamiento entre apartarrayos de la red de distribución considerada y así aumentar la calidad del suministro eléctrico de la zona.

In this paper, a low cost, stand-alone and configurable data acquisition system with wireless communication to remote host is presented. The system allows recording up to eight multiplexed analog signals, with 12-bits resolution in variable ranges and a maximum sampling rate 11,500 S/s for each channel. The realization of the systems was done using FPGA as the main chip, and control multi-channel ADC chip to collect data. The data are transmitted to the host using wireless connectivity technologies Bluetooth or XBee, these data can be displayed and analyzed by computer application. The channels, sampling frequency and transmission rate can be configured by the user.

It is very important for the car users to have several communication systems and many antennas, which respond to the demands of aesthetics and efficiency. In this case, it is necessary to consider different types of materials and geometries. Among the automobile systems, the navigation systems are found, which are formed by a Global Position System (GPS), with a pre-charged base of maps and highways in order to locate the vehicle. For the reception of the GPS signals, circularly polarized patch antennas are used, which must be designed to operate at 1.57 GHz. This work is focused on the analysis of a circular antenna performance, designed for GPS, by means of the simulation of the following cases: antenna without radome, antenna with acrylic radome, and, finally, antenna on the roof of an automobile, considering the effect of the complete chassis. A Basic, a Simplified and a More Simplified Advanced Car Models (BCM, SACM, and MSACM) were used in order to analyze the chassis shape. The simulations were carried out with the software FEKO. The fabrication and experimental and practical tests are also presented.

Various feedback strategies are proposed to improve the traffic flow. However, most of these works did not take road safety into consideration. In this paper, we studied the impact of four feedback strategies on the probability of rear-end collisions ([Formula: see text]). We proposed a new feedback strategy named Accidents Coefficient Feedback Strategy (ACFS) in which dynamic information can be generated and displayed on a board at the entrance of two-route scenario with intersection to help drivers to choose the appropriate road. This new strategy can greatly improve road safety and make the flow smooth as possible at the same time. Moreover, the impact of the intersection and boundary rates ([Formula: see text] and [Formula: see text]) on [Formula: see text] is also studied.

Using the Nagel-Schreckenberg model, we investigate the flow characteristics in a traffic circle system, where the entry lanes are controlled by traffic lights operating in a fixed-time ([Formula: see text]. We considered four different strategies to control traffic coming from [Formula: see text] entry lanes. We found that depending on the strategy used, four distinct traffic phases can appear in the circulating lane of the traffic circle, namely free flow, congestion, maximum current, and gridlock. Also, we investigate the origin of the gridlock phase in both cases (i.e. with/without traffic lights). Furthermore, the lengths of queues of stopped vehicles in the entry lanes were studied. We found that the traffic flow behavior on the exit/entry lanes depends strongly on the flow characteristics at the circulating lane as well as traffic lights strategy. To improve the operation of the traffic circle system, we have studied the time delay between the traffic lights to switch where all entry lanes go red, which allowing vehicles to clear the circulating lane.

In this paper, we propose a stochastic cellular automata model to study the traffic behavior at a single-lane roundabout. Vehicles can enter the interior lane or exit from it via [Formula: see text] intersecting lane, the boundary conditions are stochastic. The traffic is controlled by a self-organized scheme. It has turned out that depending on the rules of insertion to the roundabout, five distinct traffic phases can appear, namely, free flow, congestion, maximum current, jammed and gridlock. The transition between the free flow and the gridlock is forbidden. The density profiles are used to study the traffic pattern at the interior lane of the roundabout. In order to quantify the interactions between vehicles in the interior lane of the roundabout, the velocity correlation coefficient (VCC) is also studied. Besides, the spatiotemporal diagrams corresponding to the entry/exit lanes are derived numerically. Furthermore, we have investigated the effect of displaying signal ([Formula: see text], as the [Formula: see text] decreases, the maximum current increases at the expense of the free flow and the jamming phase. Finally, we have investigated the effect of the braking probability [Formula: see text] on the interior lane of the roundabout. We have found that the increase of [Formula: see text] raises the spontaneous jam formation on the ring. Thus, enlarges the maximum current and the jamming phase while the free flow phase decreases.

For illumination sources designers is important to know the illumination distribution of their products. They can use several viewers of IES files (standard file format determined by Illuminating Engineering Society). This files are necessary not only know the distribution of illumination, but also to plain the construction of buildings by means of specialized softwares, such as Autodesk Revit. In this paper, a complete portable system for luminaries’ characterization is given. The components of the systems are: Irradiance profile meter, which can generate photometry of luminaries of small sizes which covers indoor illumination requirements and luminaries for general areas. One of the meter´s attributes is given by the color sensor implemented, which allows knowing the color temperature of luminary under analysis. The Graphic Unit Interface (GUI) has several characteristics: It can control the meter, acquires the data obtained by the sensor and graphs them in 2D under Cartesian and polar formats or 3D, in Cartesian format. The graph can be exported to png, jpg, or bmp formats, if necessary. These remarkable characteristics differentiate this GUI. This proposal can be considered as a viable option for enterprises of illumination design and manufacturing, due to the relatively low investment level and considering the complete illumination characterization provided.

The combined effects of hydrostatic pressure and voltage contact on subband structure and optical transitions in GaAs delta-MIGFET (Delta-Multiple Independent Gate Field Effect Transistor) have been theoretically studied. Results obtained show the optical absorption is quite sensitive to the applied hydrostatic pressure and contact voltage. These can be suitable for good optical performance and various infrared optical device applications and can be easily obtained by tuning the voltage contact and hydrostatic pressure strength.

The semi-spherical meter uses a photo-detector mounted on a mobile rectangular arc, which by means of two stepper motors describes the semi-spherical trajectories required. For controlling motors and data acquisition, a Peripheral Interface Controller (PIC) is employed, which helps keeping the low cost of the overall system. One of the stepper motors is located on the lateral axis of the device; that displaces the sensor along a semi-circular trajectory of 170°, almost complete meridians. Another motor located at the base of the device enables 360° rotation of the illumination source under test. The precision is increased by the using of two angle sensors located on the opposite lateral axis and on the mobile base of the illumination source. Additionally, before the data obtained from the photo-detector arrive to the PIC, a stage of signal conditioning is used. This step allows us to increase not only the precision, but also the versatility of the meter to analyze illumination sources of different sizes and fluxes. The communication protocol between the data acquisition stage and the computer is USART. A graphical user interface (GUI) is employed on the base of the hyperterminal. The number of measurement points is determined by programming the two motors. The mechanical structure provides enough rigidity for supporting the accuracy required by the data acquisition circuitry based on a PIC. Measurement of illumination sources of different sizes is possible by using adjustable lengths of the mobile base and the ring.

Esta investigación presenta la simulación de las sobretensiones ocurridas durante una maniobra de mantenimiento en un compensador estático de potencia reactiva de 230 kV. El incorrecto funcionamiento de un interruptor de potencia causa una falla catastrófica que incluye la explosión y el incendio del equipo. La Información obtenida de investigaciones previas, donde se analizan los estados estable y transitorio del compensador, no toma en cuenta la combinación del comportamiento del compensador y la fallida operación de los medios de desconexión. La incorrecta apertura de uno de los polos del interruptor de potencia del compensador provoca sobretensiones interesantes las cuales están relacionadas con las componentes armónicas de tensión y corriente generadas por un elemento clave de la falla: el reactor controlado por tiristores. En este trabajo se utiliza el Software Alternative Transients Program (ATP) para modelar el compensador y obtener el cálculo de las sobretensiones transitorias. Se analizan las frecuencias naturales y el espectro armónico de las señales manejadas por el compensador. Con la ayuda de una videograbación se muestran imágenes reales de los arcos eléctricos generados debido a las sobretensiones. Este estudio se realiza por primera vez en este compensador estático y la información resultante es de mucha utilidad futura para el diseño eléctrico y la planificación de la operación de las redes de potencia.