Alejandro Castañeda-Miranda

• Engineering doctor , Mechatronics and instrumentation specialization
• PostDoc Position at National Autonomous University of Mexico

A novel embedded photoacoustic system design is described and a calculation method is proposed to determine the blood hemoglobin oxygen saturation through the thermal properties of different skin color types. A heat equation model allows a calculation procedure to determine the reflection and transmitted thermal wave amplitude for obtaining a depth...

Resumen Diversos estudios han evaluado el uso de recubrimientos protectores para alargar la vida de herramienta, maquinaría y estructuras metálicas en ambientes ácidos o alcalinos. Con el objetivo de contribuir en esta área, el presente trabajo se enfoca en la síntesis, caracterización y evaluación de pigmentos a base de óxido de hierro (hematita y...

A novel Agro-industrial IoT (AIIoT) technology and architecture for intelligent frost forecasting in greenhouses via hybrid Artificial Intelligence (AI), is reported. The Internet of Things (IoT) allows the objects interconnection on the physical world using sensors and actuators via the Internet. The smart system was designed and implemented throu...

This paper is aimed at continuation of frost intelligent control from the smart farming perspective that is proposed by Castañeda and Castaño (2017) through Internet of things (IoT) and a Weather Station with an Artificial Neural Network (ANN). Moreover, an intelligent anti-frost irrigation management system is presented. The climatological station...

A design and principle of silicon photodiodes (PD) operation in the frequency domain are presented. To further enhance the signal-to-noise ratio, a methodology is proposed regarding how to cut down the response in the frequency domain between the time constant and stability characteristics. An algebraic-analytic model is developed to obtain the fre...

The temperature readings for all the 365 days and the 24 hours may be fitted through a 3 × 3 matrix (the so-called T-matrix). The mean square deviation between this fit and the actual meteorological measurements is smaller than three degrees Celsius. Four entries of this (nonsymmetric) matrix may be fixed by other means, leaving only five independe...

Currently, the automotive industry has made great advances in the incorporation of materials such as carbon fiber in high-performance cars. One of the main problems of these vehicles is warming, which is generated inside due to the heat transfer produced by solar radiation falling on the car, mainly on the roof. This research proposes the preparati...

The traditional method for the estimation of soil loss by croplands erosion is the measurement through erosion pins, which consists of stakes with a specified height distributed across the land area; however, this method is inaccurate to measure the soil depth. In some cases, a simple description of the 3D and depth map scenarios is useful to under...

A fuzzy logic-based embedded system to characterize materials and metamaterials is presented. Trapezoidal and Gaussian profiles, used as membership functions, allow to classify materials despite variations on light intensity. The results on various materials show the capacity of the system to calculate the refractive index as a complex number, thro...

The present work presents the application of intelligent systems for a weather monitoring station, which is an instrument to measure and register various meteorological variables, where the generated data are incorporated in a neural system for the frost prediction from numerical models using the studies records of climatic behavior. In the micro-p...

A Radiometry Photothermal Infrared technique, by using a calibrated scanning depth profile, for biomedical applications is described. The instrument, consists of a pulsed medium-power laser (500 mw), collected and focused onto an infrared detector after impinging on the sample, by using a look-in amplifier, thereby obtaining the amplitude and phase...

Thermal comfort in greenhouses is a key fact to enhance productivity, due to the excess demand of energy for heating, ventilation and agroclimatic conditioning. Frost, in particular, represents a serious technological challenge if the crop sustainability is to be ensured. A Multi-Layer Perceptron artificial neural network, trained by a Levenberg-Ma...

The fluorescent decay of the levels ³H4 and ³F4 of Tm³⁺ in LiYF4 crystals doped with Tb³⁺ and Eu³⁺ was mathematically modeled to estimate the optimal doping levels to maximize the laser emission at 1.5 μm of the transition ³H4 → ³F4. The analysis is carried out both through the solution of the master energy transfer equations that govern the non-ra...

In this paper, a calibrated using a mathematical model for Radiometry Photothermal technique Infrared, considering their use in biomedical applications instrument, experimental technique consists of a medium-power laser, which develops switches by an electro-optical modulator, subsequently incident on the sample, the radiation is collected and focu...

The purpose of the invention is to provide a method for the capture, analysis, inference, animation and virtual modulation of human movements. Another purpose of the invention is that it uses video camera devices, thermal and optic sensors for verifying the virtual modulation and animation of human movements, which enable the monitoring of the stat...

A pc-based automatic system for fingerprints recording and classification is described, based on the vector analysis of bifurcations. The system consists of a six-step process: a) acquisition, b) preprocessing, c) fragmentation, d) representation, e) description, and f) recognition. Details of each stage, along with actual examples of fingerprints...

Subsurface drainage systems are used to control the depth of the water table and to reduce or prevent soil salinity. Water flow in these systems is described by the Boussinesq Equation, and the Advection-Dispersion Equation coupled with the Boussinesq Equation is used to study the solute transport. The objective of this study was to propose a finit...

The invention refers to the method and system for monitoring electric energy with harmonics and inter-harmonics for predicting the faults in low-voltage substations, also including devices for the detection in situ of faults in the substation secondary. With the purpose of detecting incipient faults in electric network installations by electronic d...

There is now an urgent need to consume immediately products in short periods because they can quickly reach the decomposition. The use of solar energy in dehydrated agricultural products is an important element in our days, since through the appropriate use of technology high yields can be achieved in the postharvest products. With the designed and...

This study introduces the development of a user-friendly and quite effective energy monitoring system installed in the building of School Engineering at the Universidad Autonoma de Queretaro since 2008. The metering and control software, that processes and analyzes the digitalized signals, has been developed in Integrated Development Environment (I...

The purpose of the invention is to provide a system for monitoring the behavior of the operation of an underground aquifer distribution installation, the invention comprising an aquifer well and the accessories thereof, such as a hydraulic substation and terminals, and the devices for the early detection of faults using electronic devices coupled t...

The purpose of the invention is to develop a monitoring and inspecting mobile device for supervising and diagnosing fiber optics installed over the guard wire of electric transmission lines, which consists in the implementation of a wireless autonomous and semi-autonomous mobile device, including sensors for detecting the proximity of high-tension...

The invention refers to a system for monitoring the behaviour of the operation of distribution transformers, with the purpose of detecting early faults, where the use of electronic devices coupled to the equipment for performing a diagnosis may help to anticipate flaws before they cause a catastrophe and risk the underground electric installation a...

The experience in operation of electrical equipment has shown that partial discharges shorten the life insulation systems. Therefore, the partial discharge can become the cause of serious economic losses by requiring repairs and early changes in electrical equipment, efficiency loss and safety in the operation of communication systems and disruptio...

The article presents simulation based on finite element technique of the most common faults in three-phase squirrel-cage induction motors. Faults examined in this paper are: rotor broken bars and inter-inter turns short-circuit in stator windings. Fault in rotor broken bars was simulated taking two consecutive bars to see how the flux density is af...

The development of HTS superconductor motors has been focused on the traditional construction, mainly in the magnetic field in radial flux configuration like the traditional electrical motors, for this reason the design and construction of superconductor machines in axial magnetic flux configuration are a new alternative for the development of the...

Recently, the use of solar energy in the dehydration of agricultural products is becoming more common as high yields in the post-harvest products. Investment in technologies for contributing to the producers of food products is an important factor for the development of the productive chains of our country. This paper presents the development of a...

The firing process for clay–brick production in traditional kilns generates atmospheric pollution when industrial and domestic scrap is used as fuel. An alternative is presented here, using the solar energy for clay–brick firing. We are developing a system for clay–brick firing to reach temperatures between 900°C and 1050°C; these temperatures are...

The firing process for clay-brick production in traditional kilns generates atmospheric pollution when industrial and domestic scrap is used as fuel. An alternative is presented here, using the solar energy for clay-brick firing. We are developing a system for clay-brick firing to reach temperatures between 900°C and 1050°C; these temperatures are...

The design and manufacture of a two-axis sun tracking system (rotation-elevation), which controls a heliostat of a solar furnace for clay brick firing is presented. The system works with motors controlled through a personal computen The algorithm for the sun tracking system was developed in a visual programming language, calculates the primary and...

The selection of new compounds for the manufacture of underground power cables, involves a lot of qualification and acceptance testing according to the standards applicable to such cables. All these tests have been performed on samples or complete cable, which implies that the time and production costs of these tests are too large, some having reac...

The proposed solar thermodynamic drying system reduces the traditional dehydration process of Roselle used in the western region of Mexico, from approximately four days to four hours. In addition to the 95% reduction in process time, this system also maintains the Roselle's nutritional content, especially that of ascorbic acid (Vitamin C). The prop...

The present invention consists in developing an aerial monitoring and inspecting device for supervising and diagnosing electric transmission lines, which includes an automatic or semi-automatic wirelessly controlled balloon. The balloon comprises sensors for detecting the proximity of the high voltage lines, sensors for the detection and release of...

A control volume conductance method is discussed in this paper. The method is designed for materials that exhibit heat transfer. Particular attention is put to problems where convection overpowers the mechanism of conduction. The semi-infinite solid which moves with arbitrary imposed velocities along the X-axis and has various surface conditions at...

The necessity of man--machine communication has been increasing day by day because of the great number of approaches that help to make human life agile or comfortable. Health is one of the aspects that has generated more interest in recent years. The optical technologies are new technical tools that are being implemented for medical diagnosis and f...

The necessity of man–machine communication has been increasing day by day because of the great number of approaches that help to make human life agile or comfortable. Health is one of the aspects that has generated more interest in recent years. The optical technologies are new technical tools that are being implemented for medical diagnosis and fo...

A selective oxidation technique for diamond films based on the extended exposure to UV light in air at room temperature was developed and studied by Raman Spectroscopy and Scanning Electron Microscopy. The diamond films were synthesized by the combustion flame technique in open atmosphere by using an oxy-acetylene gas mixture as the carbon source....

The purpose of this work was to design and construct a device to obtain optical tomography images of small objects using a laser with a wavelength of 650 nm. Linear and time-invariant absorption and scattering interactions of photons are considered. The mathematical model describing the propagation of light and the design of the device are explaine...

A spatial micropositioning device for the alignment of substrates employed in thin films synthesis by the so-called combustion flame technique, utilized for producing thin diamond films, was designed and built. A combination of mechanical, electronic and optical components allowed, with high accuracy, the alignment of the substrate during the film...

Optical technologies are new technical tool which are being implemented for medical diagnosis and prescription in various processes related to detection within human blood. They have the virtue of be noninvasive method and nondestructive methods, in addition to being a remote detection technique, sensibility enough as to study the properties of the...

Optical technologies are new technical tool which are being implemented for medical diagnosis and prescription in various processes related to detection within human blood. They have the virtue of be noninvasive method and nondestructive methods, in addition to being a remote detection technique, sensibility enough as to study the properties of the...

An automatic system for surface alignment, which can be employed for the study and optical characterization of samples in many devices, is presented. The alignment is accomplished through a mechanical device, consisting in thr ee stepping motors driving micrometry screws, which in rum allow the tilting of the specimen. Simultaneously, a laser beam...