Gerardo Miramontes de León

SCALE-INVARIANCE OF NORMALIZED YEARLY MEAN GRAIN YIELD ANOMALY SERIES

In crop science, tools of non-linear dynamics, fractals, chaos, intermittency and self-organized criticality may be employed and applied to the analysis of spatial variability and temporal behavior of agro-meteorological variables, soil properties, plant attributes, commercial yields, and prices of the agricultural products in order to gain knowledge about underlying complex processes. A search on the occurrence of particular scaling laws in Mexicos normalized yearly mean grain yield anomaly series of maize (Zea mays L.), beans (Phaseolus vulgaris L.), wheat (Triticum aestivum L.) and rice (Oriza sativa L.), using a variography approach is reported in this work. Additionally, power spectrum determination, time-frequency analysis, and estimation of Lyapunov exponent were performed for each profile in order to obtain useful information on the frequency contents and signs at which important frequencies occur as well as to determine their sensitivity to initial conditions. Fractal analysis gives us the order maize

Analysis of AVI Files for Mice Behavior Experiments in the Morris Water Maze

A computer vision program to perfom the analysis of AVI files that were captured during Morris water maze tests is presented. The experiments were performed with a sample of 25 rats that received different medical treatments. The system accepts as input a video AVI file and extracts information, such as escape latency or elapsed time, average velocity and total distance. These measures are suitable to behavioral studies on rats. The results show the reliability of the system, although some dificult conditions were present, such as camera mis adjustments, low quality videos, and changes in ilumination.

A data driven model of laser light scattering in metallic rough surfaces

A new model of laser light scattering was obtained from experimental profilometer data and ray casting technique. Modelling was based on variables common to an angle resolved scatterometer and geometric optics. With this model, it was possible to obtain the scattering patterns, masking and shadowing effects, multiple lobes and backscattering. As advantage of the model, it was unnecessary to make statistical assumptions about the slope distributions. Satisfactory results were obtained from very small Ra values (0 m) to relatively large values (7.53 m). With no modifications or additions to the model, for different surface profiles, off-specular and multiple lobes were obtained. A complete set of equations is given, detailing the construction of the model. In addition to reproducing the scattering patterns reported in the literature, it was found that, if measured profilometer data are used, for large roughness values and large incidence angles, the scattering pattern does not hold the Helmholtz principle.

Real-time turning surface inspection using laser light scattering

An optical system for real-time measurements on a turning surface was designed and implemented in the optical metrology laboratory at CICATA-IPN. Different profiles of machined parts can be determined using a single detector or a photo-diode array. The basis of the measurement is the scattering of a laser beam which is reflected by the turning surface. Two different configurations were tested, the first one uses a single photodetector and a commercial lock-in amplifier, and the second uses a photodetector array and a proprietary platform. The samples under test were mounted on two different lathes for each configuration. The samples were rotating while the measurements were taken by the electronic system. Under these conditions it was possible to detect the intensity changes of the scattered light in the single detector case, and changes of the spread in the intensity distribution in the multidetector case. With the acquired data, qualitative profiles of the samples were obtained, with promising results. Potential applications in industry are straightforward when surface inspection is necessary to asses products quality.

A Lowpass Pulsed Excitation and Method for Polarization Resistance Measurements

A new method to measure the polarization resistance on electrochemical cells is proposed. The method is based on the application of a new pulsed excitation, which exhibits low pass frequency contents, and time domain analysis. In other pulsed excitation methods, curve fitting algorithms are used to find values for equivalent RC models. In our approach using this pulsed excitation, single values of potential and current measurements, at a very precise time, are needed to obtain the value of the polarization resistance. A numerical simulation was first developed and then, the method was tested using equivalent analog circuits and electrochemical cells. The pulsed excitation method was also compared with electrochemical impedance measurements, where the modulus of the impedance, at the minimum testing frequency, was taken as an estimation of the polarization resistance. According to the experimental results, the proposed method can be used in new instrumentation designs, where the main goal is to obtain a value of the polarization resistance.

FPGA Implementation of a 16-Channel Lock-In Laser Light Scattering System

The use of optical techniques for the measurement and characterization of physical phenomena is of great interest in the scientific and industrial communities. This work shows the implementation of an integrated system for measuring Multi-angle Laser Light Scattering on a Field Programmable Gate Array. The embedded design delivers a compact and highly competitive system. The system is able to display, in real-time, the light intensity from a photo detector array showing in this way the corresponding pattern distribution of the scattered light at 16 sensing points. Some laser light scattering patterns from metallic samples with different roughness are shown.