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Fourier transform infrared spectroscopy (FTIR) is a widely used technique that provides molecular information about the analyzed sample, which is sensitive to the analysis environment and changes in it. Therefore, when the spectrum of a material is acquired, the background must be taken into account, since it is common for the experimental parameters to be modified, the baseline varies as well. For this reason, a semi-automatic baseline correction algorithm is proposed for spectra obtained by Fourier Transform Infrared (FTIR) Spectroscopy. In which, fourth-order Chebyshev polynomials are fitted to points selected by a threshold criterion. The algorithm was applied to the analysis of CaCO3 y SiO2 mixtures, for known concentrations, showing that spectrum information is preserved. On other hand, the method was applied to verify the crystallinity of calcined bones, obtaining that the algorithm considers the shape of the bands. Preserving the physical information of the spectra and eliminating user errors. In addition to considering for band displacements. [ABSTRACT FROM AUTHOR]

We present new data on the exploitation of stone for construction purposes in the protohistory of the southeast of the Iberian Peninsula, specifically from the site of Los Cucos (Bogarra, Albacete) and a possible supply quarry. This study aims to connect the unpublished architectural data with the application of Fourier transform infrared analysis (FTIR). [ABSTRACT FROM AUTHOR]

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Copyright of Conservar Património is the property of Associacao Profissional de Conservadores-Restauradores de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Avances is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Gaceta de la Real Sociedad Matematica Espanola is the property of Real Sociedad Matematica Espanola and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The seismic interpretation step remains dependent on the quality of the data recordings, which are often affected by coherent and inconsistent noises. The main objective of this work is to use the filter "Surface Wave Noise Attenuation", which is based on the Fourier transformation to minimise the surface noise, present on a seismic cross-section summarised in multiple coverage. The proposed filter was applied, in the first stage of our test, to synthetic seismic data on which organised noise was added, while in the second stage the filter was applied to real data, to eliminate as far as possible the ground roll affecting the seismic image before and after stacking. Optimization of the filter parameters allowed an acceptable seismic quality. The use of other filters, the median filter and the Gaussian filter in this case, has reduced the residual noise and the reflectors appear even better. [ABSTRACT FROM AUTHOR]

An analysis of the site effect at accelerograph units from Santiago de Cuba is carried out for the first time in Cuba; using accelerograph records of strong movements corresponding to the Haiti earthquake on August 14, 2021 of magnitude 7.2. The method of direct interpretation of the Fourier transform is used. The main results show that the APTO station, located on the soft soil of marine deposits, beach sand and pebbles, and storm banks, shows the highest amplitude values (APTO 69.625), as well as the highest period values (0.430 s), compared to the ABON station (0.195 s). The maximum frequency value (5,139 Hz) corresponds to the ABON station. [ABSTRACT FROM AUTHOR]

The aim of this research study was to characterize the mycelial growth of the edible mushroom Gymnopus dryophilus and assess its production of β-glucans in a conventional culture medium (potato dextrose) and in an unconventional culture medium (corn flour). Mycelial growth was evaluated in both solid state fermentation (FES) and in liquid state fermentation (FEL) and β-glucans were extracted from an aqueous and alkaline fraction, subsequently were identified by Fourier transform infrared (FTIR) spectroscopy. The results showed higher mycelial growth and production of β-glucans in unconventional culture medium than in conventional culture medium for both types of fermentation. The presence of β-glucans was highest in the non-conventional medium since it contains the greatest quantity of nutrients and its pH favors biomass production. The spectrum of the β-glucans agreed with that reported by FTIR. It is concluded that the unconventional culture medium increases the production of biomass and bioactive compounds (β-glucans). [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper shows the obtaining process of a digital beamformer of multiple simultaneous directional patterns for signals reception using the ARRadio evaluation board. The board is based on the integrated transceiver AD9361 and guarantees the reception, digitization and seending to an FPGA (Field Programmable Gate Array) of the received radio waves by each radiofrequency channel. The FPGA is located on the TR4 Development Board. Communication between FPGA and ARRadio is realized through a high speed connector. On the programmable device are performed AD9361's configuration and control, multichannel calibration process based on Fourier Transform (as method of measuring the delay between channels) and beamforming of multiple simultaneous directional patterns digitally. Simulink is used as design tool for digital system develop. Finally is realized the implementation and experimental verification of multiple digital beamforming system. [ABSTRACT FROM AUTHOR]

The Fourier Transform is applied in the analysis of the surface wear of the annular cam of the highpressure pump DENSO HP3 using the ecological fuel mixture diesel - surfactant - water at 20%, which is an emulsion of two tense-active non-ionic substances during 200 functioning hours at 3000 rpm with inspections performed each 50 hours. The ecological fuel reduces the emissions, enhance the thermal efficiency, torque, and power of the internal combustion motor; as it is shown in the experimental analysis, the precision balance it is detected the reduction of 0.121 grams of mass in the cam, with the digital roughness meter it is determined the roughness Ra on the frontal face of the cam, establishing a 22.23% of wear in relation with the ideal profile of experimentation, for the rear face 40.35% of wear, with the didactic module generated on Matlab for the digital image processing and the Fourier Transform compares the ideal profile and the roughness profile of the annular cam in terms of image frequency, using statistics tools such as the maximum average and the minimum o intensity. The use of the mixture of the diesel-surfactant-water fuel at 20% on the high-pressure pump HP3 generates premature wear on the cam surfaces. With the purpose of generating an investigating contribution, it is included the methodology and the technic of tests and measurements on the dynamometer for estimating the fundamental performance characteristics of the diesel internal combustion motor with this type of fuel. [ABSTRACT FROM AUTHOR]

This work shows a methodology known as the S Transform for time-frequency analysis of different distortions in electric power systems, which mostly are non-stationary and short-duration events, due to the contribution of network impedances and loads types connected by the users. The ability to identify all types of power quality distortions encrypted in the current and voltage signals is very important for failures and malfunctions analysis of monitoring equipment, protection, and control of electrical networks. An important feature of the S Transform is that it combines a frequency dependent resolution of time-frequency space, with information fully connected to the local phase. This allows defining the term of local phase spectrum. Additionally, it shows that amplitude response is invariant from frequency, in contrast to Wavelet and Short Time Fourier Transforms. The following study cases will be simulated by means of PSCAD software: motors starting up and shutting down, line-ground fault, zero-sequence harmonics in a balanced three-phase load, unbalanced three-phase load, a signal with high frequency components and notches presence. [ABSTRACT FROM AUTHOR]

In this paper we present the solution of the stationary Schrödinger equation in the coordinates and momentum representations for three simple problems: the linear potential, the harmonic oscillator and the Dirac delta potential. We verify through explicit calculation that the wave functions obtained in each representation are connected through the Fourier transform, showing that both solutions constitute two complementary representations of the same quantum state. From a pedagogical point of view, this shows that both solutions contain information of equal theoretical value and constitute two complementary representations. [ABSTRACT FROM AUTHOR]

The purpose of this work was to analyze the structural performance of houses located around mining exploitation sites where blasting take place. Triaxial receivers were used in monitoring and controlling the blasting to determine in a timely manner if vibration values generated inside the houses cause damage to the buildings in accordance with local and international standards. The results were obtained from data processing by means of the Fourier Transform and the Transfer Function, calculating the fundamental or resonance frequency on the house and the relative velocity spectrum, PSRV. For speed and distance parameters used, it was obtained that particle velocities for transverse, vertical and longitudinal signals generated by blasting are below the safe verge (3.0 mm / s) recommended by the regulations, so the structure of houses under study are not affected by explosions at the mining sites. [ABSTRACT FROM AUTHOR]

Copyright of Zephyrus is the property of Ediciones Universidad de Salamanca and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Boletin de Geologia is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ciencia e Ingenieria Neogranadina is the property of Ciencia e Ingenieria Neogranadina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The skin cicatrization is a complex and organized process that involves three phases: inflammatory, proliferative, and remodeling. It is essential to analyze this process biomolecularly, in order to investigate and propose new therapeutic strategies that improve the healing or promote regeneration. The objective of this project was to analyze histological and biomolecularly through Fourier Transform infrared microspectroscopy (FTIRM) and its biochemical mapping function, samples of an excisional skin wound, comparing the morphological and spectroscopic changes between healthy skin and scarred skin. An excisional skin wound healing model was standardized using female, NIH strain 8-week-old mice (n = 16), provoking an excisional wound of 1 cm2. Healthy skin (day 0) and scarring skin (day 15 post-injury) were morphometrical, histological, and biomolecularly analyzed by digital picture analysis, histological technique, and FTIRM with its mapping function. The morphometric analysis showed a reduction of the wound area of 87.6% at day 15 after wound. Histologically, in the scarred skin a thinning of the epidermis was evidenced, besides reduced cellularity in the dermis, granulation tissue formation, and disorganized collagen fibers were observed. Spectroscopically, changes between the study groups were appreciated, mainly in the lipid bands and in the protein region. The calculation of the areas under the curve and the biochemical mapping showed a lower concentration of keratin and collagen in the scarred skin, as well as collagen fibers disorganization. The ability of the FTIRM to accurately characterize biomolecular changes in cicatrization process was demonstrated, such as the amount of keratin, collagen, and the deposition and ordering of the collagen fibers associated with their maturation. [ABSTRACT FROM AUTHOR]

This research aimed to evaluate the adsorption process of CN- contained in synthetic aqueous solution, using activated carbon obtained from coffee residue; studying its efficiency and equilibrium and kinetic models. Fourier transform infrared analysis (FTIR), X-ray diffraction (DRX) and iodine number determination were performed to characterize activated carbon. A composite central design (DCC) with three factors adapted to three levels each and 6 central points was applied to study the effect of pH (A), contact time (B) and adsorbent dosage (C); According to the analysis of variance, all the main factors and the AA interaction were significant in the adsorption efficiency of cyanide on activated carbon, whose maximum value reached was 54.68% and 67.65% for the predictive level. According to the coefficient of determination (R2), Freundlich's isothermal model (0.954) and the three kinetic equations of pseudo second order (0.991, 0.993, 0.993) were adjusted to the experimental process. From the results obtained, the active carbon prepared from coffee residue can be used as a potential adsorbent of CN-, contained in aqueous solutions of low concentrations. [ABSTRACT FROM AUTHOR]

The second-order partial differential equation associated with the problem of pricing continuous arithmetic Asian options is presented, together with the application of the Fourier transform on the terms of the resulting equation after a series of variable changes. An analytical solution is obtained for the value of this type of options. [ABSTRACT FROM AUTHOR]

Wear in diesel injection systems is one of the problems that directly affect the efficiency of the consumption of Internal Combustion Engines (ICE). Common rail systems (CRDI) are currently the most used, one of the main elements is the injector needle. The objective of the present work is to evaluate the superficial wear of the cone and needle stem of the Bosch nozzle of the CRDI systems using the Fast Fourier Transform to filter the noise introduced by the portable rugosimeter SHBLST241, ensuring Roughness measurements. The methodology used is of experimental type, values are taken according to their heights and depths. The average distance between the local peaks of the profile being validated analytically, a descriptive analysis is applied to verify the normality of the observations and later the Fast Fourier Transform is considered for the investigation of the noise, the same that will be characterized by the type of distribution or function of probabilistic density of the present amplitudes. In the experimentation elements new were considered that served as a reference for the analysis of the pieces used. A graphical interface was developed in Matlab for the Fourier study. The results obtained show low percentages of differences between the data obtained by the rugosimeter and the analytical calculation of Ra, in the cone of 0.07% for the new and 0.35% for the used, in the stem 3.1% for the new one and 0% for the used; It is concluded that the through FFT processing reduces the noise in the data acquisition. [ABSTRACT FROM AUTHOR]

The study of the temporal processing of acoustic signals by the auditory system becomes increasingly important for the development of new strategies for diagnosis and treatment of people who are deaf or hearing impaired. In this work we evaluated different methodologies --chirp analyzer (AFM), short time Fourier transform (TFTC) and continuous wavelet transform (TWC)-- for the reliable estimation of an auditory electrophysiological response known as envelope following response (RSM). These methods could be used in the study or diagnosis or both of hearing problems in clinical practice. Using simulated and real data, the autors compare the robustness and reliability of the three methods to analyze data with different levels of noise and response forms. We found that in general, the three methods provide a reliable estimate (in the sense of accurately recovering the simulated response) of the RSM simulated with different shapes, when there are low levels of noise. The AFM method is the fastest and most robust to noise, while the TFTC estimates the amplitude of the response with a systematical bias. The TWC is very sensitive to noise, overestimating the amplitude of null or very small responses. The RSM estimated with the three methods, from electrophysiological recordings of adult rats, were similar to those given by the method most commonly used in the literature. The results suggest that the AFM is a useful tool for estimating the RSM and should be validated for application in the clinical practice. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Fourier transform provides a physical link with optical theory. This work presents a simple relationship but valuable academically, between the diffraction of light through a long slit under the Fraunhofer criteria and possibilities of its complementary analysis using imaging processing. [ABSTRACT FROM AUTHOR]

Copyright of Avances en Ciencias e Ingeniería is the property of Avances en Ciencias e Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iteckne is the property of Universidad Santo Tomas, Division de Ingenierias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iteckne is the property of Universidad Santo Tomas, Division de Ingenierias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Iteckne is the property of Universidad Santo Tomas, Division de Ingenierias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper shows the experimental procedure used to record the vibrations generated by the passage of a train in a fixed point of the rail. Moreover, it also shows how to identify and characterize a defect on the surface of a wheel, by analyzing the joined time-frequency domain of these vibrations, using the short time Fourier transform -STFT. The results demonstrate the advantages of the STFT in this application, and that the use of a monitorizazing system of the vibration generated on the railway line is efficient and practical to implement a predictive maintenance of the train wheels. [ABSTRACT FROM AUTHOR]

A new material was synthetized using the wet precipitation method to obtain an osseous insert that can be used in medical applications. A solution of CaCl2 198 mM and another one with 119 mM of (NH4)2HPO4 dissolved in distilled water were simultaneously prepared with the slowly and continuous addition of NH4OH dissolved in water . Finally, 3 ml of collagen was aggregated to the solution. The precipitated was washed out several times with distilled wáter, filtered and dried in an incubator at 40°C. The samples were characterized by X-ray diffraction, surface electronic microscopy, Fourier transformation based infrared spectroscopy. Three different cubes composites with the volume of 10 x 10 x 10 mm3 each one were prepared and implanted into the dtygre sacrum of a female dog to check the osseous integration and the biocompatibility of the new material. Histological and radiographic studies were developed showed the development of osseous callus and the consequent formation of new bone section. [ABSTRACT FROM AUTHOR]

The well-known Fresnel integral relates a known complex wave defined in the object plane (the input wave field) to the observable complex wave (the output wave field) defined in the image plane after free-space propagation; this means that if the object and image plane are parallel to each other, corresponding imaging system is said to be linear-shift-invariant (LSI). This advantageous property was essential for the development of phase sensitive imaging techniques; however, if the image plane is inclined with respect to the incident beam, the effective propagation distance will vary over the image plane, consequently, the imaging system is not shiftinvariant. In this paper an extension of the theoretical formalism of Fresnel diffraction to the case of an inclined image plane is proposed using the fractional Fourier transform. [ABSTRACT FROM AUTHOR]

The quantitative analysis of electroencephalographic activity (EEG) constitutes a useful tool that makes it possible to relate changes in cerebral electrical activity to cognitive and behavioral functions under a variety of experimental conditions. Their recording and analysis are currently carried out primarily through the use of computer programs. This study presents a computerized program (EEGmagic) that was elaborated for the Windows operating system using the Delphi language, and that is designed to analyze EEG signals and facilitate their quantitative exploration. To do so, the program applies Rapid Fourier Transform to the EEG signals of one or more groups of subjects in order to obtain both absolute and relative potentials spectra. It also calculates the correlation spectra, both interhemispheric and intrahemispheric, and, finally, applies parametric statistical analyses to these potential and correlation spectra Statistical analyses are applied to each individual frequency and to frequencies grouped in bands Unlike other programs, EEGmagic is simple and inexpensive. It obtains the results files with the corresponding statistical significances rapidly and with precision; thus, EEGmagic may constitute an important tool for the study of cerebral functionality and behavior. [ABSTRACT FROM AUTHOR]

An experimental setup, illuminated by a DPSS Nd: YAG laser λ=532nm, was used to study the basic optical performance of an epitaxial confocal array, and to compare it with a conventional objectives array. The Point Spread Function (PSF) and the Optical transfer function (OTF) were determined; and the smallest resoluble size (resel) was calculated, obtaining spatial resolutions of 4.4 µm and 7.2 µm, for 10X and 40X objectives respectively. Confocal experimental results are presented and compared between them and with other author's theoretical calculations, illustrating the advantages offered by confocal systems [ABSTRACT FROM AUTHOR]

In the present paper a digital algorithm was developed to make phase encryption of digital indexed images to color using the fractional Fourier transform. The indexed image to encrypt is placed as the phase of a complex exponential, then is transformed three times and multiplied in intermediate steps by two random phase masks statistically independent thus to obtain the encrypted image, for decrypt the coding image the encryption procedure is applied in the inverse sense to the conjugated complex of the encrypted image. In the implemented cryptographic algorithm five keys are used, constituted by three fractional orders and two random phase masks, all these keys are necessary for a correct decryption providing a dependability to the transference of images by means of the communications nets. [ABSTRACT FROM AUTHOR]

The Fresnel zone plates are described suitably with the help of the classic theory of the diffraction; in this particular case when a plane wave illuminates a certain type of bicomponent optical system, consisting of plane screens with circular apertures on a given optical axis, a multifocal diffractive focusing effect can appear; this configuration allows to obtain small regions with much intensity, here the diffraction picture in the focal planes represents the circular nonlocal bands of the Fresnel zones with a bright narrow peak at the center. In this article a detailed description of the working principle of the Fresnel zone plates and general equation for the Fresnel zonal plate diffraction is derived within the framework of the fractional Fourier transform. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The closed-form propagation equation of Gaussian beams through a paraxial optical ABCD system is derived using the fractional Fourirer transform and its general applicable advantage is illustrated with numerical examples. [ABSTRACT FROM AUTHOR]

An automatic system was developed for the positioning of opticals fibers, through step motors of 1.8° (0.9° to Half step) controlled by a PIC16F877A Microcontrolator, an analog digital converter, an USART for the interaction with the PC. The software was elaborated under the Visual Basic 6.0 platform, which allow the automatic positioning of optical fiber in the place where the fourier transform is formed. [ABSTRACT FROM AUTHOR]

In this paper we study image compression as a way to compare Wavelet and Fourier models, by minimizing the error function. The particular problem we consider is to determine basis {ei} minimizing the error function between the original image and the recovered one after compression. It is to be noted or remarked that there are many applications in such diverse fields as for example medicine and astronomy, where no image deteriorating is acceptable since even noise is considered essential. [ABSTRACT FROM AUTHOR]

The periodic nature of the fabric images allows using fast Fourier transform techniques in image processing for its characterization. Due to the repetition of patterns inside the images of textile, is possible to find a form relatively easy of description in their energy spectrum. A recent work outlines a group of geometric descriptors for the Fourier spectrum of the images; looking for this efficiency to rotation, translation and scale change invariance [1]. These descriptors showed to be very effective to represent a textile fabric and can be used to characterize the quasi periodic textures in real time and in situ non destructive techniques. Samples of textile textures are tested to this technique of parametric representation with the purpose of analyzing their robustness and reproducibility. Finally, a set of textile fabrics is subjected to this model with the aim of evaluating the possibilities to carry out classification, verification and pattern recognition. [ABSTRACT FROM AUTHOR]

In this work adherent (AR) and non-adherent (NAR) rust, formed on low carbon steel coupons exposed to total immersion corrosion processes in a 0.6 M NaCl solution, were obtained. The immersion was realized for 7 days. The Mössbauer spectra (MS) of the AR show the presence of lepidocrocite (γ-FeOOH), goethite (α-FeOOH) and/or akaganeite (β-FeOOH) phases plus a spinel phase. On the other hand the γ-FeOOH/β-FeOOH and the possibly superparamagnetic goethite phases were more abundant in the NAR samples. The Scanner Electronic Microscopy (SEM) images show clusters formation in both AR and NAR with mean particle size of 1.6 and 4.4 µm, respectively. The chemical composition measurement obtained by energy dispersive X ray shows 71.49 y 77.87% on weight of iron in AR and NAR, respectively. In addition, vibrational bands asociatted to the different phases which were found by MS, were identified using diffuse refectance infrared Fourier transform (DRIFT). [ABSTRACT FROM AUTHOR]

In this work the implementation of a digital correlador for images was carried out simulating an optical system 4f or Vanderlugt arquitecture. The correlator uses the fractional Fourier Transform to carrier out the processing. The Fourier transform allows analyzing different orders so much in the transformed image as in the filter and the inverse transform of the product. The arithmetic takes advantage of high speed offered by the parallelism of the digital processor of the TI model DSP TMS320C6711 used. The performance is analyzed by metrics SNR, PCE, OE and PSR. [ABSTRACT FROM AUTHOR]

In the present article it is studied the automatic recognition of the signal of speech using for this the Fourier's transform and the Neural. Networks. The characteristics of the speech will be discriminated in the domain of the frequency and we will proceed to train a Neural. Networks that is capable of distinguishing the different patterns. With the trained network it is classify the diverse patterns to use them as commands to realize functions of control. [ABSTRACT FROM AUTHOR]

An correlator has turned into a very important tool for the information processing, such as the sig-nal recognition. With the generalization of the standard Fourier transformation; the introduction of the spherical emitters and receivers, and based on an alternative definition for the fractional convo-lution and correlation, we proposed an hybrid architecture of fractional correlation (JTC fractional) that allows us to correlate images. In the construction of the correlator a bi-prism is just used in front to the correlating images. The peaks of fractional correlation are calculated by simulation, and then they are compared with the results obtained for the hybrid processor implemented. [ABSTRACT FROM AUTHOR]

Time-frequency representations is showed in this work for analysis of the seismic data in applications with spectral resolution and filtering, the first is the Gabor transform and the other is the Fraccional Forier transform, both provide, to the siesmic data a affective tool for the spectral treatment, also is good for saying that the procedure were on synthetic signals for after to execute on real data, in it case the main step is the processing of the signal. [ABSTRACT FROM AUTHOR]

A new image analysis technique has been developed which allows maceral analysis of coal to be carried out. The technique is able to separate the liptinite, vitrinite and inertinite component from the background resin by using quantization method, this method identify the five most important colors in each image of each maceral. The colors images identified are introduced in the Vander-Lugt correlator to be compare with images coal's microstructures without characterize and show the correlation's peaks. [ABSTRACT FROM AUTHOR]

In the following paper is presented a detailed study of the Bragg's Law by means of the Fraunhofer's diffraction using the interferences diagram that is obtained when illuminating a diffraction grid; the analysis is development in a theoretical, digital way and with experimental implementation, with the help of the pattern of complex amplitude obtained as a mere formality of the Fourier's Standard Transformation, finding this way the regions of; Constructive interference, and destructive Interference, in which one has that the separation among the regions is inversely proportional to the separation among slits of the grid, but directly proportional to the wavelength of illumination and the separation between the grid and the screen like it shows it the classic result of the Bragg's Law. [ABSTRACT FROM AUTHOR]

The Fresnel diffraction in approach paraxial is shown that it corresponds mathematically to Fourier transformation among spherical surfaces; that which gives origin to the operator Fourier sphere and the step of a spherical wave with well-known curvature radius through a thin lens and observation over spherical wave corresponds mathematically to the transparency curvature operator. The composition of these operators allows find in a way but simple the laws of propagation of the waves in the free space, with the application of the two operators, is possible to obtain the field electromagnetic transfer of general form of the emitter to the receptor, separated by a distance. [ABSTRACT FROM AUTHOR]