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Non-destructive techniques for characterizing materials in-service have been increasing in importance. Thus, it is relevant to assess the potential of non-destructive techniques for solid materials. This work aimed to determine the modulus of elasticity of Bertholletia excelsa wood using the particle image velocimetry technique and the ultrasound method to compare the results with the conventional methodology. For this purpose, samples of Bertholletia excelsa were made using a circular saw. The samples were evaluated for sound propagation to calculate the modulus of elasticity using ultrasound equipment. Subsequently, they were subjected to the compression parallel to grain test in a universal testing machine. The samples were marked and monitored during the loading session, with the repeated capture of images using a professional camera. The deformation values obtained were used to estimate the modulus of elasticity using the particle image velocimetry technique. The mean values of modulus of elasticity found were 17403 MPa for ultrasound, 15589 MPa for the particle image velocimetry technique, and 15333 MPa for the universal testing machine. The particle image velocimetry technique was considered to be statistically similar (Tukey α = 0,05) to the other methods tested. The linear coefficient of determination (R2) between the particle image velocimetry technique and the universal testing machine was 0,95, a high and satisfactory value. Thus, the particle image velocimetry technique and the ultrasound method are valid to estimate the modulus of elasticity of Bertholletia excelsa wood and possibly of woods with similar technological characteristics.

Several non-destructive testing techniques have been improved and tested in recent years. The non-destructive testing techniques using particle image velocimetry (PIV) and digital image correlation (DIC) differ from conventional testing techniques, as they allow making measurements indirectly. In this study, the elastic modulus in wood beams of Eucalyptus grandis and Pinus oocarpa were determined using PIV and DIC. The application of PIV and DIC techniques occurred during the static bending tests, when the displacements were also measured by the conventional method. The applied load values allowed calculating the elasticity modulus. In all regions of analysis, the mean values of the elasticity modulus found by the DIC, PIV and conventional method are statistically equivalent. It is concluded that the PIV and DIC testing techniques can be used to determine mechanical properties of wood.

Dynamic laser speckle (DLS), or even biological laser speckle (BLS), is an interference phenomenon that was transformed in a sensor to get information from the activity of biological material. And this is due to the dynamic interference of the laser beam with the illuminated sample, that creates a pattern which changes in accordance to the changes in animal tissues or in human blood flow, in seeds or in fruits, as short examples of the broad applications of this phenomenon and sensor. Despite the many reported applications, the main limitation of the use of DLS is its limited use in optical laboratories, and thus the low accessibility to final users. This work aimed to test the key conditions to adopt the DLS using a mobile device, a smartphone, to capture and to analyse the data. In the data acquiring it was tested the ability to setup the ISO, the white balance, and to fix the zooming. The speed of the image or video acquiring was also tested, the last associated to extraction of frame functions. The analysis of the data was evaluated, first testing the conditions to program the equations of the traditional methods, as well as its time consuming without fails or breaks. The tests showed that the DLS can be implemented in a feasible way in smartphones, being able to assemble images with quality and speed necessary to DLS, as well as, being able to run the main methods in reasonable time, without breaks. The achievement opens an accessible way to use the DLS in many areas of knowledge by the final users, as well as a way to create embed systems using the smartphone of even tablets as part of the equipment.

The Biospeckle Laser (BSL) induced phenomenon is recorded as light scattered from the surface of illuminated test material, and the methodology is established as a tool for the non-destructive assessment of biological tissues. The output of BSL-based recording is normally numeric data that are processed to generate graphical and visual information. However, BSL outputs could presented in a qualitative audible format as a rapid means by which a test-tissues physiological states may be classified. Here we report a new BSL-data processing methodology that was able to discriminate viable and dead beans (seeds) of coffee (Coffea arabica L.) using single- and multi-frequency wavelength models. BSL-data was rapidly converted from the traditional numeric (graphical) output into forms (‘biospeckle index’) audible to the human ear. The utility and significance of this novel BSL-audio approach is discussed.

Throughout their useful life structures demand monitoring to verify their conditions of use. Thus, the need arises to seek methodologies capable to evaluate displacements and deformations in structural components of buildings. The objective of this research was to evaluate the use of the particle image velocimetry (PIV) technique to analyze test specimen behavior during a static bending test, additionally a displacement map is presented. The PIV technique measures variations of position of a region in an object from consecutive images from a loading session. The tests were performed on wood of Pinus oocarpa and Eucalyptus grandis, plywood panels, laminated veneer lumber (LVL) and oriented strand board (OSB). The results obtained by the PIV technique were compared to values obtained from dial indicators. It was verified that in all the materials tested, the PIV technique presented results similar to those found in the dial indicators. By means of the Student t test, with a significance level of 1%, some regions of analysis the values found by the PIV technique and the dial indicators were statistically similar. For the analyzed regions that did not achieve statistical equality, a correction equation was calculated (R² higher than 0.99). It was concluded that the PIV technique, with properly adjusted setup, presented results similar to those obtained in the conventional tests, proving its accuracy and reliability in displacement measurements, with the advantage of being a non-destructive and contactless structure monitoring technique.

The biospeckle, or dynamic laser speckle, is used as a potential tool to monitor activity in many biological and non-biological materials from agriculture to medicine, and it is usually based on the use of He-Ne and diode lasers, the latter of which has great potential to be embedded in portable equipment. Some queries about the stability of the diode laser were raised, such as the real influence of the mode hopping phenomenon as a drawback in solid-state devices in comparison to the well-known He-Ne lasers, and thus we decided to test it . In addition, we present an alternative way to enhance the stability and the signal-to-noise ratio of the information using a relative index rather than the absolute and single data traditionally provided and analysed. We compared the He-Ne and diode lasers using a power light sensor, and the usual dynamic laser speckle indexes (DLSI). We tested both cases using a clean and inert surface, as well as a drying paint process. To test the relative index, we used two different temporal series of speckle patterns and created a signal-to-noise ratio in dB, using a drying paint process, and in a raw data of a drying paint process associated to a drop of alcohol. The results show that the stability of the diode laser is greater than that of the He-Ne laser in all cases, breaking the paradigm of the stability of He-Ne devices. The signal-to-noise ration showed reliable results when the named dynamic laser speckle relative index (DLSRI) in dB was adopted.

Displacements in structural columns have many challenges regarding to monitoring since it is a complex phenomenon. The monitoring of steel column subjected to buckling is one challenge in order to identify its structural behavior based on displacement measurements. In some cases, this effect is studied under steel rectangular column subjected to axial compressive loads. It is necessary in order to quantify the horizontal column deformation by using optical techniques based on displacements from images to evaluate its structural behavior. This paper is aimed to apply the Particle Image Velocimetry (PIV) technique as a robust and cheap optical method on buckling study of columns as a contactless measurement technique compared to Finite Element Method (FEM). Experiments using rectangular bar samples were used to evaluate the behavior of columns under axial compressive load causing the buckling effect. In order to quantify displacements, PIV technique was applied based on pre-defined positions of the points in the images and the column displacements were measured and compared to FEM. Results indicated displacements difference around 1.08% between PIV and FEM, providing that PIV technique can be used to quantify column displacements in a plane when compared to FEM results. This allows PIV applications for any structures monitoring such as building, bridges and silos.

Water is one of the main components of food and its presence is related to the rate of deterioration of foods. Thus, control of the water activity (aw) is a fundamental feature of food technology. The methods currently used for determining aw of foods mostly use the relative vapor pressure of the product to quantify the aw at constant temperature. This last factor limits evaluation of the aw because the instrument used is not capable of determining the aw at temperatures lower than 25 °C and/or at negative temperatures. In this study, the potential of the biospeckle laser for aw measurement was evaluated. Contrast analysis using the biospeckle laser technique provided statistically significant differences in the concentrations and aw for lithium chloride solutions and model solutions of pectin and sucrose at temperatures of 0, 5, 10, 15, 20, and 25 °C, as well as at freezing temperatures. After calibration of the biospeckle laser with the lithium chloride solutions, aw of corn starch, oatmeal, and wheat flour was determined at different temperatures, with errors lower than 20%. This achievement provides a platform for developing protocols to measure the aw of foods at different temperatures using the biospeckle laser.

The most important parameter in terms of material mechanical behavior knowledge is the modulus of elasticity, being traditionally obtained through destructive tests. The objective of this study is the verification of the potential use of the particle image velocimetry technique (PIV) as a tool to obtain the modulus of elasticity in sawed wood samples (Pinus oocarpa and Eucaliptus grandis) and wood panels (Plywood, LVL and OSB). The PIV technique has as characteristics the low cost of equipment, fast results, no need for contact with the object tested, accuracy and possibility of application in the field. The application of the PIV technique occurred during the static bending tests where the deformations were also measured with a dial indicator (conventional method), thus obtaining comparative measurements. From the load values applied by a universal test machine and deformation values obtained by the dial indicator and PIV techniques, it was possible to calculate the modulus of elasticity through both methods. With the “Student's t” statistical test application with significance level of 1%, it was verified that the modulus of elasticity found by the PIV technique and the dial indicator were statistically equal. Average values for the modulus of elasticity found were respectively for the use of the conventional method and for the PIV method the values of: 13,077 and 13,027 MPA for Eucalyptus grandis; 6,171.6 and 6,418.8 MPa for Pinus oocarpa; 10,481.2 and 11,094.3 MPa for plywood; 8,687.4 and 10,261.0 MPa for the LVL; and 2,480.1 and 2,899 MPa for the OSB. It was concluded that the PIV technique is capable of measuring modulus of elasticity values with similar precision to the test techniques traditionally used for this purpose.

This paper tests some traditional methods to analyze dynamic laser speckle regarding their filtering actions. Additionally, we propose two new biospeckle indices based on the binary entropy, including one that avoids filtering the original signals. The work was based on theoretical developments and was validated using a drying paint monitoring test. We proved that the dynamic laser speckle, or biospeckle, is compromised by filtering actions and that it is possible to elect an index that does not provide filtering.

We analyse how the frequency bands influence the independence of speckle index values from the level of illumination in a dynamic laser speckle analysis. Specifically, we study how the temporal speckle deviation index is influenced by the use of three different frequency bands of the speckle signal. Finally, it is shown how signals with high frequency components return values with greater independence of the level of illumination.

The expansion of the agricultural frontier and recurrent disturbances caused by intensive tillage practices are factors of exposure and degradation of the physical, chemical and biological properties of soil. When the soil is uncovered, the rain causes changes in its surface structure enabling the development of crusts. Surface crusting is a major detrimental issue to agriculture, as it damages the soil structure, reducing the water infiltration, thus modifying soil roughness and porosity, which increases run-off and erosion. Therefore, the monitoring and control of the occurrence of crusts must be continuous; however, the traditional techniques used to do that demand contact and destruction of the observed soil surface as well as time. This opens room for optical techniques that are potential tools in soil surface analysis in a fast, contactless and non-destructive way. Driven by this motivation, the present study developed a non-destructive, robust, low-cost, portable optical method for characterizing soil surface crusting. Images of samples with and without crusts in the laboratory as well as in the field were illuminated and recorded, with identification of parameters that could be related to presence or absence of surface crusts. The results confirmed the feasibility of using an optical technique as a contactless and non-destructive method for differentiating surface crusts in the field that can be also embedded in portable and low-cost apparatus.

Dynamic laser speckle phenomenon allows a contactless and nondestructive way to monitor biological changes that are quantified by second-order statistics applied in the images in time using a secondary matrix known as time history of the speckle pattern (THSP). To avoid being time consuming, the traditional way to build the THSP restricts the data to a line or column. Our hypothesis is that the spatial restriction of the information could compromise the results, particularly when undesirable and unexpected optical inhomogeneities occur, such as in cell culture media. It tested a spatial random approach to collect the points to form a THSP. Cells in a culture medium and in drying paint, representing homogeneous samples in different levels, were tested, and a comparison with the traditional method was carried out. An alternative random selection based on a Gaussian distribution around a desired position was also presented. The results showed that the traditional protocol presented higher variation than the outcomes using the random method. The higher the inhomogeneity of the activity map, the higher the efficiency of the proposed method using random points. The Gaussian distribution proved to be useful when there was a well-defined area to monitor.

Desde que Gallager introduziu o algoritmo de decodificacao Bit-Flipping (BF) com decisao abrupta para codigos Low Density Parity Check (LDPC), outras duas variantes foram propostas por Sipser e Spielman para os codigos conhecidos como "Expander Codes". Posteriormente, uma versao da decodificacao BF por decisao suave conhecida como decodificacao Modified Weighted BF (MWBF), foi investigada. Esta tese propoe versoes modificadas dos algoritmos de Sipser e Spielman. Resultados de simulacoes para codigos Low Density Generator Matrix (LDGM) sistematicos, com comprimento longo mostraram um melhor desempenho da versao proposta. Adicionalmente, para um comprimento medio dos codigos LDGM, resultados de simulacoes mostraram um desempenho similar a decodificacao MWBF com a vantagem de nao ser necessario o uso de operacoes em ponto flutuante. Abstract