Roberto Alves Braga Júnior

Laser speckle techniques in quality evaluation of orange fruits

This work presents a study of a new technology applied in quality tests of oranges. Evaluations were performed using a nondestructive and noninvasive method based on the interpretation of an optical phenomenon that occurs when the fruit is illuminated with coherent light, referred as biospeckle. The speckle patterns of laser light scattered in orange fruits have been measured through their quantification. For the quantification of the variation by biospeckle, the autocorrelation function and the modified occurrence matrix were used. From these functions, two parameters were obtained: the statistical cummulant and the moment of inertia, calculated from the modified occurrence matrix. These values were used as quality and senescence indicators for the specimens and were compared with other parameters, as total soluble solids, total acidity, the penetration force and the storage period. It was observed that the moment of inertia and statistical cummulant decrease during the storage period. Since senescence is dependent on the storage period, it was possible to observe that the measure of the dynamic speckle varies for fruits as their quality decrease, and also the values change with the position where the images are taken.

Development and validation of a model to compute the surface area of broiler chickens

Surface area (As) of poultry is an important input parameter in heat and mass transfer calculation; thus, it was aimed with the present work to develop and to validate an empirical model to estimate the broiler chickens surface area. Eighty four Ross broiler chickens were used in this research, thirty seven male and forty seven female, with body masses during all growth phase. In the laboratory, each randomly selected chicken had its dimensions (length, width and height) and body mass evaluated. The chicken skin with feathers was taken off to determine As. Portion of the data was used to fit the equation to estimate the surface area and another portion was used to validate it. Results showed that the empirical equation to determine As was statically significant (P 0.05).

Diagnóstico da automação na produção leiteira

Objetivou-se neste trabalho realizar um diagnostico da automacao na producao leiteira na regiao sul de Minas Gerais, enfatizando os tipos de automacao existentes, melhoria do processo produtivo nas propriedades leiteiras com adocao da automacao e as dificuldades enfrentadas para a sua implantacao. A metodologia utilizada baseou-se na pesquisa qualitativa, por meio do estudo exploratorio. Os resultados indicaram que existem varias opcoes de equipamentos que automatizam processos na producao leiteira. O estudo permitiu verificar tambem que a grande dificuldade enfrentada pelos produtores para automatizar as propriedades leiteiras e o alto custo dos equipamentos e a realidade da automacao existe apenas para os grandes produtores de leite.

DIGITAL SURFACE AREA ASSESSMENT OF BROILER CHICKENS

Surface area (SA) of poultry is an important parameter for heat and mass transfer calculations. Optical approaches, such as the moire technique (MT), are non-destructive, result in accuracy and speed gains, and preserve the object integrity. The objective of this research was to develop and validate a new protocol for estimating the surface area (SA) of broiler chickens based on the MT. Sixty-six Ross breed broiler chickens (twenty-seven male, thirty-nine female, ages spanning all growth phases) were used in this study. The dimensions (length, width and height) and body mass of randomly selected broiler chickens were evaluated in the laboratory. Chickens were illuminated by a light source, and grids were projected onto the chickens to allow their shape to be determined and recorded. Next, the skin and feathers of the chickens were removed to allow SA to be determined by conventional means. These measurements were then used for calibration and validation. The MT for image analysis was a reliable means of evaluating the three-dimensional shape and SA of broiler chickens. This technique, which is neither invasive nor destructive, is a good alternative to the conventional destructive methods.

Calibração da técnica de moiré aplicada a perfilometria de protótipos mecânicos

A perfilometria e uma tecnica amplamente utilizada na construcao de mapas e graficos de relevos aplicados a uma vasta area do conhecimento. Frente as necessidades de suprir a demanda da industria e da area de desenvolvimento de prototipos quanto a tecnicas nao invasivas na investigacao da superficie de materiais em geral, o presente trabalho buscou propor uma metodologia de calibracao aplicada a tecnica de moire para investigacoes perfilometricas em prototipos mecânicos buscando baixos custos e flexibilidade. A tecnica de moire consiste na comparacao de dois reticulos periodicos, onde um segue o comportamento da superficie do objeto (reticulo modelo - Rm) e outro nao esta deformado, seguindo o comportamento de um plano de referencia, (reticulo de referencia - Rr). A luz que passa entre os reticulos se sobrepoe formando padroes de moire ou franjas de moire que se comportam como ondas senoidais. Nos ensaios de calibracao, usou-se um cone de relevo conhecido para a determinacao de uma constante de correcao de mapas gerados digitalmente. Os ensaios realizados aplicaram a metodologia para a determinacao do perfil de um mouse de computador e para a determinacao da deformacao de uma chapa metalica. A metodologia proposta para a calibracao da tecnica de moire mostrouse capaz de realizar os mapeamentos, com resolucao maxima na ordem de centesimos de milimetros, podendo entao ser usada em aplicacoes com niveis de precisao inferiores a essa ordem.

Desenvolvimento de um modelo para o biospeckle na análise de sementes de feijão (Phaseolus vulgaris L.)

O biospeckle e uma figura de interferencia formada pela reflexao difusa da luz coerente espalhada ao interagir com um objeto que apresenta algum tipo de atividade, biologica ou nao. O padrao de interferencia se modifica ao longo do tempo devido as estruturas responsaveis pelo espalhamento estarem em atividade. Esse fenomeno tem sido estudado com o intuito de se desenvolver um metodo rapido e nao destrutivo para avaliacao de materiais biologicos. A obtencao de um modelo simples que descreva os aspectos essenciais do fenomeno e um importante passo para o dominio da tecnica. Neste trabalho e apresentado um modelo para descrever a formacao do biospeckle, desenvolvido a partir de hipoteses simples sobre como o tecido biologico difrata a luz coerente e qual o efeito da atividade biologica sobre a difracao. Foram comparados os resultados da simulacao do modelo com resultados experimentais obtidos de sementes. O modelo reproduz com sucesso algumas das caracteristicas basicas do padrao dinâmico.

Recuperação da topografia de ovos por meio da técnica de moiré e calibração independente

The recovery of the topography of eggs using digital images analysis allows the prediction with a non-destructive and with a non-contact way of the egg mass, yolk, egg white, and eggshell, which are products widely used in the industrial sphere. The present research seeks to develop a methodology to recovery the tridimensional shape of eggs through image analysis, in particular by the moire technique with the proposition of an independent calibration. For the accomplishment of this research, eggs of different sizes classified in XL (more than 73g), L (63 to 73g), M (53 to 63 g), and S (until 53 g) were used. In each test realized at the laboratory, one egg, randomly selected was illuminated with the projection of grids and the images were taken and processed to obtain the tridimensional shape of the object by moire technique (TM). The dimensions of its main axes were measured by means of a caliper rule, being used as a reference for the TM calibration. Empirical equations were adjusted for the correction of the dimensions, presenting coefficient of determination of 0.961, 0.955, and 0.988. TM showed to be adequate for recovering the egg topography providing errors smaller or equal to 5.47%, with a clear demand of an independent calibration in the three dimensions, and without any standard object.

UTILIZAÇÃO DA TÉCNICA SUNSET LASER PARA DISTINGUIR SUPERFÍCIES USINADAS DE MADEIRA COM QUALIDADES SIMILARES

The ASTM D 1666-11 (2011) norm classifies the quality of wood surface pieces after its mechanical processing. Although this classification is difficult to achieve visually, the use of some tools, such as solid state laser, can facilitate this classification. The aim of this work was to evaluate the use of sunset laser to qualify mechanically processed surfaces with similar visual qualities. We used a log from the base of a Khaya ivorensis tree and one from a K. senegalensis tree, both 11 years old. 22 specimens of dimensions 600x140x30 mm (CxLxE) were made of each species. The specimens were flattened with speeds of 2400, 3600 and 4000 min-1 and advanced speeds were predetermined in 6 and 15 m.min-1. Then the samples were illuminated with sunset laser and photographed at high resolution, the images were transferred to the software Image J. To evaluate the sunset laser, areas of defects in wood that are classified as regular and bad by ASTM D 1666-11 (2011) were used. There was a difference in classification of wood defects between the two methods used, from the 31 specimens classified as regularly by visual analysis, 8 of them were classified as bad by the laser method. The use of solid-state laser in the sunset laser technique was more efficient in evaluating small differences in mechanically processed wood defects compared to visual evaluation.

Evaluation of the influence of laser in live biological materials

Some of the special characteristics of the laser associated with optical phenomena allows a series of applications in the biological area, based on the well-known phenomenon biospeckle. The technique of biospeckle has been developed as a tool for analysis of biological materials activity for the checking of moisture, level of activity, presence of parasites, among other attributes. Although the monitoring occurs by illuminating the material with a source of low power laser, the influence of the light on up the specimens biological activity becomes always a variable to be investigated. This work had as its objective to evaluation the influence the laser in the analysis of the biological activity measured by the biospeckle of a vegetal tissue; in this case a leaf of coffee plant, using the illumination time as parameter. Two ways of illumination had been used, the first one being reflecting only the laser on the leaf; and the second one the laser reflecting with a source of non-coherent light illuminating the environment. From the experimental results, it was verified that the data of the activity did not have any significant influence with the incidence of the laser, as well as of the non-coherent light throughout the time.

When noise became information: State-of-the-art in biospeckle laser

Laser was presented to science and industry in the 1960s and shortly became a useful tool in many areas, with applications based on its multiple characteristics such as coherence of light, which presents a phenomenon known as interference pattern, or speckle, when beam returns from an illuminated surface. Despite great application of speckle pattern, its residual presence, for example, in interferometric approaches was considered as a noise, demanding filtering. However, grains themselves became information as their dynamic changes in time started to be linked to biological sample activity. Dynamic laser speckle has been since then a phenomenon widely used to monitor biological activities in many areas from agriculture to medicine. It is known as biospeckle laser (BSL) when adopted in biological material, with high sensitivity to follow very tiny movements in biological tissues, linked to changes in speckle provided by scatterer activities inside and outside cells. Since the 1970s, biospeckle laser usage follows a crescent technologic spiral where technological developments opened room for new applications, while new demands regarding biological monitoring forced the development of new methodologies. Therefore, potential adoption of the phenomenon as a sensor, for instance, in agricultural and medical processes, as well as constant offer of new devices provided new turns in the BSL technologic spiral and opened room for technique improvement. In this study, I present a short history of biospeckle laser (BSL) with applications and development associated with challenges regarding its usage in portable and accessible devices or even in commercial equipment. And the history was packed in a temporal diagram identifying the breakpoints responsible for improvements in the use of the technique.