Aplicação de ensaios não destrutivos por correntes induzidas à caracterização de propriedades eléctricas de materiais processados no estado sólido

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção de Grau de Mestre em Engenharia Mecânica

Desenvolvimento e aplicação de ensaios não destrutivos para a indústria aeronáutica

Dissertação para obtenção do grau de mestre em Engenharia Mecânica

Eficiência da estabilização do solo e qualidade de tijolos prensados de terra crua tratada com aditivos químicos, avaliadas pela combinação de testes destrutivos e não-destrutivos

A qualidade de tijolos prensados de terra crua tratada quimicamente é influenciada basicamente pelo tipo de solo, adições químicas e período de cura. O presente trabalho teve como objetivo estudar a combinação de métodos destrutivos e não-destrutivos associados à análise estatística, para a avaliação da qualidade e da eficiência da estabilização de tijolos prensados de terra crua tratada com cimento, cal e silicato de sódio. Os teores de cimento e cal foram 0; 6 e 10%, e a dose de silicato de sódio foi de 4% em relação ao peso seco da mistura solo-aditivo. Após a sua moldagem, os tijolos foram submetidos à cura durante os períodos de 7; 28; 56 e 91 dias. As propriedades físico-mecânicas dos tijolos foram determinadas por meio de testes destrutivos, tais como a resistência à compressão simples e a absorção de água, e não-destrutivos por meio do ensaio acústico do ultra-som. Adotou-se o parâmetro "resistência anisotrópica" para simplificar as interpretações estatísticas. A adição química que conferiu a melhor qualidade técnica aos tijolos, foi a de 10% de cimento. O parâmetro resistência anisotrópica mostrou-se promissor com vistas à avaliação da qualidade técnica dos tijolos.

Um estudo das condições de percolação e estabilidade em barragens de terra mediante métodos geofísicos: caso do dique de Sant Llorenç de Montgai - Espanha

The monitoring of Earth dam makes use of visual inspection and instrumentation to identify and characterize the deterioration that compromises the security of earth dams and associated structures. The visual inspection is subjective and can lead to misinterpretation or omission of important information and, some problems are detected too late. The instrumentation are efficient but certain technical or operational issues can cause restrictions. Thereby, visual inspections and instrumentation can lead to a lack of information. Geophysics offers consolidated, low-cost methods that are non-invasive, non-destructive and low cost. They have a strong potential and can be used assisting instrumentation. In the case that a visual inspection and strumentation does not provide all the necessary information, geophysical methods would provide more complete and relevant information. In order to test these theories, geophysical acquisitions were performed using Georadar (GPR), Electric resistivity, Seismic refraction, and Refraction Microtremor (ReMi) on the dike of the dam in Sant Llorenç de Montgai, located in the province of Lleida, 145 km from Barcelona, Catalonia. The results confirmed that the geophysical methods used each responded satisfactorily to the conditions of the earth dike, the anomalies present and the geological features found, such as alluvium and carbonate and evaporite rocks. It has also been confirmed that these methods, when used in an integrated manner, are able to reduce the ambiguities in individual interpretations. They facilitate improved imaging of the interior dikes and of major geological features, thus inspecting the massif and its foundation. Consequently, the results obtained in this study demonstrated that these geophysical methods are sufficiently effective for inspecting earth dams and they are an important tool in the instrumentation and visual inspection of the security of the dams

Avaliação e implementação de métodos de estimação de tempo de atraso de sinais de ultra-som

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ensaios não-destrutivos de propagação de ondas em toras e madeira serrada de Pinus. taeda L.

In this paper it was evaluated the influence of the relative position of logs on the trees, the type of wood (juvenile and mature wood and pith) and the dimension of sawed wood elements on the velocity of propagation of stress waves into the material on condition. P. taeda L wood (43 years old trees) from Horto Florestal of Manduri (latitude 230 00’ south, longitude 400 19’ west and altitude de 700 m) São Paulo State, Brazil were used, considering its easy growth rings visualization and the better ju regions definition. Six trees were randomly chosen in the plantation. Trees were sawed into 4 logs (2,5 m long each. In each log it was delimited the central board (80mm tick) region and the lateral boards (25mm tick) regions, cons right hand. It were evaluated relation between velocity of stress waves on logs and the correspondent lumber (central and lateral boards), on green condition, on the three main region of the elements (mature wood results obtained revealed the concordance between velocities of stress waves in the material before and after the its mechanical processing. It was also revealed statistical differences between the velocity of stress waves at juvenile wood, mature wood and pith regions. Keywords: stress wave method, velocity 17 destrutivos de propagação da propagação de ondas de tensão em toras e madeira serrada de taeda L. Hernando Alfonso Lara Palma - Universidade Estadual Paulista Faculdade de Ciências Agronômicas – FCA/UNESP – Botucatu - SP, e-mail: awballarin@fca.unesp.br Luiz Antonio Vasques Hellmeister - Universidade Estadual Paulista - Faculdade de Arquitetura, FAAC/UNESP – Bauru - SP, e-mail: hellmeister@faac.unesp.br Este trabalho teve como objetivo analisar a influência do tipo de lenho, da posição da tora ao longo do fuste e das dimensões das peças desdobradas, na velocidade de as de tensão (Stress wave method), na condição de madeira verde. P. taeda L., originária de árvores de plantio do Horto Florestal de SP., com idade aproximada de 43 anos, pela facilidade de identificação dos anéis imento e demarcação das regiões de madeira adulta e madeira juvenil. Foram amostradas 6 árvores distintas, escolhidas ao acaso do talhão selecionado. De cada árvore foram retiradas 4 toras com comprimento de 2,5 m cada. Foram demarcadas nas toras a ha central (8 cm de espessura) e 4 tábuas laterais (espessura comercial de 2,5 cm), sendo duas à esquerda e duas à direita da prancha central. Foram avaliadas as relações existentes entre as velocidades de propagação das ondas de tensão na madeira íntegra (toras) e desdobrada (pranchas e tábuas), na condição de madeira verde, nas três regiões distintas do lenho: medula, madeira adulta e madeira juvenil. A análise comparativa dos resultados revelou a concordância entre as velocidades antes e após o desdobr madeira. Houve diferenciação estatisticamente significativa entre as velocidades de propagação das ondas de tensão nos lenhos adulto, juvenil e na medula. -destrutivos, método das ondas de tensão, Pinus taeda stress wave tests on green logs and lumber of Pinus taeda In this paper it was evaluated the influence of the relative position of logs on the trees, the type of wood (juvenile and mature wood and pith) and the dimension of sawed wood elements on the velocity of propagation of stress waves into the material on L wood (43 years old trees) from Horto Florestal of Manduri (latitude 19’ west and altitude de 700 m) São Paulo State, Brazil were used, considering its easy growth rings visualization and the better juvenile and mature wood regions definition. Six trees were randomly chosen in the plantation. Trees were sawed into 4 logs (2,5 m long each. In each log it was delimited the central board (80mm tick) region and the lateral boards (25mm tick) regions, considering 2 boards on the left and 2 at the right hand. It were evaluated relation between velocity of stress waves on logs and the correspondent lumber (central and lateral boards), on green condition, on the three main region of the elements (mature wood, juvenile wood and pith). Comparative analyses of results obtained revealed the concordance between velocities of stress waves in the material before and after the its mechanical processing. It was also revealed statistical differences ty of stress waves at juvenile wood, mature wood and pith regions

Espécies reativas de oxigênio e de nitrogênio, antioxidantes e marcadores de dano oxidativo em sangue humano: principais métodos analíticos para sua determinação

We review here the chemistry of reactive oxygen and nitrogen species, their biological sources and targets; particularly, biomolecules implicated in the redox balance of the human blood, and appraise the analytical methods available for their detection and quantification. Those biomolecules are represented by the enzymatic antioxidant defense machinery, whereas coadjutant reducing protection is provided by several low molecular weight molecules. Biomolecules can be injured by RONS yielding a large repertoire of oxidized products, some of which can be taken as biomarkers of oxidative damage. Their reliable determination is of utmost interest for their potentiality in diagnosis, prevention and treatment of maladies.

Aplicação de métodos de calibração multivariada para a determinação simultânea de riboflavina (VB2), tiamina (VB1), piridoxina (VB6) e nicotinamida (VPP)

In this work, the artificial neural networks (ANN) and partial least squares (PLS) regression were applied to UV spectral data for quantitative determination of thiamin hydrochloride (VB1), riboflavin phosphate (VB2), pyridoxine hydrochloride (VB6) and nicotinamide (VPP) in pharmaceutical samples. For calibration purposes, commercial samples in 0.2 mol L-1 acetate buffer (pH 4.0) were employed as standards. The concentration ranges used in the calibration step were: 0.1 - 7.5 mg L-1 for VB1, 0.1 - 3.0 mg L-1 for VB2, 0.1 - 3.0 mg L-1 for VB6 and 0.4 - 30.0 mg L-1 for VPP. From the results it is possible to verify that both methods can be successfully applied for these determinations. The similar error values were obtained by using neural network or PLS methods. The proposed methodology is simple, rapid and can be easily used in quality control laboratories.

Química forense: perspectivas sobre novos métodos analíticos aplicados à documentoscopia, balística e drogas de abuso

In this review recent methods developed and applied to solve criminal occurences related to documentoscopy, ballistic and drugs of abuse are discussed. In documentoscopy, aging of ink writings, the sequence of line crossings and counterfeiting of documents are aspects to be solved with reproducible, fast and non-destructive methods. In ballistic, the industries are currently producing ''lead-free'' or ''nontoxic'' handgun ammunitions, so new methods of gunshot residues characterization are being presented. For drugs analysis, easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is shown to provide a relatively simple and selective screening tool to distinguish m-CPP and amphetamines (MDMA) tablets, cocaine and LSD.

Métodos probabilístico e determinístico para diagnóstico da necessidade de subsolagem de solos agrícolas

This paper presents two techniques to evaluate soil mechanical resistance to penetration as an auxiliary method to help in a decision-making in subsoiling operations. The decision is based on the volume of soil mobilized as a function of the considered critical soil resistance to penetration in each case. The first method, probabilistic, uses statistical techniques to define the volume of soil to be mobilized. The other method, deterministic, determines the percentage of soil to be mobilized and its spatial distribution. Both cases plot the percentage curves of experimental data related to the soil mechanical resistance to penetration equal or larger to the established critical level and the volume of soil to be mobilized as a function of critical level. The deterministic method plots showed the spatial distribution of the data with resistance to penetration equal or large than the critical level. The comparison between mobilized soil curves as a function of critical level using both methods showed that they can be considered equivalent. The deterministic method has the advantage of showing the spatial distribution of the critical points.

Desempenho físico-mecânico de minipainéis de terra crua tratada com aditivos químicos

The aim of this research was to study the effect of chemical additives (lime and Portland cement) associated with sodium silicate on soil in order to obtain compressed soil bricks. Mini panels were constructed with such bricks being their physical and mechanical characteristics determined in laboratory conditions and their behavior evaluated through the association of destructive and non-destructive methods. For this purpose a sandy soil and a finely divided one were added to Portland cement and lime in the dosage of 6% and 10% taken in dry weight basis in relation to the dry soil. The sodium silicate dosage of 4% was also taken in dry weight basis in relation to the dry soil-cement or to the dry soil-lime. The compressed soil bricks were cured in a humidity chamber for 7; 28; 56 and 91 days. The bricks were laid on the fourteenth day to form prismatic mini panels each one with four layers of bricks. After 28; 56 and 91 days the mini panels were submitted to both; ultrasonic and compressive tests to determine its elastic properties (dynamic modulus) and the compressive resistance. The best results in terms of compressive strength, water absorption capacity or dynamic elastic modulus, were reached by the sandy soil added to 10% of Portland cement or lime associated with sodium silicate.

Análise de custo-efetividade de métodos preventivos para superfície oclusal de acordo com o risco de cárie: resultados de um ensaio clínico controlado

This study presents the results of a cost-effectiveness analysis in a controlled clinical trial on the effectiveness of a modified glass ionomer resin sealant ( Vitremer, 3M ESPE) and the application of fluoride varnish (Duraphat, Colgate) on occlusal surfaces of first permanent molars in children 6-8 years of age (N = 268), according to caries risk (high versus low). Children were examined semiannually by the same calibrated dentist for 24 months after allocation in six groups: high and low risk controls (oral health education every three months); high and low risk with varnish (oral health education every three months + varnish biannually); and high and low risk with sealant (oral health education every three months + a single application of sealant). Economic analysis showed that sealing permanent first molars of high-risk schoolchildren showed a C/E ratio of US$ 119.80 per saved occlusal surface and an incremental C/E ratio of US$ 108.36 per additional saved occlusal surface. The study concluded that sealing permanent first molars of high-risk schoolchildren was the most cost-effective intervention.

Estudo comparativo dos métodos de estimativa da idade óssea de Greulich & Pyle e Tanner & Whitehouse

The purpose of this study was to verify whether the Greulich & Pyle (GP), Greulich & Pyle Visual (GPV) and Tanner & Whitehouse (TW) methods for estimating skeletal age could be applied in the Brazilian population, and which of these three methods could be considered more reliable when compared with the chronological age of the individuals. This study was based on one hundred and sixty volunteers (80 females and 80 males) with ages between 6 years and 10 months and 14 years and 9 months. The results showed that for the GP method, the correlations with chronological age were 0.95 for males and 0.97 for females. For the GPV method, the correlations were 0.96 and 0.97, respectively and for TW, 0.96 and 0.97. The results showed that the Greulich & Pyle, Greulich & Pyle Visual and Tanner & Whitehouse methods presented high correlation values when compared with the chronological age of the individuals. Corrective factors were established to make these methods applicable to the Brazilian population.

Metamorfose planar via métodos Level Set e Particle Level Set para a reconstrução de superfícies tridimensionais

Evolving interfaces were initially focused on solutions to scientific problems in Fluid Dynamics. With the advent of the more robust modeling provided by Level Set method, their original boundaries of applicability were extended. Specifically to the Geometric Modeling area, works published until then, relating Level Set to tridimensional surface reconstruction, centered themselves on reconstruction from a data cloud dispersed in space; the approach based on parallel planar slices transversal to the object to be reconstructed is still incipient. Based on this fact, the present work proposes to analyse the feasibility of Level Set to tridimensional reconstruction, offering a methodology that simultaneously integrates the proved efficient ideas already published about such approximation and the proposals to process the inherent limitations of the method not satisfactorily treated yet, in particular the excessive smoothing of fine characteristics of contours evolving under Level Set. In relation to this, the application of the variant Particle Level Set is suggested as a solution, for its intrinsic proved capability to preserve mass of dynamic fronts. At the end, synthetic and real data sets are used to evaluate the presented tridimensional surface reconstruction methodology qualitatively.