L’objectif du présent travail est d’étudier expérimentalement et numériquement la fissuration des bois tropicaux issus de la forêt gabonaise, à savoir : le Milicia excelsa (iroko),l’ Aucoumea klaineana pierre (okoumé) et Pterocarpus soyauxii (padouk). Cette étude est axée sur le processus de croissance de la fissure en mode d’ouverture et en mode mixte des trois essences à l’aide d’éprouvettes Compact Tension Shear (CTS) et Mixed Mode CrackGrowth (MMCG) modifiées. Les éprouvettes sont montées dans un système Arcan et placées dans une machine d’essai électromécanique. La méthode de la grille est utilisée pour mesurer les champs de déplacements et de déformations au voisinage de la fissure. Ces cartes ainsi obtenues permettent d’obtenir l’ouverture et la longueur de la fissure tout au long de l’essai. Les courbes force en fonction de l’ouverture de la fissure sont déduites des mesures. La méthode de la complaisance à déplacement imposé est utilisée pour calculer le taux de restitution d’énergie G en mode d’ouverture de fissure et en mode mixte. Les résultats ont montré un effet de l’épaisseur sur la fissuration. Ces résultats ont aussi permis de mettre en évidence une proportionnalité de la densité par rapport aux paramètres de rupture de ces essences. En mode mixte les valeurs de l’évolution de G sont présentées en fonction de la longueur de fissure après découplage des modes (séparation du mode 1 et du mode 2). On observe pour l’okoumé par exemple, que les rapports des taux de restitution d’énergie des deux modes sont constants, ce qui justifie le caractère intrinsèque des paramètres de fissuration obtenus. Des comparaisons faites avec les résultats issus de de la littérature sur les essences tempérées de même densité ont montré des similitudes. / The objective of the present work is to study experimentally and numerically the crackingbehavior of tropical woods from the Gabonese forest, namely : Milicia excelsa (iroko), Aucoumeaklaineana pierre (okume) and Pterocarpus soyauxii (padouk). This study focuseson the crack growth process in crack opening mode and mixed mode of these three speciesusing Modified Tension Shear (CTS) and Mixed Mode Crack Growth (MMCG) specimens.The specimens are mounted in an Arcan system and placed in an electromechanical testingmachine. The grid method is used to measure the displacement and strains fields near the tipcrack. These maps make it possible to obtain the opening and the length of the crack duringthe tests. The curves force showing the face as a function of the crack opening are deducedfrom the measurements. The experimental critical energy release rate G is evaluated by thecompliance method in imposed displacement. The results show an effect of the thickness oncracking. These results also made it possible to demonstrate a proportionality of the densitywith the parameters of rupture of these species. In mixed mode, after decoupling the modes(separation of mode 1 and mode 2), the values of G are presented as a function of to the cracklength. For Okume, for example, it was observed that the ratios of the energy release ratesof the two modes are constant, which justifies the intrinsic character of the cracking parameterswere obtained. Comparisons made with results from the literature review on temperatespecies of the same density showed similarities.

Due to its larger surface area and ease of preparation, pig esophageal mucosa has emerged as a practical and viable alternative to buccal mucosa for studying permeability characteristics in vitro. However, the permeation results in biological membranes have shown high variability due to inter-specimen and intra-specimen variations. These biological variables can significantly influence the drug permeation across porcine esophageal mucosa. Therefore, this study aimed to investigate the viability associated with drug permeation by examining four to five porcine specimens (inter-specimen variations) and different regions of the esophageal mucosa within the same pig (intra-specimen variation). The analysis revealed that inter-specimen variation was more pronounced in the lipophilic model diffusant hydrocortisone, compared to the hydrophilic diffusant caffeine. Both model diffusants exhibited a linear increase in permeability from the upper esophageal sphincter (UES) to the lower esophageal sphincter (LES). Notably, the permeability of LES was 1.7-fold greater for caffeine and 2.5-fold greater for hydrocortisone compared to UES. The histological examination revealed that the epithelial thickness of UES was greater than the LES. Additionally, the lag time of both model diffusants decreased linearly from UES to LES. Based on these results, it could be concluded that intra-specimen variation is highly pronounced for hydrocortisone than caffeine. These findings contribute to the advancement of research in drug permeation studies, emphasizing the importance of carefully considering both inter-specimen variation and intra-specimen variation when utilizing porcine esophageal mucosa as an ex vivo model to human buccal mucosa.

The diploma thesis deals with the determination of the influence of size, shape and type of test specimen on values of modulus of elasticity of light-weight concrete. A lot of different specimens were prepared from two concrete’s mixtures for the experiment. Tests for measurement of static modulus of elasticity and dynamic modulus of elasticity by ultrasonic impulse velocity method were made. The results were assessed and summarized in tabular and graphical form.

Background Venous blood tests constitute an important part in the diagnosis and treatment of patients. However, test results are often viewed as objective values rather than the end result of a complex process. This has clinical importance since most errors arise before the sample reaches the laboratory. Such preanalytical errors affect patient safety and are often due to human mistakes in the collection and handling of the sample. The preanalytical performance of venous blood testing in primary health care, where the majority of the patients contact with care occurs, has not previously been reported. Aims To investigate venous blood sampling practices and the prevalence of haemolysed blood samples in primary health care. Methods A questionnaire investigated the collection and handling of venous blood samples in primary health care centres in two county councils and in two hospital clinical laboratories. Haemolysis index was used to evaluate the prevalence of haemolysed blood samples sent from primary health care centres, nursing homes and a hospital emergency department. Results and discussion The results indicate that recommended preanalytical procedures were not always followed in the surveyed primary health care centres. For example, only 54% reported to always use name and Swedish identification number, and 5% to use photo-ID, the two recommended means for patient identification. Only 12% reported to always label the test tubes prior to blood collection. This increases the possibility of sample mix-up. As few as 6% reported to always allow the patient to rest at least 15 minutes before blood collection, desirable for a correct test result. Only 31% reported to have filed an incident report regarding venous blood sampling, indicating underreporting of incidents in the preanalytical phase. Major differences in the prevalence of haemolysed blood samples were found. For example, samples collected in the primary health care centre with the highest prevalence of haemolysed samples were six times (95% CI 4.0 to 9.2) more often haemolysed compared to the centre with the lowest prevalence. The significant variation in haemolysed samples is likely to reflect varying preanalytical conditions. Conclusions This thesis indicates that the preanalytical procedure in primary health care is associated with an increased risk of errors with consequences for patient safety and care. Monitoring of haemolysis index could be a valuable tool for estimating preanalytical sample quality. Further studies and interventions aimed at the preanalytical phase in primary health care are clearly needed.

<p>The work material in metal working operations always showssome kind of anisotropy. In order to simplify the theoreticalanalysis, especially considering bulk deformation processes,anisotropy is usually neglected and the material is assumed tobe isotropic. On the other hand, the analysis that consideredthe influence of anisotropy seldom incorporates the influenceof friction. For predicting the material flow during plasticdeformation and for predicting the final material properties ofthe product, adequate descriptions of both flow stress curvesand coefficients of friction have to be developed.</p><p>In the present work a number of experimental methods fordetermining the anisotropy have been utilized and compared:Yield loci, strain ratios (R-values) and establishing flowstress-curves in different directions. The results show thatthe yield loci measurements are weak in predicting anisotropywhen the material strain hardening is different in differentdirections. It is concluded that also the strain ration(R-value) measurements are unreliable for describinganisotropy. The most trustable and useful results were foundfrom multi-direction determinations of the flow stresses.</p><p>Three typical cases of ring upsetting conditions wereanalyzed by theory (3D-FEM) and experiments:</p><p>    An anisotropic ring, oriented 900 to the axis ofrotational symmetrical anisotropy. The friction coefficientwas the same in all directions</p><p>    An isotropic ring. The friction coefficient was differentin different directions</p><p>    An anisotropic ring oriented 00 to the axis of rotationalsymmetrical anisotropy. The friction coefficient was the samein all directions</p><p>The cases 1) and 2) reveal that the influence of anisotropyon the ring deformation is quite similar to that obtained bychanging the frictional condition. The case 3) exposes that ifthe material flow caused by anisotropy is incorrectly referredto friction, the possible error of the friction coefficient canbe as high as 80% for a pronounced anisotropic material. Amodified two-specimen method (MTSM) has been establishedaccording to an inverse method. Experiments were carried ascylinder upsetting. Here both ordinary cylinders were used aswell as so-called Rastegaev specimen. Also plane straincompression tests were utilized. The results show that MTSM isable to evaluate the validity of a selected mathematical modelwhen both the friction coefficient and the flow stress areunknown for a certain process. MTSM can also be used toestimate the friction coefficient and flow stress provided thatthe selected mathematical model is adequate.</p><p><b>Key words:</b>Anisotropy, friction coefficient, flowstress, modified two-specimen method and FE-analysis</p>

Titanium (Ti) alloys have been commonly used in the aerospace industry, not only because they have a high strength-to-weight ratio (comparing to the steels) but also their satisfactory corrosion resistance. Furthermore, they can be assembled with the carbon fibre composite parts. However, conventional manufacturing methods cause high material scrap rate and require lots of machining to obtain the final shape and size, which increases both the manufacturing time and cost. In order to improve the efficiency and reduce the cost of Ti parts, Additive Manufacturing (AM) has been developed. Rolled Wire and Arc Additive Manufacturing (rolled WAAM) is one of the AM processes. The main characteristics of this technology is the reduced β grain size to refine the alloy's microstructure. Both the ultimate tensile strength and yield strength of Ti alloy made by rolled WAAM are at least 10% higher than traditional wrought Ti. This project is to investigate the fatigue crack growth rates of the Ti-6Al-4V built by rolled WAAM process in both the longitudinal and transverse orientations to study the effect of rolling on fatigue crack growth rate of WAAM processed Ti. The project was carried out by testing the fatigue crack growth rates for 4 compact tension specimens. The test results of different orientations were compared with each other, and scatters in fatigue life and fatigue crack growth rate were found. Fatigue crack growth rate is lower in the longitudinal specimens. The results are also compared with those of the unrolled WAAM specimens tested in a previous project. It was found that rolling can significantly improve the fatigue crack growth behaviour in WAAM processed Ti, and can reduce the difference between the two orientations, i.e. achieving better isotropic material properties. Recorded scatters may be caused by the process induced residual stresses, error in measurement, and the test machine load range being much higher than the applied loads. More specimens can be tested to validate above observations further.

Este estudo teve como proposta analisar a efetividade e a influência de diferentes métodos de descontaminação e armazenamento de dentes humanos, visando à manutenção de suas propriedades e integridade estrutural. A amostra foi constituída por 126 molares hígidos recém-extraídos, cedidos ao Banco de Dentes Humanos da FOB-USP, que foram distribuídos de forma randômica em 4 grupos de acordo com o método de processamento empregado: controle - água destilada, timol a 0,1%, azida de sódio a 0,02% e autoclave. Foram realizados testes microbiológicos (07, 15 e 30 dias), de fluorescência a laser e de microdureza de superfície (0, 15 e 30 dias). A análise do teste microbiológico foi realizada de modo qualitativo (presença ou ausência de crescimento bacteriano) e quantitativo (frequências absolutas e relativas), enquanto nos testes de fluorescência a laser e microdureza de superfície houve a aplicação de Análise de Variância e teste de Tukey (p<0,05). Na análise microbiológica a autoclave foi o único método capaz de inibir o crescimento bacteriano, em todos os períodos. No teste de fluorescência a laser a solução de timol a 0,1% se mostrou mais viável na manutenção da integridade do órgão dentário, uma vez que não apresentou variações significativas nos valores de fluorescência a laser entre os tempos analisados (p>0,05). A análise de microdureza de superfície evidenciou a perda de estrutura dentária em todos os métodos utilizados, sendo que a azida de sódio permitiu uma menor perda de tecido dentário, entretanto este método promoveu perda de estrutura dentária nos espécimes entre o tempo 0 e 15 dias (de 440,20±19,75, para 247,40±21,09), e reendurecimento da superfície dentária entre o tempo 15 e 30 dias (276,93±13,37). Dentre os métodos de processamento analisados nenhum foi capaz de aliar a efetividade na descontaminação e no armazenamento com a manutenção da integridade estrutural dos órgãos dentários. / This study aimed to analyze the effectiveness and the influence of different methods of decontamination and storage of human teeth, in order to maintain their properties and structural integrity. The sample consisted of 126 recently extracted molars, assigned to the Human Teeth Bank of Bauru Dental School-University of São Paulo, which were distributed randomly into four groups according to the method of processing employed: control - distilled water, thymol 0.1%, sodium azide 0.02% and autoclave. The tests performed were Microbiological tests (7, 15 and 30 days), laser fluorescence and surface microhardness (0, 15 and 30 days). The analysis of microbiological test was performed qualitatively (presence or absence of bacterial growth) and quantitatively (absolute and relative frequencies), while on tests of laser fluorescence and surface microhardness were applied ANOVA and Tukey test (p <0.05). In the microbiological analysis the autoclave was the only method able to inhibit bacterial growth in all periods. In the laser fluorescence test thymol solution at 0.1% proved to be more viable in maintaining the integrity of the dental organ, since it did not show significant variations in the laser fluorescence values among the analyzed periods (p> 0.05). The surface microhardness analysis showed the tooth structure loss in all methods used, and sodium azide led to a smaller tooth tissue loss, however this method promoted the tooth structure loss in the specimens between 0 and 15 days (of 440.20 ± 19.75 to 247.40 ± 21.09), and the hardened tooth surface between 15 and 30 days (276.93 ± 13.37). Among the processing methods analyzed none was able to combine the effectiveness in the decontamination and storage with the maintenance of the structural integrity of the dental organs.

Este estudo teve como proposta analisar a efetividade e a influência de diferentes métodos de descontaminação e armazenamento de dentes humanos, visando à manutenção de suas propriedades e integridade estrutural. A amostra foi constituída por 126 molares hígidos recém-extraídos, cedidos ao Banco de Dentes Humanos da FOB-USP, que foram distribuídos de forma randômica em 4 grupos de acordo com o método de processamento empregado: controle - água destilada, timol a 0,1%, azida de sódio a 0,02% e autoclave. Foram realizados testes microbiológicos (07, 15 e 30 dias), de fluorescência a laser e de microdureza de superfície (0, 15 e 30 dias). A análise do teste microbiológico foi realizada de modo qualitativo (presença ou ausência de crescimento bacteriano) e quantitativo (frequências absolutas e relativas), enquanto nos testes de fluorescência a laser e microdureza de superfície houve a aplicação de Análise de Variância e teste de Tukey (p<0,05). Na análise microbiológica a autoclave foi o único método capaz de inibir o crescimento bacteriano, em todos os períodos. No teste de fluorescência a laser a solução de timol a 0,1% se mostrou mais viável na manutenção da integridade do órgão dentário, uma vez que não apresentou variações significativas nos valores de fluorescência a laser entre os tempos analisados (p>0,05). A análise de microdureza de superfície evidenciou a perda de estrutura dentária em todos os métodos utilizados, sendo que a azida de sódio permitiu uma menor perda de tecido dentário, entretanto este método promoveu perda de estrutura dentária nos espécimes entre o tempo 0 e 15 dias (de 440,20±19,75, para 247,40±21,09), e reendurecimento da superfície dentária entre o tempo 15 e 30 dias (276,93±13,37). Dentre os métodos de processamento analisados nenhum foi capaz de aliar a efetividade na descontaminação e no armazenamento com a manutenção da integridade estrutural dos órgãos dentários. / This study aimed to analyze the effectiveness and the influence of different methods of decontamination and storage of human teeth, in order to maintain their properties and structural integrity. The sample consisted of 126 recently extracted molars, assigned to the Human Teeth Bank of Bauru Dental School-University of São Paulo, which were distributed randomly into four groups according to the method of processing employed: control - distilled water, thymol 0.1%, sodium azide 0.02% and autoclave. The tests performed were Microbiological tests (7, 15 and 30 days), laser fluorescence and surface microhardness (0, 15 and 30 days). The analysis of microbiological test was performed qualitatively (presence or absence of bacterial growth) and quantitatively (absolute and relative frequencies), while on tests of laser fluorescence and surface microhardness were applied ANOVA and Tukey test (p <0.05). In the microbiological analysis the autoclave was the only method able to inhibit bacterial growth in all periods. In the laser fluorescence test thymol solution at 0.1% proved to be more viable in maintaining the integrity of the dental organ, since it did not show significant variations in the laser fluorescence values among the analyzed periods (p> 0.05). The surface microhardness analysis showed the tooth structure loss in all methods used, and sodium azide led to a smaller tooth tissue loss, however this method promoted the tooth structure loss in the specimens between 0 and 15 days (of 440.20 ± 19.75 to 247.40 ± 21.09), and the hardened tooth surface between 15 and 30 days (276.93 ± 13.37). Among the processing methods analyzed none was able to combine the effectiveness in the decontamination and storage with the maintenance of the structural integrity of the dental organs.

Métodos acurados de avaliação de tenacidade à fratura, incluindo curvas de resistência ao rasgamento dúctil de juntas soldadas de dutos e risers rígidos, tornam-se essenciais em procedimentos de avaliação de defeitos em regiões de soldas e zonas termicamente afetadas, nas quais defeitos não detectados podem se propagar devido às grandes tensões e deformações envolvidas na instalação e/ou operação dessa classe de estruturas. Este trabalho apresenta uma investigação experimental da tenacidade à fratura de uma junta soldada de um duto rígido de aço API 5L X80 (curvas J-Ãa). A motivação para este trabalho decorre da demanda crescente na aplicação de dutos de alta resistência na indústria de óleo e gás, em particular dutos submarinos e risers rígidos em catenária. Para tal, foram empregados corpos de prova de tração SE(T) fixados por garras, e flexão três pontos SE(B) contendo entalhe no centro da solda, para determinação das curvas J-R pelo método do corpo de prova único utilizando a técnica da flexibilidade no descarregamento, além das funções de flexibilidade e fatores n referentes aos corpos de prova SE(T) e SE(B) em função do nível de dissimilaridades mecânicas, o que permite obter valores mais assertivos das propriedades de tenacidade à fratura de juntas soldadas. / Accurate measurements of fracture resistance properties, including crack growth resistance curves for pipeline girth welds, become essential in defect assessment procedures of the weldment region and the heat affected zone, where undetected crack-like defects (such as lack of penetration, deep undercuts, root cracks, etc.) may exhibit further crack extension due to high tensile stresses and strains during installation and in-service operation. This work presents an investigation of the ductile tearing properties for a girth weld made of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves (J-Ãa curves). Use of these materials is motivated by the increasing demand in the number of applications for manufacturing high strength pipes for the oil and gas industry including marine applications and steel catenary risers. Testing of the pipeline girth welds utilized sidegrooved, clamped SE(T) specimens and 3P bend SE(B) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using a single specimen technique. Recently developed compliance functions and n-factors applicable for SE(T) and SE(B) fracture specimens with homogeneous material and overmatch welds are introduced to determine crack growth resistance data from laboratory measurements of load-displacement records. This experimental characterization provides additional toughness data which serve to evaluate crack growth resistance properties of pipeline girth welds using SE(T) and SE(B) specimens with weld centerline cracks.

Through sculpture and drawing, I create my own versions of natural specimens primarily based upon the visual unity of disparate organisms. Invented specimens are composed using a variety of processes employing a mixture of atypical materials following the (20th, 21st century) Postmodern shift away from formalist and traditional uses of any singular medium. As well as a variety of art materials, the specimens are hybrids of organic and biomorphic elements, blurring boundaries between botanical, animal, fungal, metal, and mineral. Is my approach perhaps like Charles Darwin, observant and studious naturalist, or am I more like Dr. Frankenstein, science fiction maker of monstrosities?