Lifetime prediction of self-healing ceramic-matrix composites using a multi-physics image-based model

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Blood chemistry of medium-growing male and female chickens supplemented black soldier fly live larvae

Effects of live larvae provision on poultry chemical blood parameters have been poorly investigated. This study aims to evaluate the changes in blood chemistry parameters in medium-growing chickens supplemented black soldier fly (BSF) live larvae. Two hundred and forty 21d old sexed Label Naked Neck birds were divided into 4 experimental groups: females fed basal organic feed (BOF), males fed BOF, females fed BOF + 10% BSF live larvae supplementation based on the expected daily feed intake (DFI) and males fed BOF + 10% BSF live larvae supplementation based on the DFI (6 replicates/diet, 10 birds/replicate). Blood samples were collected at slaughter (82d old) from 2 birds/pen (12 birds/treatment). Serum samples were used for biochemical analysis. A compact liquid chemistry analyzer system (BT 1500 vet–Futurlab) was used to determine the concentrations of alanine aminotransferase (U/I), aspartate aminotransferase (U/I), creatinine total proteins (mg/dl), uric acid (mg/dl), cholesterol (mg/dl), triglycerides (mg/dl), gamma glutamyltransferase (GGT, U/I), phosphorus (mg/dl) and magnesium (mg/dl). Data were analyzed by GLMM (SPSS software, P<0.05). Overall, the blood parameters were not affected by the live larvae supplementation (P>0.05) in both sexes, thus being indicative of a good health status of the birds. Moreover, the GGT was detected in lower concentrations in the supplemented groups than in the control groups (P<0.05), suggesting a positive effect on the hepatic function. In conclusion, the live BSF larvae provision did not negatively affect the blood parameters of medium-growing chickens and could be beneficial for bird hepatic activity

Blood chemistry of medium-growing male and female chickens supplemented black soldier fly live larvae

Effects of live larvae provision on poultry chemical blood parameters have been poorly investigated. This study aims to evaluate the changes in blood chemistry parameters in medium-growing chickens supplemented black soldier fly (BSF) live larvae. Two hundred and forty 21d old sexed Label Naked Neck birds were divided into 4 experimental groups: females fed basal organic feed (BOF), males fed BOF, females fed BOF + 10% BSF live larvae supplementation based on the expected daily feed intake (DFI) and males fed BOF + 10% BSF live larvae supplementation based on the DFI (6 replicates/diet, 10 birds/replicate). Blood samples were collected at slaughter (82d old) from 2 birds/pen (12 birds/treatment). Serum samples were used for biochemical analysis. A compact liquid chemistry analyzer system (BT 1500 vet–Futurlab) was used to determine the concentrations of alanine aminotransferase (U/I), aspartate aminotransferase (U/I), creatinine total proteins (mg/dl), uric acid (mg/dl), cholesterol (mg/dl), triglycerides (mg/dl), gamma glutamyltransferase (GGT, U/I), phosphorus (mg/dl) and magnesium (mg/dl). Data were analyzed by GLMM (SPSS software, P<0.05). Overall, the blood parameters were not affected by the live larvae supplementation (P>0.05) in both sexes, thus being indicative of a good health status of the birds. Moreover, the GGT was detected in lower concentrations in the supplemented groups than in the control groups (P<0.05), suggesting a positive effect on the hepatic function. In conclusion, the live BSF larvae provision did not negatively affect the blood parameters of medium-growing chickens and could be beneficial for bird hepatic activity

Modélisation multiphysique basée images, évaluation de la durée de vie et analyse des scénarios de rupture des mini-composites à matrice céramique auto-cicatrisante sous tension

This thesis aims to develop a model capable of describing the self-healing behaviour of ceramic matrix composites considered for use in hot parts of aircraft turbines and to investigate the effect of complex physical, chemical and mechanical interactions in terms of lifetime. The interest in these materials is due to their extremely long lifetime due to their ability to heal cracks by the action of a protective oxide. The first part of the thesis is devoted to the description of the numerical model built to characterize the behaviour and failure of a mini-composite under a tensile load proceeding from a two-dimensional image-based model of a transverse crack. A system of crack-averaged PDEs and ODEs is proposed for the transport of oxygen and of all the chemical species involved in the healing process. The dimensionless form of the equations is studied to perform the most appropriate discretization choices concerning time integration and boundary conditions. Concerning the fibres’ degradation, a slow crack growth model explicitly dependent on the environmental parameters is calibrated using a particular exact solution involving constant external parameters and integrated numerically in the general case. The tow failure results from the statistical distribution of the fibres’ initial strength, the slow crack growth kinetics, and the load transfer following fibres breakage. The latter is described via an analytical mechanical model. The lifetime prediction capabilities of the resulting multi-physics numerical model, as well as the impact of temperature, applied load, spatial variation of the statistical distribution of fibres strength and tow's shape and size are investigated in the second part of the thesis. Moreover, to examine the degree of the related variability of the evaluated lifetime shown by the results, an uncertainty quantification study together with a sensitivity analysis of our model are proposed to ensure the model stability and describe accurately how the uncertainty of the input parameters can be propagated throughout the simulations.La présente thèse se propose de développer un modèle capable de décrire le comportement auto-cicatrisant des composites à matrice céramique destinés à être utilisés dans les parties chaudes des turbines d'avion et d'étudier l'effet des complexes interactions physiques, chimiques et mécaniques en termes de durée de vie. L'intérêt pour ces matériaux est dû à leur durée de vie extrêmement élevée en raison de leur capacité à cicatriser les fissures par l'action d'un oxyde protecteur. La première partie de la thèse est consacrée à la description du modèle numérique construit pour caractériser le comportement et la rupture d'un mini-composite sous une charge de traction à partir d'un modèle image bidimensionnel d'une fissure transversale. Un système d'EDP et d'ODEs moyenné sur une fissure est proposé pour le transport de l'oxygène et de toutes les espèces chimiques impliquées dans le processus de cicatrisation. La forme adimensionnelle des équations est étudiée pour effectuer les choix de discrétisation les plus appropriés concernant l'intégration temporelle et les conditions aux limites. Concernant la dégradation des fibres, un modèle de propagation sous critique des défauts explicitement dépendant des paramètres environnementaux est calibré en utilisant une solution exacte particulière impliquant des paramètres externes constants et intégré numériquement dans le cas général. La rupture du fil résulte de la distribution statistique de la résistance initiale des fibres, de la cinétique de croissance progressive des défauts et du mécanisme de répartition de la charge suite à la rupture des fibres. Ce processus est décrit par un modèle mécanique analytique. Les capacités de prédiction de la durée de vie du modèle numérique multi-physique résultant, ainsi que l'impact de la température, de la charge appliquée, de la variation spatiale de la distribution statistique de la résistance des fibres et de la forme et de la taille de fil sont étudiés dans la deuxième partie de la thèse. Enfin, pour examiner le degré de variabilité de la durée de vie évaluée, une étude de quantification des incertitudes ainsi qu'une analyse de sensibilité de ce modèle sont proposées afin d'assurer sa stabilité et de décrire précisément comment l'incertitude des paramètres d'entrée se propage par la simulation

Modélisation multiphysique basée images, évaluation de la durée de vie et analyse des scénarios de rupture des mini-composites à matrice céramique auto-cicatrisante sous tension

La présente thèse se propose de développer un modèle capable de décrire le comportement auto-cicatrisant des composites à matrice céramique destinés à être utilisés dans les parties chaudes des turbines d'avion et d'étudier l'effet des complexes interactions physiques, chimiques et mécaniques en termes de durée de vie. L'intérêt pour ces matériaux est dû à leur durée de vie extrêmement élevée en raison de leur capacité à cicatriser les fissures par l'action d'un oxyde protecteur. La première partie de la thèse est consacrée à la description du modèle numérique construit pour caractériser le comportement et la rupture d'un mini-composite sous une charge de traction à partir d'un modèle image bidimensionnel d'une fissure transversale. Un système d'EDP et d'ODEs moyenné sur une fissure est proposé pour le transport de l'oxygène et de toutes les espèces chimiques impliquées dans le processus de cicatrisation. La forme adimensionnelle des équations est étudiée pour effectuer les choix de discrétisation les plus appropriés concernant l'intégration temporelle et les conditions aux limites. Concernant la dégradation des fibres, un modèle de propagation sous critique des défauts explicitement dépendant des paramètres environnementaux est calibré en utilisant une solution exacte particulière impliquant des paramètres externes constants et intégré numériquement dans le cas général. La rupture du fil résulte de la distribution statistique de la résistance initiale des fibres, de la cinétique de croissance progressive des défauts et du mécanisme de répartition de la charge suite à la rupture des fibres. Ce processus est décrit par un modèle mécanique analytique. Les capacités de prédiction de la durée de vie du modèle numérique multi-physique résultant, ainsi que l'impact de la température, de la charge appliquée, de la variation spatiale de la distribution statistique de la résistance des fibres et de la forme et de la taille de fil sont étudiés dans la deuxième partie de la thèse. Enfin, pour examiner le degré de variabilité de la durée de vie évaluée, une étude de quantification des incertitudes ainsi qu'une analyse de sensibilité de ce modèle sont proposées afin d'assurer sa stabilité et de décrire précisément comment l'incertitude des paramètres d'entrée se propage par la simulation.This thesis aims to develop a model capable of describing the self-healing behaviour of ceramic matrix composites considered for use in hot parts of aircraft turbines and to investigate the effect of complex physical, chemical and mechanical interactions in terms of lifetime. The interest in these materials is due to their extremely long lifetime due to their ability to heal cracks by the action of a protective oxide. The first part of the thesis is devoted to the description of the numerical model built to characterize the behaviour and failure of a mini-composite under a tensile load proceeding from a two-dimensional image-based model of a transverse crack. A system of crack-averaged PDEs and ODEs is proposed for the transport of oxygen and of all the chemical species involved in the healing process. The dimensionless form of the equations is studied to perform the most appropriate discretization choices concerning time integration and boundary conditions. Concerning the fibres’ degradation, a slow crack growth model explicitly dependent on the environmental parameters is calibrated using a particular exact solution involving constant external parameters and integrated numerically in the general case. The tow failure results from the statistical distribution of the fibres’ initial strength, the slow crack growth kinetics, and the load transfer following fibres breakage. The latter is described via an analytical mechanical model. The lifetime prediction capabilities of the resulting multi-physics numerical model, as well as the impact of temperature, applied load, spatial variation of the statistical distribution of fibres strength and tow's shape and size are investigated in the second part of the thesis. Moreover, to examine the degree of the related variability of the evaluated lifetime shown by the results, an uncertainty quantification study together with a sensitivity analysis of our model are proposed to ensure the model stability and describe accurately how the uncertainty of the input parameters can be propagated throughout the simulations

Modélisation multiphysique basée images, évaluation de la durée de vie et analyse des scénarios de rupture des mini-composites à matrice céramique auto-cicatrisante sous tension

This thesis aims to develop a model capable of describing the self-healing behaviour of ceramic matrix composites considered for use in hot parts of aircraft turbines and to investigate the effect of complex physical, chemical and mechanical interactions in terms of lifetime. The interest in these materials is due to their extremely long lifetime due to their ability to heal cracks by the action of a protective oxide. The first part of the thesis is devoted to the description of the numerical model built to characterize the behaviour and failure of a mini-composite under a tensile load proceeding from a two-dimensional image-based model of a transverse crack. A system of crack-averaged PDEs and ODEs is proposed for the transport of oxygen and of all the chemical species involved in the healing process. The dimensionless form of the equations is studied to perform the most appropriate discretization choices concerning time integration and boundary conditions. Concerning the fibres’ degradation, a slow crack growth model explicitly dependent on the environmental parameters is calibrated using a particular exact solution involving constant external parameters and integrated numerically in the general case. The tow failure results from the statistical distribution of the fibres’ initial strength, the slow crack growth kinetics, and the load transfer following fibres breakage. The latter is described via an analytical mechanical model. The lifetime prediction capabilities of the resulting multi-physics numerical model, as well as the impact of temperature, applied load, spatial variation of the statistical distribution of fibres strength and tow's shape and size are investigated in the second part of the thesis. Moreover, to examine the degree of the related variability of the evaluated lifetime shown by the results, an uncertainty quantification study together with a sensitivity analysis of our model are proposed to ensure the model stability and describe accurately how the uncertainty of the input parameters can be propagated throughout the simulations.La présente thèse se propose de développer un modèle capable de décrire le comportement auto-cicatrisant des composites à matrice céramique destinés à être utilisés dans les parties chaudes des turbines d'avion et d'étudier l'effet des complexes interactions physiques, chimiques et mécaniques en termes de durée de vie. L'intérêt pour ces matériaux est dû à leur durée de vie extrêmement élevée en raison de leur capacité à cicatriser les fissures par l'action d'un oxyde protecteur. La première partie de la thèse est consacrée à la description du modèle numérique construit pour caractériser le comportement et la rupture d'un mini-composite sous une charge de traction à partir d'un modèle image bidimensionnel d'une fissure transversale. Un système d'EDP et d'ODEs moyenné sur une fissure est proposé pour le transport de l'oxygène et de toutes les espèces chimiques impliquées dans le processus de cicatrisation. La forme adimensionnelle des équations est étudiée pour effectuer les choix de discrétisation les plus appropriés concernant l'intégration temporelle et les conditions aux limites. Concernant la dégradation des fibres, un modèle de propagation sous critique des défauts explicitement dépendant des paramètres environnementaux est calibré en utilisant une solution exacte particulière impliquant des paramètres externes constants et intégré numériquement dans le cas général. La rupture du fil résulte de la distribution statistique de la résistance initiale des fibres, de la cinétique de croissance progressive des défauts et du mécanisme de répartition de la charge suite à la rupture des fibres. Ce processus est décrit par un modèle mécanique analytique. Les capacités de prédiction de la durée de vie du modèle numérique multi-physique résultant, ainsi que l'impact de la température, de la charge appliquée, de la variation spatiale de la distribution statistique de la résistance des fibres et de la forme et de la taille de fil sont étudiés dans la deuxième partie de la thèse. Enfin, pour examiner le degré de variabilité de la durée de vie évaluée, une étude de quantification des incertitudes ainsi qu'une analyse de sensibilité de ce modèle sont proposées afin d'assurer sa stabilité et de décrire précisément comment l'incertitude des paramètres d'entrée se propage par la simulation

Overview on metamaterials for acoustic applications

The increasing requirement for bigger, faster and lighter vehicles has increased the demand of efficient structural arrangements, making sandwich constructions a well-established technique in lightweight component design. The weight reduction can be used to increase the payload, to increase the speed or just to reduce the energy consumption with maintained loading capability and/or max speed. However, lightweight design typically combines reduced weight and increased stiffness, leading to a deterioration of the noise and vibration attenuation performance. Consequently,merging lightweight and vibro-acoustic requirements results in a challenging and often conflicting task, for which novel low mass and compact volume solutions are sought. New ideas, coupled with the expanding technologies of computational simulation and additive manufacturing, will produce the next generation of materials. Metamaterial is just this: a new concept, a new technolgy which properties derive not from the nature of the material itself but by from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable to manipulate waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials. Metamaterial is a combination of ”meta” and ”material”. Meta is a Greek word which means something beyond, altered, changed. To the letter metamaterial means: material that does not exist in nature; in physics material with negative refractive index. Metamaterials found great interest in several applications for manipulating waves. First prototypes were built to manipulate electromagnetic waves at the end of the 19th century. Recently, metamaterials have found a great interest in vibro-acoustic field with favorable noise and vibration attenuation behavior, at least in some targeted and tunable frequency ranges, referred to as stop bands. Acoustic metamaterials (AMMs) are artificial structures made of subwavelength units such that their acoustic properties are new in comparison with that of the building units. Recent studies show that heterogeneous, poroelastic metamaterials can achieve considerable wave and/or vibration energy absorption. For instance, randomly embedding solid, metal inclusions into poroelastic foams improves the low frequency attenuation of the host media. Periodically distributing such inclusions also spawns bandgap phenomena to substantially increase low frequency vibroacoustic energy absorption via ”trapped” mode effects

Observational analysis on inflammatory reaction to talc pleurodesis: Small and large animal model series review

Talc pleurodesis has been associated with pleuropulmonary damage, particularly long-term damage due to its inert nature. The present model series review aimed to assess the safety of this procedure by examining inflammatory stimulus, biocompatibility and tissue reaction following talc pleurodesis. Talc slurry was performed in rabbits: 200 mg/kg checked at postoperative day 14 (five models), 200 mg/kg checked at postoperative day 28 (five models), 40 mg/kg, checked at postoperative day 14 (five models), 40 mg/kg checked at postoperative day 28 (five models). Talc poudrage was performed in pigs: 55 mg/kg checked at postoperative day 60 (18 models). Tissue inspection and data collection followed the surgical pathology approach currently used in clinical practice. As this was an observational study, no statistical analysis was performed. Regarding the rabbit model (Oryctolagus cunicoli), the extent of adhesions ranged between 0 and 30%, and between 0 and 10% following 14 and 28 days, respectively. No intraparenchymal granuloma was observed whereas, pleural granulomas were extensively encountered following both talc dosages, with more evidence of visceral pleura granulomas following 200 mg/kg compared with 40 mg/kg. Severe florid inflammation was observed in 2/10 cases following 40 mg/kg. Parathymic, pericardium granulomas and mediastinal lymphadenopathy were evidenced at 28 days. At 60 days, from rare adhesions to extended pleurodesis were observed in the pig model (Sus Scrofa domesticus). Pleural granulomas were ubiquitous on visceral and parietal pleurae. Severe spotted inflammation among the adhesions were recorded in 15/18 pigs. Intraparenchymal granulomas were observed in 9/18 lungs. Talc produced unpredictable pleurodesis in both animal models with enduring pleural inflammation whether it was performed via slurry or poudrage. Furthermore, talc appeared to have triggered extended pleural damage, intraparenchymal nodules (porcine poudrage) and mediastinal migration (rabbit slurry)