Sclerostin, a protein coded for by the SOST gene, is an osteocyte-expressed negative regulator of bone formation. The absence of SOST in the genome may have an effect on bone formation both during skeletal maturation and full maturity. This study attempts to determine significant differences in the mechanical properties of bone that expresses SOST compared to bone that does not. One hundred femur samples from 6, 8, and 12 month old mice were obtained from Lawrence Livermore National Labs and loaded until failure using three-point bending. Results showed significant differences in treatment group effects for cross sectional area, yield force, and ultimate force. SOST knockout (KO) mice were found to have significantly higher values for these properties in comparison to transgenic (TG) and wildtype (WT) littermates. In addition, there was a noted effect dependent on the primary axis of loading, anterior-posterior versus medial-lateral. Lastly, data from this study support the existing hypothesis that there is no systematic side-to-side (left-right) difference in bone formation. This data may aid understanding of the role SOST has in bone formation. If the structural integrity and quality of bone resulting from the removal of the SOST gene is shown to be comparable to that of normal, healthy bone, the use of gene therapy to combat diseases/disorders such as osteoporosis may lead to important contributions to medical therapy.

Sandwich beams are composite systems having high stiffness-to-weight and strength-to-weight ratios and are used as light weight load bearing components. The use of thin, strong skin sheets adhered to thicker, lightweight core materials has allowed industry to build strong, stiff, light, and durable structures. Due to the use of viscoelastic polymer constituents, sandwich beams can exhibit time-dependent behavior. This study examines and predicts the time-dependent behavior of sandwich beams driven by the viscoelastic foam core. Governing equations of the deformation of viscoelastic materials are often represented in differential form or hereditary integral form. A single integral constitutive equation is used to model linear viscoelastic materials by means of the Boltzmann superposition principle. Based on the strength of materials approach, the analytical solution for the deformation in a viscoelastic sandwich beam is determined based on the application of the Correspondence Principle and Laplace transform. Finite element (FE) method is used to analyze the overall transient responses of the sandwich systems subject to a concentrated point load at the midspan of the beam. A 2D plane strain element is used to generate meshes of the three-point bending beam. User material (UMAT) subroutine in ABAQUS FE code is utilized to incorporate the viscoelastic constitutive model for the foam core. Analytical models and experimental data available in the literature are used to verify the results obtained from the FE analysis. The stress, strain, and deformation fields during creep responses are analyzed. Parameters such as the viscosity of the foam core, the ratio of the skin and core thicknesses, the ratio of the skin and core moduli, and adhesive layers are varied and their effect on the timedependent behavior of the sandwich system is examined.

The objective of this research is to determine how the sandwich's physical characteristics have an impact on the mechanical properties, determine under what conditions the specimens will be lighter and mechanically stronger, and determine if the use of an aluminum honeycomb sandwich as a construction material is feasible. The research has aimed at the use of aluminum sandwiches as light and strong material. The study of the structural layers' damage resistance and tolerance demonstrated that the top and bottom layers play a crucial role. The thesis presents three test results from aluminum honeycomb sandwich compression horizontal, compressive vertical, and bending tests. Also, each group was displayed mechanically and simulated in Abaqus. The study determines the mechanical properties such as maximum elastic stress-strain, ultimate stress-strain, fracture point, density, poison ration, young modulus, and maximum deflection was determined. The energy absorbed by the FEA, such modulus of elasticity, resilience, and toughness, the crack propagation, the test's view shows aluminum honeycomb behaved like a brittle material with both compression test. And the maximum deflection, crack propagation, shear forces, bending moment, and images illustrated that the layers play a crucial role in the 3-point bend test.

Presented in this work are the results of twelve flexural tests conducted on small-scale coupons to establish the load-deflection behavior of UNS S32003 (ATI 2003®) hot-rolled duplex stainless steel flat plates. All specimens were tested as simply supported beams loaded at the midspan. Test specimens had nominal width and thickness of 1 in. and 0.25 in., respectively. Four different span lengths of 4 in., 6 in., 9 in., and 12 in. were investigated. Analysis of the results showed that the non-linear deflection behavior can be estimated reasonably well by adopting the conventional deflection equation pertaining to an assumed linear elastic material, but after replacing the modulus of elasticity with a secant modulus corresponding to the maximum tension strain resulting from the applied load.

This thesis aimed at the development of a fibre optic strain sensor-based damage detection and evaluation system (FODDAS) based on the composite beams. EFPI strain sensors were used with their integrity being assessed. Their performance, either bonded on the surfaces or embedded was examined extensively. They were shown to be adequate and reliable for strain measurements. Through-the-width damages were simulated by artificially-embedded delaminations, which were located at several through-the-thickness locations, each with two different sizes. The overall design considerations were guided by ply stresses and strains which were estimated by using the modified classical lamination theory (CLT). Considerable efforts were devoted to assessing the through-the-thickness mechanical behaviours of the beams containing optical fibres in three-point bending and short beam shear (SBS). They involved various optical fibre orientations with respect to 00 plies / longitudinal axis and at various through-the-thickness locations, each with different number of optical fibres. The understanding of these behaviours paved the way for the evaluation of the beam-based FODDAS. Smart preconditioned beams were subjected to the quasi -static loads whose magnitudes and locations were required to be well controlled. The viability and effectiveness of the beam-based FODDAS was evaluated in terms of strength and strain obtained by the embedded sensor as well as the surface-bonded strain gauges via the cross comparison of ten cases. For the strength, each beam was incrementally loaded up to the ultimate failure either in three-point bending or SBS. After each increment, the beam was unloaded and inspected for damage. For the given locations of EFPI-SS and artificial delamination as well as the sizes of the latter, it was found that the embedded EFPI-SSs were capable of picking up the stiffness degradation when the 10- mm as well as the 20-mm delamination was located at the 29-30 ply interface in the tensile region of a 32-ply quasi-isotropic carbon/epoxy smart composite beam. It was speculated from single tests results that the propagation of the embedded delamination of the sufficient size was able not only to be detected but also to be monitored by the sensors.

In order to elucidate the effects of NPY directly on bone tissue, two different doses of NPY (NPY dose 1= 1X10-5 M and NPY dose 2 = 1X 10&amp / #65533 / 6 M) and NPY dose 2 plus its inhibitor were applied together with hyaluronic acid (HA) into the intramedullary area of right tibia of Wistar rats. HA alone was administered as the control group. On three time points, day one, week one and week two after administration, the tibiae were collected and stored at &amp / #65533 / 20oC for analysis. Evaluation was performed via conventional radiography, dual energy X-ray absorbtiometry (DEXA), quantitative computerized tomography (QCT), three point bending test (TPB) and histology techniques. QCT was used to assess both atomic content and density of both medulla and cortex of tibiae. From DEXA results, it was observed that inhibition of NPY causes an increase in the bone mass from first day to second week. This phenomena was also observed in histology results so that new bone formation in the inhibitor administered bone was encountered at week two. In both medulla and cortex areas&amp / #65533 / atomic content, an increase in average effective atomic number was displayed after administration of NPY plus NPY inhibitor throughout two weeks. In addition, density of medulla of tibiae measured by QCT also revealed an increase in bone mass when inhibitor is applied throughout two weeks. As a result, overall evaluation of data obtained from DEXA, QCT and histological analysis revealed that NPY inhibits bone formation or have a pro-osteoclastic effect / inversely HA displayed osteogenic effect.

This study investigates the effect of strain rate on fracture properties of Ferritic-Pearlitic Ductile Iron. A series of dynamic three point bending tests, with various load application rates, are conducted on Charpy V-notch specimens, in room temperature and approximately -18 °C. The tests are performed in a custom-made fixture and during the tests, force and displacement data are recorded. A XFEM (Extended Finite Element Method) model of the test setup has been established and material data from the tests are used as input to the model. The test results show a strong dependency of the strain rate regarding the force needed for crack initiation. Moreover, it can be concluded that low temperature makes the material very brittle, even at low load application rates.

Recently, additive manufacturing (AM), or "3D printing," is expanding into civil infrastructure applications, particularly cementitious materials. To ensure the safety, health, and welfare of the public, quality assurance and quality control (QA/QC) methods via standardized testing procedures are of the upmost importance. However, QA/QC methods for these applications have yet to be established. This thesis aims to implement existing ASTM standards to characterize additive manufactured cementitious composites and to gather better information on how to tackle the challenges that are inherent when printing with cementitious materials. In this work, fresh mix properties and hardened concrete properties were investigated using current ASTM standards as a starting point for applying or adapting them for AM applications. Specifically, this project applied existing ASTM standards for fresh mix mortars to measure setting time, flow, and early compressive strength as qualitative indicators of printability, pumpability, and buildability. The fresh mix properties were investigated for 12 different mortar mixes to demonstrate the effect that moisture content, absorption, and sand type can have on these fresh mix properties. The results for setting time and compressive strength demonstrated that there was less variability in the properties when the moisture condition of the aggregate was measured and accounted. Flow was shown to be strongly influenced by the sand type. Additively manufactured mortars were used to print a box in a layer-by-layer process. To evaluate the effect of layering on the flexural strength, three-point bending tests were implemented using four different loading orientations to explore the anisotropic mechanical properties. The observed anisotropic behavior was corroborated with stereo-digital image correlation data showing the stress-strain and load-deflection relationships. Two orientations (A and B) demonstrated brittle behavior while the other two orientations (C and D) experienced quasi-brittle behavior. In addition, setting a minimum unit weight of 132 pcf enabled an analysis of the effect that defects had on the mechanical performance: specimens greater than 132 pcf demonstrated greater and less variable strengths than the specimens less than 132 pcf. The discussion of how defects impacted performance of the different orientations can be valuable when determining how to effectively model, design, and inspect 3D printed structures in the future. The findings of this thesis confirm that existing ASTM standards for mortars can be modified and applied to AM cementitious composites for QA/QC. It is recommended that mixtures used in 3D printing of cementitious composites should design and accommodate the moisture condition of the aggregate to optimize the predictability of the fresh and early-age properties. For the hardened properties, it is recommended that testing procedures such as flexural testing account for anisotropic behavior. Furthermore, for implementation of 3D printed concrete structures, it is highly recommended that design is a function of loading orientation due to the anisotropic properties of the composite. / Master of Science / Recently, additive manufacturing (AM), or "3D printing," is expanding into civil infrastructure applications, specifically cementitious materials such as mortar and concrete. Understanding and predicting the behavior of the materials when using this new technique is vital for quality assurance and quality control (QA/QC). However, standard test methods have yet to be established for this new construction technique. This thesis aims to use existing testing standards to characterize AM cementitious composites and to gather better information on how to tackle the challenges of printing with these materials. In this work, properties before and after the materials hardened were studied by adapting current testing standards. Specifically, this project applied existing testing standards for fresh mix mortars to measure setting time, flow, and early compressive strength. These properties can serve as indicators of specific printing requirements. The fresh mix properties were studied for 12 different mortar mixes to show the effect of moisture content, absorption, and sand type. The results suggest that there was less variability in the properties when the moisture condition and type of the aggregate was accounted. The fresh mix materials were printed in a layer-by-layer process and then hardened in place. The effects of the layers were explored by performing flexure tests using four orientations with respect to how the load was applied to the layers. The observed difference in behavior for the different orientations was supported by digital image correlation data. In addition, an analysis of the effect defects had on the performance was included. Understanding how defects impacted performance can be valuable for effectively designing 3D printed structures in the future. The results of this thesis confirm that existing testing standards for mortars can be adapted and applied to AM cementitious materials for QA/QC. It is recommended that mixtures used in 3D printing of cementitious materials should account for the moisture condition of the aggregate to improve the predictability of the fresh and early-age properties. For the hardened properties, it is recommended that the design is a function of loading orientation due to the difference in behavior for the different orientations of the material.

A literatura atual aponta o exercício físico como uma das estratégias nãofarmacológicas mais utilizadas no tratamento e prevenção de condições que acometem o tecido ósseo. Ademais, estudos indicam que a suplementação de creatina pode exercer efeitos positivos sobre o ganho de massa óssea. Sendo assim, o objetivo deste estudo foi investigar os efeitos preventivos do exercício físico associado à suplementação de creatina na perda de massa óssea em ratas ovariectomizadas. Diante disso, sessenta e cinco ratas da linhagem Wistar foram pareadas pelo peso corporal e dividas aleatoriamente em cinco grupos, sendo eles: 1) ratas falso-operadas (SHAM); 2) ratas ovariectomizadas (OVX), sedentárias e suplementadas com placebo (PL); 3) ratas OVX, sedentárias e suplementadas com creatina (CR); 4) ratas OVX, treinadas e suplementadas com placebo (PL+TR) e 5) ratas OVX, treinadas e suplementadas com creatina (CR+TR). Os animais foram submetidos a um protocolo de treinamento físico em declive em esteira rolante e suplementados com creatina diariamente por meio de gavagem esofágica. Foi realizada a avaliação de densitometria óssea para a obtenção dos parâmetros ósseos de conteúdo mineral ósseo (CMO) e densidade mineral óssea (DMO) de corpo total e regional, assim como a composição corporal nos períodos pré e pósintervenção. Além disso, foi removido o fêmur direito para a análise biomecânica. Após a intervenção, o grupo PL+TR apresentou maiores valores de CMO e DMO em comparação ao grupo PL (p=0,004 e p=0,020, respectivamente), ao passo que o grupo CR+TR experimentou maiores incrementos para o CMO e tendência ao aumento da DMO em comparação ao grupo CR (p=0,011 e p=0,064). A análise biomecânica do fêmur demonstrou que ambos os grupos treinados (PL+TR e CR+TR) apresentaram valores de força máxima significantemente maiores em relação aos grupos SHAM (p=0,024 e p=0,020, respectivamente), PL (p<0,001 e p<0,001) e CR (p=0,002 e p=0,002). Com relação à rigidez do fêmur, observou-se que o grupo SHAM não apresentou diferença significante quando comparado à ambos os grupos treinados (p=0,973 vs. PL+TR e p=0,998 vs. CR+TR), entretanto, apresentou diferença significante em relação aos grupos sedentários (p=0,048 vs. PL e p=0,024 vs. CR), ainda para esse parâmetro, o grupo PL apresentou diferença significante em relação ao grupo PL+TR (p=0,009), assim como o grupo CR foi significantemente diferente em relação ao grupo CR+TR (p=0,043). Não houve diferenças significantes entre os grupos PL e CR e entre os grupos PL+TR e CR+TR ao longo do estudo. Dessa forma, concluímos que a suplementação de creatina não apresentou efeitos isolados, nem aditivos, quando combinada ao treinamento físico, porém, o exercício físico promoveu efeitos positivos sobre o tecido ósseo, enfatizando, portanto, o seu papel terapêutico ímpar em atenuar a perda de massa óssea / The current literature indicates exercise training as one of the most used nonpharmacological strategies in the treatment and prevention of conditions that affect the bone tissue. Moreover, studies indicate that creatine supplementation may exert positive effects on bone mass gain. Thus, the aim of this study was to investigate the preventive effects of exercise training associated with creatine supplementation on bone loss in ovariectomized rats. Thus, sixty-five female Wistar rats were matched by body weight and randomly assigned into five experimental groups, as follows: 1) shammed (SHAM); 2) ovariectomized (OVX), sedentary and placebo-supplemented rats (PL); 3) OVX, sedentary and creatine-supplemented rats (CR); 4) OVX, trained and placebo-supplemented rats (PL+TR) and 5) OVX rats, trained and creatinesupplemented rats (CR+TR). The animals were submitted to a downhill running training protocol performed on a treadmill and supplemented with creatine on daily basis via gavage. Bone density were evaluated pre and post-intervention to obtain bone mineral content (BMC) and bone mineral density (BMD) from whole body and regional area, as well as body composition. Right femur was removed to biomechanical assessment. After the intervention, PL+TR group had higher BMC and BMD compared to the PL group (p=0.004 and p=0.020, respectively), while the CR+TR group experienced greater increases in BMC and tended to increase BMD compared to the CR group (p=0.011 and p=0.064, respectively). Biomechanical assessment demonstrated significantly higher femur maximum strength of both trained groups (PL+TR and CR+TR) compared to SHAM group (p=0.024 and p=0.020, respectively), PL group (p<0.001 and p<0.001) and CR group (p=0.002 and p=0.002). With respect to femur stiffness, no significant difference was observed from the SHAM group compared to both trained groups (p=0.973 vs. PL+TR and p=0.998 vs. CR+TR), however, significant difference was observed when compared to sedentary groups (p=0.048 vs. PL and p=0.024 vs. CR), moreover, significant difference was observed when the PL group was compared to PL+TR group (p=0.009), as well as the CR group was significantly different compared to the CR+TR group (p=0.043). There were no significant differences between PL and CR groups and between PL+TR and CR+TR groups along the study. Thus, we conclude that creatine supplementation showed no isolated, nor additive effects when combined with exercise training, however, exercise training promoted positive effects on bone tissue, thus emphasizing its unique therapeutic role in attenuating the loss of bone mass

Os materiais cerâmicos são utilizados pelo homem há milhares de anos e podem ser considerados os primeiros materiais utilizados na fabricação de ferramentas. Argamassas são materiais cerâmicos formados pela mistura de cimento, areia e água, são fluidos nas primeiras horas e endurecem com o tempo, ganhando resistência mecânica, já os refratários são materiais constituídos basicamente por duas partes, uma de granulometria fina denominada matriz e a outra de granulometria grosseira, chamada agregado, trabalham em altas temperaturas e muitas vezes sofrem choques térmicos. Devido a sua fragilidade, são susceptíveis a fratura catastrófica, por isso o conhecimento de seu comportamento mecânico é tão importante. Uma importante propriedade dos materiais cerâmicos é a energia de fratura e o método mais conhecido para a sua determinação é o da barra entalhada flexionada em três ou quatro pontos, porém o grande problema deste método é a relação de tamanho de agregado/área de fratura, pois como a barra apresenta, em geral, pequenas dimensões, o material pode apresentar um agregado de dimensões próximas à dimensão da área de fraturada e o resultado final pode ser fortemente afetado. Então, em 1986, Tschegg patenteou o método da cunha (wedge splitting test) que minimiza este efeito, devido à utilização de amostras com grande área de fratura. Desde então, este método vem sendo utilizado com freqüência por diversos pesquisadores no mundo. Porém não há estudos publicados que definam a posição ideal dos roletes do dispositivo de teste, levando ao uso de diferentes posições, sem que se saiba como isso pode influenciar o ensaio. Além de não existir uma definição de, a partir de que tamanho de agregado o método da barra entalhada passa a ser desaconselhável sendo necessário o uso do método da cunha. Neste trabalho analisou-se a influência da posição dos roletes e do tamanho de agregados nas medidas de energia de fratura e na carga máxima atingida no ensaio. / The ceramic materials are used by humans for thousands of years and can be considerate the first materials used in the manufacture of tools. Mortar are ceramic materials made by the mixture of cement, sand and water, it is fluid in the first hours and stiffen over time, gaining mechanical strength, the refractories in turn are made basically of two phases, one of fine granulometry called matrix and another of coarse called aggregate. It works over high temperature and many times suffer thermal shock. Due to its fragility, it is susceptible to catastrophic fracture; therefore the knowledge of its mechanical behavior is so important. One of the mainly properties of ceramic materials is the fracture energy and o most knew method for its determination is of three-point bending test on notched beams, but the biggest problem of this method is the relation between aggregate size and fracture area, because as the beam has small dimensions the aggregate can have a dimension so closed of the fracture area dimension and the final result can be tightly affect. Then in 1986, Tschegg patented the wedge splitting test, which minimizes this effect, because of the use of samples with a big fracture area. Since then, this method has been used for scientists around the world. But there are no studies that define the roll position of the test device, leading to the use of different positions, without know how it can influence the test. Besides not having a definition of from what aggregate size the wedge splitting test is advisable in despite of the bending test on notched beams. In this work was analyzed the influence of the rolls positions in the wedge splitting test and of the aggregate size in the measures of fracture energy and maximum load of test.