Due to its relative avascularity, low cellularity and lack of an undifferentiated cell reservoir, articular cartilage has a limited capacity for self-repair when damaged through trauma or disease. Articular cartilage impairment and the resultant reduced joint function affects millions of people at a substantial cost. In the U.S. alone, over 20 million adults are afflicted with osteoarthritis, costing more than $65 billion per year in health care and lost wages. Surgical techniques have been developed to address small, focal lesions, but more critical sized defects remain without a viable solution. Tissue engineering strategies produce cartilage-like constructs in vitro containing living cells in the hope of replacing damaged cartilage and restoring joint function. However, these constructs lack both sufficient integration into the surrounding tissue following implantation and the mechanical properties capable of withstanding the demanding and complex in vivo loading environment. Our central hypothesis is that exposure of engineered cartilage to fluid-induced shear stress increases the collagen content and mechanical properties (tensile and compressive). The overall objective of this project is to modulate the matrix composition and mechanical properties of engineered cartilage to be more like native tissue using a novel bioreactor. Improving the matrix components and mechanical stability of the tissue to be more similar to that of native tissue may aid in integration into a defect in vivo. The central hypothesis was proven in that shear stress potently altered the matrix composition, gene expression and mechanical properties of both thick and thin engineered cartilage. Modulation was found to be highly dependent on shear stress magnitude, duration, and waveform and affected different matrix constituents and mechanical properties in disparate ways. Our overall objective was satisfied on the basis that the bioreactor created stronger engineered tissues, but with the caveat that the tissues showed an increase in presence of type I collagen. Such an effect would be undesirable for articular cartilage engineered tissues, but could be very beneficial in fibrocartilaginous tissues such as that found in the temporomandibular joint. In conclusion, the novel bioreactor system provides a flexible platform technology for the study of three-dimensional engineered tissues, not just articular cartilage.

Södra DuraPulp is a relatively new eco-composite, made from natural wood fibers and polylactic acid (PLA), which comes from corn starch. Until now, there are only few applications for DuraPulp, mainly in the area of design. To find new fields of application, more knowledge about its mechanical material properties are of great interest.This study deals with characterizing the mechanical properties of DuraPulp in an analytical way by means of micromechanical modelling and evaluation with help of Matlab. The mechanical properties for PLA were taken from scientific literature. Not all properties of the wood fibers could be found in literature (particularly Poisson’s ratios were unavailable). Therefore, they partly had to be assumed within reasonable boundaries. These assumptions are later validated regarding their influence on the final product.Figures and tables were used to present and compare the in- and out-of-plane E-Moduli, shear moduli and Poisson’s ratios of DuraPulp. The calculated in-plane E-Moduli were then compared to those obtained from an earlier study, where DuraPulp was tested in tension. The results showed that experimental and analytical values are very similar to each other. / Södra DuraPulp är en relativt ny eco-komposit, tillverkat av naturliga trä fibrer och polylactic syra som kommer från majsstärkelser. I dagsläget finns det få användningsområden för DuraPulp, huvudsakligen används det inom design. För att expandera användningsområdet behövs det mer kunskaper angående de mekaniska egenskaperna för materialet. Studien handlar om att karakterisera de mekaniska egenskaperna för DuraPulp på ett analytiskt sätt i form av mikro-mekanisk modellering och evaluering med hjälp av Matlab. De huvudsakliga mekaniska egenskaperna för PLA kunde hämtas från flera vetenskapliga källor, men de motsvarande mekaniska egenskaperna för fibrer kunde inte alla valideras. Delvis antogs dem i rimliga gränser och deras inverkan validerades med hjälp av en parameter studie.Figurer och tabeller användes för att presentera och jämföra in- och ut-plan E-Moduler, skjuvmoduler och tvärkontraktionstalen av DuraPulp. De beräknade in-plan E-modulerna för DuraPulp jämfördes med motsvarande E-moduler från en tidigare studie där DuraPulp genomgick dragtest. Resultatet visade att analytiska och experimentella värden överensstämmer bra med varandra.

The primary objective of this research program was to investigate the effective modulus of elasticity and shear modulus of brick masonry walls under lateral load, and to to justify using the Jaeger and Mufti method to calculate the effective modulus of elasticity and shear modulus of brick masonry walls. The experimental program involved the testing of three unreinforced brick masonry walls under in-plane and vertical loads. Linear Variable Differential Transducers were used to record the horizontal and vertical displacements of the walls. The experimental results were used to evaluate the modulus of elasticity and the shear modulus of walls under flexure. The experimental results were compared to the finite element analysis results. It was found that the finite element analysis yields similar results to the experimental results. It was also found that the Jaeger and Mufti method to calculate effective modulus of elasticity and shear modulus of brick masonry walls is effective for design purposes.

Resilient modulus is an important property for asphalt concrete design and for mechanistic analysis of pavement response under traffic loading. This study investigates the different factors affecting the resilient modulus of hot mix asphalt. A fractional factorial design of experiment was carried out to investigate six factors each factor was studied at two levels. These factors are: the maximum nominal aggregate size, specimen diameter and thickness, the load pulse form and duration, and the compaction method. Two types of hot mix asphalts with different maximum aggregate sizes (10 mm and 14 mm) were studied. Gyratory and Marshall compaction methods were used to prepare the specimens. Sinusoidal and triangular load pulse forms were used in the measurement of the resilient modulus. This study attempts to examine how the different factors interrelate to affect the resilient modulus. In addition to this, two other investigations will be carried out. The first is the comparison of the strain backcalculated using the resilient modulus test results with the strain measured using strain gages and strain values obtained from finite element modelling (FEM), and determine whether the FEM or the closed form equation is the more accurate method for determining strain. The second is the investigation of the relationship between the flexural, complex and resilient modulus. Analysis of the factorial experimental design showed that the maximum nominal aggregate size is the most important factor affecting the resilient modulus, followed by the load duration, the specimen geometry represented by the thickness and diameter then the interactions between the different factors. The strain comparison suggested that the closed form equations were indeed a suitable approach to determine maximum horizontal strain during a resilient modulus test. The modulus comparison suggested that it is possible to predict either resilient, complex and flexural modulus given that only one of them is known, but only for AC10 specimens.

The primary objective of this research program was to investigate the effective modulus of elasticity and shear modulus of brick masonry walls under lateral load, and to to justify using the Jaeger and Mufti method to calculate the effective modulus of elasticity and shear modulus of brick masonry walls. The experimental program involved the testing of three unreinforced brick masonry walls under in-plane and vertical loads. Linear Variable Differential Transducers were used to record the horizontal and vertical displacements of the walls. The experimental results were used to evaluate the modulus of elasticity and the shear modulus of walls under flexure. The experimental results were compared to the finite element analysis results. It was found that the finite element analysis yields similar results to the experimental results. It was also found that the Jaeger and Mufti method to calculate effective modulus of elasticity and shear modulus of brick masonry walls is effective for design purposes.

This thesis examines how the rheological properties change depending on the composition of hyaluronan, HA and sodium hydroxide, NaOH. This was performed to see if there was any relationship between the rheological properties of a sample depending on different compositions of HA and NaOH. Moreover, the fluidity of the samples was studied by investigating . Five concentrations of HA (11, 18, 20, 25, 33 wt%) were investigated with six concentrations of NaOH (0, 1, 2, 4, 6, 8 wt%). Rheology was used to determine rheological properties of the composition and the rheometric data was obtained from three different measurements: time sweep, frequency sweep and amplitude sweep. G', G'' andwere investigated but no clear correlation was found. However, some patterns were detected for frequency sweep and amplitude sweep. The graphs generally followed the same shape and the compositions with 11% HA generally had the lowest G' and G'' values. Additionally, the majority of the samples, that could be measured, could be defined as fluids, due to  being higher than 1.

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Although it is common to model modulus of elasticity (MOE) and modulus of rupture (MOR) of graded lumber as normal, lognormal, or Weibull distributions, recent theories and empirical practices have cast doubt on these models. Mathematical proofs have been used to shown how the MOR distributions of graded lumber can be derived from the MOR distributions of mill-run populations. The MOR distribution of a graded lumber subpopulation is "pseudo- truncated" and does not exhibit the same theoretical form as the mill-run population from which it was drawn. Therefore, it is essential to explore the properties of mill-run lumber populations and properly characterize their MOE and MOR distributions. To investigate this topic, this dissertation has three objectives: 1) to determine if the within-mill means and standard deviations of MOE and MOR in mill-run southern pine (Pinus spp.) lumber differ over time, 2) to determine the correlations among hand-held grain angle meter readings, MOE, and MOR in mill- run southern pine lumber, and 3) to model statistical distributions of MOE and MOR in mill-run red pine (Pinus resinosa) and spruce (Picea spp.) lumber. This research features four main sections: 1) an introduction summarizing the conclusions of each chapter, 2) a chapter investigating if there are statistically significant differences between the means and variances of MOE and MOR in mill-run southern pine lumber populations at the same mill over time, 3) a chapter evaluating the bivariate correlations among handheld grain angle meter readings, MOR, and three measures of MOE in mill-run southern pine lumber, and 4) a chapter modeling the distributions of MOE and MOR in mill-run red pine and spruce lumber populations and comparing those to previous work on mill-run southern pine lumber populations.

Yes / Articular cartilage is a vascular tissue with limited repair capabilities, leaving an afflicted person in extreme pain. The tissue experiences numerous forces throughout its lifetime. This study focuses on development of a novel hydrogel composed of chitosan and β-glycerophosphate for articular cartilage repair. The aim of this study was to investigate the mechanical properties and swelling behaviour of a novel hydrogel composed of chitosan and β-glycerophosphate for cartilage repair. The mechanical properties were measured for compression forces. Mach-1 mechanical testing system was used to obtain storage and loss modulus for each hydrogel sample to achieve viscoelastic properties of fabricated hydrogels. Two swelling tests were carried out to compare water retaining capabilities of the samples. The hydrogel samples were made of five different concentrations of β-glycerophosphate cross-linked with chitosan. Each sample with different β-glycerophosphate concentration underwent sinusoidal compression forces at three different frequencies -0.1Hz, 0.316Hz and 1Hz. The result of mechanical testing was obtained as storage and loss modulus. Storage modulus represents the elastic component and loss modulus represents the viscosity of the samples. The results obtained for 1Hz were of interest because the knee experiences frequency of 1Hz during walking.