There is conflict between recognized Strength and Conditioning professionals and organizations regarding the most effective methods of teaching the power clean weight training exercise. The area of greatest conflict is related to the effectiveness of whether to specifically introduce and segmentally practice the Double Knee Bend technique or not. Sixty collegiate football players with novice power clean experience were randomly assigned to one of three groups: (1) a group in which the double knee bend technique was taught and practiced segmentally (DKB); (2) a group which was instructed in the same way as the DKB group except that the double knee bend was not specifically taught or practiced segmentally(NDKB), and (3) a control group (CG) which was exposed to an orientation session similar to the first two groups, but was not specifically instructed in the power clean technique. Subjects in all three groups were video taped performing the power clean with a standardized weight both prior to and following a seven week training session. Each video taped trial was randomly assigned to an expert reviewer for qualitative analysis in a blind review. Reviewers rated the three upward movement phases as well as the total upward movement phase of the lift using a published check list and rated the performance from one to five with five being the best technique. The result of the ANOVA and a Scheefe test showed that the two treatment groups both demonstrated significant improvement pre to post test in the power clean technique p<0.01. The control group did not significantly improve over the course of the same training period. In comparing the two treatment groups, the between groups analysis (DKB) and (NDKB) were not significantly different. These results suggest that the double knee technique does not need to be specifically taught or segmentally practiced in order to improve power clean technique among college football players with novice power clean experience. / Ed. D.

The primary purpose of this dissertation was to investigate the effect of training status on adaptations to resistance training. A secondary purpose of this dissertation was to investigate the relationship between subjective and objective forms of monitoring resistance training (RT). The benefits of RT are well understood but training status may be a major influence on training outcomes. Fifteen males of various training status were recruited for this study. Subjects completed 11 weeks of block periodization (BP) training. Subjects were tested for absolute strength (ABS) and relative strength (REL) in the barbell back squat, 0kg and 20kg static jumps (SJ) and 0kg and 20kg countermovement jumps (CMJ). Initial levels of ABS and REL were significantly correlated with rates of improvement for ABS, REL, and SJ and CMJ values. All subjects statistically improved ABS (p

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<p> This thesis deals with the analytical and experimental study of buckling strength, of thin walled channel struts, of different geometrical dimensions. The influence of the dimensions of the columns on the buckling strength has been studied.</p> <p> The experimental work consisted of testing different channels of thin sheeting to failure. Comparison has been made with the previous work done and a comparison is made between the theoretical predicted values and the experimental results. The Appendix includes detailed mathematical procedure and matrices formulations.</p> / Thesis / Master of Engineering (MEngr)

Resistance training (RT)-induced skeletal muscle hypertrophy is partly responsible for the RT-induced increase in strength. Previously, we reported that exercise repetition load played a minimal role in the promotion of RT-induced gains in hypertrophy and strength gains in RT-naïve participants performing RE to volitional failure. Thus, the main aim of this study were to determine the effects of 12 weeks of RT on muscle strength and hypertrophy in a trained population. 49 resistance-trained men (mean ± SEM, 23 ± 1 years, 85.9 ± 2.2 kg, 181 ± 1 cm) were randomly allocated into a lower load-high-repetition group (HR, n=24) or a higher load-low-repetition group (LR, n=25). Repetition load was set so that volitional lifting failure was achieved within the repetition ranges of 20-25 (~35-50% of 1RM) for HR or 8-12 for LR (~70-85% of 1RM). Strength as one repetition maximum (1RM) was assessed pre and post. Changes in lean body mass (LBM), appendicular lean mass (ALM) and leg lean mass (LLM) were assessed using dual-energy x-ray absorptiometry (DXA). There were significant increases in strength in all exercises with no differences between groups (p > 0.05) with the exception of bench press where LR showed a greater increase in 1RM than HR (p = 0.012). Similarly, LBM, ALM, and LLM increased significantly following training in the HR group (1.0 ± 0.9kg, p < .001; 0.8 ± 1.1 kg, p < 0.05; 0.7 ± 0.9 kg, p < 0.01 respectively) and the LR group (1.6 ± 1.4 kg, p < .001; 1.0 ± 1.2 kg, p < 0.05; 0.7 ± 1.0 kg, p < 0.01 respectively) with no significant differences between groups (all p > 0.05). These data show that RE performed to volitional failure using either HR or LR induces similar adaptations strength and lean mass accrual in young resistance-trained men. / Thesis / Master of Science in Kinesiology / Resistance training (RT) results in an increase in muscle growth and an increase in strength. Previously, we have shown in young untrained males, that when exercise is performed until failure, or until the weight can no longer be lifted, that gains in muscle and strength were similar with the use of either light or heavy weights. The purpose of the study was to determine the effects of 12 weeks of RT on muscle growth and strength in young men who were already regularly participating in resistance exercise when performing either lower load high repetition RT (HR) or higher load low repetition RT (LR). Maximum strength and changes in muscle mass were assessed prior to and upon completion of the training protocol. Following 12 weeks of RT both groups increased muscle mass and strength to a similar extent with the exception of bench press which increased more in the LR group.

Indiana University-Purdue University Indianapolis (IUPUI) / Direct bonding of orthodontic brackets often results in decalcification of tooth structure surrounding bracket sites. Glass ionomer cements, while typically leaching fluoride over time, often exhibit a significantly lower bond strength. Fluoride-containing resins generally release high concentrations of fluoride for a short time, then cease to release any significant amount. The purpose of this study was to evaluate the tensile bond strength, fluoride release, hardness, solubility, and sorption of a newly formulated fluoride containing resin. The experimental resins were prepared with 5% and 7.5% fluoride (F-) monomer, and were compared to a fluoride-free control adhesive (Rely-a-Bond Phase II™, Reliance Orthodontics Inc ., Itasca, Ill .). To evaluate tensile bond strength, orthodontic brackets were bonded to bovine teeth and debonded using an lnstron machine. Fluoride release was tested using resin disks stored in deionized water. The fluoride content of the water was determined with an ion-specific electrode. Hardness, solubility, and sorption were tested using disks made of each material. Comparison of experimental and control resins by ANOVA followed by General Linear Models multiple comparisons revealed the control to show a statistically significant difference (p<.0001) for tensile bond strength. Experimental Control 5%F- 7.5%F- Peak Stress (MPa) 4.48±0.65 3.83±0.76 5.31±0.97. Fluoride continued to be released from the experimental resins (5% and 7.5% F-) at 18 days. The control was significantly harder than either of the experimental resins at 1 hour, 24 hours, 1 week, and 1 month (p<.0001). The 5% F- resin exhibited slight solubility (0.10 percent), while the 7.5%F- resin and the control exhibited very little solubility (0.01 percent). Phase II™ exhibited significantly lower sorption at 21 days (0.60 percent, p<.001) than either the 5%F- resin (1.69 percent) or the 7.5%F- resin (1.63 percent). These results indicate that while the experimental resin had lower bond strength, lower hardness, and higher sorption than the control, measurable fluoride was released from the experimental resins for up to 18 days. Further testing is indicated to determine the clinical acceptability of this adhesive.

Indiana University-Purdue University Indianapolis (IUPUI) / Many factors may affect orthodontic bond strength study results. An important variant to consider is the bonding surface contour. Contour alters the proximity of adherent surfaces, the surface area available for adhesion, and the stress distribution. It was the purpose of this study to determine if bracket base or enamel contour affect in vitro bond strengths. Orthos Mini-Diamond (ORMCO Corp.) .0 018" slot central incisor brackets with flattened or unaltered curved bases were bonded (System 1 + self cure resin cement by ORMCO, Corp.) to unaltered and flattened bovine central incisors. Bond strengths were determined by debonding on a Bionix 858 (MTS System Corp.) testing machine. The results showed that unaltered bracket bases bonded on unaltered enamel surfaces (the closest approximation to a clinical situation) had the significantly (p< 0.0002) lowest tensile bond strength among the three combinations. The adhesive remnant index evaluation demonstrated that unaltered bracket base/ unaltered enamel surface (Group II) had significantly higher ARI (less adhesive remaining on enamel) than any of the other groups. A negative correlation between ARI scores and mean bond strength was found. There was not a significant difference between flattened bracket base / flattened enamel surface (Group I) and unaltered bracket base/ flattened enamel surface. The results suggest that the surface convexity and texture of enamel are important variables that can affect bond strength tests results. Standardization of testing protocols and control of the different variables that can affect bond strength are important factors in the testing of orthodontic brackets.

Naturally occurring cellular materials are always optimized in terms of morphology, structural resistance, and functionality. The use of cellular materials is based on the application as well as the loading condition. Cellular materials are composed of an interconnected network of struts, plates, or repeating unit cells, forming edges or faces. The properties of these structures can be tailored according to the requirements by changing one or more of the parameters mentioned above. This makes cellular materials suitable for various applications ranging from aerospace to biomedical. In biomedical applications, these cellular materials can be used to manufacture porous implants to match the properties of the surrounding bone. They can also be used as coatings on solid implants to promote bone tissue ingrowth for better implant fixation. The production of these complex, porous implants using traditional manufacturing methods is a difficult task. However, the development of additive manufacturing processes such as Laser Powder Bed Fusion (LPBF) has made it possible to manufacture complex and intricate shaped cellular materials with minimum material wastage and considerable accuracy. Therefore, with the combination of the LPBF process and cellular materials design, it is possible to produce a wide range of cell topologies with customized mechanical properties depending on the implant location, material, and the needs of the patient. Titanium and its alloys such as Ti6Al4V have been used in biomedical applications due to their high strength to weight ratio, corrosion resistance, and good biocompatibility. Also, the LPBF process has been used to produce various Ti6Al4V components for various applications including cellular materials. The development of cellular materials for implants is dependent on the relative density, response of the unit cell to loading conditions, and the optimal pore size for bone ingrowth. Studies have been carried out to understand the behavior of the cellular materials under compressive loads since most of the implants experience compression loads during their operation. Nevertheless, the implants also undergo fatigue loading due to day-to-day activities and tensile loads when the implant is loose or when the host performs an extensive physical activity. Therefore, designing and studying the cellular materials for these loads is necessary to completely understand their behavior. Considering the pore size, studies have suggested that a pore size of ~ 800 μm is suitable to induce bone ingrowth after implantation. The cellular materials can be broadly classified into stretching and bending dominated. Stretching dominated cellular materials are characterized by high strength and stiffness while bending dominated structures are high compliant. This behavior of cellular materials is dependent solely on the unit cell topology. Therefore, the development of different types of cell topologies and their characterization is required to produce optimized fully porous implants. Also, the effect of the LPBF process on the designed parameters of the unit cell alters the obtained mechanical properties from the desired values. The present work aims at developing different Ti6Al4V cellular materials that can be potentially used for application in implants. A combination of different cellular materials can be used to develop completely porous implants or single cellular materials can be used as coatings for solid implants to induce osseointegration. A major portion of the work is focused on the mechanical properties of LPBF manufactured cellular materials characterized using static and fatigue tests. The study also investigates the discrepancy between the as-designed and as-built geometrical parameters of these cellular structures. Finite elements analysis and the Gibson-Ashby modeling has been employed to understand the difference between the as-designed and as-built properties. Another part of the study was focused on the effect of designed geometrical parameters on the as-built geometry of cellular materials. The aim was to develop a relationship between the as-designed and the as-built parameters. This thesis covers all the aspects mentioned in the above paragraph in detail. The research work has been provided in three different chapters (Chapter 2, 3, and 4) which are well connected to each other. Each chapter is composed of an abstract, introduction, materials and methodology, results and discussion, and conclusion. A conclusion on the complete research and the future scope is provided at the end. The first chapter introduces all the aspects concerned with the development of cellular materials for biomedical applications. Literature review on all aspects have been provided, ranging from the properties of the bone, cellular materials, manufacturing process for cellular materials, and the properties of bulk materials suitable for biomedical applications. In chapter 2, Ti6Al4V cellular materials with three different cell topologies namely cubic regular, cubic irregular, and trabecular have been investigated. The irregular specimens are obtained by skewing the junctions of the cubic regular configuration. Trabecular specimens are designed by randomly joining 4-6 struts at a node to mimic human trabecular bone. The three cell topologies were manufactured at three different porosity levels by changing their strut thickness and pore size. The cubic regular cells are considered due to their stable and simple configuration, while irregular and trabecular based specimens have shown promising results in the osseointegration according to the partner company. However, the mechanical properties of irregular and trabecular specimens play an important role in implant design. Therefore, all the specimens were subjected to compression test and as well as a novel tensile test under two different types of loading conditions, monotonic and cyclic to obtain their strength and stiffness. However, a misalignment in the struts with the loading direction in compression led to an asymmetric behavior between tensile and compression. Higher strength and stiffness values were observed under tensile loading, the results of which were in conjunction with the theoretical prediction from the Gibson-Ashby model. The experimental results indicated the irregularity tends to reduce the strength, stiffness and induce bending dominate behavior. Morphological analysis was carried out to obtain the discrepancy between the as-designed and the as-built thickness values. This led to the FE analysis of as-designed models to obtain the difference in the properties of as-designed and as-built cellular materials. Furthermore, as-built FE models were generated using morphological data to study the effect of strut defects and compare them with the experimental results. The next step involved comparing the experimental results with the FE analysis carried out tomography-based FE models. The last part of the study involved obtaining a relation between the as-designed and as-built Young’s modulus for cubic regular, cubic irregular, and trabecular specimens to create a reference database. The mechanical properties from the compression and tensile test of the highest porosity specimens were closer to the properties of human bone. The tensile tests were successful in predicting the mechanical properties accurately. These observations were the motivation to further study the effect of irregularity on various cell topologies, by subjecting them to static and fatigue loads. In chapter 3, seven different types of unit cells, three regular configurations, three irregular configurations, and one trabecular based unit cell. The unit cells used in the study consisted of regular and irregular configurations of the cubic-based, star-based, and cross-based specimens. These specimens were selected to have a comparison of properties from stretching dominate cubic specimen to bending dominated cross-shaped specimens and to study the effect of irregularity. Therefore, the specimens were subjected to and mechanical characterization using compression, tension, and compression – compression fatigue tests along with porosity and morphological analysis. The tensile specimens in this chapter were designed with a thicker transition at the ends, while compression specimens had uniform configuration throughout the specimen. FE analysis was carried on the as-designed configuration of these specimens to study the effect of transition and to compare the as-designed and tensile experimental results to understand the effect of decreased porosity on the failure mechanisms. Fatigue tests were carried under compression-compression load and failure mechanisms in different unit cells were captured. The results of the study indicated that the irregularity has a greater effect on the strength and stiffness of stretching-dominated cellular material and has a negligible effect on bending-dominated cross-based specimens. The trabecular specimens display excellent mechanical properties under static load with good strength, stiffness and sustain high strain values. The normalized S-N curves indicate a clear demarcation between the bending and stretching-dominated cellular materials. The FE analysis showed a similar failure location as compared to the experimental results despite the decrease in the porosity due to manufacturing. The morphological analysis showed the effect of strut orientation of the as-built thickness. The morphological analysis and the difference between the as-designed and as-built geometrical parameters show that an in-depth study on the geometrical deviation due to the LPBF process is necessary. The next chapter focuses on the geometrical deviation in LPBF manufactured cellular specimens and the parameters influencing this deviation. In chapter 4, cubic regular cellular materials with filleted junctions are studied for geometrical deviation and to obtain a relationship between the as-designed and as-built geometric parameters. Initially, nine different specimens with different strut thickness, fillet radius, and unit cell size were manufactured at three different orientations with respect to the printing plane. The main aim of this study was to devise a compensation strategy to reduce the geometrical deviation due to the LPBF process. A linear relation between the as-designed and as-built geometrical values is obtained, which is used for compensation modeling. Struts perpendicular to the building plane were uniform in cross-sections while horizontal and inclined struts had an elliptical cross-section. The internal porosity analysis has been carried out which indicates that the porosity at the junctions is lesser than the porosity at the junctions. The compensation strategy worked well for the second set of specimens produced using the same parameters, thereby reducing the geometrical deviation between the as-designed and the as-built parameters. Finally, the effect of filleted junctions, building directions, and compensation modeling on fatigue properties have been studied. Specimens with load-bearing struts printed parallel to the building plane had the lowest mechanical properties, while the specimens with struts inclined to the loading direction and building plane displayed excellent static and fatigue properties. The fillets at the junctions improve the fatigue resistance of the specimen by reducing the stress concentration. The printing direction and the presence of fillets influence the fatigue failure locations as well. Therefore, filleted junctions that can be reproduced well by the LPBF process can be used to reduce the stress concentration in cellular materials.

This thesis presents a study on the strength properties of the different pervious pavement systems installed at the Stormwater Management Academy field laboratory at University of Central Florida (UCF), Orlando. The strength tests were performed both in the laboratory and in the field. Laboratory testing was conducted to determine the compressive strength and flexural strength of the various pavement surfaces. Evaluation of field pavement performance was performed by comparing the deflection basins using the Falling Weight Deflectometer test on pervious concrete and porous asphalt with conventional impervious concrete and asphalt pavements of similar layer profile and thickness, respectively. From literature and previous work at the academy, it is evident that pervious pavements should not be used to withstand heavy traffic loading. They are mostly used in low traffic volume areas such as parking lots, driveways, walkways and some sub-divisional roads. This research studied the compressive strength and flexural moduli. Also it investigated the relationship between the compressive strength and void ratio, unit weight and volume by carrying out laboratory testing of different pervious pavements such as pervious concrete, porous asphalt, recycled rubber tires, recycled glass and porous aggregate. Different sizes of cylinders and beams were cast in place molds for these laboratory tests. Furthermore, the in-situ resilient moduli of the twenty four pavement sections in our research driveway were back calculated with Modulus 6.0 (Liu, et al., 2001) computer program. The calculated deflection basins were compared to the results obtained from a well known computer program called KENPAVE (Huang, 2004). The design of the requisite pavement layer thickness design was performed by doing hand calculations using American Association of State Highway Transportation Officials (AASHTO) method for flexible and rigid pavements and utilizing a Texas Transportation Institute (TTI) computer software known as FPS 19W (Liu, et al., 2006). The structural number for flexible pavements were calculated and tabulated for two different reliability levels (90% and 95%). Traffic loading was estimated in the absence of actual traffic count measurement devices at the field test site. Based on the laboratory testing, the maximum compressive strength of the cored pervious concrete was about 1730 psi. Backcalculated pervious concrete and porous asphalt moduli values were within the specified range discussed in literature. The in-situ modulus of elasticity range for pervious concrete is found to be 740 - 1350 ksi, for porous asphalt 300 - 1100 ksi, for permeable pavers 45 - 320 ksi, for recycled rubber tire 20 - 230 ksi, recycled glass pavement 850 ksi and porous aggregate 150 ksi. For low volume traffic loading, the minimum layer thickness was calculated for rigid pavements and it is presented in this study. In conclusion, this research summarizes the result of laboratory and field testing performed at the University of Central Florida Stormwater Management Academy Research laboratory to determine the strength related properties of pervious pavement systems.

Stormwater runoff is a major environmental concern, particularly in urban environments. Trends in managing stormwater have evolved (and continue to evolve) from a quantity only approach into a sustainable approach, which integrates quantity, quality, the environment, and aesthetics. Best management practices (BMPs) and Low Impact Development (LID) are two well-documented techniques capable of managing to sustainable standards. There are a number of stormwater models available to design professionals today. However, there are few which integrate site-scale BMP/LID analysis in a simplified fashion. The purpose of this study is to determine if there is a demand in the design profession for simplified stormwater modeling tools to help designers make informed decisions about integrating BMP/LID strategies into site plans. A Web-based questionnaire was administered to a group of design professionals to determine their knowledge of BMPs and their technological needs and preferences in meeting stormwater goals and requirements.