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Controlled Rocking Steel Braced Frames (CRSBFs) have been developed as a high-performance structural solution to resist seismic forces, due to their ability to minimize structural damage and self-centre the structure back to its original position after an earthquake. A CRSBF is intentionally allowed to uplift and rock on its foundation, which acts as the nonlinear mechanism for the system rather than member yielding and buckling. While the CRSBF is in the rocking phase, the response of the system is controlled by prestressing which anchors the frame to the foundation and energy dissipation devices which are engaged by uplift. Although CRSBFs have shown promising structural performance, an assessment of the overall effectiveness of this system must also consider the performance of nonstructural components which have a significant impact on the safety and economic performance of the system. The purpose of this thesis is to compare the performance of nonstructural components in buildings with CRSBFs to their performance in a conventional codified system such as a buckling restrained braced frame (BRBF), while also investigating which design parameters influence nonstructural component demands in CRSBFs. The responses of various types of nonstructural components, including anchored components, stocky unanchored components that slide, and slender unanchored components that rock, are determined using a cascading analysis approach where absolute floor accelerations generated from nonlinear time-history analyses of each structural system are used as input for computing the responses of nonstructural components. The results show that the trade-off of maintaining elastic behaviour of the CRSBF members is, in general, larger demands on nonstructural components compared to the BRBF system. The results also show that the stiffness of the frame and vibration of the frame in its elastic higher modes are the main influencers for nonstructural component demands in buildings with CRSBFs, while energy dissipation has a minimal impact. / Thesis / Master of Applied Science (MASc) / Controlled Rocking Steel Braced Frames (CRSBFs) have been proposed as a high-performance structural system that resists earthquake forces on buildings. This system has the ability to minimize damage to structural members and self-centre the building back to its original position after an earthquake, two characteristics that are typically not achieved by current conventional systems. However, an assessment of the CRSBF’s overall effectiveness cannot be limited to the consideration of only the structural skeleton, as the performance of nonstructural components (e.g. architectural elements, mechanical and electrical equipment, furnishings, and building contents) that are not part of the structural skeleton can have a significant impact on the safety and economic performance of earthquake resisting systems. This thesis compares the demands on nonstructural components in buildings with CRSBFs to their demands in a more conventional system during earthquake motions. The results show that the trade-off for avoiding damage to structural members in the CRSBFs is often higher demands on the nonstructural components.

yes / The behaviour of seismic-resistant buildings relies heavily upon the inclusion of energy dissipating devices. For concentrically-braced frames, this function is accomplished by diagonal bracing members whose performance depends upon both cross-sectional properties and global slenderness. Traditionally preferred rectangular hollow sections are susceptible to local buckling, particularly in cold-formed tubes, owing to the residual stresses from manufacture. This paper explores the response of hollow and concrete-filled circular tubes under cyclic axial loading. The uniformity of the circular cross-section provides superior structural efficiency over rectangular sections and can be further optimised by the inclusion of concrete infill. A series of experiments was conducted on filled and hollow specimens to assess the merit of the composite section. Comparisons were drawn between hot-finished and cold-formed sections to establish the influence of fabrication on member performance. Two specimen lengths were utilised to assess the influence of non-dimensional slenderness. Parameters such as ductility, energy dissipation, tensile strength and compressive resistance are presented and compared with design codes and empirically derived predictions.

Thesis (MScPhysio)--Stellenbosch University, 2012 / ENGLISH ABSTRACT: SYSTEMATIC REVIEW ABSTRACT - BACKGROUND: Ankle Foot Orthoses (AFOs) are considered as the most suitable lower limb orthosis to correct gait deficits related to ankle instability. AFOs are recommended to minimize gait deviations and to correct drop foot or equinus foot in hemiplegic patients. OBJECTIVES - To identify the effectiveness of different ankle orthoses and/or supports on the temporal, spatial, kinetic and kinematic gait parameters. To critically appraise the methodological quality of the included studies and to provide a description of the studies with a view to identify opportunities to improve future research quality. METHODS - Search strategy A comprehensive search was conducted between March and October 2010, and updated in August 2011. Thirteen computerized bibliographic databases were individually searched, namely PubMed Central, Cohrane Library, CINAHL, OT Seeker, SPORTDiscus, PsyARTICLE, PEDro, Proquest, Biomed Central, Science Direct, Clinicaltrials.gov, Web of Science, and Ingenta Connect. All databases were searched since their inception. The following key terms were used: stroke, hemipleg*, assistive device*, ankle foot orthos*, AFO, (splint*), taping, and strapping. A secondary search (pearling) was conducted by screening the reference lists of all eligible full text studies. The authors of the unpublished studies were conducted to minimize publication bias. Selection criteria The following selection criteria applied: all relevant randomized and non-randomized controlled trails published in English; participants were post-stroke patients older than eighteen years; interventions included any type of ankle foot orthosis (AFO), ankle taping or strapping and ankle foot splint without any additional intervention and the comparison/control groups were limited to walking without support, either barefoot or walking with shoes only. Studies were excluded when the outcome measures did not focus on at least one of the following: temporal spatial gait parameters, kinetic gait parameters or kinematic gait parameters. Data collection and analysis Two reviewers independently selected trials for inclusion and assessed methodological quality. The data was extracted by the primary reviewer and validated by a second reviewer. In event of disagreement, a third reviewer was asked to re-evaluate until consensus could be reached. Homogenous data were statistically summarized in sub-group meta-analysis using Revman© Review Manager Software. The results of heterogeneous data were summarized in a narrative form. MAIN RESULTS - The search yielded 11134 initial hits. Sixteen studies met the inclusion/exclusion criteria. The studies investigated the immediate effect of various types of AFOs on a broad range of temporal spatial gait parameters mainly gait speed, cadence, stride and step length. Only two studies reported on the kinetic and six on various kinematic gait parameters. The meta-analysis yielded significant improvement in gait speed (0.06 m/s; 95% CI 0.04, 0.08. p < 00001), walking cadence (5.41; 95% CI 3.79, 7.03. p < 00001), stride length (6.67; 95% CI 3.29, 10.06. p < 00001) and step length (2.66; 95% CI 1.59, 3.72. p < 0.00001). CONCLUSION - AFOs are effective to improve mobility, gait speed, cadence, stride and step length for post-stroke patients and may have a positive impact on the daily function of post-stroke patients. . The long term benefit or adverse effects of AFOs are still inconclusive. The effectiveness of AFOs on the kinetic and the frontal- or transverse- plane joint kinematics is largely unresolved. There is insufficient evidence to either support or refute the effectiveness of taping/strapping and splinting of the ankle on hemiplegic gait. EXPERIMENTAL STUDY ABSTRACT - BACKGROUND: Temporal, spatial and affected ankle kinematic gait parameters of adults with hemiplegia are significantly different from the normal able-bodied population. Enabling hemiplegic patients to walk is a major goal of rehabilitation programs. Taping of the plegic ankle could be utilized by therapists as external support of the ankle to improve foot position and placement during gait rehabilitation. OBJECTIVE - The purpose of the study was to describe the immediate effect of neutral ankle taping on temporal spatial gait parameters and ankle joint kinematics of the affected ankle in ambulant adult hemiplegic patients. METHODS - A clinical trial using a crossover randomized testing order was conducted on a convenient sample of ten ambulant hemiplegic patients at the Physiotherapy and Motion Analysis Clinic, Faculty of Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa. The affected ankle joint was taped in a neutral talocrural dorsiflexion/ plantarflexion and neutral hindfoot inversion/ eversion position using rigid adhesive tape (5 cm). The gait parameters were analysed according to the Plug-In Gait Model using a motion analysis system (Vicon Nexus 1.1.7; Vicon Motion System Limited, Oxford, UK). The analyses were repeated six times for each testing condition and the average values were used for further analysis. The data were analyzed using Least Square Means tests and post hoc Fisher (Least Significant Difference) LSD multiple comparison tests to determine the significant differences at 95% confidence level. RESULTS - The main results of the study indicate that taping of the affected ankle joint in a neutral position does not significantly improve (p>0.5) temporal spatial gait parameters and ankle joint kinematics in ambulant adult hemiplegic patients. The following positive trends were however found and need to be further explored in larger homogeneous study samples: ankle taping of ambulant adult hemiplegic patients has limited benefits on selected temporal parameters as ankle taping could potentially improve cadence. Ankle taping could decrease plantarflexion of the plegic leg at initial contact. CONCLUSIONS - A systematic review revealed no conclusive evidence either to support or refute the beneficial effects of ankle taping on gait parameters of ambulant adult hemiplegic patients. Ankle taping of ambulant adult hemiplegic patients has potential clinical benefits on temporal, spatial and affected ankle kinematics, gait cadence and affected leg swing and stance duration.

The purpose of this study was to determine the influence of dentofacial appearance on perceived social attributes of college-aged adult males and females as judged by their peers. Specifically, the objective was to determine if ideal smile esthetics positively influenced this age group’s perception of opposite-sex peers based on ratings of the following psychosocial characteristics: attractiveness, desire to spend time with, desire to date, and desire for a long-term relationship. Evaluators were shown digital photographs of subjects with ideal and nonideal smiles and asked to rate those 4 attributes using a visual analogue scale (VAS). The subjects’ photographs with ideal smile esthetics were consistently rated higher on average than the same subjects’ photographs with nonideal smile esthetics. The differences in ratings between ideal and nonideal smile images were significant for all 4 psychosocial judgments (P <.0001). These differences ranged in magnitude depending on the sex and race of the evaluator and subject.

El objetivo de este estudio fue evaluar el efecto sobre la fuerza adhesiva (SBS), adhesivo remanente, y superficie del esmalte del recementado de brackets nuevos en la misma superficie de esmalte utilizando distintos métodos de acondicionamiento del esmalte.Utilizamos 135 incisivos bóvinos. Los brackets fueron cementados al esmalte con: (1)acido-fosfórico al 37%, (2)ácido-fosfórico al 37% (antes del primer cementado pero no en los siguientes cementados), (3)Transbond-Plus-Self-Etching-Primer® (TSEP) y (4)acondicionador que no precisa lavado (NRC). Los brackets fueron cementados y descementados tres veces utilizando el mismo procedimiento de acondicionamiento con la excepción del grupo 2 donde no se volvió a grabar con ácido-fosfórico al 37% en la segunda ni tercera secuencias de cementado. SBS y el adhesivo remanente fueron evaluados para cada descementado. Se realizaron observaciones al MEB para cada secuencia de acondicionamiento. Se realizó el análisis estadístico utilizando ANOVA, test de Mann-Whitney, y test de Kruskal-Wallis. / The aims of this study were to evaluate the effect on shear bond strength (SBS), adhesive remnant, and enamel surface of repeated bonding of new brackets on the same tooth using different methods of enamel conditioning.135 bovine incisors were used. Brackets were bonded to enamel using oneof the following conditioning procedures: (1) 37% phosphoric-acid, (2) 37% phosphoric-acid (prior to first bond but not for further bonds), (3) Transbond Plus Self Etching Primer® (TSEP), and (4) non-rinse-conditioner (NRC). Brackets were sequentially bonded and debonded three timesfollowing the same conditioning procedure with the exception of group 2 where 37% phosphoric-acid was not reapplied prior to the second and third bonding sequences. SBS and adhesive remnant were evaluated for each debond. SEM observations were made for each conditioning sequence. Statistical analysis was undertaken using ANOVA, Mann-Whitney, and Kruskal-Wallis tests.

The catastrophic damage to the infrastructure due to the most recent major earthquakes around the world demonstrated the seismic vulnerability of many existing reinforced concrete buildings. Accordingly, this thesis is focused on a proposed seismic retrofitting system (PSRS) configured to upgrade the performance of seismically vulnerable reinforced concrete buildings. The proposed system is composed of a rigid steel frame with chevron braces and a conventional energy dissipating shear link. The retrofitting system is installed within the bays of a reinforced concrete building frame. A retrofitting design procedure using the proposed seismic retrofitting system is also developed as part of this study. The developed design methodology is based on performance-based design procedure. The retrofitting design procedure is configured to provide a uniform dissipation of earthquake input energy along the height of the reinforced concrete building. The PSRS and a conventional retrofitting system using squat infill shear panels are applied to an existing school and an office building. Nonlinear time history analyses of the buildings in the original and retrofitted conditions are conducted to assess the efficiency of the PSRS. The analyses results revealed that the PSRS can efficiently alleviate the detrimental effects of earthquakes on the buildings. The building retrofitted with PSRS has a more stable lateral force-deformation behavior with enhanced energy dissipation capability than that of the one retrofitted with squat infill shear panels. For small intensity ground motions, the maximum inter-story drift of the building retrofitted with the PSRS is comparable to that of the one retrofitted with squat infill shear panels. But for moderate to high intensity ground motions, the maximum inter-story drift of the building retrofitted with the PSRS is considerably smaller than that of the one retrofitted with squat infill shear panels.

Knee osteoarthritis (KOA) is the primary cause of chronic immobility in populations over the age of 65. It is a joint degenerative disease in which the articular cartilage in the knee joint wears down over time, leading to symptoms of pain, instability, joint stiffness, and misalignment of the lower extremities. Without intervention, these symptoms gradually worsen over time, decreasing the overall knee range of motion (ROM) and ability to walk. Current clinical interventions include offloading braces, which mechanically realign the lower extremities to alleviate the pain experienced in the medial compartment of the knee joint. Though these braces have proven effective in pain management, studies have shown a significant decrease in knee ROM while using the brace. Concurrently, development of active exoskeletons for rehabilitative gait has increased within recent years in efforts to provide patients with a more effective intervention for dealing with KOA. Though some developed exoskeletons are promising in their efficacy of fostering gait therapy, these devices are heavy, tethered, difficult to control, unavailable to patients, or costly due to the number of complicated components used to manufacture the device. However, the idea that an active component can improve gait therapy for patients motivates this study. This study proposes the design of an adjustable lower extremity exoskeleton which features a single linear actuator adapted onto a commercially available offloading brace. This design hopes to provide patients with pain alleviation from the brace, while also actively driving the knee through flexion and extension. The design and execution of this exoskeleton was accomplished by 3D computer simulation, 3D CAD modeling, and rapid prototyping techniques. The exoskeleton features 3D printed, ABS plastic struts and supports to achieve successful adaptation of the linear actuator to the brace and an electromechanical system with a rechargeable operating capacity of 7 hours. Design validation was completed by running preliminary gait trials of neutral gait (without brace or exoskeleton), offloading brace, and exoskeleton to observe changes between the different gait scenarios. Results from this testing on a single subject show that there was an observed, significant decrease in average knee ROM in the offloading brace trials from the neutral trials and an observed, significant increase in average knee ROM in the exoskeleton trials when compared to the brace trials as hypothesized. Further evaluation must be completed on the clinical efficacy of this device with a larger, and clinically relevant sample size to assess knee ROM, pain while using the device, and overall comfort level. Further development of this design could focus on material assessment, cost analysis, and risk mitigation through failure mode analysis.