Matching Items (9)
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- All Subjects: Biomechanics
- Creators: Harrington Bioengineering Program
Description
The global population over the age of 60 is estimated to rise to 23% by 2050 only increase the prevalence of functional neurological disorders and stroke. Increase in cases of functional neurological disorders and strokes will place a greater burden on the healthcare industry, specifically physical therapy. Physical therapy is vital for a patient’s recovery of motor function which is time demanding and taxing on the physical therapist. Wearable robotics have been proven to improve functional outcomes in gait rehabilitation by providing controlled high dosage and high-intensity training. Accurate control strategies for assistive robotic exoskeletons are vital for repetitive high precisions assistance for cerebral plasticity to occur.
This thesis presents a preliminary determination and design of a control algorithm for an assistive ankle device developed by the ASU RISE Laboratory. The assistive ankle device functions by compressing a spring upon heel strike during gait, remaining compressed during mid-stance and then releasing upon initiation of heel-off. The relationship between surface electromyography and ground reactions forces were used for identification of user-initiated heel-off. The muscle activation of the tibialis anterior combined with the ground reaction forces of the heel pressure sensor generated potential features that will be utilized in the revised control algorithm for the assistive ankle device. Work on this project must proceed in order to test and validate the revised control algorithm to determine its accuracy and precision.
This thesis presents a preliminary determination and design of a control algorithm for an assistive ankle device developed by the ASU RISE Laboratory. The assistive ankle device functions by compressing a spring upon heel strike during gait, remaining compressed during mid-stance and then releasing upon initiation of heel-off. The relationship between surface electromyography and ground reactions forces were used for identification of user-initiated heel-off. The muscle activation of the tibialis anterior combined with the ground reaction forces of the heel pressure sensor generated potential features that will be utilized in the revised control algorithm for the assistive ankle device. Work on this project must proceed in order to test and validate the revised control algorithm to determine its accuracy and precision.
ContributorsGaytan-Jenkins, Daniel Rinaldo (Author) / Zhang, Wenlong (Thesis director) / Tyler, Jamie (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
With dwindling water resources due to drought and other pressures, water utilities are seeking to tap into alternative water sources as a means to improve water sustainability. Reclaimed water consists of treated wastewater and is widely used for non-potable purposes, such as irrigation, both agricultural and recreational. However, the reclaimed water distribution system can be subject to substantial regrowth of microorganisms, including opportunistic pathogens, even following rigorous disinfection. Factors that can influence regrowth include temperature, organic carbon levels, disinfectant type, and the time transported (i.e., water age) in the system. One opportunistic pathogen (OP) that is critical to understanding microbial activity in both reclaimed and drinking water distribution systems is Acanthamoeba. In order to better understand the potential for this amoeba to proliferate in reclaimed water systems and influence other OPs, a simulated reclaimed water distribution system was studied. The objective of this study was to compare the prevalence of Acanthamoeba and one of its endosymbionts, Legionella, across varying assimilable organic carbon (AOC) levels, temperatures, disinfectants, and water ages in a simulated reclaimed water distribution system. The results of the study showed that cooler temperatures, larger water age, and chlorine conditions yielded the lowest detection of Acanthamoeba gene copies per mL or cm2 for bulk water and biofilm samples, respectively.
ContributorsDonaldson, Kandace (Author) / Ankeny, Casey (Thesis director) / Edwards, Marc (Committee member) / Pruden, Amy (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Across primates, molar-emergence age is strongly correlated to life-history variables, such as age-at-first-reproduction and longevity. This relationship allows for the reconstruction of life-history parameters in fossil primates. The mechanism responsible for modulating molar-emergence age is unknown, however. This dissertation uses a biomechanical model that accurately predicts the position of molars in adults to determine whether molar emergence is constrained by chewing biomechanics throughout ontogeny. A key aspect of chewing system configuration in adults is the position of molars: the distal-most molar is constrained to avoid tensile forces at the temporomandibular joint (TMJ). Using three-dimensional data from growth samples of 1258 skulls, representing 21 primate species, this research tested the hypothesis that the location and timing of molar emergence is constrained to avoid high and potentially dangerous tensile forces at the TMJ throughout growth. Results indicate that molars emerge in a predictable position to safeguard the TMJ during chewing. Factors related to the size of the buffer zone, a safety feature that creates greater stability at the TMJ during biting, account for a large portion of both ontogenetic and interspecific variation in the position of emergence. Furthermore, the rate at which space is made available in the jaws and the duration of jaw growth both determine the timing of molar emergence. Overall, this dissertation provides a mechanical and developmental model for explaining temporal and spatial variation in molar emergence and a framework for understanding how variation in the timing of molar emergence has evolved among primates. The findings suggest that life history is related to ages at molar emergence through its influence on the rate and duration of jaw growth. This dissertation provides support for the functionally integrated nature of craniofacial growth and has implications for the study of primate life history evolution and masticatory morphology in the fossil record.
ContributorsGlowacka, Halszka (Author) / Schwartz, Gary T (Thesis advisor) / Kimbel, William H. (Committee member) / Reed, Kaye E (Committee member) / Wright, Barth W (Committee member) / Arizona State University (Publisher)
Created2017
Description
The bony pelvis is a pivotal component of the locomotor system, as it links the hindlimb with the trunk and serves as anchorage for the primary propulsive musculature. Its shape is therefore expected to be adapted to the biomechanical demands of habitual locomotor behavior. However, because the relationship between locomotor mechanics and pelvic morphology is not well understood, the adaptive significance of particular pelvic traits and overall pelvic shape remains unclear. This study used an integrative, dual approach to elucidate the relationship between form and function in the primate pelvis. A biomechanical cylinder model of pelvic stress resistance was tested using in vitro strain analysis of monkey and ape cadaver specimens. These results were used to refine adaptive hypotheses relating pelvic form to locomotor mechanics. Hypotheses of adaptation were then tested via univariate and geometric morphometric methods using a taxonomically broad, comparative sample of 67 primate taxa. These results suggest that the pelvis exhibits some iliac and ischial adaptations to stress resistance that are associated with the biomechanical demands of habitual locomotor loading and of body size. The ilium and ischium exhibit relatively low levels of strain during experimental loading as well as adaptations that increase strength. The pubis exhibits relatively high strains during loading and does not vary as predicted with locomotion. This integrated study clarifies the relationship between strain and adaptation; these results support the hypothesis that bones adapted to stress resistance exhibit low strains during typical loading. In general, the cylinder model of pelvic biomechanics is unsupported. While the predictions of loading regimes were generally rejected, the inability of these methods to test the possible occurrence of overlapping loading regimes precludes outright rejection of the cylinder model. However, the lack of support for predicted global responses to applied loading regimes suggests that pelvic stress resistance may be better explained by a model that accounts for local, functional subunits of pelvic structure. The coalescence of a localized model of pelvic biomechanics and comparative morphometrics has great potential to shed light on the evolution of the complex, multi-functional structure of the pelvis.
ContributorsLewton, Kristi Lynn (Author) / Spencer, Mark A. (Thesis advisor) / Reed, Kaye E (Committee member) / Schwartz, Gary T (Committee member) / Ward, Carol V. (Committee member) / Arizona State University (Publisher)
Created2010
Description
The effect of conflicting sensorimotor memories on optimal force strategies was explored. Subjects operated a virtual object controlled by a physical handle to complete a simple straight-line task. Perturbations applied to the handle induced a period of increased error in subject accuracy. After two blocks of 33 trials, perturbations switched direction, inducing increased error from the previous trials. Subjects returned after a 24-hour period to complete a similar protocol, but beginning with the second context and ending with the first. Interference from the first context on each day caused an increase in initial error for the second (P < 0.05). Following the rest period, subjects showed retention of the sensorimotor memory from the previous day through significantly decreased initial error (P = 3x10-6). However, subjects showed an increase in forces for each new context resulting from a sub-optimal motor strategy. Higher levels of total effort (P < 0.05) and a lack of separation between force values for opposing and non-opposing digits (P > 0.05) indicated a strategy that used more energy to complete the task, even when rates of learning appeared identical or improved. Two possible mechanisms for this lack of energy conservation have been proposed.
ContributorsSmith, Michael David (Author) / Santello, Marco (Thesis director) / Kleim, Jeffrey (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Medial compartment knee osteoarthritis (OA) is a disease whose severity has been associated with the peak adduction moment during walking (pKAM). Unfortunately, measuring patients' pKAM to track their therapy progress involves the use of a gait laboratory which is expensive and time intensive. This study aimed to develop and assess a regression method to predict the pKAM using only plantar pressure measurements. This approach could greatly reduce the burden of evaluating pKAM.
ContributorsThomas, Kevin Andrew (Author) / Hinrichs, Richard (Thesis director) / Harper, Erin (Committee member) / Favre, Julien (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Differences in the postcanine dentition of primates likely represent dietary adaptations given that the teeth interact directly with foods during mastication. Among early hominins, changes to both molar and premolar morphology are purported to indicate consumption of foods differing in their material properties. Some early hominins, such as the robust australopiths, possess premolars that resemble molars with enhancements to the distal part of the tooth (i.e., the talonid), including additional cusps and/or expanded basins. Such molarized premolars are thought to indicate that these hominins were processing mechanically challenging foods; that is, food items that were either hard or tough. Hypotheses tested in this study evaluated the link between the degree of premolar molarization and consumption of mechanically challenging foods in extant primates. Surface anatomy of the distal-most mandibular premolar (the P4) was quantified using a combination of 3D scans of postcanine dental casts and craniodental landmark data collected from 541 individuals, representing 22 extant primate taxa with well-studied diets and known food material properties. Taxa with more mechanically challenging diets were expected to have premolars with expanded talonids and enlarged P4s (and/or molar rows) relative to several mechanically-relevant size proxies. Taxa consuming high proportions of structural carbohydrates were also expected to have postcanine teeth with high occlusal relief (RFI), sharpness (DNE), and complexity (OPCR). Taxa consuming harder food items were expected to have lower relief and higher complexity, with sharpness determined by the proportion of structural carbohydrates included in their diet. The work presented in this dissertation supports most of these expectations, though talonid expansion per se was not clearly linked to the consumption of any particular diet. Overall, taxa with more mechanically challenging diets generally had relatively enlarged premolars when compared to taxa with softer diets and also differed predictably in their occlusal topography. The results of this dissertation support the functional significance of P4 crown size and measures of dental topography as they relate to diet and have implications for improving dietary inferences from the fossil record.
ContributorsDaly, Elizabeth Susanne (Author) / Schwartz, Gary T (Thesis advisor) / Delezene, Lucas K (Committee member) / Kimbel, William H (Committee member) / Arizona State University (Publisher)
Created2021
Description
Human walking is a complex and rhythmical activity that comprises of the brain, nerves and muscles. Neuromuscular disorder (NMD) is a broad term that refers to conditions that affect the proper use of muscles and nervous system, thus also impairing the walking or gait cycle of an individual. The improper gait cycle might be attributed to the lack of force produced at the toe-off stage. This project addresses if it is possible to create an OpenSim model to find the ideal time and force magnitude needed of an assistive force ankle device to improve gait patterns in individuals with NMD.
ContributorsRivera, Jose Luis (Author) / Zhang, Wenlong (Thesis director) / Lockhart, Thurmon (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Over the past 30 years the use of graphene has been increasing at a rapid rate. The reason why graphene has become more popular is because it is starting to be understood better, and researchers are starting to recognize graphene’s unique properties. Graphene is a single atomic layer of graphite, and graphite is a three-dimensional cube base structure of carbon. Graphite has a high conductivity rate, and graphene has an even higher conductivity, meaning that graphene makes for an excellent resistor in any hardware system. Graphene is flexible, has high durability, and can vary in resistance based on its shape (Sharon 2015). With graphene being able to change its resistivity, it can act as different types of sensors. These sensors include measuring pressure, resistance, force, strain, and angle. One problem across the globe is that patients have arthritis, decaying bone density, and injuries which can easily go mistreated or not treated at all. It can be hard to determine the severity of injuries in joints by observation of the patient. There are tools and equipment that will allow a doctor to track the force and degrees of motion of certain joints, but they are mostly limited to hospitals. With graphene acting as a sensor it can be embedded into casts, braces, and even clothing. With a mobile sensor that relays accurate and continuous data to a doctor they can more precisely determine a therapy or recovery time that will better suit the patients’ needs. In this project the graphene was used to measure the angle of a patient’s wrist while they were wearing a wrist brace. From the data collected, the graphene was able to track the user’s movement of their wrist as they moved it in a single direction. The data showed the angle of the wrist ranging from zero degrees to 90 degrees. This proves that graphene can shape the way biosensing is accomplished. Biodynamics is a growing field, and with more injuries everyday it is important to study graphene and how it can be used to diagnose and prevent injuries related to joints. Graphene can be used as a biosensor which can then be implemented into a brace to allow for accurate biodynamic tracking.
ContributorsSweeten, William (Author) / Lockhart, Thurmon (Thesis director) / Helms Tillery, Stephen (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05