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The inception of the human-powered water pump began during my trip to Maasailand in Kenya over the Summer of 2017. Being one of the few Broadening the Reach of Engineering through Community Engagement (BRECE) Scholars at Arizona State University, I was given the opportunity to join Prescott College (PC) on their annual trip to the Maasai Education, Research, and Conservation (MERC) Institute in rural Kenya. The ASU BRECE scholars that choose to travel were asked to collaborate with the local Maasai community to help develop functional and sustainable engineering solutions to problems identified alongside community members using rudimentary technology and tools that were available in this resource-constrained setting. This initiative evolved into multiple projects from the installation of GravityLights (a local invention that powers LEDs with falling sandbags), the construction/installation of smokeless stoves, and development of a much-needed solution to move water from the rainwater collection tanks around camp to other locations. This last project listed was prototyped once in camp, and this report details subsequent iterations of this human-powered pump.
ContributorsMiller, Miles Edward (Author) / Henderson, Mark (Thesis director) / Abbas, James (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Skin and muscle receptors in the leg and foot provide able-bodied humans with force and position information that is crucial for balance and movement control. In lower-limb amputees however, this vital information is either missing or incomplete. Amputees typically compensate for the loss of sensory information by relying on haptic feedback from the stump-socket interface. Unfortunately, this is not an adequate substitute. Areas of the stump that directly interface with the socket are also prone to painful irritation, which further degrades haptic feedback. The lack of somatosensory feedback from prosthetic legs causes several problems for lower-limb amputees. Previous studies have established that the lack of adequate sensory feedback from prosthetic limbs contributes to poor balance and abnormal gait kinematics. These improper gait kinematics can, in turn, lead to the development of musculoskeletal diseases. Finally, the absence of sensory information has been shown to lead to steeper learning curves and increased rehabilitation times, which hampers amputees from recovering from the trauma. In this study, a novel haptic feedback system for lower-limb amputees was develped, and studies were performed to verify that information presented was sufficiently accurate and precise in comparison to a Bertec 4060-NC force plate. The prototype device consisted of a sensorized insole, a belt-mounted microcontroller, and a linear array of four vibrotactile motors worn on the thigh. The prototype worked by calculating the center of pressure in the anteroposterior plane, and applying a time-discrete vibrotactile stimulus based on the location of the center of pressure.
ContributorsKaplan, Gabriel Benjamin (Author) / Abbas, James (Thesis director) / McDaniel, Troy (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This study was conducted to examine the potential effects of exercise training on partial spinal cord injury on locomotor recovery in juvenile rats. Three groups were tested, where three female Long-Evans rats 10-12 weeks of age were studied for their locomotion. All animals underwent a T8-T9 laminectomy and two of the three in each group received a dorsal, partial spinal cord injury. Locomotion was then analyzed every week, over 8-10 weeks. One of the two injured animals was given open access to a wheel after 2 weeks for voluntary exercise training. The results of this study suggested that injured animals displayed more irregular stepping patterns, larger hindlimb bases of support, greater and more variable interpaw distances, slower hindlimb speed, and increased dependency of swing-phase duty cycle on hindlimb speed. Trained animals displayed quicker recovery of stepping patterns, stepping of the hindpaw in relation to the preceding ipsilateral forepaw, and higher swing-duty cycle dependency on hindlimb speed in comparison to injured animals that did not receive exercise training. Due to a small sample size, there was a large amount of variation between individual animals in most parameters. These results are considered to be potential effects that may be seen in further study with a larger sample size. The research team will continue the research project to examine changes in neural pathways in the spinal cord and the effects of exercise on recovery after injury.
ContributorsSleem, Tamara Hatem (Author) / Abbas, James (Thesis director) / Hamm, Thomas (Committee member) / School of Human Evolution and Social Change (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
There are many challenges in designing neuroprostheses and one of them is to maintain proper axon selectivity in all situations. This project is based on an electrode that is implanted into a fascicle in a peripheral nerve and used to provide tactile sensory feedback of a prosthetic arm. This fascicle can undergo mechanical deformation during every day motion. This work aims to characterize the effect of fascicle deformation on axon selectivity and recruitment when electrically stimulated using hybrid modeling. The main framework consists of combining finite element modeling (FEM) and simulation environment NEURON. A suite of programs was developed to first populate a fascicle with axons followed by deforming the fascicle and rearranging axons accordingly. A model of the fascicle with an implanted electrode is simulated to find the electrical potential profile through FEM. The potential profile is then used to compare which axons are activated in the two conformations of the fascicle using NERUON.
ContributorsDileep, Devika (Author) / Abbas, James (Thesis director) / Sadleir, Rosalind (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Electrical stimulation can be used to activate peripheral nerve fibers to restore sensation to individuals with amputation and the technique is also being investigated as a means of treating a wide range of diseases. Longitudinal intrafascicular electrodes (LIFEs) are one of several types of electrodes that have been used to activate peripheral nerves. LIFEs can be used to activate small groups of fibers within a peripheral nerve fascicle, but the degree of their selectivity is uncertain. To investigate the effects of intrafascicular stimulation on nerve fiber activation, a mathematical, conductance-based model of an axon drawn from the literature was implemented and used to simulate the firing response of sensory nerve fibers in the presence of an applied monopolar electric field. Several axons were simulated to represent axons of different size, conductivity, spatial composition and location with respect to the electrode. Electric field profiles produced by pulses of different pulse widths and pulse amplitudes were created. Each fiber was placed within each resulting electric field and the firing threshold was determined. The effects of changes in pulse width, pulse amplitude, and distance on firing patterns were shown; all of these results were consistent with published experimental findings. The models showed lower firing threshold for smaller fibers than larger fibers and for fibers that were farther from the stimulating electrode than those that were closer. Firing threshold was also lower for stimuli of greater pulse width. Analysis of axon recruitment upon increases in pulse amplitude showed that the effects of fiber distance may be more pronounced than the effects of fiber size. This model can serve as a basis for further development to more accurately represent the effects of LIFEs and eventually may assist in the design of stimulation paradigms and waveforms to improve selectivity of axon activation when using LIFEs.
ContributorsSira, Alarmel (Author) / Abbas, James (Thesis director) / Crook, Sharon (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The objective of this thesis project is to identify -- and better meet -- the assistive seating needs of children, ages 5-14, with cerebral palsy. Student needs were assessed through the collection of survey responses from professionals working closely with students who have CP, and interviews conducted by the author with some participants. After performing a detailed needs assessment, specific design changes were suggested for current adaptive seating systems to improve clinical outcomes and user experience for students with cerebral palsy.
ContributorsFahy, Alison (Author) / Abbas, James (Thesis director) / Blain Christen, Jennifer (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2022-05