Effects Of Hip And Ankle Moments On Running Stability: Simulation Of A Simplified Model,
2014
Purdue University
Effects Of Hip And Ankle Moments On Running Stability: Simulation Of A Simplified Model, Rubin C. Cholera
Open Access Theses
In human running, the ankle, knee, and hip moments are known to play different roles to influence the dynamics of locomotion. A recent study of hip moments and several hip-based legged robots have revealed that hip actuation can significantly improve the stability of locomotion, whether controlled or uncontrolled. Ankle moments are expected to also significantly affect running stability, but in a different way than hip moments. Here we seek to advance the current theory of dynamic running and associated legged robots by determining how simple open-loop ankle moments could affect running stability. We simulate a dynamical model, and compare it …
Principle Of Bio-Inspired Insect Wing Rotational Hinge Design,
2014
Purdue University
Principle Of Bio-Inspired Insect Wing Rotational Hinge Design, Fan Fei
Open Access Theses
A principle for designing and fabricating bio-inspired miniature artificial insect flapping wing using flexure rotational hinge design is presented. A systematic approach of selecting rotational hinge stiffness value is proposed. Based on the understanding of flapping wing aerodynamics, a dynamic simulation is constructed using the established quasi-steady model and the wing design. Simulations were performed to gain insight on how different parameters affect the wing rotational response. Based on system resonance a model to predict the optimal rotational hinge stiffness based on given wing parameter and flapping wing kinematic is proposed. By varying different wing parameters, the proposed method is …
Intranuclear Strain Measured By Iterative Warping In Cells Under Mechanical And Osmotic Stress,
2014
Purdue University
Intranuclear Strain Measured By Iterative Warping In Cells Under Mechanical And Osmotic Stress, Jonathan T Henderson
Open Access Dissertations
The nucleus is a membrane bound organelle and regulation center for gene expression in the cell. Mechanical forces transfer to the nucleus directly and indirectly through specific cellular cytoskeletal structures and pathways. There is increasing evidence that the transferred forces to the nucleus orchestrate gene expression activity. Methods to characterize nuclear mechanics typically study isolated cells or cells embedded in 3D gel matrices. Often report only aspect ratio and volume changes, measures that oversimplify the inherent complexity of internal strain patterns. This presents technical challenges to simultaneously observe small scale nuclear mechanics and gene expression levels inside the nuclei of …
Theory For Diffusional Encounters In Heterogeneous Environments And Multivalent Electrolyte Screening Of Charged Interface,
2014
Purdue University
Theory For Diffusional Encounters In Heterogeneous Environments And Multivalent Electrolyte Screening Of Charged Interface, Ran Li
Open Access Dissertations
We develop a theory for encounter rates in a three-dimensional system of connected compartments. The model of connected compartments exhibits the length-scale dependent diffusion that is observed in many heterogeneous environments, such as porous catalysts and biological environments. We discovered a dimensionless number that is the dominant scaling variable and obtained, for the first time, an analytical expression for the encounter rate. The new theory generalizes the classic Smoluchowski diffusion limit to the case of heterogeneous environments. The new theory is tested using Brownian dynamics simulations.^ We also experimentally investigated the behavior of multivalent electrolyte near a charged solid-liquid interface. …
Understanding Preferred Leg Stiffness And Layered Control Strategies For Locomotion,
2014
Purdue University
Understanding Preferred Leg Stiffness And Layered Control Strategies For Locomotion, Zhuohua H. Shen
Open Access Dissertations
Despite advancement in the field of robotics, current legged robots still cannot achieve the kind of locomotion stability animals and humans have. In order to develop legged robots with greater stability, we need to better understand general locomotion dynamics and control principles. Here we demonstrate that a mathematical modeling approach could greatly enable the discovery and understanding of general locomotion principles. ^ It is found that animal leg stiffness when scaled by its weight and leg length falls in a narrow region between 7 and 27. Rarely in biology does such a universal preference exist. It is not known completely …
Spatiotemporal Changes In Nuclear Strain Measured By Traction Force Microscopy,
2014
Purdue University
Spatiotemporal Changes In Nuclear Strain Measured By Traction Force Microscopy, Ryan D. Watts, Corey Neu, Jonathan Henderson
The Summer Undergraduate Research Fellowship (SURF) Symposium
The knowledge of how cells interact with and sense their surroundings is missing the key components of time dependency and how substrate stiffness affects amount and rate of strain. This new knowledge of cell-substrate interaction can be applied further to research regarding chromatin spatiotemporal dynamics to better understand gene accessibility for transcription. Studying how the cell functions on a deeper level will provide understanding of cellular morphological changes and proliferation. This study uses the methods of optical microscopy and traction force microscopy (TFM) to image substrate deformation as well as analyze its strain profile to find where forces are interacting …
Development Of Biomechanical Analysis Techniques For Fatigue Of Transtibial Prosthetic Socket And Pylon Interactions,
2014
University of Tennessee at Chattanooga
Development Of Biomechanical Analysis Techniques For Fatigue Of Transtibial Prosthetic Socket And Pylon Interactions, Thomas Z. Sudbury
Honors Theses
The lack of formal, engineering based information is prevalent in the prosthetic industry. Currently, very few prosthetic manufacturing companies can definitively tell their patients how long their products will last. Because of this lack of information, many amputee patients will experience failure of their transtibial prosthetic device during daily activities. One such failure occurs from the fatigue of everyday use. Fatigue failures originate from the repeated application of certain loading conditions. These repeated loads usually occur for millions of cycles before a transtibial prosthetic catastrophically fails. The purpose of this study is to develop a testing procedure and apparatus that …
Application Of Limited Mixing In The Hele–Shaw Geometry In Fabrication Of Janus Hydrogels,
2014
University of Nebraska-Lincoln
Application Of Limited Mixing In The Hele–Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …
Subtalar Fusion Fixture Design And Test,
2014
Western Michigan University
Subtalar Fusion Fixture Design And Test, Nathan Ortiz
Honors Theses
Subtalar arthrodesis is performed when cartilage in the talo-calcaneal (the ankle) joint is degraded in a patient and there are multiple approaches to this surgery. Using synthetic bone material, fixtures were cast from aluminum, using the process of evaporation pattern casting, and epoxy. This casting was used to grip the calcaneus bone of the foot in order to load it mechanically, simulating different scenarios that would be encountered during walking. The relative displacement of the ankle joint was measured using a digital image correlation (DIC) program that was modified to work in both two- and three-dimensional space. This program can …
Hand Prosthesis,
2014
University of Southern Maine
Hand Prosthesis, Tru Nguyen, Aaron Delano, Kyle M. Green, Jorge Maderal, Cody Poland
Thinking Matters Symposium Archive
This project deals with engineering students’ prosthetic hand design, submitted to the University of Southern Maine’s engineering department. The primary goal of the prosthetic hand design is to allow an impaired individual to grasp and hold everyday objects ranging from a toothbrush to a jug of milk. The project consists of three teams each designing their respective portion of the prosthetic device. The teams will deal with three specific design areas; computer aided design of the mechanism, electronic integration, and manufacturing implementation. The design team turns notebook doodles into virtual models in SolidWorks. The electronics team will control a battery …
Developing An Embedded System Solution For High-Speed, High-Capacity Data Logging For A Size-Constrained, Low-Power Biomechanical Telemetry System And Investigating Components For Optimal Performance,
2014
Purdue University
Developing An Embedded System Solution For High-Speed, High-Capacity Data Logging For A Size-Constrained, Low-Power Biomechanical Telemetry System And Investigating Components For Optimal Performance, Brandon Blaine Gardner
Open Access Theses
The Purdue Neurotrauma Group (PNG) seeks to develop a biomechanical telemetry system capable of monitoring and storing athletes' head motions with the intention of identifying when a player may be at risk of neurophysiological damage, especially brain damage. A number of commercially-available systems exist with a similar goal; however, each of these systems discards information below an acceleration threshold. Research by PNG indicates that any acceleration may contribute to brain damage and that, because of this, an event-based model is insufficient for a proper understanding of an athlete's neurophysiological health. Continuous-time monitoring of head accelerations is therefore necessary. To facilitate …
Developing A Hardware Platform For A Low-Power, Low-Cost, Size-Constrained Biomechanical Telemetry System,
2014
Purdue University
Developing A Hardware Platform For A Low-Power, Low-Cost, Size-Constrained Biomechanical Telemetry System, Aditya Balasubramanian
Open Access Theses
As sport-related traumatic brain injuries face increasing attention from the media and the general public, the need to be able to detect brain injury quickly, inexpensively and accurately is more important than ever. Commercially-available event-based systems exist that claim to achieve this goal; however, they collect little to no continuous-time data and primarily indicate when a pre-determined acceleration threshold has been exceeded under the unvalidated assumption that a potentially concussive blow has occurred. Recent findings by the Purdue Neurotrauma Group (PNG) have indicated that repeated exposure to both concussive and subconcussive blows can result in cumulative trauma disorder. To track …
Characteristics Of Fibrous Tissue At High Rates Of Tensile Loading,
2014
Purdue University
Characteristics Of Fibrous Tissue At High Rates Of Tensile Loading, Benjamin J. Claus
Open Access Theses
The mechanical behavior of fibrous tissue is generally characterized at very low strain rates. However, many injuries occur at high rates of loading, such as those encountered in sporting events or vehicle accidents. An understanding of injury behavior requires the injury process to be recorded at high strain rates. Even at low rates of loading, the injury/failure within tissues occurs quickly. Furthermore, using conventional imaging systems, the surface of a specimen may be well documented throughout an experiment. However, damage formation does not necessarily begin at the surface of the specimen or even on the surface exposed to a camera. …
Biomechanics And Relaxivity For Functional Imaging Of Articular Cartilage Injury And Degradation,
2014
Purdue University
Biomechanics And Relaxivity For Functional Imaging Of Articular Cartilage Injury And Degradation, Kateri Elizabeth Fites
Open Access Theses
Osteoarthritis (OA) is a major debilitating health concern and economic burden worldwide, affecting 27 million people in the United States alone. OA often follows tissue injury, and is marked by changes in the structure and biomechanical function of cartilage, including breakdown of extracellular matrix molecules, loss of bulk tissue stiffness, and increase in articular surface friction and wear. Unlike bone and many other tissues, cartilage lacks an intrinsic capacity for regeneration. Advanced OA is typically diagnosed by patient symptoms (e.g. joint pain) and confirmed by radiographic evaluation of joint space narrowing. However, the application of functional imaging to assess cartilage …
Analysis And Modeling Of The Roles Of Actin-Myosin Interactions In Bladder Smooth Muscle Biomechanics,
2014
Virginia Commonwealth University
Analysis And Modeling Of The Roles Of Actin-Myosin Interactions In Bladder Smooth Muscle Biomechanics, Seyed Omid Komariza
Theses and Dissertations
Muscle mechanical behavior potentially plays an important role in some of the most common bladder disorders. These include overactive bladder, which can involve involuntary contractions during bladder filling, and impaired contractility or underactive bladder, which may involve weak or incomplete contractions during voiding. Actin-myosin cross-bridges in detrusor smooth muscle (DSM) are responsible for contracting and emptying the bladder. The total tension produced by muscle is the sum of its preload and active tensions. Studies suggest that actin-myosin cross-links are involved in adjustable preload stiffness (APS), which is characterized by a preload tension curve that can be shifted along the length …
Design And Validation Of A Computational Model For Study Of Scapholunate Joint Kinematics,
2014
Virginia Commonwealth University
Design And Validation Of A Computational Model For Study Of Scapholunate Joint Kinematics, Edward J. Tremols
Theses and Dissertations
As computational power has increased, computational modeling has become a very promising tool to model the biomechanics of complex joint systems. Musculoskeletal computational models have become more complex when compared to original iterations which utilized a number of simplifications. This thesis utilized a three-dimensional computational model of the wrist joint structure to investigate scapholunate kinematics. The model accurately represented the bony anatomy of the wrist and hand and represented soft tissue structures such as ligaments, tendons, and other surrounding tissues. Creation of the model was done using commercially available computer-aided design and medical image processing software, and utilized the rigid …
Relationships Of Long-Term Bisphosphonate Treatment With Measures Of Bone Microarchitecture And Mechanical Competence,
2014
University of Kentucky
Relationships Of Long-Term Bisphosphonate Treatment With Measures Of Bone Microarchitecture And Mechanical Competence, Jonathan Joseph Ward
Theses and Dissertations--Biomedical Engineering
Oral bisphosphonate drug therapy is a common and effective treatment for osteoporosis. Little is known about the long-term effects of bisphosphonates on bone quality. This study examined the structural and mechanical properties of trabecular bone following 0-16 years of bisphosphonate treatment. Fifty-three iliac crest bone samples of Caucasian women diagnosed with low turnover osteoporosis were identified from the Kentucky Bone Registry. Forty-five were treated with oral bisphosphonates for 1 to 16 years while eight were treatment naive. A section of trabecular bone was chosen from a micro-computed tomography (Scanco µCT 40) scan of each sample for a uniaxial linearly elastic …
Biomechanical Analysis Of Concealed Pack Load Influences On Terrorist Gait Signatures Derived From Gröbner Basis Theory,
2014
Portland State University
Biomechanical Analysis Of Concealed Pack Load Influences On Terrorist Gait Signatures Derived From Gröbner Basis Theory, Sean S. Kohles, Anum Barki, Kimberly D. Kendricks, Ronald F. Tuttle
Biology Faculty Publications and Presentations
This project examines kinematic gait parameters as forensic predictors of the influence associated with individuals carrying concealed weighted packs up to 20% of their body weight. An initial inverse dynamics approach combined with computational algebra provided lower limb joint angles during the stance phase of gait as measured from 12 human subjects during normal walking. The following paper describes the additional biomechanical analysis of the joint angle data to produce kinetic and kinematic parameters further characterizing human motion. Results include the rotational velocities and accelerations of the hip, knee, and ankle as well as inertial moments and kinetic energies produced …
Novel Computational Approaches Characterizing Knee Physiotherapy,
2014
Universidade de Lisboa
Novel Computational Approaches Characterizing Knee Physiotherapy, Wangdo Kim, Antonio P. Veloso, Duarte Araújo, Sean S. Kohles
Biology Faculty Publications and Presentations
A knee joint’s longevity depends on the proper integration of structural components in an axial alignment. If just one of the components is abnormally off-axis, the biomechanical system fails, resulting in arthritis. The complexity of various failures in the knee joint has led orthopedic surgeons to select total knee replacement as a primary treatment. In many cases, this means sacrificing much of an otherwise normal joint. Here, we review novel computational approaches to describe knee physiotherapy by introducing a new dimension of foot loading to the knee axis alignment producing an improved functional status of the patient. New physiotherapeutic applications …
Mechanical Properties Of Bone Due To Sost Expression: Nanoindentation Assessment Of Murine Femurs,
2013
California Polytechnic State University, San Luis Obispo
Mechanical Properties Of Bone Due To Sost Expression: Nanoindentation Assessment Of Murine Femurs, Amir Rafie
Master's Theses
In the human genome, the SOST gene codes for a protein sclerostin. Sclerostin is an osteocyte-expressed negative regulator of bone formation. When the SOST gene is not coded, bone formation is reduced in individuals during skeletal maturation. This study utilizes nanoindentation methods to test for the mechanical properties of bones that both express and do not express the SOST gene. 100 transgenic murine femurs were obtained from Lawrence Livermore Labs in the form of 6 and 8 month SOST transgenic mice, 6 and 12 month SOST knockout mice, and wild type control littermates for each of the 4 age groups. …
