Master of Science, The Ohio State University, 2007, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 2008, Graduate School

Committee: Not Provided (Other) Subjects:

PhD, University of Cincinnati, 2023, Engineering and Applied Science: Mechanical Engineering

A human's interaction with the outside world begins with the human skin and therefore, contact mechanics of human skin is an important area of research. The applications are all-encompassing, from medical technology in the form of drug delivery mechanisms and prosthetics to the digital world in the form of touchscreens or even personal care. The variations in morphological and physiological features in combination with the properties of counter surfaces make human skin contact a complex problem. There are several aspects of this complex tribological system that need to be addressed. These include characterizing the surface topography of human skin, enhancing the predictability of contact parameters, and understanding the mechanics at the interface of such interactions. In this study, as the first specific aim, a method is developed to characterize the directionality of skin tension lines using statistical methods of characterizing rough surfaces. The method is able to capture the increasing anisotropy of human skin with aging. The method can be applied to the surface coordinates of the skin and the pixel intensity data from skin images. The second specific aim is to predict the coefficient of friction considering the changes in the skin's morphological and physiological features. To achieve this, a fractal-based finite element model in combination with an interfacial condition-enhanced empirical method is used. Results show that the proposed approach can replicate several experimental findings from the literature. Human skin in general is a soft material. Therefore, the recent understanding of contact mechanics of soft materials is applicable to skin. The third specific aim is to understand the contact mechanics at the interface of skin interactions. To this end, we use finite element models to first extend the current single asperity studies to three-dimensional soft materials. Specifically, we investigate the role of surface roughness and mate (open full item for complete abstract)

Committee: Kumar Vemaganti Ph.D. (Committee Chair); Bhargava Sista Ph.D. (Committee Member); Manish Kumar Ph.D. (Committee Member); Woo Kyun Kim Ph.D. (Committee Member) Subjects: Mechanical Engineering

Bachelor of Science (BS), Ohio University, 2019, Translational Health

Currently, there is no way to measure bone strength in living people. In the absence of such a measure, areal bone mineral density (aBMD) by dual energy x-ray absorptiometry (DXA) has become the standard used to assess bone health. DXA does not measure bone mechanics and aBMD does not predict fracture risk well. Cortical Bone Mechanics Technology (CBMT) is a device capable of measuring ulna bending stiffness in living people and has been shown to predict bone strength. Previously, Wynnyckyj and colleagues found 14 days of 1 M potassium hydroxide (KOH) treatment on the endocortical surface of emu tibias reduced elastic modulus values by 17% through bone collagen degradation. DXA measurements of aBMD did not change after KOH treatment. The purpose of this study was to determine the accuracy of CBMT in measuring excised human ulna flexural rigidity (EI) and estimating cortical bending strength with potassium hydroxide (KOH) induced collagen degradation by comparing measurements made by quasi-static mechanical testing (QMT). DXA measurements of the ulna were made to test DXA's ability to detect changes in the bone. An additional goal of this study was to compare periosteal (immersion) KOH treatment to the endosteal (endocortical) treatment used in the study performed by Wynnyckyj and colleagues. A randomized experimental design was used in which eight pairs of ulna bones excised from cadaveric human arms were immersed in 1 M potassium hydroxide (KOH) solution or a 0.9% calcium-buffered saline solution. For each pair of arms, the saline solution served as the control for the KOH solution. DXA measurement of ulna area (cm2), BMC (g) and aBMD (g/cm2) at the 1/3 region of the ulna and CBMT and QMT measurement of ulna EI (Nm2) were made before and after immersion. QMT measurements of bone bending strength are destructive and could only be made after immersion. The maximum moment (Mmax, Nm) was used to indicate bone strength. Effect of KOH on bone strength was detected by (open full item for complete abstract)

Committee: Anne B. Loucks PhD (Advisor) Subjects: Biomechanics; Health Sciences; Technology

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Physics

Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee: Not Provided (Other) Subjects: Physics

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1978, Graduate School

Committee: Not Provided (Other) Subjects: Psychology

Doctor of Philosophy, The Ohio State University, 1973, Graduate School

Committee: Not Provided (Other) Subjects: Education

Doctor of Philosophy, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects: Education

Doctor of Philosophy, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects: Education

Master of Science (M.S.), University of Dayton, 2015, Bioengineering

Bioreactor systems used for tissue engineering applications are an essential component of understanding the development of new tissues and studying the biochemical interactions between cells and their environment. A bioreactor is typically designed to mimic physiological, environmental, and mechanical stimuli that occur in vivo, and bioreactors are generally created for a specific application, such as for studying 3-dimensional tissues or dynamic fluid flow in 1-dimensional cell monolayers. The leading cause of death in the United States is coronary artery disease, which is treated with bypass graft surgery using a left internal mammary artery or human saphenous vein as the graft. Since human saphenous vein grafts often fail, investigating vascular function as a whole will help to understand more about the method of graft failure. A bioreactor system to study vascular function was successfully developed using the application of endothelial cells under shear stress in a microfluidic slide. The temperature control and diffusion rate of CO2 were recorded inside the bioreactor to confirm the system could stay within a temperature range of 37ºC +/- 0.5ºC and a CO2 concentration between 56,000 ppm and 45,000 ppm. Also, a physiological level of shear stress was determined to be feasible with the peristaltic pump. The performance characteristics of the bioreactor were analyzed, and the apparatus was determined to be successful in generating physiological relevant conditions. Then, human umbilical vein endothelial cells were exposed to both static conditions and venous shear stress conditions for up to four days in an IBIDI® microfluidic chamber. The cell morphology, alignment, and elongation were also evaluated. The cells stayed viable during the duration of all of the dynamic flow experiments, and the cells showed evidence of cell division. The cells were also more aligned and elongated towards the direction of flow for the 48 and 72 hour flow experiments compared to th (open full item for complete abstract)

Committee: Robert Wilkens (Advisor); Carissa Krane (Advisor); Kristen Comfort (Committee Member) Subjects: Biology; Biomedical Engineering; Biomedical Research; Chemical Engineering; Engineering

Master of Fine Arts, The Ohio State University, 2011, Industrial, Interior Visual Communication Design

Nowadays, when we talk about sustainability or environmentally friendly practices, we try to convince groups or individuals to be good citizens or good people. Especially young people do not care deeply about pursuing an environmentally conscious lifestyle if it requires an effort on their part. What if one uses fun to influence (i.e., motivate and inform) students about sustainability in their daily life? Would this approach be more successful in changing their behavior? Can sustainability even be considered to be fun? As we already know, behavior change requires motivation and fun could be used as a motivational factor. Proposing that we need to develop programs and concepts that make a sustainable lifestyle fun instead of perceiving it as a negative influence on our quality of life provides new opportunities for projects and interventions. When we make sustainable practices fun, the likelihood to adapt such a new behavior increases. Behavioral change results from a combination of three factors, namely, awareness, information and motivation, which is the most important starting point for fun. This thesis addresses the difficulties in informing and motivating students to choose a sustainable lifestyle by focusing on their consumer behavior. With a fun and playful application, the user should be able to learn and inform herself or himself about a sustainable lifestyle and be motivated to integrate it into her or his own daily life. By offering multiple choices of action as well as the opportunity to be and act as a part of a whole group (i.e., collective action), competition and therefore motivation should be raised. This results from the idea that fun can be experienced both individually or as a group. Design Research is the main tool to develop this informational and motivational application. Research on the target group, in combination with existing case studies in design and the psychological aspects of human decision making, will lead to a design application. T (open full item for complete abstract)

Committee: Paul Nini J (Committee Chair); Elizabeth Sanders B.-N. (Committee Member); Carolina Gill (Committee Member) Subjects: Demographics; Design; Fine Arts; Sustainability; Systems Design