Master of Science in Exercise and Health Studies, Miami University, 2014, Exercise and Health Studies

The purposes of this investigation were to determine if proxies for muscle fiber composition and anthropometric measurements can predict systolic (SBP) and diastolic blood pressure (DBP), pulse pressure(PP), and mean arterial pressure (MAP). We studied 370 Division I Male and Female Athletes from various sports. Multiple regressions were run to predict blood pressure from anthropometric variables and proxies for fiber type. SBP included Neck circumference, Arm span, and MaxVi (.663;43.4%); DBP included BMI, Arm Length, and Neck Circumference (.298;8.9%); PP included peak force, height, MaxVi, and Neck Circumference (.639;40.2%); and MAP included BMI and Neck Circumference (.458;20.5%). Blood pressure exists on a normal curve, and because natural characteristics like fiber type and anthropometric-characteristics affect blood pressure, their influence on normal homeostatic blood pressure should be considered in the determination of pathology from normal physiology and the evaluation of treatment options.

Doctor of Philosophy, The Ohio State University, 2011, Food Science and Technology

Lycopene is a major carotenoid in tomatoes and epidemiological studies suggest that consumption of food rich in carotenoids lowers the risk of developing certain types of cancer and chronic diseases. However, very little is known about its fate in tomato products subjected to a range of combined pressure-temperature (P-T) treatments. Likewise, little is known about the pressure-temperature uniformity during combined P-T processing. This study was conducted to investigate the effect of pressure-thermal treatments (0.1, 500, 600 & 700 MPa; 30-100 deg. C, different time intervals) on post processing extractability, isomerization, bioaccessibility and storage stability of lycopene in tomato juice. Finally, a study was conducted to evaluate the feasibility of using a chemical M-2 (4-Hydroxy-5-methyl-3(2H)-furanone) as a potential marker for understanding combined P-T process non-uniformity. Combined pressure-thermal treatments (Pressure Assisted Thermal Processing (PATP), High Pressure Processing (HPP)) resulted in up to 12% increase in lycopene extractability over thermally processed (TP) and unprocessed control tomato juice. In addition, all-trans lycopene showed stability to isomerization in tomato juice samples subjected to HPP, PATP and TP. The post processing retention of β-carotene was a function of processing time, temperature, pressure, cultivar used and type of juice (raw vs. hot break). During storage, lycopene degradation varied as a function of cultivar, processing method, storage temperature, and time. Increase in storage temperatures also increased degradation. Among the stored juices, HPP processed juice showed the least lycopene degradation. Also, HPP and PATP juice samples better retained lycopene cis isomers and color during storage. β-carotene showed good stability in the processed samples during storage. A two-step first order equation was used to predict the changes in lycopene concentration over the course of storage. The processed juice sam (open full item for complete abstract)

Master of Science in Engineering, University of Akron, 2008, Biomedical Engineering

In critical care, a fluid-filled catheter transducer system is commonly used to continuously monitor blood pressure. The fluid-filled catheter transducer system, as a first approximation, behaves as a second order dynamic system. The dynamic characteristics of the system are affected by variations in assembly technique and time dependent changes in the system, often resulting in distortion and inaccurate measurements. A previous simulation study employed a counter pressure source in tandem with the transducer. The counter pressure generated minimized the fluid flow in the pressure monitoring system. When the flow in the system was zero the counter pressure generated closely approximated the true blood pressure. The current study developed a real-time technique to generate accurate and dependable counter pressure. To validate this technique, one experimental model (second order dynamic system) and two simulation models (second order dynamic system and fourth order dynamic system) of catheter transducer system were developed and tested under varying system conditions. The real-time technique developed, successfully reproduced the true blood pressure waveforms, regardless of variations in the system characteristics and changes in the system over time.

Master of Science, The Ohio State University, 1963, Graduate School

Master of Science in Mechanical Engineering (MSME), Wright State University, 2016, Mechanical Engineering

Improvements in turbine design methods have resulted in the development of blade profiles with both high lift and good Reynolds lapse characteristics. An increase in aerodynamic loading of blades in the low pressure turbine section of aircraft gas turbine engines has the potential to reduce engine weight or increase power extraction. Increased blade loading means larger pressure gradients and increased secondary losses near the endwall. Prior work has emphasized the importance of reducing these losses if highly loaded blades are to be utilized. The present study analyzes the secondary flow field of the front-loaded low-pressure turbine blade designated L2F with and without blade profile contouring at the junction of the blade and endwall. The current work explores the loss production mechanisms inside the low pressure turbine cascade. Stereoscopic particle image velocimetry data, total pressure loss data and oil flow visualization are used to describe the secondary flow field. The flow is analyzed in terms of total pressure loss, vorticity, Q-Criterion, Reynolds' stresses, turbulence intensity and turbulence production. The flow description is then expanded upon using an Implicit Large Eddy Simulation of the flow field. The RANS momentum equations contain terms with static pressure derivatives. With some manipulation these equations can be rearranged to form an equation for the change in total pressure along a streamline as a function of velocity only. After simplifying for the flow field in question the equation can be interpreted as the total pressure transport along a streamline. A comparison of the total pressure transport calculated from the velocity components and the total pressure loss is presented and discussed. Peak values of total pressure transport overlap peak values of total pressure loss through and downstream of the passage suggesting that total pressure transport is a useful tool for localizing and predicting loss origins and loss development using (open full item for complete abstract)

Master of Science (MS), Bowling Green State University, 2014, Communication Disorders/Speech-Language Pathology

The most frequently used method to estimate subglottal pressure noninvasively is to have a person smoothly utter CVCV; strings such that the subglottal pressure remains nearly constant throughout the utterance of the string, as in smoothly saying /p:i:p:i:p:i:/, and an oral pressure transducer is used to estimate the subglottal air pressure during the vowels by measuring the oral pressures during the consonants. The current investigation sought to determine the accuracy of estimates of subglottal pressure for various conditions, namely, whether or not the subjects are trained in the use of a standard utterance, increasing syllable rate, using a voiced /b/ instead of a voiceless /p/ initial syllable, adding a lip or velar leak, or using a two syllable production instead of a single syllable production. 10 subjects (5 males and 5 females) volunteered for this study (results for 3 males and 3 females are reported here). The subglottal pressure was estimated from the oral pressure during lip occlusion, and the syllable rate and lip closed quotient (the duration the lips are closed divided by the syllable duration) were obtained for all subjects. Lip leak, velar leak, and lack of time to equilibrate air pressure throughout the airway caused estimates of subglottal pressure to be inaccurate. A wide range of syllable rates provided relatively accurate results. In addition, the use of the voiced initial consonant /b/ and the two-syllable word "peeper" appeared to create acceptable estimates of subglottal pressure from oral pressure. Training improved the consistency of the oral pressure profiles and thus the assurance in estimating the subglottal pressure. Numerous pressure profile shapes during lip occlusion are discussed.

MS, University of Cincinnati, 2009, Allied Health Sciences : Nutrition

Purpose: To assess the change in the glycemic index of the diets of teenagers with hypertension or pre-hypertension who received formal nutrition counseling as part of a 3-month intervention to lower blood pressure. Subjects: A sub-set of the participants' data as reported by Couch et al. (12) was used. Participants were adolescents between the ages of 11-19 years with diagnosed pre-hypertension and Stage 1 hypertension (n=45). Study Design: Participants were randomly assigned to a behavioral nutrition intervention focused on the DASH diet (n=23) or Routine Care (RC) (n=23). Methods: Dietary glycemic index (DGI) and dietary glycemic load (DGL) were calculated for each treatment group for food items obtained from three 24-hour recalls collected at baseline and 3 months (post-intervention). Change scores for dietary glycemic index, dietary glycemic load, systolic blood pressure and diastolic blood pressure were calculated by subtracting baseline values from post-treatment values. Results: Neither the DASH nor the RC treatment significantly reduced DGI or DGL. There was no detectable association between change in DGI or DGL for all participants or by intervention group and change in systolic blood pressure or diastolic blood pressure. Conclusion: Based on these findings, counseling on a DASH type diet did not significantly modify DGI or DGL. Further, change in DGI and DGL was not associated with change in blood pressure in this study. These results suggest that the effects of the DASH intervention on blood pressure in this study were mediated by some component of the DASH diet other than DGI or DGL.

Doctor of Philosophy in Engineering, University of Toledo, 2009, Mechanical Engineering

Working prototypes of a Hydraulic Hybrid Vehicle (HHV) are already under testing and investigation. One of the problems reported from testing is that the noise levels emitted by the hydraulic system are not acceptable. Therefore, there is a need to perform extensive research to improve the HHV systems in terms of noise and performance. The pump is the main source of noise in HHV systems. However, the lack of space, the high pressure and the dynamics of components within the pump have prevented either direct observation or measurement of potential noise causing mechanisms within the pump structure. As a result, there are several theories as to the source of the noise from the pump units but little concrete information to further isolate and reduce the noise generation.Currently, the industry use “cut and try” methods in order to study the noise issue. This necessities the development of a theoretical tool that will enable us to avoid the costly (time and money) cut and try procedure already employed in the current efforts. This work creates a dynamic and geometric model of a bent axis pump for this purpose. Elements of the model include finding the variation of pressure, flow rate, and dynamic forces acting on the pump components and case as a function of angular rotations of both the main shaft and the yoke. The model was constructed using MathematicaTM” software and verified against test data. In turn, this study identifies and analyzes the dominant forces in both the time and frequency domains. The solution of the theoretical model using MathematicaTM is verified by a dynamic model created using ADAMS/View software. The kinematic model was able to predict the variations of the angular velocities and accelerations and the velocities and the accelerations of the center of gravity of the entire pump's parts starting from the main shaft up to the yoke. This work presents all equations necessary to solve for the piston pressure and pump flow rate as a function of main (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2007, Polymer Science

One of the biggest challenges in solid state physics today is understanding the nature of the glass transition. Dynamic studies are critical in solving some of the problems in the field. Until recently, investigations of dynamics in glass formers were mostly carried out as a function of temperature. However, with the advancements in experimental techniques and methods, the interest towards using pressure as an additional experimental variable increased. The advantages of pressure over temperature are two-fold: First, it only alters the density of the system, whereas temperature changes both the thermal energy and the density, and secondly, one can achieve significant density changes (~20%) with pressure, whereas temperature creates smaller density changes (~5%). These advantages let researchers make direct comparisons of the results with glass transition models (i.e. free volume ideas). The dynamics in the frequency range between 1 GHz and 5 THz (fast dynamics), are thought to have a crucial role. Crystals in this frequency range have a Debye-like density of vibrational states. Glasses, however, have two extra contributions when compared to crystalline structures: (i) an anharmonic relaxation-like contribution that appears as a quasielastic scattering (QES) and (ii) a harmonic vibrational contribution, which shows up as the boson peak (BP) in light and neutron scattering spectra. It has also been shown experimentally that fast dynamics in glasses are strongly correlated with the temperature dependence of structural relaxation.In this dissertation the influence of pressure on fast dynamics in polyisobutylene, polyisoprene and low molecular weight polystyrene is investigated using inelastic light, neutron and X-ray scattering techniques. The results are compared to the predictions of the existing models.The results for all polymers studied showed that the boson peak shifts more strongly than sound modes, suggesting that the variations cannot be fully described by the (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2007, Counseling Psychology

Researchers have often stated that when examining the development of eating disorders, it is fruitful to take a multi-dimensional approach in order to identify the role of several contributing factors. Unfortunately, not only has this framework been used all too rarely in the general research on eating disorders, it has hardly ever been used when looking at the development of disordered eating among athletes. To this end, relationships among self-reported symptoms of disordered eating, body image dissatisfaction, and two types of perceived pressure for thinness (social and athletic) were investigated in a sample of 206 women collegiate athletes from two Division I schools, representing 12 different sports. A series of regression analyses, and a test of mediation, were used to analyze the data. It was hypothesized that body image dissatisfaction and perceived pressure for thinness would each account for a significant amount of variance in symptoms of disordered eating, and that body image dissatisfaction would mediate the relationship between both kinds of perceived pressure for thinness and disordered eating. Support was garnered for several of the hypotheses. Specifically, the independent variables of body image dissatisfaction, social pressure for thinness, and athletic pressure for thinness each uniquely accounted for variance in disordered eating. Somewhat differing from the hypothesized relationship, body image dissatisfaction functioned as a partial mediator, rather than a full mediator, in the relationship between social pressure for thinness and disordered eating, as well as in the relationship between athletic pressure for thinness and disordered eating. Additional exploratory analyses indicated that athletic pressure did not account for additional variance in disordered eating above and beyond that accounted for by social pressure for thinness. Further, significant differences emerged on the variables of bulimia and athletic pressure for thinness when comp (open full item for complete abstract)

DNP, Walsh University, 2024, Nursing

Hypertension (HTN) is one of the most diagnosed conditions and is increasing in prevalence at an extreme rate. Although evidence-based recommendations include self-measured blood pressure (SMBP) twice daily, many older adults do not monitor their blood pressure outside of the clinic setting. Consistent education from healthcare professionals to patients on how to correctly measure blood pressure and address other risk factors of hypertension is lacking. This research study was designed to implement and evaluate the effectiveness of an SMBP training program for registered nurses (RNs) providing case management support to community-based older adults with essential hypertension in a Managed Care Organization (MCO) across Wisconsin. RN case managers completed a learning module and their hypertension management knowledge was measured at three points, pre-intervention, immediately post-intervention, and one-month post-intervention. Results were then compared via RM-ANOVA. A retrospective review of patient charts was also completed to determine if there was an increase in the patient recorded frequency of SMBP following the RN case manager training and compared via independent t-tests. The RN case managers' hypertension management knowledge increased significantly following education, with a slight decrease in scores over time. Retrospective chart reviews revealed that the frequency of documented patient blood pressure self-measurements increased significantly following RN case manager education. Implementing an evidence-based SMBP training program for RN case managers is a successful intervention to support the management of essential hypertension in community-based older adults.

MS, University of Cincinnati, 2024, Engineering and Applied Science: Mechanical Engineering

This study proposes a novel approach to intracranial pressure (ICP) analysis. ICP is the pressure exerted by fluids and tissue inside of the brain and reveals crucial insights regarding a patient's physiological state after undergoing traumatic brain injury (TBI). ICP waveform morphological analysis can provide clinicians with information regarding a patient's health and facilitate proactive intervention and inhibit the development of secondary pathologies such as cerebral edema (swelling), ischemia (lack of blood to the brain), vascular injuries, neurological dysfunction, and cognitive/behavioral changes. By integrating arterial blood pressure (ABP) and electrocardiogram (ECG) data from patients who have undergone TBI this method aims to enhance the analysis of not just ICP waveform morphology but cross-signal morphological features. The proposed methodology was evaluated on ten patients and their respective ICP, ABP, and ECG data; it involved three key steps: 1) multimodal signal pre-processing alongside manual labeling of ICP waveform morphologies to train a base support vector machine (SVM) morphological classifier. 2) The use of semi-supervised learning leveraging a subject matter expert (SME) to further train the SVM ICP waveform morphological classifier and augment its training data set on all ten patients to assign incoming pre-processed ICP waveforms with a morphology label. A SME used the posterior probability of the SVM machine learning model to aid the algorithm in adapting to new and unseen ICP waveform morphologies that were not present in the initial manually labeled SVM training data set. 3) The utilization of dynamic time warping barycenter averaging (DBA) to produce representative averages (centroids) of ICP waveforms present in the SVM training data set and derivative dynamic time warping (DDTW)-driven subpeak identification to map subpeaks from DBA generated centroid templates with SME assigned ground truth subpeak(s) to incoming SVM clas (open full item for complete abstract)

Master of Science, University of Akron, 2023, Mechanical Engineering

All-solid-state lithium batteries (ASSLBs) using argyrodite electrolyte materials have shown promise for applications in electric vehicles (EVs). However, understanding the effects of processing parameters on the ionic conductivity of these electrolytes and performance of full solid-state cells is crucial for optimizing battery performance and manufacturing methods. This study investigates the influence of electrolyte operating temperature, operating pressure, pelletization pressure, and pelletizing temperature on the ionic conductivity of Li6PS5Cl0.5Br0.5 argyrodite electrolyte (AmpceraTM, D50=10 µm) as well as how pelletizing temperature impacts a full solid-state cell's cycle life. A specially designed test cell is employed for the experimental measurements, allowing for controlled pelletization and testing within the same tooling. The results demonstrate the significant impact of the four parame-ters on the ionic conductivity of the argyrodite electrolyte. The electrolyte operating temperature has a more pronounced effect than operating pressure, and pelletizing temperature exerts a greater influence than pelletizing pressure. This study provides results that aid in understanding the interplay between these parameters and achieving desired conductivity values. It also establishes a baseline for the maximum pelletizing temperature before undesirable degradation of electrolyte occurs. By manipulating the pelletizing pressure, operating pressure, and pelletizing temperature, battery engineers can achieve the desired conductivity for specific applications. The findings emphasize the need to consider operating conditions to ensure satisfactory low-temperature performance, particularly for EVs. Overall, this study provides valuable insights into processing and operating conditions for ASSLBs utilizing Li6PS5Cl0.5Br0.5 argyrodite electrolyte.

Doctor of Nursing Practice, Mount St. Joseph University , 2021, Department of Nursing

Remote home blood pressure (BP) monitoring has the potential to improve patient engagement and adherence with the prescribed treatment plan for managing hypertension. This DNP project examined the effects of daily remote BP measurement using transmission of biometric data through a Bluetooth-equipped device paired to participants' smartphones. Twelve adults, with an age range of 37 to 69 years, completed four weeks of daily BP measurements and communicated via text, telephone call, or video visit with care team members to discuss the plan of care and address any concerns. A Wilcoxon signed-ranks test was performed to determine the magnitude of difference between the week 1 and week 4 systolic and diastolic BP measurements. The results revealed Week 4 systolic BPs (M = 127, SD = 12.48) were significantly lower than the Week 1 systolic BPs (M = 136, SD = 12.48), W = -2, p = .004 and the Week 4 diastolic BPs (M = 82, SD = 10.97) were significantly lower than the Week 1 diastolic BPs (M = 89, SD = 9.92), W = -4, p = .006. This average systolic decrease of 9 mmHg and average diastolic decrease of 7 mmHg indicated success in lowering BP within a four-week timeframe. The clinical management of a chronic condition such as hypertension is a long-term process, but the findings of this DNP project supported the empirical evidence showing that remote BP monitoring improves patient outcomes.

BS, Kent State University, 2019, College of Education, Health and Human Services / School of Health Sciences

Caffeine consumption prior to resistance exercise has demonstrated significant increases in maximal strength in resistance-trained individuals, along with concomitant increases in heart rate (HR) and blood pressure (BP). Therefore, the purpose of the present study was to examine the effects of caffeine (4mg/kg) alone or in conjunction with acute resistance exercise in resistance-trained women on resistance exercise performance and cardiovascular hemodynamics. The acute bout of resistance exercise consisted of two sets of 10 repetitions at 75% 1 repetition maximum (1RM) for the squat and bench press, and one set to failure at 70% 1RM for both resistance exercises. Performance variables included the total load lifted, as well as the number of repetitions completed. Hemodynamic variables included HR, systolic and diastolic BP, mean arterial pressure, and pulse pressure. Measurements were taken at rest (Rest1), 45 minutes after consumption of the caffeine or placebo (Rest2), immediately post exercise (Rec1), and 10-minutes post exercise (Rec2). Paired samples t-tests were used to evaluate differences in total load, and the total number of repetitions performed during set 3. A 2 x 4 repeated measures ANOVA was used to assess the effects of condition (caffeine vs placebo) across the time (Rest1, Rest2, Rec1, Rec2) with a Bonferroni correction. Eight resistance-trained women (mean±SD: 23±3 yrs) completed the study. There were no significant differences between conditions for any performance variable. However, there was a significant (p=0.001) main effect of time for HR, such that it was elevated at Rec1 and Rec2, compared to Rest1 and Rest2. There were no significant interactions of main effects for systolic or diastolic BP. There was a significant interaction (p=0.04) for mean arterial pressure such that following caffeine consumption it was elevated at Rest2 compared to Rest1, and was different than Rest2 following the placebo. There was also no interaction or ma (open full item for complete abstract)

Master of Science, The Ohio State University, 2019, Biomedical Engineering

Low back pain affects nearly 84% of people at some point in their life, yet the underlying mechanisms are not completely understood. Intervertebral disc disease is commonly associated with low back pain and features a decrease in proteoglycan content in the intervertebral disc (IVD). This decrease in proteoglycan content is directly tied to a drop in osmotic pressure and ion concentration, as the proteoglycans, specifically aggrecan, attract ions in solution and resist the compression of the disc. Additionally, the change in pressure in the disc due to diurnal activity has been proven to affect the behavior of disc cells, although the true change in osmotic pressure and ion concentration is still unknown. This study aimed to measure the diurnal change in osmotic pressure and ion concentration in a healthy disc by first verifying the use of a needle micro-osmometer in nucleus pulposus (NP) tissue plugs and then in intact discs. Flux measurements using the micro-osmometer were taken in tissue plugs equilibrated in a range of PEG solutions to determine osmotic pressure and ion concentration. The process was then repeated in intact IVDs that were mechanically loaded in a diurnal compression cycle. Osmometer flux measurements in NP tissue had a significant relationship with both osmotic pressure and ion concentration, as did intact motion segments. Variation in motion segment measurements were high, restricting use as a predictive tool. The needle micro-osmometer was proven to measure osmotic pressure and ion concentration in both intact IVDs and tissue plugs, although additional testing is needed to reduce error and enhance repeatability in measurements.

Master of Science, The Ohio State University, 2019, Chemical Engineering

Chemical looping technologies can be used as an advanced reforming technology, capable of efficiently generating syngas to serve as a feedstock in a variety of important chemical industries. The pressure of the syngas feedstock to downstream chemical synthesis reactors is an important characteristic that can dictate the products and overall plant economics. While most chemical synthesis reactors, such as Fischer-Tropsch and methanol synthesis reactors, operate at high pressures, most chemical looping reforming studies have been conducted under atmospheric conditions. The high thermodynamic yields from the atmospheric chemical looping reformer run counter to the high conversion of the pressurized downstream reactors. Therefore, this study seeks to quantify the impact of the operating conditions of the chemical looping reformer on the overall system yields. Specifically, The Ohio State University methane to syngas process is analyzed, which uses a cocurrent moving bed fuel/reducer reactor and a fluidized bed air/combustor reactor. The syngas generation results are compared under a variety of operating conditions with the pressure varied between 1 and 30 atm. Initial studies are compared in an isothermal analysis to study the effect of variables, independent of operating temperature. The resulting isothermal analysis is used to guide an adiabatic reactor configuration in an attempt to develop an autothermal chemical looping system. The gas feedstocks, solid feedstocks, operating temperature, feedstock preheating conditions, and system pressure are all analyzed. The results of the autothermal chemical looping system are then integrated into a ~5000 MWth natural gas to liquid fuels plant, in which a chemical looping reformer replaces an autothermal reformer reactor. The study shows that operation of the chemical looping process allows for equivalent syngas yield compared to the autothermal reformer with a 7-13% reduction in natural gas feedstock. Lastly, a novel operatin (open full item for complete abstract)

Master of Science, The Ohio State University, 2018, Food Science and Technology

Processors of American pickles utilize fermentation or direct acidification in conjunction with thermal processing as a part of their preservation step. Health conscious consumers are demanding for clean-labeled products that are minimally processed with reduced salt/sugar and free from synthetic preservatives. This has prompted the pickle manufactures to investigate clean food processing methods such as high pressure processing (HPP) and other minimally processed methods with reduced thermal impact. Our hypothesis is that by reducing thermal exposure, combined pressure-thermal treatment can help to better retain quality attributes of selected acidified vegetable pickles over 30 days storage at 25oC. The objective of this research were to evaluate the heat of compression of pickling liquid with various solute concentration as well as vegetables subjected to two different acidification pretreatment approaches (2) assess the quality changes of acidified vegetables treated by various pressure (600 MPa)-thermal (45-65oC) combinations with and without thermal blanching. First set of experiments investigated the heat of compression values of pickling solution with varying solute concentration as well as pickling vegetables subjected to two different pre-treatments. Subsequently samples were pressure treated in a pilot scale high-pressure processor at 600 MPa, 45° or 65°C for 5 min and stored at ambient temperature for 30 days. Quality analyses included texture, enzyme activity, color, pH and °Brix. Solute concentration, initial temperatures and vegetable pretreatments significantly influenced heat of compression values of pickling liquid and vegetables. At 25oC, heat of iii compression values of the pickling liquid varied as a function of varying solute concentration (p<0.05). On the other hand, thermal effect dominated over solute concentration at 60oC. Both methods of acidification (thermal blanching and overnight soaking) of vegetables influenced heat of compressio (open full item for complete abstract)

Master of Science, University of Toledo, 0, Mechanical Engineering

This study focuses on the effects of unilateral sinusoidal-shaped polyps on air pressure on the surface of a model of human vocal folds. Both experimental and numerical methods were used to obtain air pressures on the models. The vocal fold model used for this research is a previously developed model called M6, which is an asymmetric, three-dimensional physical model of the larynx. M6 is 7.5 times larger than life size and has a symmetrical sinusoidal glottal surface profile with an asymmetrical upstream configuration following the anatomy of the trachea and inferior larynx. The glottis has a maximum glottal width of 0.16 cm (real life size) at the mid-coronal section. To capture the e¿ects of polyp lesions, two sessile polyp-like “growths” - spherical caps - of height 0.06 cm and 0.14 cm (real life size) were placed unilaterally. Air pressure was measured at three rows of 14 pressure taps, located in the inferior to superior parts on the vocal fold surface at locations of the anterior (1/4), middle (1/2), and posterior (3/4) of the anterior-posterior span (1.2 cm). Three glottal angles (10° convergent, 0° uniform, and 10° divergent), three polyp conditions (no polyp, the protrusion of 0.06 cm, and the protrusion of 0.14 cm) and a range of transglottal pressures were used to obtain air pressure distributions. The lesions were placed in the medial center of the vocal fold surface (anteriorly-posteriorly and inferiorly-superiorly). For each con¿guration, transglottal pressures of 0.0981, 0.491, 1.742 and 2.453 kPa (i.e., 1, 5, 15 and 25 cm H2O) were used. All the cases were considered with the presence of the arytenoid cartilage in the posterior position (with no airflow through the posterior glottis). The empirical pressures were compared to computational results obtained using the CFD software package ANSYS FLUENT and assuming laminar flow conditions. The results indicated that vocal folds' pressure distributions varied according to the glottal angle and the presen (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2018, Civil Engineering

Bridge local scour has long been identified as the most critical cause to bridge failures. Countermeasures that are commonly used nowadays still have disadvantages to some extent. This work is among one of the ongoing efforts to explore reliable alternatives. Inspired by the streamlined body of boxfish and blue shark, this study introduced streamlining features to the bridge piers in order to reduce the erosive forces locally. Based on the excess shear stress criteria, the Reynolds-Averaged Navier Stokes (RANS) numerical model was employed to optimize the streamlined features through parametric studies. The maximum bed shear stress around the optimal streamlined pier was shown to be reduced by ~34% as compared to that around a non-streamlined pier. Further simulation using the advanced Detached Eddy Simulation (DES) model revealed that the streamlined pier also helped reduce the locally turbulence dynamics, which played a significant role in local scour. A set of small-scale flume tests were then conducted in the laboratory to characterize the flow physics and scour behavior of uniform Ottawa sand around piers with various streamlined extents. The experimental results further confirmed the effectiveness of pier streamlining in scour reduction. The maximum scour depth around the streamlined pier was reduced by ~66% as compared to that around a non-streamlined pier. Through monitoring the pore pressure response within sand, the role of vortex-induced excess pore pressure that plays in the scour mechanism was discussed. The vortex-induced excess pore pressure also helped to partially account for an interestingly counterintuitive observation from an independent experiment: the local scour resistance was a slightly decreasing function of the granular bulk density. Finally, a CFD-DEM (Discrete Element Model) two-way coupled model was established to simulate the scour behavior of uniform spherical particles around an oblong pier. The two-phase model successfully captured t (open full item for complete abstract)