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Articles 1 - 30 of 315

Full-Text Articles in Mechanical Engineering

An Iterative Size Effect Model Of Surface Generation In Finish Machining, Ian S. Brown, Julius M. Schoop Jul 2020

An Iterative Size Effect Model Of Surface Generation In Finish Machining, Ian S. Brown, Julius M. Schoop

Mechanical Engineering Faculty Publications

In this work, a geometric model for surface generation of finish machining was developed in MATLAB, and subsequently verified by experimental surface roughness data gathered from turning tests in Ti-6Al4V. The present model predicts the behavior of surface roughness at multiple length scales, depending on feed, nose radius, tool edge radius, machine tool error, and material-dependent parameters—in particular, the minimum effective rake angle. Experimental tests were conducted on a commercial lathe with slightly modified conventional tooling to provide relevant results. Additionally, the model-predicted roughness was compared against pedigreed surface roughness data from previous efforts that included materials 51CrV4 and ...


Characterization And Modeling Of Surface Roughness And Burr Formation In Slot Milling Of Polycarbonate, David Adeniji, Julius M. Schoop, Shehan Gunawardena, Craig Hanson, Muhammad Jahan Jun 2020

Characterization And Modeling Of Surface Roughness And Burr Formation In Slot Milling Of Polycarbonate, David Adeniji, Julius M. Schoop, Shehan Gunawardena, Craig Hanson, Muhammad Jahan

Mechanical Engineering Faculty Publications

Thermoplastic materials hold great promise for next-generation engineered and sustainable plastics and composites. However, due to their thermoplastic nature and viscoplastic material response, it is difficult to predict the properties of surfaces generated by machining. This is especially problematic in micro-channel machining, where burr formation and excessive surface roughness lead to poor component-surface integrity. This study attempts to model the influence of size effects, which occur due to the finite sharpness of any cutting tool, on surface finish and burr formation during micro-milling of an important thermoplastic material, polycarbonate. Experimental results show that the depth of cut does not affect ...


Numerical Analyses And Integration Of Split Lot Sizing Using Lean Benchmark Model For Small Lot Manufacturing In High Mix Low Volume Production, Omkar Bhosale Jan 2020

Numerical Analyses And Integration Of Split Lot Sizing Using Lean Benchmark Model For Small Lot Manufacturing In High Mix Low Volume Production, Omkar Bhosale

Theses and Dissertations--Manufacturing Systems Engineering

As the global demand for automobiles has increased rapidly over the last fifty years, customers have become more particular about the characteristics of the autos they want. This change in demand, in part has pushed manufacturing to become more flexible and created a demand for alternative, more efficient processes like the High Mix Low Volume (HMLV) production of vehicles. During HMLV, manufacturers create production lot sizes and schedule to synchronize the production processes to meet customer demand on time. The demand for the automobile parts may not be uniform or parts may not be consumed by the customer immediately, Due ...


Numerical And Experimental Studies Of Blocked Force Determination On An Offset Interface For Plate And Shell Structures And Duct Acoustic Systems, Keyu Chen Jan 2020

Numerical And Experimental Studies Of Blocked Force Determination On An Offset Interface For Plate And Shell Structures And Duct Acoustic Systems, Keyu Chen

Theses and Dissertations--Mechanical Engineering

Blocked force determination is an alternative to the more routine method of inverse force determination using classical transfer path analysis. One advantage of determining blocked forces is that there is no need for the source to be detached or isolated from the system. Another advantage is that calculated blocked forces are appropriate when modifications are made on the receiver side of the interface. This insures that the blocked forces are suitable for utilization in analysis models where receiver system modifications are considered. Difficulties in using the approach arise when interface locations are difficult to instrument. This thesis demonstrates that blocked ...


Atv Dynamics And Pediatric Rider Safety, James T. Auxier Ii Jan 2020

Atv Dynamics And Pediatric Rider Safety, James T. Auxier Ii

Theses and Dissertations--Biomedical Engineering

It has been observed through numerous academic and governmental agency studies that pediatric all-terrain vehicle ridership carries significant risk of injury and death. While no doubt valuable to safety, the post-hoc approach employed in these studies does little to explain the why and how behind the risk factors. Furthermore, there has been no prolonged, widespread, organized, and concerted effort to reconstruct and catalog the details and causes of the large (20,000+) number of ATV-related injuries that occur each year as has been done for road-based motor vehicle accidents. This dissertation takes the opposite approach from a meta-analysis and instead ...


Effects Of A Hip Orthosis On Lumbopelvic Coordination In Individuals With And Without Low Back Pain, Colin Drury Jan 2020

Effects Of A Hip Orthosis On Lumbopelvic Coordination In Individuals With And Without Low Back Pain, Colin Drury

Theses and Dissertations--Biomedical Engineering

Individuals with low back pain (LBP) demonstrate an abnormal lumbopelvic coordination compared to back-healthy individuals. This abnormal coordination presents itself as a reduction in lumbar contribution and an increase in pelvic contribution to trunk motion. This study investigated the ability of a hip orthosis to correct such an abnormal lumbo-pelvic coordination by restricting pelvic rotation and, as a result, increasing lumbar contributions. The effects of the hip orthosis on the magnitude and timing characteristics of lumbopelvic coordination were investigated in 20 patients with LBP and 20 asymptomatic controls. The orthosis significantly increased lumbar contributions by 11%, 5.42%, 4.84 ...


Coarse-Grained Dynamically Accurate Simulations Of Ionic Liquids At Vacuum-Interface, Tyler D. Stoffel Jan 2020

Coarse-Grained Dynamically Accurate Simulations Of Ionic Liquids At Vacuum-Interface, Tyler D. Stoffel

Theses and Dissertations--Mechanical Engineering

Ionic liquids, possessing improved properties in many areas of technical application, are excellent candidates as components in development of next-generation technology, including ultra-high energy batteries. If they are thus applied, however, extensive interfacial analysis of any selected ionic configuration will likely be required. Molecular dynamics (MD) provides an advantageous route by which this may be accomplished, but can fall short in observing some phenomena only present at larger time/length scales than it can simulate. Often times this is approached by coarse-graining (CG), with which scope of simulation can be significantly increased. However, coarse-grained MD systems are generally known to ...


Safety Concepts For Every Ride: A Statistical Ensemble Simulation To Mitigate Rotational Falls In Eventing Cross Country, Shannon Wood Jan 2020

Safety Concepts For Every Ride: A Statistical Ensemble Simulation To Mitigate Rotational Falls In Eventing Cross Country, Shannon Wood

Theses and Dissertations--Mechanical Engineering

Rotational falls are the leading cause of death and serious injury in the equestrian sport of eventing. Previous studies to develop safety devices used physical models representing one or at most several physical situations leading to different designs and no common understanding. In this thesis, a statistical ensemble model is developed and applied to generate and evaluate 10,000 different situations that might potentially lead to rotational falls. For accurate statistical representation of the horse and rider inertia distributions, measurements of over 400 training or competing horses and riders were recorded and incorporated. Video was recorded of 218 total competitors ...


The Effect Of Cutting Edge Geometry, Nose Radius And Feed On Surface Integrity In Finish Turning Of Ti-6al4v, Ian S. Brown, Julius M. Schoop Jan 2020

The Effect Of Cutting Edge Geometry, Nose Radius And Feed On Surface Integrity In Finish Turning Of Ti-6al4v, Ian S. Brown, Julius M. Schoop

Mechanical Engineering Faculty Publications

While the respective effects of nose radius, feed and cutting edge geometry on surface integrity have each been studied at depth, coupling between these effects is not yet sufficiently understood. Recent studies have clearly established that cutting edge micro-geometries may not only have positive effects on tool-life, but can also be used to tailor surface integrity characteristics, such as surface roughness and near-surface severe plastic deformation. To further a more fundamental understanding of the effects of cutting edge micro-geometries on surface integrity, experimental turning data was generated for a varied range of cutting tool geometries and feeds. Scanning laser interferometry ...


Modeling Thin Fluid Film On A Rotary Bell, Mark Doerre Jan 2020

Modeling Thin Fluid Film On A Rotary Bell, Mark Doerre

Theses and Dissertations--Mechanical Engineering

A component of the mission in the Institute of Research for Technology Development at the University of Kentucky is advancing research and development and bringing it to the factory floor for continuous improvement. This dissertation delves into the art and science of rotational fluid mechanics in the context of rotary bell atomizers. One outcome proves that an approximation for calculating fluid film thicknesses on high-speed spinning surfaces inferred while working in cylindrical and spherical coordinate systems can be applied to an arbitrary bell profile. However, the analytical limits of this approximation were not investigated. In all cases, a restriction exists ...


Electrophoresis In Heterogeneous Hydrogels And Applications In Surface Patterning, Ning Ge Jan 2020

Electrophoresis In Heterogeneous Hydrogels And Applications In Surface Patterning, Ning Ge

Theses and Dissertations--Mechanical Engineering

The creation of chemical micropatterns on surfaces makes it possible to add unique chemical functionality to surfaces, modifying properties such as wettability, or even adding the ability to selectively bind other molecules. The creation of biochemical surface patterning in particular is useful in a variety of fields including tissue engineering and highthroughput drug screening. There are many existing surface patterning techniques which focus on precise control over the patterned geometry, even down to submicron scale features, but they do not allow local control over chemical concentration. So the results are high resolution patterns with binary concentration. There are also existing ...


Filtered-Dynamic-Inversion Control For Unknown Minimum-Phase Systems With Unknown Relative Degree, Sumit Suryakant Kamat Jan 2020

Filtered-Dynamic-Inversion Control For Unknown Minimum-Phase Systems With Unknown Relative Degree, Sumit Suryakant Kamat

Theses and Dissertations--Mechanical Engineering

We present filtered-dynamic-inversion (FDI) control for unknown linear time-invariant systems that are multi-input multi-output and minimum phase with unknown-but-bounded relative degree. This FDI controller requires limited model information, specifically, knowledge of an upper bound on the relative degree and knowledge of the first nonzero Markov parameter. The FDI controller is a single-parameter high-parameter-stabilizing controller that is robust to uncertainty in the relative degree. We characterize the stability of the closed-loop system. We present numerical examples, where the FDI controller is implemented in feedback with mathematical and physical systems. The numerical examples demonstrate that the FDI controller for unknown relative degree ...


Influence Of Size Effects On Surface Generation During Finish Machining And Surface Integrity In Ti-6al-4v, Ian S. Brown Jan 2020

Influence Of Size Effects On Surface Generation During Finish Machining And Surface Integrity In Ti-6al-4v, Ian S. Brown

Theses and Dissertations--Mechanical Engineering

Finish machining is an essential manufacturing process that is used to enhance the mechanical characteristics of critical components. The deformation that occurs at the tool and workpiece interface in finish machining significantly affects a host of component properties, commonly referred to as “surface integrity” properties. Surface roughness is a machining deformation-affected characteristic that is of high relevance in contemporary manufacturing. However, over recent decades it has been made clear that the material properties of the deformed surface layers are relevant to component performance as well. Predicting the overall surface quality of a machined component is of great relevance to the ...


Correlating The Physicochemical Properties Of Magnesium Stearate With Tablet Dissolution And Lubrication, Julie L. Calahan Jan 2020

Correlating The Physicochemical Properties Of Magnesium Stearate With Tablet Dissolution And Lubrication, Julie L. Calahan

Theses and Dissertations--Pharmacy

Magnesium stearate (MgSt) is the most commonly used pharmaceutical excipient and is present in over half the tablet formulations on the market. In spite of its popularity as an effective lubricant, it has been repeatedly recognized that there is significant variability between MgSt samples, which can cause inconsistent lubrication between batches of MgSt. The hypothesis of this research is that the batch-to-batch variability in tablet lubrication and dissolution observed in tablet formulations containing different MgSt samples can be correlated with differences in MgSt physicochemical properties (fatty acid salt composition, crystal hydrate form, particle size and surface area). Developing correlations between ...


Optimization Of Induction Quenching Processes For Hss Roll Based On Mmpt Model, Ligang Liu, Hui Yu, Zhiqiang Yang, Chunmei Zhao, Tongguang Zhai Jun 2019

Optimization Of Induction Quenching Processes For Hss Roll Based On Mmpt Model, Ligang Liu, Hui Yu, Zhiqiang Yang, Chunmei Zhao, Tongguang Zhai

Chemical and Materials Engineering Faculty Publications

To improve the comprehensive performance of high speed steel (HSS) cold rolls, the induction hardening processes were analyzed by numerical simulation and experimental research. Firstly, a modified martensitic phase transformation (MMPT) model of the tested steel under stress constraints was established. Then, the MMPT model was fed into DEFORM to simulate the induction quenching processes of working rolls based on an orthogonal test design and the optimal dual frequency of the induction quenching process was obtained. The results indicate that the depth of the roll’s hardened layer increases by 32.5% and the axial residual tensile stress also becomes ...


Transient Analysis Of Diffusion-Induced Deformation In A Viscoelastic Electrode, Yaohong Suo, Fuqian Yang Jun 2019

Transient Analysis Of Diffusion-Induced Deformation In A Viscoelastic Electrode, Yaohong Suo, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

In this study, we analyze the transient diffuse-induced-deformation of an electrode consisting of the conducting polymer polypyrrole (PPY) by using the theories of linear viscoelasticity and diffusion-induced stress. We consider two constitutive relationships with dependence of viscosity on strain rate: Kelvin-Voigt model and three-parameter solid model. A numerical method is used to solve the problem of one-dimensional, transient diffusion-induced-deformation under potentiostatic operation. The numerical results reveal that the maximum displacement occurs at the free surface and the maximum stress occurs at the fixed end. The inertia term causes the stress to increase at the onset of lithiation. The stress decreases ...


Limit Equilibrium Method-Based Shear Strength Prediction For Corroded Reinforced Concrete Beam With Inclined Bars, Yafei Ma, Baoyong Lu, Zhongzhao Guo, Lei Wang, Hailong Chen, Jianren Zhang Mar 2019

Limit Equilibrium Method-Based Shear Strength Prediction For Corroded Reinforced Concrete Beam With Inclined Bars, Yafei Ma, Baoyong Lu, Zhongzhao Guo, Lei Wang, Hailong Chen, Jianren Zhang

Mechanical Engineering Faculty Publications

Shear strength is a widely investigated parameter for reinforced concrete structures. The corrosion of reinforcement results in shear strength reduction. Corrosion has become one of the main deterioration factors in reinforced concrete beam. This paper proposes a shear strength model for beams with inclined bars based on a limit equilibrium method. The proposed model can be applied to both corroded and uncorroded reinforced concrete beams. Besides the tensile strength of longitudinal steel bars, the shear capacity provided by the concrete on the top of the diagonal crack, the tensile force of the shear steel at the diagonal crack, the degradation ...


Fluorescence Of Cdse/Zns Quantum Dots In Toluene: Effect Of Cyclic Temperature, Ting Chen, Weiling Luan, Shaofu Zhang, Fuqian Yang Feb 2019

Fluorescence Of Cdse/Zns Quantum Dots In Toluene: Effect Of Cyclic Temperature, Ting Chen, Weiling Luan, Shaofu Zhang, Fuqian Yang

Chemical and Materials Engineering Faculty Publications

Quantum dots (QDs) are the potential material for the application in optical thermometry, and have been successfully applied to solar cells, LEDs, bio-labeling, structural health monitoring, etc. In this paper, we study the fluorescence properties of CdSe/ZnS QDs in toluene under the action of heating-cooling cycles. The experimental results show that, in a heating-cooling cycle, increasing temperature causes red-shift of the emission peak and the decrease of the PL intensity, and decreasing temperature causes blue-shift of the emission peak and the increase of the PL intensity. The surface structures of the QDs likely are dependent on the cycle numbers ...


Achieving Superelasticity In Additively Manufactured Niti In Compression Without Post-Process Heat Treatment, Narges Shayesteh Moghaddam, Soheil Saedi, Amirhesam Amerinatanzi, Alejandro Hinojos, Ali Ramazani, Julia Kundin, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia Jan 2019

Achieving Superelasticity In Additively Manufactured Niti In Compression Without Post-Process Heat Treatment, Narges Shayesteh Moghaddam, Soheil Saedi, Amirhesam Amerinatanzi, Alejandro Hinojos, Ali Ramazani, Julia Kundin, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia

Mechanical Engineering Faculty Publications

Shape memory alloys (SMAs), such as Nitinol (i.e., NiTi), are of great importance in biomedical and engineering applications due to their unique superelasticity and shape memory properties. In recent years, additive manufacturing (AM) processes have been used to produce complex NiTi components, which provide the ability to tailor microstructure and thus the critical properties of the alloys, such as the superelastic behavior and transformation temperatures (TTs), by selection of processing parameters. In biomedical applications, superelasticity in implants play a critical role since it gives the implants bone-like behavior. In this study, a methodology of improving superelasticity in Ni-rich NiTi ...


Enhanced Surface Integrity With Thermally Stable Residual Stress Fields And Nanostructures In Cryogenic Processing Of Titanium Alloy Ti-6al-4v, James R. Caudill Jan 2019

Enhanced Surface Integrity With Thermally Stable Residual Stress Fields And Nanostructures In Cryogenic Processing Of Titanium Alloy Ti-6al-4v, James R. Caudill

Theses and Dissertations--Mechanical Engineering

Burnishing is a chipless finishing process used to improve surface integrity by severe plastic deformation (SPD) of surface asperities. As surface integrity in large measure defines the functional performance and fatigue life of aerospace alloys, burnishing is thus a means of increasing the fatigue life of critical components, such as turbine and compressor blades in gas turbine engines. Therefore, the primary objective of this dissertation is to characterize the burnishing-induced surface integrity of Ti-6Al-4V alloy in terms of the implemented processing parameters. As the impact of cooling mechanisms on surface integrity from SPD processing is largely unexplored, a particular emphasis ...


Dust Transportation And Settling Within The Mine Ventilation Network, Anand Kumar Jan 2019

Dust Transportation And Settling Within The Mine Ventilation Network, Anand Kumar

Theses and Dissertations--Mining Engineering

Dust is ubiquitous in underground mine activities. Continuous inhalation of dust could lead to irreversible occupational diseases. Dust particles of size lower than 75.0 µm, also known as float coal dust, can trigger a coal dust explosion following a methane ignition. Ventilation air carries the float coal dust from the point of production to some distance before it’s deposited on the surfaces of underground coal mine. Sources of dust are widely studied, but study of dust transportation has been mainly based on experimental data and simplified models. An understanding of dust transportation in the mine airways is ...


An Analysis Of Resistance Spot Weld Quality Based On Acoustic And Electrical Signatures, Ivan Charles Butler Jan 2019

An Analysis Of Resistance Spot Weld Quality Based On Acoustic And Electrical Signatures, Ivan Charles Butler

Theses and Dissertations--Manufacturing Systems Engineering

The union of a set of materials by way of Resistance Spot Welding is designed so that once fused together, a substantial amount of intentional, external force must be applied to separate the contents. Therefore, Resistance Spot Welding is often the preferred fusion method in high-volume manufacturing processes. The result of Resistance Spot Welding however is the formation of a weld nugget which is not visible to the naked eye. Destructive and/or ultrasonic methods applied off-line must be used to determine the quality of each weld; both inefficient and expensive processes. The following research analyzes the data fed back ...


Implementation And Analysis Of True Lean In A Startup Company By Using Pdca Model, A Case Study In A Manufacturing Venture, Ankit Jangid Jan 2019

Implementation And Analysis Of True Lean In A Startup Company By Using Pdca Model, A Case Study In A Manufacturing Venture, Ankit Jangid

Theses and Dissertations--Manufacturing Systems Engineering

The purpose of this research is to implement and analyze the true lean transformation in a manufacturing start-up organization. Often, lean transformations are observed in developed manufacturing organizations having sophisticated production lines and numerous employees, where lean tools are utilized to reduce waste while increasing profit. However, this type of transformation is narrowly focused on quantifiable process results and falls short of the ultimate goal, establishing a true lean culture within the organization. As a result, it is recommended that true lean principles, philosophies, culture, operations environment and tools be applied at the very beginning stages of an organization, or ...


Investigation Of Chip-Form And Tool-Wear In Turning Of Hardened Af9628 Alloy Under Various Cooling And Lubrication Conditions, Jason Wolf Jan 2019

Investigation Of Chip-Form And Tool-Wear In Turning Of Hardened Af9628 Alloy Under Various Cooling And Lubrication Conditions, Jason Wolf

Theses and Dissertations--Manufacturing Systems Engineering

Next generation defense and commercial applications for structural steels require new alloys that eliminate or reduce critical elements from their composition to lower cost and improve manufacturability, while maintaining or exceeding high strength and toughness requirements. A new alloy, denoted as AF9628, has recently been developed for this purpose and its manufacturing characteristics and the material response in component manufacturing must be fully understood.

In the present study, hardened AF9628 alloy was turned with a coated carbide cutting tool under fixed cutting speed, feed rate, and depth of cut parameters. This work focuses on chip-form and tool-wear analysis to understand ...


Design And Process Of 3d-Printed Parts Using Composite Theory, Jordan Garcia Jan 2019

Design And Process Of 3d-Printed Parts Using Composite Theory, Jordan Garcia

Theses and Dissertations--Mechanical Engineering

3D printing is a revolutionary manufacturing method that allows the productions of engineering parts almost directly from modeling software on a computer. With 3D printing technology, future manufacturing could become vastly efficient. However, it is observed that the procedures used in 3D printing differ substantially among the printers and from those used in conventional manufacturing. In this thesis, the mechanical properties of engineering products fabricated by 3D printing were comprehensively evaluated and then compared with those made by conventional manufacturing. Three open-source 3D printers, i.e., the Flash Forge Dreamer, the Tevo Tornado, and the Prusa, were used to fabricate ...


Computationally Efficient, Multi-Domain Hybrid Modeling Of Surface Integrity In Machining And Related Thermomechanical Finishing Processes, Julius M. Schoop, David Adeniji, Ian S. Brown Jan 2019

Computationally Efficient, Multi-Domain Hybrid Modeling Of Surface Integrity In Machining And Related Thermomechanical Finishing Processes, Julius M. Schoop, David Adeniji, Ian S. Brown

Mechanical Engineering Faculty Publications

In order to enable more widespread implementation of sophisticated process modeling, a novel, rapidly deployable multi-physics hybrid model of surface integrity in finishing operations is proposed. Rather than modeling detailed chip formation mechanics, as is common in numerical models, the proposed models integrates existing analytical and semi-empirical models of the plastic, elastic, thermal and thermodynamic domains. Using this approach, highly complex surface integrity phenomena such as residual stresses, grain size, phase composition, microhardness profile, etc. can be accurately predicted in a manner of seconds. It is envisioned that this highly efficient modeling scheme will drive new innovations in surface engineering.


Indoor-Wireless Location Techniques And Algorithms Utilizing Uhf Rfid And Ble Technologies, Ann M. Whitney Jan 2019

Indoor-Wireless Location Techniques And Algorithms Utilizing Uhf Rfid And Ble Technologies, Ann M. Whitney

Theses and Dissertations--Mechanical Engineering

The work presented herein explores the ability of Ultra High Frequency Radio Frequency (UHF RF) devices, specifically (Radio Frequency Identification) RFID passive tags and Bluetooth Low Energy (BLE) to be used as tools to locate items of interest inside a building. Localization Systems based on these technologies are commercially available, but have failed to be widely adopted due to significant drawbacks in the accuracy and reliability of state of the art systems. It is the goal of this work to address that issue by identifying and potentially improving upon localization algorithms.

The work presented here breaks the process of localization ...


Design And Testing Of A Wind Energy Harnessing System For Forced Convective Drying Of Grain In Low Wind Speed, Warm And Humid Climates, Francis Akumabi Agbali Jan 2019

Design And Testing Of A Wind Energy Harnessing System For Forced Convective Drying Of Grain In Low Wind Speed, Warm And Humid Climates, Francis Akumabi Agbali

Theses and Dissertations--Biosystems and Agricultural Engineering

Forced convective drying using a wind turbine mechanically connected to a ventilation fan was hypothesized for low cost and rapid grain drying in developing countries. The idea was tested using an expandable wind turbine blade system with variable pitch, at low wind speeds in a wind tunnel. The design was based on empirical and theoretical models embedded in a graphical user interface (GUI) created to estimate airflow-power requirements for drying ear corn. Output airflow (0.0016 - 0.0052 m3kg-1s-1) increased within the study wind speed range (2.0 - 5.5 m/s). System efficiency peak ...


Quantification Of Myocardial Mechanics In Left Ventricles Under Inotropic Stimulation And In Healthy Right Ventricles Using 3d Dense Cmr, Zhan-Qiu Liu Jan 2019

Quantification Of Myocardial Mechanics In Left Ventricles Under Inotropic Stimulation And In Healthy Right Ventricles Using 3d Dense Cmr, Zhan-Qiu Liu

Theses and Dissertations--Mechanical Engineering

Statistical data from clinical studies indicate that the death rate caused by heart disease has decreased due to an increased use of evidence-based medical therapies. This includes the use of magnetic resonance imaging (MRI), which is one of the most common non-invasive approaches in evidence-based health care research. In the current work, I present 3D Lagrangian strains and torsion in the left ventricle of healthy and isoproterenol-stimulated rats, which were investigated using Displacement ENcoding with Stimulated Echoes (DENSE) cardiac magnetic resonance (CMR) imaging. With the implementation of the 12-segment model, a detailed profile of regional cardiac mechanics was reconstructed for ...


Development Of A Muffler Insertion Loss Flow Rig, Jonathan Chen Jan 2019

Development Of A Muffler Insertion Loss Flow Rig, Jonathan Chen

Theses and Dissertations--Mechanical Engineering

Mufflers and silencers are commonly used to attenuate noise sources such as internal combustion engines and HVAC systems. Typically, these environments contain mean flow that can affect the acoustic properties of the muffler components and may produce flow generated noise. To characterize the muffler performance, common metrics such as insertion and transmission loss and noise reduction are used in industry. Though transmission loss without flow is often measured and is a relatively simple bench top experiment and useful for model validation purposes, mean flow can significantly affect the muffler performance. There are a few existing and commercial transmission loss rigs ...