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2022

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Articles 1591 - 1620 of 1663

Full-Text Articles in Mechanical Engineering

การปรับปรุงค่าความผิดพลาดจากการระบุตำแหน่งของวัตถุบนระนาบ 2 มิติ สำหรับระบบสัญญาณไร้สายที่ใช้เซนเซอร์คลื่นความถี่แถบกว้าง, พรพัฒน์ ชีวสุนทร Jan 2022

การปรับปรุงค่าความผิดพลาดจากการระบุตำแหน่งของวัตถุบนระนาบ 2 มิติ สำหรับระบบสัญญาณไร้สายที่ใช้เซนเซอร์คลื่นความถี่แถบกว้าง, พรพัฒน์ ชีวสุนทร

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในปัจจุบันการระบุตำแหน่งภายในอาคารถูกนำมาใช้กันอย่างแพร่หลายในวงกว้าง ในงานวิจัยนี้นำเสนอถึงการปรับปรุงค่าความผิดพลาดของการระบุตำแหน่งในอาคารด้วยเซนเซอร์ที่ใช้คลื่นความถี่แถบกว้าง เซนเซอร์จะถูกติดตั้งอยู่ประจำจุดต่าง ๆ ในพื้นที่ทดลองและจะส่งสัญญาณไปหาเซนเซอร์ตัวที่ต้องการที่จะระบุตำแหน่งที่เคลื่อนที่ไปรอบ ๆ โดยใช้การสื่อสารแบบสองทางระหว่างเซนเซอร์เพื่อให้ได้ระยะห่างระหว่างเซนเซอร์ ค่าที่วัดได้จากเซนเซอร์นั้นมีค่าความผิดพลาดอยู่ร่วม 1 เมตร เพื่อที่จะลดค่าความผิดพลาดและเพิ่มความแม่นยำในการระบุตำแหน่งจึงได้มีการใช้การวิเคราะห์การถดถอยมาเพื่อหาสมการที่เข้ากับรูปแบบความผิดพลาดที่เกิดขึ้นจากเซนเซอร์ และใช้ตัวกรองคาลมานในการลดค่าความผิดพลาดแบบออนไลน์ ผลลัพธ์ที่ได้นั้นสามารถลดความผิดพลาดลงไปได้เหลือ 5 เซ็นติเมตร


Industry 4.0 Remanufacturing: A Novel Approach Towards Smart Remanufacturing, Prashansa Ragampeta Jan 2022

Industry 4.0 Remanufacturing: A Novel Approach Towards Smart Remanufacturing, Prashansa Ragampeta

Masters Theses

“Smart remanufacturing has become more popular in recent years as a result of its multiple benefits and the growing need for society to encourage a circular economy that leads to sustainability. One of the most common end-of-life (EoL) choices that can lead to a circular economy is remanufacturing. As a result, at the end-of-life stage of a product, it is critical to prioritize this choice over other accessible options because it is the only recovery option that retains the same quality as a new product. This work focuses on the numerous technologies that can aid in the improvement of smart …


Stress Analysis On Walls In Complex Fluids With Fluid-Solid Interaction, Dehong Fang Jan 2022

Stress Analysis On Walls In Complex Fluids With Fluid-Solid Interaction, Dehong Fang

Graduate Research Theses & Dissertations

The wall shear stress (WSS) in blood vessels influences many biological processes, such as atherosclerosis, clot growth, angiogenesis, aneurysm rupture, and blood cell transport and adhesion. The deformable red blood cells (RBCs) in blood flow make the WSS even more complex. To analyze the WSS in complex fluids with cell suspensions, numerical simulations of blood flows in simple straight channels were conducted, where the fluid-solid interactions were simulated by immersed boundary-lattice Boltzmann method. The spatiotemporal dynamics of WSS were analyzed using dynamic mode decomposition (DMD), which is a technique that can extract the low-rank spatiotemporal features from complex fluids. The …


A New Boundary Interlock Geometry Design Method For Fdm Multi-Material Part Strengthening, Shivaram Sree Venkata Shanmukha Kakaraparthi Jan 2022

A New Boundary Interlock Geometry Design Method For Fdm Multi-Material Part Strengthening, Shivaram Sree Venkata Shanmukha Kakaraparthi

Graduate Research Theses & Dissertations

Multi-material Fused Deposition Modelling (FDM) enables the cost-effective realization of designs in complex geometries built with multiple materials. However, achieving an adequate level of bonding strength between different materials remains a significant challenge. Besides the traditional way of addressing this challenge by strengthening material bonding at the molecular scale by optimizing the printing parameters, introducing a new design methodology that creates stronger multi-material interface geometry could also offer effective solutions. This work studied the mechanical properties of multi-material printed objects, with a particular focus on the interface zone formed between different materials at their geometrical boundaries. A new mathematical simulation …


A Parametric Study Of Thermochemical Energy Storage Using Chemical Looping For Concentrated Solar Power (Csp) Plants, Imran Anees Mohammed Jan 2022

A Parametric Study Of Thermochemical Energy Storage Using Chemical Looping For Concentrated Solar Power (Csp) Plants, Imran Anees Mohammed

Graduate Research Theses & Dissertations

The use of conventional fossil fuels to generate power has caused great harm to the environment. These fossil fuels, when burnt, release copious amounts of CO_2, causing global warming. Therefore, it is imperative that current energy sources are substituted with renewable energy sources. However, the critical obstacle with renewable energy sources is their intermittency. Solar energy is being captured through photovoltaic plants and concentrated solar power plants. Photovoltaic plants use batteries, which makes the storage of energy limited. Furthermore, an alternative downside is that the constant use of many batteries will considerably increaseincrease the project’s cost. Concentrated solar power plants …


Warm Unit Stand Analysis For Proton Improvement Project Ii, Michael William Pavlick Jan 2022

Warm Unit Stand Analysis For Proton Improvement Project Ii, Michael William Pavlick

Graduate Research Theses & Dissertations

The Proton Improvement Project II, commonly referred to as PIP II, is a linear accelerator overhaul at Fermilab to eventually double the output of its existing proton beam to continue to be the leading force in high energy physics. The proton beam is created through a series of high frequency cryomodules that must be connected utilizing a combination of magnets and vacuum pumps to ensure the beam is properly aligned. A housing mechanism for the magnets and vacuum pumps (Warm Units) will be placed between the cryomodules for realignment and require multiple stages of 6 degree-of-freedom adjustment options, to ensure …


Design And Fabrication Of A Small-Sized Omni-Directional Spherical Robot, Aayush P. Patel Jan 2022

Design And Fabrication Of A Small-Sized Omni-Directional Spherical Robot, Aayush P. Patel

Graduate Research Theses & Dissertations

As we have witnessed through an unprecedented pandemic crisis, a lack of or decreased level of social interactions could have a negative impact on people's mental health. Ample evidence indicates that similar phenomena take place in rodents as socially isolated rodents display a high level of stress and cognitive declination. While spherical robots have recently drawn significant interest in many areas such as education, entertainment, and surveillance due to their ability to move instantaneously in any direction, the objective of this thesis is to design and fabricate a small-sized, self-locomotive omnidirectional robot to provide those animals with physical interactions as …


Development Of Phase Change Thermal Storage Medium: Cooking With More Power And Versatility, Martin Osei Jan 2022

Development Of Phase Change Thermal Storage Medium: Cooking With More Power And Versatility, Martin Osei

Masters Theses

With an Insulated Solar Electric Cooker (ISEC), a 100 W solar panel directly cooks food while providing 5W off-grid electricity access; but it cooks slowly. Storing the day’s energy with phase change thermal storage allows ISEC to cook more rapidly as well as cook after sunset. The ISEC is made by sticking a 3ohm resistive to an aluminum pot (inner phase change assembly PCA) where another cooking pot fits. The resistive heater is surrounded by a bigger pot (outer PCA) that contains the PCM and is tightly sealed. The solar panel is connected to the resistive heater with a thermal …


Temperature Analysis Of A Square Lid-Driven Cavity With Particle Suspensions, Justin Kortge Jan 2022

Temperature Analysis Of A Square Lid-Driven Cavity With Particle Suspensions, Justin Kortge

Graduate Research Theses & Dissertations

Computational fluid dynamics (CFD) and discrete element method (DEM) are powerful tools for simulating systems that contain fluids and particles. Studies of particle fluid systems greatly vary in their applications and complexity, and yet there is a scarcity of studies focused on the thermal characteristics of the fluid. A computational analysis is conducted on two-dimensional flow in a square thermal lid-driven cavity to assess the effect of particle suspensions on the thermal characteristics of the cavity. Most studies analyzing the effect of suspensions in a thermal lid-driven cavity treat the medium as a single homogeneous nanofluid. Those that do treat …


Study Protocol To Analyze The Effects Of Posture And Exoskeleton On Human Exposure To Hand-Transmitted Vibration, Parisa Torkinejad Ziarati Jan 2022

Study Protocol To Analyze The Effects Of Posture And Exoskeleton On Human Exposure To Hand-Transmitted Vibration, Parisa Torkinejad Ziarati

Graduate Research Theses & Dissertations

Exposure to power hand tool-generated vibrations may lead to several health disorders collectively known as hand-arm vibration (HAV) syndromes. Power hand tools are often used in overhead postures in the manufacturing and construction industries. However, HAV risks are examined in the front-of-body posture in the existing safety standards and guidelines. Therefore, it is important to understand the effects of overhead working posture on vibration transmissibility (VT) in the upper extremities (UEs) and the spine. Secondly, there is a rising trend of using occupational exoskeletons (Exos) in the manufacturing and construction industries, especially involving overhead work with power hand tools. However, …


Process Optimization For An Integrated Reverse Osmosis—Pressure Retarded Osmosis Pilot-Scale System Operated On Humboldt Bay, Ca, Galen O'Toole Jan 2022

Process Optimization For An Integrated Reverse Osmosis—Pressure Retarded Osmosis Pilot-Scale System Operated On Humboldt Bay, Ca, Galen O'Toole

Cal Poly Humboldt theses and projects

Pressure retarded osmosis (PRO) is an emerging osmotic power technology that could mitigate the major challenges faced by seawater reverse osmosis desalination (RO): brine disposal and high energy consumption. The primary focus of this paper is process optimization for a linked seawater reverse osmosis (RO) and pressure retarded osmosis (PRO) water purification system. PRO generates power by using osmosis to “pump” water through a membrane from low pressure and low concentration to high pressure and high concentration (RO brine). This commercial-scale pilot effort explores process optimization for pressure retarded osmosis as an industrial process rather than theoretical or experimental process. …


Branched Chain Amino Acid Strain State Monitoring With Raman Spectroscopy And Plasmonic Bowtie Nanoantenna Devices For Early Disease Detection, Caroline A. Campbell Jan 2022

Branched Chain Amino Acid Strain State Monitoring With Raman Spectroscopy And Plasmonic Bowtie Nanoantenna Devices For Early Disease Detection, Caroline A. Campbell

Theses and Dissertations

This work centers on the development and the down-selection of nano-manufactured devices to be used in conjunction with Raman spectroscopy for probing a branched chain amino acid. The nano-manufactured devices integrate plasmonic nanoantennas for the purpose of amplifying molecular fingerprints, which are otherwise difficult to detect, through Surface Enhanced Raman Spectroscopy (SERS). Plasmonic nanostructures can be utilized for a variety of biomedical and biochemical applications to detect the characteristic fingerprint provided by Raman Spectroscopy. The nano-manufactured devices create an electric field that amplifies minute perturbations and raises the signal above background noise. This may provide a deeper understanding of signal …


Development And Optimization Of A Low Volume Air-Jet Dry Powder Inhaler (Dpi) Platform For The Delivery Of High Dose Aerosolized Powder To Infants, Connor Howe Jan 2022

Development And Optimization Of A Low Volume Air-Jet Dry Powder Inhaler (Dpi) Platform For The Delivery Of High Dose Aerosolized Powder To Infants, Connor Howe

Theses and Dissertations

The goal of this research project was to develop an infant air-jet dry powder inhaler (DPI) platform for high-efficiency nose-to-lung (N2L) aerosol administration to infants through optimization of individual system components followed by expansion of the system to higher doses and different formulations using a new approach. Primary challenges associated with aerosol delivery to infants using the N2L route include the extremely narrow extrathoracic airways, short inspiratory times (~0.2 sec), low safe airway pressure (H2O), and very low volumes of air (~10 mL) available to form the aerosol. The infant air-jet DPI system was comprised of three main …


Workforce Development Strategies In Additive Manufacturing, Mel Cossette, Ismail Fidan, Gaffar Gailani, Angran Xiao Jan 2022

Workforce Development Strategies In Additive Manufacturing, Mel Cossette, Ismail Fidan, Gaffar Gailani, Angran Xiao

Publications and Research

Additive Manufacturing (AM), also known as 3D Printing (3DP), is one of the newest manufacturing technologies with growing utilization in our daily life. Parallel to this growth, new materials, machines, and specific processes are being developed to produce parts in better-finished quality, at lower cost, and with shorter production time. However, workforce education in this evolving field has not advanced at the same pace as the technology, lacking proven curriculums, high-quality/accredited degree programs, and specialized advanced degrees. In this paper, some best practices established by the authors are introduced. The list is far from exhaustive but is proven to be …


Cool Thermal Energy Storage: Water And Ice To Alternative Phase Change Materials, Sandra K. S. Boetcher Jan 2022

Cool Thermal Energy Storage: Water And Ice To Alternative Phase Change Materials, Sandra K. S. Boetcher

Publications

Cool thermal energy storage has a long history dating back to ancient times with modern developments beginning in the mid-nineteenth century where blocks of ice were cut from frozen lakes for cooling applications. Today, the prevalent mode of thermal energy storage is the utilization of ice tanks in commercial buildings for peak shaving and load shifting. In this chapter, a summary of different types of water/ice thermal energy storage systems is provided; an overview of alternative phase change materials for use in cool thermal energy storage is given; and alternative phase change material thermal energy systems, their implementation, challenges, and …


A General Coupling Methodology For Unsteady Aerostructural Optimization With Analytic Derivatives, Taylor Mcdonnell, Adam Cardoza, Denis-Gabriel Caprace, Andrew Ning Jan 2022

A General Coupling Methodology For Unsteady Aerostructural Optimization With Analytic Derivatives, Taylor Mcdonnell, Adam Cardoza, Denis-Gabriel Caprace, Andrew Ning

Faculty Publications

Multidisciplinary design optimization offers a comprehensive approach for designing complex aerostructural systems such as wind turbines. Gradient-based multidisciplinary design optimization can be used to optimize complex systems using large numbers of design variables. However, the convergence of gradient-based optimization methods to an optimal solution is highly dependent on the accuracy of the provided derivatives. In this paper, we propose a general method for creating unsteady coupled systems for steady-state, eigenvalue, and time-domain analyses. We then describe how highly accurate derivatives may be obtained from these analyses using a combination of automatic differentiation and analytic methods (including the unsteady adjoint). Finally, …


In-Flow Dynamics Of An Area-Difference-Energy Spring-Particle Red Blood Cell Model On Non-Uniform Grids, Brendan Walsh, Fergal Boyle Jan 2022

In-Flow Dynamics Of An Area-Difference-Energy Spring-Particle Red Blood Cell Model On Non-Uniform Grids, Brendan Walsh, Fergal Boyle

Articles

In this paper the area-difference-energy spring-particle (ADE-SP) red blood cell (RBC) structural model developed by Chen and Boyle is coupled with a lattice Boltzmann flux solver to simulate RBC dynamics. The novel ADE-SP model accounts for bending resistance due to the membrane area difference of RBCs while the lattice Boltzmann flux solver offers reduced computational runtimes through GPU parallelisation and enabling the employment of non-uniform meshes. This coupled model is used to simulate RBC dynamics and predictions are compared with existing experimental measurements. The simulations successfully predict tumbling, tank-treading, swinging and intermittent behaviour of an RBC in shear flow, and …


Tidal Current Turbine Blade Optimisation With Improved Blade Element Momentum Theory And A Non-Dominated Sorting Genetic Algorithm, Eng Jet Yeo, David Kennedy, Fergal O'Rourke Jan 2022

Tidal Current Turbine Blade Optimisation With Improved Blade Element Momentum Theory And A Non-Dominated Sorting Genetic Algorithm, Eng Jet Yeo, David Kennedy, Fergal O'Rourke

Articles

Tidal current energy has the advantage of predictability over most of the other renewable energy resources. However, due to the harsh operating environment and complicated site conditions, developments in this domain have been gradual. Paramount to these points is device design and optimisation of hydrodynamic performance. Recent developments in the correction models of BEM theory have further improved the accuracy of the prediction model. Using an improved blade element momentum theory model that is capable of accurately capturing the downwash angle and combining it with a well-developed and reliable non-dominated sorting genetic algorithm model, an effective and efficient tidal current …


Building Performance - Societal Drive, Programme And Symposium, Joseph Little, Patrick Daly Jan 2022

Building Performance - Societal Drive, Programme And Symposium, Joseph Little, Patrick Daly

Articles

Society is increasingly looking at the construction industry to mitigate the environmental crisis and solve the housing crisis through wholesale embrace of three broad sets of challenges. The MSc in Building Performance (Energy Efficiency in Design) (MSc BP(EED)) was created in 2017 to provide significant upskilling in the knowledge, skills, and software applications of building design professionals so that they can meet these challenges, while creating compliant, sustainable, super-low energy, new and renovated buildings. The delivery of the programme supports upskilling of employed building design professionals at Masters level, encouraging a minority to develop their capacity and interest in research …


Determining Cause Of Failure For Load Cells Supporting Vertical Pressure Vessels Subject To Wind Loading, Seth Nowak Jan 2022

Determining Cause Of Failure For Load Cells Supporting Vertical Pressure Vessels Subject To Wind Loading, Seth Nowak

College of Graduate Studies: Theses & Dissertations

Wind loads cannot be avoided during a natural disaster such as a hurricane and could affect the strength and stability of vertical pressure vessels during exposure. Vertical pressure vessels cater to large wind loads; therefore, it is imperative to study the effect of additional loading on the structures. In this study, three pressure vessels with volumes of 50 CuFt, 200 CuFt, and 1100 CuFt, supported by three equidistant load cells under their legs are individually analyzed to determine von mises stress to estimate yield failure criteria. Two load rating criteria, maximum load capacity and water-filled condition (critical condition) are utilized …


Plasma Spheroidization Of Gas-Atomized 304l Stainless Steel Powder For Laser Powder Bed Fusion Process, M. Hossein Sehhat, Austin T. Sutton, Chia-Hung Hung, Ben Brown, Ronald J. O'Malley, Jonghyun Park, Ming-Chuan Leu Jan 2022

Plasma Spheroidization Of Gas-Atomized 304l Stainless Steel Powder For Laser Powder Bed Fusion Process, M. Hossein Sehhat, Austin T. Sutton, Chia-Hung Hung, Ben Brown, Ronald J. O'Malley, Jonghyun Park, Ming-Chuan Leu

PSMRC Faculty Research

Particles of AISI 304L stainless steel powder were spheroidized by the induction plasma spheroidization process (TekSphero-15 spheroidization system) to assess the effects of the spheroidization process on powder and part properties. The morphology of both as-received and spheroidized powders was characterized by measuring particle size and shape distribution. The chemistry of powders was studied using inductively coupled plasma optical emission spectroscopy for evaluation of composing elements, and the powder’s microstructure was assessed by X-ray diffraction for phase identification and by electron backscattered diffraction patterns for crystallography characterization. The Revolution Powder Analyzer was used to quantify powder flowability. The mechanical properties …


Coastal Wave Powered Reverse Osmosis System, Alexander Raymond Charest, Joeseph Daniel Camobreco, Tori Sweet, Sam Williams, Andrew Lepage, Devan Sack, Meagan Wiggin, Chelsea Kimball, Brendan Reagan Jan 2022

Coastal Wave Powered Reverse Osmosis System, Alexander Raymond Charest, Joeseph Daniel Camobreco, Tori Sweet, Sam Williams, Andrew Lepage, Devan Sack, Meagan Wiggin, Chelsea Kimball, Brendan Reagan

Honors Theses and Capstones

Part of the Marine Energy Collegiate Competition (MECC) is the optional Build and Test Challenge where teams are encouraged to build a portion of their proposed solution. After the conducted testing the laboratory results are compared to the simulated and calculated models. For the MECC the University of New Hampshire (UNH) team decided to use a wave energy converter to produce pressurized water. The pressurized water would be filtered through a reverse osmosis membrane to make it potable. Our system uses the power of the ocean waves to move a float up and down in heave motion. This motion drives …


Am Surface Roughness And Its Impact On Drag, Jackson Landry Chandler Jan 2022

Am Surface Roughness And Its Impact On Drag, Jackson Landry Chandler

Honors Academy

“The main goal of this thesis is to quantify additive manufacturing (AM) surface roughness, as a precursor to identifying its impact on unsteady transient flow properties. Experimental data using the Hirox optical microscopes and SEM imaging collected from the nylon and stainless-steel lattice structures contained an inherent level of surface roughness at the finer scale. Surface Roughness have a negative effect on additively manufactured materials and as such should be mitigated whenever possible. Surface roughness increases unwanted features such as the level of drag, skin friction, negative heat transfer/mass transfer properties, and other unwanted unsteady transitional flow characteristics. Though exceptions …


Fuel Cell Having Corrugated Membrane Electrode Assembly, Jonghyun Park Jan 2022

Fuel Cell Having Corrugated Membrane Electrode Assembly, Jonghyun Park

Patents

An electrochemical reaction cell comprising an anode electrode, a cathode electrode, and a membrane electrode assembly (MEA). The MEA is positioned between the anode electrode and the cathode electrode. The anode electrode, the cathode electrode, and the MEA each have a corrugated shape and are contained within a recess of a housing.


Distributed Process State And Input Estimation For Heterogeneous Active/Passive Sensor Networks, Dzung Minh Duc Tran, Tansel Yucelen, Selahattin Burak Sarsilmaz Jan 2022

Distributed Process State And Input Estimation For Heterogeneous Active/Passive Sensor Networks, Dzung Minh Duc Tran, Tansel Yucelen, Selahattin Burak Sarsilmaz

Patents

Systems and methods are described for estimating a state of a process and an input to the process using a sensor network. Each sensor node in the sensor network is directly to one or more adjacent sensor nodes and indirectly coupled to the remaining sensor nodes through the one or more adjacent sensor nodes. Each sensor node iteratively calculates a new estimated state based on estimations of the state and the input to the process calculated by the sensor node in a previous iteration. The new estimated state is then adjusted based on a difference between a predicted and actual …


A Study Of Reduced Activation Ferritic Martensitic Metal Core Wire For Wire Arc Additive Manufacturing, Alexander L. Reichenbach Jan 2022

A Study Of Reduced Activation Ferritic Martensitic Metal Core Wire For Wire Arc Additive Manufacturing, Alexander L. Reichenbach

College of Graduate Studies: Theses & Dissertations

This study seeks to determine the technical feasibility of fabricating reduced activation ferritic martensitic (RAFM) steel parts, using a wire arc additive manufacturing (WAAM) process. The WAAM process, manufactures a part by depositing layers of metal onto a substrate to build a large scale near net shape part. RAFM alloy steels are next generation steels designed to resist radiation effects in the radiation intense working environments, such as nuclear reactors. To achieve this, process development and testing to design the WAAM production process with the custom RAFM filler wire was carried out. Several welding waveform modes were tested, and it …


Effects Of Titanium And Cerium Addition On Grain Size And Mechanical Properties Of Ductile Iron Castings, Shelton F. Fowler Iv Jan 2022

Effects Of Titanium And Cerium Addition On Grain Size And Mechanical Properties Of Ductile Iron Castings, Shelton F. Fowler Iv

College of Graduate Studies: Theses & Dissertations

According to the Hall-Petch equation, the refinement of grains in metals increases the yield strength of the material. Austenite grain size influences the fineness of microstructural constituents in the ferrous alloys. It is well studied that cerium and titanium refine the austenite in steels and some gray irons, but no studies have been done to systematically explore the effects of cerium and titanium additions on austenite in ductile iron. This study sought to determine the effects of selected levels of these elements on the grain size within ductile iron. A hypoeutectic iron was chosen for testing as the proeutectic phase …


Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan Jan 2022

Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan

College of Graduate Studies: Theses & Dissertations

In recent years the development of rocket engines has been mainly focused on improving the engine cycle and creating new fuels. Rocket nozzle design has not been changed since the late 1960s. Recent needs for reliable and reusable rockets, as well as advancements in additive manufacturing, have brought new interest into the aerospike nozzle concept. This nozzle is a type of altitude adjusting nozzle that is up to 90% more efficient than bell nozzles at low altitudes and spends up to 30% less fuel. Since the nozzle body is submerged in the hot exhaust gasses it is difficult to keep …


Design Of Human Inspired Feet For Mithra, A High-Performance Humanoid Robot, Spencer Lyle Brewster Jan 2022

Design Of Human Inspired Feet For Mithra, A High-Performance Humanoid Robot, Spencer Lyle Brewster

Electronic Theses and Dissertations

This thesis explores the foot design for the new humanoid robot Mithra, with the goal to improve impact mitigation, natural gait throughout the gait cycle and balance. Using human gait parameters, a stiff aluminum foot was designed to emulate human center of pressure rollover trajectories. In addition, a 2D dynamic Finite Element Analysis (FEA) of the gait cycle was created in Abaqus to rapidly prototype foot designs. Data from the FE model provided impact forces, parameters for distal foot power evaluation and maximum lean angles. From this model a flexible nylon foot was optimized for the given design objectives. The …


Contact Simulation For Evaluating Patient Specific Surgical Guide Stability, Vincent Nierste Jan 2022

Contact Simulation For Evaluating Patient Specific Surgical Guide Stability, Vincent Nierste

Electronic Theses and Dissertations

This study proposes a novel computational method to quantify guide stability for Patient Specific Instrumentation (PSI) guides. A finite element contact model was used to analyze the final position of PSI guides on a femur across a range of loading parameters representing forces applied by a surgeon during operative use. Separate segmentation methods were used for the guide and bone geometry to represent differences between segmentation and actual patient geometry. The region of loading parameters over which the guide exhibited a consistent final position was measured and reported as Guide Stability Score. The model was verified using cadaver specimens for …