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Articles 1 - 30 of 34
Full-Text Articles in Engineering Science and Materials
Property Measurements And Evaluation Of Heat Leak, Nathan Race
Property Measurements And Evaluation Of Heat Leak, Nathan Race
All Theses
Heat transport in capillary wick structures is an important parameter in loop heat pipe (LHP) design. The purpose of this study was to investigate the conductive heat leak in operating capillary wick structures. The heat leak is the portion of applied heat load conducted through the wick in spite of the convection of working fluid. Four sintered 316 stainless steel wicks were tested for porosity, effective thermal conductivity, pore size, and heat leak. Pore sizes were found to correlate well with the nominal pore size and pores were very narrowly distributed within a size range of approximately 1-10μm. Effective thermal …
Thermal Diffusion Coefficient Modeling For High Pressure Combustion Simulations, Soundararaghavan Vasudevan
Thermal Diffusion Coefficient Modeling For High Pressure Combustion Simulations, Soundararaghavan Vasudevan
All Theses
The effects of Soret and Dufour diffusion on the behavior of high pressure laminar diffusion flames relevant to modern combustion devices are investigated. A novel model for thermal diffusion coefficients is developed based on experimental data found in the literature and the principle of corresponding states. The new model is first compared with existing models and experimental data and is shown to be more accurate and to exhibit correct behavior in the limit of high temperature relevant to combustion. The model furthermore does not exhibit sensitivity to the equation of state, its mixing rules, or unphysical sign changes observed in …
The Role Of Computer Aided Engineering In Developing A Combined Trash And Recycling Truck : A Case Study, Peter Johnston
The Role Of Computer Aided Engineering In Developing A Combined Trash And Recycling Truck : A Case Study, Peter Johnston
All Theses
This work will illustrate how Environmental America Inc., EAI, and the Clemson University design team utilized lean manufacturing principles to revolutionize the curbside waste collection process. Through the application of lean manufacturing principles the number of non-value added steps was significantly reduced and the information gathered from the lean process tree acted as a framework to develop initial constraints and criteria for the vehicle's development. The design team was asked to construct the fifth iteration of the prototype collection vehicle in an effort to minimize vehicle cost, size and weight. An extensive case study will be presented which illustrates how …
An Investigation Of Cavity Pressure As A Process And Quality Indicator In The Micro-Injection Molding Process, Soon-Chun Kuek
An Investigation Of Cavity Pressure As A Process And Quality Indicator In The Micro-Injection Molding Process, Soon-Chun Kuek
All Theses
Increased demand for micro-scale parts and devices is being met in many cases by micro-injection molding of polymer parts. However, part inspection is difficult due to the micro-scale dimension in the micro-injection molding process. In addition, process control also becomes challenging since the process is susceptible to slight changes in process parameters such as mold temperature, injection velocity, and packing pressure. To address these issues, a suitable process monitoring method such as cavity pressure monitoring can be employed to detect any process deviation that may cause defects in part quality. Cavity pressure has been found to be a reliable process …
Surface Finish Control Of 3d Printed Metal Tooling, Brady Godbey
Surface Finish Control Of 3d Printed Metal Tooling, Brady Godbey
All Theses
Solid freeform fabrication (SFF) technology has shown a great deal of promise for the plastic injection molding industry due to its ability to produce complex geometry tooling relatively quickly. However, one shortcoming of metal-based SFF processes is that they have difficulty producing parts with acceptable surface quality. As such, secondary operations, such as machining, are frequently required thereby increasing fabrication time and cost. In addition, there is variation in the surface quality that is dependent upon the surface orientation during the build process. For example, parts produced using the metal-based 3-D printing process have vertical faces with a typical roughness …
Effects Of Support Grid Vane Angles On Single Phase Heat Transfer Within Rod Bundle Subchannels, Michael Cosby
Effects Of Support Grid Vane Angles On Single Phase Heat Transfer Within Rod Bundle Subchannels, Michael Cosby
All Theses
The main goal of this project is to investigate how changes in support grid mixing vane angles affect the single phase heat transfer coefficient for rod bundle flows. Since other studies have been done on these types of flows, the present study also serves the purpose of further solidifying conclusions made in those works. A split-pair mixing vane support grid without weld nugget cutouts is thought to have optimum flow characteristics at a vane angle of 29 degrees. Results obtained from this work have shown this to be true. Vane angles were modified to angles of 37 ¡, 33¡ and …
A Case Study Investigating Rule Based Design In An Industrial Setting, Siva Chavali
A Case Study Investigating Rule Based Design In An Industrial Setting, Siva Chavali
All Theses
This thesis presents a case study on the implementation of a rule based design (RBD) process for an engineer-to-order (ETO) company. The time taken for programming and challenges associated with this process are documented in order to understand the benefits and limitations of RBD. These times are obtained while developing RBD programs for grid assemblies of bottle packaging machines that are designed and manufactured by Hartness International (HI). In this project, commercially available computer-aided design (CAD) and RBD software are integrated to capture the design and manufacturing knowledge used to automate the grid design process of HI. The stages involved …
A Case Study On The Use Of Design Exemplar As A Search And Retrieval Tool, Narasimha Murty Srirangam
A Case Study On The Use Of Design Exemplar As A Search And Retrieval Tool, Narasimha Murty Srirangam
All Theses
This thesis presents a case study examining the suitability of design exemplar technology as a CAD query tool for an industrial scenario. The search and retrieval of geometrically similar mold inserts to save tooling cost for a tire manufacturing company is taken as the case study. During the implementation of the design exemplar as a CAD search and retrieval tool, several limitations of it are identified, such as the difficulty and tediousness in authoring exemplars for real world problems. To overcome these limitations, a new mathematical-based exemplar approach (mathematical model) is developed for tire mold insert retrieval. This approach calculates …
Least Squares Fitting Of Analytic Primitives On A Gpu, Meghashyam Panyam Mohan Ram
Least Squares Fitting Of Analytic Primitives On A Gpu, Meghashyam Panyam Mohan Ram
All Theses
Metrology systems take coordinate information directly from the surface of a manufactured part and generate millions of (X, Y, Z) data points. The inspection process often involves fitting analytic primitives such as sphere, cone, torus, cylinder and plane to these points which represent an object with the corresponding shape. Typically, a least squares fit of the parameters of the shape to the point set is performed. The least squares fit attempts to minimize the sum of the squares of the distances between the points and the primitive. The objective function however, cannot be solved in the closed form and numerical …
Development Of A Design Enabler Tool For Frame Analysis For A Small Enterprise: A Case Study, Madhusudan Kayyar
Development Of A Design Enabler Tool For Frame Analysis For A Small Enterprise: A Case Study, Madhusudan Kayyar
All Theses
This case study investigates the design process followed by a small to medium scale enterprise (SME) that primarily depends on special expertise in the form of a few key individuals. These individuals design products mainly based on past experience, augmented by trial and error. This is an inefficient, time consuming, and expensive way of designing products and evaluating their performance. This study critiques the different steps in the current design process, identifying areas of potential improvement and enhancement through application of formal design methods and innovative design enablers. The 'Design Enablers' are design tools that assist the designer at various …
Mixed Convective Heat Transfer And Evaporation At The Air-Water Interface, Prasad Gokhale
Mixed Convective Heat Transfer And Evaporation At The Air-Water Interface, Prasad Gokhale
All Theses
Functional forms for mixed convective heat transfer and evaporation from an air-water interface were obtained. To obtain these functions, heat transfer and evaporation rates from the air-water interface of an evaporating body of water were quantified in a wind/water tunnel in the presence of an oleyl alcohol monolayer on the water surface. The Nusselt (Nu) and Sherwood (Sh) numbers, parameterizing the dimensionless heat and mass transfer respectively, for transport from the water bulk to air were expressed as functions of the air side Rayleigh (Ra) and Reynolds (Re) numbers. The Nu and Sh were calculated for a range of Ra …
Morphological Charts: A Systematic Exploration Of Qualitative Design Space, Gregory Smith
Morphological Charts: A Systematic Exploration Of Qualitative Design Space, Gregory Smith
All Theses
A morphological chart is a tool that represents a large qualitative design space. These charts list the functions identified for the design problem, and the means (solutions) that can perform each function. Combining one means for each function will produce a potential integrated conceptual design solution. Repeating this process with every possible combination contained in the morphological chart will generate a long list of conceptual design solutions. Not all of these solutions will be practical, or even physically possible.
As it is difficult to analyze a long list of design solutions and as at present, there are no systematic design …
A Comparative Fault Diagnosis Methodology Based On Time Series Analysis Of System's Signals, Hany Bassily
A Comparative Fault Diagnosis Methodology Based On Time Series Analysis Of System's Signals, Hany Bassily
All Dissertations
The detection of system anomalies represents an important task in safety critical systems. Over the past two decades, advances in data manipulation techniques and sensor technology have contributed to the widespread application of signal processing concepts for fault diagnosis. However, the majority of these signal processing, or data driven, diagnostics do not possess the redundancy level exhibited in conventional model-based methods. Among signal processing methods, time series analysis is advantageous since it offers insight into the underlying dynamics and forecasts system behavior. Furthermore, the data driven method allows the depiction of system dynamics with an increased level of redundancy. This …
A Hydraulic Actuated Thermal Management System For Large Displacement Engine Cooling Systems, Peyton Frick
A Hydraulic Actuated Thermal Management System For Large Displacement Engine Cooling Systems, Peyton Frick
All Theses
The performance of automotive cooling systems can be improved by replacing the traditional mechanically driven radiator fan and water pump assemblies with computer controlled components. The introduction of electric servo-motors to drive the cooling components can improve temperature tracking, which should increase fuel efficiency and decrease tailpipe emissions. However, the power requirement for these electric motors increases with greater cooling demands if the radiator surface area remains constrained. For heavy-duty applications, where engines are subjected to significant cooling loads, electric motors may become impractical due to their increased size and power requirements; in these situations, hydraulic-based components are advantageous due …
Simulation Of A Backrest Moment Test For An Automotive Front Seat Using Nonlinear Contact Finite Element Analysis , Abhinand Chelikani
Simulation Of A Backrest Moment Test For An Automotive Front Seat Using Nonlinear Contact Finite Element Analysis , Abhinand Chelikani
All Theses
Computer aided engineering and finite element simulation are essential in order to predict accurately the safety performance of automotive structures in an event of crash. In this work, finite element simulation is used to evaluate the strength and deflection characteristics of a reference automotive front seat in an event of vehicle rear impact. Understanding the strength-deflection characteristics of front automotive seats during vehicle rear impact is important to ensure the safety function of the seat. The safety function is measured based on a moment test in accordance with government (ECE R17) regulations. Accurate finite element modeling of a reference seat …
Exact Solution Of Time History Response For Dynamic Systems With Coupled Damping Using Complex Mode Superposition, Manoj Kumar Chinnakonda
Exact Solution Of Time History Response For Dynamic Systems With Coupled Damping Using Complex Mode Superposition, Manoj Kumar Chinnakonda
All Theses
An exact solution method for general, non-proportional damping time history response for piece-wise linear loading proposed by Dickens is generalized to piece-wise quadratic loading. Comparisons are made to Trapezoidal and Simpson's quadrature rules for approximating the time integral of the weighted generalized forcing function in the exact solution to the decoupled modal equations arising from state-space modal analysis of linear dynamic systems. The time integral of the forcing function is recognized as a weighted integral with complex exponential and the general update formulas are derived using polynomial interpolation to the forcing function. Closed-form expressions for the weighting parameters in the …
Registration Using Graphics Processor Unit, Koushik Aravalli
Registration Using Graphics Processor Unit, Koushik Aravalli
All Theses
Data point set registration is an important operation in coordinate metrology. Registration is the operation by which sampled point clouds are aligned with a CAD model by a 4X4 homogeneous transformation (e.g., rotation and translation). This alignment permits validation of the produced artifact's geometry. State-of-the-art metrology systems are now capable of generating thousands, if not millions, of data points during an inspection operation, resulting in increased computational power to fully utilize these larger data sets. The registration process is an iterative nonlinear optimization operation having an execution time directly related to the number of points processed and CAD model complexity. …
Nonlinear Modeling Of The Adsorption-Induced Surface Stress In Piezoelectrically-Driven Microcantilever Biosensors, Mana Afshari
Nonlinear Modeling Of The Adsorption-Induced Surface Stress In Piezoelectrically-Driven Microcantilever Biosensors, Mana Afshari
All Theses
Microcantilever-based biosensors are rapidly becoming an enabling sensing technology for a variety of label-free biological applications due to their extreme applicability, versatility and low cost. These sensors operate through the adsorption of species on the functionalized surface of microcantilevers. The adsorption of biological species induces surface stress which originates from the molecular interactions such as adhesion forces of attraction/repulsion, electrostatic forces or the surface charge redistribution of the underlying substrate. This surface stress, consequently, alters the resonance frequency of the microcantilever beam.
This study presents a general framework towards modeling resonance frequency changes induced due to the surface stress arising …
Development Of A Microscopic Moirž Interferometry System, Jeremy Brougher
Development Of A Microscopic Moirž Interferometry System, Jeremy Brougher
All Theses
The human tooth is an amazing structure that is worthy of detailed research and analysis. For over half a century, various tests have been conducted to acquire more information about the structural and material properties of dentin, enamel, and the dentin-enamel junction. Unfortunately, variations still exist in the experimental results, even in the most recently collected data. The primary focus of the majority of material property testing on human teeth has been hardness testing utilizing indentation and nanoindentation analysis. However, several limitations still exist with the indentation technique. Thus, the moirŽ fringe analysis method, specifically microscopic moirŽ interferometry, has been …
Analyzing Relationships Between Lightning And Rain In Order To Improve Estimation Accuracy Of Rain , Justin Lapp
Analyzing Relationships Between Lightning And Rain In Order To Improve Estimation Accuracy Of Rain , Justin Lapp
All Theses
The remote estimation of rainfall rate R is essential for the aviation industry, agriculture, and food warning. Radar, the current means of R estimation, is not available in much of the world. In addition, this measurement involves a level of inaccuracy. Using lightning to detect rain is a relatively inexpensive alternative to radar systems and can be done from existing satellites. Previous research has revealed correlations between lightning and rain, suggesting either that it is possible to estimate R using lightning, or that it is possible to use it to correct for a portion of the radar inaccuracies. These correlations …
Advanced Thermal Management For Internal Combustion Engines, Thomas Mitchell
Advanced Thermal Management For Internal Combustion Engines, Thomas Mitchell
All Theses
The automotive cooling system has unrealized potential to improve internal combustion engine performance through enhanced coolant temperature control and reduced parasitic losses. Advanced automotive thermal management systems use controllable actuators (e.g., smart thermostat valve, variable speed water pump, and electric radiator fan) in place of conventional mechanical cooling system components to improve engine temperature tracking over most operating ranges. To optimize advanced cooling system performance, the electro-mechanical actuators must work in harmony to control engine temperature. The design and placement of cooling components should also be considered when attempting to maximize the performance.
In this research project, two distinct vehicle …
Measurement And Analysis Of Hydromechanical Effects In Fractured Rock, Todd Schweisinger
Measurement And Analysis Of Hydromechanical Effects In Fractured Rock, Todd Schweisinger
All Dissertations
Fractures in rock hold important stores of water and petroleum, and slight changes in fracture aperture accompanying drawdown from pumping wells play a key role in recovering these resources. Four accomplishments are described that advance insight into the behavior and characterization of fractured crystalline rock.
First was the development of two removable borehole extensometers that enable small axial displacements to be measured during hydraulic well tests. The extensometers consist of four major components: 1.) a pair of anchors; 2.) a displacement transducer 3.) a registration system, and; 4.) a temperature-compensated reference rod. One extensometer uses an axial reference rod with …
Nonlinear Vibration And Frequency Response Analysis Of Nanomechanical Cantilever Beams, Seyed Nima Mahmoodi
Nonlinear Vibration And Frequency Response Analysis Of Nanomechanical Cantilever Beams, Seyed Nima Mahmoodi
All Dissertations
Microcantilevers are one the most commonly utilized microelectromechanical systems in a variant of the ultra-precise scanning and characterization application. Of particular interest, the problem of vibrations of microcantilevers has recently received considerable attention due to its application in several nanotechnological instruments such as atomic force microscopy, nanomechanical cantilever sensors and friction force microscopy. For applications such as these, the problem of coupled flexural-torsional nonlinear vibrations of a piezoelectrically-actuated microcantilever beam is considered in this dissertation. The actuation and sensing are both facilitated through bonding a piezoelectric layer (here, ZnO) on the microcantilever surface. The beam is considered to have simultaneous …
Design And Development Of An In-House Scanning Tunneling Microscope System, Esvar Subramanian
Design And Development Of An In-House Scanning Tunneling Microscope System, Esvar Subramanian
All Theses
ABSTRACT
The invention of Scanning Tunneling Microscope (STM) by Binnig and Rohrer in 1982 eliminated the use of optical lenses and replaced the conventional optical microscopes with a new class of microscopes called the Scanning Probe Microscopes (SPM). Because of their unique characteristics such as higher resolution and acquisition of nano level images without affecting the physical properties of the sample, they have found wide applications in a variety of scientific disciplines such as biology, material science and electrochemistry. After considerable advancements in instrumentation, the STM has evolved as a nanomanipulation and nanofabrication tool. It operates in two modes: constant …
Optimal Placement Of Metal Foils In Ultrasonic Consolidation Process, Raji Rexavier
Optimal Placement Of Metal Foils In Ultrasonic Consolidation Process, Raji Rexavier
All Theses
Ultrasonic Consolidation is a combination of additive and subtractive
manufacturing processes resulting in considerable material waste. This waste is a
function of the geometry of the part being manufactured and of the relative
placement of the layer with respect to the metal bands. Thus the waste may be
minimized by careful choice of the layer angle and offset from the original
position.
Previous work done in this field had developed an automated algorithm which
optimally places and orients the individual slices of the STL file of the artifact
being manufactured. However, the problem was solved on a 2-D scale and …
Real Time Prognostic Strategies Application To Gas Turbines, Rajat Sekhon
Real Time Prognostic Strategies Application To Gas Turbines, Rajat Sekhon
All Theses
Gas turbines are increasingly deployed throughout the world to provide electrical and mechanical power in consumer and industrial sectors. The efficiency of these complex multi-domain systems is dependant on the turbine's design, established operating envelope, environmental conditions, and maintenance schedule. A real-time health management strategy can enhance overall plant reliability through the continual monitoring of transient and steady-state system operations. The availability of sensory information for control system needs often allow diagnostic/prognostic algorithms to be executed in a parallel fashion which warn of impending system degradations. Specifically, prognostic strategies estimate the future plant behavior which leads to minimized maintenance costs …
Modeling Requirements Propagation To Generate Solutions For Minimizing Mass, Thulasiram Ezhilan
Modeling Requirements Propagation To Generate Solutions For Minimizing Mass, Thulasiram Ezhilan
All Theses
This thesis investigates the issue of weight reduction in moderately complex systems by addressing how to cascade the requirements to the individual components. Though mass can be reduced using different techniques such as material substitution or structural optimization; a systematic method for allocating mass as a function of requirements is necessary to provide novel alternate solutions that enable reduction of mass of the system while satisfying the requirements and tests governing them. Such a method can be developed by exploring different aspects of achieving weight reduction through change propagation in the parameters/elements governing the system. Though efforts have been made …
Temperature Control Of An Air Shower, Vedik Bobba
Temperature Control Of An Air Shower, Vedik Bobba
All Theses
Accuracy and repeatability in measurement is a primary concern in improving and maintaining the quality of a product in an industry. In the case of coordinate measuring machines, these factors are affected due to the ambient conditions. Specifically, change in temperature affects machine geometry and causes positioning errors. As a result, temperature and humidity control inside the housing has become an important and integrated concern of measuring machine. This research concentrates on the modeling, design, control and validation of an air shower to meet a 20 ± 0.1 ¼C specification.
The optimum performance of the control of temperature of air …
Analysis Of Ride Quality Of Tractor Semi-Trailers, Christopher Spivey
Analysis Of Ride Quality Of Tractor Semi-Trailers, Christopher Spivey
All Theses
This thesis develops parameter variation techniques for calculating the set of vehicle parameters that result in the best ride comfort for the driver. The model is a fifteen degree-of-freedom (15 DOF) tractor semi-trailer vertical dynamic ride model. The modeling and simulation techniques used in this thesis are extensions of the research performed by Trangsrud and Vaduri. Features of the model include suspension characteristics for (a) each of the five axles (tractor steer axle, two tractor drive axles, and two trailer axles), (b) tires, (c) a flexible engine mount, (d) the tractor cab, (e) the driver's seat, and (f) a fifth …
Design Of A Controller For A Precision Positioning Machine, Joshua Tarbutton
Design Of A Controller For A Precision Positioning Machine, Joshua Tarbutton
All Theses
System identification was used to build an accurate model of a high-precision measurement system. The model built by system identification was compared to modeling by first laws and showed extremely similar results. Pole-placement control design based on the identified system was used to place the systems' dominant poles. The necessary gains to achieve the desired system response were determined by using the identified model and knowledge of the controller structure. The performance of the model-based controller was compared to actual data of the system and showed that control based on the identified model can be used to accurately control the …