Mechanical Engineering Commons^™

Measurement Of Refractive Index Change Of Optical Fiber Core Induced By Femtosecond Laser Scanning, Y. Han, T. Wei, Hai-Lung Tsai, Hai Xiao

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We report a new method to measure the refractive index change in optical fiber core induced by femtosecond (fs) laser exposure. An in-line Fabry-Perot interferometer, serving as the measurement platform, is constructed on a commercial single-mode optical fiber by onestep femtosecond (fs) laser fabrication. A positive refractive index change is observed and measured accurately as the laser pulse energy surpasses the ablation threshold.

Steady-State Green’S Function Solution For Moving Media With Axial Conduction, A. Haji-Sheikh, J. V. Beck, Kevin D. Cole

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this presentation is the development of a generalized steady-state Green’s function solution to study the temperature field in moving bodies. This type of solution permits the inclusion of different nonhomogeneous boundary conditions, volumetric heat sources, and possible position-dependent thermophysical properties. Although the mathematical formulation is for moving solids, it can be used to study the heat transfer in a moving fluid with a non-uniform velocity distribution passing through a micro-channel or fluid-saturated porous ducts. Additionally, this presentation includes the application of this Green’s function solution to acquire numerical information for selected examples to further illustrate the numerical …

Residential Energy Performance Metrics, Christopher Wright, Stuart Werner Baur, Katie Grantham, Robert B. Stone, Scott Erwin Grasman

Engineering Management and Systems Engineering Faculty Research & Creative Works

Techniques for residential energy monitoring are an emerging field that is currently drawing significant attention. This paper is a description of the current efforts to monitor and compare the performance of three solar powered homes built at Missouri University of Science and Technology. The homes are outfitted with an array of sensors and a data logger system to measure and record electricity production, system energy use, internal home temperature and humidity, hot water production, and exterior ambient conditions the houses are experiencing. Data is being collected to measure the performance of the houses, compare to energy modeling programs, design and …

Impact Characteristics Of Nano Composites, Ammar Mohamed Al Omari

Theses

Nanocomposite materials have seen a significant increase in use and have created a revolution in high-performance structures. They exploit the properties of different materials which create structures that are stronger, stiffer, impact resistant and more durable against environmental factors. They can be tailored to have better electric, magnetic, optical properties, and be chemically, thermally and explosion resistant depending on the application. The current research study investigates the impact characteristics of polymeric based nanaocomposites strengthened with various types of nano and micro filler. An in-house designed impact testing machine was utilized to typify the impact characteristics of different nanocomposite materials through …

Constitutive Modeling Of Glassy Memory Polymers, Mahesh Khanolkar

Dissertations

The aim of this research is to develop constitutive models for non-linear materials. Here, issues related for developing constitutive model for glassy shape memory polymers are addressed in detail. Shape memory polymers are novel material that can be easily formed into complex shapes, retaining memory of their original shape even after undergoing large deformations. The temporary shape is stable and return to the original shape is triggered by a suitable mechanism such heating the polymer above a transition temperature. Glassy shape memory polymers are called glassy because the temporary shape is fixed by the formation of a glassy solid, while …

Transport Mechanisms And Modeling Of Riser Reactor, Dawei Wang

Dissertations

Riser reactors are extensively employed in various industrial applications. In a riser reactor, the hydrodynamics is closely interacted with kinetic reactions. Common models for the performance prediction of riser reactors overlook this vital coupling effect, which not only miss the important reaction characteristics in the dense-phase transport regime of riser reactors but also misinterpret the kinetic properties via ad hoc adjustments. It is noted that the modeling of hydrodynamics in riser flows has major flaws in its predictability of phase transport in both dense-phase and accelerating regimes where most reactions occur. In addition, with the spray feeding of reactants at …

Stochastic And Deterministic Dynamics Investigation Of The Microstructure Of Granular Materials, Vishagan Ratnaswamy

Theses

Granular materials are ubiquitous in one's daily life. They can be found in the cereal you eat, the sugar you put in your coffee or the sand you walk on in the beach. The study of granular materials has a rich history dating back to the 17th century where Kepler studied the packing of particles. The compaction of granular materials is a problem that is studied by using theory, experiments and simulations. While these studies have yielded some important results, there still are many details about the mechanisms of granular compaction that are unknown.

In this thesis, the density relaxation …

Optimization And Correlation Of The Penn State Model Of Friction Stir Welding To Experimental Welds In 304l Stainless Steel, Devin Donaldson Furse

Theses and Dissertations

A numerical model of friction stir welding developed by T. DebRoy, R. Nandan, and others has been optimized to fit experimental data of eleven welds of 304L stainless steel at various weld feed rates and spindle speeds. Optimization was used to determine the values of five difficult-to-measure model parameters. The optimal parameter values were then correlated to the weld machine inputs. The mechanical efficiency and the coefficient of friction were not correlated with feed rate, spindle speed, or axial pressure. Tool slip was positively correlated with feed rate, negatively correlated with spindle speed, and not correlated with axial pressure. The …

Application Of Structured Light Imaging For High Resolution Mapping Of Underwater Archaeological Sites, Chris Roman, Gabrielle Inglis, James Rutter

Graduate School of Oceanography Faculty Publications

This paper presents results from recent work using structured light laser profile imaging to create high resolution bathymetric maps of underwater archaeological sites. Documenting the texture and structure of submerged sites is a difficult task and many applicable acoustic and photographic mapping techniques have recently emerged. This effort was completed to evaluate laser profile imaging in comparison to stereo imaging and high frequency multibeam mapping. A ROV mounted camera and inclined 532 nm sheet laser were used to create profiles of the bottom that were then merged into maps using platform navigation data. These initial results show very promising resolution …

Design And Analysis Of A Compliant Mechanism Spinal Implant, Eric M. Stratton

Theses and Dissertations

This thesis introduces and presents the modeling of a novel compliant spinal implant designed to reduce back pain and restore function to degenerate spinal disc tissues as well as provide a mechanical environment conducive to healing the tissues. The initial objectives for this device development and the focus of this work are modeling and validation of the force-deflection relationships and stress analysis. Modeling was done using the pseudo-rigid-body model to create a 3 degree of freedom mechanism for flexion-extension (forward-backward bending) and a 5 degree of freedom mechanism for lateral bending (side-to-side). These models were analyzed using the principle of …

Uniaxially-Driven Controlled Biaxial Testing Fixture, Fadi K. Abu-Farha, Marwan K. Khraisheh

Mechanical Engineering Faculty Patents

A uniaxially-driven controlled biaxial testing fixture includes a base, a first coupler mounted to the base, and a load input drive rack mounted for linear movement with respect to the base. A second coupler and a first specimen grip are both mounted to the load input drive rack. Second, third and fourth specimen grips are also mounted for linear movement with respect to the base. First, second and third drive mechanisms connect the load input drive rack to the second, third and fourth specimen grips. Together the four specimen grips are oriented to provide biaxial application of force to a …

A One-Dimensional Finite-Difference Solver For Fully-Developed Pipe And Channel Flows, Doug F. Hunsaker

Utah Space Grant Consortium

An algorithm is developed to solve the fundamental flow cases of fully-developed turbulent flow in a pipe and in a channel. The algorithm uses second-order finite-difference approximations for nonuniform grid spacing and is developed in such a way as to easily facilitate the implementation of several two-equation, Reynolds-Averaged-Navier-Stokes turbulence models. Results are included for the Wilcox 1998 k-ω model.

High Strength And Light-Weight Materials Inspired By The Exoskeleton Of Arthropods, Anette M. Karlsson

Mechanical Engineering Faculty Publications

This work investigates the multiscaled structure and the constitutive behavior of the exoskeleton of arthropods (Japanese beetle) along with the response of biomimicked structures. Image analysis (SEM and TEM) revealed three load-bearing regions comprised of chitin-protein fiber layers orientated parallel to the cuticle surface. The chitin fibers in the exocuticle and mesocuticle are organized in a helicoidal structure (layers stacked with a small rotational angle relative to their adjacent layers). The endocuticle has a distinct pseudo-orthogonal pattern, characterized by a thin transitional helicoidal region inserted between two orthogonal layers. Idealized mechanics based models showed that the pseudo-orthogonal structure redistributes the …

Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syngas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

A tubular solid oxide fuel cell (SOFC) stack was modelled and its operation on biomass syn-gas was investigated. The objective of this work was to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack was modelled using Aspen Plus and considers ohmic, activation and concentration losses. It was validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor U_f and U_a, current density j and steam to carbon ratio STCR were varied and …

Validation Of A Simulation Model For A Combined Otto And Stirling Cycle Power Plant, Jim Mcgovern, Barry Cullen, Michel Feidt, Stoian Petrescu

Conference Papers

A project has been underway at the Technological University Dublin (DIT) to investigate the feasibility of a combined Otto and Stirling cycle power plant in which a Stirling cycle engine would serve as a bottoming cycle for a stationary Otto cycle engine. This type of combined cycle plant is considered to have good potential for industrial use. This paper describes work by DIT and collaborators to validate a computer simulation model of the combined cycle plant. In investigating the feasibility of the type of combined cycle that is proposed there are a range of practical realities to be faced and …

Gate 3 Grid Connection Group Processing Approach:An Analysis, John Leahy

Msc. in Energy Management

The aim of this project is to analyse the Group Processing Approach (the “GPA”) to renewable generator grid connections, and in particular the Gate 3 process which is the latest round of the GPA that is currently being implemented in the Republic of Ireland, to determine if it is the most effective approach for connecting new renewable generation. Gate 3 is the third series of the GPA for connecting renewable generation to the Irish Electricity grid where applications are processed in groups or batches. The size of the Gate 3 has bee capped at 3,900MW with applicants being selected based …

An Investigation Into The Retrofitting Of Air Source Heat Pumps Into Fabric Improved, Detached, Oil Centrally Heated Dwellings In Rural Ireland, Ciara Ahern

Other resources

In Ireland the predominant house type is detached housing which constitutes 43 % of entire stock. 72% of the detached housing stock is rurally located and 68% is heated by fuel oil. 82% of houses in Ireland have a radiator heating system. Detached housing, due to larger size and high surface area to volume ratio, has a greater heat loss per m² than all other house types of the same construction period. It follows that, if a heat pump can be successfully deployed in a house of this type it can be successfully deployed in almost all other house …

Turbine House: A Net-Zero Energy House, Karen E. Hernandez

Renée Crown University Honors Thesis Projects - All

Current use of fossil fuels has raised adverse problems in today’s society. The biggest one of them is the climate change caused by emissions of greenhouse gases. For this reason, renewable energies, or energy flows which are replenished at the same rate as they are used, are needed to reduce carbon emissions in the range of 60-80% by the end of the twenty-first century. [1] Energy used in houses nationwide contributes to 16% of generated greenhouse gas emissions. [3] This large percentage of greenhouse emissions could be reduced by designing and developing energy efficient houses, or net-zero energy houses, such …

In-Pile Thermal Conductivity Measurement Methods For Nuclear Fuels, Brandon S. Fox

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Measuring nuclear fuel thermal conductivity in-pile can provide much needed data for understanding fuel performance during irradiation and yield thermophysical property data needed for simulation codes and fuel databases. The objective of this research is to develop and compare two in-pile thermal conductivity methods in a laboratory setting using surrogate fuel materials.

A steady-state radial heat flow method was investigated to understand its viability as an in-pile steady-state thermal conductivity technique. By using Joule heating to simulate volumetric heat generation within a surrogate fuel rod, thermal conductivity was measured with two thermocouples at different radial positions within the rod. Examinations …

Guidance And Navigation Linear Covariance Analysis For Lunar Powered Descent, Travis J. Moesser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A linear covariance analysis is conducted to assess closed-loop guidance, navigation, and control system (GN&C) performance of the Altair vehicle during lunar powered descent. Guidance algorithms designed for lunar landing are presented and incorporated into the closed-loop covariance equations. Navigation-based event triggering is also included in the covariance formulation to trigger maneuvers and control dispersions. Several navigation and guidance trade studies are presented demonstrating the influence of triggering and guidance and study parameters on the vehicle GN&C performance.