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Full-Text Articles in Mechanical Engineering

Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu Aug 2019

Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu

Mechanical Engineering Research Theses and Dissertations

My research focuses on electrokinetic transport. Particularly, in this dissertation, we focus on fabrication and testing of micro electrodes with nanostructured surfaces to minimize the electrode polarization (EP) effects for biosensor applications. In the first study, electrochemical deposition of gold nanoparticles on to planar gold electrodes was used to generate rough surfaces. Dendritic nanostructures that reduced EP up to two orders of magnitude was obtained by optimizing the deposition conditions. These structures also enhanced dielectrophoresis (DEP) response of our bio-chips, making them usable in physiological buffers. In further studies we discovered a universal scaling of EP in the frequency domain ...


General Nonlinear-Material Elasticity In Classical One-Dimensional Solid Mechanics, Ronald Joseph Giardina Jr Aug 2019

General Nonlinear-Material Elasticity In Classical One-Dimensional Solid Mechanics, Ronald Joseph Giardina Jr

University of New Orleans Theses and Dissertations

We will create a class of generalized ellipses and explore their ability to define a distance on a space and generate continuous, periodic functions. Connections between these continuous, periodic functions and the generalizations of trigonometric functions known in the literature shall be established along with connections between these generalized ellipses and some spectrahedral projections onto the plane, more specifically the well-known multifocal ellipses. The superellipse, or Lam\'{e} curve, will be a special case of the generalized ellipse. Applications of these generalized ellipses shall be explored with regards to some one-dimensional systems of classical mechanics. We will adopt the Ramberg-Osgood ...


On The Feasibility Of Tailoring Copper-Nickel Functionally Graded Materials Fabricated Through Laser Metal Deposition, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk Aug 2019

On The Feasibility Of Tailoring Copper-Nickel Functionally Graded Materials Fabricated Through Laser Metal Deposition, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk

Frank W. Liou

In this study, pulse‐width modulation of laser power was identified as a feasible means for varying the chemical gradient in copper—nickel‐graded materials. Graded material deposits of 70 wt. %. copper‐30 wt. %. nickel on 100 wt. %. nickel and vice versa were deposited and characterized. The 70/30 copper—nickel weight ratio in the feedstock powder was achieved through blending elemental copper and 96 wt. %. Ni—Delero‐22 alloy. At the dissimilar material interface over the course of four layers, the duty cycle of power was ramped down from a high value to optimized deposition conditions. This change was ...


Functional Porous Polydimethlysiloxane As Piezoresistive And Piezoelectric Materials, Taissa Rose Michel Jul 2019

Functional Porous Polydimethlysiloxane As Piezoresistive And Piezoelectric Materials, Taissa Rose Michel

Theses and Dissertations

In this paper, polydimethylsiloxane (PDMS), carbon nanotubes (CNTs), and zinc oxide (ZnO) were combined to create functionalized piezoresistive and piezoelectric sensors for pressure sensing and energy harvesting. Samples were foamed to show that the increased deformability of the foam sensors makes them suitable for a range of applications including dexterous robotics, tactile sensing, energy harvesting, and biosensing. Uniform dispersion of CNTs was achieved with chloroform as the solvent. Samples were foamed using chemical blowing and scaffolding but granulated sugar at 70% porosity resulted in foamed samples with the most consistent mechanical properties. Samples underwent tensile and compressive testing for their ...


Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan Jul 2019

Investigation Of Fundamental Principles Of Rigid Body Impact Mechanics, Khalid Alluhydan

Mechanical Engineering Research Theses and Dissertations

In impact mechanics, the collision between two or more bodies is a common, yet a very challenging problem. Producing analytical solutions that can predict the post-collision motion of the colliding bodies require consistent modeling of the dynamics of the colliding bodies. This dissertation presents a new method for solving the two and multibody impact problems that can be used to predict the post-collision motion of the colliding bodies. Also, we solve the rigid body collision problem of planar kinematic chains with multiple contacts with external surfaces.

In the first part of this dissertation, we study planar collisions of Balls and ...


Experimental And Theoretical Evaluation Of The Effect Of Panel Geometry On The Failure Of Corrugated Board Panel, Takashi Takayama, Katsuhiko Saito, Akira Higashiyama Jun 2019

Experimental And Theoretical Evaluation Of The Effect Of Panel Geometry On The Failure Of Corrugated Board Panel, Takashi Takayama, Katsuhiko Saito, Akira Higashiyama

Journal of Applied Packaging Research

McKee’s formula is widely used to predict the compression strength (CS) of corrugated boxes and panels. It can accurately estimate the compression strength of boxes that are within a practical size range, but recently, larger and smaller corrugated boxes than before have been extensively developed. Therefore, there is a need for a CS prediction formula that works beyond the application range of McKee’s formula. Recent researches consider the failure mode as a combination of collapsing and buckling failure and remove the constraints and the assumptions associated with McKee’s formula. This makes it possible to more accurately estimate ...


Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen Jun 2019

Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen

Jonathan C. Claussen

Porous carbon is becoming an important and promising high-surface area scaffold material for various energy-based applications including catalysis. Here we demonstrate the growth of urchin-like platinum nanoparticles (PtNPs) on carbon monoliths derived from basswood that work as catalysts for micro underwater vehicle (MUV) propulsion via H2O2 decomposition. The carbon monoliths were constructed of natural basswood that was carbonized in argon (Ar) and subjected to a subsequent CO2 activation process that rendered the material into a hardened 3D porous activated carbonized wood (ACW) with inner channel voids measuring 10-70 μm in diameter. The PtNP nanourchins (500 nm or less in total ...


Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen Jun 2019

Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen

Shan Hu

Porous carbon is becoming an important and promising high-surface area scaffold material for various energy-based applications including catalysis. Here we demonstrate the growth of urchin-like platinum nanoparticles (PtNPs) on carbon monoliths derived from basswood that work as catalysts for micro underwater vehicle (MUV) propulsion via H2O2 decomposition. The carbon monoliths were constructed of natural basswood that was carbonized in argon (Ar) and subjected to a subsequent CO2 activation process that rendered the material into a hardened 3D porous activated carbonized wood (ACW) with inner channel voids measuring 10-70 μm in diameter. The PtNP nanourchins (500 nm or less in total ...


Dropwise Condensation On Multi-Scale Bioinspired Metallic Surfaces With Nano-Features, Daniel Orejon, Alexandros Askounis, Yasuyuki Takata, Daniel Attinger Jun 2019

Dropwise Condensation On Multi-Scale Bioinspired Metallic Surfaces With Nano-Features, Daniel Orejon, Alexandros Askounis, Yasuyuki Takata, Daniel Attinger

Daniel Attinger

Non-wetting surfaces engineered from intrinsically hydrophilic metallic materials are promising for self-cleaning, anti-icing and/or condensation heat transfer applications where the durability of the coating is an issue. In this work, we fabricate and study the wetting behaviour and the condensation performance on two metallic non-wetting surfaces with varying number and size of the roughness tiers without further hydrophobic coating procedure. On one hand, the surface resembling a rose petal exhibits a sticky non-wetting behaviour as drops wet the microscopic roughness features with the consequent enhanced drop adhesion, which leads to filmwise condensation. On the other hand, the surface resembling ...


Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen Jun 2019

Porous Wood Monoliths Decorated With Platinum Nano-Urchins As Catalysts For Underwater Micro-Vehicle Propulsion Via H2o2 Decomposition, Bolin Chen, Ahmed Gsalla, Anand Gaur, Yu Hui Lui, Xiaohui Tang, Jason Geder, Marius Pruessner, Brian J. Melde, Igor L. Medintz, Behrouz Shafei, Shan Hu, Jonathan C. Claussen

Mechanical Engineering Publications

Porous carbon is becoming an important and promising high-surface area scaffold material for various energy-based applications including catalysis. Here we demonstrate the growth of urchin-like platinum nanoparticles (PtNPs) on carbon monoliths derived from basswood that work as catalysts for micro underwater vehicle (MUV) propulsion via H2O2 decomposition. The carbon monoliths were constructed of natural basswood that was carbonized in argon (Ar) and subjected to a subsequent CO2 activation process that rendered the material into a hardened 3D porous activated carbonized wood (ACW) with inner channel voids measuring 10-70 μm in diameter. The PtNP nanourchins (500 nm or less in total ...


Dropwise Condensation On Multi-Scale Bioinspired Metallic Surfaces With Nano-Features, Daniel Orejon, Alexandros Askounis, Yasuyuki Takata, Daniel Attinger Jun 2019

Dropwise Condensation On Multi-Scale Bioinspired Metallic Surfaces With Nano-Features, Daniel Orejon, Alexandros Askounis, Yasuyuki Takata, Daniel Attinger

Mechanical Engineering Publications

Non-wetting surfaces engineered from intrinsically hydrophilic metallic materials are promising for self-cleaning, anti-icing and/or condensation heat transfer applications where the durability of the coating is an issue. In this work, we fabricate and study the wetting behaviour and the condensation performance on two metallic non-wetting surfaces with varying number and size of the roughness tiers without further hydrophobic coating procedure. On one hand, the surface resembling a rose petal exhibits a sticky non-wetting behaviour as drops wet the microscopic roughness features with the consequent enhanced drop adhesion, which leads to filmwise condensation. On the other hand, the surface resembling ...


Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li Jun 2019

Effect Of The Nonlinear Material Viscosity On The Performance Of Dielectric Elastomer Transducers, Yuanping Li

Electronic Thesis and Dissertation Repository

As a typical type of soft electroactive materials, dielectric elastomers (DEs) are capable of producing large voltage-induced deformation, which makes them desirable materials for a variety of applications in transduction technology, including tunable oscillators, resonators, biomimetics and energy harvesters. The dynamic and energy harvesting performance of such DE-based devices is strongly affected not only by multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, but also by their material viscoelasticity. Moreover, as suggested by experiments and theoretical studies, DEs possess nonlinear relaxation processes, which makes modeling of the performance of DE-based devices more challenging.

In this thesis ...


Modifying Casting Parameters To Improve The High Temperature Ductility Of Investment Cast Nickel-Based Superalloy Pwa 1455, Lars Alexander Hedin, Cole Magnum Introligator Jun 2019

Modifying Casting Parameters To Improve The High Temperature Ductility Of Investment Cast Nickel-Based Superalloy Pwa 1455, Lars Alexander Hedin, Cole Magnum Introligator

Materials Engineering

PCC Structurals, an industry leader in superalloy investment castings, has observed inconsistencies in the stress rupture performance of polycrystalline nickel-based superalloy PWA 1455. PCC has changed their casting parameters to reduce the thermal gradient during cooling but have been unable to correlate these changes with an increase in stress rupture elongation. Metallographic examination of past samples indicated microstructures composed of non- equiaxed dendritic grains with mean diameter of .021 inches along the test axis. A similar study on polycrystalline superalloys has indicated that excessive superheat temperatures above the liquidus can result in large grains identical to those observed, limiting the ...


Evaluation Of Tensile Properties For Selective Laser Melted 316l Stainless Steel And The Influence Of Inherent Process Features, Paul Swartz Jun 2019

Evaluation Of Tensile Properties For Selective Laser Melted 316l Stainless Steel And The Influence Of Inherent Process Features, Paul Swartz

Master's Theses and Project Reports

Optimal print parameters for additively manufacturing 316L stainless steel using selective laser melting (SLM) at Cal Poly had previously been identified. In order to further support the viability of the current settings, tensile material characteristics were needed. Furthermore, reliable performance of the as-printed material had to be demonstrated. Any influence on the static performance of parts in the as-printed condition inherent to the SLM manufacturing process itself needed to be identified. Tensile testing was conducted to determine the properties of material in the as-printed condition. So as to have confidence in the experimental results, other investigations were also conducted to ...


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 ...


Design Of Natural Composite I-Beam For Sampe 2019, Brian Harkness Jun 2019

Design Of Natural Composite I-Beam For Sampe 2019, Brian Harkness

Honors Theses

In recent years, the demand for high performance, lightweight, fiber-reinforced composites have grown substantially. Fiberglass and carbon fiber have exemplary material properties that meet the demand and have set the industry standard for performance materials. Although these materials meet their design function, they suffer from high environmental impacts throughout their life cycle and are not cost effective to produce. Flax fiber composites have comparable properties to fiberglass but can be produced more efficiently and production requires much less energy consumption. Flax is a readily available, renewable material that will easily biodegrade once it is the end of its useful life ...


Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin Jun 2019

Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin

Honors Theses

Structural health monitoring has the potential to allow composite structures to be more reliable and safer, then by using more traditional damage assessment techniques. Structural health monitoring (SHM) utilizes individual sensor units that are placed throughout the load bearing sections of a structure and gather data that is used for stress analysis and damage detection. Statistical time based algorithms are used to analyze collected data and determine both damage size and probable location from within the structure. While traditional calculations and life span analysis can be done for structures made of isotropic materials such as steel or other metals, composites ...


Investigation Of Nondestructive Testing Methods For Friction Stir Welding, Hossein Taheri, Margaret Kilpatrick, Matthew Norvalls, Warren Harper, Lucas Koester, Timothy Bigelow, Leonard J. Bond May 2019

Investigation Of Nondestructive Testing Methods For Friction Stir Welding, Hossein Taheri, Margaret Kilpatrick, Matthew Norvalls, Warren Harper, Lucas Koester, Timothy Bigelow, Leonard J. Bond

Electrical and Computer Engineering Publications

Friction stir welding is a method of materials processing that enables the joining of similar and dissimilar materials. The process, as originally designed by The Welding Institute (TWI), provides a unique approach to manufacturing—where materials can be joined in many designs and still retain mechanical properties that are similar to, or greater than, other forms of welding. This process is not free of defects that can alter, limit, and occasionally render the resulting weld unusable. Most common amongst these defects are kissing bonds, wormholes and cracks that are often hidden from visual inspection. To identify these defects, various nondestructive ...


Mechanical Properties And Applications Of Recycled Polycarbonate Particle Material Extrusion-Based Additive Manufacturing, Matthew J. Reich, Aubrey Woern, Nagendra Gautam Tanikella, Joshua M. Pearce May 2019

Mechanical Properties And Applications Of Recycled Polycarbonate Particle Material Extrusion-Based Additive Manufacturing, Matthew J. Reich, Aubrey Woern, Nagendra Gautam Tanikella, Joshua M. Pearce

Michigan Tech Publications

Past work has shown that particle material extrusion (fused particle fabrication (FPF)/fused granular fabrication (FGF)) has the potential for increasing the use of recycled polymers in 3D printing. This study extends this potential to high-performance (high-mechanical-strength and heat-resistant) polymers using polycarbonate (PC). Recycled PC regrind of approximately 25 mm2 was 3D printed with an open-source Gigabot X and analyzed. A temperature and nozzle velocity matrix was used to find useful printing parameters, and a print test was used to maximize the output for a two-temperature stage extruder for PC. ASTM type 4 tensile test geometries as well as ...


Design And Control Of Fiber Encapsulation Additive Manufacturing, Matt Saari May 2019

Design And Control Of Fiber Encapsulation Additive Manufacturing, Matt Saari

Mechanical Engineering Research Theses and Dissertations

This work presents the design, development, and analysis of the Fiber Encapsulation Additive Manufacturing (FEAM) system developed at the Laboratory for Additive Manufacturing Robotics \& Automation at the Lyle School of Engineering at Southern Methodist University. The innovation introduced by FEAM is the ability to insert a continuous fiber of different material into the flowing extrudate. Correctly positioning the fiber feed inside the extrudate while turning the fiber in arbitrary directions is a critical aspect of the technology. This will allow for the full exploitation of the capabilities of the FEAM technology to produce robotic components that actuate and sense. Several ...


Fracture Toughness Improvement Of ����� Ceramics By Grain Size Control And Ductile Phase Reinforcement, Kesong Wang May 2019

Fracture Toughness Improvement Of ����� Ceramics By Grain Size Control And Ductile Phase Reinforcement, Kesong Wang

Engineering and Applied Science Theses & Dissertations

This study used grain size control and ductile phase reinforcement to improve fracture toughness of ����� ceramics. Alpha alumina particles of 100 nm, 0.5-1 micrometers, and 10 micrometers were coated with 1-5 nm nickel by electroless nickel plating (ENP). The coated powders were consolidated at 1200℃-1500℃ by spark plasma sintering (SPS). The sintered samples were annealed at 1100 oC for 1.5 hours and 10 hours to determine the effect of post sintering annealing on hardness and fracture toughness. Density of the samples were measured by the standard Archimedes method using a 5 mL pycnometer. Hardness values were determined ...


Silicone Tadpole: Research Into Soft Bodies, Danielle Fernandez May 2019

Silicone Tadpole: Research Into Soft Bodies, Danielle Fernandez

Mechanical Engineering Undergraduate Honors Theses

In this thesis, research is conducted in the area of soft robotics by building a soft tadpole that can deform with a specific air pressure. The goal is to mimic the motion of an organic tadpole in respect to its S-shaped tail movement. The angle of deformation, derived from material mechanic theories, ranges from 45 to 80 degrees for this type of movement. The design includes a head compartment which acts as a tank to transfer nitrogen pressure and a tail section that receives the said pressure and bends as a result. The tail section was designed with two rows ...


Additive Manufacturing Of High Performance Flexible Thermoelectric Generators Using Nanoparticle Inks, Tony Valayil Varghese May 2019

Additive Manufacturing Of High Performance Flexible Thermoelectric Generators Using Nanoparticle Inks, Tony Valayil Varghese

Boise State University Theses and Dissertations

Flexible thermoelectric devices are attractive power sources for the growing demand of flexible electronics and sensors. Thermoelectric generators have an advantage due to no moving parts, silent operation and constant power production with a thermal gradient.

Conventional thermoelectric devices are rigid and fabricated using complex and relatively costly manufacturing processes, presenting a barrier to increase the market share of this technology. To overcome such barriers, this work focuses on developing near ambient-temperature flexible thermoelectric generators using relatively low-cost additive manufacturing processes. A screen printable ink was developed for transforming nanoparticle ink into high-performance flexible thermoelectric generators with a peak thermoelectric ...


The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok Apr 2019

The Effect Of Flinak Molten Salt Corrosion On The Hardness Of Hastelloy N, David Kok

Scholar Week 2016 - present

The Molten Salt Reactor (MSR) has been identified as a promising candidate to replace aging nuclear reactors around the world. However, a suitable combination of molten salt and container material needs to be found in order to reduce the potential for corrosion in the MSR before it can be considered commercially viable. FLiNaK molten salt and the nickel-based alloy Hastelloy N have been identified as prime candidates for this function, but the severity of FLiNaK corrosion in Hastelloy N requires additional study before this combination can be used in the operation of a MSR. In this study, Hastelloy N samples ...


Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu Apr 2019

Off Axis Compressive Response Of Ice-Templated Ceramics, Rahul Kumar Jujjavarapu

Mechanical & Aerospace Engineering Theses & Dissertations

The off-axis compressive behavior of ice-templated ceramic was analyzed using experimental results and micro-mechanical model simulation. Ice-templated ceramics is a versatile processing technique used to manufacture anisotropic ceramic foam by exploiting the anisotropic growth characteristics and lamellar morphology. The ice-templating process results in processing-structure-property relationships determined by the microstructure. The processed alumina samples which were later manufactured by water jet machine from the freeze casting were tested under quasi-static off-axis loading conditions and were used to determine the mechanical properties of the material. Digital image correlation (DIC) was used to measure the strain response of ice-templated ceramic under off-axis loading ...


Application Of Computational Tools To Spaghetti-Based Truss Bridge Design, Jin Xu, Jiliang Li, Nuri Zeytinoglu, Jinyuan Zhai Mar 2019

Application Of Computational Tools To Spaghetti-Based Truss Bridge Design, Jin Xu, Jiliang Li, Nuri Zeytinoglu, Jinyuan Zhai

ASEE IL-IN Section Conference

Application of Computational Tools to Spaghetti-Based Truss Design

Statics and Strength of Materials are two foundational courses for Mechanical/Civil Engineering. In order to assist students in better understanding and applying concepts to a meaningful design task, SolidWorks and theoretical calculation were used for a spaghetti-bridge design contest with the constraints of given maximum weight and allowable support-material weight. As the first step of this iterative designing process, both extrude feature and structural member were introduced to model planar bridge trusses. Then SolidWorks’ Statics module was used to run FEA analysis of the structural performance in efforts to optimize the ...


Design Of A Carburizing Treatment Of Steel Base Gear In The Materials Science Course, Jiliang Li, Jin Xu, Nuri Zeytinoglu, Jinyuan Zhai Mar 2019

Design Of A Carburizing Treatment Of Steel Base Gear In The Materials Science Course, Jiliang Li, Jin Xu, Nuri Zeytinoglu, Jinyuan Zhai

ASEE IL-IN Section Conference

Diffusion PDE Application to Carburizing Treatment of Steel Base Gear

An introductory materials-science course is required in the mechanical engineering curriculum of many universities. This article describes an example effort to incorporate programming, diffusion transfer, heat treatment process and mechanical-property determination as an integral part of the materials-science course instruction. This effort was undertaken in order to give students additional experience in Fick’s 1st and 2nd laws and in-depth understanding of physics and mathematics involved in diffusion analysis. We chose to focus on Fick’s second law because its applications are not restricted to the materials-science field ...


Process Parameter Development Of Additively Manufactured Af9628 Weapons Steel, Erin M. Hager Mar 2019

Process Parameter Development Of Additively Manufactured Af9628 Weapons Steel, Erin M. Hager

Theses and Dissertations

The manufacture of components in Additive Manufacturing processes is limited by the range of materials available. Qualification of materials for Additive Manufacturing is time intensive, and is often specific to a single type of machine. In this study, an approach to selecting power, speed, and hatch spacing values for a newly powderized material, AF9628 weapons steel, is described that results in highly dense (>99.9%) parts on an MLab 200R Cusing. Initial power and speed values used in a weld track study were selected based on a survey of parameters used on similar materials, with a focus on the energy ...


Microscale Metal Forming: Mesoscopic Size Effect, Extrusion And Molding, Bin Zhang Mar 2019

Microscale Metal Forming: Mesoscopic Size Effect, Extrusion And Molding, Bin Zhang

LSU Doctoral Dissertations

The continuing trend of metallic device and product miniaturization has motivated studies on microscale metal forming technologies. A better understanding of materials’ mechanical response and deformation behavior is of importance for the design and operation of micro metal forming processes. In this dissertation, uniaxial compression testing was conducted on Al ring and pillar specimens with characteristic dimensions at meso to micro scales. The experimental data reveal inadequacies of the existing surface layer model and provides a baseline for delineating deformation mechanisms in micro metal forming operations. Microscale reverse extrusion experiment was carried out on Cu and Al rod specimens with ...


Microwave Self-Healing Technology As Airfield Porous Asphalt Friction Course Repair And Maintenance System, Amir Tabakovic, Declan O'Prey, Drew Mckenna, David Woodward Mar 2019

Microwave Self-Healing Technology As Airfield Porous Asphalt Friction Course Repair And Maintenance System, Amir Tabakovic, Declan O'Prey, Drew Mckenna, David Woodward

Articles

A problem increasingly faced by airport authorities is the maintenance of runways. Due to their large aircraft loadings associated with take-off and landing operations, runways experience surface deterioration. Poor quality runway surfaces cannot be tolerated in such an environment. Maintenance issues must be carried out to maximise safety and minimise the risk of aircraft damage. A recent development has been the introduction of self-healing technologies such as rejuvenator encapsulation, induction and microwave heating to address these issues. This paper summarises a laboratory investigation to determine the effectiveness of microwave self-healing for crack repair of Porous Friction Course (PFC) used for ...