Elevated Test Pressure Significantly Reduces Dynamic Accumulation Oxygen Transmission Rate (Astm F3136) Measurement Time For Barrier Packaging Films, Bruce A. Welt
Journal of Applied Packaging Research
Measurement of gas transmission rates of materials is important for successful package design. The dynamic accumulation (DA) method (ASTM F3136) is becoming increasingly popular for measuring oxygen transmission rate (OTR) due to its simplicity and low cost. However, measurement time increases with barrier properties of materials, limiting measurement throughput. A dynamic accumulation measurement prototype capable of operating up to 1,000 psig was developed in order to accelerate gas transfer by boosting concentration gradients via elevated absolute pressures. Results show that measurement results were independent of test pressure while measurement times were substantially reduced. These results also suggest that gas ...
Electromechanical Coupling Behavior Of Dielectric Elastomer Transducers, 2015 The University of Western Ontario
Electromechanical Coupling Behavior Of Dielectric Elastomer Transducers, Jianyou Zhou
Electronic Thesis and Dissertation Repository
Dielectric elastomer transducers with large deformation, high energy output, light weight and low cost have been drawing great interest from both the research and industry communities, and shown potential for versatile applications in biomimetics, dynamics, robotics and energy harvesting. However, in addition to multiple failure modes such as electrical breakdown, electromechanical instability, loss-of-tension and fatigue, the performance of dielectric elastomer transducers are also strongly influenced by the hyperelastic and viscoelastic properties of the material. Also, the interplay among these material properties and the failure modes is rather difficult to predict. Therefore, in order to provide guidelines for the optimal design ...
Iron Pigments Through The Ages, 2015 Laval University, Quebec City, Canada
Iron Pigments Through The Ages, Fathi Habashi
Naturally occurring iron oxides were used since ancient times as ochre yellow and red pigments. It was only in the 18th century that artificially prepared Prussian blue was discovered. This discovery opened up a new field of chemistry - - cyano compounds.
Rail Squats: Understand Its Causes, Severity, And Non-Destructive Evaluation Techniques, 2015 University of Birmingham
Rail Squats: Understand Its Causes, Severity, And Non-Destructive Evaluation Techniques, Sakdirat Kaewunruen, Makoto Ishida
Generally, rail squats are defined by the growth of any cracks that have grown longitudinally through the rail subsurface and some of the cracks propagating to the bottom of rails transversely have branched from initial longitudinal cracks with a depression of rail surface. The rail defects are commonly referred to as ‘squats’ when they were initiated from damage caused by rolling contact fatigue, and as ‘studs’ when they were associated with white etching layer caused by the transform from pearlitic steel due to friction heat generated by wheel sliding or excessive traction. Such rail surface defect induces wheel/rail impact ...
Achieving Carbon Efficiency In Construction And Maintenance Of Railway Turnouts, Crossovers And Diamonds, 2015 University of Birmingham
Achieving Carbon Efficiency In Construction And Maintenance Of Railway Turnouts, Crossovers And Diamonds, Sakdirat Kaewunruen, Steve Krezo, Olivia Mirza, Yapping He, Joseph M. Sussman
Railway turnouts, crossovers, and diamonds are special track systems used to divert a train from a particular direction or a particular track onto other directions or other tracks. It is a structural grillage system that consists of steel rails, points, crossings, steel plates, rubber pads, insulators, fasteners, screw spikes, beam bearers (either timber, polymer, steel or concrete), ballast and formation. Usually under dynamic and high-intensity impact loading conditions, structural components of the turnout tend to have relatively short lives compared with those of ordinary open railway tracks, resulting in frequent turnout re- construction and maintenance (ranging from every 10 to ...
Severity And Growth Evaluation Of Rail Corrugations On Sharp Curves Using Wheel/Rail Interaction, 2015 University of Birmingham
Severity And Growth Evaluation Of Rail Corrugations On Sharp Curves Using Wheel/Rail Interaction, Sakdirat Kaewunruen, Steve Marich
A railway network generally spans over a large distance so the structural health monitoring of such a rail infrastructure system is one of the critical challenges in rail industry practice. Especially in an underground/subway or elevated system, the facilities, resources and time period permitted for critical infrastructure inspection and maintenance is considerably limited. As a result, the automated inspection system of railway is in very high demand. Rail corrugation defect is the periodic, undulated or wave-like vertical alignment of rail surface. The wavelength and severity of rail corrugations is dependant to track structure, track geometry, traction system, rail vehicle ...
Design Of Holes And Web Openings In Railway Prestressed Concrete Sleepers, 2015 University of Birmingham
Design Of Holes And Web Openings In Railway Prestressed Concrete Sleepers, Erosha Kahawatta Gamage, Sakdirat Kaewunruen, Alex M. Remennikov
As the crosstie beam in railway track systems, the prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed concrete has played a significant role as to maintain the high endurance of the sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed concrete sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of concrete sleepers. For ...
Under Sleeper Pads: Field Investigation Of Their Role In Detrimental Impact Mitigation, 2015 University of Birmingham
Under Sleeper Pads: Field Investigation Of Their Role In Detrimental Impact Mitigation, Sakdirat Kaewunruen, Alex M. Remennikov
Under sleeper pads (USPs) are the component installed under the concrete sleepers generally to improve railway track resilience. Initial development in Europe, particularly in Austria, has encouraged the adoption of the component around the world. In practice, the component has commonly been used in certain applications, mainly to moderate track stiffness in special locations such as turnouts, crossings, and level crossing. In heavy haul operation, the heavier wagons result in sturdier bogie structures, higher unsprung mass, and then higher level of wheel-rail interaction forces. Accordingly, the application of USPs to mitigate detrimental impact load consequence on track structure is presented ...
Resilience-Based Design Of Precast Steel-Concrete Composites For Railway Track Slabs, 2015 University of Birmingham
Resilience-Based Design Of Precast Steel-Concrete Composites For Railway Track Slabs, Sakdirat Kaewunruen, Dane Wp Griffin, Olivia Mirza, Kenny Kwok
The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as ...
Analysis Of A Carbon Fiber Reinforced Polymer Impact Attenuator For A Formula Sae Vehicle Using Finite Element Analysis, 2015 California Polytechnic State University - San Luis Obispo
Analysis Of A Carbon Fiber Reinforced Polymer Impact Attenuator For A Formula Sae Vehicle Using Finite Element Analysis, John T. Rappolt
Master's Theses and Project Reports
The Hashin failure criteria and damage evolution model for laminated fiber reinforced polymers are explored. A series of tensile coupon finite element analyses are run to characterize the variables in the physical model as well as modeling techniques for using an explicit dynamic solver for a quasi-static problem. An attempt to validate the model on an axial tube crush is presented. It was found that fiber buckling was not occurring at the impactor-tube interface. Results and speculation as to why the failure initiation is incorrect are discussed. Lessons learned from the tube crush are applied successfully to the quasi-static Formula ...
Movement Of Scientists And The Production Of Aluminum, 2015 Laval University, Quebec City, Canada
Movement Of Scientists And The Production Of Aluminum, Fathi Habashi
Travelling scientists certainly have contributed to advancing knowledge by communicating their observations to others. Famous professors attract students from different countries to study in their institutions and the interaction among these students is of immense importance in the diffusion of knowledge. The invention of a process for the production of aluminum is an example.
Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, 2015 University of Florida
Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric Mclamore, Arthur Teixeira, Sanjay Shukla
Journal of Applied Packaging Research
Methods for creating precise perforations in respiring produce packaging are being increasingly adopted. Knowledge of oxygen transfer through perforated packaging and oxygen distribution in packages is necessary for successful packaging design of fresh produce. An approach to modeling perforated packaging performance was developed using a cylindrical chamber with precision perforations using Fick’s second law. The model was simulated using two techniques including Finite Element Method (FEM) using commercially available software and Finite Volume Method (FVM) through programming. Perforations were approximated as a source term in the second method. Both simulation techniques showed trends similar to experimental data.
Impact Responses Of Prestressing Tendons In Railway Concrete Sleepers In High Speed Rail Environments, 2015 University of Birmingham
Impact Responses Of Prestressing Tendons In Railway Concrete Sleepers In High Speed Rail Environments, Sakdirat Kaewunruen, Alex M. Remennikov
Prestressed concrete sleepers (or railroad ties) are designed in order to carry and transfer the wheel loads from the rails to the ground and are installed as the crosstie beam support in railway track systems. They are subjected to impact loading conditions that are resulted from train operations over wheel or rail abnormalities, such as flat wheels, dipped rails, crossing transfers, rail squats, corrugation, etc. The magnitude of the shock load relies on various factors such as axle load, types of wheel/rail imperfections, speeds of vehicle, track stiffness, etc.
This paper demonstrates the development of finite element modelling to ...
Characterizing Water As Gap Fill For Double Glazing Units, 2015 Western Kentucky University
Characterizing Water As Gap Fill For Double Glazing Units, Bright Adu
Masters Theses & Specialist Projects
The use of sunlight has always been a major goal in the design and operation of commercial buildings to minimize electrical consumption of artificial lighting systems. Glazing systems designed to allow optimal visible light transmission also allow significant unwanted direct solar heat gain caused by infrared light. Conversely, glazing systems that are designed to reflect unwanted direct solar heat gain significantly reduce the transmittance of visible light through windows. The goal of this research was to characterize the performance of water as gap-fill for double-glazing units in eliminating the compromises that exist in current glazing systems with respect to light ...
Impact Of Fuel Rod Coatings On Reactor Performance And Safety, 2015 University of Tennessee - Knoxville
Impact Of Fuel Rod Coatings On Reactor Performance And Safety, Ian Robert Stewart
This study evaluates the use of a ceramic coating on the Zr-alloy cladding within a PWR using four ceramic compounds of 5 and 10 micron thicknesses: ZrO2, TiAlN, Ti2AlC, and Ti3AlC2. The film’s impact is assessed for variation on: reactivity, fuel cycle length, maximum temperature, film’s roughness, and transient conditions. The reactivity is analyzed using the following methods: change in the multiplication factor (k) each film introduces to the system using the ABH method, and Monte Carlo software (MCNP). Both methods are in good agreement, yielding less than half a percent change from a reference, no-film fuel pin ...
Phase Dynamics Of Locset Control Methodology, 2015 University of Tennessee - Knoxville
Phase Dynamics Of Locset Control Methodology, Brendan Neschke
Single-mode fiber amplifiers produce diffraction-limited beams very efficiently. Maximum beam intensity requires that an array of these amplifiers have their beams coherently combined at the target. Optical path differences and noise adversely affect beam quality. An existing closed loop phase control methodology, called the locking of optical coherence by single-detector electronic-frequency tagging (LOCSET), corrects phase errors in real time by electronically detecting path length differences and sending signals to lithium niobate phase adjusters. Broadening the line-width using “jitter” of the input signal can increase the output power of an individual amplifier by suppressing nonlinearity. The system dynamics of LOCSET are ...
Development Of An Efficient Data Processing Procedure For The Prediction Of Cleavage Fracture In Reactor Pressure Vessel Steels Using The J-A2 Method, 2015 University of Tennessee - Knoxville
Development Of An Efficient Data Processing Procedure For The Prediction Of Cleavage Fracture In Reactor Pressure Vessel Steels Using The J-A2 Method, Phoebe E. Fogelman
University of Tennessee Honors Thesis Projects
No abstract provided.
Energy Selective Neutron Imaging For The Characterization Of Polycrystalline Materials, 2015 University of Tennessee - Knoxville
Energy Selective Neutron Imaging For The Characterization Of Polycrystalline Materials, Robin Woracek
This multipart dissertation focuses on the development and evaluation of advanced methods for material testing and characterization using neutron diffraction and imaging techniques. A major focus is on exploiting diffraction contrast in energy selective neutron imaging (often referred to as Bragg edge imaging) for strain and phase mapping of crystalline materials. The dissertation also evaluates the use of neutron diffraction to study the effect of multi-axial loading, in particular the role of applying directly shear strains from the application of torsion. A portable tension-torsion-tomography loading system has been developed for in-situ measurements and integrated at major user facilities around the ...
Dynamic Simulation And Neuromuscular Control Of Movement: Applications For Predictive Simulations Of Balance Recovery, 2015 University of Tennessee - Knoxville
Dynamic Simulation And Neuromuscular Control Of Movement: Applications For Predictive Simulations Of Balance Recovery, Misagh Mansouri Boroujeni
Balance is among the most challenging tasks for patients with movement disorders. Study and treatment of these disorders could greatly benefit from combined software tools that offer better insights into neuromuscular biomechanics, and predictive capabilities for optimal surgical and rehabilitation treatment planning. A platform was created to combine musculoskeletal modeling, closed-loop forward dynamic simulation, optimization techniques, and neuromuscular control system design. Spinal (stretch-reflex) and supraspinal (operational space task-based) controllers were developed to test simulation-based hypotheses related to balance recovery and movement control. A corrective procedure (rectus femoris transfer surgery) was targeted for children experiencing stiff-knee gait and how this procedure ...
High Pressure Behavior Of Mullite-~Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility And Microstructural Implications, 2015 University of Nevada, Las Vegas
High Pressure Behavior Of Mullite-~Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility And Microstructural Implications, Patricia Kalita
UNLV Theses/Dissertations/Professional Papers/Capstones
Even though mullite occurs rarely in nature, it is perhaps one of the most important phases in both traditional and advanced ceramics. Existing and emerging applications of mullite and mullite-type materials include: high-temperature composites, aerospace materials, ballistic shielding for military applications and even non-linear optical materials. There are many uncertainties regarding the basic physical properties of mullite-type materials, particularly in terms of their high-pressure structural stability and mechanical behavior that are important to address for emerging applications of mullites as engineering materials. This work is the first reported comprehensive investigation of the high –pressure structural behavior of several different mullites ...