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Articles 1 - 26 of 26
Full-Text Articles in Mechanical Engineering
Fixed Platform Crane For Equipment Access, Carlos Gonzalez, Steven Hollander, Yue Zhao, Jared Pellegrin, Travis Odom
Fixed Platform Crane For Equipment Access, Carlos Gonzalez, Steven Hollander, Yue Zhao, Jared Pellegrin, Travis Odom
Honors Theses
No abstract provided.
Energy Dissipation And Entropy Generation During The Fatigue Degradation: Application To Health Monitoring Of Composites, Ali Kahirdeh
Energy Dissipation And Entropy Generation During The Fatigue Degradation: Application To Health Monitoring Of Composites, Ali Kahirdeh
LSU Doctoral Dissertations
In this dissertation, an experimental approach for characterizing energy dissipation and degradation evolution in a woven Epoxy/Glass (G10/FR4) laminate subjected to fully reversed bending fatigue test is presented. Infrared thermography and acoustic emission are utilized to characterize the degradation progression. The results show similar evolutionary response indicating the presence of three degradation stages. The effect of the surface cooling on the fatigue life of the laminates is investigated both experimentally and analytically. The results show that the life of the laminate is highly dependent on the temperature and that surface cooling can significantly increase the fatigue life of the laminate. …
The Effects Of Asymmetric Micro Ratchets On Pool Boiling Performance, Lance Austin Brumfield
The Effects Of Asymmetric Micro Ratchets On Pool Boiling Performance, Lance Austin Brumfield
LSU Doctoral Dissertations
Nucleate boiling is an attractive method for achieving high heat flux at low superheat temperatures. It is frequently used for industrial applications such as heat exchangers and is being considered to cool advanced central processing units (CPU) which produce heat fluxes on the order of 1 MW/m2 and are becoming increasingly less efficient to cool via forced conduction of air. The issue with implementing nucleate boiling as a cooling mechanism lies in the difficulty of quantifying the numerous and complex mechanisms which control the process. A comprehensive nucleate boiling model has yet to be formulated and will be required in …
A Parametric Investigation Of A Novel, Modular, Gasketless, Microfluidic Interconnect Using Parallel Superhydrophobic Surfaces, Christopher Ramsey Brown
A Parametric Investigation Of A Novel, Modular, Gasketless, Microfluidic Interconnect Using Parallel Superhydrophobic Surfaces, Christopher Ramsey Brown
LSU Master's Theses
The gasketless microfluidic interconnect has the potential to offer a standardized approach to interconnects between modular microfluidic components. This strategy uses parallel superhydrophobic surfaces (contact angle ≥ 150ᴼ) to passively seal adjacent, concentric, microfluidic ports separated by an air gap using a liquid bridge created between the chips. The parallel superhydrophobic surfaces do not require the addition of a gasket or other additional components so that the assembly process scales favorably with an increasing number of fluidic interconnects. The gasketless seal does not contribute to geometric constraint between the component chips which allows alignment between chips to scale favorably with …
Crack Self-Healing In Sic/Spinel Nanocomposite, Fariborz Tavangarian
Crack Self-Healing In Sic/Spinel Nanocomposite, Fariborz Tavangarian
LSU Doctoral Dissertations
Spinel is one of the best known and widely used ceramic materials. It has good thermal shock resistance, high chemical inertness in both acidic and basic environments, excellent optical and dielectric properties, high strength at both elevated and normal temperatures, and has no phase transition up to the melting temperature (2135°C). Spinel is used in the metallurgical, electrochemical, and chemical industrial fields. It has also found some applications in dentistry, catalyst supports, humidity sensors, reinforcing fibers, photoluminescent materials, etc. One of the limitations of spinel ceramic is its brittleness. Furthermore, at high temperature applications, a rapid heating or cooling can …
Novel Syntheses And Surface Modifications Of Electrode Materials For Superior Lithium-Ion Batteries, Jianqing Zhao
Novel Syntheses And Surface Modifications Of Electrode Materials For Superior Lithium-Ion Batteries, Jianqing Zhao
LSU Doctoral Dissertations
Rechargeable lithium-ion battery is one of the most promising energy conversion and storage systems that offers high energy and powder densities, long service life and assuring safety. Performance of lithium-ion batteries crucially relies on electrochemical characteristics of electrode materials, i.e., anode and cathode materials. This dissertation work aims at developing novel electrode materials with high capacity, excellent cycling stability and remarkable rate capability for next-generation lithium-ion batteries. The effects of surface modifications for LiMn2O4 cathode materials are studied by depositing ultrathin conformal amphoteric oxides via atomic layer deposition (ALD). In the case of ZnO coating, the thickness of ZnO ALD …
Fabrication And Enhancement Of Aluminum-Based Microchannel Devices, Paul Joseph Hymel
Fabrication And Enhancement Of Aluminum-Based Microchannel Devices, Paul Joseph Hymel
LSU Master's Theses
Microscale molding replication and transient liquid phase (TLP) bonding were used to fabricate Al-based microchannel heat exchangers (MHEs) and micro gas chromatograph (mGC) columns. Metal-based microchannel heat exchangers often experience corrosion as a result of their operating conditions. To address this problem, an internal anodization method was developed in Al microtubes by pulsing the flow of electrolyte through a microtube when the current dropped below a set value. The anodic aluminum oxide (AAO) films were characterized by scanning electron microscopy (SEM), focused ion beam (FIB) cross sections, and X-ray energy dispersive spectroscopy (EDS) to determine their growth rate and morphology. …
An Experimental Investigation Of Corrosion Fatigue Life Via Thermographic Method, Richard Wayne Purvis
An Experimental Investigation Of Corrosion Fatigue Life Via Thermographic Method, Richard Wayne Purvis
LSU Master's Theses
The effect of prior corrosion fatigue damage on the thermographic response of 1018 low carbon steel is investigated. Specimens were subject to rotating bending fatigue at 38 Hz loading frequency while being exposed to a 3.5% NaCl and distilled water solution. Some specimens were subject to corrosion fatigue for part of their fatigue life and then their thermographic response measured under fatigue in air at 62 Hz loading frequency. Fatigue tests in air with thermographic measurement were performed as a comparison. It was observed that the initial temperature rise after corrosion fatigue fits the previously proposed model for air fatigue, …
Utilization Of Carbon Nanofibers Grown On Glass Microballoons (Nmbs) In Point-Of-Care Diagnostic Devices, Emmanuel Gikunoo
Utilization Of Carbon Nanofibers Grown On Glass Microballoons (Nmbs) In Point-Of-Care Diagnostic Devices, Emmanuel Gikunoo
LSU Doctoral Dissertations
The use of point-of-care (POC) diagnostic systems holds great promise for the early detection of various diseases. However, detection limits for commercially available POC systems have not been able to meet the lower cutoffs offered by the specialized laboratory testing methods. Research into the use of carbon nanofibers (CNFs) grown on glass microballoons in POC devices was studied. The growth of several millions of the CNFs on each microballoon (NMBs) presented a large surface area with high probability of capturing minute concentrations of biospecies. Functionalization of the NMBs with the carboxyl group needed for biospecies conjugation was achieved by air …
Meso-Scale Analysis Of Deformation Induced Heating In Granular Metalized Explosives By Piston Supported Waves, Sunada Srinath Nagamani Chakravarthy
Meso-Scale Analysis Of Deformation Induced Heating In Granular Metalized Explosives By Piston Supported Waves, Sunada Srinath Nagamani Chakravarthy
LSU Doctoral Dissertations
Shock sensitivity of heterogeneous explosive composites is dependent on the formation of hot-spots which are small regions of elevated temperatures within the material. Changes in the initial meso-structure (i.e. packing density, composition, particle size and shapes) of the explosives can significantly alter the hot-spot fields in the material and thereby affect its shock sensitivity. In this study, an explicit, 2D, Lagrangian finite and discrete element technique is used to numerically simulate the deformation induced heating of granular mixtures of explosive (HMX), and metal (Al) particles due to piston supported uniaxial deformation waves (400 ≤ Up ≤ 800 m/s). A number …
Hot Corrosion Behaviour Of New Candidates For Thermal Barrier Coatings Application In Turbine Simulated Environments, Mohammad Hamed Habibi
Hot Corrosion Behaviour Of New Candidates For Thermal Barrier Coatings Application In Turbine Simulated Environments, Mohammad Hamed Habibi
LSU Doctoral Dissertations
Thermal barrier coatings (TBCs) are used gas turbine engines. The current material of choice (YSZ) degrades when it contacts with impurities arise from low quality fuels such vanadium and sulfur. YSZ cannot be used in temperature higher than 900˚C. Higher efficiency and performance of gas turbine engines will require a new generation of thermal barrier coatings (TBCs). In current work, hot corrosion behavior of new candidates including Gd2Zr2O7, ZrO2 stabilized with Ta2O5, zirconia stabilized with both Ta2O5 and Y2O3 and zirconia stabilized with CeO2 and TiO2 is investigated. For YSZ case, the reaction between NaVO3 and Y2O3 produces YVO4 and …
Novel Nanostructured Titania And Titania Nanocomposites For Photovoltaics And Photocatalysis, Xinning Luan
Novel Nanostructured Titania And Titania Nanocomposites For Photovoltaics And Photocatalysis, Xinning Luan
LSU Doctoral Dissertations
With the consumption of energy continually increasing around the world and the main source of this energy, fossil fuels, slowly being depleted, the need for alternate sources of energy is becoming more and more pertinent. Demand for solar energy has experienced exponential increase over the last decade. Nanostructured TiO2 has attracted significant attention due to its nontoxicity, low cost and wide applications in photovoltaics and photocatalysis. This research is focused on novel synthesis and surface modification of TiO2 nanotube arrays for applications in advanced dye-sensitized solar cells (DSSCs) and efficient photocatalysis. The first part of this work entails fast synthesis …
Energy And Thermodynamically Based Approaches For Analysis Of Damage In Contact Problems, Afshin Babaie Aghdam
Energy And Thermodynamically Based Approaches For Analysis Of Damage In Contact Problems, Afshin Babaie Aghdam
LSU Doctoral Dissertations
A novel methodology for analysis of damage in contact problems in presented. Two important categories of contact damage are studied, namely crack nucleation and adhesive wear. The proposed methodology is primarily based on the laws of energy and thermodynamics, and as such offers great advantages by unifying the analysis of damage in a variety of contact configurations. Crack nucleation is the first damage type analyzed. For this purpose, the line-contact fretting configuration is chosen. A thermodynamically-based continuum damage mechanics (CDM) approach is employed. Intense stress gradients in the contact region are found to be highly influential in the crack nucleation …
Analyses Of Online Monitoring Signals For A Gmaw Process Before And After Improvement, Aniruddha Joshi
Analyses Of Online Monitoring Signals For A Gmaw Process Before And After Improvement, Aniruddha Joshi
LSU Master's Theses
The ability to detect the onset of welding instability is a very powerful tool in welding process monitoring and control. Toward this goal, this study investigates a gas metal arc welding (GMAW) process by analyzing online monitoring signals. Two separate data sets are obtained from the process, which correspond to (a) a stable process after improvement and (b) a relatively unstable process which tends to exhibit spatter and poor weld bead geometry. Voltage, current, wire-feeding speed and line speed signals for both data sets are analysed and features are extracted from the raw signals using different signal processing techniques. Specifically, …
Composition Control Of Spinel Lithium Manganese Oxide For High Voltage, High Energy Lithium Ion Batteries, Hilary Eikhuemelo
Composition Control Of Spinel Lithium Manganese Oxide For High Voltage, High Energy Lithium Ion Batteries, Hilary Eikhuemelo
LSU Master's Theses
In the quest for renewable source of energy, a remarkable step made was in the introduction of the battery system. The lithium ion battery was revolutionary in this regard particularly for its light weight and high energy density. There has been significant progress in the development of this battery system since the present form was introduced in the 1990s. There is currently a global dependence on the use of lithium ion battery in diverse applications such as in the electronics, communications and automobiles. Unfortunately, the energy obtainable from the lithium ion battery continuously falls behind the energy demand. This setback …
A Thermographic Method For Remaining Fatigue Life Prediction Of Welded Joints, Paul Thomas Williams
A Thermographic Method For Remaining Fatigue Life Prediction Of Welded Joints, Paul Thomas Williams
LSU Master's Theses
A non-destructive thermographic technique is adapted and applied to study the fatigue life and behavior of welded specimens made from two different materials. Results show good agreement between experimental predictions of consumed fatigue life and predicted fatigue life. Further, the thermal evolution of the specimens is used to calculate Damage Parameter, which is also used to make fatigue life predictions with promising results. To gain further insight Buckingham Pi theorem is also applied to determine the role of the important parameters involved in a dimensionless form. For this purpose, a series of experiments were performed and used for the analysis …
Using A Sleep And Activity Monitor To Operationalize Fatigue Risk Management, Vanessa Bégat Seitz
Using A Sleep And Activity Monitor To Operationalize Fatigue Risk Management, Vanessa Bégat Seitz
LSU Master's Theses
When a person continues to work despite being fatigued, an accident may occur or productivity may decrease. Reducing fatigue related accidents is complicated due to the subjective nature and pervasiveness of the feeling of fatigue. Because finding one universal definition or measure of fatigue is problematic, fatigue is typically measured by a combination of factors such as amount of sleep obtained, physical or cognitive work performed, or sleepiness which can then be related back to a measure of performance. Until recently, sleep measurement was restricted to a lab setting; however, with the emergence of actigraph devices, it is now possible …
Assessing The Effects Of Work Zone Configurations On Drivers' Visual Attention, Karthy Punniaraj
Assessing The Effects Of Work Zone Configurations On Drivers' Visual Attention, Karthy Punniaraj
LSU Master's Theses
This study assessed the effects of two different work zone configurations on driver’s visual attention by eye movement monitoring. A driving simulator study was conducted with thirty participants. Variations in traffic density and warning sign placement distance were added to the merge configurations to simulate the real time situation. A 2 x 2 x 3 within-subjects factorial design was used for this research. The independent variables used in this study were (1) merge configuration [(i) Conventional Lane Merge (CLM) and (ii) Joint Lane Merge (JLM)], (2) traffic density [(i) high and (ii) low] and (3) distance between traffic signs [(i) …
Influence Of Magnetic Fields On The Evaporation And Combustion Of A Single Droplet, Domingo Elias
Influence Of Magnetic Fields On The Evaporation And Combustion Of A Single Droplet, Domingo Elias
LSU Master's Theses
The reliance on combustion as the primary source of energy will continue in the US for the next thirty years [1]. Experiments suggest that the use of magnetic fields can be one tool in the many-sided approach to the problem of environmental protection and energy conservation in the US. For instance, it is estimated that an increase in efficiency of 2% in spray combustion can save the US economy billions of dollars [2]. In this thesis I report on improving the quality of combustion through the use of magnetic fields. (1)I investigated the effects of magnetic fields on the evaporation …
Innovative Heat Transfer Augmentation Techniques In Mechanical Face Seal, Nian Xiao
Innovative Heat Transfer Augmentation Techniques In Mechanical Face Seal, Nian Xiao
LSU Doctoral Dissertations
Excessive heat generated at the face seal contact interface has been recognized as one of main causes of failure of mechanical seals. In the past few decades various efforts have been attempted to remove heat from the contact interface uniformly in order to reduce the interfacial temperature, eliminate thermally-induced failure, and thus increase the life of a mechanical seal. Two innovative heat transfer augmentation techniques - surface texturing and built-in phase change device - have been developed in our laboratory to effectively enhance the heat transfer in mechanical face seal. Surface texturing can increase the surface area, change the near …
Age, Performance And Retention Interval Effects On Acceptance Of A Consumer Health Information Technology System, Stephen Andrew Ford
Age, Performance And Retention Interval Effects On Acceptance Of A Consumer Health Information Technology System, Stephen Andrew Ford
LSU Master's Theses
The older adult population will continue to place pressure on the financial and resource allocation of the healthcare industry as the over 65 population continues to grow. Health care expenditures to treat the aging population will continue to rise as older adults are more likely to have expensive chronic conditions. The future may lay with Consumer Health Information Technology which may allow the patients to have more control of their treatment schedule and self-management of their health and chronic conditions. However, older adults may exhibit cognitive declines that prohibit the learning and proper use of technology, and this assumption is …
Minimization Of Transportation, Installation And Maintenance Operations Costs For Offshore Wind Turbines, Tasnim Ibn Faiz
Minimization Of Transportation, Installation And Maintenance Operations Costs For Offshore Wind Turbines, Tasnim Ibn Faiz
LSU Master's Theses
Although it is a sustainable source and there is abundant potential for energy, cost of energy generated from offshore wind is still high compared to other sustainable energy sources. Apart from the manufacturing cost of turbines, cost of energy is significantly affected by costs of transportation and installation operations of wind turbines and maintenance operations of turbine components. Through optimum selection of decision variables, such as turbine installation method and rated power output of each turbine, cost of transportation and installation operations can be minimized. The first model in this study investigates the impact of these decision variables and effect …
Applications Of The Variational Approach To Fracture Mechanics, Ataollah Mesgarnejad
Applications Of The Variational Approach To Fracture Mechanics, Ataollah Mesgarnejad
LSU Doctoral Dissertations
In this study we present the variational approach to fracture mechanics as a versatile tool for the modeling of the fracture phenomenon in solids. Variational fracture mechanics restates the problem of initiation and propagation of cracks in solids as an energy minimization problem. The edifice of this energy minimization problem is such that unlike other methods (e.g. extended finite element method XFEM, cohesive-zone methods) the variational approach to fracture mechanics, diminishes the need for an a priori knowledge of the crack path or ad hoc assumptions in the form of path selection laws. We will show applications of the variational …
Tomographic Imaging Of Combustion Zones Using Tunable Diode Laser Absorption Spectroscopy (Tdlas), Avishek Guha
Tomographic Imaging Of Combustion Zones Using Tunable Diode Laser Absorption Spectroscopy (Tdlas), Avishek Guha
LSU Doctoral Dissertations
This work concentrates on enabling the usage of a specific variant of tunable diode laser absorption spectroscopy (abbr. TDLAS) for tomogaphically reconstructing spatially varying temperature and concentrations of gases with as few reconstruction artifacts as possible. The specific variant of TDLAS used here is known as wavelength modulation with second harmonic detection (abbr. WMS-2f) which uses the wavelength dependent absorbance information of two different spectroscopic transitions to determine temperature and concentration values. Traditionally, WMS-2f has generally been applied to domains where temperature although unknown, was spatially largely invariant while concentration was constant and known to a reasonable approximation (_x0006_+/- 10% …
Association Of Lean Implementation On Perceived Organizational Maturity Levels Of Managers And Staff In The Public Sector, Patrick Eduardo O'Mara
Association Of Lean Implementation On Perceived Organizational Maturity Levels Of Managers And Staff In The Public Sector, Patrick Eduardo O'Mara
LSU Master's Theses
Extensive research has shown the impact of Lean implementation at the process level of an organization to increase quality, reduce cycle time, and reduce operational costs. However, little research has been done to associate Lean with improvement at the strategic level of an organization. The objectives of the present research were to (a) study the association of Lean implementation with maturity levels of employees (b) study the relationship between Lean implementation in the levels of agreement with cohesion between managers and staff in evaluating perceived current state and desired state of organizational practices (c) identify potential barriers of Lean implementation …
Using Eye-Tracking To Investigate Strategy And Performance Of Expert And Novice Control Room Operators, Christina Marie Koffskey
Using Eye-Tracking To Investigate Strategy And Performance Of Expert And Novice Control Room Operators, Christina Marie Koffskey
LSU Master's Theses
There is lacking research within the Petrochemical Industry that uses eye-tracking to explore the differences between the strategies of expert and novice control room operators as they monitor and address process parameters that could be used to improve novice training programs and interface design. Scan paths and three eye-tracking metrics (Fixation Frequency, Gaze Duration Mean, and Gaze Percentage) were used to investigate the differences in eye behavior of three expert control room operators and six novice students as they monitored and corrected a Crude Refinement simulation. A 2x2x2 mixed factor design was used to explore the effects that expertise (expert …