Mechanical Engineering Commons^™

Scaling Cellular Agriculture Production With Photolithography: A Study On Curing And Degradation, Alexis Garrett

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

To meet the requirements for full production in cellular agriculture, a multi-disciplinary approach is required. New questions and understandings between different concepts, such as texture and cooking, need to be identified and how they correlate with cellular behavior and taste. This work focuses on understanding and developing photolithographic systems for scalable cellular agriculture. There were two specific research directions: 1) a traditional photolithography printing system was improved upon for mass manufacturing purposes and 2) mechanical analysis and degradation of key potential photolithographic biomaterials were tested for a food product. A novel digital rotational ultraviolet manufacturing (DRUM) process was developed, and …

Evaluation Of Accelerated Testing Methods To Predict The Effects Of Chemical Exposure On Mechanical Properties Of Polyester Composites In Municipal Wastewater Service, Roberto A. Garcia

Theses and Dissertations

Composite Access Products (CAP) is a company that is determined to replace traditional steel manhole covers with fiber reinforced polymer alternatives that have similar performance while also introducing several advantages. CAP can achieve this by manufacturing the polymer manhole covers using high-speed, high pressure compressing molding to produce lightweight, long-lasting, corrosive resistant covers. CAP’s composite covers have been approved for use by TXDOT in roadway zones. Despite this, they must now undergo more testing and verification for use in environments with highly corrosive elements such as sewage environments and waste processing plants. In these situations, the polymer manhole covers will …

Performance Loss Rate And Temperature Modeling In Predictive Energy Yield Programs For Utility-Scale Solar Power Plants, Katelynn M. Dinius

Master's Theses

The Gold Tree Solar Farm, designed by REC Solar, has a rated output power of 4.5 MW and began operation in 2018 to provide electricity to Cal Poly’s campus. Gold Tree Solar Farm site terrain consists of rolling hills and uneven slopes. The uneven typography results in interrow shading, requiring a modified tracking control algorithm to maximize power production. Predicting a utility solar field’s lifetime energy yield is a critical step in assessing project feasibility and calculating project revenue. The MATLAB-based predictive power model developed for this field overpredicted power in the middle of the day. The purpose of this …

Laser Micropatterning Effects On Corrosion Resistance Of Pure Magnesium Surfaces, Yahya Efe Yayoglu

USF Tampa Graduate Theses and Dissertations

Magnesium and its alloys are good candidates to manufacture medical implants. They have excellent biocompatibility and because they biodegrade secondary surgical operation to remove the implant could be eliminated. However, in aqueous environments, magnesium alloys rapidly corrode, resulting in premature degradation of the implant along with biologically intolerable hydrogen gas generation. In literature, there are multiple studies focused on creating water repelling hydrophobic magnesium surfaces in order to decrease corrosion rates. Hydrophobic properties can be achieved by creation of a roughness profile on an initially smooth surface combined with a treatment that reduces the free surface energy. In theory, hydrophobic …

Wetting Metamorphosis Of Hydrophobic Fluoropolymer Coatings Submerged In Water And Ultrasonically Vibrated, Matthew Trapuzzano, Nathan B. Crane, Rasim Guldiken, Andrés Tejada-Martínez

Faculty Publications

Many important processes, from manufacture of integrated circuit boards, to an insect’s ability to walk on water, depend on the wetting of liquids on surfaces. Wetting is commonly controlled through material selection, coatings, and/or surface texture. However, wetting is sensitive to environmental conditions. In particular, some hydrophobic fluoropolymer coatings are sensitive to extended water exposure as evidenced by a declining contact angle and increasing contact angle hysteresis. Understanding “degradation” of these coatings is critical to applications that employ them. The durability of a series of fluoropolymer coatings were tested by measuring the contact angle before, during, and after extended submersion …

Dynamic Response Modeling Of High Speed Planing Craft With Enforced Acceleration, Brian K. Johnson

Mechanical & Aerospace Engineering Theses & Dissertations

Due to the harsh conditions high speed planing crafts must endure, research to further the understanding of high speed vessel response during wave impacts was conducted. The integration of a finite element model and captured sea trial acceleration data was investigated. The research shows that the finite element model sub-model can be used in lieu of a full finite element model with minimum degradation in output, thus allowing for the analysis of local stress concentrations where critical equipment and or personnel may be located.

The research effort was completed to develop a method for realizing the stress field and deformation …

Impedance-Resolved Performance And Durability In Redox Flow Batteries, Alan Michael Pezeshki

Doctoral Dissertations

The realization of redox flow batteries (RFBs) as a grid-scale energy solution depends on improving the performance and lifetime of the technology to decrease the high capital costs. The electrodes are a key component in the RFB; performance enhancement is often achieved through chemical or thermal treatments of commercially available porous carbon materials.

This dissertation uses impedance spectroscopy-based methods to gain insight into performance and durability in RFBs, enabling intelligent cell design. Initial work focused on understanding the impact of improved electrode and membrane properties on system performance. An accelerated stress test was then developed that can be used to …

A Study Of The Mechanical Behavior Of Composite Materials Exposed To Corrosive Environments, Ryan Keith Hedgepeth

Electronic Theses and Dissertations

A collaborative study was conducted to examine the degradation of commercially pultruded uni-directional e-glass composites. The case study specimens, including a variety of commercially pultruded polyester/e-glass and vinylester/e-glass composites were exposed to corrosive environments, namely: distilled water (h2o), bleach (naclo), and hydrochloric acid (hcl) for a minimum of 60 days, and the degradation was analyzed. Such a study was chosen on two accounts, 1) to contribute viable data to industry and research and 2) to provide data to be used to develop a standardized practice to characterize the durability for pultruded composites used for structural applications. A control group was …

On The Degradation Of Lubricating Grease, Asghar Rezasoltani

LSU Doctoral Dissertations

A comprehensive literature review on physical and chemical degradation monitoring and life estimation models for lubricating greases is presented in chapter one. Degradation mechanisms for lubricating grease are categorized and described, and an extensive survey of the available empirical and analytical grease life estimation models including degradation monitoring standards and methods are presented. In chapter two, irreversible thermodynamic theory is employed to study the mechanical degradation of lubricating grease. A correlation between the mechanical degradation and entropy generation is established and the results are verified experimentally using a rheometer, a journal bearing test rig, and a modified grease worker machine. …

Stabilizing Nanostructured Solid Oxide Fuel Cell Cathode With Atomic Layer Deposition, Yunhui Gong, Diego Palacio, Xueyan Song, Rajankumar Patel, Xinhua Liang, Xuan Zhao, John Goodenough, Kevin Huang

Kevin Huang

No abstract provided.

Impact Of In Situ Physical And Chemical Cleaning On Pvdf Membrane Properties And Performances

Faculty of Engineering University of Malaya

Appropriate selection of cleaning agent is an important factor to achieve a better cleaning efficiency and this topic has become an ongoing discussion. This work assesses the impacts of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) aqueous solution towards polyvinylidene fluoride (PVDF) stability at the typical concentrations used in membrane cleaning. The cleaned membranes were characterised using held emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), pure water flux measurement, contact angle, protein retention and tensile testing. Membrane cleaned at elevated temperature and higher concentration presented a higher water flux than the virgin membrane which can be a worrying …

Impact Of In Situ Physical And Chemical Cleaning On Pvdf Membrane Properties And Performances

Faculty of Engineering University of Malaya

Appropriate selection of cleaning agent is an important factor to achieve a better cleaning efficiency and this topic has become an ongoing discussion. This work assesses the impacts of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) aqueous solution towards polyvinylidene fluoride (PVDF) stability at the typical concentrations used in membrane cleaning. The cleaned membranes were characterised using held emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), pure water flux measurement, contact angle, protein retention and tensile testing. Membrane cleaned at elevated temperature and higher concentration presented a higher water flux than the virgin membrane which can be a worrying …

Degradation And Fatigue Involving Dissipated Processes, Md Liakat Ali

LSU Doctoral Dissertations

Irreversible material degradation due to cyclic mechanical loading is investigated utilizing the concept of thermodynamic entropy, plastic strain energy, and temperature slope measurement. Uniaxial tension-compression and fully-reversed bending fatigue tests are performed over a wide range of loading conditions with metallic and composite materials subject to both constant- and variable-amplitude loading. A methodology is developed for the estimation of the fatigue fracture entropy (FFE) and fatigue toughness of metallic specimens in a rapid fashion. It is found that the FFE and the fatigue toughness of each material tested are within a small band. The value of FFE is found to …

The Role Of Channel-Land Architecture, Diffusion Media Transport Properties, And Aging Effects On Water Transport And Storage In Polymer Electrolyte Fuel Cells, Jacob Michael Lamanna

Doctoral Dissertations

Thermally driven transport of water vapor in polymer electrolyte fuel cells, also known as the heat-pipe effect or phase-change-induced flow, can transport several times the generated amount of water given enough temperature differentials. Understanding this transport process is necessary to properly engineer the water balance in the fuel cell to ensure high performance and long operational life. Channel-land architecture, diffusion media heat and mass transport properties, and operational age can all have an influence on thermally driven flow. High resolution neutron imaging was used to determine the steady-state water accumulation in various cell configurations to understand the influence of these …

Modeling Of Chemical-Mechanical Couplings In Solid Oxide Cells And Reliability Analysis, Xinfang Jin

Theses and Dissertations

Solid oxide fuel cell (SOFC) has been well demonstrated as a promising clean energy conversion technology. For practical applications, the SOFC systems should have both good electrochemical performance and high reliability. The SOFCs are usually operated under very aggressive conditions, e.g., high temperatures (600-1000oC) and extremely low oxygen partial pressures (anode electrode). These aggressive operating conditions could lead to a variety of material system degradations, imposing great challenges on meeting lifetime requirement of SOFC commercial applications. It is therefore essential to increase the understanding of fundamental SOFC degradation mechanisms.

The basic structure of SOFCs is a positive electrode-electrolyte-negative electrode (PEN) …

Material Characterization And The Effects Of Moisture And Drying On Injection Molded Torlon 5030, Michael R. Di Re

Master's Theses

The effects of water absorption and drying were studied on injection molded Torlon 5030, a high performance thermoplastic fabricated by Solvay Specialty Polymers. Torlon 5030 contains 30% by weight glass fibers in a polyamide-imide base resin. The objective behind this work was to test and better define relevant properties for industrial applications using this material. While the material design guide offers information on many mechanical properties including tensile, fatigue, and creep data; there is little to no publicly published data on the effects of water absorption and any subsequent drying of Torlon 5030. Blistering was also studied. With exposure to …

A Hybrid Constitutive Model For Creep, Fatigue, And Creep-Fatigue Damage, Calvin Stewart

Electronic Theses and Dissertations

In the combustion zone of industrial- and aero- gas turbines, thermomechanical fatigue (TMF) is the dominant damage mechanism. Thermomechanical fatigue is a coupling of independent creep, fatigue, and oxidation damage mechanisms that interact and accelerate microstructural degradation. A mixture of intergranular cracking due to creep, transgranular cracking due to fatigue, and surface embrittlement due to oxidation is often observed in gas turbine components removed from service. The current maintenance scheme for gas turbines is to remove components from service when any criteria (elongation, stress-rupture, crack length, etc.) exceed the designed maximum allowable. Experimental, theoretical, and numerical analyses are performed to …

Degradation Of Automotive Materials In Palm Biodiesel

A.S. Md Abdul Haseeb

As compared to petroleum diesel, biodiesel is more corrosive for automotive materials. Studies on the characterization of corrosion products of fuel exposed automotive materials are scarce. Automotive fuel system and engine components are made from different ferrous and non-ferrous materials. The present study aims to investigate the corrosion products of different types of automotive materials such as copper, brass, aluminum and cast iron upon exposure to diesel and palm biodiesel. Changes in fuel properties due to exposure of different materials were also examined. Degradation of metal surface was characterized by digital camera, SEM/EDS and X-ray diffraction (XRD). Fuel properties were …

Nanotopographic Cell Culture Substrate: Polymer-Demixed Nanotextured Films Under Cell Culture Conditions, Jung Yul Lim, Christopher A. Siedlecki, Henry J. Donahue

Department of Mechanical and Materials Engineering: Faculty Publications

Modulating physical cell culture environments via nanoscale substrate topographic modification has recently been of significant interest in regenerative medicine. Many studies have utilized a polymer-demixing technique to produce nanotextured films and showed that cellular adhesion, proliferation, and differentiation could be regulated by the shape and scale of the polymer-demixed nanotopographies. However, little attention has been paid to the topographic fidelity of the polymer-demixed films when exposed to cell culture conditions. In this brief article, two polymer-demixing systems were employed to assess topographic changes in polymer-demixed films after fibronectin (FN) extracellular matrix protein adsorption and after incubation in phosphate-buffered saline at …

Degradation Of Physical Properties Of Different Elastomers Upon Exposure To Palm Biodiesel

A.S. Md Abdul Haseeb

Biodiesel, as an alternative fuel, is gradually receiving more popularity for use in internal combustion engines. However questions continue to arise with regard to its compatibility with elastomeric materials. The present work aims to investigate the comparative degradation of physical properties for different elastomers [e.g. ethylene propylene diene monomer (EPDM), silicone rubber (SR), polychloroprene (CR), polytetrafluroethylene (PTFE) and nitrile rubber (NBR)] upon exposure to diesel and palm biodiesel. Static immersion tests in B0(diesel), B10 (10% biodiesel in diesel), B20, B50 and B100(biodiesel) were carried out at room temperature (25 °C) for 1000 h. Different physical properties like, changes in weight …

Failure Analysis Of Retrieved Uhmwpe Tibial Insert In Total Knee Replacement

A.S. Md Abdul Haseeb

This study involves the failure analysis of an ultra high molecular polyethylene (UHMWPE) tibial insert from Apollo® Total Knee System, which was removed after 10. years of service from 70. years old female patient. The tibial insert was investigated by using a stereoscope, scanning electron microscope (SEM), infinite focus microscope (IFM) and energy disperse spectroscopy (EDS) to characterize the morphology and composition of the bearing surface. Differential scanning calorimetry (DSC) and Fourier transform spectroscopy (FTIR) were employed to characterize the degradation and crystallinity of the component. Gel-permeation chromatography (GPC) was used to measure the polyethylene tibial insert molecular weight. Results …

Compatibility Of Elastomers In Palm Biodiesel

A.S. Md Abdul Haseeb

In recent time, environmental awareness and concern over the rapid exhaustion of fossil fuels have led to an increased popularity of biodiesel as an alternative fuel for automobiles. However, there are concerns over enhanced degradation of automotive materials in biodiesel. The present study aims to investigate the impact of palm biodiesel on the degradation behavior of elastomers such as nitrile rubber (NBR), polychloroprene, and fluoro-viton A. Static immersion tests in B0 (diesel), B10 (10% biodiesel in diesel), B100 (biodiesel) were carried out at room temperature (25 °C) and at 50 °C for 500 h. At the end of immersion test, …

Petroleum Degradation In Soil By Thermophilic Bacteria With Biopile Reactor, Astri Nugroho, Edison Effendi, Yulius Karonta

Makara Journal of Technology

Crude oil degradation has been carried out using biopile reactor in total petroleum hydrocarbon (TPH) concentration of 5%, 10% and 15%. The thermophilic microorganisms used from isolation result and identification are Aeromonas salmonicida, Bacillus pantothenticus, and Stenotrophomonas maltophilia. The biodegradation of biopile reactor is done by various concentrations of TPH, total plate count (TPC), and volatile suspended solid (VSS) per day for 30 days. The biodegradation of kinetic parameter calculated consists of μ, μm, Y, Yt, Yobs, Kd, Ks from TPH concentration decision, and TPC and VSS in every microorganism with t (observation time) of 0 hour to 168 hours. …

Crude Oil Sludge Degradation In Microcosmic Scale: Simple Simulation As Preliminary Study On Land Treatment Bioremediation., Astri Nugroho

Makara Journal of Technology

Crude Oil Sludge Degradation in Microcosmic Scale: Simple Simulation as Preliminary Study on Land Treatment Bioremediation. A study in microcosmic condition has been carried out to evaluate the bacterial hydrocarbonoclastic capability in increasing the oil sludge degradation being mixed with NPK fertilizer as nitrogen resources. Aerobic test was carried out by putting erlenmeyers in a shaker incubator, 120 rpm shaking speed, at 50°C temperature. While 150 days in microcosmic one observation showed that the consortium has the potential to grow up to 50% (v/v) sludge oil load. Maximum growth and maximum growth rate of the consortium occurred in the III …

Synthesis Dibenzyl Terephthalate Through Depolimerization Of Poly (Ethylene Terephthalate) As Alternative Of Waste Plastics Recycling, Suwardi Suwardi, Crys Fajar Partana, Agus Salim, Dyah Anitasari

Makara Journal of Technology

Synthesis Dibenzyl Terephthalate Through Depolimerization of Poly(ethylene terephthalate) as Alternative of Waste Plastics Recycling. Synthesis dibenzyl terephathalate were done through PET degradation by refluxing in benzyl alcohol at 145oC temperature for 20, 24, and 28 hours in the presence of zinc acetate catalyst. The result of degradation was purified by recristalization in methanol and then melting point (mp), FTIR, 1H NMR spectra, and TLC spot were determined. The melting point of product degradation for 28 hours was 98-99 oC. Based FTIR spectra known that compunds of product degradation have OH, C=O, C-O, CH, monosubstituted benzene, disubstituted benzene groups, while on …

The Development Of An Accelerated Testing Facility For The Study Of Deposits In Land-Based Gas Turbine Engines, Jared Wilfred Jensen

Theses and Dissertations

Turbine engine efficiency modeling depends on many parameters related to fluid dynamics and heat transfer. Many of these parameters change dynamically once the engine enters service and begins to experience surface degradation. This thesis presents a validation of the design and operation of an accelerated testing facility for the study of foreign deposit layers typical to the operation of land-based gas turbines. It also reports on the use of this facility in an effort to characterize the change in thermal resistance on the surface of turbine blades as deposits accumulate. The facility was designed to produce turbine deposits in a …