Mechanical Engineering Commons^™

Analyses For Assessing The Centreline Translation, Asymmetrical Wind-Field, And Velocity Fluctuations Of Tornado Vortices, Niall C. Bannigan

Electronic Thesis and Dissertation Repository

Tornadoes present an ever-increasing threat to communities worldwide, especially those with geographic conditions that place them in the path of several tornadoes annually. These conditions are likely to be exacerbated by ongoing trends in the climate. As such, it is necessary to move towards experimental and numerical tornado-like vortex studies that allow for more advanced simulation methods. Novel techniques for tracking and analysing tornado vortices simulated at high spatial and temporal resolution are presented herein. Significant wandering of the tornado's position and large peaks in the velocity field can be captured, demonstrating tangential gusting at more than 1.5 times the …

Study Of Multi-Dimensional Transfer Effects In Applied Smouldering Systems, Seyed Ziaedin Miry Mr

Electronic Thesis and Dissertation Repository

Smouldering is a flameless form of combustion that is driven by oxygen directly diffusing into the surface of condensed phase fuel (liquid or solid) and involves a complex interplay between heat and mass transfer through porous media, chemical reactions, and multiphase flow. Applied smouldering systems have been gaining popularity for a variety of applications including (i) energy and resource recovery, (ii) waste-to-energy, (iii) pyrolysis and gasification, and (iv) applied smouldering of organic liquids/solids for environmental benefits. In all contexts, smouldering is a complicated oxygen-limited phenomenon where multi-dimensional transfer effects (i.e., non-uniformities in …

Onshore Power For The Docked Container Vessels In Apapa Port Through Blended Finance, Oladayo Matthew Atilola

World Maritime University Dissertations

No abstract provided.

Potential Roles Of Vessel Traffic Services (Vts) In Maritime Decarbonization, Suleiman Mustapha Bunza

World Maritime University Dissertations

No abstract provided.

Aeroponic System Optimization For Butterhead Lettuce Growth And Future Sustainability Using Flow Blurring Atomization, Taylor J. Johnson

Doctoral Dissertations and Master's Theses

The global population has grown by 6 billion people over the last century and is trending toward 9.7 billion people by the year 2050. Agriculture accounts for 70% of global fresh water usage. Technology must be developed to accommodate the increase of food production demanded by the growing global population and the subsequent increase in water usage. Aeroponic technology is a water-efficient vertical farming technology that can reduce water usage by 90% by suspending plant roots in air within a controlled chamber and supplying atomized droplets of a water-nutrient solution directly to the roots.

This study simultaneously tests six droplet …

Developing And Testing Low-Cost Air Cleaners For Safer Spaces During Wildfires, Brett William Stinson

Dissertations and Theses

Air cleaning reduces indoor exposure to fine particulate matter (PM_2.5) during wildfire events. However, resource and cost restraints may limit access to air cleaning during such an event, as both commercial devices and the high-rated MERV filters that homemade assemblies typically rely upon tend to be expensive and in short supply. With these barriers in mind, we sought to develop and evaluate the potential for air cleaners that use common household fabrics as filtration media. Evaluated designs use a box fan to move air across fabric filters; box fans are inexpensive and readily available to many households. Ultimately, …

Rattus Norvegicus As A Biological Detector Of Clandestine Remains And The Use Of Ultrasonic Vocalizations As A Locating Mechanism, Gabrielle M. Johnston

Master's Theses

In investigations, locating missing persons and clandestine remains are imperative. One way that first responder and police agencies can search for the remains is by using cadaver dogs as biological detectors. Cadaver dogs are typically used due to their olfactory sensitivity and ability to detect low concentrations of volatile organic compounds produced by biological remains. Cadaver dogs are typically chosen for their stamina, agility, and olfactory sensitivity. However, what is not taken into account often is the size of the animal and the expense of maintaining and training the animal. Cadaver dogs are typically large breeds that cannot fit in …

Trace Dna Detection Using Diamond Dye: A Recovery Technique To Yield More Dna, Leah Davis

Master's Theses

This study aspires to find a new screening approach to trace DNA recovery techniques to yield a higher quantity of trace DNA from larger items of evidence. It takes the path of visualizing trace DNA on items of evidence with potential DNA so analysts can swab a more localized area rather than attempting to recover trace DNA through the general swabbing technique currently used for trace DNA recovery. The first and second parts consisted of observing trace DNA interaction with Diamond Dye on porous and non-porous surfaces.

The third part involved applying the Diamond Dye solution by spraying it onto …

A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize …

Estimating Solar Energy Production In Urban Areas For Electric Vehicles, Shaimaa Ahmed

Theses and Dissertations

Cities have a high potential for solar energy from PVs installed on buildings' rooftops. There is an increased demand for solar energy in cities to reduce the negative effect of climate change. The thesis investigates solar energy potential in urban areas. It tries to determine how to detect and identify available rooftop areas, how to calculate suitable ones after excluding the effects of the shade, and the estimated energy generated from PVs. Geographic Information Sciences (GIS) and Remote Sensing (RS) are used in solar city planning. The goal of this research is to assess available and suitable rooftops areas using …

Environmental Design And Optimization Of Modular Hydropower Plants, Colin Sasthav

Doctoral Dissertations

This research aimed to understand the pathways to cost-effective and sustainable low-head hydropower. Designing viable hydropower projects requires optimization across many economic, environmental, and social outcomes. However, existing run-of-river hydropower design models often focus on economic performance and customizing technologies for high-head diversion schemes. Standard modular hydropower is a new design approach that uses standardized rather than custom-designed technologies to achieve economies of scale. Oak Ridge National Laboratory established a conceptual outline for module classes based on functions, such as generation modules and fish passage modules, but further research was needed to identify how modules should be selected and operated …

Identification Of Phosphorous Loading Point Source Facilities To 303(D) Listed Nutrient Impaired Waters Through Watershed Delineation Using Arcgis For Life Cycle Assessment Applications, John Zimmerman

Chemical Engineering Undergraduate Honors Theses

The work done for this project is part of a larger “life cycle assessment (LCA) of novel electrochemical phosphorus recovery technology at the wastewater treatment plant and U.S. watershed scales” (Morrissey 2019). The goal of that LCA is to determine “environmental impacts of implementing electrochemical struvite recovery at the wastewater treatment plant, U.S watershed, and global scales” (Morrissey 2019). This project’s goal is to identify locations deemed more sensitive to eutrophication impacts. The results will be used as part of the life cycle inventory (LCI) accounting for geographically explicit phosphorus flows. The waters identified as impaired were sourced from the …

Experimental Simulation Of Tornado-Like Vortices And Their Impact On High-Rise Buildings, Arash Ashrafi

Electronic Thesis and Dissertation Repository

One of the most crucial research areas in wind engineering is tornadoes due to the widespread damages to infrastructure and the environment in North America and other parts of the world. The proper scaling of tornadoes in experimental facilities, generating tornado-like vortices (TLVs) is, therefore, an essential part of evaluating tornado-indued damages on engineered buildings. The capability of producing TLVs of length scales in the range between 1:300 and 1:150 inside the Wind Engineering, Energy and Environment (WindEEE) Dome at Western University has already been demonstrated using only one mode of the full potential of this simulator. A new mode …

Desalination For Sustainable Water Production With An Emphasis On Low Pressure Distillation, Jessica Vivian Savage

Doctoral Dissertations and Master's Theses

Freshwater resources depletion is a growing concern. This freshwater scarcity motivates research into seawater desalination as a means for alleviating the stresses on water demands. The primary methods of desalination include filtration and distillation. This paper explores the potential energy savings of vacuum distillation for seawater desalination to reduce the amount of energy needed to achieve phase change.

Depending on the vacuum boiler design, the vaporization mechanism may be boiling, evaporation, or cavitation. There is very little literature on cavitation that involves mass transfer, so cavitation is not developed here. This thesis focuses on standard models for boiling and evaporation …

Integrated Modelling Of Wastewater Treatment And Sewer Processes - Interactions Of Fluid Flow, Mass Transfer, And Biochemical Reactions, Ahmed Khalil

Electronic Thesis and Dissertation Repository

Numerical modelling of wastewater management systems is crucial for investigating alternative designs and developing strategies for operation and control that improve the performance of the treatment stage (such as improving the aeration systems in activated sludge systems). Modelling can also help operators to mitigate common problems that arise from unwanted biochemical conversions in the sewer networks (such as the production of sulfide and methane). Therefore, this work focuses on two major areas related to modelling wastewater management systems. First, it seeks to develop more accurate models for aeration systems in activated sludge reactors. Second, it seeks to study the mathematical …

Nze Residential Test Facility Analysis Throughout Summer/Winter Peak Months For Thermal Comfort Prediction, Yearim Yang

Honors College Theses

The present study evaluates the thermal comfort in the east bedroom of the Net-Zero Energy Residential Test Facility (NZERTF) in a mixed-humid climate. This unit was constructed by the National Institute of Standards and Technology for scholars to analyze its energy performance and indoor environmental quality. The thermal comfort is investigated in a designated bedroom space by analyzing 27 dry-bulb temperature, 4 airspeed, 6 globe temperature, and 6 relative humidity sensors in a 3x3x3 array and a center sensor stand during two opposite seasonal months (July and December). The conventionally ducted heat pump, small duct high velocity, and heat recovery …

Numerical And Experimental Investigation Of Aeration Self Mixing By Using Pulsating And Continuous Air Flow, Ahmed Ali Alkhafaji

Theses and Dissertations

Wastewater treatment is considered one of the most common forms of pollution control in the united states. Considered as an integral part of the wastewater treatment, the aeration process is the most energy-consuming process among all the processes that take place in any wastewater treatment plant. According to the United States Environmental Protection Agency (EPA), a wastewater treatment plant is expected to remove at least 85% of the suspended solids and dissolved organic compounds from the wastewater before discharging it to a river or a lake. The normal operation of the aeration process is by compressing air continuously to basin …

Detailed Modeling Of The Flash Hydrolysis Of Algae For Biofuel-Production In Comsol Multiphysics, Noah Joseph Legrand

Mechanical & Aerospace Engineering Theses & Dissertations

Algae-derived biofuels are being commercialized as an important renewable energy source. Like any new technology, conversion improvements are desired, including reductions in process complexity and better utilization of the entire microalgae feedstock. The Old Dominion Biomass Laboratory has focused on flash hydrolysis for algae biofuel production. That process involves rapidly heating algae and water mixed as a slurry to a subcritical state. Results from small-scale bench tests are promising, but process scale up is a challenge. Currently there exists a pilot laboratory scale system utilizing induction heating in order to reach controlled reaction temperatures with a reaction duration of 10 …

Sustainable Smouldering For Waste-To-Energy: Scale, Heat Losses, And Energy Efficiency, Tarek L. Rashwan

Electronic Thesis and Dissertation Repository

Applied smouldering combustion is emerging as a highly energy efficient approach towards waste-to-energy. This thesis aims to better understand this potential by addressing a critical knowledge gap between laboratory scale smouldering research and large-scale applications. Altogether, new understanding in provided on the complex and dynamic interactions between the reaction zone (smouldering front) and the cooling zone (treated inert porous media) by integrating theory, experiments, analytical modelling, and global energy balance calculations. The experiments spanned a range of reactor sizes and smouldering conditions (from weak to robust) with dry (carbon) and wet (sludge) fuels mixed in sand. This work revealed that …

Wave Attenuation Capacity Of Suspended Aquaculture Structures With Sugar Kelp And Mussels, Longhuan Zhu

Electronic Theses and Dissertations

Large aquaculture systems may have the potential to damp wave energy for coastal protection. The performance of these systems are influenced by the dynamics of components such as flexible kelp blades and mussel droppers. In this thesis, the dynamics of kelp blades and mussel droppers were investigated with a consistent-mass cable model with focus on understanding the asymmetric motion of kelp blades. The results showed the asymmetric blade motion in symmetric waves is caused by the spatial asymmetry of the encountered wave orbital velocities due to blade displacements and the asymmetric action on the blade by vertical wave orbital velocities. …

Modeling Of Electrical Grid Systems To Evaluate Sustainable Electricity Generation In Pakistan, Muhammad Mustafa Amjad

Masters Theses

Pakistan has always had a history of severe energy shortfalls, which rose up to an alarming 33% in 2013. This situation was countered by investments in the energy sector through the China Pakistan Economic Corridor (CPEC), which were unfortunately largely based on brown fuels. Although beneficial in the short term, these investments do not bode well for the climate scenario of Pakistan, with various parts of the country already having experienced temperatures rise of 1-3°C. To ensure that the current situation doesn’t exacerbate and is tackled in a timely manner, this research aims to examine how the untapped potential of …

Compound Flooding In Coastal Areas Emanating From Inland And Offshore Events, Hamed Behzad Koochaksaraii

Dissertations

The vulnerability of urban populations to natural hazards and climate change is a major theme in many reports on coastal cities with flooding ranking highly among the climate change concerns. Flooding could occur as a result of runoff for inland rainfall that accumulates at the mouth of the estuary to the sea or it could occur due to a storm surge emanating from the ocean. The techniques for modeling the flooding from these events are very different, as they were developed in different scientific fields: hydrology and hydraulic engineering for inland rainfall versus coastal oceanography and coastal engineering for offshore …

Adapting To Extreme Heat: Social, Atmospheric, And Infrastructure Impacts Of Air Conditioning In Megacities - The Case Of New York City, Harold Gamarro

Dissertations and Theses

Extreme heat events are becoming more frequent and intense in most large cities. Built-up surfaces also limit cooling mechanisms, leading to warmer conditions in cities, a phenomenon called the Urban Heat Island (UHI). This presents major challenges to reduce adverse health effects of hot weather, particularly in vulnerable populations like the elderly and low-income communities. Here we explore the overall impacts of increasing air conditioning (AC) system adoption in residences as an adaptive measure to reduce human health risks under heat waves, with New York City (NYC) as a case study. This study uses AC adoption data from the 2017 …

Electrification Of Domestic Hot Water To Aid The Integration Of Renewable Energy In The California Grid, Alejandro Cervantes

Cal Poly Humboldt theses and projects

Water heating in residential buildings, also known as domestic hot water (DHW), is the third largest use of energy after appliances and space conditioning. About 90% of the residential buildings in the state use natural gas fueled water heaters, 6% use electricity, and a small percent use liquefied petroleum gas (LPG) or solar water heaters. The current energy use associated with residential water heating is small relative to the total amount of energy consumption in the residential building sector, but it is still a contributor of greenhouse gas (GHG) emissions. Improving hot water systems can be beneficial for bill customer …

Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Granular activated carbon (AC) and biochar (BC) are two carbon-based adsorbents commonly used for water and wastewater treatment. However, these adsorbents have drawbacks that suppress their aqueous contaminants removal efficiency. Their major disadvantages are that AC has low selectivity and reusability potential, and BC has a hydrophobic nature.

The scope of this dissertation is to enhance the performance of commonly-used carbon-based adsorbents for the removal of organic and inorganic water contaminants and to understand the interactive mechanism of contaminants’ ions/molecules with adsorbents. Hexavalent chromium (Cr(VI)) and trichloroethylene (TCE) are two types of inorganic and organic water contaminants, respectively, which are …

Model Block Press Design, Ben Todd Van Hamersveld, Chester Wong, Alexander Wing-Jon Giannousis

Mechanical Engineering

This project’s goal is to redesign the Center for Vocational Building Technology (CVBT) BP9 earth block press, which makes 1/3 scale compressed earth blocks to build demonstration model homes in Thailand. The full-scale block press, the BP6, provides a sustainable and affordable technique for constructing habitable homes in Thailand. The BP9 serves as a tool to inform the public of the advantages of human-powered earth block presses through demonstration. The BP9 press design has multiple problems: it is too expensive to manufacture, there is too much friction when used, it has several weak points due to users unintentionally applying excessive …

Effects On Strength And Corrosive Characteristics Of Hardened Cement Paste Using Rice Husk And Sugarcane Bagasse, Travis D. Garrett

Master's Theses

Cement is one of the most used building materials in the world. The production of ordinary Portland cement contributes to the release of harmful greenhouse gasses. In an effort to reduce these emissions, different materials are being evaluated for their use as partial replacements for ordinary Portland cement. Rice husk and sugarcane bagasse are agricultural waste products and large amounts of these are currently landfilled, making them inexpensive and available. When combusted at high temperatures they form rice husk ash and sugarcane bagasse ash that have pozzolanic characteristics. The high silicon dioxide in these products makes them good options to …

Numerical Simulation For The Hydrodynamic Performance Of Hydropower Turbine Near Free Surface, Zeda Yin

Theses, Dissertations and Capstones

The performance of hydropower turbine in shallow water can be affected by the presence of free surface. Therefore, it is of great interest to investigate the influence of free surface on hydropower turbine performance through computational simulations. For a better understanding of flow field around hydropower turbine operating in shallow water, it is important to analyze the flow over a single hydrofoil beneath free surface first. Therefore, as the first part of this thesis, the Computational Fluid Dynamics (CFD) methodology was used for numerical simulation of 2D unsteady incompressible viscous flow over a hydrofoil under the free surface. The computation …

Experimental And Numerical Characterization Of Multiphase Subsurface Oil Release, Feng Gao

Dissertations

Subsurface oil release is commonly encountered in the natural environment and engineering applications and has received the substantial attention of researchers after the disastrous Deepwater Horizon Blowout oil spill in 2009. The main focus on the present research is to systematically study the hydrodynamics of underwater oil jet under a variety of conditions, including the effect of dispersant and different gas to oil ratios (GOR) by using experimental measurement as well as a Computational Fluid Dynamics (CFD) approach, from which the measured turbulent characteristics (e.g., velocity, turbulent kinetic energy, turbulence dissipation rate, etc.) of underwater oil jet are thoroughly examined …

Towards Environmentally Sustainable And Cost-Effective Food Distribution In The U.S., Jasmina Burek

Graduate Theses and Dissertations

Distribution centers (DCs) and supermarkets have an important role in food sustainability, but no previous research has accounted for their environmental impact. The purpose of this research was to assess environmental sustainability of grocery, perishables, and general merchandise DCs; to estimate food storing and retailing impact; and to provide cost-effective strategies to reduce DCs’ environmental impacts. The importance and relevance of the research is threefold: improving sustainability of DCs, food storing, and food retailing. The main method used in this research was the life cycle assessment (LCA) method. An initial study calculated environmental impacts of the Wal-Mart Stores, Inc. DCs, …