Mechanical Engineering Commons^™

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 …

Damage Evolution And High-Rate Response Of High-Strength Concrete Under Triaxial Loading, Brett Williams

Mechanical Engineering Research Theses and Dissertations

The research presented in this study focuses on understanding fundamental mechanisms that drive material response under dynamic loading conditions. The objectives of the research were to: (1) to understand damage initiation and propagation in the bulk geomaterial under a variety of loading conditions and (2) to systematically investigate the strain rate effects on the triaxial compressive response of cementitious materials through the development of an innovative, first of its kind large-diameter (50 mm) triaxial Kolsky bar system.

The triaxial compressive response of high-strength concrete is needed to understand pressure-dependent material behavior, which is important for modeling extreme loading events. However, …

Hydraulic Balsa Wood Rising Bridge, Kaitlyn Greenfield

All Undergraduate Projects

What is the solution to allowing tall vessels to navigate past a vehicle bridge that is less than 10 [ft] above the water? To answer this question, a balsa wood bridge was designed, constructed, and tested. The bridge needed to articulate by mechanical means, allow for travel through the bridge, and be able to withstand ample force while the main structure only being constructed of balsa wood and glue. The project was analyzed in sections. These sections include: the bridge structure and its members, the hydraulic lift, and the pins needed for the bridge and hydraulic lift to operate. The …

Balsa Wood Bridge, Andrew Harris

All Undergraduate Projects

Faculty at Central Washington University proposed a challenge to mechanical engineering students that could be accomplished in an in-home setting. The goal was to create a balsa wood bridge, weighing no more than 85 grams, that can support a load over an open span and raise above its resting position by means of a mechanical system. To produce a successful solution to the problem, a vertical lift bridge was created consisting of two lifting towers and a load bearing bridge. Using equations of static equilibrium and strength of materials, the required width for each member was determined. Project requirements were …

Renewable Energy Production By Solar Chimney: The Influence Of Curved Guide Vanes On The Performance Of A Solar Chimney Using Cfd Simulation, Haokun Xue

Theses, Dissertations and Capstones

The aim of this study is to investigate the effect of the guide vanes on the efficiency of the turbine of solar chimney power plant using Computational Fluid Dynamics (CFD). In this study, a 3-Dimentional CFD simulation of solar chimney power plant based on the Manzanares prototype is performed. The CFD simulation is validated by comparing the experimental data from the Manzanares prototype and simulation data with both 2D and 3D cases. To capture turbulent flow inside the chimney, the SST 𝑘 − 𝜔 turbulence model is used. The first object is to investigate the flow performance under the influence …

Localization Of Stationary Source Of Floor Vibration Using The Steered Response Power Method, Mohammad Royvaran

Theses and Dissertations--Civil Engineering

If the generated vibration in a building exceeds the acceptable limit design for a floor system, it is necessary to identify the source of vibration, a process known as localization. The objective of this study is the localization of stationary vibration sources, and the approach used is the steered response power (SRP) method. This method has already been shown to work well for wireless and acoustical applications to locate transmitter and sound sources, respectively. To the writer’s knowledge, this study is the first application of the SRP method to locate vibration sources using floor vibration measurements. However, because waves behave …

Econometric Frameworks For Energy Prediction, Naveen Chandra Iraganaboina

Electronic Theses and Dissertations, 2020-

Global warming and associated role of energy consumption across various sectors is a well-researched topic in recent years. Understanding current urban energy consumption patterns will allow us to understand how future energy consumption patterns will evolve. With electrification of vehicles and potentially altering culture of work from home, the energy usage at regional level would see a significant change in the future. The current PhD dissertation contributes to energy consumption analysis of a region by analyzing residential energy consumption, commercial energy consumption and transportation energy use by households. The aggregation of these energy consumption within a region contributes to the …

Macrotexture Assessment Of Florida Pavements, Alexander C. Oracheff

UNF Graduate Theses and Dissertations

When water has nowhere to escape from the surface of a roadway, it can disrupt the tire-to-pavement adhesion of a traveling vehicle and lead to hydroplaning. Pavement macrotexture provides the pathways for water to drain, which allows for the necessary grip between tire and pavement. Macrotexture, which is quantified by the Florida Department of Transportation (FDOT) in terms of mean profile depth (MPD), is analyzed by the State Materials Office using a high-speed point-laser mounted along the driver side wheel path of a friction testing vehicle.

While point-lasers are capable of accurately measuring MPD on flexible pavement, the system fails …

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 …

The Optimization Of Efficiency And Infrastructure For Modern Potable Water Treatment Plants, Brent A. Dekock

Theses and Dissertations

The USDOE Industrial Assessment Centers (IACs) is a program that is designed to help small and medium-sized manufacturing facilities reduce their overall costs and improve energy efficiency. This includes improving potable water treatment plants which supply water throughout the country. This thesis covers the process of how IAC branches and water treatment facilities generally operate, as well as several assessment recommendations that have been developed by a branch of the IAC for several water treatment plants based in the Rio Grande Valley of Texas. The steps of the assessment and water treatment process are described, and several cost saving measures …

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 …

Analysis Of Burning Wood In The Transient State And The Application To Structural Design, Roberta Veliz, Kimberly Guzman

Architectural Engineering

Determining the extent of the contribution of exposed timber on compartment fire dynamics in open floor plans is a complex process. Designers traditionally used compartmentalization design methods which create spaces where flashover is likely, given the fuel load and ventilation conditions. However, due to the large geometric dimensions and spread of fuel, fires in open floor plans are more likely to remain as localized or traveling fires. As such, an understanding of not only ignition potential but also flame spread is critical to characterizing the contribution of exposed timber. An integral step in characterizing the potential contribution is through an …

Design Of Structural Stand For High-Precision Optics Microscopy, Sara T. Novell

Master's Theses

Lawrence Livermore National Lab (LLNL) is home to the National Ignition Facility (NIF), the world’s largest and most energetic laser. Each of the 192 beamlines contains dozens of large optics, which require offline damage inspection using large, raster-scanning microscopes. The primary microscope used to measure and characterize the optical damage sites has a precision level of 1 µm. Mounted in a class 100 clean room with a raised tile floor, the microscope is supported by a steel stand that structurally connects the microscope to the concrete ground. Due to ambient vibrations experienced in the system, the microscope is only able …

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 …

Design Of A Greywater-Fed Hydroponics System, Alex Estrada, Katya Fairchok, Andrew Feldmeth, Andrew Jezak

Interdisciplinary Design Senior Theses

To combat issues of local water insecurity, a hydroponics system was designed in partnership with LEAP 5 High School in Jane Furse, South Africa. Climate change, increasing human population, and continued environmental degradation all threaten access to clean drinking water. Approximately seventy percent of all freshwater is used for agriculture globally, thus threatening food security especially in developing countries where access to water is potentially volatile. The hydroponics garden system utilizes sustainable materials, a self-monitoring temperature controls system, and greywater input, to act as an educational tool for students and significantly reduce freshwater use compared to traditional, in-ground agriculture. An …

Parklets San Luis, Owen Kenny, Preston Jag Stebel, Leonidas Goodman, Lukas Braun

Industrial and Manufacturing Engineering

Downtown San Luis Obispo has been a popular destination for tourists, students, families, and roadtrippers. However, according to Ryan Betz, Interim Assistant to the City Manager, foot traffic and retail business revenue has been decreasing. Downtown SLO does not have enough free public spaces. Recent projects such as sidewalk bump outs and lighted crosswalks have aimed at making SLO more pedestrian accessible, but they have not actually made downtown more pleasurable. These projects have not seemed to drive any more business or traffic downtown. There are a myriad of ways to rectify this; studies show that having a free place …

Hydronic Service Valve Product Development, Mark Hunsaker

Construction Management

Since the inception of modern mechanical and HVAC systems, maintenance and repairs have been prevalent in both contracting and facility operations. The average life of HVAC equipment is fractional compared to the life of buildings as construction technologies improve. Traditionally, the serviceability of heating and cooling equipment has entailed the significant amounts of labor and materials to disruptively drain or freeze hydronic systems in order to cut in means of bypassing the main system, swapping out equipment, or repair. The intent of this project is to explore alternative methods to forgo the aforementioned negative impacts of service and to improve …

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 …

Dynamic Loading Experimentation And Surface Imaging Of Pressure Vessel Loadcell Fractures, Austin T. Sumner

Honors College Theses

Pressure vessels are very common pieces of equipment in industry and they are used for a variety of applications. It is standard in industry to rest pressure vessels on load cells. For some special cases, the pressure vessels are rested on load cells instead of solid foundation. Pressure vessels and their loadcells are generally designed for static environmental conditions and loading and tend to experience adverse effects when exposed to dynamic environments, such as hurricanes and earthquakes. These adverse-loading conditions cause vibrations and asymmetrical loading on the load cells, which can concurrently cause unexpected failure. This research investigates the effects …

Comparision Of Fillet-Welded Base Plate Fatigue Design For Highway Support Structures With Laboratory Research Tests, William Shea

Williams Honors College, Honors Research Projects

There are many types of vertical structures along highways that serve unique purposes. These structures include traffic signs for directing, warning, or regulating traffic, luminaires for distributing and directing light, traffic signals supporting equipment such as traffic lights, and combination structures including any combination of the aforementioned structures. Highway support structures are typically fabricated from steel or aluminum and are designed to the guidelines and specifications of the AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals. The structures are connected to a foundation by anchor bolts through a welded base plate. Often a cause …

A State Estimation Framework For Fatigue Monitoring And Prognosis Of Minimally Instrumented Structural And Biomechanical Systems, Benjamin Leblanc

Graduate College Dissertations and Theses

Fatigue damage is the continuous degradation of a material, primarily due to the formation of microcracks and resulting from the repeated application of stress cycles. Traditionally a fatigue analysis was performed during the structural design stage of a machine or structure; however, more recently there has been increased interest in the monitoring and prognosis of fatigue damage in existing and operating structures. In monitoring, the structure already exists and its mechanical properties can be estimated by processing sensor measurements and non-destructive testing. The traditional approach to fatigue monitoring is to carry out a visual inspection, find macroscopic cracks and then …

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 …

Effects Of Supplementary Cementitious Materials On Early-Age Tensile Creep And Shrinkage Of Concrete, Lucas James Bucklen

Graduate Theses, Dissertations, and Problem Reports

Determination of early-age tensile creep properties is critical for the performance of mass concrete structures at an early age. Due to the stress relaxation that tensile creep induces in concrete structures, accurate quantification of creep deformation is needed to determine the stress profile of the structure. Conventional methods of measuring tensile creep include the direct tension test where the concrete is subject to constant tensile stress. This method requires large quantities of concrete with embedded strain gauges which can only be used once. In this paper, the tensile creep parameters of concrete are found by using the restrained concrete ring …

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 …

Numerical And Semi-Analytical Estimation Of Convective Heat Transfer Coefficient For Buildings In An Urban-Like Setting, Anwar Demsis Awol

Electronic Thesis and Dissertation Repository

Urban building arrangements such as packing density, orientation and size are known to influence the microclimate surrounding each building. Studies on the impact of urban microclimatic changes on convective heat transfer coefficient (CHTC) from a stock of buildings, however, have been rare in surveyed literature. The present study focuses on numerical and analytical investigation of CHTC from building-like models with homogeneous set of equal and unequal planar and frontal densities. Consequently, the study discusses the CHTC response in relation to broader changes in the urban surface form. Part of the process involves the development of a simplified one-dimensional semi-analytical CHTC …

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 …