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Full-Text Articles in Mechanical Engineering

Swarm Behavior To Mitigate Rebound In Air Conditioning Demand Response Events, Jason Yasuto Kuwada Aug 2019

Swarm Behavior To Mitigate Rebound In Air Conditioning Demand Response Events, Jason Yasuto Kuwada

Boise State University Theses and Dissertations

Thermostatically Controlled Loads (TCLs) have shown great potential for Demand Response (DR) events. However, it has been commonly seen that DR events using TCLs may cause demand rebound, especially in homogeneous populations. To further explore the potential for DR events, as well as the negative effects, a stability and resilience analysis were performed on multiple populations and verified with agent based modeling simulations.

At the core of this study is an added thermostat criterion created from the combination of a proportional gain and the average compressor operating state of neighboring TCLs. Where DR events in TCLs are commonly controlled by ...


Isentropic Efficiency And Theoretical Analysis Of The Planetary Rotor Expander, Joseph L. James Aug 2019

Isentropic Efficiency And Theoretical Analysis Of The Planetary Rotor Expander, Joseph L. James

All Graduate Theses and Dissertations

Expanders allow pressurized fluids to undergo a pressure decrease in a controlled environment via volumetric growth to extract fluid energy. There are many types of expanders, and the objective of this thesis is to model the efficiencies of the planetary rotor expander (PRE), a century-old design undeveloped due to insufficient manufacturing capabilities (until recently). Geometric relationships are derived and mathematical models are generated to determine the efficiency of the PRE as a function of design variables. Two industrially relevant case studies show that, to maximize isentropic efficiency, the planetary rotor expander (PRE) rotational frequency is maximized and rotor geometry optimized.


Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen May 2019

Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen

Electronic Theses and Dissertations

When small drops coalesce on a superhydrophobic surface, the merged drop can jump away from the surface due to the surface energy released during the coalescence. This self-propelled behavior has been observed on various superhydrophobic surfaces and has potential applications in areas related to the heat and mass transfer, such as heat exchangers, anti-icing and anti-frost devices, thermal management and water harvesting. The jumping velocity model was obtained based on published experimental data and the balance of various energy terms described in previous studies. However, the self-propelled mechanism is still not fully understood. In this study, the self-propelled droplet phenomenon ...


Design Of Wind Turbine Tower Height And Blade Length: An Optimization Approach, Ryan Wass Sep 2018

Design Of Wind Turbine Tower Height And Blade Length: An Optimization Approach, Ryan Wass

Mechanical Engineering Undergraduate Honors Theses

The wind industry is a fast growing market and is quickly becoming competitive with traditional non-renewable energy resources. As with any developing industry, research must continually be redefined as more complex understandings of design variables are learned. Optimization studies are common ways to quickly refine design variable selections. Historical wind turbine data shows that the tower hub height to rotor diameter ratio scales almost linearly. However there is no specific rule that dictates the optimum hub height for a given diameter. This study addresses this question by using an Excel based optimization program to determine the height to diameter ratio ...


Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev Aug 2018

Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer ...


Applications Of Latent Heat Storage Using Phase Change Materials, Daniel Giroux Jun 2018

Applications Of Latent Heat Storage Using Phase Change Materials, Daniel Giroux

Honors Theses

Thermal Storage Systems are gaining more attention in recent years with the increased emphasis on more renewable energy sources. Energy storage is necessary whenever there is greater amounts of energy being produced than is required. Various improvements to the conventional heat storage system can be made by integrating latent heat storage into the conventional heat storage system. Latent heat storage can be utilized for thermal storage applications by using phase change materials, materials that will undergo a change in their physical state in the temperature range desired for heat storage.

Analysis was conducted on four different waxes considering the waxes ...


Simulation Of The Inertia Friction Welding Process Using A Subscale Specimen And A Friction Stir Welder, Ty Samual Dansie Apr 2018

Simulation Of The Inertia Friction Welding Process Using A Subscale Specimen And A Friction Stir Welder, Ty Samual Dansie

Theses and Dissertations

This study develops a method to simulate a full-scale inertia friction weld with a sub-scale specimen and modifies a direct drive friction stir welder to perform the welding process. A torque meter is fabricated for the FSW machine to measure weld torque. Machine controls are modified to enable a force control during the IFW process. An equation is created to measure weld upset due to deflection of the FSW machine. Data obtained from a full-scale inertia friction weld are altered to account for the geometrical differences between the sub-scale and full-scale specimens. The IFW are simulated with the sub-scale specimen ...


Dynamic Rops Test For Tractors Over 6,000 Kilograms, Caleb M. Lindhorst, Roger M. Hoy, Santosh Pitla, Michael F. Kocher Jan 2018

Dynamic Rops Test For Tractors Over 6,000 Kilograms, Caleb M. Lindhorst, Roger M. Hoy, Santosh Pitla, Michael F. Kocher

Biological Systems Engineering: Papers and Publications

OECD static tests (Codes 4, 6, 7, and 8) for agricultural rollover protective structures (ROPS) have become accepted standards for evaluating the ability of these structures to protect the operator during tractor rollover events. The strength properties of some materials typically used in ROPS change because of cold weather embrittlement at low temperatures. The static ROPS tests lack the ability to evaluate the strength of these structures during cold weather. The use of the dynamic ROPS test is well noted as a means for proving cold weather embrittlement resistance properties. Unfortunately, application of the OECD dynamic ROPS test (Code 3 ...


An Examination Of Ash Elutriation From A Fluidized Bed Regenerator, Dane Erickson Jan 2018

An Examination Of Ash Elutriation From A Fluidized Bed Regenerator, Dane Erickson

Graduate Theses and Dissertations

The danger of climate change looms in the minds of researchers across the world. To combat this threat, many have focused efforts on the development of clean energy. In this study, the renewable resource that is investigated is biomass, specifically red oak. Energy can be extracted from biomass by fast pyrolysis, where the feedstock is rapidly heated within a reactor to approximately 500℃ in the absence of oxygen. This produces biochar, ash, and condensable gases that, once cooled, become a bio-oil. To optimize economic feasibility, the process must operate continuously. This presents a problem—the presence of ash as a ...


Suspended Graphene-Based Gas Sensor With 1-Mw Energy Consumption, Jong-Hyun Kim, Qin Zhou, Jiyoung Chang Jan 2017

Suspended Graphene-Based Gas Sensor With 1-Mw Energy Consumption, Jong-Hyun Kim, Qin Zhou, Jiyoung Chang

Mechanical & Materials Engineering Faculty Publications

This paper presents NH3 sensing with ultra-low energy consumption for fast recovery and a graphene sheet based on a suspended microheater. Sensitivity and repeatability are important characteristics of functional gas sensors embedded in mobile devices. Moreover, low energy consumption is an essential requirement in flexible and stretchable mobile electronics due to their small dimension and fluctuating resistivity during mechanical behavior. In this paper, we introduce a graphene-based ultra-low power gas detection device with integration of a suspended silicon heater. Dramatic power reduction is enabled by a duty cycle while not sacrificing sensitivity. The new oscillation method of heating improves ...


Dynamic Behavior Of A Clamped-Clamped Bi-Stable Laminate For Energy Harvesting, Ajay V. Kumar, Andres F. Arrieta Ph.D., Myungwon Hwang Aug 2016

Dynamic Behavior Of A Clamped-Clamped Bi-Stable Laminate For Energy Harvesting, Ajay V. Kumar, Andres F. Arrieta Ph.D., Myungwon Hwang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Multi-stable laminates have many applications in morphing structures, energy harvesting devices, and metamaterials due to the specific characteristics attributed to the exhibited stable states. Changes between stable states allow for large deflections, on-demand variation of the stiffness of compliant structures embedded within these elements, and control of effective dynamic properties in periodic lattices. These changes in state can be accessed via a snap-through instability triggered by introducing a well-defined activation energy. The resulting oscillations could enable broadband energy harvesting via piezoelectric transduction and resistive circuits. In this paper, a clamped-clamped bi-stable laminate is studied to understand the behavior of the ...


Parametric And Design Analysis On Thermoelectric Generators, Shouyuan Huang Aug 2016

Parametric And Design Analysis On Thermoelectric Generators, Shouyuan Huang

Open Access Theses

In facing the limited energy source reserves and environmental problems, thermoelectric generators (TEGs) are one of the promising waste heat recovery systems. The modern TEGs for exhaust stream (e.g. from automobiles) can improve the fuel economy by around 5%, taking advantage of the recent developed thermoelectric (TE) materials.

In this work, we aimed at designing a TEG as an add-on module for a gas-phase heat exchanger with maximized power output, and without negative impact (e.g. maintaining a minimum heat dissipation rate from the hot side). We first developed a parametric optimization algorithm using response surface method (RSM) and ...


Second Law Of Thermodynamics Analysis Of An Internal Combustion Engine Fueled With Methane, Muataz Abotabik Aug 2016

Second Law Of Thermodynamics Analysis Of An Internal Combustion Engine Fueled With Methane, Muataz Abotabik

Master's Theses

The second law of thermodynamics is a powerful tool for calculating the amount of energy that can be converted to work (i.e., the exergy or availability of a system), which cannot be predicted using the first law. The objectives of this research project are to quantify the availability during the compression, combustion and expansion processes of a spark-ignited engine fueled with methane; and to highlight differences in the thermo-mechanical availability of the ideal and spark-ignition (SI) engine cycles. A cooperative single-cylinder research engine was used to measure the data required for availability analysis at equivalence ratios ranging between 0 ...


Strain Energy Absorption Corresponds To Decreased Incidence Of Ventricular Fibrillation In A Commotio Cordis Model, Kayt E. Frisch, Mark S. Link, John Van Weelden Aug 2016

Strain Energy Absorption Corresponds To Decreased Incidence Of Ventricular Fibrillation In A Commotio Cordis Model, Kayt E. Frisch, Mark S. Link, John Van Weelden

Faculty Work Comprehensive List

A healthy teenage boy is playing high school baseball, when he is struck in the chest by the ball; minutes later, his heart is experiencing ventricular fibrillation (VF) and the only way to resuscitate him is to use a defibrillator. This phenomenon, is known as Commotio Cordis (CC), and occurs as many as 20 times each year in the United States. CC most frequently occurs in sports with small balls (e.g. baseball or lacrosse) and requires a specific set of circumstances–a projectile with a certain amount of energy that impacts directly over the left ventricle of the heart ...


Using The Moment Of Inertia As A Means Of Better Controlling The Speed Of Wind Turbines, Garrett L. Muhlstadt Mar 2016

Using The Moment Of Inertia As A Means Of Better Controlling The Speed Of Wind Turbines, Garrett L. Muhlstadt

Honors Program Projects

In the following document, the possibility of using the moment of inertia as a means of speed control for a wind turbine is explored. This document gives an introduction to wind energy and current speed control methods. This information was obtained through databases found at Benner Library. Also, an experiment was used to collect data and determine the relationship between the moment of inertia and angular velocity of a turbine. A model turbine was fabricated and powered by a fan while a Logger Pro program was used to record the angular velocity of the turbine. The moment of inertia of ...


Hybrid Diesel-Electric Drivetrain For Small Agricultural Field Machines, Joseph Jackson, Joseph S. Dvorak Jan 2016

Hybrid Diesel-Electric Drivetrain For Small Agricultural Field Machines, Joseph Jackson, Joseph S. Dvorak

Biosystems and Agricultural Engineering Faculty Publications

In this project, a series electric drivetrain sized for small agricultural machinery was developed and tested. Electric drives have noted benefits in simplicity, controllability, integration with other electronics such as those that provide autonomous action, and in efficiency over a wide operating range. Their biggest drawback for agricultural use is the limited capacity of electrical energy storage. A series hybrid drivetrain provides a method to overcome these capacity constraints through the use of chemical energy storage. The series hybrid drivetrain in this research was designed using well-established components. It consisted of a diesel-electric generator, a lead acid battery pack, a ...


Cogeneration System Comparison For The Akron Water Treatment Plant, Devin J. Pearcy, Madison R. Morgan Jan 2016

Cogeneration System Comparison For The Akron Water Treatment Plant, Devin J. Pearcy, Madison R. Morgan

Williams Honors College, Honors Research Projects

Cogeneration is a process of electrical power generation that simultaneously harnesses the heat produced from that electrical generation and uses it to supply heat to a space. The Akron Water Plant was identified as potentially benefitting from this technology for two main reasons. First, they have a large and relatively constant electrical load. Second, they have ownership of a significant amount of natural gas wells at the site.

This report analyzes the economic feasibility of installing a cogeneration plant at the Akron Water Plant (AWP). Data was collected for the plant and its operations, including electricity bills, gas bills, plant ...


Wind Turbine Towers: Precast Concrete Hexcrete May Help Increase Renewable Energy Capacity With Taller Hub Height, Sri Sritharan Nov 2015

Wind Turbine Towers: Precast Concrete Hexcrete May Help Increase Renewable Energy Capacity With Taller Hub Height, Sri Sritharan

Civil, Construction and Environmental Engineering Publications

Wind-energy production has been growing rapidly in the Midwest, but not in other regions of the United States. Increased wind-turbine hub heights of 328 to 459 ft (100 to 140 m) could drastically change this. As wind-turbine towers get taller than 263 ft (80 m), a concrete solution may become more cost-effective than the steel tubular option. The Hexcrete concept was developed with the aim of revolutionizing wind-turbine towers for hub heights of 328 ft (100 m) and more. This tower uses hexagonal columns with posttensioning and rectangular/tapered panels as bracing elements. The prefabricated modules are assembled using posttensioning ...


Veloelectric: Creating A Device That Harvests Energy From Bicycles, Austin Hall, Daniel Stohr, Tj Fox Jun 2015

Veloelectric: Creating A Device That Harvests Energy From Bicycles, Austin Hall, Daniel Stohr, Tj Fox

Mechanical Engineering

Long distance mountain bikers, bike-packers, and many bikers in developing countries rely on electrical devices for safety and communication. These specific groups of people operate in areas with little to no electricity, and often times have no power to sustain their devices. The purpose of this Cal Poly senior project, VeloElectric, was to design, build, and test a kinetic energy harvester for bicycles that can be used to charge common mobile devices via USB. This senior project team created a device that attaches directly to a bicycle and uses vibrations to generate energy, which in turn powers a variety of ...


Evaluating The Optical Properties Of Tio2 Nanofluid For A Direct Absorption Solar Collector May 2015

Evaluating The Optical Properties Of Tio2 Nanofluid For A Direct Absorption Solar Collector

Faculty of Engineering University of Malaya

Recent studies specify that designated nanofluids may increase the proficiency of direct absorption solar thermal collectors. To determine the efficiency of nanofluids in solar applications, their capability to change light energy to thermal energy must be identified (i.e., the absorption spectrum of the solar material). In view of that, this study compares model predictions to spectroscopic measurements of extinction coefficients over wavelengths that are important for solar energy (200- 1100nm). In the first decade of nanofluid research, most of the focus was on measuring and modeling the fundamental thermophysical properties of nanofluids (i.e., thermal conductivity, density, viscosity, and ...


An Experimental Investigation On A Single Tubular Sofc For Renewable Energy Based Cogeneration System Apr 2015

An Experimental Investigation On A Single Tubular Sofc For Renewable Energy Based Cogeneration System

Faculty of Engineering University of Malaya

Having negative impacts on environment and the scarcity of resources of conventional fossil fuels, fuel cell technology draws more attention as an alternative for providing the electrical energy in parallel with thermal energy. In this study, a single tubular solid oxide fuel cell (SOFC) with an electrolyte of Yttria-Stabilized Zirconia 8 mol% ceramic powder was experimentally investigated. The investigation illustrated the effects of three different fuel flow-rates (175 ml/min, 250 ml/min and 325 ml/min) and two operating temperatures (650 degrees C and 750 degrees C) on the output electrical and thermal powers. The highest electrical voltage (open ...


Performance Of Solid Oxide Iron-Air Battery Operated At 550°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang Feb 2015

Performance Of Solid Oxide Iron-Air Battery Operated At 550°C, Xuan Zhao, Yunhui Gong, Xue Li, Nansheng Xu, Kevin Huang

Kevin Huang

“Metal-air” batteries have garnered much attention in recent years due to their high intrinsic specific energy and use of inexhaustible and storage-free oxygen source -air- for the “metal-oxygen” reaction. In this study, we report theperformance of a new type of all solid-state “iron-air” battery operated at 550°C. The results show that CeO2 nanoparticles incorporated into the Fe-Fe3O4 redox-couple can improve the specific energy (Wh/kg) and round trip efficiency by 15% and 29%, respectively, over the baseline Fe-Fe3O4 battery. Use of supported Fe-Fe3O4 nanoparticles as the redox couple can increase the specific energy and round-trip efficiency by 13% and ...


Classroom Exercise: Intro To Mechanical And Industrial Engineering, Erin Baker Jan 2015

Classroom Exercise: Intro To Mechanical And Industrial Engineering, Erin Baker

Sustainability Education Resources

This classroom exercise was developed for Introduction to Mechanical and Industrial Engineering; Engineering Sustainability: Energy and the Environment. This is a freshman class with a class size of about 200. It is intended to get students to think critically about energy in the economy; to recognize the power of technological change; and to inspire them to work toward solving climate change.


Design And Biomechanical Performance Analysis Of A User-Friendly Orthotic Device Jan 2015

Design And Biomechanical Performance Analysis Of A User-Friendly Orthotic Device

Faculty of Engineering University of Malaya

Material selection and proper design are essential for developing a new product, especially biomedical devices. Stance-control-orthosis (SCO) are walking assistive device for the patients with weak quadriceps. This manuscript presents the development of a prefabricated SCO with suitable material and design. It is 45% lighter than commercially available prefabricated device. It contains some adjustable features to make it competent for wide range of patients in terms of height (153-183 cm) and weight. Finite element analysis (FEA) was used for selecting the best material and optimizing weight of different components of this device. Basic structures the device were made of aluminum ...


Analysis And Optimization Of The Scheffler Solar Concentrator, Simone Alberti Dec 2014

Analysis And Optimization Of The Scheffler Solar Concentrator, Simone Alberti

Master's Theses and Project Reports

The Scheffler reflector is a new solar concentrator design which maintains a fixed focus while only having a single axis tracking mechanism. This design makes the construction and operation of high temperature solar concentrators accessible to developing nations. In this project, I wrote computer simulation codes to better understand the dynamics and the effect of deformation or deviations from ideal conditions in order to define necessary manufacturing and operational tolerances. These tools and knowledge drove the prototyping of new reflector concepts by myself and other students on my team. A fiberglass prototype was able to drive the cost of a ...


Waste Heat Recovery Options In A Large Gas-Turbine Combined Power Plant, Ularee Upathumchard Oct 2014

Waste Heat Recovery Options In A Large Gas-Turbine Combined Power Plant, Ularee Upathumchard

Open Access Theses

This study focuses on power plant heat loss and how to utilize the waste heat in energy recovery systems in order to increase the overall power plant efficiency. The case study of this research is a 700-MW natural gas combined cycle power plant, located in a suburban area of Thailand. An analysis of the heat loss of the combustion process, power generation process, lubrication system, and cooling system has been conducted to evaluate waste heat recovery options. The design of the waste heat recovery options depends to the amount of heat loss from each system and its temperature. Feasible waste ...


Energy Generator Exploration Station Senior Project Report, Evan Carr, Christopher Scharff, Andrea Govea Jun 2014

Energy Generator Exploration Station Senior Project Report, Evan Carr, Christopher Scharff, Andrea Govea

Mechanical Engineering

The mission of Team EnGen is to create a safe and reliable, human powered energy generation system for the Exploration Station. This project was proposed by the Exploration Station in response to a grant received by Pacific Gas and Electric (PG&E) that allocated funds for an energy conservation exhibit. This system will take the form of a model energy truck and a darkened neighborhood display that the user powers through peddling, turning the generator to create the electricity that will light up the display. The Exploration Station and Team EnGen agree that this style of design is accessible to ...


Looking For Small Changes In Heat Capacity Using A Differential Scanning Calorimeter, Will Linthicum Jun 2014

Looking For Small Changes In Heat Capacity Using A Differential Scanning Calorimeter, Will Linthicum

Honors Theses

One of the major difficulties in development of renewable energy is the lack of an adequate and economical means of energy storage. In the case of concentrated solar power a large mass of thermal fluid is required to store a reasonable amount of energy. This is primarily because the fluids tend to have a low specific heat capacity. Formulating composites of these fluids can enhance their specific heat capacity and avails opportunities to make concentrated solar power more attractive. In most cases, the specific heat capacity of composite materials is a weighted average of the individual component heat capacities. This ...


A Novel Microgrid Demand-Side Management System For Manufacturing Facilities, Terance J. Harper, William J. Hutzel, James C. Foreman, Aaron L. Adams, Athula Kulatunga Jan 2014

A Novel Microgrid Demand-Side Management System For Manufacturing Facilities, Terance J. Harper, William J. Hutzel, James C. Foreman, Aaron L. Adams, Athula Kulatunga

Purdue Polytechnic Masters Theses

Thirty-one percent of annual energy consumption in the United States occurs within the industrial sector, where manufacturing processes account for the largest amount of energy consumption and carbon emissions. For this reason, energy efficiency in manufacturing facilities is increasingly important for reducing operating costs and improving profits. Using microgrids to generate local sustainable power should reduce energy consumption from the main utility grid along with energy costs and carbon emissions. Also, microgrids have the potential to serve as reliable energy generators in international locations where the utility grid is often unstable.

For this research, a manufacturing process that had approximately ...


Why Waste The Wind? A Look Into Small Scale Wind Energy, Mitchell Negus, Jon Swanton, Ben Chilcoat, Mark Settembrino Jan 2014

Why Waste The Wind? A Look Into Small Scale Wind Energy, Mitchell Negus, Jon Swanton, Ben Chilcoat, Mark Settembrino

Student Showcase

The human race’s dependence on fossil fuels for energy generation has started to cause major changes in the environment. Climate change is a universal issue and it is evident that our current energy schematic is not sustainable. At the University of Massachusetts, small-scale wind power has the potential to be a key component in UMass’ energy portfolio as the university shifts from reliance on fossil fuels to renewable energy. Strategically placed turbines would produce clean, renewable energy, reduce greenhouse gas emissions, and help to decentralize energy dependence on the Central Heating Plant. Small-scale turbines, like the eddyGT, are tested ...