Other Mechanical Engineering Commons^™

Ionization In Diesel Combustion For On-Board Diagnostics And Engine Control, Tamer Hassan Badawy

Wayne State University Dissertations

Diesel engines have been known for their high thermal efficiency and specific power output, but there is concern about engine-out NOx and particulate matter emissions. To meet the current emission standards, advanced diesel engines are fitted with electronically controlled fuel injection systems and sophisticated and expensive after-treatment devices. Further improvements are still needed to meet future goals in better fuel economy and the more stringent emission standards. In order to meet these goals, there is a need for the control of the combustion process to reduce engine-out emissions in real-time and reduce the demand on the after-treatment devices. This requires …

Simulations And Experiments Of Fuel Injection, Mixing And Combustion In Di Gasoline Engines, Yi Zheng

Wayne State University Dissertations

Direct Injection (DI) has been known for its improved performance and efficiency in gasoline spark-ignition engines. In order to take all the advantages of the GDI technology, it is important to investigate in detail the interactions of fuel spray and combustion system, such as air-fuel mixing, in-cylinder flow development, surface wetting, and turbulence intensity. The characterizations of the internal nozzle flow of DI injector are first studied using the multidimensional computational fluid dynamic (CFD) simulation. In the meanwhile the numerical and experimental studies are carried out to observe the external spray and wall impingements in an optical constant volume vessel. …

Solution-Processed Nanoparticle Super-Float-Gated Organic Field-Effect Transistor As Un-Cooled Ultraviolet And Infrared Photon Counter, Yongbo Yuan, Qingfeng Dong, Bin Yang, Fawen Guo, Qi Zhang, Ming Han, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

High sensitivity photodetectors in ultraviolet (UV) and infrared (IR) range have broad civilian and military applications. Here we report on an un-cooled solution-processed UV-IR photon counter based on modified organic field-effect transistors. This type of UV detectors have light absorbing zinc oxide nanoparticles (NPs) sandwiched between two gate dielectric layers as a floating gate. The photon-generated charges on the floating gate cause high resistance regions in the transistor channel and tune the source-drain output current. This ‘‘super-float-gating’’ mechanism enables very high sensitivity photodetectors with a minimum detectable ultraviolet light intensity of 2.6 photons/µm²s at room temperature as well …

Analysis Of Electrically-Forced Vibrations Of Piezoelectric Mesa Resonators, Huijing He, Guo-Quan Nie, Jin-Xi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We study the electrically forced thickness-shear and thickness-twist vibrations of stepped thickness piezoelectric plate mesa resonators made of polarized ceramics or 6-mm class crystals. A theoretical analysis based on the theory of piezoelectricity is performed, and an analytical solution is obtained using the trigonometric series. The electrical admittance, resonant frequencies, and mode shapes are calculated, and strong energy trapping of the modes is observed. Their dependence on the geometric parameters of the resonator is also examined.

Review Of Electrochemical And Electrodischarge Machining, Kamlakar P. Rajurkar, M. M. Sundaram, A. P. Malshe

Department of Mechanical and Materials Engineering: Faculty Publications

Electrochemical and electro-discharge machining processes are the two major electro-machining processes with unique capabilities. Electrical Discharge Machining (EDM) and Electrochemical Machining (ECM) offer a better alternative or sometimes the only alternative in generating accurate 3-D complex shaped macro, micro and nano features and components of difficult–to-machine materials. Technological advances reported in electrochemical and electro discharge machining processes, which reflect the state of the art in academic and industrial research and applications, are briefly reviewed in this paper.

Wire Electro-Discharge Machining Of Titanium Alloy, Farnaz Nourbakhsh, Kamlakar P. Rajurkar, Ajay P. Malshe, Jian Cao

Department of Mechanical and Materials Engineering: Faculty Publications

This paper presents an experimental investigation of wire electro-discharge machining (WEDM) of titanium alloy. The objective is to investigate the effect of seven process parameters including pulse width, servo reference voltage, pulse current, and wire tension on process performance parameters (such as cutting speed, wire rupture and surface integrity). A Taguchi L18 design of experiment (DOE) has been applied. All experiments have been conducted using Charmilles WEDM. It was also found that the cutting speed increases with peak current and pulse interval. Surface roughness was found to increase with pulse width and decrease with pulse interval. The Analysis of Variance …

Selective Detection And Automated Counting Of Fluorescently-Labeled Chrysotile Asbestos Using A Dual-Mode High-Throughput Microscopy (Dm-Htm) Method, Myoung-Ock Cho, Hyo Mi Chang, Donghee Lee, Yeon Gyu Yu, Hwataik Han, Jung Kyung Kim

Department of Mechanical and Materials Engineering: Faculty Publications

Phase contrast microscopy (PCM) is a widely used analytical method for airborne asbestos, but it is unable to distinguish asbestos from non-asbestos fibers and requires time-consuming and laborious manual counting of fibers. Previously, we developed a high-throughput microscopy (HTM) method that could greatly reduce human intervention and analysis time through automated image acquisition and counting of fibers. In this study, we designed a dual-mode HTM (DM-HTM) device for the combined reflection and fluorescence imaging of asbestos, and automated a series of built-in image processing commands of ImageJ software to test its capabilities. We used DksA, a chrysotile-adhesive protein, for selective …

Photovoltaic Device, Jinsong Huang, Bin Yang, Yongbo Yuan

Department of Mechanical and Materials Engineering: Faculty Publications

An apparatus includes a substrate; and a photoactive layer disposed on the substrate. The photoactive layer includes an electron acceptor material; an electron donor material; and a material having dipoles.

Testing The Fuel Efficiency Of Tractors With Continuously Variable And Standard Geared Transmissions, Christopher N. Howard, Michael F. Kocher, Roger M. Hoy, Erin E. Blankenship

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A John Deere 8295R IVT tractor with a continuously variable transmission (CVT) and a John Deere 8295R PowerShift (PST) tractor with a standard geared transmission (GT) were tested for fuel consumption at three different travel speeds with six different load levels applied per speed. The JD 8295R PST tractor was tested both at full throttle (FT) and shifted up two gears and throttled back (SUTB) to achieve the same travel speed as at full throttle. For each travel speed with each transmission mode, fuel consumption was determined to be linearly related to drawbar power. Linear regression analyses were performed, and …

Development Of Dynamic Thermal Performance Metrics For Eco-Roof Systems, Seth Sinclair Moody

Dissertations and Theses

In order to obtain credit for an eco-roof in building energy load calculations the steady state and time-varying thermal properties (thermal mass with evapotranspiration) must be fully understood. The following study presents results of experimentation and modeling in an effort to develop dynamic thermal mass performance metrics for eco-roof systems. The work is focused on understanding the thermal parameters (foliage & soil) of an eco-roof, further validation of the EnergyPlus Green Roof Module and development of a standardized metric for assessing the time-varying thermal benefits of eco-roof systems that can be applied across building types and climate zones. Eco-roof foliage, …

Generalizable Methods For Modeling Lumbar Spine Kinematics, Craig Joseph Simons

Electronic Theses and Dissertations

A more complete understanding of lumbar spine kinematics could improve diagnoses and treatment of low back pathologies and may advance the development of biomechanical models. Kinematics describes motion of the five lumbar vertebrae without consideration for the forces that cause the motion. Despite considerable attention from researchers and clinicians, lumbar spine kinematics are not fully understood because the anatomy is not accessible for direct observation and the complex governing biomechanics produce small magnitude, coupled intervertebral movements.

The overall goal of this project was to develop a descriptive model of intervertebral lumbar spine kinematics that is applicable to a generalizable subject …

Analytical And Numerical Modeling Of Assembly Procedures Of Steel Fulcra Of Bascule Bridges, Sriharsha Garapati

USF Tampa Graduate Theses and Dissertations

To model shrink-fitting in metal components, an analytical model for two long compound cylinders with temperature dependent material properties and interference between them is developed for calculating transient temperatures and stresses. A finite element model is developed for the same geometry which incorporated the temperature dependent material properties. A convergence study is performed on the finite element and analytical model. The finite element model is validated by comparing the approximations of finite element model with the analytical solution.

In an assembly procedure of fulcrums for bascule bridges, called AP1, the trunnion is shrink-fitted into a hub, followed by shrink fitting …

Shield Design For Maximum Deformation In Shape-Shifting Surfaces, Daniel Eduardo Perez

USF Tampa Graduate Theses and Dissertations

This research presents the initial studies and results on shield design for Shape-Shifting Surfaces (SSSs) seeking maximum compression and maximum expansion of a unit-cell. Shape-Shifting Surfaces (SSSs) are multilayered surfaces that are able to change shape while maintaining their integrity as physical barriers. SSSs are composed of polygonal unit-cells, which can change side lengths and corner angles. These changes are made possible by each side and corner consisting of at least two different shields, or layers of material. As the layers undergo relative motion, the unit-cell changes shape. In order for the SSS to retain its effectiveness as a barrier, …

Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky

Faculty Publications

In electrowetting, a droplet/substrate contact angle is modulated by applying a potential difference between the droplet and the substrate. Typically, the droplet potential is changed via an auxiliary electrode dipped in the droplet. Here, it is shown that electrochemical reactions lead to a potential drop on the auxiliary electrode in electrowetting, which degrades the droplet contact angle modulation. The magnitude of this effect depends on the voltage polarity. This problem can be addressed by using a dielectric layer, such as SiO2, which can prevent electrochemical reactions with the electrowetting substrate and the auxiliary electrode.

High Performance Low Temperature Solid Oxide Fuel Cells With Novel Electrode Architecture, Yu Chen, Qian Liu, Zhibin Yang, Fanglin Chen, Minfang Han

Faculty Publications

In this study, we have fabricated high performance low temperature solid oxide fuel cells (LT-SOFCs) with both acicular anodes and cathodes with thin Gd-doped ceria (GDC) electrolyte film. The acicular Ni-Gd_0.1Ce_0.9O_2−δ (Ni-GDC) anode was prepared using freeze drying tape casting, while the hierarchically porous cathode with nano-size Sm_0.5Sr_0.5CoO₃ (SSC) particles covering an acicular GDC skeleton was prepared by a combination of freeze drying tape casting and self-rising approaches. The acicular electrodes with 5–200 μm pores/channels enhance mass transport, while SSC particles of about 50 nm in the cathode promote …

Energy Trapping Of Thickness-Shear And Thickness-Twist Modes In A Partially Electroded At-Cut Quartz Resonator, Huijing He, Guoquan Nie, Jinxi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

The thickness-shear and thickness-twist vibrations of a finite and partially electroded AT-cut quartz resonator are investigated. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56 . An analytical solution is obtained using Fourier series from which the free vibration resonant frequencies, mode shapes, and energy trapping are calculated and examined.

Sustainability For Die Manufacturing: Comparative Study Of Wedm And Milling, Matthew S. Kalus

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

Sustainability is more important in today's culture due to the increasing demand for a more eco-friendly society. Concentrations in minimizing and reducing environmental impacts, energy and natural resources have been forthcoming in industry. The tool, mold and die industries are the most well known industries that machine harder materials using mills and WEDM. The objective of this thesis was to compare the sustainability differences in both of these machines utilizing the accepted standards for evaluating the manufacturing process performance for sustainability. These standards include the evaluation of the process parameters, raw materials, power, tools and fluids which all contribute to …

Handitrike - Recumbent Tricycle, Sean Higginson, Kevin Howie, Vinay Patel

Mechanical Engineering

This report covers the design and construction of the recumbent racing tricycle for Mr. Robert T. Kelly, a disabled veteran. Unfortunately Rob’s right leg is five inches shorter than his left one and therefore is unable to properly operate standard cranks. Our team HandiTrike is composed of Sean Higginson, Kevin Howie, and Vinay Patel and our project requires us to come up with a design that is feasible to complete within the given three quarters, as well as allow Rob to gain full use of his tricycle. Currently Rob ‘s trike uses the standard crank set up found on most …

Formula Sae Turbocharger Engine Development, Eric Griess, Kevin Mccutcheon, Matthew Roberts, William Chan

Mechanical Engineering

This project, Formula SAE Turbocharger System Development, was sponsored by the Cal Poly, San Luis Obispo Formula SAE team. The team proposed this project in order to have a powerful yet lightweight engine so they can be extremely competitive at their competition. The baseline output of the single cylinder 450cc engine (2006 Yamaha WR450F) was 46 horsepower and 27 ft-lb of torque. The goal of this project was to increase the output of that engine to 60 horsepower and 35 ft-lb through the use of a turbocharger.

A Study Of Hdpe In High Pressure Of Hydrogen Gas: Measurement Of Permeation Parameters And Fracture Criteria, Sompong Prachumchon

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

The permeation parameters of hydrogen gas in high density polyethylene (HDPE) system are sought by comparison with a diffusion model. The method of Green’s functions is used to obtain solutions for the diffusion model. Permeation parameters are found from transient experimented data during two processes; pressurization followed by depressurization. The mechanical compression of HDPE during the pressurization process resulted in lower diffusivity coefficient values and higher solubility values. The results show that the diffusivity coefficient value in the pressurization process is 37% of that during the depressurization process. At the start of the depressurization process, a short-duration fast flow rate …