Mechanical Engineering Commons^™

Streaming Potential Generated By A Pressure-Driven Flow Over Superhydrophobic Stripes, Hui Zhao

Mechanical Engineering Faculty Research

The streaming potential generated by a pressure-driven flow over a weakly charged slip-stick surface [the zeta potential of the surface is smaller than the thermal potential (25 mV)] with an arbitrary double layer thickness is theoretically studied by solving the Debye–Huckel equation and Stokes equation. A series solution of the streaming potential is derived. Approximate expressions for the streaming potential in the limits of thin double layers and thick double layers are also given in excellent agreement with the full solution. To understand the impact of the slip, the streaming potential is compared against that over a homogeneously charged smooth …

Influence Of Stitch Density And Stitch Thread Thickness On Compression After Impact Strength Of Stitched Composites, Kwek Tze Tan, N. Watanabe, Y. Iwahori, T. Ishikawa

Mechanical Engineering Faculty Research

This study aims to investigate the influence of stitch density and stitch thread thickness on compression after impact (CAI) strength of stitched composites. Unstitched laminated composites and specimens stitched with varying stitch density and stitch thread thickness are subjected to impact damage and then compressive loading. It is shown that stitched composites have higher CAI strength than unstitched counterpart due to smaller impact-induced delamination area, where local buckling occurs during compressive failure. However, it is revealed that the effectiveness of stitching in suppressing delamination growth and inhibiting sublaminate buckling under compressive loading is intimately related to stitch density. It is …

Opposing Effects Of Recirculated Gases During Cranking On Cold Start Of Diesel Engines, Rafik N. Rofail

Wayne State University Dissertations

ABSTRACT

OPPOSING EFFECTS OF RECIRCULATED GASES DURING CRANKING ON COLD START OF DIESEL ENGINES

by

RAFIK ROFAIL

August 2011

Advisor: Dr. Naeim Henein

Major: Mechanical Engineering

Degree: Doctor of Philosophy

Enhancing cold start of DI diesel engines is the motivation behind this study. A new control strategy is proposed to reduce the cranking period and the white smoke emissions. In the strategy, the gases leaving the cylinder during the cranking period are recycled back into the intake manifold using two different methods. In the first method the engine-out gases during cranking are recirculated into the intake manifold and their rate …

Power Curve Data Analysis For Rim Driven Wind Turbine, Aerel J. Rankin, Svetlana V. Poroseva, Bob O. Hovsapian

Early Career Technical Journal (ECTJ)

Proceedings of the ASME Early Career Technical Conference, November 4-5, 2011. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia

pp. 27-32

Development Of Energy Absorbing Laminated Fiberglass Composites Using Electrospun Glass Nanofibers, Evan Kimbro

Dissertations

The ability to predict failure of composite laminates due to delaminations is critical because of its subsurface nature. Traditional strengthening methods such as stitching and Z-pinning, while improving interlaminar properties in woven composites, lead to a reduction of the in-plane properties. Electrospun non-woven sheets of nanofibrous mat applied at interfacial regions offer an option to traditional treatments. Applications where protrusion energy must be dissipated completely would benefit the most from the use of the electrospinning treatment. Examples are bullet proof vests and vehicle armor. Penetration of a projectile through a composite material may be avoided by creating more energy absorbent …

Test 2009: Case Ih Steiger 450, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S802 Case-Ih Puma 215, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

More Carrot Than Stick: Encouraging Computer Programming In Thermal Design Projects, Kevin D. Cole

Department of Mechanical and Materials Engineering: Faculty Publications

Students will do almost anything to avoid using thermal-property tables. In this paper, Matlab-based thermal-property software is described as an enticement for students to do computer programming in the design of thermal systems. Downloaded shareware was used for steam properties in a steam-cycle project, and an air-property package was developed for use with a gas-turbine project. Although the use of computer programming required considerable effort by both instructor and students, most students did gain a better appreciation of the utility of writing computer programs as part of engineering design. Student evaluations of the course were not significantly affected compared to …

Role Of Helmet In The Mechanics Of Shock Wave Propagation Under Blast Loading Conditions, Shailesh G. Ganpule, Linxia Gu, Aaron L. Alai, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

The effectiveness of helmets in extenuating the primary shock waves generated by the explosions of improvised explosive devices is not clearly understood. In this work, the role of helmet on the overpressurization and impulse experienced by the head were examined. The shock wave–head interactions were studied under three different cases: (i) unprotected head, (ii) head with helmet but with varying head–helmet gaps and (iii) head covered with helmet and tightly fitting foam pads. The intensification effect was discussed by examining the shock wave flow pattern and verified with experiments. A helmet with a better protection against shock wave is suggested.

Effects Of Mass Layer Nonuniformity On A Quartz-Crystal Microbalance, Nan Liu, Jiashi Yang, Weiqiu Chen

Department of Mechanical and Materials Engineering: Faculty Publications

We study the effects of the nonuniform thickness of a thin mass layer on a quartz-crystal microbalance. A theoretical analysis is performed on thickness-shear (TSh) vibration of an AT-cut quartz plate with a nonuniform mass layer. Mindlin’s 2-D equation for TSh vibration of a quartz plate is used. An elliptical mass layer with stepped thickness is considered which allows an exact analysis based on the plate equation. Free vibration frequencies and modes are obtained. The effects of the mass layer nonuniformity are examined. Results show that a mass layer thicker at the center tends to confine more modes under the …

Intermediate Layers In Tandem Organic Solar Cells, Yongbo Yuan, Jinsong Huang, Gang Li

Department of Mechanical and Materials Engineering: Faculty Publications

Tandem structures can boost the efficiency of organic solar cell to more than 15%, compared to the 10% limit of single layer bulk heterojunction devices. Design and fabricating of intermediate layers plays a very important role to achieve high device performance. This article will review the main experimental progresses of tandem organic solar cells, and focus on the intermediate layers (charge recombination layers) in both thermal evaporated and solution processed organic tandem solar cell devices.

A Model Of Giant Vacuole Dynamics In Human Schlemm’S Canal Endothelial Cells, Ryan M. Pedrigi, David Simon, Ashley Reed, W. Daniel Stamer, Darryl R. Overby

Department of Mechanical and Materials Engineering: Faculty Publications

Aqueous humour transport across the inner wall endothelium of Schlemm’s canal likely involves flow through giant vacuoles and pores, but the mechanics of how these structures form and how they influence the regulation of intraocular pressure (IOP) are not well understood. In this study, we developed an in vitro model of giant vacuole formation in human Schlemm’s canal endothelial cells (HSCECs) perfused in the basal-to-apical direction (i.e., the direction that flow crosses the inner wall in vivo) under controlled pressure drops (2 or 6 mmHg). The system was mounted on a confocal microscope for time-lapse en face imaging, and cells …

Solar Furnace: Heliostat And Concentrator Design, Tyler Heagney, Andrew Schiller, Matthew Gaide

Symposium on Research and Creative Expression (SORCE)

In recent decades, solar energy has been shown as a viable, clean, and abundant alternative to fossil fuels. Many methods of solar energy collection are being researched, with solar thermal electrochemistry being one of the most promising. Solar thermal electrochemistry uses sunlight to heat a furnace to temperatures nearing 2000 K. At these temperatures, metallic oxides can be decomposed to metals and oxygen with minimal electrical work. Achieving these high temperatures requires a solar furnace that consists of a heliostat to track and reflect the sun’s rays into a concentrator, which then focuses the sunlight to a single point in …

Oxidation Performance Of Ultra-High Temperature Ceramics In Air And A Simulated Combustion Environment, Tim Englert

Symposium on Research and Creative Expression (SORCE)

The oxidation resistance of various (Zr or Hf)B2-based ceramics will be tested in order to evaluate their respective performances in both furnace and oxyacetylene torch environments. Furnace testing will allow experimentation at temperatures similar to hypersonic travel or reentry conditions (>2000°C); use of an oxyacetylene torch flame will enable the replication of severe thermal gradients and combustion conditions. Oxidation resistance will be firstly quantified by measuring a sample’s change in mass after exposure to the testing environment for a defined time period. A sample that experiences a smaller change in mass is better able to resist oxidation. Oxidation rate …

Solar Thermal Electrolytic Production Of Mg From Mgo, William Sheline, L. Matthews, N. Lindenke, S. Duncan, R. Palumbo

Symposium on Research and Creative Expression (SORCE)

The electrolytic production of Mg from MgO was experimentally and theoretically investigated near 1550 K. The oxide was dissolved in either CaF2 or MgF2. The cathode was Mo and the anode was either Pt or Cgr. Mg evolved as a gas, was quenched on cooling coils at the exit of the reactor and was collected for analysis. A thermodynamic cycle study indicates that the ideal thermal efficiency for the solar process is 35 percent for an inert anode and 39 percent for a carbon anode, making the process competitive with the industrial potential of other solar to metal processes. Experimental …

Decoupled Solar Thermal Chemical Electrolysis Of Water To Produce Hydrogen, Melissa Meyer, Megan Wilken

Symposium on Research and Creative Expression (SORCE)

Solar thermal chemical research at Valparaiso University focuses on using concentrated solar energy to produce hydrogen, which can be used to generate electricity in fuel cells. A two-step solar electrolytic process has been proposed for chemical systems such as Fe2O3/Fe3O4, Co3O4/CoO, and Mn2O3/MnO. This new process produces hydrogen using ideally 63-82% less electricity than the traditional electrolytic process. Theoretical solar-to-electrical efficiencies are approximately 19-40%, a range comparable to similar solar thermal chemical processes. Preliminary experimental work with the Fe2O3/Fe3O4 system has validated the chemical possibility of each step of the process. Future work seeks to determine if the proposed processes …

Oxidation Performance Of Ultra-High Temperature Ceramics In Air And A Simulated Combustion Environment, Kevin Fedde

Symposium on Research and Creative Expression (SORCE)

The objective of this experiment is to evaluate the oxidation performance and heat resistance of the Ultra-high Temperature Ceramics (UHTCs) ZrB2 and HfB2 under high temperature, high heat flux, ablative, and oxidative environments. The investigation of UHTCs such as ZrB2 and HfB2 could potentially lead to new, easily reusable thermal protection systems (TPS) for space craft. The UHTC samples will be oxidized using an oxy-acetylene torch and a high temperature air furnace. The torch will expose the samples to rapid heating, high velocity combustion gasses, and sample temperatures in excess of 3000°C. The furnace will expose the samples to temperatures …

Parametric Analysis Of A Detonation-Type Turbofan, Yashwanth M. Swamy

Mechanical and Aerospace Engineering Theses - Archive

A new type of turbofan which detonates a fuel-air mixture was theoretically found to perform better than a conventional turbofan. A continuous detonation process is described and considered inside the core of the turbofan. The detonation-type turbofan needs certain modifications to detonate the fuel-air mixture at the core of the turbofan, namely, an annular detonation chamber to achieve continuous detonation. A parametric analysis of the new detonation-type turbofan was developed and used to calculate the performance parameters.

Self Assembly In Additive Manufacturing: Opportunities And Obstacles, Nathan B. Crane, J. Tuckerman, G. N. Nielson

Faculty Publications

Purpose

Additive manufacturing offers substantial flexibility in shape, but much less flexibility in materials and functionality—particularly at small size scales. A system for automatically incorporating microscale components would enable the fabrication of objects with more functionality. This paper considers the potential of self assembly to serve as an automated programmable integration method. In particular, it addresses the ability of random self assembly processes to successfully assemble objects with high performance despite the possibility of assembly errors.

Methodology

A self-assembled thermoelectric system is taken as a sample system. The performance expectations for these systems are then predicted using modified one-dimensional models …

Improving Sample Collection Of Trace Particles Of Mock Explosive On Nano Coated Sensor, Daniel Woldemichael Yebo

Electronic Theses and Dissertations

In protection against explosive-based terrorism, development and mass deployment of miniature sensors can play a tremendous role. In trace explosive detection, one of the challenges is bringing explosive vapor samples from the environment to the sensor element. Such collection of a selective and sufficient amount of air sample will enable the device detect the explosive at lower concentration. This can be done by adsorption of the explosive vapor on a substrate. This research implements the idea by developing a nano coated sensor on a lead zirconate titanate (PZT) substrate. The effects of varying the amount of polyethyleneimine in the nano …